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go/src/cmd/compile/internal/gc/ssa.go
David Chase d08010f94e [dev.ssa] cmd/compile: PPC64, FP to/from int conversions. 
Passes ssa_test.

Requires a few new instructions and some scratchpad
memory to move data between G and F registers.

Also fixed comparisons to be correct in case of NaN.
Added missing instructions for run.bash.
Removed some FP registers that are apparently "reserved"
(but that are also apparently also unused except for a
gratuitous multiplication by two when y = x+x would work
just as well).

Currently failing stack splits.

Updates #16010.

Change-Id: I73b161bfff54445d72bd7b813b1479f89fc72602
Reviewed-on: https://go-review.googlesource.com/26813
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2016-08-15 14:47:49 +00:00

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// Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package gc
import (
"bytes"
"fmt"
"html"
"os"
"strings"
"cmd/compile/internal/ssa"
"cmd/internal/obj"
"cmd/internal/sys"
)
var ssaEnabled = true
var ssaConfig *ssa.Config
var ssaExp ssaExport
func initssa() *ssa.Config {
ssaExp.unimplemented = false
ssaExp.mustImplement = true
if ssaConfig == nil {
ssaConfig = ssa.NewConfig(Thearch.LinkArch.Name, &ssaExp, Ctxt, Debug['N'] == 0)
if Thearch.LinkArch.Name == "386" {
ssaConfig.Set387(Thearch.Use387)
}
}
return ssaConfig
}
func shouldssa(fn *Node) bool {
switch Thearch.LinkArch.Name {
default:
// Only available for testing.
if os.Getenv("SSATEST") == "" {
return false
}
case "amd64", "amd64p32", "arm", "386", "arm64":
// Generally available.
}
if !ssaEnabled {
return false
}
// Environment variable control of SSA CG
// 1. IF GOSSAFUNC == current function name THEN
// compile this function with SSA and log output to ssa.html
// 2. IF GOSSAHASH == "" THEN
// compile this function (and everything else) with SSA
// 3. IF GOSSAHASH == "n" or "N"
// IF GOSSAPKG == current package name THEN
// compile this function (and everything in this package) with SSA
// ELSE
// use the old back end for this function.
// This is for compatibility with existing test harness and should go away.
// 4. IF GOSSAHASH is a suffix of the binary-rendered SHA1 hash of the function name THEN
// compile this function with SSA
// ELSE
// compile this function with the old back end.
// Plan is for 3 to be removed when the tests are revised.
// SSA is now default, and is disabled by setting
// GOSSAHASH to n or N, or selectively with strings of
// 0 and 1.
name := fn.Func.Nname.Sym.Name
funcname := os.Getenv("GOSSAFUNC")
if funcname != "" {
// If GOSSAFUNC is set, compile only that function.
return name == funcname
}
pkg := os.Getenv("GOSSAPKG")
if pkg != "" {
// If GOSSAPKG is set, compile only that package.
return localpkg.Name == pkg
}
return initssa().DebugHashMatch("GOSSAHASH", name)
}
// buildssa builds an SSA function.
func buildssa(fn *Node) *ssa.Func {
name := fn.Func.Nname.Sym.Name
printssa := name == os.Getenv("GOSSAFUNC")
if printssa {
fmt.Println("generating SSA for", name)
dumplist("buildssa-enter", fn.Func.Enter)
dumplist("buildssa-body", fn.Nbody)
dumplist("buildssa-exit", fn.Func.Exit)
}
var s state
s.pushLine(fn.Lineno)
defer s.popLine()
if fn.Func.Pragma&CgoUnsafeArgs != 0 {
s.cgoUnsafeArgs = true
}
if fn.Func.Pragma&Nowritebarrier != 0 {
s.noWB = true
}
defer func() {
if s.WBLineno != 0 {
fn.Func.WBLineno = s.WBLineno
}
}()
// TODO(khr): build config just once at the start of the compiler binary
ssaExp.log = printssa
s.config = initssa()
s.f = s.config.NewFunc()
s.f.Name = name
s.exitCode = fn.Func.Exit
s.panics = map[funcLine]*ssa.Block{}
if name == os.Getenv("GOSSAFUNC") {
// TODO: tempfile? it is handy to have the location
// of this file be stable, so you can just reload in the browser.
s.config.HTML = ssa.NewHTMLWriter("ssa.html", s.config, name)
// TODO: generate and print a mapping from nodes to values and blocks
}
defer func() {
if !printssa {
s.config.HTML.Close()
}
}()
// Allocate starting block
s.f.Entry = s.f.NewBlock(ssa.BlockPlain)
// Allocate starting values
s.labels = map[string]*ssaLabel{}
s.labeledNodes = map[*Node]*ssaLabel{}
s.startmem = s.entryNewValue0(ssa.OpInitMem, ssa.TypeMem)
s.sp = s.entryNewValue0(ssa.OpSP, Types[TUINTPTR]) // TODO: use generic pointer type (unsafe.Pointer?) instead
s.sb = s.entryNewValue0(ssa.OpSB, Types[TUINTPTR])
s.startBlock(s.f.Entry)
s.vars[&memVar] = s.startmem
s.varsyms = map[*Node]interface{}{}
// Generate addresses of local declarations
s.decladdrs = map[*Node]*ssa.Value{}
for _, n := range fn.Func.Dcl {
switch n.Class {
case PPARAM, PPARAMOUT:
aux := s.lookupSymbol(n, &ssa.ArgSymbol{Typ: n.Type, Node: n})
s.decladdrs[n] = s.entryNewValue1A(ssa.OpAddr, Ptrto(n.Type), aux, s.sp)
if n.Class == PPARAMOUT && s.canSSA(n) {
// Save ssa-able PPARAMOUT variables so we can
// store them back to the stack at the end of
// the function.
s.returns = append(s.returns, n)
}
if n.Class == PPARAM && s.canSSA(n) && n.Type.IsPtrShaped() {
s.ptrargs = append(s.ptrargs, n)
n.SetNotLiveAtEnd(true) // SSA takes care of this explicitly
}
case PAUTO:
// processed at each use, to prevent Addr coming
// before the decl.
case PAUTOHEAP:
// moved to heap - already handled by frontend
case PFUNC:
// local function - already handled by frontend
default:
s.Unimplementedf("local variable with class %s unimplemented", classnames[n.Class])
}
}
// Convert the AST-based IR to the SSA-based IR
s.stmts(fn.Func.Enter)
s.stmts(fn.Nbody)
// fallthrough to exit
if s.curBlock != nil {
s.pushLine(fn.Func.Endlineno)
s.exit()
s.popLine()
}
// Check that we used all labels
for name, lab := range s.labels {
if !lab.used() && !lab.reported {
yyerrorl(lab.defNode.Lineno, "label %v defined and not used", name)
lab.reported = true
}
if lab.used() && !lab.defined() && !lab.reported {
yyerrorl(lab.useNode.Lineno, "label %v not defined", name)
lab.reported = true
}
}
// Check any forward gotos. Non-forward gotos have already been checked.
for _, n := range s.fwdGotos {
lab := s.labels[n.Left.Sym.Name]
// If the label is undefined, we have already have printed an error.
if lab.defined() {
s.checkgoto(n, lab.defNode)
}
}
if nerrors > 0 {
s.f.Free()
return nil
}
prelinkNumvars := s.f.NumValues()
sparseDefState := s.locatePotentialPhiFunctions(fn)
// Link up variable uses to variable definitions
s.linkForwardReferences(sparseDefState)
if ssa.BuildStats > 0 {
s.f.LogStat("build", s.f.NumBlocks(), "blocks", prelinkNumvars, "vars_before",
s.f.NumValues(), "vars_after", prelinkNumvars*s.f.NumBlocks(), "ssa_phi_loc_cutoff_score")
}
// Don't carry reference this around longer than necessary
s.exitCode = Nodes{}
// Main call to ssa package to compile function
ssa.Compile(s.f)
return s.f
}
type state struct {
// configuration (arch) information
config *ssa.Config
// function we're building
f *ssa.Func
// labels and labeled control flow nodes (OFOR, OSWITCH, OSELECT) in f
labels map[string]*ssaLabel
labeledNodes map[*Node]*ssaLabel
// gotos that jump forward; required for deferred checkgoto calls
fwdGotos []*Node
// Code that must precede any return
// (e.g., copying value of heap-escaped paramout back to true paramout)
exitCode Nodes
// unlabeled break and continue statement tracking
breakTo *ssa.Block // current target for plain break statement
continueTo *ssa.Block // current target for plain continue statement
// current location where we're interpreting the AST
curBlock *ssa.Block
// variable assignments in the current block (map from variable symbol to ssa value)
// *Node is the unique identifier (an ONAME Node) for the variable.
vars map[*Node]*ssa.Value
// all defined variables at the end of each block. Indexed by block ID.
defvars []map[*Node]*ssa.Value
// addresses of PPARAM and PPARAMOUT variables.
decladdrs map[*Node]*ssa.Value
// symbols for PEXTERN, PAUTO and PPARAMOUT variables so they can be reused.
varsyms map[*Node]interface{}
// starting values. Memory, stack pointer, and globals pointer
startmem *ssa.Value
sp *ssa.Value
sb *ssa.Value
// line number stack. The current line number is top of stack
line []int32
// list of panic calls by function name and line number.
// Used to deduplicate panic calls.
panics map[funcLine]*ssa.Block
// list of FwdRef values.
fwdRefs []*ssa.Value
// list of PPARAMOUT (return) variables.
returns []*Node
// list of PPARAM SSA-able pointer-shaped args. We ensure these are live
// throughout the function to help users avoid premature finalizers.
ptrargs []*Node
cgoUnsafeArgs bool
noWB bool
WBLineno int32 // line number of first write barrier. 0=no write barriers
}
type funcLine struct {
f *Node
line int32
}
type ssaLabel struct {
target *ssa.Block // block identified by this label
breakTarget *ssa.Block // block to break to in control flow node identified by this label
continueTarget *ssa.Block // block to continue to in control flow node identified by this label
defNode *Node // label definition Node (OLABEL)
// Label use Node (OGOTO, OBREAK, OCONTINUE).
// Used only for error detection and reporting.
// There might be multiple uses, but we only need to track one.
useNode *Node
reported bool // reported indicates whether an error has already been reported for this label
}
// defined reports whether the label has a definition (OLABEL node).
func (l *ssaLabel) defined() bool { return l.defNode != nil }
// used reports whether the label has a use (OGOTO, OBREAK, or OCONTINUE node).
func (l *ssaLabel) used() bool { return l.useNode != nil }
// label returns the label associated with sym, creating it if necessary.
func (s *state) label(sym *Sym) *ssaLabel {
lab := s.labels[sym.Name]
if lab == nil {
lab = new(ssaLabel)
s.labels[sym.Name] = lab
}
return lab
}
func (s *state) Logf(msg string, args ...interface{}) { s.config.Logf(msg, args...) }
func (s *state) Log() bool { return s.config.Log() }
func (s *state) Fatalf(msg string, args ...interface{}) { s.config.Fatalf(s.peekLine(), msg, args...) }
func (s *state) Unimplementedf(msg string, args ...interface{}) {
s.config.Unimplementedf(s.peekLine(), msg, args...)
}
func (s *state) Warnl(line int32, msg string, args ...interface{}) { s.config.Warnl(line, msg, args...) }
func (s *state) Debug_checknil() bool { return s.config.Debug_checknil() }
var (
// dummy node for the memory variable
memVar = Node{Op: ONAME, Class: Pxxx, Sym: &Sym{Name: "mem"}}
// dummy nodes for temporary variables
ptrVar = Node{Op: ONAME, Class: Pxxx, Sym: &Sym{Name: "ptr"}}
lenVar = Node{Op: ONAME, Class: Pxxx, Sym: &Sym{Name: "len"}}
newlenVar = Node{Op: ONAME, Class: Pxxx, Sym: &Sym{Name: "newlen"}}
capVar = Node{Op: ONAME, Class: Pxxx, Sym: &Sym{Name: "cap"}}
typVar = Node{Op: ONAME, Class: Pxxx, Sym: &Sym{Name: "typ"}}
idataVar = Node{Op: ONAME, Class: Pxxx, Sym: &Sym{Name: "idata"}}
okVar = Node{Op: ONAME, Class: Pxxx, Sym: &Sym{Name: "ok"}}
deltaVar = Node{Op: ONAME, Class: Pxxx, Sym: &Sym{Name: "delta"}}
)
// startBlock sets the current block we're generating code in to b.
func (s *state) startBlock(b *ssa.Block) {
if s.curBlock != nil {
s.Fatalf("starting block %v when block %v has not ended", b, s.curBlock)
}
s.curBlock = b
s.vars = map[*Node]*ssa.Value{}
}
// endBlock marks the end of generating code for the current block.
// Returns the (former) current block. Returns nil if there is no current
// block, i.e. if no code flows to the current execution point.
func (s *state) endBlock() *ssa.Block {
b := s.curBlock
if b == nil {
return nil
}
for len(s.defvars) <= int(b.ID) {
s.defvars = append(s.defvars, nil)
}
s.defvars[b.ID] = s.vars
s.curBlock = nil
s.vars = nil
b.Line = s.peekLine()
return b
}
// pushLine pushes a line number on the line number stack.
func (s *state) pushLine(line int32) {
if line == 0 {
// the frontend may emit node with line number missing,
// use the parent line number in this case.
line = s.peekLine()
if Debug['K'] != 0 {
Warn("buildssa: line 0")
}
}
s.line = append(s.line, line)
}
// popLine pops the top of the line number stack.
func (s *state) popLine() {
s.line = s.line[:len(s.line)-1]
}
// peekLine peek the top of the line number stack.
func (s *state) peekLine() int32 {
return s.line[len(s.line)-1]
}
func (s *state) Error(msg string, args ...interface{}) {
yyerrorl(s.peekLine(), msg, args...)
}
// newValue0 adds a new value with no arguments to the current block.
func (s *state) newValue0(op ssa.Op, t ssa.Type) *ssa.Value {
return s.curBlock.NewValue0(s.peekLine(), op, t)
}
// newValue0A adds a new value with no arguments and an aux value to the current block.
func (s *state) newValue0A(op ssa.Op, t ssa.Type, aux interface{}) *ssa.Value {
return s.curBlock.NewValue0A(s.peekLine(), op, t, aux)
}
// newValue0I adds a new value with no arguments and an auxint value to the current block.
func (s *state) newValue0I(op ssa.Op, t ssa.Type, auxint int64) *ssa.Value {
return s.curBlock.NewValue0I(s.peekLine(), op, t, auxint)
}
// newValue1 adds a new value with one argument to the current block.
func (s *state) newValue1(op ssa.Op, t ssa.Type, arg *ssa.Value) *ssa.Value {
return s.curBlock.NewValue1(s.peekLine(), op, t, arg)
}
// newValue1A adds a new value with one argument and an aux value to the current block.
func (s *state) newValue1A(op ssa.Op, t ssa.Type, aux interface{}, arg *ssa.Value) *ssa.Value {
return s.curBlock.NewValue1A(s.peekLine(), op, t, aux, arg)
}
// newValue1I adds a new value with one argument and an auxint value to the current block.
func (s *state) newValue1I(op ssa.Op, t ssa.Type, aux int64, arg *ssa.Value) *ssa.Value {
return s.curBlock.NewValue1I(s.peekLine(), op, t, aux, arg)
}
// newValue2 adds a new value with two arguments to the current block.
func (s *state) newValue2(op ssa.Op, t ssa.Type, arg0, arg1 *ssa.Value) *ssa.Value {
return s.curBlock.NewValue2(s.peekLine(), op, t, arg0, arg1)
}
// newValue2I adds a new value with two arguments and an auxint value to the current block.
func (s *state) newValue2I(op ssa.Op, t ssa.Type, aux int64, arg0, arg1 *ssa.Value) *ssa.Value {
return s.curBlock.NewValue2I(s.peekLine(), op, t, aux, arg0, arg1)
}
// newValue3 adds a new value with three arguments to the current block.
func (s *state) newValue3(op ssa.Op, t ssa.Type, arg0, arg1, arg2 *ssa.Value) *ssa.Value {
return s.curBlock.NewValue3(s.peekLine(), op, t, arg0, arg1, arg2)
}
// newValue3I adds a new value with three arguments and an auxint value to the current block.
func (s *state) newValue3I(op ssa.Op, t ssa.Type, aux int64, arg0, arg1, arg2 *ssa.Value) *ssa.Value {
return s.curBlock.NewValue3I(s.peekLine(), op, t, aux, arg0, arg1, arg2)
}
// entryNewValue0 adds a new value with no arguments to the entry block.
func (s *state) entryNewValue0(op ssa.Op, t ssa.Type) *ssa.Value {
return s.f.Entry.NewValue0(s.peekLine(), op, t)
}
// entryNewValue0A adds a new value with no arguments and an aux value to the entry block.
func (s *state) entryNewValue0A(op ssa.Op, t ssa.Type, aux interface{}) *ssa.Value {
return s.f.Entry.NewValue0A(s.peekLine(), op, t, aux)
}
// entryNewValue0I adds a new value with no arguments and an auxint value to the entry block.
func (s *state) entryNewValue0I(op ssa.Op, t ssa.Type, auxint int64) *ssa.Value {
return s.f.Entry.NewValue0I(s.peekLine(), op, t, auxint)
}
// entryNewValue1 adds a new value with one argument to the entry block.
func (s *state) entryNewValue1(op ssa.Op, t ssa.Type, arg *ssa.Value) *ssa.Value {
return s.f.Entry.NewValue1(s.peekLine(), op, t, arg)
}
// entryNewValue1 adds a new value with one argument and an auxint value to the entry block.
func (s *state) entryNewValue1I(op ssa.Op, t ssa.Type, auxint int64, arg *ssa.Value) *ssa.Value {
return s.f.Entry.NewValue1I(s.peekLine(), op, t, auxint, arg)
}
// entryNewValue1A adds a new value with one argument and an aux value to the entry block.
func (s *state) entryNewValue1A(op ssa.Op, t ssa.Type, aux interface{}, arg *ssa.Value) *ssa.Value {
return s.f.Entry.NewValue1A(s.peekLine(), op, t, aux, arg)
}
// entryNewValue2 adds a new value with two arguments to the entry block.
func (s *state) entryNewValue2(op ssa.Op, t ssa.Type, arg0, arg1 *ssa.Value) *ssa.Value {
return s.f.Entry.NewValue2(s.peekLine(), op, t, arg0, arg1)
}
// const* routines add a new const value to the entry block.
func (s *state) constSlice(t ssa.Type) *ssa.Value { return s.f.ConstSlice(s.peekLine(), t) }
func (s *state) constInterface(t ssa.Type) *ssa.Value { return s.f.ConstInterface(s.peekLine(), t) }
func (s *state) constNil(t ssa.Type) *ssa.Value { return s.f.ConstNil(s.peekLine(), t) }
func (s *state) constEmptyString(t ssa.Type) *ssa.Value { return s.f.ConstEmptyString(s.peekLine(), t) }
func (s *state) constBool(c bool) *ssa.Value {
return s.f.ConstBool(s.peekLine(), Types[TBOOL], c)
}
func (s *state) constInt8(t ssa.Type, c int8) *ssa.Value {
return s.f.ConstInt8(s.peekLine(), t, c)
}
func (s *state) constInt16(t ssa.Type, c int16) *ssa.Value {
return s.f.ConstInt16(s.peekLine(), t, c)
}
func (s *state) constInt32(t ssa.Type, c int32) *ssa.Value {
return s.f.ConstInt32(s.peekLine(), t, c)
}
func (s *state) constInt64(t ssa.Type, c int64) *ssa.Value {
return s.f.ConstInt64(s.peekLine(), t, c)
}
func (s *state) constFloat32(t ssa.Type, c float64) *ssa.Value {
return s.f.ConstFloat32(s.peekLine(), t, c)
}
func (s *state) constFloat64(t ssa.Type, c float64) *ssa.Value {
return s.f.ConstFloat64(s.peekLine(), t, c)
}
func (s *state) constInt(t ssa.Type, c int64) *ssa.Value {
if s.config.IntSize == 8 {
return s.constInt64(t, c)
}
if int64(int32(c)) != c {
s.Fatalf("integer constant too big %d", c)
}
return s.constInt32(t, int32(c))
}
func (s *state) stmts(a Nodes) {
for _, x := range a.Slice() {
s.stmt(x)
}
}
// ssaStmtList converts the statement n to SSA and adds it to s.
func (s *state) stmtList(l Nodes) {
for _, n := range l.Slice() {
s.stmt(n)
}
}
// ssaStmt converts the statement n to SSA and adds it to s.
func (s *state) stmt(n *Node) {
s.pushLine(n.Lineno)
defer s.popLine()
// If s.curBlock is nil, then we're about to generate dead code.
// We can't just short-circuit here, though,
// because we check labels and gotos as part of SSA generation.
// Provide a block for the dead code so that we don't have
// to add special cases everywhere else.
if s.curBlock == nil {
dead := s.f.NewBlock(ssa.BlockPlain)
s.startBlock(dead)
}
s.stmtList(n.Ninit)
switch n.Op {
case OBLOCK:
s.stmtList(n.List)
// No-ops
case OEMPTY, ODCLCONST, ODCLTYPE, OFALL:
// Expression statements
case OCALLFUNC, OCALLMETH, OCALLINTER:
s.call(n, callNormal)
if n.Op == OCALLFUNC && n.Left.Op == ONAME && n.Left.Class == PFUNC &&
(compiling_runtime && n.Left.Sym.Name == "throw" ||
n.Left.Sym.Pkg == Runtimepkg && (n.Left.Sym.Name == "gopanic" || n.Left.Sym.Name == "selectgo" || n.Left.Sym.Name == "block")) {
m := s.mem()
b := s.endBlock()
b.Kind = ssa.BlockExit
b.SetControl(m)
// TODO: never rewrite OPANIC to OCALLFUNC in the
// first place. Need to wait until all backends
// go through SSA.
}
case ODEFER:
s.call(n.Left, callDefer)
case OPROC:
s.call(n.Left, callGo)
case OAS2DOTTYPE:
res, resok := s.dottype(n.Rlist.First(), true)
s.assign(n.List.First(), res, needwritebarrier(n.List.First(), n.Rlist.First()), false, n.Lineno, 0, false)
s.assign(n.List.Second(), resok, false, false, n.Lineno, 0, false)
return
case ODCL:
if n.Left.Class == PAUTOHEAP {
Fatalf("DCL %v", n)
}
case OLABEL:
sym := n.Left.Sym
if isblanksym(sym) {
// Empty identifier is valid but useless.
