cybercyst/go
1
0
Fork 0
mirror of https://github.com/golang/go.git synced 2025-05-05 15:43:04 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

cmd/compile: load properly constant values from itabs

Browse Source 
While looking at the SSA of following code, i noticed
that these rules do not work properly, and the types
are loaded indirectly through an itab, instead of statically.

type M interface{ M() }
type A interface{ A() }

type Impl struct{}
func (*Impl) M() {}
func (*Impl) A() {}

func main() {
        var a M = &Impl{}
        a.(A).A()
}

Change-Id: Ia275993f81a2e7302102d4ff87ac28586023d13c
GitHub-Last-Rev: 4bfc9019172929d0b0f1c8a1b7eb28cdbc9b87ef
GitHub-Pull-Request: golang/go#71784
Reviewed-on: https://go-review.googlesource.com/c/go/+/649500
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
This commit is contained in:
Mateusz Poliwczak 2025-02-16 17:24:19 +00:00 committed by Gopher Robot
parent ba3f568988
commit 43e6525986
3 changed files with 161 additions and 24 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
src/cmd/compile/internal/ssa/_gen/generic.rules
View File

@ -2756,10 +2756,14 @@
(RotateLeft(64|32|16|8) (RotateLeft(64|32|16|8) x c) d) && c.Type.Size() == 1 && d.Type.Size() == 1 => (RotateLeft(64|32|16|8) x (Add8 <c.Type> c d))
// Loading constant values from dictionaries and itabs.
(Load <t> (OffPtr [off] (Addr {s} sb) ) _) && t.IsUintptr() && isFixedSym(s, off) => (Addr {fixedSym(b.Func, s, off)} sb)
(Load <t> (OffPtr [off] (Convert (Addr {s} sb) _) ) _) && t.IsUintptr() && isFixedSym(s, off) => (Addr {fixedSym(b.Func, s, off)} sb)
(Load <t> (OffPtr [off] (ITab (IMake (Addr {s} sb) _))) _) && t.IsUintptr() && isFixedSym(s, off) => (Addr {fixedSym(b.Func, s, off)} sb)
(Load <t> (OffPtr [off] (ITab (IMake (Convert (Addr {s} sb) _) _))) _) && t.IsUintptr() && isFixedSym(s, off) => (Addr {fixedSym(b.Func, s, off)} sb)
(Load <typ.BytePtr> (OffPtr [off] (Addr {s} sb) ) _) && isFixedSym(s, off) => (Addr {fixedSym(b.Func, s, off)} sb)
(Load <typ.BytePtr> (OffPtr [off] (Convert (Addr {s} sb) _) ) _) && isFixedSym(s, off) => (Addr {fixedSym(b.Func, s, off)} sb)
(Load <typ.BytePtr> (OffPtr [off] (ITab (IMake (Addr {s} sb) _))) _) && isFixedSym(s, off) => (Addr {fixedSym(b.Func, s, off)} sb)
(Load <typ.BytePtr> (OffPtr [off] (ITab (IMake (Convert (Addr {s} sb) _) _))) _) && isFixedSym(s, off) => (Addr {fixedSym(b.Func, s, off)} sb)
(Load <typ.Uintptr> (OffPtr [off] (Addr {s} sb) ) _) && isFixedSym(s, off) => (Addr {fixedSym(b.Func, s, off)} sb)
(Load <typ.Uintptr> (OffPtr [off] (Convert (Addr {s} sb) _) ) _) && isFixedSym(s, off) => (Addr {fixedSym(b.Func, s, off)} sb)
(Load <typ.Uintptr> (OffPtr [off] (ITab (IMake (Addr {s} sb) _))) _) && isFixedSym(s, off) => (Addr {fixedSym(b.Func, s, off)} sb)
(Load <typ.Uintptr> (OffPtr [off] (ITab (IMake (Convert (Addr {s} sb) _) _))) _) && isFixedSym(s, off) => (Addr {fixedSym(b.Func, s, off)} sb)
// Loading constant values from runtime._type.hash.
(Load <t> (OffPtr [off] (Addr {sym} _) ) _) && t.IsInteger() && t.Size() == 4 && isFixed32(config, sym, off) => (Const32 [fixed32(config, sym, off)])