// See issues 11589, 11593.
return
}
lab := s.label(sym)
// Associate label with its control flow node, if any
if ctl := n.Name.Defn; ctl != nil {
switch ctl.Op {
case OFOR, OSWITCH, OSELECT:
s.labeledNodes[ctl] = lab
}
}
if !lab.defined() {
lab.defNode = n
} else {
s.Error("label %v already defined at %v", sym, linestr(lab.defNode.Lineno))
lab.reported = true
}
// The label might already have a target block via a goto.
if lab.target == nil {
lab.target = s.f.NewBlock(ssa.BlockPlain)
}
// go to that label (we pretend "label:" is preceded by "goto label")
b := s.endBlock()
b.AddEdgeTo(lab.target)
s.startBlock(lab.target)
case OGOTO:
sym := n.Left.Sym
lab := s.label(sym)
if lab.target == nil {
lab.target = s.f.NewBlock(ssa.BlockPlain)
}
if !lab.used() {
lab.useNode = n
}
if lab.defined() {
s.checkgoto(n, lab.defNode)
} else {
s.fwdGotos = append(s.fwdGotos, n)
}
b := s.endBlock()
b.AddEdgeTo(lab.target)
case OAS, OASWB:
// Check whether we can generate static data rather than code.
// If so, ignore n and defer data generation until codegen.
// Failure to do this causes writes to readonly symbols.
if gen_as_init(n, true) {
var data []*Node
if s.f.StaticData != nil {
data = s.f.StaticData.([]*Node)
}
s.f.StaticData = append(data, n)
return
}
if n.Left == n.Right && n.Left.Op == ONAME {
// An x=x assignment. No point in doing anything
// here. In addition, skipping this assignment
// prevents generating:
// VARDEF x
// COPY x -> x
// which is bad because x is incorrectly considered
// dead before the vardef. See issue #14904.
return
}
var t *Type
if n.Right != nil {
t = n.Right.Type
} else {
t = n.Left.Type
}
// Evaluate RHS.
rhs := n.Right
if rhs != nil {
switch rhs.Op {
case OSTRUCTLIT, OARRAYLIT:
// All literals with nonzero fields have already been
// rewritten during walk. Any that remain are just T{}
// or equivalents. Use the zero value.
if !iszero(rhs) {
Fatalf("literal with nonzero value in SSA: %v", rhs)
}
rhs = nil
case OAPPEND:
// If we're writing the result of an append back to the same slice,
// handle it specially to avoid write barriers on the fast (non-growth) path.
// If the slice can be SSA'd, it'll be on the stack,
// so there will be no write barriers,
// so there's no need to attempt to prevent them.
if samesafeexpr(n.Left, rhs.List.First()) && !s.canSSA(n.Left) {
s.append(rhs, true)
return
}
}
}
var r *ssa.Value
var isVolatile bool
needwb := n.Op == OASWB && rhs != nil
deref := !canSSAType(t)
if deref {
if rhs == nil {
r = nil // Signal assign to use OpZero.
} else {
r, isVolatile = s.addr(rhs, false)
}
} else {
if rhs == nil {
r = s.zeroVal(t)
} else {
r = s.expr(rhs)
}
}
if rhs != nil && rhs.Op == OAPPEND {
// The frontend gets rid of the write barrier to enable the special OAPPEND
// handling above, but since this is not a special case, we need it.
// TODO: just add a ptr graying to the end of growslice?
// TODO: check whether we need to provide special handling and a write barrier
// for ODOTTYPE and ORECV also.
// They get similar wb-removal treatment in walk.go:OAS.
needwb = true
}
var skip skipMask
if rhs != nil && (rhs.Op == OSLICE || rhs.Op == OSLICE3 || rhs.Op == OSLICESTR) && samesafeexpr(rhs.Left, n.Left) {
// We're assigning a slicing operation back to its source.
// Don't write back fields we aren't changing. See issue #14855.
i, j, k := rhs.SliceBounds()
if i != nil && (i.Op == OLITERAL && i.Val().Ctype() == CTINT && i.Int64() == 0) {
// [0:...] is the same as [:...]
i = nil
}
// TODO: detect defaults for len/cap also.
// Currently doesn't really work because (*p)[:len(*p)] appears here as:
// tmp = len(*p)
// (*p)[:tmp]
//if j != nil && (j.Op == OLEN && samesafeexpr(j.Left, n.Left)) {
// j = nil
//}
//if k != nil && (k.Op == OCAP && samesafeexpr(k.Left, n.Left)) {
// k = nil
//}
if i == nil {
skip |= skipPtr
if j == nil {
skip |= skipLen
}
if k == nil {
skip |= skipCap
}
}
}
s.assign(n.Left, r, needwb, deref, n.Lineno, skip, isVolatile)
case OIF:
bThen := s.f.NewBlock(ssa.BlockPlain)
bEnd := s.f.NewBlock(ssa.BlockPlain)
var bElse *ssa.Block
if n.Rlist.Len() != 0 {
bElse = s.f.NewBlock(ssa.BlockPlain)
s.condBranch(n.Left, bThen, bElse, n.Likely)
} else {
s.condBranch(n.Left, bThen, bEnd, n.Likely)
}
s.startBlock(bThen)
s.stmts(n.Nbody)
if b := s.endBlock(); b != nil {
b.AddEdgeTo(bEnd)
}
if n.Rlist.Len() != 0 {
s.startBlock(bElse)
s.stmtList(n.Rlist)
if b := s.endBlock(); b != nil {
b.AddEdgeTo(bEnd)
}
}
s.startBlock(bEnd)
case ORETURN:
s.stmtList(n.List)
s.exit()
case ORETJMP:
s.stmtList(n.List)
b := s.exit()
b.Kind = ssa.BlockRetJmp // override BlockRet
b.Aux = n.Left.Sym
case OCONTINUE, OBREAK:
var op string
var to *ssa.Block
switch n.Op {
case OCONTINUE:
op = "continue"
to = s.continueTo
case OBREAK:
op = "break"
to = s.breakTo
}
if n.Left == nil {
// plain break/continue
if to == nil {
s.Error("%s is not in a loop", op)
return
}
// nothing to do; "to" is already the correct target
} else {
// labeled break/continue; look up the target
sym := n.Left.Sym
lab := s.label(sym)
if !lab.used() {
lab.useNode = n.Left
}
if !lab.defined() {
s.Error("%s label not defined: %v", op, sym)
lab.reported = true
return
}
switch n.Op {
case OCONTINUE:
to = lab.continueTarget
case OBREAK:
to = lab.breakTarget
}
if to == nil {
// Valid label but not usable with a break/continue here, e.g.:
// for {
// continue abc
// }
// abc:
// for {}
s.Error("invalid %s label %v", op, sym)
lab.reported = true
return
}
}
b := s.endBlock()
b.AddEdgeTo(to)
case OFOR:
// OFOR: for Ninit; Left; Right { Nbody }
bCond := s.f.NewBlock(ssa.BlockPlain)
bBody := s.f.NewBlock(ssa.BlockPlain)
bIncr := s.f.NewBlock(ssa.BlockPlain)
bEnd := s.f.NewBlock(ssa.BlockPlain)
// first, jump to condition test
b := s.endBlock()
b.AddEdgeTo(bCond)
// generate code to test condition
s.startBlock(bCond)
if n.Left != nil {
s.condBranch(n.Left, bBody, bEnd, 1)
} else {
b := s.endBlock()
b.Kind = ssa.BlockPlain
b.AddEdgeTo(bBody)
}
// set up for continue/break in body
prevContinue := s.continueTo
prevBreak := s.breakTo
s.continueTo = bIncr
s.breakTo = bEnd
lab := s.labeledNodes[n]
if lab != nil {
// labeled for loop
lab.continueTarget = bIncr
lab.breakTarget = bEnd
}
// generate body
s.startBlock(bBody)
s.stmts(n.Nbody)
// tear down continue/break
s.continueTo = prevContinue
s.breakTo = prevBreak
if lab != nil {
lab.continueTarget = nil
lab.breakTarget = nil
}
// done with body, goto incr
if b := s.endBlock(); b != nil {
b.AddEdgeTo(bIncr)
}
// generate incr
s.startBlock(bIncr)
if n.Right != nil {
s.stmt(n.Right)
}
if b := s.endBlock(); b != nil {
b.AddEdgeTo(bCond)
}
s.startBlock(bEnd)
case OSWITCH, OSELECT:
// These have been mostly rewritten by the front end into their Nbody fields.
// Our main task is to correctly hook up any break statements.
bEnd := s.f.NewBlock(ssa.BlockPlain)
prevBreak := s.breakTo
s.breakTo = bEnd
lab := s.labeledNodes[n]
if lab != nil {
// labeled
lab.breakTarget = bEnd
}
// generate body code
s.stmts(n.Nbody)
s.breakTo = prevBreak
if lab != nil {
lab.breakTarget = nil
}
// OSWITCH never falls through (s.curBlock == nil here).
// OSELECT does not fall through if we're calling selectgo.
// OSELECT does fall through if we're calling selectnb{send,recv}[2].
// In those latter cases, go to the code after the select.
if b := s.endBlock(); b != nil {
b.AddEdgeTo(bEnd)
}
s.startBlock(bEnd)
case OVARKILL:
// Insert a varkill op to record that a variable is no longer live.
// We only care about liveness info at call sites, so putting the
// varkill in the store chain is enough to keep it correctly ordered
// with respect to call ops.
if !s.canSSA(n.Left) {
s.vars[&memVar] = s.newValue1A(ssa.OpVarKill, ssa.TypeMem, n.Left, s.mem())
}
case OVARLIVE:
// Insert a varlive op to record that a variable is still live.
if !n.Left.Addrtaken {
s.Fatalf("VARLIVE variable %s must have Addrtaken set", n.Left)
}
s.vars[&memVar] = s.newValue1A(ssa.OpVarLive, ssa.TypeMem, n.Left, s.mem())
case OCHECKNIL:
p := s.expr(n.Left)
s.nilCheck(p)
default:
s.Unimplementedf("unhandled stmt %s", n.Op)
}
}
// exit processes any code that needs to be generated just before returning.
// It returns a BlockRet block that ends the control flow. Its control value
// will be set to the final memory state.
func (s *state) exit() *ssa.Block {
if hasdefer {
s.rtcall(Deferreturn, true, nil)
}
// Run exit code. Typically, this code copies heap-allocated PPARAMOUT
// variables back to the stack.
s.stmts(s.exitCode)
// Store SSAable PPARAMOUT variables back to stack locations.
for _, n := range s.returns {
addr := s.decladdrs[n]
val := s.variable(n, n.Type)
s.vars[&memVar] = s.newValue1A(ssa.OpVarDef, ssa.TypeMem, n, s.mem())
s.vars[&memVar] = s.newValue3I(ssa.OpStore, ssa.TypeMem, n.Type.Size(), addr, val, s.mem())
// TODO: if val is ever spilled, we'd like to use the
// PPARAMOUT slot for spilling it. That won't happen
// currently.
}
// Keep input pointer args live until the return. This is a bandaid
// fix for 1.7 for what will become in 1.8 explicit runtime.KeepAlive calls.
// For <= 1.7 we guarantee that pointer input arguments live to the end of
// the function to prevent premature (from the user's point of view)
// execution of finalizers. See issue 15277.
// TODO: remove for 1.8?
for _, n := range s.ptrargs {
s.vars[&memVar] = s.newValue2(ssa.OpKeepAlive, ssa.TypeMem, s.variable(n, n.Type), s.mem())
}
// Do actual return.
m := s.mem()
b := s.endBlock()
b.Kind = ssa.BlockRet
b.SetControl(m)
return b
}
type opAndType struct {
op Op
etype EType
}
var opToSSA = map[opAndType]ssa.Op{
opAndType{OADD, TINT8}: ssa.OpAdd8,
opAndType{OADD, TUINT8}: ssa.OpAdd8,
opAndType{OADD, TINT16}: ssa.OpAdd16,
opAndType{OADD, TUINT16}: ssa.OpAdd16,
opAndType{OADD, TINT32}: ssa.OpAdd32,
opAndType{OADD, TUINT32}: ssa.OpAdd32,
opAndType{OADD, TPTR32}: ssa.OpAdd32,
opAndType{OADD, TINT64}: ssa.OpAdd64,
opAndType{OADD, TUINT64}: ssa.OpAdd64,
opAndType{OADD, TPTR64}: ssa.OpAdd64,
opAndType{OADD, TFLOAT32}: ssa.OpAdd32F,
opAndType{OADD, TFLOAT64}: ssa.OpAdd64F,
opAndType{OSUB, TINT8}: ssa.OpSub8,
opAndType{OSUB, TUINT8}: ssa.OpSub8,
opAndType{OSUB, TINT16}: ssa.OpSub16,
opAndType{OSUB, TUINT16}: ssa.OpSub16,
opAndType{OSUB, TINT32}: ssa.OpSub32,
opAndType{OSUB, TUINT32}: ssa.OpSub32,
opAndType{OSUB, TINT64}: ssa.OpSub64,
opAndType{OSUB, TUINT64}: ssa.OpSub64,
opAndType{OSUB, TFLOAT32}: ssa.OpSub32F,
opAndType{OSUB, TFLOAT64}: ssa.OpSub64F,
opAndType{ONOT, TBOOL}: ssa.OpNot,
opAndType{OMINUS, TINT8}: ssa.OpNeg8,
opAndType{OMINUS, TUINT8}: ssa.OpNeg8,
opAndType{OMINUS, TINT16}: ssa.OpNeg16,
opAndType{OMINUS, TUINT16}: ssa.OpNeg16,
opAndType{OMINUS, TINT32}: ssa.OpNeg32,
opAndType{OMINUS, TUINT32}: ssa.OpNeg32,
opAndType{OMINUS, TINT64}: ssa.OpNeg64,
opAndType{OMINUS, TUINT64}: ssa.OpNeg64,
opAndType{OMINUS, TFLOAT32}: ssa.OpNeg32F,
opAndType{OMINUS, TFLOAT64}: ssa.OpNeg64F,
opAndType{OCOM, TINT8}: ssa.OpCom8,
opAndType{OCOM, TUINT8}: ssa.OpCom8,
opAndType{OCOM, TINT16}: ssa.OpCom16,
opAndType{OCOM, TUINT16}: ssa.OpCom16,
opAndType{OCOM, TINT32}: ssa.OpCom32,
opAndType{OCOM, TUINT32}: ssa.OpCom32,
opAndType{OCOM, TINT64}: ssa.OpCom64,
opAndType{OCOM, TUINT64}: ssa.OpCom64,
opAndType{OIMAG, TCOMPLEX64}: ssa.OpComplexImag,
opAndType{OIMAG, TCOMPLEX128}: ssa.OpComplexImag,
opAndType{OREAL, TCOMPLEX64}: ssa.OpComplexReal,
opAndType{OREAL, TCOMPLEX128}: ssa.OpComplexReal,
opAndType{OMUL, TINT8}: ssa.OpMul8,
opAndType{OMUL, TUINT8}: ssa.OpMul8,
opAndType{OMUL, TINT16}: ssa.OpMul16,
opAndType{OMUL, TUINT16}: ssa.OpMul16,
opAndType{OMUL, TINT32}: ssa.OpMul32,
opAndType{OMUL, TUINT32}: ssa.OpMul32,
opAndType{OMUL, TINT64}: ssa.OpMul64,
opAndType{OMUL, TUINT64}: ssa.OpMul64,
opAndType{OMUL, TFLOAT32}: ssa.OpMul32F,
opAndType{OMUL, TFLOAT64}: ssa.OpMul64F,
opAndType{ODIV, TFLOAT32}: ssa.OpDiv32F,
opAndType{ODIV, TFLOAT64}: ssa.OpDiv64F,
opAndType{OHMUL, TINT8}: ssa.OpHmul8,
opAndType{OHMUL, TUINT8}: ssa.OpHmul8u,
opAndType{OHMUL, TINT16}: ssa.OpHmul16,
opAndType{OHMUL, TUINT16}: ssa.OpHmul16u,
opAndType{OHMUL, TINT32}: ssa.OpHmul32,
opAndType{OHMUL, TUINT32}: ssa.OpHmul32u,
opAndType{ODIV, TINT8}: ssa.OpDiv8,
opAndType{ODIV, TUINT8}: ssa.OpDiv8u,
opAndType{ODIV, TINT16}: ssa.OpDiv16,
opAndType{ODIV, TUINT16}: ssa.OpDiv16u,
opAndType{ODIV, TINT32}: ssa.OpDiv32,
opAndType{ODIV, TUINT32}: ssa.OpDiv32u,
opAndType{ODIV, TINT64}: ssa.OpDiv64,
opAndType{ODIV, TUINT64}: ssa.OpDiv64u,
opAndType{OMOD, TINT8}: ssa.OpMod8,
opAndType{OMOD, TUINT8}: ssa.OpMod8u,
opAndType{OMOD, TINT16}: ssa.OpMod16,
opAndType{OMOD, TUINT16}: ssa.OpMod16u,
opAndType{OMOD, TINT32}: ssa.OpMod32,
opAndType{OMOD, TUINT32}: ssa.OpMod32u,
opAndType{OMOD, TINT64}: ssa.OpMod64,
opAndType{OMOD, TUINT64}: ssa.OpMod64u,
opAndType{OAND, TINT8}: ssa.OpAnd8,
opAndType{OAND, TUINT8}: ssa.OpAnd8,
opAndType{OAND, TINT16}: ssa.OpAnd16,
opAndType{OAND, TUINT16}: ssa.OpAnd16,
opAndType{OAND, TINT32}: ssa.OpAnd32,
opAndType{OAND, TUINT32}: ssa.OpAnd32,
opAndType{OAND, TINT64}: ssa.OpAnd64,
opAndType{OAND, TUINT64}: ssa.OpAnd64,
opAndType{OOR, TINT8}: ssa.OpOr8,
opAndType{OOR, TUINT8}: ssa.OpOr8,
opAndType{OOR, TINT16}: ssa.OpOr16,
opAndType{OOR, TUINT16}: ssa.OpOr16,
opAndType{OOR, TINT32}: ssa.OpOr32,
opAndType{OOR, TUINT32}: ssa.OpOr32,
opAndType{OOR, TINT64}: ssa.OpOr64,
opAndType{OOR, TUINT64}: ssa.OpOr64,
opAndType{OXOR, TINT8}: ssa.OpXor8,
opAndType{OXOR, TUINT8}: ssa.OpXor8,
opAndType{OXOR, TINT16}: ssa.OpXor16,
opAndType{OXOR, TUINT16}: ssa.OpXor16,
opAndType{OXOR, TINT32}: ssa.OpXor32,
opAndType{OXOR, TUINT32}: ssa.OpXor32,
opAndType{OXOR, TINT64}: ssa.OpXor64,
opAndType{OXOR, TUINT64}: ssa.OpXor64,
opAndType{OEQ, TBOOL}: ssa.OpEqB,
opAndType{OEQ, TINT8}: ssa.OpEq8,
opAndType{OEQ, TUINT8}: ssa.OpEq8,
opAndType{OEQ, TINT16}: ssa.OpEq16,
opAndType{OEQ, TUINT16}: ssa.OpEq16,
opAndType{OEQ, TINT32}: ssa.OpEq32,
opAndType{OEQ, TUINT32}: ssa.OpEq32,
opAndType{OEQ, TINT64}: ssa.OpEq64,
opAndType{OEQ, TUINT64}: ssa.OpEq64,
opAndType{OEQ, TINTER}: ssa.OpEqInter,
opAndType{OEQ, TSLICE}: ssa.OpEqSlice,
opAndType{OEQ, TFUNC}: ssa.OpEqPtr,
opAndType{OEQ, TMAP}: ssa.OpEqPtr,
opAndType{OEQ, TCHAN}: ssa.OpEqPtr,
opAndType{OEQ, TPTR32}: ssa.OpEqPtr,
opAndType{OEQ, TPTR64}: ssa.OpEqPtr,
opAndType{OEQ, TUINTPTR}: ssa.OpEqPtr,
opAndType{OEQ, TUNSAFEPTR}: ssa.OpEqPtr,
opAndType{OEQ, TFLOAT64}: ssa.OpEq64F,
opAndType{OEQ, TFLOAT32}: ssa.OpEq32F,
opAndType{ONE, TBOOL}: ssa.OpNeqB,
opAndType{ONE, TINT8}: ssa.OpNeq8,
opAndType{ONE, TUINT8}: ssa.OpNeq8,
opAndType{ONE, TINT16}: ssa.OpNeq16,
opAndType{ONE, TUINT16}: ssa.OpNeq16,
opAndType{ONE, TINT32}: ssa.OpNeq32,
opAndType{ONE, TUINT32}: ssa.OpNeq32,
opAndType{ONE, TINT64}: ssa.OpNeq64,
opAndType{ONE, TUINT64}: ssa.OpNeq64,
opAndType{ONE, TINTER}: ssa.OpNeqInter,
opAndType{ONE, TSLICE}: ssa.OpNeqSlice,
opAndType{ONE, TFUNC}: ssa.OpNeqPtr,
opAndType{ONE, TMAP}: ssa.OpNeqPtr,
opAndType{ONE, TCHAN}: ssa.OpNeqPtr,
opAndType{ONE, TPTR32}: ssa.OpNeqPtr,
opAndType{ONE, TPTR64}: ssa.OpNeqPtr,
opAndType{ONE, TUINTPTR}: ssa.OpNeqPtr,
opAndType{ONE, TUNSAFEPTR}: ssa.OpNeqPtr,
opAndType{ONE, TFLOAT64}: ssa.OpNeq64F,
opAndType{ONE, TFLOAT32}: ssa.OpNeq32F,
opAndType{OLT, TINT8}: ssa.OpLess8,
opAndType{OLT, TUINT8}: ssa.OpLess8U,
opAndType{OLT, TINT16}: ssa.OpLess16,
opAndType{OLT, TUINT16}: ssa.OpLess16U,
opAndType{OLT, TINT32}: ssa.OpLess32,
opAndType{OLT, TUINT32}: ssa.OpLess32U,
opAndType{OLT, TINT64}: ssa.OpLess64,
opAndType{OLT, TUINT64}: ssa.OpLess64U,
opAndType{OLT, TFLOAT64}: ssa.OpLess64F,
opAndType{OLT, TFLOAT32}: ssa.OpLess32F,
opAndType{OGT, TINT8}: ssa.OpGreater8,
opAndType{OGT, TUINT8}: ssa.OpGreater8U,
opAndType{OGT, TINT16}: ssa.OpGreater16,
opAndType{OGT, TUINT16}: ssa.OpGreater16U,
opAndType{OGT, TINT32}: ssa.OpGreater32,
opAndType{OGT, TUINT32}: ssa.OpGreater32U,
opAndType{OGT, TINT64}: ssa.OpGreater64,
opAndType{OGT, TUINT64}: ssa.OpGreater64U,
opAndType{OGT, TFLOAT64}: ssa.OpGreater64F,
opAndType{OGT, TFLOAT32}: ssa.OpGreater32F,
opAndType{OLE, TINT8}: ssa.OpLeq8,
opAndType{OLE, TUINT8}: ssa.OpLeq8U,
opAndType{OLE, TINT16}: ssa.OpLeq16,
opAndType{OLE, TUINT16}: ssa.OpLeq16U,
opAndType{OLE, TINT32}: ssa.OpLeq32,
opAndType{OLE, TUINT32}: ssa.OpLeq32U,
opAndType{OLE, TINT64}: ssa.OpLeq64,
opAndType{OLE, TUINT64}: ssa.OpLeq64U,
opAndType{OLE, TFLOAT64}: ssa.OpLeq64F,
opAndType{OLE, TFLOAT32}: ssa.OpLeq32F,
opAndType{OGE, TINT8}: ssa.OpGeq8,
opAndType{OGE, TUINT8}: ssa.OpGeq8U,
opAndType{OGE, TINT16}: ssa.OpGeq16,
opAndType{OGE, TUINT16}: ssa.OpGeq16U,
opAndType{OGE, TINT32}: ssa.OpGeq32,
opAndType{OGE, TUINT32}: ssa.OpGeq32U,
opAndType{OGE, TINT64}: ssa.OpGeq64,
opAndType{OGE, TUINT64}: ssa.OpGeq64U,
opAndType{OGE, TFLOAT64}: ssa.OpGeq64F,
opAndType{OGE, TFLOAT32}: ssa.OpGeq32F,
opAndType{OLROT, TUINT8}: ssa.OpLrot8,
opAndType{OLROT, TUINT16}: ssa.OpLrot16,
opAndType{OLROT, TUINT32}: ssa.OpLrot32,
opAndType{OLROT, TUINT64}: ssa.OpLrot64,
opAndType{OSQRT, TFLOAT64}: ssa.OpSqrt,
}
func (s *state) concreteEtype(t *Type) EType {
e := t.Etype
switch e {
default:
return e
case TINT:
if s.config.IntSize == 8 {
return TINT64
}
return TINT32
case TUINT:
if s.config.IntSize == 8 {
return TUINT64
}
return TUINT32
case TUINTPTR:
if s.config.PtrSize == 8 {
return TUINT64
}
return TUINT32
}
}
func (s *state) ssaOp(op Op, t *Type) ssa.Op {
etype := s.concreteEtype(t)
x, ok := opToSSA[opAndType{op, etype}]
if !ok {
s.Unimplementedf("unhandled binary op %s %s", op, etype)
}
return x
}
func floatForComplex(t *Type) *Type {
if t.Size() == 8 {
return Types[TFLOAT32]
} else {
return Types[TFLOAT64]
}
}
type opAndTwoTypes struct {
op Op
etype1 EType
etype2 EType
}
type twoTypes struct {
etype1 EType
etype2 EType
}
type twoOpsAndType struct {
op1 ssa.Op
op2 ssa.Op
intermediateType EType
}
var fpConvOpToSSA = map[twoTypes]twoOpsAndType{
twoTypes{TINT8, TFLOAT32}: twoOpsAndType{ssa.OpSignExt8to32, ssa.OpCvt32to32F, TINT32},
twoTypes{TINT16, TFLOAT32}: twoOpsAndType{ssa.OpSignExt16to32, ssa.OpCvt32to32F, TINT32},
twoTypes{TINT32, TFLOAT32}: twoOpsAndType{ssa.OpCopy, ssa.OpCvt32to32F, TINT32},
twoTypes{TINT64, TFLOAT32}: twoOpsAndType{ssa.OpCopy, ssa.OpCvt64to32F, TINT64},
twoTypes{TINT8, TFLOAT64}: twoOpsAndType{ssa.OpSignExt8to32, ssa.OpCvt32to64F, TINT32},
twoTypes{TINT16, TFLOAT64}: twoOpsAndType{ssa.OpSignExt16to32, ssa.OpCvt32to64F, TINT32},
twoTypes{TINT32, TFLOAT64}: twoOpsAndType{ssa.OpCopy, ssa.OpCvt32to64F, TINT32},
twoTypes{TINT64, TFLOAT64}: twoOpsAndType{ssa.OpCopy, ssa.OpCvt64to64F, TINT64},
twoTypes{TFLOAT32, TINT8}: twoOpsAndType{ssa.OpCvt32Fto32, ssa.OpTrunc32to8, TINT32},
twoTypes{TFLOAT32, TINT16}: twoOpsAndType{ssa.OpCvt32Fto32, ssa.OpTrunc32to16, TINT32},
twoTypes{TFLOAT32, TINT32}: twoOpsAndType{ssa.OpCvt32Fto32, ssa.OpCopy, TINT32},
twoTypes{TFLOAT32, TINT64}: twoOpsAndType{ssa.OpCvt32Fto64, ssa.OpCopy, TINT64},
twoTypes{TFLOAT64, TINT8}: twoOpsAndType{ssa.OpCvt64Fto32, ssa.OpTrunc32to8, TINT32},
twoTypes{TFLOAT64, TINT16}: twoOpsAndType{ssa.OpCvt64Fto32, ssa.OpTrunc32to16, TINT32},
twoTypes{TFLOAT64, TINT32}: twoOpsAndType{ssa.OpCvt64Fto32, ssa.OpCopy, TINT32},
twoTypes{TFLOAT64, TINT64}: twoOpsAndType{ssa.OpCvt64Fto64, ssa.OpCopy, TINT64},
// unsigned
twoTypes{TUINT8, TFLOAT32}: twoOpsAndType{ssa.OpZeroExt8to32, ssa.OpCvt32to32F, TINT32},
twoTypes{TUINT16, TFLOAT32}: twoOpsAndType{ssa.OpZeroExt16to32, ssa.OpCvt32to32F, TINT32},
twoTypes{TUINT32, TFLOAT32}: twoOpsAndType{ssa.OpZeroExt32to64, ssa.OpCvt64to32F, TINT64}, // go wide to dodge unsigned
twoTypes{TUINT64, TFLOAT32}: twoOpsAndType{ssa.OpCopy, ssa.OpInvalid, TUINT64}, // Cvt64Uto32F, branchy code expansion instead
twoTypes{TUINT8, TFLOAT64}: twoOpsAndType{ssa.OpZeroExt8to32, ssa.OpCvt32to64F, TINT32},
twoTypes{TUINT16, TFLOAT64}: twoOpsAndType{ssa.OpZeroExt16to32, ssa.OpCvt32to64F, TINT32},
twoTypes{TUINT32, TFLOAT64}: twoOpsAndType{ssa.OpZeroExt32to64, ssa.OpCvt64to64F, TINT64}, // go wide to dodge unsigned
twoTypes{TUINT64, TFLOAT64}: twoOpsAndType{ssa.OpCopy, ssa.OpInvalid, TUINT64}, // Cvt64Uto64F, branchy code expansion instead
twoTypes{TFLOAT32, TUINT8}: twoOpsAndType{ssa.OpCvt32Fto32, ssa.OpTrunc32to8, TINT32},
twoTypes{TFLOAT32, TUINT16}: twoOpsAndType{ssa.OpCvt32Fto32, ssa.OpTrunc32to16, TINT32},
twoTypes{TFLOAT32, TUINT32}: twoOpsAndType{ssa.OpCvt32Fto64, ssa.OpTrunc64to32, TINT64}, // go wide to dodge unsigned
twoTypes{TFLOAT32, TUINT64}: twoOpsAndType{ssa.OpInvalid, ssa.OpCopy, TUINT64}, // Cvt32Fto64U, branchy code expansion instead
twoTypes{TFLOAT64, TUINT8}: twoOpsAndType{ssa.OpCvt64Fto32, ssa.OpTrunc32to8, TINT32},
twoTypes{TFLOAT64, TUINT16}: twoOpsAndType{ssa.OpCvt64Fto32, ssa.OpTrunc32to16, TINT32},
twoTypes{TFLOAT64, TUINT32}: twoOpsAndType{ssa.OpCvt64Fto64, ssa.OpTrunc64to32, TINT64}, // go wide to dodge unsigned
twoTypes{TFLOAT64, TUINT64}: twoOpsAndType{ssa.OpInvalid, ssa.OpCopy, TUINT64}, // Cvt64Fto64U, branchy code expansion instead
// float
twoTypes{TFLOAT64, TFLOAT32}: twoOpsAndType{ssa.OpCvt64Fto32F, ssa.OpCopy, TFLOAT32},
twoTypes{TFLOAT64, TFLOAT64}: twoOpsAndType{ssa.OpCopy, ssa.OpCopy, TFLOAT64},
twoTypes{TFLOAT32, TFLOAT32}: twoOpsAndType{ssa.OpCopy, ssa.OpCopy, TFLOAT32},
twoTypes{TFLOAT32, TFLOAT64}: twoOpsAndType{ssa.OpCvt32Fto64F, ssa.OpCopy, TFLOAT64},
}
// this map is used only for 32-bit arch, and only includes the difference
// on 32-bit arch, don't use int64<->float conversion for uint32
var fpConvOpToSSA32 = map[twoTypes]twoOpsAndType{
twoTypes{TUINT32, TFLOAT32}: twoOpsAndType{ssa.OpCopy, ssa.OpCvt32Uto32F, TUINT32},
twoTypes{TUINT32, TFLOAT64}: twoOpsAndType{ssa.OpCopy, ssa.OpCvt32Uto64F, TUINT32},
twoTypes{TFLOAT32, TUINT32}: twoOpsAndType{ssa.OpCvt32Fto32U, ssa.OpCopy, TUINT32},
twoTypes{TFLOAT64, TUINT32}: twoOpsAndType{ssa.OpCvt64Fto32U, ssa.OpCopy, TUINT32},
}
var shiftOpToSSA = map[opAndTwoTypes]ssa.Op{
opAndTwoTypes{OLSH, TINT8, TUINT8}: ssa.OpLsh8x8,
opAndTwoTypes{OLSH, TUINT8, TUINT8}: ssa.OpLsh8x8,
opAndTwoTypes{OLSH, TINT8, TUINT16}: ssa.OpLsh8x16,
opAndTwoTypes{OLSH, TUINT8, TUINT16}: ssa.OpLsh8x16,
opAndTwoTypes{OLSH, TINT8, TUINT32}: ssa.OpLsh8x32,
opAndTwoTypes{OLSH, TUINT8, TUINT32}: ssa.OpLsh8x32,
opAndTwoTypes{OLSH, TINT8, TUINT64}: ssa.OpLsh8x64,
opAndTwoTypes{OLSH, TUINT8, TUINT64}: ssa.OpLsh8x64,
opAndTwoTypes{OLSH, TINT16, TUINT8}: ssa.OpLsh16x8,
opAndTwoTypes{OLSH, TUINT16, TUINT8}: ssa.OpLsh16x8,
opAndTwoTypes{OLSH, TINT16, TUINT16}: ssa.OpLsh16x16,
opAndTwoTypes{OLSH, TUINT16, TUINT16}: ssa.OpLsh16x16,
opAndTwoTypes{OLSH, TINT16, TUINT32}: ssa.OpLsh16x32,
opAndTwoTypes{OLSH, TUINT16, TUINT32}: ssa.OpLsh16x32,
opAndTwoTypes{OLSH, TINT16, TUINT64}: ssa.OpLsh16x64,
opAndTwoTypes{OLSH, TUINT16, TUINT64}: ssa.OpLsh16x64,
opAndTwoTypes{OLSH, TINT32, TUINT8}: ssa.OpLsh32x8,
opAndTwoTypes{OLSH, TUINT32, TUINT8}: ssa.OpLsh32x8,
opAndTwoTypes{OLSH, TINT32, TUINT16}: ssa.OpLsh32x16,
opAndTwoTypes{OLSH, TUINT32, TUINT16}: ssa.OpLsh32x16,
opAndTwoTypes{OLSH, TINT32, TUINT32}: ssa.OpLsh32x32,
opAndTwoTypes{OLSH, TUINT32, TUINT32}: ssa.OpLsh32x32,
opAndTwoTypes{OLSH, TINT32, TUINT64}: ssa.OpLsh32x64,
opAndTwoTypes{OLSH, TUINT32, TUINT64}: ssa.OpLsh32x64,
opAndTwoTypes{OLSH, TINT64, TUINT8}: ssa.OpLsh64x8,
opAndTwoTypes{OLSH, TUINT64, TUINT8}: ssa.OpLsh64x8,
opAndTwoTypes{OLSH, TINT64, TUINT16}: ssa.OpLsh64x16,
opAndTwoTypes{OLSH, TUINT64, TUINT16}: ssa.OpLsh64x16,
opAndTwoTypes{OLSH, TINT64, TUINT32}: ssa.OpLsh64x32,
opAndTwoTypes{OLSH, TUINT64, TUINT32}: ssa.OpLsh64x32,
opAndTwoTypes{OLSH, TINT64, TUINT64}: ssa.OpLsh64x64,
opAndTwoTypes{OLSH, TUINT64, TUINT64}: ssa.OpLsh64x64,
opAndTwoTypes{ORSH, TINT8, TUINT8}: ssa.OpRsh8x8,
opAndTwoTypes{ORSH, TUINT8, TUINT8}: ssa.OpRsh8Ux8,
opAndTwoTypes{ORSH, TINT8, TUINT16}: ssa.OpRsh8x16,
opAndTwoTypes{ORSH, TUINT8, TUINT16}: ssa.OpRsh8Ux16,
opAndTwoTypes{ORSH, TINT8, TUINT32}: ssa.OpRsh8x32,
opAndTwoTypes{ORSH, TUINT8, TUINT32}: ssa.OpRsh8Ux32,
opAndTwoTypes{ORSH, TINT8, TUINT64}: ssa.OpRsh8x64,
opAndTwoTypes{ORSH, TUINT8, TUINT64}: ssa.OpRsh8Ux64,
opAndTwoTypes{ORSH, TINT16, TUINT8}: ssa.OpRsh16x8,
opAndTwoTypes{ORSH, TUINT16, TUINT8}: ssa.OpRsh16Ux8,
opAndTwoTypes{ORSH, TINT16, TUINT16}: ssa.OpRsh16x16,
opAndTwoTypes{ORSH, TUINT16, TUINT16}: ssa.OpRsh16Ux16,
opAndTwoTypes{ORSH, TINT16, TUINT32}: ssa.OpRsh16x32,
opAndTwoTypes{ORSH, TUINT16, TUINT32}: ssa.OpRsh16Ux32,
opAndTwoTypes{ORSH, TINT16, TUINT64}: ssa.OpRsh16x64,
opAndTwoTypes{ORSH, TUINT16, TUINT64}: ssa.OpRsh16Ux64,
opAndTwoTypes{ORSH, TINT32, TUINT8}: ssa.OpRsh32x8,
opAndTwoTypes{ORSH, TUINT32, TUINT8}: ssa.OpRsh32Ux8,
opAndTwoTypes{ORSH, TINT32, TUINT16}: ssa.OpRsh32x16,
opAndTwoTypes{ORSH, TUINT32, TUINT16}: ssa.OpRsh32Ux16,
opAndTwoTypes{ORSH, TINT32, TUINT32}: ssa.OpRsh32x32,
opAndTwoTypes{ORSH, TUINT32, TUINT32}: ssa.OpRsh32Ux32,
opAndTwoTypes{ORSH, TINT32, TUINT64}: ssa.OpRsh32x64,
opAndTwoTypes{ORSH, TUINT32, TUINT64}: ssa.OpRsh32Ux64,
opAndTwoTypes{ORSH, TINT64, TUINT8}: ssa.OpRsh64x8,
opAndTwoTypes{ORSH, TUINT64, TUINT8}: ssa.OpRsh64Ux8,
opAndTwoTypes{ORSH, TINT64, TUINT16}: ssa.OpRsh64x16,
opAndTwoTypes{ORSH, TUINT64, TUINT16}: ssa.OpRsh64Ux16,
opAndTwoTypes{ORSH, TINT64, TUINT32}: ssa.OpRsh64x32,
opAndTwoTypes{ORSH, TUINT64, TUINT32}: ssa.OpRsh64Ux32,
opAndTwoTypes{ORSH, TINT64, TUINT64}: ssa.OpRsh64x64,
opAndTwoTypes{ORSH, TUINT64, TUINT64}: ssa.OpRsh64Ux64,
}
func (s *state) ssaShiftOp(op Op, t *Type, u *Type) ssa.Op {
etype1 := s.concreteEtype(t)
etype2 := s.concreteEtype(u)
x, ok := shiftOpToSSA[opAndTwoTypes{op, etype1, etype2}]
if !ok {
s.Unimplementedf("unhandled shift op %s etype=%s/%s", op, etype1, etype2)
}
return x
}
func (s *state) ssaRotateOp(op Op, t *Type) ssa.Op {
etype1 := s.concreteEtype(t)
x, ok := opToSSA[opAndType{op, etype1}]
if !ok {
s.Unimplementedf("unhandled rotate op %s etype=%s", op, etype1)
}
return x
}
// expr converts the expression n to ssa, adds it to s and returns the ssa result.
func (s *state) expr(n *Node) *ssa.Value {
if !(n.Op == ONAME || n.Op == OLITERAL && n.Sym != nil) {
// ONAMEs and named OLITERALs have the line number
// of the decl, not the use. See issue 14742.
s.pushLine(n.Lineno)
defer s.popLine()
}
s.stmtList(n.Ninit)
switch n.Op {
case OCFUNC:
aux := s.lookupSymbol(n, &ssa.ExternSymbol{Typ: n.Type, Sym: n.Left.Sym})
return s.entryNewValue1A(ssa.OpAddr, n.Type, aux, s.sb)
case ONAME:
if n.Class == PFUNC {
// "value" of a function is the address of the function's closure
sym := funcsym(n.Sym)
aux := &ssa.ExternSymbol{Typ: n.Type, Sym: sym}
return s.entryNewValue1A(ssa.OpAddr, Ptrto(n.Type), aux, s.sb)
}
if s.canSSA(n) {
return s.variable(n, n.Type)
}
addr, _ := s.addr(n, false)
return s.newValue2(ssa.OpLoad, n.Type, addr, s.mem())
case OCLOSUREVAR:
addr, _ := s.addr(n, false)
return s.newValue2(ssa.OpLoad, n.Type, addr, s.mem())
case OLITERAL:
switch u := n.Val().U.(type) {
case *Mpint:
i := u.Int64()
switch n.Type.Size() {
case 1:
return s.constInt8(n.Type, int8(i))
case 2:
return s.constInt16(n.Type, int16(i))
case 4:
return s.constInt32(n.Type, int32(i))
case 8:
return s.constInt64(n.Type, i)
default:
s.Fatalf("bad integer size %d", n.Type.Size())
return nil
}
case string:
if u == "" {
return s.constEmptyString(n.Type)
}
return s.entryNewValue0A(ssa.OpConstString, n.Type, u)
case bool:
return s.constBool(u)
case *NilVal:
t := n.Type
switch {
case t.IsSlice():
return s.constSlice(t)
case t.IsInterface():
return s.constInterface(t)
default:
return s.constNil(t)
}
case *Mpflt:
switch n.Type.Size() {
case 4:
return s.constFloat32(n.Type, u.Float32())
case 8:
return s.constFloat64(n.Type, u.Float64())
default:
s.Fatalf("bad float size %d", n.Type.Size())
return nil
}
case *Mpcplx:
r := &u.Real
i := &u.Imag
switch n.Type.Size() {
case 8:
pt := Types[TFLOAT32]
return s.newValue2(ssa.OpComplexMake, n.Type,
s.constFloat32(pt, r.Float32()),
s.constFloat32(pt, i.Float32()))
case 16:
pt := Types[TFLOAT64]
return s.newValue2(ssa.OpComplexMake, n.Type,
s.constFloat64(pt, r.Float64()),
s.constFloat64(pt, i.Float64()))
default:
s.Fatalf("bad float size %d", n.Type.Size())
return nil
}
default:
s.Unimplementedf("unhandled OLITERAL %v", n.Val().Ctype())
return nil
}
case OCONVNOP:
to := n.Type
from := n.Left.Type
// Assume everything will work out, so set up our return value.
// Anything interesting that happens from here is a fatal.
x := s.expr(n.Left)
// Special case for not confusing GC and liveness.
// We don't want pointers accidentally classified
// as not-pointers or vice-versa because of copy
// elision.
if to.IsPtrShaped() != from.IsPtrShaped() {
return s.newValue2(ssa.OpConvert, to, x, s.mem())
}
v := s.newValue1(ssa.OpCopy, to, x) // ensure that v has the right type
// CONVNOP closure
if to.Etype == TFUNC && from.IsPtrShaped() {
return v
}
// named <--> unnamed type or typed <--> untyped const
if from.Etype == to.Etype {
return v
}
// unsafe.Pointer <--> *T
if to.Etype == TUNSAFEPTR && from.IsPtr() || from.Etype == TUNSAFEPTR && to.IsPtr() {
return v
}
dowidth(from)
dowidth(to)
if from.Width != to.Width {
s.Fatalf("CONVNOP width mismatch %v (%d) -> %v (%d)\n", from, from.Width, to, to.Width)
return nil
}
if etypesign(from.Etype) != etypesign(to.Etype) {
s.Fatalf("CONVNOP sign mismatch %v (%s) -> %v (%s)\n", from, from.Etype, to, to.Etype)
return nil
}
if instrumenting {
// These appear to be fine, but they fail the
// integer constraint below, so okay them here.