149
src/cmd/compile/internal/ssa/rewritegeneric.go
View File

@ -13519,6 +13519,7 @@ func rewriteValuegeneric_OpLoad(v *Value) bool {
v_0 := v.Args[0]
b := v.Block
config := b.Func.Config
typ := &b.Func.Config.Types
// match: (Load <t1> p1 (Store {t2} p2 x _))
// cond: isSamePtr(p1, p2) && t1.Compare(x.Type) == types.CMPeq && t1.Size() == t2.Size()
// result: x
@ -14103,12 +14104,11 @@ func rewriteValuegeneric_OpLoad(v *Value) bool {
v.AddArg(v0)
return true
}
// match: (Load <t> (OffPtr [off] (Addr {s} sb) ) _)
// cond: t.IsUintptr() && isFixedSym(s, off)
// match: (Load <typ.BytePtr> (OffPtr [off] (Addr {s} sb) ) _)
// cond: isFixedSym(s, off)
// result: (Addr {fixedSym(b.Func, s, off)} sb)
for {
t := v.Type
if v_0.Op != OpOffPtr {
if v.Type != typ.BytePtr || v_0.Op != OpOffPtr {
break
}
off := auxIntToInt64(v_0.AuxInt)
@ -14118,7 +14118,7 @@ func rewriteValuegeneric_OpLoad(v *Value) bool {
}
s := auxToSym(v_0_0.Aux)
sb := v_0_0.Args[0]
if !(t.IsUintptr() && isFixedSym(s, off)) {
if !(isFixedSym(s, off)) {
break
}
v.reset(OpAddr)
@ -14126,12 +14126,11 @@ func rewriteValuegeneric_OpLoad(v *Value) bool {
v.AddArg(sb)
return true
}
// match: (Load <t> (OffPtr [off] (Convert (Addr {s} sb) _) ) _)
// cond: t.IsUintptr() && isFixedSym(s, off)
// match: (Load <typ.BytePtr> (OffPtr [off] (Convert (Addr {s} sb) _) ) _)
// cond: isFixedSym(s, off)
// result: (Addr {fixedSym(b.Func, s, off)} sb)
for {
t := v.Type
if v_0.Op != OpOffPtr {
if v.Type != typ.BytePtr || v_0.Op != OpOffPtr {
break
}
off := auxIntToInt64(v_0.AuxInt)
@ -14145,7 +14144,7 @@ func rewriteValuegeneric_OpLoad(v *Value) bool {
}
s := auxToSym(v_0_0_0.Aux)
sb := v_0_0_0.Args[0]
if !(t.IsUintptr() && isFixedSym(s, off)) {
if !(isFixedSym(s, off)) {
break
}
v.reset(OpAddr)
@ -14153,12 +14152,11 @@ func rewriteValuegeneric_OpLoad(v *Value) bool {
v.AddArg(sb)
return true
}
// match: (Load <t> (OffPtr [off] (ITab (IMake (Addr {s} sb) _))) _)
// cond: t.IsUintptr() && isFixedSym(s, off)
// match: (Load <typ.BytePtr> (OffPtr [off] (ITab (IMake (Addr {s} sb) _))) _)
// cond: isFixedSym(s, off)
// result: (Addr {fixedSym(b.Func, s, off)} sb)
for {
t := v.Type
if v_0.Op != OpOffPtr {
if v.Type != typ.BytePtr || v_0.Op != OpOffPtr {
break
}
off := auxIntToInt64(v_0.AuxInt)
@ -14176,7 +14174,7 @@ func rewriteValuegeneric_OpLoad(v *Value) bool {
}
s := auxToSym(v_0_0_0_0.Aux)
sb := v_0_0_0_0.Args[0]
if !(t.IsUintptr() && isFixedSym(s, off)) {
if !(isFixedSym(s, off)) {
break
}
v.reset(OpAddr)
@ -14184,12 +14182,11 @@ func rewriteValuegeneric_OpLoad(v *Value) bool {
v.AddArg(sb)
return true
}
// match: (Load <t> (OffPtr [off] (ITab (IMake (Convert (Addr {s} sb) _) _))) _)
// cond: t.IsUintptr() && isFixedSym(s, off)
// match: (Load <typ.BytePtr> (OffPtr [off] (ITab (IMake (Convert (Addr {s} sb) _) _))) _)
// cond: isFixedSym(s, off)
// result: (Addr {fixedSym(b.Func, s, off)} sb)
for {
t := v.Type
if v_0.Op != OpOffPtr {
if v.Type != typ.BytePtr || v_0.Op != OpOffPtr {
break
}
off := auxIntToInt64(v_0.AuxInt)