// Sample non-integer conversion: map[string]string -> *uint8
return v
}
if etypesign(from.Etype) == 0 {
s.Fatalf("CONVNOP unrecognized non-integer %v -> %v\n", from, to)
return nil
}
// integer, same width, same sign
return v
case OCONV:
x := s.expr(n.Left)
ft := n.Left.Type // from type
tt := n.Type // to type
if ft.IsInteger() && tt.IsInteger() {
var op ssa.Op
if tt.Size() == ft.Size() {
op = ssa.OpCopy
} else if tt.Size() < ft.Size() {
// truncation
switch 10*ft.Size() + tt.Size() {
case 21:
op = ssa.OpTrunc16to8
case 41:
op = ssa.OpTrunc32to8
case 42:
op = ssa.OpTrunc32to16
case 81:
op = ssa.OpTrunc64to8
case 82:
op = ssa.OpTrunc64to16
case 84:
op = ssa.OpTrunc64to32
default:
s.Fatalf("weird integer truncation %s -> %s", ft, tt)
}
} else if ft.IsSigned() {
// sign extension
switch 10*ft.Size() + tt.Size() {
case 12:
op = ssa.OpSignExt8to16
case 14:
op = ssa.OpSignExt8to32
case 18:
op = ssa.OpSignExt8to64
case 24:
op = ssa.OpSignExt16to32
case 28:
op = ssa.OpSignExt16to64
case 48:
op = ssa.OpSignExt32to64
default:
s.Fatalf("bad integer sign extension %s -> %s", ft, tt)
}
} else {
// zero extension
switch 10*ft.Size() + tt.Size() {
case 12:
op = ssa.OpZeroExt8to16
case 14:
op = ssa.OpZeroExt8to32
case 18:
op = ssa.OpZeroExt8to64
case 24:
op = ssa.OpZeroExt16to32
case 28:
op = ssa.OpZeroExt16to64
case 48:
op = ssa.OpZeroExt32to64
default:
s.Fatalf("weird integer sign extension %s -> %s", ft, tt)
}
}
return s.newValue1(op, n.Type, x)
}
if ft.IsFloat() || tt.IsFloat() {
conv, ok := fpConvOpToSSA[twoTypes{s.concreteEtype(ft), s.concreteEtype(tt)}]
if s.config.IntSize == 4 && Thearch.LinkArch.Name != "amd64p32" {
if conv1, ok1 := fpConvOpToSSA32[twoTypes{s.concreteEtype(ft), s.concreteEtype(tt)}]; ok1 {
conv = conv1
}
}
if !ok {
s.Fatalf("weird float conversion %s -> %s", ft, tt)
}
op1, op2, it := conv.op1, conv.op2, conv.intermediateType
if op1 != ssa.OpInvalid && op2 != ssa.OpInvalid {
// normal case, not tripping over unsigned 64
if op1 == ssa.OpCopy {
if op2 == ssa.OpCopy {
return x
}
return s.newValue1(op2, n.Type, x)
}
if op2 == ssa.OpCopy {
return s.newValue1(op1, n.Type, x)
}
return s.newValue1(op2, n.Type, s.newValue1(op1, Types[it], x))
}
// Tricky 64-bit unsigned cases.
if ft.IsInteger() {
// therefore tt is float32 or float64, and ft is also unsigned
if tt.Size() == 4 {
return s.uint64Tofloat32(n, x, ft, tt)
}
if tt.Size() == 8 {
return s.uint64Tofloat64(n, x, ft, tt)
}
s.Fatalf("weird unsigned integer to float conversion %s -> %s", ft, tt)
}
// therefore ft is float32 or float64, and tt is unsigned integer
if ft.Size() == 4 {
return s.float32ToUint64(n, x, ft, tt)
}
if ft.Size() == 8 {
return s.float64ToUint64(n, x, ft, tt)
}
s.Fatalf("weird float to unsigned integer conversion %s -> %s", ft, tt)
return nil
}
if ft.IsComplex() && tt.IsComplex() {
var op ssa.Op
if ft.Size() == tt.Size() {
op = ssa.OpCopy
} else if ft.Size() == 8 && tt.Size() == 16 {
op = ssa.OpCvt32Fto64F
} else if ft.Size() == 16 && tt.Size() == 8 {
op = ssa.OpCvt64Fto32F
} else {
s.Fatalf("weird complex conversion %s -> %s", ft, tt)
}
ftp := floatForComplex(ft)
ttp := floatForComplex(tt)
return s.newValue2(ssa.OpComplexMake, tt,
s.newValue1(op, ttp, s.newValue1(ssa.OpComplexReal, ftp, x)),
s.newValue1(op, ttp, s.newValue1(ssa.OpComplexImag, ftp, x)))
}
s.Unimplementedf("unhandled OCONV %s -> %s", n.Left.Type.Etype, n.Type.Etype)
return nil
case ODOTTYPE:
res, _ := s.dottype(n, false)
return res
// binary ops
case OLT, OEQ, ONE, OLE, OGE, OGT:
a := s.expr(n.Left)
b := s.expr(n.Right)
if n.Left.Type.IsComplex() {
pt := floatForComplex(n.Left.Type)
op := s.ssaOp(OEQ, pt)
r := s.newValue2(op, Types[TBOOL], s.newValue1(ssa.OpComplexReal, pt, a), s.newValue1(ssa.OpComplexReal, pt, b))
i := s.newValue2(op, Types[TBOOL], s.newValue1(ssa.OpComplexImag, pt, a), s.newValue1(ssa.OpComplexImag, pt, b))
c := s.newValue2(ssa.OpAnd8, Types[TBOOL], r, i)
switch n.Op {
case OEQ:
return c
case ONE:
return s.newValue1(ssa.OpNot, Types[TBOOL], c)
default:
s.Fatalf("ordered complex compare %s", n.Op)
}
}
return s.newValue2(s.ssaOp(n.Op, n.Left.Type), Types[TBOOL], a, b)
case OMUL:
a := s.expr(n.Left)
b := s.expr(n.Right)
if n.Type.IsComplex() {
mulop := ssa.OpMul64F
addop := ssa.OpAdd64F
subop := ssa.OpSub64F
pt := floatForComplex(n.Type) // Could be Float32 or Float64
wt := Types[TFLOAT64] // Compute in Float64 to minimize cancelation error
areal := s.newValue1(ssa.OpComplexReal, pt, a)
breal := s.newValue1(ssa.OpComplexReal, pt, b)
aimag := s.newValue1(ssa.OpComplexImag, pt, a)
bimag := s.newValue1(ssa.OpComplexImag, pt, b)
if pt != wt { // Widen for calculation
areal = s.newValue1(ssa.OpCvt32Fto64F, wt, areal)
breal = s.newValue1(ssa.OpCvt32Fto64F, wt, breal)
aimag = s.newValue1(ssa.OpCvt32Fto64F, wt, aimag)
bimag = s.newValue1(ssa.OpCvt32Fto64F, wt, bimag)
}
xreal := s.newValue2(subop, wt, s.newValue2(mulop, wt, areal, breal), s.newValue2(mulop, wt, aimag, bimag))
ximag := s.newValue2(addop, wt, s.newValue2(mulop, wt, areal, bimag), s.newValue2(mulop, wt, aimag, breal))
if pt != wt { // Narrow to store back
xreal = s.newValue1(ssa.OpCvt64Fto32F, pt, xreal)
ximag = s.newValue1(ssa.OpCvt64Fto32F, pt, ximag)
}
return s.newValue2(ssa.OpComplexMake, n.Type, xreal, ximag)
}
return s.newValue2(s.ssaOp(n.Op, n.Type), a.Type, a, b)
case ODIV:
a := s.expr(n.Left)
b := s.expr(n.Right)
if n.Type.IsComplex() {
// TODO this is not executed because the front-end substitutes a runtime call.
// That probably ought to change; with modest optimization the widen/narrow
// conversions could all be elided in larger expression trees.
mulop := ssa.OpMul64F
addop := ssa.OpAdd64F
subop := ssa.OpSub64F
divop := ssa.OpDiv64F
pt := floatForComplex(n.Type) // Could be Float32 or Float64
wt := Types[TFLOAT64] // Compute in Float64 to minimize cancelation error
areal := s.newValue1(ssa.OpComplexReal, pt, a)
breal := s.newValue1(ssa.OpComplexReal, pt, b)
aimag := s.newValue1(ssa.OpComplexImag, pt, a)
bimag := s.newValue1(ssa.OpComplexImag, pt, b)
if pt != wt { // Widen for calculation
areal = s.newValue1(ssa.OpCvt32Fto64F, wt, areal)
breal = s.newValue1(ssa.OpCvt32Fto64F, wt, breal)
aimag = s.newValue1(ssa.OpCvt32Fto64F, wt, aimag)
bimag = s.newValue1(ssa.OpCvt32Fto64F, wt, bimag)
}
denom := s.newValue2(addop, wt, s.newValue2(mulop, wt, breal, breal), s.newValue2(mulop, wt, bimag, bimag))
xreal := s.newValue2(addop, wt, s.newValue2(mulop, wt, areal, breal), s.newValue2(mulop, wt, aimag, bimag))
ximag := s.newValue2(subop, wt, s.newValue2(mulop, wt, aimag, breal), s.newValue2(mulop, wt, areal, bimag))
// TODO not sure if this is best done in wide precision or narrow
// Double-rounding might be an issue.
// Note that the pre-SSA implementation does the entire calculation
// in wide format, so wide is compatible.
xreal = s.newValue2(divop, wt, xreal, denom)
ximag = s.newValue2(divop, wt, ximag, denom)
if pt != wt { // Narrow to store back
xreal = s.newValue1(ssa.OpCvt64Fto32F, pt, xreal)
ximag = s.newValue1(ssa.OpCvt64Fto32F, pt, ximag)
}
return s.newValue2(ssa.OpComplexMake, n.Type, xreal, ximag)
}
if n.Type.IsFloat() {
return s.newValue2(s.ssaOp(n.Op, n.Type), a.Type, a, b)
} else {
// do a size-appropriate check for zero
cmp := s.newValue2(s.ssaOp(ONE, n.Type), Types[TBOOL], b, s.zeroVal(n.Type))
s.check(cmp, panicdivide)
return s.newValue2(s.ssaOp(n.Op, n.Type), a.Type, a, b)
}
case OMOD:
a := s.expr(n.Left)
b := s.expr(n.Right)
// do a size-appropriate check for zero
cmp := s.newValue2(s.ssaOp(ONE, n.Type), Types[TBOOL], b, s.zeroVal(n.Type))
s.check(cmp, panicdivide)
return s.newValue2(s.ssaOp(n.Op, n.Type), a.Type, a, b)
case OADD, OSUB:
a := s.expr(n.Left)
b := s.expr(n.Right)
if n.Type.IsComplex() {
pt := floatForComplex(n.Type)
op := s.ssaOp(n.Op, pt)
return s.newValue2(ssa.OpComplexMake, n.Type,
s.newValue2(op, pt, s.newValue1(ssa.OpComplexReal, pt, a), s.newValue1(ssa.OpComplexReal, pt, b)),
s.newValue2(op, pt, s.newValue1(ssa.OpComplexImag, pt, a), s.newValue1(ssa.OpComplexImag, pt, b)))
}
return s.newValue2(s.ssaOp(n.Op, n.Type), a.Type, a, b)
case OAND, OOR, OHMUL, OXOR:
a := s.expr(n.Left)
b := s.expr(n.Right)
return s.newValue2(s.ssaOp(n.Op, n.Type), a.Type, a, b)
case OLSH, ORSH:
a := s.expr(n.Left)
b := s.expr(n.Right)
return s.newValue2(s.ssaShiftOp(n.Op, n.Type, n.Right.Type), a.Type, a, b)
case OLROT:
a := s.expr(n.Left)
i := n.Right.Int64()
if i <= 0 || i >= n.Type.Size()*8 {
s.Fatalf("Wrong rotate distance for LROT, expected 1 through %d, saw %d", n.Type.Size()*8-1, i)
}
return s.newValue1I(s.ssaRotateOp(n.Op, n.Type), a.Type, i, a)
case OANDAND, OOROR:
// To implement OANDAND (and OOROR), we introduce a
// new temporary variable to hold the result. The
// variable is associated with the OANDAND node in the
// s.vars table (normally variables are only
// associated with ONAME nodes). We convert
// A && B
// to
// var = A
// if var {
// var = B
// }
// Using var in the subsequent block introduces the
// necessary phi variable.
el := s.expr(n.Left)
s.vars[n] = el
b := s.endBlock()
b.Kind = ssa.BlockIf
b.SetControl(el)
// In theory, we should set b.Likely here based on context.
// However, gc only gives us likeliness hints
// in a single place, for plain OIF statements,
// and passing around context is finnicky, so don't bother for now.
bRight := s.f.NewBlock(ssa.BlockPlain)
bResult := s.f.NewBlock(ssa.BlockPlain)
if n.Op == OANDAND {
b.AddEdgeTo(bRight)
b.AddEdgeTo(bResult)
} else if n.Op == OOROR {
b.AddEdgeTo(bResult)
b.AddEdgeTo(bRight)
}
s.startBlock(bRight)
er := s.expr(n.Right)
s.vars[n] = er
b = s.endBlock()
b.AddEdgeTo(bResult)
s.startBlock(bResult)
return s.variable(n, Types[TBOOL])
case OCOMPLEX:
r := s.expr(n.Left)
i := s.expr(n.Right)
return s.newValue2(ssa.OpComplexMake, n.Type, r, i)
// unary ops
case OMINUS:
a := s.expr(n.Left)
if n.Type.IsComplex() {
tp := floatForComplex(n.Type)
negop := s.ssaOp(n.Op, tp)
return s.newValue2(ssa.OpComplexMake, n.Type,
s.newValue1(negop, tp, s.newValue1(ssa.OpComplexReal, tp, a)),
s.newValue1(negop, tp, s.newValue1(ssa.OpComplexImag, tp, a)))
}
return s.newValue1(s.ssaOp(n.Op, n.Type), a.Type, a)
case ONOT, OCOM, OSQRT:
a := s.expr(n.Left)
return s.newValue1(s.ssaOp(n.Op, n.Type), a.Type, a)
case OIMAG, OREAL:
a := s.expr(n.Left)
return s.newValue1(s.ssaOp(n.Op, n.Left.Type), n.Type, a)
case OPLUS:
return s.expr(n.Left)
case OADDR:
a, _ := s.addr(n.Left, n.Bounded)
// Note we know the volatile result is false because you can't write &f() in Go.
return a
case OINDREG:
if int(n.Reg) != Thearch.REGSP {
s.Unimplementedf("OINDREG of non-SP register %s in expr: %v", obj.Rconv(int(n.Reg)), n)
return nil
}
addr := s.entryNewValue1I(ssa.OpOffPtr, Ptrto(n.Type), n.Xoffset, s.sp)
return s.newValue2(ssa.OpLoad, n.Type, addr, s.mem())
case OIND:
p := s.exprPtr(n.Left, false, n.Lineno)
return s.newValue2(ssa.OpLoad, n.Type, p, s.mem())
case ODOT:
t := n.Left.Type
if canSSAType(t) {
v := s.expr(n.Left)
return s.newValue1I(ssa.OpStructSelect, n.Type, int64(fieldIdx(n)), v)
}
p, _ := s.addr(n, false)
return s.newValue2(ssa.OpLoad, n.Type, p, s.mem())
case ODOTPTR:
p := s.exprPtr(n.Left, false, n.Lineno)
p = s.newValue1I(ssa.OpOffPtr, p.Type, n.Xoffset, p)
return s.newValue2(ssa.OpLoad, n.Type, p, s.mem())
case OINDEX:
switch {
case n.Left.Type.IsString():
a := s.expr(n.Left)
i := s.expr(n.Right)
i = s.extendIndex(i, Panicindex)
if !n.Bounded {
len := s.newValue1(ssa.OpStringLen, Types[TINT], a)
s.boundsCheck(i, len)
}
ptrtyp := Ptrto(Types[TUINT8])
ptr := s.newValue1(ssa.OpStringPtr, ptrtyp, a)
if Isconst(n.Right, CTINT) {
ptr = s.newValue1I(ssa.OpOffPtr, ptrtyp, n.Right.Int64(), ptr)
} else {
ptr = s.newValue2(ssa.OpAddPtr, ptrtyp, ptr, i)
}
return s.newValue2(ssa.OpLoad, Types[TUINT8], ptr, s.mem())
case n.Left.Type.IsSlice():
p, _ := s.addr(n, false)
return s.newValue2(ssa.OpLoad, n.Left.Type.Elem(), p, s.mem())
case n.Left.Type.IsArray():
// TODO: fix when we can SSA arrays of length 1.
p, _ := s.addr(n, false)
return s.newValue2(ssa.OpLoad, n.Left.Type.Elem(), p, s.mem())
default:
s.Fatalf("bad type for index %v", n.Left.Type)
return nil
}
case OLEN, OCAP:
switch {
case n.Left.Type.IsSlice():
op := ssa.OpSliceLen
if n.Op == OCAP {
op = ssa.OpSliceCap
}
return s.newValue1(op, Types[TINT], s.expr(n.Left))
case n.Left.Type.IsString(): // string; not reachable for OCAP
return s.newValue1(ssa.OpStringLen, Types[TINT], s.expr(n.Left))
case n.Left.Type.IsMap(), n.Left.Type.IsChan():
return s.referenceTypeBuiltin(n, s.expr(n.Left))
default: // array
return s.constInt(Types[TINT], n.Left.Type.NumElem())
}
case OSPTR:
a := s.expr(n.Left)
if n.Left.Type.IsSlice() {
return s.newValue1(ssa.OpSlicePtr, n.Type, a)
} else {
return s.newValue1(ssa.OpStringPtr, n.Type, a)
}
case OITAB:
a := s.expr(n.Left)
return s.newValue1(ssa.OpITab, n.Type, a)
case OEFACE:
tab := s.expr(n.Left)
data := s.expr(n.Right)
// The frontend allows putting things like struct{*byte} in
// the data portion of an eface. But we don't want struct{*byte}
// as a register type because (among other reasons) the liveness
// analysis is confused by the "fat" variables that result from
// such types being spilled.
// So here we ensure that we are selecting the underlying pointer
// when we build an eface.
// TODO: get rid of this now that structs can be SSA'd?
for !data.Type.IsPtrShaped() {
switch {
case data.Type.IsArray():
data = s.newValue1I(ssa.OpArrayIndex, data.Type.ElemType(), 0, data)
case data.Type.IsStruct():
for i := data.Type.NumFields() - 1; i >= 0; i-- {
f := data.Type.FieldType(i)
if f.Size() == 0 {
// eface type could also be struct{p *byte; q [0]int}
continue
}
data = s.newValue1I(ssa.OpStructSelect, f, int64(i), data)
break
}
default:
s.Fatalf("type being put into an eface isn't a pointer")
}
}
return s.newValue2(ssa.OpIMake, n.Type, tab, data)
case OSLICE, OSLICEARR, OSLICE3, OSLICE3ARR:
v := s.expr(n.Left)
var i, j, k *ssa.Value
low, high, max := n.SliceBounds()
if low != nil {
i = s.extendIndex(s.expr(low), panicslice)
}
if high != nil {
j = s.extendIndex(s.expr(high), panicslice)
}
if max != nil {
k = s.extendIndex(s.expr(max), panicslice)
}
p, l, c := s.slice(n.Left.Type, v, i, j, k)
return s.newValue3(ssa.OpSliceMake, n.Type, p, l, c)
case OSLICESTR:
v := s.expr(n.Left)
var i, j *ssa.Value
low, high, _ := n.SliceBounds()
if low != nil {
i = s.extendIndex(s.expr(low), panicslice)
}
if high != nil {
j = s.extendIndex(s.expr(high), panicslice)
}
p, l, _ := s.slice(n.Left.Type, v, i, j, nil)
return s.newValue2(ssa.OpStringMake, n.Type, p, l)
case OCALLFUNC:
if isIntrinsicCall1(n) {
return s.intrinsicCall1(n)
}
fallthrough
case OCALLINTER, OCALLMETH:
a := s.call(n, callNormal)
return s.newValue2(ssa.OpLoad, n.Type, a, s.mem())
case OGETG:
return s.newValue1(ssa.OpGetG, n.Type, s.mem())
case OAPPEND:
return s.append(n, false)
default:
s.Unimplementedf("unhandled expr %s", n.Op)
return nil
}
}
// append converts an OAPPEND node to SSA.
// If inplace is false, it converts the OAPPEND expression n to an ssa.Value,
// adds it to s, and returns the Value.
// If inplace is true, it writes the result of the OAPPEND expression n
// back to the slice being appended to, and returns nil.
// inplace MUST be set to false if the slice can be SSA'd.
func (s *state) append(n *Node, inplace bool) *ssa.Value {
// If inplace is false, process as expression "append(s, e1, e2, e3)":
//
// ptr, len, cap := s
// newlen := len + 3
// if newlen > cap {
// ptr, len, cap = growslice(s, newlen)
// newlen = len + 3 // recalculate to avoid a spill
// }
// // with write barriers, if needed:
// *(ptr+len) = e1
// *(ptr+len+1) = e2
// *(ptr+len+2) = e3
// return makeslice(ptr, newlen, cap)
//
//
// If inplace is true, process as statement "s = append(s, e1, e2, e3)":
//
// a := &s
// ptr, len, cap := s
// newlen := len + 3
// if newlen > cap {
// newptr, len, newcap = growslice(ptr, len, cap, newlen)
// vardef(a) // if necessary, advise liveness we are writing a new a
// *a.cap = newcap // write before ptr to avoid a spill
// *a.ptr = newptr // with write barrier
// }
// newlen = len + 3 // recalculate to avoid a spill
// *a.len = newlen
// // with write barriers, if needed:
// *(ptr+len) = e1
// *(ptr+len+1) = e2
// *(ptr+len+2) = e3
et := n.Type.Elem()
pt := Ptrto(et)
// Evaluate slice
sn := n.List.First() // the slice node is the first in the list
var slice, addr *ssa.Value
if inplace {
addr, _ = s.addr(sn, false)
slice = s.newValue2(ssa.OpLoad, n.Type, addr, s.mem())
} else {
slice = s.expr(sn)
}
// Allocate new blocks
grow := s.f.NewBlock(ssa.BlockPlain)
assign := s.f.NewBlock(ssa.BlockPlain)
// Decide if we need to grow
nargs := int64(n.List.Len() - 1)
p := s.newValue1(ssa.OpSlicePtr, pt, slice)
l := s.newValue1(ssa.OpSliceLen, Types[TINT], slice)
c := s.newValue1(ssa.OpSliceCap, Types[TINT], slice)
nl := s.newValue2(s.ssaOp(OADD, Types[TINT]), Types[TINT], l, s.constInt(Types[TINT], nargs))
cmp := s.newValue2(s.ssaOp(OGT, Types[TINT]), Types[TBOOL], nl, c)
s.vars[&ptrVar] = p
if !inplace {
s.vars[&newlenVar] = nl
s.vars[&capVar] = c
} else {
s.vars[&lenVar] = l
}
b := s.endBlock()
b.Kind = ssa.BlockIf
b.Likely = ssa.BranchUnlikely
b.SetControl(cmp)
b.AddEdgeTo(grow)
b.AddEdgeTo(assign)
// Call growslice
s.startBlock(grow)
taddr := s.newValue1A(ssa.OpAddr, Types[TUINTPTR], &ssa.ExternSymbol{Typ: Types[TUINTPTR], Sym: typenamesym(n.Type.Elem())}, s.sb)
r := s.rtcall(growslice, true, []*Type{pt, Types[TINT], Types[TINT]}, taddr, p, l, c, nl)
if inplace {
if sn.Op == ONAME {
// Tell liveness we're about to build a new slice
s.vars[&memVar] = s.newValue1A(ssa.OpVarDef, ssa.TypeMem, sn, s.mem())
}
capaddr := s.newValue1I(ssa.OpOffPtr, pt, int64(Array_cap), addr)
s.vars[&memVar] = s.newValue3I(ssa.OpStore, ssa.TypeMem, s.config.IntSize, capaddr, r[2], s.mem())
s.insertWBstore(pt, addr, r[0], n.Lineno, 0)
// load the value we just stored to avoid having to spill it
s.vars[&ptrVar] = s.newValue2(ssa.OpLoad, pt, addr, s.mem())
s.vars[&lenVar] = r[1] // avoid a spill in the fast path
} else {
s.vars[&ptrVar] = r[0]
s.vars[&newlenVar] = s.newValue2(s.ssaOp(OADD, Types[TINT]), Types[TINT], r[1], s.constInt(Types[TINT], nargs))
s.vars[&capVar] = r[2]
}
b = s.endBlock()
b.AddEdgeTo(assign)
// assign new elements to slots
s.startBlock(assign)
if inplace {
l = s.variable(&lenVar, Types[TINT]) // generates phi for len
nl = s.newValue2(s.ssaOp(OADD, Types[TINT]), Types[TINT], l, s.constInt(Types[TINT], nargs))
lenaddr := s.newValue1I(ssa.OpOffPtr, pt, int64(Array_nel), addr)
s.vars[&memVar] = s.newValue3I(ssa.OpStore, ssa.TypeMem, s.config.IntSize, lenaddr, nl, s.mem())
}
// Evaluate args
type argRec struct {
// if store is true, we're appending the value v. If false, we're appending the
// value at *v. If store==false, isVolatile reports whether the source
// is in the outargs section of the stack frame.
v *ssa.Value
store bool
isVolatile bool
}
args := make([]argRec, 0, nargs)
for _, n := range n.List.Slice()[1:] {
if canSSAType(n.Type) {
args = append(args, argRec{v: s.expr(n), store: true})
} else {
v, isVolatile := s.addr(n, false)
args = append(args, argRec{v: v, isVolatile: isVolatile})
}
}
p = s.variable(&ptrVar, pt) // generates phi for ptr
if !inplace {
nl = s.variable(&newlenVar, Types[TINT]) // generates phi for nl
c = s.variable(&capVar, Types[TINT]) // generates phi for cap
}
p2 := s.newValue2(ssa.OpPtrIndex, pt, p, l)
// TODO: just one write barrier call for all of these writes?
// TODO: maybe just one writeBarrier.enabled check?
for i, arg := range args {
addr := s.newValue2(ssa.OpPtrIndex, pt, p2, s.constInt(Types[TINT], int64(i)))
if arg.store {
if haspointers(et) {
s.insertWBstore(et, addr, arg.v, n.Lineno, 0)
} else {
s.vars[&memVar] = s.newValue3I(ssa.OpStore, ssa.TypeMem, et.Size(), addr, arg.v, s.mem())
}
} else {
if haspointers(et) {
s.insertWBmove(et, addr, arg.v, n.Lineno, arg.isVolatile)
} else {
s.vars[&memVar] = s.newValue3I(ssa.OpMove, ssa.TypeMem, SizeAlignAuxInt(et), addr, arg.v, s.mem())
}
}
}
delete(s.vars, &ptrVar)
if inplace {
delete(s.vars, &lenVar)
return nil
}
delete(s.vars, &newlenVar)
delete(s.vars, &capVar)
// make result
return s.newValue3(ssa.OpSliceMake, n.Type, p, nl, c)
}
// condBranch evaluates the boolean expression cond and branches to yes
// if cond is true and no if cond is false.
// This function is intended to handle && and || better than just calling
// s.expr(cond) and branching on the result.
func (s *state) condBranch(cond *Node, yes, no *ssa.Block, likely int8) {
if cond.Op == OANDAND {
mid := s.f.NewBlock(ssa.BlockPlain)
s.stmtList(cond.Ninit)
s.condBranch(cond.Left, mid, no, max8(likely, 0))
s.startBlock(mid)
s.condBranch(cond.Right, yes, no, likely)
return
// Note: if likely==1, then both recursive calls pass 1.
// If likely==-1, then we don't have enough information to decide
// whether the first branch is likely or not. So we pass 0 for
// the likeliness of the first branch.
// TODO: have the frontend give us branch prediction hints for
// OANDAND and OOROR nodes (if it ever has such info).
}
if cond.Op == OOROR {
mid := s.f.NewBlock(ssa.BlockPlain)
s.stmtList(cond.Ninit)
s.condBranch(cond.Left, yes, mid, min8(likely, 0))
s.startBlock(mid)
s.condBranch(cond.Right, yes, no, likely)
return
// Note: if likely==-1, then both recursive calls pass -1.
// If likely==1, then we don't have enough info to decide
// the likelihood of the first branch.
}
if cond.Op == ONOT {
s.stmtList(cond.Ninit)
s.condBranch(cond.Left, no, yes, -likely)
return
}
c := s.expr(cond)
b := s.endBlock()
b.Kind = ssa.BlockIf
b.SetControl(c)
b.Likely = ssa.BranchPrediction(likely) // gc and ssa both use -1/0/+1 for likeliness
b.AddEdgeTo(yes)
b.AddEdgeTo(no)
}
type skipMask uint8
const (
skipPtr skipMask = 1 << iota
skipLen
skipCap
)
// assign does left = right.
// Right has already been evaluated to ssa, left has not.
// If deref is true, then we do left = *right instead (and right has already been nil-checked).
// If deref is true and right == nil, just do left = 0.
// If deref is true, rightIsVolatile reports whether right points to volatile (clobbered by a call) storage.
// Include a write barrier if wb is true.
// skip indicates assignments (at the top level) that can be avoided.
func (s *state) assign(left *Node, right *ssa.Value, wb, deref bool, line int32, skip skipMask, rightIsVolatile bool) {
if left.Op == ONAME && isblank(left) {
return
}
t := left.Type
dowidth(t)
if s.canSSA(left) {
if deref {
s.Fatalf("can SSA LHS %s but not RHS %s", left, right)
}
if left.Op == ODOT {
// We're assigning to a field of an ssa-able value.
// We need to build a new structure with the new value for the
// field we're assigning and the old values for the other fields.
// For instance:
// type T struct {a, b, c int}
// var T x
// x.b = 5
// For the x.b = 5 assignment we want to generate x = T{x.a, 5, x.c}
// Grab information about the structure type.
t := left.Left.Type
nf := t.NumFields()
idx := fieldIdx(left)
// Grab old value of structure.
old := s.expr(left.Left)
// Make new structure.
new := s.newValue0(ssa.StructMakeOp(t.NumFields()), t)
// Add fields as args.
for i := 0; i < nf; i++ {
if i == idx {
new.AddArg(right)
} else {
new.AddArg(s.newValue1I(ssa.OpStructSelect, t.FieldType(i), int64(i), old))
}
}
// Recursively assign the new value we've made to the base of the dot op.
s.assign(left.Left, new, false, false, line, 0, rightIsVolatile)
// TODO: do we need to update named values here?
return
}
// Update variable assignment.
s.vars[left] = right
s.addNamedValue(left, right)
return
}
// Left is not ssa-able. Compute its address.
addr, _ := s.addr(left, false)
if left.Op == ONAME && skip == 0 {
s.vars[&memVar] = s.newValue1A(ssa.OpVarDef, ssa.TypeMem, left, s.mem())
}
if deref {
// Treat as a mem->mem move.
if right == nil {
s.vars[&memVar] = s.newValue2I(ssa.OpZero, ssa.TypeMem, SizeAlignAuxInt(t), addr, s.mem())
return
}
if wb {
s.insertWBmove(t, addr, right, line, rightIsVolatile)
return
}
s.vars[&memVar] = s.newValue3I(ssa.OpMove, ssa.TypeMem, SizeAlignAuxInt(t), addr, right, s.mem())
return
}
// Treat as a store.
if wb {
if skip&skipPtr != 0 {
// Special case: if we don't write back the pointers, don't bother
// doing the write barrier check.
s.storeTypeScalars(t, addr, right, skip)
return
}
s.insertWBstore(t, addr, right, line, skip)
return
}
if skip != 0 {
if skip&skipPtr == 0 {
s.storeTypePtrs(t, addr, right)
}
s.storeTypeScalars(t, addr, right, skip)
return
}
s.vars[&memVar] = s.newValue3I(ssa.OpStore, ssa.TypeMem, t.Size(), addr, right, s.mem())
}
// zeroVal returns the zero value for type t.
func (s *state) zeroVal(t *Type) *ssa.Value {
switch {
case t.IsInteger():
switch t.Size() {
case 1:
return s.constInt8(t, 0)
case 2:
return s.constInt16(t, 0)
case 4:
return s.constInt32(t, 0)
case 8:
return s.constInt64(t, 0)
default:
s.Fatalf("bad sized integer type %s", t)
}
case t.IsFloat():
switch t.Size() {
case 4:
return s.constFloat32(t, 0)
case 8:
return s.constFloat64(t, 0)
default:
s.Fatalf("bad sized float type %s", t)
}
case t.IsComplex():
switch t.Size() {
case 8:
z := s.constFloat32(Types[TFLOAT32], 0)
return s.entryNewValue2(ssa.OpComplexMake, t, z, z)
case 16:
z := s.constFloat64(Types[TFLOAT64], 0)
return s.entryNewValue2(ssa.OpComplexMake, t, z, z)
default:
s.Fatalf("bad sized complex type %s", t)
}
case t.IsString():
return s.constEmptyString(t)
case t.IsPtrShaped():
return s.constNil(t)
case t.IsBoolean():
return s.constBool(false)
case t.IsInterface():
return s.constInterface(t)
case t.IsSlice():
return s.constSlice(t)
case t.IsStruct():
n := t.NumFields()
v := s.entryNewValue0(ssa.StructMakeOp(t.NumFields()), t)
for i := 0; i < n; i++ {
v.AddArg(s.zeroVal(t.FieldType(i).(*Type)))
}
return v
}
s.Unimplementedf("zero for type %v not implemented", t)
return nil
}
type callKind int8
const (
callNormal callKind = iota
callDefer
callGo
)
// isSSAIntrinsic1 returns true if n is a call to a recognized 1-arg intrinsic
// that can be handled by the SSA backend.
// SSA uses this, but so does the front end to see if should not
// inline a function because it is a candidate for intrinsic
// substitution.
func isSSAIntrinsic1(s *Sym) bool {
// The test below is not quite accurate -- in the event that
// a function is disabled on a per-function basis, for example
// because of hash-keyed binary failure search, SSA might be
// disabled for that function but it would not be noted here,
// and thus an inlining would not occur (in practice, inlining
// so far has only been noticed for Bswap32 and the 16-bit count
// leading/trailing instructions, but heuristics might change
// in the future or on different architectures).
if !ssaEnabled || ssa.IntrinsicsDisable || Thearch.LinkArch.Family != sys.AMD64 {
return false
}
if s != nil && s.Pkg != nil && s.Pkg.Path == "runtime/internal/sys" {
switch s.Name {
case
"Ctz64", "Ctz32", "Ctz16",
"Bswap64", "Bswap32":
return true
}
}
return false
}
func isIntrinsicCall1(n *Node) bool {
if n == nil || n.Left == nil {
return false
}
return isSSAIntrinsic1(n.Left.Sym)
}
// intrinsicFirstArg extracts arg from n.List and eval
func (s *state) intrinsicFirstArg(n *Node) *ssa.Value {
x := n.List.First()
if x.Op == OAS {
x = x.Right
}
return s.expr(x)
}
// intrinsicCall1 converts a call to a recognized 1-arg intrinsic
// into the intrinsic
func (s *state) intrinsicCall1(n *Node) *ssa.Value {
var result *ssa.Value
switch n.Left.Sym.Name {
case "Ctz64":
result = s.newValue1(ssa.OpCtz64, Types[TUINT64], s.intrinsicFirstArg(n))
case "Ctz32":
result = s.newValue1(ssa.OpCtz32, Types[TUINT32], s.intrinsicFirstArg(n))
case "Ctz16":
result = s.newValue1(ssa.OpCtz16, Types[TUINT16], s.intrinsicFirstArg(n))
case "Bswap64":
result = s.newValue1(ssa.OpBswap64, Types[TUINT64], s.intrinsicFirstArg(n))
case "Bswap32":
result = s.newValue1(ssa.OpBswap32, Types[TUINT32], s.intrinsicFirstArg(n))
}
if result == nil {
Fatalf("Unknown special call: %v", n.Left.Sym)
}
if ssa.IntrinsicsDebug > 0 {
Warnl(n.Lineno, "intrinsic substitution for %v with %s", n.Left.Sym.Name, result.LongString())
}
return result
}
// Calls the function n using the specified call type.
// Returns the address of the return value (or nil if none).
func (s *state) call(n *Node, k callKind) *ssa.Value {
var sym *Sym // target symbol (if static)
var closure *ssa.Value // ptr to closure to run (if dynamic)
var codeptr *ssa.Value // ptr to target code (if dynamic)
var rcvr *ssa.Value // receiver to set
fn := n.Left
switch n.Op {
case OCALLFUNC:
if k == callNormal && fn.Op == ONAME && fn.Class == PFUNC {
sym = fn.Sym
break
}
closure = s.expr(fn)
case OCALLMETH:
if fn.Op != ODOTMETH {
Fatalf("OCALLMETH: n.Left not an ODOTMETH: %v", fn)
}
if k == callNormal {
sym = fn.Sym
break
}
n2 := newname(fn.Sym)
n2.Class = PFUNC
n2.Lineno = fn.Lineno
closure = s.expr(n2)
// Note: receiver is already assigned in n.List, so we don't
// want to set it here.
case OCALLINTER:
if fn.Op != ODOTINTER {
Fatalf("OCALLINTER: n.Left not an ODOTINTER: %v", fn.Op)
}
i := s.expr(fn.Left)
itab := s.newValue1(ssa.OpITab, Types[TUINTPTR], i)
if k != callNormal {
s.nilCheck(itab)
}
itabidx := fn.Xoffset + 3*int64(Widthptr) + 8 // offset of fun field in runtime.itab
itab = s.newValue1I(ssa.OpOffPtr, Ptrto(Types[TUINTPTR]), itabidx, itab)
if k == callNormal {
codeptr = s.newValue2(ssa.OpLoad, Types[TUINTPTR], itab, s.mem())
} else {
closure = itab
}
rcvr = s.newValue1(ssa.OpIData, Types[TUINTPTR], i)
}
dowidth(fn.Type)
stksize := fn.Type.ArgWidth() // includes receiver
// Run all argument assignments. The arg slots have already
// been offset by the appropriate amount (+2*widthptr for go/defer,
// +widthptr for interface calls).
// For OCALLMETH, the receiver is set in these statements.
s.stmtList(n.List)
// Set receiver (for interface calls)
if rcvr != nil {
argStart := Ctxt.FixedFrameSize()
if k != callNormal {
argStart += int64(2 * Widthptr)
}
addr := s.entryNewValue1I(ssa.OpOffPtr, Ptrto(Types[TUINTPTR]), argStart, s.sp)
s.vars[&memVar] = s.newValue3I(ssa.OpStore, ssa.TypeMem, int64(Widthptr), addr, rcvr, s.mem())
}
// Defer/go args
if k != callNormal {
// Write argsize and closure (args to Newproc/Deferproc).
argStart := Ctxt.FixedFrameSize()
argsize := s.constInt32(Types[TUINT32], int32(stksize))
addr := s.entryNewValue1I(ssa.OpOffPtr, Ptrto(Types[TUINT32]), argStart, s.sp)
s.vars[&memVar] = s.newValue3I(ssa.OpStore, ssa.TypeMem, 4, addr, argsize, s.mem())
addr = s.entryNewValue1I(ssa.OpOffPtr, Ptrto(Types[TUINTPTR]), argStart+int64(Widthptr), s.sp)
s.vars[&memVar] = s.newValue3I(ssa.OpStore, ssa.TypeMem, int64(Widthptr), addr, closure, s.mem())
stksize += 2 * int64(Widthptr)
}
// call target
bNext := s.f.NewBlock(ssa.BlockPlain)
var call *ssa.Value
switch {
case k == callDefer:
call = s.newValue1(ssa.OpDeferCall, ssa.TypeMem, s.mem())
case k == callGo:
call = s.newValue1(ssa.OpGoCall, ssa.TypeMem, s.mem())
case closure != nil:
codeptr = s.newValue2(ssa.OpLoad, Types[TUINTPTR], closure, s.mem())
call = s.newValue3(ssa.OpClosureCall, ssa.TypeMem, codeptr, closure, s.mem())
case codeptr != nil:
call = s.newValue2(ssa.OpInterCall, ssa.TypeMem, codeptr, s.mem())
case sym != nil:
call = s.newValue1A(ssa.OpStaticCall, ssa.TypeMem, sym, s.mem())
default:
Fatalf("bad call type %s %v", n.Op, n)
}
call.AuxInt = stksize // Call operations carry the argsize of the callee along with them
// Finish call block
s.vars[&memVar] = call
b := s.endBlock()
b.Kind = ssa.BlockCall
b.SetControl(call)
b.AddEdgeTo(bNext)
if k == callDefer {
// Add recover edge to exit code.
b.Kind = ssa.BlockDefer
r := s.f.NewBlock(ssa.BlockPlain)
s.startBlock(r)
s.exit()
b.AddEdgeTo(r)
b.Likely = ssa.BranchLikely
}
// Start exit block, find address of result.
s.startBlock(bNext)
// Keep input pointer args live across calls. This is a bandaid until 1.8.
for _, n := range s.ptrargs {
s.vars[&memVar] = s.newValue2(ssa.OpKeepAlive, ssa.TypeMem, s.variable(n, n.Type), s.mem())
}
res := n.Left.Type.Results()
if res.NumFields() == 0 || k != callNormal {
// call has no return value. Continue with the next statement.
return nil
}
fp := res.Field(0)
return s.entryNewValue1I(ssa.OpOffPtr, Ptrto(fp.Type), fp.Offset+Ctxt.FixedFrameSize(), s.sp)
}
// etypesign returns the signed-ness of e, for integer/pointer etypes.
// -1 means signed, +1 means unsigned, 0 means non-integer/non-pointer.
func etypesign(e EType) int8 {
switch e {
case TINT8, TINT16, TINT32, TINT64, TINT:
return -1
case TUINT8, TUINT16, TUINT32, TUINT64, TUINT, TUINTPTR, TUNSAFEPTR:
return +1
}
return 0
}
// lookupSymbol is used to retrieve the symbol (Extern, Arg or Auto) used for a particular node.
// This improves the effectiveness of cse by using the same Aux values for the
// same symbols.
func (s *state) lookupSymbol(n *Node, sym interface{}) interface{} {
switch sym.(type) {
default:
s.Fatalf("sym %v is of uknown type %T", sym, sym)
case *ssa.ExternSymbol, *ssa.ArgSymbol, *ssa.AutoSymbol:
// these are the only valid types
}
if lsym, ok := s.varsyms[n]; ok {
return lsym
} else {
s.varsyms[n] = sym
return sym
}
}
// addr converts the address of the expression n to SSA, adds it to s and returns the SSA result.
// Also returns a bool reporting whether the returned value is "volatile", that is it
// points to the outargs section and thus the referent will be clobbered by any call.
// The value that the returned Value represents is guaranteed to be non-nil.
// If bounded is true then this address does not require a nil check for its operand
// even if that would otherwise be implied.
func (s *state) addr(n *Node, bounded bool) (*ssa.Value, bool) {
t := Ptrto(n.Type)
switch n.Op {
case ONAME:
switch n.Class {
case PEXTERN:
// global variable
aux := s.lookupSymbol(n, &ssa.ExternSymbol{Typ: n.Type, Sym: n.Sym})
v := s.entryNewValue1A(ssa.OpAddr, t, aux, s.sb)
// TODO: Make OpAddr use AuxInt as well as Aux.
if n.Xoffset != 0 {
v = s.entryNewValue1I(ssa.OpOffPtr, v.Type, n.Xoffset, v)
}
return v, false
case PPARAM:
// parameter slot
v := s.decladdrs[n]
if v != nil {
return v, false
}
if n.String() == ".fp" {
// Special arg that points to the frame pointer.
// (Used by the race detector, others?)
aux := s.lookupSymbol(n, &ssa.ArgSymbol{Typ: n.Type, Node: n})
return s.entryNewValue1A(ssa.OpAddr, t, aux, s.sp), false
}
s.Fatalf("addr of undeclared ONAME %v. declared: %v", n, s.decladdrs)
return nil, false
case PAUTO:
aux := s.lookupSymbol(n, &ssa.AutoSymbol{Typ: n.Type, Node: n})
return s.newValue1A(ssa.OpAddr, t, aux, s.sp), false
case PPARAMOUT: // Same as PAUTO -- cannot generate LEA early.