@ -14211,7 +14208,119 @@ func rewriteValuegeneric_OpLoad(v *Value) bool {
}
s := auxToSym(v_0_0_0_0_0.Aux)
sb := v_0_0_0_0_0.Args[0]
if !(t.IsUintptr() && isFixedSym(s, off)) {
if !(isFixedSym(s, off)) {
break
}
v.reset(OpAddr)
v.Aux = symToAux(fixedSym(b.Func, s, off))
v.AddArg(sb)
return true
}
// match: (Load <typ.Uintptr> (OffPtr [off] (Addr {s} sb) ) _)
// cond: isFixedSym(s, off)
// result: (Addr {fixedSym(b.Func, s, off)} sb)
for {
if v.Type != typ.Uintptr || v_0.Op != OpOffPtr {
break
}
off := auxIntToInt64(v_0.AuxInt)
v_0_0 := v_0.Args[0]
if v_0_0.Op != OpAddr {
break
}
s := auxToSym(v_0_0.Aux)
sb := v_0_0.Args[0]
if !(isFixedSym(s, off)) {
break
}
v.reset(OpAddr)
v.Aux = symToAux(fixedSym(b.Func, s, off))
v.AddArg(sb)
return true
}
// match: (Load <typ.Uintptr> (OffPtr [off] (Convert (Addr {s} sb) _) ) _)
// cond: isFixedSym(s, off)
// result: (Addr {fixedSym(b.Func, s, off)} sb)
for {
if v.Type != typ.Uintptr || v_0.Op != OpOffPtr {
break
}
off := auxIntToInt64(v_0.AuxInt)
v_0_0 := v_0.Args[0]
if v_0_0.Op != OpConvert {
break
}
v_0_0_0 := v_0_0.Args[0]
if v_0_0_0.Op != OpAddr {
break
}
s := auxToSym(v_0_0_0.Aux)
sb := v_0_0_0.Args[0]
if !(isFixedSym(s, off)) {
break
}
v.reset(OpAddr)
v.Aux = symToAux(fixedSym(b.Func, s, off))
v.AddArg(sb)
return true
}
// match: (Load <typ.Uintptr> (OffPtr [off] (ITab (IMake (Addr {s} sb) _))) _)
// cond: isFixedSym(s, off)
// result: (Addr {fixedSym(b.Func, s, off)} sb)
for {
if v.Type != typ.Uintptr || v_0.Op != OpOffPtr {
break
}
off := auxIntToInt64(v_0.AuxInt)
v_0_0 := v_0.Args[0]
if v_0_0.Op != OpITab {
break
}
v_0_0_0 := v_0_0.Args[0]
if v_0_0_0.Op != OpIMake {
break
}
v_0_0_0_0 := v_0_0_0.Args[0]
if v_0_0_0_0.Op != OpAddr {
break
}
s := auxToSym(v_0_0_0_0.Aux)
sb := v_0_0_0_0.Args[0]
if !(isFixedSym(s, off)) {
break
}
v.reset(OpAddr)
v.Aux = symToAux(fixedSym(b.Func, s, off))
v.AddArg(sb)
return true
}
// match: (Load <typ.Uintptr> (OffPtr [off] (ITab (IMake (Convert (Addr {s} sb) _) _))) _)
// cond: isFixedSym(s, off)
// result: (Addr {fixedSym(b.Func, s, off)} sb)
for {
if v.Type != typ.Uintptr || v_0.Op != OpOffPtr {
break
}
off := auxIntToInt64(v_0.AuxInt)
v_0_0 := v_0.Args[0]
if v_0_0.Op != OpITab {
break
}
v_0_0_0 := v_0_0.Args[0]
if v_0_0_0.Op != OpIMake {
break
}
v_0_0_0_0 := v_0_0_0.Args[0]
if v_0_0_0_0.Op != OpConvert {
break
}
v_0_0_0_0_0 := v_0_0_0_0.Args[0]
if v_0_0_0_0_0.Op != OpAddr {
break
}
s := auxToSym(v_0_0_0_0_0.Aux)
sb := v_0_0_0_0_0.Args[0]
if !(isFixedSym(s, off)) {
break
}
v.reset(OpAddr)

24
test/codegen/load_type_from_itab.go Normal file
View File

@ -0,0 +1,24 @@
// asmcheck
// Copyright 2025 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.
// This test makes sure that we statically load a type from an itab, instead
// of doing a indirect load from thet itab.
package codegen
type M interface{ M() }
type A interface{ A() }
type Impl struct{}
func (*Impl) M() {}
func (*Impl) A() {}
func main() {
var a M = &Impl{}
// amd64:`LEAQ\ttype:.*Impl`
a.(A).A()
}