// ensure that we reuse symbols for out parameters so
// that cse works on their addresses
aux := s.lookupSymbol(n, &ssa.ArgSymbol{Typ: n.Type, Node: n})
return s.newValue1A(ssa.OpAddr, t, aux, s.sp), false
default:
s.Unimplementedf("variable address class %v not implemented", classnames[n.Class])
return nil, false
}
case OINDREG:
// indirect off a register
// used for storing/loading arguments/returns to/from callees
if int(n.Reg) != Thearch.REGSP {
s.Unimplementedf("OINDREG of non-SP register %s in addr: %v", obj.Rconv(int(n.Reg)), n)
return nil, false
}
return s.entryNewValue1I(ssa.OpOffPtr, t, n.Xoffset, s.sp), true
case OINDEX:
if n.Left.Type.IsSlice() {
a := s.expr(n.Left)
i := s.expr(n.Right)
i = s.extendIndex(i, Panicindex)
len := s.newValue1(ssa.OpSliceLen, Types[TINT], a)
if !n.Bounded {
s.boundsCheck(i, len)
}
p := s.newValue1(ssa.OpSlicePtr, t, a)
return s.newValue2(ssa.OpPtrIndex, t, p, i), false
} else { // array
a, isVolatile := s.addr(n.Left, bounded)
i := s.expr(n.Right)
i = s.extendIndex(i, Panicindex)
len := s.constInt(Types[TINT], n.Left.Type.NumElem())
if !n.Bounded {
s.boundsCheck(i, len)
}
return s.newValue2(ssa.OpPtrIndex, Ptrto(n.Left.Type.Elem()), a, i), isVolatile
}
case OIND:
return s.exprPtr(n.Left, bounded, n.Lineno), false
case ODOT:
p, isVolatile := s.addr(n.Left, bounded)
return s.newValue1I(ssa.OpOffPtr, t, n.Xoffset, p), isVolatile
case ODOTPTR:
p := s.exprPtr(n.Left, bounded, n.Lineno)
return s.newValue1I(ssa.OpOffPtr, t, n.Xoffset, p), false
case OCLOSUREVAR:
return s.newValue1I(ssa.OpOffPtr, t, n.Xoffset,
s.entryNewValue0(ssa.OpGetClosurePtr, Ptrto(Types[TUINT8]))), false
case OCONVNOP:
addr, isVolatile := s.addr(n.Left, bounded)
return s.newValue1(ssa.OpCopy, t, addr), isVolatile // ensure that addr has the right type
case OCALLFUNC, OCALLINTER, OCALLMETH:
return s.call(n, callNormal), true
default:
s.Unimplementedf("unhandled addr %v", n.Op)
return nil, false
}
}
// canSSA reports whether n is SSA-able.
// n must be an ONAME (or an ODOT sequence with an ONAME base).
func (s *state) canSSA(n *Node) bool {
if Debug['N'] != 0 {
return false
}
for n.Op == ODOT {
n = n.Left
}
if n.Op != ONAME {
return false
}
if n.Addrtaken {
return false
}
if n.isParamHeapCopy() {
return false
}
if n.Class == PAUTOHEAP {
Fatalf("canSSA of PAUTOHEAP %v", n)
}
switch n.Class {
case PEXTERN:
return false
case PPARAMOUT:
if hasdefer {
// TODO: handle this case? Named return values must be
// in memory so that the deferred function can see them.
// Maybe do: if !strings.HasPrefix(n.String(), "~") { return false }
return false
}
if s.cgoUnsafeArgs {
// Cgo effectively takes the address of all result args,
// but the compiler can't see that.
return false
}
}
if n.Class == PPARAM && n.String() == ".this" {
// wrappers generated by genwrapper need to update
// the .this pointer in place.
// TODO: treat as a PPARMOUT?
return false
}
return canSSAType(n.Type)
// TODO: try to make more variables SSAable?
}
// canSSA reports whether variables of type t are SSA-able.
func canSSAType(t *Type) bool {
dowidth(t)
if t.Width > int64(4*Widthptr) {
// 4*Widthptr is an arbitrary constant. We want it
// to be at least 3*Widthptr so slices can be registerized.
// Too big and we'll introduce too much register pressure.
return false
}
switch t.Etype {
case TARRAY:
// We can't do arrays because dynamic indexing is
// not supported on SSA variables.
// TODO: maybe allow if length is <=1? All indexes
// are constant? Might be good for the arrays
// introduced by the compiler for variadic functions.
return false
case TSTRUCT:
if t.NumFields() > ssa.MaxStruct {
return false
}
for _, t1 := range t.Fields().Slice() {
if !canSSAType(t1.Type) {
return false
}
}
return true
default:
return true
}
}
// exprPtr evaluates n to a pointer and nil-checks it.
func (s *state) exprPtr(n *Node, bounded bool, lineno int32) *ssa.Value {
p := s.expr(n)
if bounded || n.NonNil {
if s.f.Config.Debug_checknil() && lineno > 1 {
s.f.Config.Warnl(lineno, "removed nil check")
}
return p
}
s.nilCheck(p)
return p
}
// nilCheck generates nil pointer checking code.
// Starts a new block on return, unless nil checks are disabled.
// Used only for automatically inserted nil checks,
// not for user code like 'x != nil'.
func (s *state) nilCheck(ptr *ssa.Value) {
if Disable_checknil != 0 {
return
}
chk := s.newValue2(ssa.OpNilCheck, ssa.TypeVoid, ptr, s.mem())
b := s.endBlock()
b.Kind = ssa.BlockCheck
b.SetControl(chk)
bNext := s.f.NewBlock(ssa.BlockPlain)
b.AddEdgeTo(bNext)
s.startBlock(bNext)
}
// boundsCheck generates bounds checking code. Checks if 0 <= idx < len, branches to exit if not.
// Starts a new block on return.
// idx is already converted to full int width.
func (s *state) boundsCheck(idx, len *ssa.Value) {
if Debug['B'] != 0 {
return
}
// bounds check
cmp := s.newValue2(ssa.OpIsInBounds, Types[TBOOL], idx, len)
s.check(cmp, Panicindex)
}
// sliceBoundsCheck generates slice bounds checking code. Checks if 0 <= idx <= len, branches to exit if not.
// Starts a new block on return.
// idx and len are already converted to full int width.
func (s *state) sliceBoundsCheck(idx, len *ssa.Value) {
if Debug['B'] != 0 {
return
}
// bounds check
cmp := s.newValue2(ssa.OpIsSliceInBounds, Types[TBOOL], idx, len)
s.check(cmp, panicslice)
}
// If cmp (a bool) is false, panic using the given function.
func (s *state) check(cmp *ssa.Value, fn *Node) {
b := s.endBlock()
b.Kind = ssa.BlockIf
b.SetControl(cmp)
b.Likely = ssa.BranchLikely
bNext := s.f.NewBlock(ssa.BlockPlain)
line := s.peekLine()
bPanic := s.panics[funcLine{fn, line}]
if bPanic == nil {
bPanic = s.f.NewBlock(ssa.BlockPlain)
s.panics[funcLine{fn, line}] = bPanic
s.startBlock(bPanic)
// The panic call takes/returns memory to ensure that the right
// memory state is observed if the panic happens.
s.rtcall(fn, false, nil)
}
b.AddEdgeTo(bNext)
b.AddEdgeTo(bPanic)
s.startBlock(bNext)
}
// rtcall issues a call to the given runtime function fn with the listed args.
// Returns a slice of results of the given result types.
// The call is added to the end of the current block.
// If returns is false, the block is marked as an exit block.
// If returns is true, the block is marked as a call block. A new block
// is started to load the return values.
func (s *state) rtcall(fn *Node, returns bool, results []*Type, args ...*ssa.Value) []*ssa.Value {
// Write args to the stack
off := Ctxt.FixedFrameSize()
for _, arg := range args {
t := arg.Type
off = Rnd(off, t.Alignment())
ptr := s.sp
if off != 0 {
ptr = s.newValue1I(ssa.OpOffPtr, t.PtrTo(), off, s.sp)
}
size := t.Size()
s.vars[&memVar] = s.newValue3I(ssa.OpStore, ssa.TypeMem, size, ptr, arg, s.mem())
off += size
}
off = Rnd(off, int64(Widthptr))
if Thearch.LinkArch.Name == "amd64p32" {
// amd64p32 wants 8-byte alignment of the start of the return values.
off = Rnd(off, 8)
}
// Issue call
call := s.newValue1A(ssa.OpStaticCall, ssa.TypeMem, fn.Sym, s.mem())
s.vars[&memVar] = call
// Finish block
b := s.endBlock()
if !returns {
b.Kind = ssa.BlockExit
b.SetControl(call)
call.AuxInt = off - Ctxt.FixedFrameSize()
if len(results) > 0 {
Fatalf("panic call can't have results")
}
return nil
}
b.Kind = ssa.BlockCall
b.SetControl(call)
bNext := s.f.NewBlock(ssa.BlockPlain)
b.AddEdgeTo(bNext)
s.startBlock(bNext)
// Keep input pointer args live across calls. This is a bandaid until 1.8.
for _, n := range s.ptrargs {
s.vars[&memVar] = s.newValue2(ssa.OpKeepAlive, ssa.TypeMem, s.variable(n, n.Type), s.mem())
}
// Load results
res := make([]*ssa.Value, len(results))
for i, t := range results {
off = Rnd(off, t.Alignment())
ptr := s.sp
if off != 0 {
ptr = s.newValue1I(ssa.OpOffPtr, Ptrto(t), off, s.sp)
}
res[i] = s.newValue2(ssa.OpLoad, t, ptr, s.mem())
off += t.Size()
}
off = Rnd(off, int64(Widthptr))
// Remember how much callee stack space we needed.
call.AuxInt = off
return res
}
// insertWBmove inserts the assignment *left = *right including a write barrier.
// t is the type being assigned.
func (s *state) insertWBmove(t *Type, left, right *ssa.Value, line int32, rightIsVolatile bool) {
// if writeBarrier.enabled {
// typedmemmove(&t, left, right)
// } else {
// *left = *right
// }
if s.noWB {
s.Fatalf("write barrier prohibited")
}
if s.WBLineno == 0 {
s.WBLineno = left.Line
}
bThen := s.f.NewBlock(ssa.BlockPlain)
bElse := s.f.NewBlock(ssa.BlockPlain)
bEnd := s.f.NewBlock(ssa.BlockPlain)
aux := &ssa.ExternSymbol{Typ: Types[TBOOL], Sym: syslook("writeBarrier").Sym}
flagaddr := s.newValue1A(ssa.OpAddr, Ptrto(Types[TUINT32]), aux, s.sb)
// Load word, test word, avoiding partial register write from load byte.
flag := s.newValue2(ssa.OpLoad, Types[TUINT32], flagaddr, s.mem())
flag = s.newValue2(ssa.OpNeq32, Types[TBOOL], flag, s.constInt32(Types[TUINT32], 0))
b := s.endBlock()
b.Kind = ssa.BlockIf
b.Likely = ssa.BranchUnlikely
b.SetControl(flag)
b.AddEdgeTo(bThen)
b.AddEdgeTo(bElse)
s.startBlock(bThen)
if !rightIsVolatile {
// Issue typedmemmove call.
taddr := s.newValue1A(ssa.OpAddr, Types[TUINTPTR], &ssa.ExternSymbol{Typ: Types[TUINTPTR], Sym: typenamesym(t)}, s.sb)
s.rtcall(typedmemmove, true, nil, taddr, left, right)
} else {
// Copy to temp location if the source is volatile (will be clobbered by
// a function call). Marshaling the args to typedmemmove might clobber the
// value we're trying to move.
tmp := temp(t)
s.vars[&memVar] = s.newValue1A(ssa.OpVarDef, ssa.TypeMem, tmp, s.mem())
tmpaddr, _ := s.addr(tmp, true)
s.vars[&memVar] = s.newValue3I(ssa.OpMove, ssa.TypeMem, SizeAlignAuxInt(t), tmpaddr, right, s.mem())
// Issue typedmemmove call.
taddr := s.newValue1A(ssa.OpAddr, Types[TUINTPTR], &ssa.ExternSymbol{Typ: Types[TUINTPTR], Sym: typenamesym(t)}, s.sb)
s.rtcall(typedmemmove, true, nil, taddr, left, tmpaddr)
// Mark temp as dead.
s.vars[&memVar] = s.newValue1A(ssa.OpVarKill, ssa.TypeMem, tmp, s.mem())
}
s.endBlock().AddEdgeTo(bEnd)
s.startBlock(bElse)
s.vars[&memVar] = s.newValue3I(ssa.OpMove, ssa.TypeMem, SizeAlignAuxInt(t), left, right, s.mem())
s.endBlock().AddEdgeTo(bEnd)
s.startBlock(bEnd)
if Debug_wb > 0 {
Warnl(line, "write barrier")
}
}
// insertWBstore inserts the assignment *left = right including a write barrier.
// t is the type being assigned.
func (s *state) insertWBstore(t *Type, left, right *ssa.Value, line int32, skip skipMask) {
// store scalar fields
// if writeBarrier.enabled {
// writebarrierptr for pointer fields
// } else {
// store pointer fields
// }
if s.noWB {
s.Fatalf("write barrier prohibited")
}
if s.WBLineno == 0 {
s.WBLineno = left.Line
}
s.storeTypeScalars(t, left, right, skip)
bThen := s.f.NewBlock(ssa.BlockPlain)
bElse := s.f.NewBlock(ssa.BlockPlain)
bEnd := s.f.NewBlock(ssa.BlockPlain)
aux := &ssa.ExternSymbol{Typ: Types[TBOOL], Sym: syslook("writeBarrier").Sym}
flagaddr := s.newValue1A(ssa.OpAddr, Ptrto(Types[TUINT32]), aux, s.sb)
// Load word, test word, avoiding partial register write from load byte.
flag := s.newValue2(ssa.OpLoad, Types[TUINT32], flagaddr, s.mem())
flag = s.newValue2(ssa.OpNeq32, Types[TBOOL], flag, s.constInt32(Types[TUINT32], 0))
b := s.endBlock()
b.Kind = ssa.BlockIf
b.Likely = ssa.BranchUnlikely
b.SetControl(flag)
b.AddEdgeTo(bThen)
b.AddEdgeTo(bElse)
// Issue write barriers for pointer writes.
s.startBlock(bThen)
s.storeTypePtrsWB(t, left, right)
s.endBlock().AddEdgeTo(bEnd)
// Issue regular stores for pointer writes.
s.startBlock(bElse)
s.storeTypePtrs(t, left, right)
s.endBlock().AddEdgeTo(bEnd)
s.startBlock(bEnd)
if Debug_wb > 0 {
Warnl(line, "write barrier")
}
}
// do *left = right for all scalar (non-pointer) parts of t.
func (s *state) storeTypeScalars(t *Type, left, right *ssa.Value, skip skipMask) {
switch {
case t.IsBoolean() || t.IsInteger() || t.IsFloat() || t.IsComplex():
s.vars[&memVar] = s.newValue3I(ssa.OpStore, ssa.TypeMem, t.Size(), left, right, s.mem())
case t.IsPtrShaped():
// no scalar fields.
case t.IsString():
if skip&skipLen != 0 {
return
}
len := s.newValue1(ssa.OpStringLen, Types[TINT], right)
lenAddr := s.newValue1I(ssa.OpOffPtr, Ptrto(Types[TINT]), s.config.IntSize, left)
s.vars[&memVar] = s.newValue3I(ssa.OpStore, ssa.TypeMem, s.config.IntSize, lenAddr, len, s.mem())
case t.IsSlice():
if skip&skipLen == 0 {
len := s.newValue1(ssa.OpSliceLen, Types[TINT], right)
lenAddr := s.newValue1I(ssa.OpOffPtr, Ptrto(Types[TINT]), s.config.IntSize, left)
s.vars[&memVar] = s.newValue3I(ssa.OpStore, ssa.TypeMem, s.config.IntSize, lenAddr, len, s.mem())
}
if skip&skipCap == 0 {
cap := s.newValue1(ssa.OpSliceCap, Types[TINT], right)
capAddr := s.newValue1I(ssa.OpOffPtr, Ptrto(Types[TINT]), 2*s.config.IntSize, left)
s.vars[&memVar] = s.newValue3I(ssa.OpStore, ssa.TypeMem, s.config.IntSize, capAddr, cap, s.mem())
}
case t.IsInterface():
// itab field doesn't need a write barrier (even though it is a pointer).
itab := s.newValue1(ssa.OpITab, Ptrto(Types[TUINT8]), right)
s.vars[&memVar] = s.newValue3I(ssa.OpStore, ssa.TypeMem, s.config.IntSize, left, itab, s.mem())
case t.IsStruct():
n := t.NumFields()
for i := 0; i < n; i++ {
ft := t.FieldType(i)
addr := s.newValue1I(ssa.OpOffPtr, ft.PtrTo(), t.FieldOff(i), left)
val := s.newValue1I(ssa.OpStructSelect, ft, int64(i), right)
s.storeTypeScalars(ft.(*Type), addr, val, 0)
}
default:
s.Fatalf("bad write barrier type %s", t)
}
}
// do *left = right for all pointer parts of t.
func (s *state) storeTypePtrs(t *Type, left, right *ssa.Value) {
switch {
case t.IsPtrShaped():
s.vars[&memVar] = s.newValue3I(ssa.OpStore, ssa.TypeMem, s.config.PtrSize, left, right, s.mem())
case t.IsString():
ptr := s.newValue1(ssa.OpStringPtr, Ptrto(Types[TUINT8]), right)
s.vars[&memVar] = s.newValue3I(ssa.OpStore, ssa.TypeMem, s.config.PtrSize, left, ptr, s.mem())
case t.IsSlice():
ptr := s.newValue1(ssa.OpSlicePtr, Ptrto(Types[TUINT8]), right)
s.vars[&memVar] = s.newValue3I(ssa.OpStore, ssa.TypeMem, s.config.PtrSize, left, ptr, s.mem())
case t.IsInterface():
// itab field is treated as a scalar.
idata := s.newValue1(ssa.OpIData, Ptrto(Types[TUINT8]), right)
idataAddr := s.newValue1I(ssa.OpOffPtr, Ptrto(Types[TUINT8]), s.config.PtrSize, left)
s.vars[&memVar] = s.newValue3I(ssa.OpStore, ssa.TypeMem, s.config.PtrSize, idataAddr, idata, s.mem())
case t.IsStruct():
n := t.NumFields()
for i := 0; i < n; i++ {
ft := t.FieldType(i)
if !haspointers(ft.(*Type)) {
continue
}
addr := s.newValue1I(ssa.OpOffPtr, ft.PtrTo(), t.FieldOff(i), left)
val := s.newValue1I(ssa.OpStructSelect, ft, int64(i), right)
s.storeTypePtrs(ft.(*Type), addr, val)
}
default:
s.Fatalf("bad write barrier type %s", t)
}
}
// do *left = right with a write barrier for all pointer parts of t.
func (s *state) storeTypePtrsWB(t *Type, left, right *ssa.Value) {
switch {
case t.IsPtrShaped():
s.rtcall(writebarrierptr, true, nil, left, right)
case t.IsString():
ptr := s.newValue1(ssa.OpStringPtr, Ptrto(Types[TUINT8]), right)
s.rtcall(writebarrierptr, true, nil, left, ptr)
case t.IsSlice():
ptr := s.newValue1(ssa.OpSlicePtr, Ptrto(Types[TUINT8]), right)
s.rtcall(writebarrierptr, true, nil, left, ptr)
case t.IsInterface():
idata := s.newValue1(ssa.OpIData, Ptrto(Types[TUINT8]), right)
idataAddr := s.newValue1I(ssa.OpOffPtr, Ptrto(Types[TUINT8]), s.config.PtrSize, left)
s.rtcall(writebarrierptr, true, nil, idataAddr, idata)
case t.IsStruct():
n := t.NumFields()
for i := 0; i < n; i++ {
ft := t.FieldType(i)
if !haspointers(ft.(*Type)) {
continue
}
addr := s.newValue1I(ssa.OpOffPtr, ft.PtrTo(), t.FieldOff(i), left)
val := s.newValue1I(ssa.OpStructSelect, ft, int64(i), right)
s.storeTypePtrsWB(ft.(*Type), addr, val)
}
default:
s.Fatalf("bad write barrier type %s", t)
}
}
// slice computes the slice v[i:j:k] and returns ptr, len, and cap of result.
// i,j,k may be nil, in which case they are set to their default value.
// t is a slice, ptr to array, or string type.
func (s *state) slice(t *Type, v, i, j, k *ssa.Value) (p, l, c *ssa.Value) {
var elemtype *Type
var ptrtype *Type
var ptr *ssa.Value
var len *ssa.Value
var cap *ssa.Value
zero := s.constInt(Types[TINT], 0)
switch {
case t.IsSlice():
elemtype = t.Elem()
ptrtype = Ptrto(elemtype)
ptr = s.newValue1(ssa.OpSlicePtr, ptrtype, v)
len = s.newValue1(ssa.OpSliceLen, Types[TINT], v)
cap = s.newValue1(ssa.OpSliceCap, Types[TINT], v)
case t.IsString():
elemtype = Types[TUINT8]
ptrtype = Ptrto(elemtype)
ptr = s.newValue1(ssa.OpStringPtr, ptrtype, v)
len = s.newValue1(ssa.OpStringLen, Types[TINT], v)
cap = len
case t.IsPtr():
if !t.Elem().IsArray() {
s.Fatalf("bad ptr to array in slice %v\n", t)
}
elemtype = t.Elem().Elem()
ptrtype = Ptrto(elemtype)
s.nilCheck(v)
ptr = v
len = s.constInt(Types[TINT], t.Elem().NumElem())
cap = len
default:
s.Fatalf("bad type in slice %v\n", t)
}
// Set default values
if i == nil {
i = zero
}
if j == nil {
j = len
}
if k == nil {
k = cap
}
// Panic if slice indices are not in bounds.
s.sliceBoundsCheck(i, j)
if j != k {
s.sliceBoundsCheck(j, k)
}
if k != cap {
s.sliceBoundsCheck(k, cap)
}
// Generate the following code assuming that indexes are in bounds.
// The conditional is to make sure that we don't generate a slice
// that points to the next object in memory.
// rlen = j-i
// rcap = k-i
// delta = i*elemsize
// if rcap == 0 {
// delta = 0
// }
// rptr = p+delta
// result = (SliceMake rptr rlen rcap)
subOp := s.ssaOp(OSUB, Types[TINT])
eqOp := s.ssaOp(OEQ, Types[TINT])
mulOp := s.ssaOp(OMUL, Types[TINT])
rlen := s.newValue2(subOp, Types[TINT], j, i)
var rcap *ssa.Value
switch {
case t.IsString():
// Capacity of the result is unimportant. However, we use
// rcap to test if we've generated a zero-length slice.
// Use length of strings for that.
rcap = rlen
case j == k:
rcap = rlen
default:
rcap = s.newValue2(subOp, Types[TINT], k, i)
}
// delta = # of elements to offset pointer by.
s.vars[&deltaVar] = i
// Generate code to set delta=0 if the resulting capacity is zero.
if !((i.Op == ssa.OpConst64 && i.AuxInt == 0) ||
(i.Op == ssa.OpConst32 && int32(i.AuxInt) == 0)) {
cmp := s.newValue2(eqOp, Types[TBOOL], rcap, zero)
b := s.endBlock()
b.Kind = ssa.BlockIf
b.Likely = ssa.BranchUnlikely
b.SetControl(cmp)
// Generate block which zeros the delta variable.
nz := s.f.NewBlock(ssa.BlockPlain)
b.AddEdgeTo(nz)
s.startBlock(nz)
s.vars[&deltaVar] = zero
s.endBlock()
// All done.
merge := s.f.NewBlock(ssa.BlockPlain)
b.AddEdgeTo(merge)
nz.AddEdgeTo(merge)
s.startBlock(merge)
// TODO: use conditional moves somehow?
}
// Compute rptr = ptr + delta * elemsize
rptr := s.newValue2(ssa.OpAddPtr, ptrtype, ptr, s.newValue2(mulOp, Types[TINT], s.variable(&deltaVar, Types[TINT]), s.constInt(Types[TINT], elemtype.Width)))
delete(s.vars, &deltaVar)
return rptr, rlen, rcap
}
type u2fcvtTab struct {
geq, cvt2F, and, rsh, or, add ssa.Op
one func(*state, ssa.Type, int64) *ssa.Value
}
var u64_f64 u2fcvtTab = u2fcvtTab{
geq: ssa.OpGeq64,
cvt2F: ssa.OpCvt64to64F,
and: ssa.OpAnd64,
rsh: ssa.OpRsh64Ux64,
or: ssa.OpOr64,
add: ssa.OpAdd64F,
one: (*state).constInt64,
}
var u64_f32 u2fcvtTab = u2fcvtTab{
geq: ssa.OpGeq64,
cvt2F: ssa.OpCvt64to32F,
and: ssa.OpAnd64,
rsh: ssa.OpRsh64Ux64,
or: ssa.OpOr64,
add: ssa.OpAdd32F,
one: (*state).constInt64,
}
// Excess generality on a machine with 64-bit integer registers.
// Not used on AMD64.
var u32_f32 u2fcvtTab = u2fcvtTab{
geq: ssa.OpGeq32,
cvt2F: ssa.OpCvt32to32F,
and: ssa.OpAnd32,
rsh: ssa.OpRsh32Ux32,
or: ssa.OpOr32,
add: ssa.OpAdd32F,
one: func(s *state, t ssa.Type, x int64) *ssa.Value {
return s.constInt32(t, int32(x))
},
}
func (s *state) uint64Tofloat64(n *Node, x *ssa.Value, ft, tt *Type) *ssa.Value {
return s.uintTofloat(&u64_f64, n, x, ft, tt)
}
func (s *state) uint64Tofloat32(n *Node, x *ssa.Value, ft, tt *Type) *ssa.Value {
return s.uintTofloat(&u64_f32, n, x, ft, tt)
}
func (s *state) uintTofloat(cvttab *u2fcvtTab, n *Node, x *ssa.Value, ft, tt *Type) *ssa.Value {
// if x >= 0 {
// result = (floatY) x
// } else {
// y = uintX(x) ; y = x & 1
// z = uintX(x) ; z = z >> 1
// z = z >> 1
// z = z | y
// result = floatY(z)
// result = result + result
// }
//
// Code borrowed from old code generator.
// What's going on: large 64-bit "unsigned" looks like
// negative number to hardware's integer-to-float
// conversion. However, because the mantissa is only
// 63 bits, we don't need the LSB, so instead we do an
// unsigned right shift (divide by two), convert, and
// double. However, before we do that, we need to be
// sure that we do not lose a "1" if that made the
// difference in the resulting rounding. Therefore, we
// preserve it, and OR (not ADD) it back in. The case
// that matters is when the eleven discarded bits are
// equal to 10000000001; that rounds up, and the 1 cannot
// be lost else it would round down if the LSB of the
// candidate mantissa is 0.
cmp := s.newValue2(cvttab.geq, Types[TBOOL], x, s.zeroVal(ft))
b := s.endBlock()
b.Kind = ssa.BlockIf
b.SetControl(cmp)
b.Likely = ssa.BranchLikely
bThen := s.f.NewBlock(ssa.BlockPlain)
bElse := s.f.NewBlock(ssa.BlockPlain)
bAfter := s.f.NewBlock(ssa.BlockPlain)
b.AddEdgeTo(bThen)
s.startBlock(bThen)
a0 := s.newValue1(cvttab.cvt2F, tt, x)
s.vars[n] = a0
s.endBlock()
bThen.AddEdgeTo(bAfter)
b.AddEdgeTo(bElse)
s.startBlock(bElse)
one := cvttab.one(s, ft, 1)
y := s.newValue2(cvttab.and, ft, x, one)
z := s.newValue2(cvttab.rsh, ft, x, one)
z = s.newValue2(cvttab.or, ft, z, y)
a := s.newValue1(cvttab.cvt2F, tt, z)
a1 := s.newValue2(cvttab.add, tt, a, a)
s.vars[n] = a1
s.endBlock()
bElse.AddEdgeTo(bAfter)
s.startBlock(bAfter)
return s.variable(n, n.Type)
}
// referenceTypeBuiltin generates code for the len/cap builtins for maps and channels.
func (s *state) referenceTypeBuiltin(n *Node, x *ssa.Value) *ssa.Value {
if !n.Left.Type.IsMap() && !n.Left.Type.IsChan() {
s.Fatalf("node must be a map or a channel")
}
// if n == nil {
// return 0
// } else {
// // len
// return *((*int)n)
// // cap
// return *(((*int)n)+1)
// }
lenType := n.Type
nilValue := s.constNil(Types[TUINTPTR])
cmp := s.newValue2(ssa.OpEqPtr, Types[TBOOL], x, nilValue)
b := s.endBlock()
b.Kind = ssa.BlockIf
b.SetControl(cmp)
b.Likely = ssa.BranchUnlikely
bThen := s.f.NewBlock(ssa.BlockPlain)
bElse := s.f.NewBlock(ssa.BlockPlain)
bAfter := s.f.NewBlock(ssa.BlockPlain)
// length/capacity of a nil map/chan is zero
b.AddEdgeTo(bThen)
s.startBlock(bThen)
s.vars[n] = s.zeroVal(lenType)
s.endBlock()
bThen.AddEdgeTo(bAfter)
b.AddEdgeTo(bElse)
s.startBlock(bElse)
if n.Op == OLEN {
// length is stored in the first word for map/chan
s.vars[n] = s.newValue2(ssa.OpLoad, lenType, x, s.mem())
} else if n.Op == OCAP {
// capacity is stored in the second word for chan
sw := s.newValue1I(ssa.OpOffPtr, lenType.PtrTo(), lenType.Width, x)
s.vars[n] = s.newValue2(ssa.OpLoad, lenType, sw, s.mem())
} else {
s.Fatalf("op must be OLEN or OCAP")
}
s.endBlock()
bElse.AddEdgeTo(bAfter)
s.startBlock(bAfter)
return s.variable(n, lenType)
}
type f2uCvtTab struct {
ltf, cvt2U, subf ssa.Op
value func(*state, ssa.Type, float64) *ssa.Value
}
var f32_u64 f2uCvtTab = f2uCvtTab{
ltf: ssa.OpLess32F,
cvt2U: ssa.OpCvt32Fto64,
subf: ssa.OpSub32F,
value: (*state).constFloat32,
}
var f64_u64 f2uCvtTab = f2uCvtTab{
ltf: ssa.OpLess64F,
cvt2U: ssa.OpCvt64Fto64,
subf: ssa.OpSub64F,
value: (*state).constFloat64,
}
func (s *state) float32ToUint64(n *Node, x *ssa.Value, ft, tt *Type) *ssa.Value {
return s.floatToUint(&f32_u64, n, x, ft, tt)
}
func (s *state) float64ToUint64(n *Node, x *ssa.Value, ft, tt *Type) *ssa.Value {
return s.floatToUint(&f64_u64, n, x, ft, tt)
}
func (s *state) floatToUint(cvttab *f2uCvtTab, n *Node, x *ssa.Value, ft, tt *Type) *ssa.Value {
// if x < 9223372036854775808.0 {
// result = uintY(x)
// } else {
// y = x - 9223372036854775808.0
// z = uintY(y)
// result = z | -9223372036854775808
// }
twoToThe63 := cvttab.value(s, ft, 9223372036854775808.0)
cmp := s.newValue2(cvttab.ltf, Types[TBOOL], x, twoToThe63)
b := s.endBlock()
b.Kind = ssa.BlockIf
b.SetControl(cmp)
b.Likely = ssa.BranchLikely
bThen := s.f.NewBlock(ssa.BlockPlain)
bElse := s.f.NewBlock(ssa.BlockPlain)
bAfter := s.f.NewBlock(ssa.BlockPlain)
b.AddEdgeTo(bThen)
s.startBlock(bThen)
a0 := s.newValue1(cvttab.cvt2U, tt, x)
s.vars[n] = a0
s.endBlock()
bThen.AddEdgeTo(bAfter)
b.AddEdgeTo(bElse)
s.startBlock(bElse)
y := s.newValue2(cvttab.subf, ft, x, twoToThe63)
y = s.newValue1(cvttab.cvt2U, tt, y)
z := s.constInt64(tt, -9223372036854775808)
a1 := s.newValue2(ssa.OpOr64, tt, y, z)
s.vars[n] = a1
s.endBlock()
bElse.AddEdgeTo(bAfter)
s.startBlock(bAfter)
return s.variable(n, n.Type)
}
// ifaceType returns the value for the word containing the type.
// n is the node for the interface expression.
// v is the corresponding value.
func (s *state) ifaceType(n *Node, v *ssa.Value) *ssa.Value {
byteptr := Ptrto(Types[TUINT8]) // type used in runtime prototypes for runtime type (*byte)
if n.Type.IsEmptyInterface() {
// Have *eface. The type is the first word in the struct.
return s.newValue1(ssa.OpITab, byteptr, v)
}
// Have *iface.
// The first word in the struct is the *itab.
// If the *itab is nil, return 0.
// Otherwise, the second word in the *itab is the type.
tab := s.newValue1(ssa.OpITab, byteptr, v)
s.vars[&typVar] = tab
isnonnil := s.newValue2(ssa.OpNeqPtr, Types[TBOOL], tab, s.constNil(byteptr))
b := s.endBlock()
b.Kind = ssa.BlockIf
b.SetControl(isnonnil)
b.Likely = ssa.BranchLikely
bLoad := s.f.NewBlock(ssa.BlockPlain)
bEnd := s.f.NewBlock(ssa.BlockPlain)
b.AddEdgeTo(bLoad)
b.AddEdgeTo(bEnd)
bLoad.AddEdgeTo(bEnd)
s.startBlock(bLoad)
off := s.newValue1I(ssa.OpOffPtr, byteptr, int64(Widthptr), tab)
s.vars[&typVar] = s.newValue2(ssa.OpLoad, byteptr, off, s.mem())
s.endBlock()
s.startBlock(bEnd)
typ := s.variable(&typVar, byteptr)
delete(s.vars, &typVar)
return typ
}
// dottype generates SSA for a type assertion node.
// commaok indicates whether to panic or return a bool.
// If commaok is false, resok will be nil.
func (s *state) dottype(n *Node, commaok bool) (res, resok *ssa.Value) {
iface := s.expr(n.Left)
typ := s.ifaceType(n.Left, iface) // actual concrete type
target := s.expr(typename(n.Type)) // target type
if !isdirectiface(n.Type) {
// walk rewrites ODOTTYPE/OAS2DOTTYPE into runtime calls except for this case.
Fatalf("dottype needs a direct iface type %s", n.Type)
}
if Debug_typeassert > 0 {
Warnl(n.Lineno, "type assertion inlined")
}
// TODO: If we have a nonempty interface and its itab field is nil,
// then this test is redundant and ifaceType should just branch directly to bFail.
cond := s.newValue2(ssa.OpEqPtr, Types[TBOOL], typ, target)
b := s.endBlock()
b.Kind = ssa.BlockIf
b.SetControl(cond)
b.Likely = ssa.BranchLikely
byteptr := Ptrto(Types[TUINT8])
bOk := s.f.NewBlock(ssa.BlockPlain)
bFail := s.f.NewBlock(ssa.BlockPlain)
b.AddEdgeTo(bOk)
b.AddEdgeTo(bFail)
if !commaok {
// on failure, panic by calling panicdottype
s.startBlock(bFail)
taddr := s.newValue1A(ssa.OpAddr, byteptr, &ssa.ExternSymbol{Typ: byteptr, Sym: typenamesym(n.Left.Type)}, s.sb)
s.rtcall(panicdottype, false, nil, typ, target, taddr)
// on success, return idata field
s.startBlock(bOk)
return s.newValue1(ssa.OpIData, n.Type, iface), nil
}
// commaok is the more complicated case because we have
// a control flow merge point.
bEnd := s.f.NewBlock(ssa.BlockPlain)
// type assertion succeeded
s.startBlock(bOk)
s.vars[&idataVar] = s.newValue1(ssa.OpIData, n.Type, iface)
s.vars[&okVar] = s.constBool(true)
s.endBlock()
bOk.AddEdgeTo(bEnd)
// type assertion failed
s.startBlock(bFail)
s.vars[&idataVar] = s.constNil(byteptr)
s.vars[&okVar] = s.constBool(false)
s.endBlock()
bFail.AddEdgeTo(bEnd)
// merge point
s.startBlock(bEnd)
res = s.variable(&idataVar, byteptr)
resok = s.variable(&okVar, Types[TBOOL])
delete(s.vars, &idataVar)
delete(s.vars, &okVar)
return res, resok
}
// checkgoto checks that a goto from from to to does not
// jump into a block or jump over variable declarations.
// It is a copy of checkgoto in the pre-SSA backend,
// modified only for line number handling.
// TODO: document how this works and why it is designed the way it is.
func (s *state) checkgoto(from *Node, to *Node) {
if from.Sym == to.Sym {
return
}
nf := 0
for fs := from.Sym; fs != nil; fs = fs.Link {
nf++
}
nt := 0
for fs := to.Sym; fs != nil; fs = fs.Link {
nt++
}
fs := from.Sym
for ; nf > nt; nf-- {
fs = fs.Link
}
if fs != to.Sym {
// decide what to complain about.
// prefer to complain about 'into block' over declarations,
// so scan backward to find most recent block or else dcl.
var block *Sym
var dcl *Sym
ts := to.Sym
for ; nt > nf; nt-- {
if ts.Pkg == nil {
block = ts
} else {
dcl = ts
}
ts = ts.Link
}
for ts != fs {
if ts.Pkg == nil {
block = ts
} else {
dcl = ts
}
ts = ts.Link
fs = fs.Link
}
lno := from.Left.Lineno
if block != nil {
yyerrorl(lno, "goto %v jumps into block starting at %v", from.Left.Sym, linestr(block.Lastlineno))
} else {
yyerrorl(lno, "goto %v jumps over declaration of %v at %v", from.Left.Sym, dcl, linestr(dcl.Lastlineno))
}
}
}
// variable returns the value of a variable at the current location.
func (s *state) variable(name *Node, t ssa.Type) *ssa.Value {
v := s.vars[name]
if v == nil {
v = s.newValue0A(ssa.OpFwdRef, t, name)
s.fwdRefs = append(s.fwdRefs, v)
s.vars[name] = v
s.addNamedValue(name, v)
}
return v
}
func (s *state) mem() *ssa.Value {
return s.variable(&memVar, ssa.TypeMem)
}
func (s *state) linkForwardReferences(dm *sparseDefState) {
// Build SSA graph. Each variable on its first use in a basic block
// leaves a FwdRef in that block representing the incoming value
// of that variable. This function links that ref up with possible definitions,
// inserting Phi values as needed. This is essentially the algorithm
// described by Braun, Buchwald, Hack, Leißa, Mallon, and Zwinkau:
// http://pp.info.uni-karlsruhe.de/uploads/publikationen/braun13cc.pdf
// Differences:
// - We use FwdRef nodes to postpone phi building until the CFG is
// completely built. That way we can avoid the notion of "sealed"
// blocks.
// - Phi optimization is a separate pass (in ../ssa/phielim.go).
for len(s.fwdRefs) > 0 {
v := s.fwdRefs[len(s.fwdRefs)-1]
s.fwdRefs = s.fwdRefs[:len(s.fwdRefs)-1]
s.resolveFwdRef(v, dm)
}
}
// resolveFwdRef modifies v to be the variable's value at the start of its block.
// v must be a FwdRef op.
func (s *state) resolveFwdRef(v *ssa.Value, dm *sparseDefState) {
b := v.Block
name := v.Aux.(*Node)
v.Aux = nil
if b == s.f.Entry {
// Live variable at start of function.
if s.canSSA(name) {
if strings.HasPrefix(name.Sym.Name, "autotmp_") {
// It's likely that this is an uninitialized variable in the entry block.
s.Fatalf("Treating auto as if it were arg, func %s, node %v, value %v", b.Func.Name, name, v)
}
v.Op = ssa.OpArg
v.Aux = name
return
}
// Not SSAable. Load it.
addr := s.decladdrs[name]
if addr == nil {
// TODO: closure args reach here.
s.Unimplementedf("unhandled closure arg %s at entry to function %s", name, b.Func.Name)
}
if _, ok := addr.Aux.(*ssa.ArgSymbol); !ok {
s.Fatalf("variable live at start of function %s is not an argument %s", b.Func.Name, name)
}
v.Op = ssa.OpLoad
v.AddArgs(addr, s.startmem)
return
}
if len(b.Preds) == 0 {
// This block is dead; we have no predecessors and we're not the entry block.
// It doesn't matter what we use here as long as it is well-formed.
v.Op = ssa.OpUnknown
return
}
// Find variable value on each predecessor.
var argstore [4]*ssa.Value
args := argstore[:0]
for _, e := range b.Preds {
p := e.Block()
p = dm.FindBetterDefiningBlock(name, p) // try sparse improvement on p
args = append(args, s.lookupVarOutgoing(p, v.Type, name, v.Line))
}
// Decide if we need a phi or not. We need a phi if there
// are two different args (which are both not v).
var w *ssa.Value
for _, a := range args {
if a == v {
continue // self-reference
}
if a == w {
continue // already have this witness
}
if w != nil {
// two witnesses, need a phi value
v.Op = ssa.OpPhi
v.AddArgs(args...)
return
}
w = a // save witness
}
if w == nil {
s.Fatalf("no witness for reachable phi %s", v)
}
// One witness. Make v a copy of w.
v.Op = ssa.OpCopy
v.AddArg(w)
}
// lookupVarOutgoing finds the variable's value at the end of block b.
func (s *state) lookupVarOutgoing(b *ssa.Block, t ssa.Type, name *Node, line int32) *ssa.Value {
for {
if v, ok := s.defvars[b.ID][name]; ok {
return v
}
// The variable is not defined by b and we haven't looked it up yet.
// If b has exactly one predecessor, loop to look it up there.
// Otherwise, give up and insert a new FwdRef and resolve it later.
if len(b.Preds) != 1 {
break
}
b = b.Preds[0].Block()
}
// Generate a FwdRef for the variable and return that.
v := b.NewValue0A(line, ssa.OpFwdRef, t, name)
s.fwdRefs = append(s.fwdRefs, v)
s.defvars[b.ID][name] = v
s.addNamedValue(name, v)
return v
}
func (s *state) addNamedValue(n *Node, v *ssa.Value) {
if n.Class == Pxxx {
// Don't track our dummy nodes (&memVar etc.).
return
}
if strings.HasPrefix(n.Sym.Name, "autotmp_") {
// Don't track autotmp_ variables.
return
}
if n.Class == PPARAMOUT {
// Don't track named output values. This prevents return values
// from being assigned too early. See #14591 and #14762. TODO: allow this.
return
}
if n.Class == PAUTO && n.Xoffset != 0 {
s.Fatalf("AUTO var with offset %s %d", n, n.Xoffset)
}
loc := ssa.LocalSlot{N: n, Type: n.Type, Off: 0}
values, ok := s.f.NamedValues[loc]
if !ok {
s.f.Names = append(s.f.Names, loc)
}
s.f.NamedValues[loc] = append(values, v)
}
// Branch is an unresolved branch.
type Branch struct {
P *obj.Prog // branch instruction
B *ssa.Block // target
}
// SSAGenState contains state needed during Prog generation.
type SSAGenState struct {
// Branches remembers all the branch instructions we've seen
// and where they would like to go.
Branches []Branch
// bstart remembers where each block starts (indexed by block ID)
bstart []*obj.Prog
// 387 port: maps from SSE registers (REG_X?) to 387 registers (REG_F?)
SSEto387 map[int16]int16
// Some architectures require a 64-bit temporary for FP-related register shuffling. Examples include x86-387, PPC, and Sparc V8.
ScratchFpMem *Node
}
// Pc returns the current Prog.
func (s *SSAGenState) Pc() *obj.Prog {
return Pc
}
// SetLineno sets the current source line number.
func (s *SSAGenState) SetLineno(l int32) {
lineno = l
}
// genssa appends entries to ptxt for each instruction in f.
// gcargs and gclocals are filled in with pointer maps for the frame.
func genssa(f *ssa.Func, ptxt *obj.Prog, gcargs, gclocals *Sym) {
var s SSAGenState
e := f.Config.Frontend().(*ssaExport)
// We're about to emit a bunch of Progs.
// Since the only way to get here is to explicitly request it,
// just fail on unimplemented instead of trying to unwind our mess.
e.mustImplement = true
// Remember where each block starts.
s.bstart = make([]*obj.Prog, f.NumBlocks())
var valueProgs map[*obj.Prog]*ssa.Value
var blockProgs map[*obj.Prog]*ssa.Block
var logProgs = e.log
if logProgs {
valueProgs = make(map[*obj.Prog]*ssa.Value, f.NumValues())
blockProgs = make(map[*obj.Prog]*ssa.Block, f.NumBlocks())
f.Logf("genssa %s\n", f.Name)
blockProgs[Pc] = f.Blocks[0]
}
if Thearch.Use387 {
s.SSEto387 = map[int16]int16{}
}
if f.Config.NeedsFpScratch {
s.ScratchFpMem = temp(Types[TUINT64])
}
// Emit basic blocks
for i, b := range f.Blocks {
s.bstart[b.ID] = Pc
// Emit values in block
Thearch.SSAMarkMoves(&s, b)
for _, v := range b.Values {
x := Pc
Thearch.SSAGenValue(&s, v)
if logProgs {
for ; x != Pc; x = x.Link {
valueProgs[x] = v
}
}
}
// Emit control flow instructions for block
var next *ssa.Block
if i < len(f.Blocks)-1 && (Debug['N'] == 0 || b.Kind == ssa.BlockCall) {
// If -N, leave next==nil so every block with successors
// ends in a JMP (except call blocks - plive doesn't like
// select{send,recv} followed by a JMP call). Helps keep
// line numbers for otherwise empty blocks.
next = f.Blocks[i+1]
}
x := Pc
Thearch.SSAGenBlock(&s, b, next)
if logProgs {
for ; x != Pc; x = x.Link {
blockProgs[x] = b
}
}
}
// Resolve branches
for _, br := range s.Branches {
br.P.To.Val = s.bstart[br.B.ID]
}
if logProgs {
for p := ptxt; p != nil; p = p.Link {
var s string
if v, ok := valueProgs[p]; ok {
s = v.String()
} else if b, ok := blockProgs[p]; ok {
s = b.String()
} else {
s = " " // most value and branch strings are 2-3 characters long
}
f.Logf("%s\t%s\n", s, p)
}
if f.Config.HTML != nil {
saved := ptxt.Ctxt.LineHist.PrintFilenameOnly
ptxt.Ctxt.LineHist.PrintFilenameOnly = true
var buf bytes.Buffer
buf.WriteString("<code>")
buf.WriteString("<dl class=\"ssa-gen\">")
for p := ptxt; p != nil; p = p.Link {
buf.WriteString("<dt class=\"ssa-prog-src\">")
if v, ok := valueProgs[p]; ok {
buf.WriteString(v.HTML())
} else if b, ok := blockProgs[p]; ok {
buf.WriteString(b.HTML())
}
buf.WriteString("</dt>")
buf.WriteString("<dd class=\"ssa-prog\">")
buf.WriteString(html.EscapeString(p.String()))
buf.WriteString("</dd>")
buf.WriteString("</li>")
}
buf.WriteString("</dl>")
buf.WriteString("</code>")
f.Config.HTML.WriteColumn("genssa", buf.String())
ptxt.Ctxt.LineHist.PrintFilenameOnly = saved
}
}
// Emit static data
if f.StaticData != nil {
for _, n := range f.StaticData.([]*Node) {
if !gen_as_init(n, false) {
Fatalf("non-static data marked as static: %v\n\n", n)
}
}
}
// Allocate stack frame
allocauto(ptxt)
// Generate gc bitmaps.
liveness(Curfn, ptxt, gcargs, gclocals)
// Add frame prologue. Zero ambiguously live variables.
Thearch.Defframe(ptxt)
if Debug['f'] != 0 {
frame(0)
}
// Remove leftover instrumentation from the instruction stream.
removevardef(ptxt)
f.Config.HTML.Close()
}
// movZero generates a register indirect move with a 0 immediate and keeps track of bytes left and next offset
func movZero(as obj.As, width int64, nbytes int64, offset int64, regnum int16) (nleft int64, noff int64) {
p := Prog(as)
// TODO: use zero register on archs that support it.
p.From.Type = obj.TYPE_CONST
p.From.Offset = 0
p.To.Type = obj.TYPE_MEM
p.To.Reg = regnum
p.To.Offset = offset
offset += width
nleft = nbytes - width
return nleft, offset
}
type FloatingEQNEJump struct {
Jump obj.As
Index int
}
func oneFPJump(b *ssa.Block, jumps *FloatingEQNEJump, likely ssa.BranchPrediction, branches []Branch) []Branch {
p := Prog(jumps.Jump)
p.To.Type = obj.TYPE_BRANCH
to := jumps.Index
branches = append(branches, Branch{p, b.Succs[to].Block()})
if to == 1 {
likely = -likely
}
// liblink reorders the instruction stream as it sees fit.
// Pass along what we know so liblink can make use of it.
// TODO: Once we've fully switched to SSA,
// make liblink leave our output alone.
switch likely {
case ssa.BranchUnlikely:
p.From.Type = obj.TYPE_CONST
p.From.Offset = 0
case ssa.BranchLikely:
p.From.Type = obj.TYPE_CONST
p.From.Offset = 1
}
return branches
}
func SSAGenFPJump(s *SSAGenState, b, next *ssa.Block, jumps *[2][2]FloatingEQNEJump) {
likely := b.Likely
switch next {
case b.Succs[0].Block():
s.Branches = oneFPJump(b, &jumps[0][0], likely, s.Branches)
s.Branches = oneFPJump(b, &jumps[0][1], likely, s.Branches)
case b.Succs[1].Block():
s.Branches = oneFPJump(b, &jumps[1][0], likely, s.Branches)
s.Branches = oneFPJump(b, &jumps[1][1], likely, s.Branches)
default:
s.Branches = oneFPJump(b, &jumps[1][0], likely, s.Branches)
s.Branches = oneFPJump(b, &jumps[1][1], likely, s.Branches)
q := Prog(obj.AJMP)
q.To.Type = obj.TYPE_BRANCH
s.Branches = append(s.Branches, Branch{q, b.Succs[1].Block()})
}
}
func AuxOffset(v *ssa.Value) (offset int64) {
if v.Aux == nil {
return 0
}
switch sym := v.Aux.(type) {
case *ssa.AutoSymbol:
n := sym.Node.(*Node)
return n.Xoffset
}
return 0
}
// AddAux adds the offset in the aux fields (AuxInt and Aux) of v to a.
func AddAux(a *obj.Addr, v *ssa.Value) {
AddAux2(a, v, v.AuxInt)
}
func AddAux2(a *obj.Addr, v *ssa.Value, offset int64) {
if a.Type != obj.TYPE_MEM && a.Type != obj.TYPE_ADDR {
v.Fatalf("bad AddAux addr %v", a)
}
// add integer offset
a.Offset += offset
// If no additional symbol offset, we're done.
if v.Aux == nil {
return
}
// Add symbol's offset from its base register.
switch sym := v.Aux.(type) {
case *ssa.ExternSymbol:
a.Name = obj.NAME_EXTERN
switch s := sym.Sym.(type) {
case *Sym:
a.Sym = Linksym(s)
case *obj.LSym:
a.Sym = s
default:
v.Fatalf("ExternSymbol.Sym is %T", s)
}
case *ssa.ArgSymbol:
n := sym.Node.(*Node)
a.Name = obj.NAME_PARAM
a.Node = n
a.Sym = Linksym(n.Orig.Sym)
a.Offset += n.Xoffset // TODO: why do I have to add this here? I don't for auto variables.
case *ssa.AutoSymbol:
n := sym.Node.(*Node)
a.Name = obj.NAME_AUTO
a.Node = n
a.Sym = Linksym(n.Sym)
default:
v.Fatalf("aux in %s not implemented %#v", v, v.Aux)
}
}
// SizeAlignAuxInt returns an AuxInt encoding the size and alignment of type t.
func SizeAlignAuxInt(t *Type) int64 {
return ssa.MakeSizeAndAlign(t.Size(), t.Alignment()).Int64()
}
// extendIndex extends v to a full int width.
// panic using the given function if v does not fit in an int (only on 32-bit archs).
func (s *state) extendIndex(v *ssa.Value, panicfn *Node) *ssa.Value {
size := v.Type.Size()
if size == s.config.IntSize {
return v
}
if size > s.config.IntSize {
// truncate 64-bit indexes on 32-bit pointer archs. Test the
// high word and branch to out-of-bounds failure if it is not 0.
if Debug['B'] == 0 {
hi := s.newValue1(ssa.OpInt64Hi, Types[TUINT32], v)
cmp := s.newValue2(ssa.OpEq32, Types[TBOOL], hi, s.constInt32(Types[TUINT32], 0))
s.check(cmp, panicfn)
}
return s.newValue1(ssa.OpTrunc64to32, Types[TINT], v)
}
// Extend value to the required size
var op ssa.Op
if v.Type.IsSigned() {
switch 10*size + s.config.IntSize {
case 14:
op = ssa.OpSignExt8to32
case 18:
op = ssa.OpSignExt8to64
case 24:
op = ssa.OpSignExt16to32
case 28:
op = ssa.OpSignExt16to64
case 48:
op = ssa.OpSignExt32to64
default:
s.Fatalf("bad signed index extension %s", v.Type)
}
} else {
switch 10*size + s.config.IntSize {
case 14:
op = ssa.OpZeroExt8to32
case 18:
op = ssa.OpZeroExt8to64
case 24:
op = ssa.OpZeroExt16to32
case 28:
op = ssa.OpZeroExt16to64
case 48:
op = ssa.OpZeroExt32to64
default:
s.Fatalf("bad unsigned index extension %s", v.Type)
}
}
return s.newValue1(op, Types[TINT], v)
}
// SSAReg returns the register to which v has been allocated.
func SSAReg(v *ssa.Value) *ssa.Register {
reg := v.Block.Func.RegAlloc[v.ID]
if reg == nil {
v.Fatalf("nil register for value: %s\n%s\n", v.LongString(), v.Block.Func)
}
return reg.(*ssa.Register)
}
// SSAReg0 returns the register to which the first output of v has been allocated.
func SSAReg0(v *ssa.Value) *ssa.Register {
reg := v.Block.Func.RegAlloc[v.ID].(ssa.LocPair)[0]
if reg == nil {
v.Fatalf("nil first register for value: %s\n%s\n", v.LongString(), v.Block.Func)
}
return reg.(*ssa.Register)
}
// SSAReg1 returns the register to which the second output of v has been allocated.
func SSAReg1(v *ssa.Value) *ssa.Register {
reg := v.Block.Func.RegAlloc[v.ID].(ssa.LocPair)[1]
if reg == nil {
v.Fatalf("nil second register for value: %s\n%s\n", v.LongString(), v.Block.Func)
}
return reg.(*ssa.Register)
}
// SSARegNum returns the register number (in cmd/internal/obj numbering) to which v has been allocated.
func SSARegNum(v *ssa.Value) int16 {
return Thearch.SSARegToReg[SSAReg(v).Num]
}
// SSARegNum0 returns the register number (in cmd/internal/obj numbering) to which the first output of v has been allocated.
func SSARegNum0(v *ssa.Value) int16 {
return Thearch.SSARegToReg[SSAReg0(v).Num]
}
// SSARegNum1 returns the register number (in cmd/internal/obj numbering) to which the second output of v has been allocated.
func SSARegNum1(v *ssa.Value) int16 {
return Thearch.SSARegToReg[SSAReg1(v).Num]
}
// CheckLoweredPhi checks that regalloc and stackalloc correctly handled phi values.
// Called during ssaGenValue.
func CheckLoweredPhi(v *ssa.Value) {
if v.Op != ssa.OpPhi {
v.Fatalf("CheckLoweredPhi called with non-phi value: %v", v.LongString())
}
if v.Type.IsMemory() {
return
}
f := v.Block.Func
loc := f.RegAlloc[v.ID]
for _, a := range v.Args {
if aloc := f.RegAlloc[a.ID]; aloc != loc { // TODO: .Equal() instead?
v.Fatalf("phi arg at different location than phi: %v @ %v, but arg %v @ %v\n%s\n", v, loc, a, aloc, v.Block.Func)
}
}
}
// CheckLoweredGetClosurePtr checks that v is the first instruction in the function's entry block.
// The output of LoweredGetClosurePtr is generally hardwired to the correct register.
// That register contains the closure pointer on closure entry.
func CheckLoweredGetClosurePtr(v *ssa.Value) {
entry := v.Block.Func.Entry
if entry != v.Block || entry.Values[0] != v {
Fatalf("in %s, badly placed LoweredGetClosurePtr: %v %v", v.Block.Func.Name, v.Block, v)
}
}
// AutoVar returns a *Node and int64 representing the auto variable and offset within it
// where v should be spilled.
func AutoVar(v *ssa.Value) (*Node, int64) {
loc := v.Block.Func.RegAlloc[v.ID].(ssa.LocalSlot)
if v.Type.Size() > loc.Type.Size() {
v.Fatalf("spill/restore type %s doesn't fit in slot type %s", v.Type, loc.Type)
}
return loc.N.(*Node), loc.Off
}
// fieldIdx finds the index of the field referred to by the ODOT node n.
func fieldIdx(n *Node) int {
t := n.Left.Type
f := n.Sym
if !t.IsStruct() {
panic("ODOT's LHS is not a struct")
}
var i int
for _, t1 := range t.Fields().Slice() {
if t1.Sym != f {
i++
continue
}
if t1.Offset != n.Xoffset {
panic("field offset doesn't match")
}
return i
}
panic(fmt.Sprintf("can't find field in expr %s\n", n))
// TODO: keep the result of this function somewhere in the ODOT Node
// so we don't have to recompute it each time we need it.
}
// ssaExport exports a bunch of compiler services for the ssa backend.
type ssaExport struct {
log bool
unimplemented bool
mustImplement bool
}
func (s *ssaExport) TypeBool() ssa.Type { return Types[TBOOL] }
func (s *ssaExport) TypeInt8() ssa.Type { return Types[TINT8] }
func (s *ssaExport) TypeInt16() ssa.Type { return Types[TINT16] }
func (s *ssaExport) TypeInt32() ssa.Type { return Types[TINT32] }
func (s *ssaExport) TypeInt64() ssa.Type { return Types[TINT64] }
func (s *ssaExport) TypeUInt8() ssa.Type { return Types[TUINT8] }
func (s *ssaExport) TypeUInt16() ssa.Type { return Types[TUINT16] }
func (s *ssaExport) TypeUInt32() ssa.Type { return Types[TUINT32] }
func (s *ssaExport) TypeUInt64() ssa.Type { return Types[TUINT64] }
func (s *ssaExport) TypeFloat32() ssa.Type { return Types[TFLOAT32] }
func (s *ssaExport) TypeFloat64() ssa.Type { return Types[TFLOAT64] }
func (s *ssaExport) TypeInt() ssa.Type { return Types[TINT] }
func (s *ssaExport) TypeUintptr() ssa.Type { return Types[TUINTPTR] }
func (s *ssaExport) TypeString() ssa.Type { return Types[TSTRING] }
func (s *ssaExport) TypeBytePtr() ssa.Type { return Ptrto(Types[TUINT8]) }
// StringData returns a symbol (a *Sym wrapped in an interface) which
// is the data component of a global string constant containing s.
func (*ssaExport) StringData(s string) interface{} {
// TODO: is idealstring correct? It might not matter...
_, data := stringsym(s)
return &ssa.ExternSymbol{Typ: idealstring, Sym: data}
}
func (e *ssaExport) Auto(t ssa.Type) ssa.GCNode {
n := temp(t.(*Type)) // Note: adds new auto to Curfn.Func.Dcl list
e.mustImplement = true // This modifies the input to SSA, so we want to make sure we succeed from here!
return n
}
func (e *ssaExport) SplitString(name ssa.LocalSlot) (ssa.LocalSlot, ssa.LocalSlot) {
n := name.N.(*Node)
ptrType := Ptrto(Types[TUINT8])
lenType := Types[TINT]
if n.Class == PAUTO && !n.Addrtaken {
// Split this string up into two separate variables.
p := e.namedAuto(n.Sym.Name+".ptr", ptrType)
l := e.namedAuto(n.Sym.Name+".len", lenType)
return ssa.LocalSlot{N: p, Type: ptrType, Off: 0}, ssa.LocalSlot{N: l, Type: lenType, Off: 0}
}
// Return the two parts of the larger variable.
return ssa.LocalSlot{N: n, Type: ptrType, Off: name.Off}, ssa.LocalSlot{N: n, Type: lenType, Off: name.Off + int64(Widthptr)}
}
func (e *ssaExport) SplitInterface(name ssa.LocalSlot) (ssa.LocalSlot, ssa.LocalSlot) {
n := name.N.(*Node)
t := Ptrto(Types[TUINT8])
if n.Class == PAUTO && !n.Addrtaken {
// Split this interface up into two separate variables.
f := ".itab"
if n.Type.IsEmptyInterface() {
f = ".type"
}
c := e.namedAuto(n.Sym.Name+f, t)
d := e.namedAuto(n.Sym.Name+".data", t)
return ssa.LocalSlot{N: c, Type: t, Off: 0}, ssa.LocalSlot{N: d, Type: t, Off: 0}
}
// Return the two parts of the larger variable.
return ssa.LocalSlot{N: n, Type: t, Off: name.Off}, ssa.LocalSlot{N: n, Type: t, Off: name.Off + int64(Widthptr)}
}
func (e *ssaExport) SplitSlice(name ssa.LocalSlot) (ssa.LocalSlot, ssa.LocalSlot, ssa.LocalSlot) {
n := name.N.(*Node)
ptrType := Ptrto(name.Type.ElemType().(*Type))
lenType := Types[TINT]
if n.Class == PAUTO && !n.Addrtaken {
// Split this slice up into three separate variables.
p := e.namedAuto(n.Sym.Name+".ptr", ptrType)
l := e.namedAuto(n.Sym.Name+".len", lenType)
c := e.namedAuto(n.Sym.Name+".cap", lenType)
return ssa.LocalSlot{N: p, Type: ptrType, Off: 0}, ssa.LocalSlot{N: l, Type: lenType, Off: 0}, ssa.LocalSlot{N: c, Type: lenType, Off: 0}
}
// Return the three parts of the larger variable.
return ssa.LocalSlot{N: n, Type: ptrType, Off: name.Off},
ssa.LocalSlot{N: n, Type: lenType, Off: name.Off + int64(Widthptr)},
ssa.LocalSlot{N: n, Type: lenType, Off: name.Off + int64(2*Widthptr)}
}
func (e *ssaExport) SplitComplex(name ssa.LocalSlot) (ssa.LocalSlot, ssa.LocalSlot) {
n := name.N.(*Node)
s := name.Type.Size() / 2
var t *Type
if s == 8 {
t = Types[TFLOAT64]
} else {
t = Types[TFLOAT32]
}
if n.Class == PAUTO && !n.Addrtaken {
// Split this complex up into two separate variables.
c := e.namedAuto(n.Sym.Name+".real", t)
d := e.namedAuto(n.Sym.Name+".imag", t)
return ssa.LocalSlot{N: c, Type: t, Off: 0}, ssa.LocalSlot{N: d, Type: t, Off: 0}
}
// Return the two parts of the larger variable.
return ssa.LocalSlot{N: n, Type: t, Off: name.Off}, ssa.LocalSlot{N: n, Type: t, Off: name.Off + s}
}
func (e *ssaExport) SplitInt64(name ssa.LocalSlot) (ssa.LocalSlot, ssa.LocalSlot) {
n := name.N.(*Node)
var t *Type
if name.Type.IsSigned() {
t = Types[TINT32]
} else {
t = Types[TUINT32]
}
if n.Class == PAUTO && !n.Addrtaken {
// Split this int64 up into two separate variables.
h := e.namedAuto(n.Sym.Name+".hi", t)
l := e.namedAuto(n.Sym.Name+".lo", Types[TUINT32])
return ssa.LocalSlot{N: h, Type: t, Off: 0}, ssa.LocalSlot{N: l, Type: Types[TUINT32], Off: 0}
}
// Return the two parts of the larger variable.
// Assuming little endian (we don't support big endian 32-bit architecture yet)
return ssa.LocalSlot{N: n, Type: t, Off: name.Off + 4}, ssa.LocalSlot{N: n, Type: Types[TUINT32], Off: name.Off}
}
func (e *ssaExport) SplitStruct(name ssa.LocalSlot, i int) ssa.LocalSlot {
n := name.N.(*Node)
st := name.Type
ft := st.FieldType(i)
if n.Class == PAUTO && !n.Addrtaken {
// Note: the _ field may appear several times. But
// have no fear, identically-named but distinct Autos are
// ok, albeit maybe confusing for a debugger.
x := e.namedAuto(n.Sym.Name+"."+st.FieldName(i), ft)
return ssa.LocalSlot{N: x, Type: ft, Off: 0}
}
return ssa.LocalSlot{N: n, Type: ft, Off: name.Off + st.FieldOff(i)}
}
// namedAuto returns a new AUTO variable with the given name and type.
func (e *ssaExport) namedAuto(name string, typ ssa.Type) ssa.GCNode {
t := typ.(*Type)
s := &Sym{Name: name, Pkg: autopkg}
n := Nod(ONAME, nil, nil)
s.Def = n
s.Def.Used = true
n.Sym = s
n.Type = t
n.Class = PAUTO
n.Addable = true
n.Ullman = 1
n.Esc = EscNever
n.Xoffset = 0
n.Name.Curfn = Curfn
Curfn.Func.Dcl = append(Curfn.Func.Dcl, n)
dowidth(t)
e.mustImplement = true
return n
}
func (e *ssaExport) CanSSA(t ssa.Type) bool {
return canSSAType(t.(*Type))
}
func (e *ssaExport) Line(line int32) string {
return linestr(line)
}
// Log logs a message from the compiler.
func (e *ssaExport) Logf(msg string, args ...interface{}) {
// If e was marked as unimplemented, anything could happen. Ignore.
if e.log && !e.unimplemented {
fmt.Printf(msg, args...)
}
}
func (e *ssaExport) Log() bool {
return e.log
}
// Fatal reports a compiler error and exits.
func (e *ssaExport) Fatalf(line int32, msg string, args ...interface{}) {
// If e was marked as unimplemented, anything could happen. Ignore.
if !e.unimplemented {
lineno = line
Fatalf(msg, args...)
}
}
// Unimplemented reports that the function cannot be compiled.
// It will be removed once SSA work is complete.
func (e *ssaExport) Unimplementedf(line int32, msg string, args ...interface{}) {
if e.mustImplement {
lineno = line
Fatalf(msg, args...)
}
const alwaysLog = false // enable to calculate top unimplemented features
if !e.unimplemented && (e.log || alwaysLog) {
// first implementation failure, print explanation
fmt.Printf("SSA unimplemented: "+msg+"\n", args...)
}
e.unimplemented = true
}
// Warnl reports a "warning", which is usually flag-triggered
// logging output for the benefit of tests.
func (e *ssaExport) Warnl(line int32, fmt_ string, args ...interface{}) {
Warnl(line, fmt_, args...)
}
func (e *ssaExport) Debug_checknil() bool {
return Debug_checknil != 0
}
func (n *Node) Typ() ssa.Type {
return n.Type
}
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