When compiling with -race, we insert calls to racefuncentry,
into every function. Add a rule that removes them in leaf functions,
without instrumented loads/stores.
Shaves ~30kb from "-race" version of go tool:
file difference:
go_old 15626192
go_new 15597520 [-28672 bytes]
section differences:
global text (code) = -24513 bytes (-0.358598%)
read-only data = -5849 bytes (-0.167064%)
Total difference -30362 bytes (-0.097928%)
Fixes#24662
Change-Id: Ia63bf1827f4cf2c25e3e28dcd097c150994ade0a
Reviewed-on: https://go-review.googlesource.com/121235
Run-TryBot: Ilya Tocar <ilya.tocar@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
This commit adds an explicit nil check for closure calls on wasm,
so calling a nil func causes a proper panic instead of crashing on the
WebAssembly level.
Change-Id: I6246844f316677976cdd420618be5664444c25ae
Reviewed-on: https://go-review.googlesource.com/127759
Run-TryBot: Richard Musiol <neelance@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Lack of a well-defined order between VarDef and related
address operations sometimes causes problems with store order
and write barrier transformations; glitches in the order are
made irreparable (by later optimizations) if the two parts of
the glitch straddle a split in the original block caused by
insertion of a write barrier diamond.
Fix this by creating a LocalAddr for addresses of locals
(what VarDef matters for) that takes a memory input to
help make the order explicit. Addr is modified to only
be legal for SB operand, so there is no overlap between
Addr and LocalAddr uses (there may be some downstream
cleanup from this).
Changes to generic.rules and rewrite.go ensure that codegen
tests continue to pass; CSE of LocalAddr is impaired, not
quite sure of the cost.
Fixes#26105.
Change-Id: Id4192b4440aa4e9d7ba54a465c456df9b530b515
Reviewed-on: https://go-review.googlesource.com/122483
Run-TryBot: David Chase <drchase@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
SSA can handle 1-element array, but only when the element type
is SSAable. When building SSA for INDEX of 1-element array, we
did not check the element type is SSAable. And when it's not,
it resulted in an unhandled SSA op.
Fixes#26120.
Change-Id: Id709996b5d9d90212f6c56d3f27eed320a4d8360
Reviewed-on: https://go-review.googlesource.com/121496
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
ARMv8.1 has added new instruction (LDADDAL) for atomic memory operations. This
CL improves existing atomic add intrinsics with the new instruction. Since the
new instruction is only guaranteed to be present after ARMv8.1, we guard its
usage with a conditional on CPU feature.
Performance result on ARMv8.1 machine:
name old time/op new time/op delta
Xadd-224 1.05µs ± 6% 0.02µs ± 4% -98.06% (p=0.000 n=10+8)
Xadd64-224 1.05µs ± 3% 0.02µs ±13% -98.10% (p=0.000 n=9+10)
[Geo mean] 1.05µs 0.02µs -98.08%
Performance result on ARMv8.0 machine:
name old time/op new time/op delta
Xadd-46 538ns ± 1% 541ns ± 1% +0.62% (p=0.000 n=9+9)
Xadd64-46 505ns ± 1% 508ns ± 0% +0.48% (p=0.003 n=9+8)
[Geo mean] 521ns 524ns +0.55%
Change-Id: If4b5d8d0e2d6f84fe1492a4f5de0789910ad0ee9
Reviewed-on: https://go-review.googlesource.com/81877
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Display just a few columns in ssa.html, other
columns can be expanded by clicking on collapsed column.
Use sans serif font for the text, slightly smaller font size
for non program text.
Fixes#25286
Change-Id: I1094695135401602d90b97b69e42f6dda05871a2
Reviewed-on: https://go-review.googlesource.com/117275
Run-TryBot: Yury Smolsky <yury@smolsky.by>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Go's SSA instructions only operate on registers. For example, an add
instruction would read two registers, do the addition and then write
to a register. WebAssembly's instructions, on the other hand, operate
on the stack. The add instruction first pops two values from the stack,
does the addition, then pushes the result to the stack. To fulfill
Go's semantics, one needs to map Go's single add instruction to
4 WebAssembly instructions:
- Push the value of local variable A to the stack
- Push the value of local variable B to the stack
- Do addition
- Write value from stack to local variable C
Now consider that B was set to the constant 42 before the addition:
- Push constant 42 to the stack
- Write value from stack to local variable B
This works, but is inefficient. Instead, the stack is used directly
by inlining instructions if possible. With inlining it becomes:
- Push the value of local variable A to the stack (add)
- Push constant 42 to the stack (constant)
- Do addition (add)
- Write value from stack to local variable C (add)
Note that the two SSA instructions can not be generated sequentially
anymore, because their WebAssembly instructions are interleaved.
Design doc: https://docs.google.com/document/d/131vjr4DH6JFnb-blm_uRdaC0_Nv3OUwjEY5qVCxCup4
Updates #18892
Change-Id: Ie35e1c0bebf4985fddda0d6330eb2066f9ad6dec
Reviewed-on: https://go-review.googlesource.com/103535
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
This modifies issafepoint in liveness analysis to report almost every
operation as a safe point. There are four things we don't mark as
safe-points:
1. Runtime code (other than at calls).
2. go:nosplit functions (other than at calls).
3. Instructions between the load of the write barrier-enabled flag and
the write.
4. Instructions leading up to a uintptr -> unsafe.Pointer conversion.
We'll optimize this in later CLs:
name old time/op new time/op delta
Template 185ms ± 2% 190ms ± 2% +2.95% (p=0.000 n=10+10)
Unicode 96.3ms ± 3% 96.4ms ± 1% ~ (p=0.905 n=10+9)
GoTypes 658ms ± 0% 669ms ± 1% +1.72% (p=0.000 n=10+9)
Compiler 3.14s ± 1% 3.18s ± 1% +1.56% (p=0.000 n=9+10)
SSA 7.41s ± 2% 7.59s ± 1% +2.48% (p=0.000 n=9+10)
Flate 126ms ± 1% 128ms ± 1% +2.08% (p=0.000 n=10+10)
GoParser 153ms ± 1% 157ms ± 2% +2.38% (p=0.000 n=10+10)
Reflect 437ms ± 1% 442ms ± 1% +0.98% (p=0.001 n=10+10)
Tar 178ms ± 1% 179ms ± 1% +0.67% (p=0.035 n=10+9)
XML 223ms ± 1% 229ms ± 1% +2.58% (p=0.000 n=10+10)
[Geo mean] 394ms 401ms +1.75%
No effect on binary size because we're not yet emitting these extra
safe points.
For #24543.
Change-Id: I16a1eebb9183cad7cef9d53c0fd21a973cad6859
Reviewed-on: https://go-review.googlesource.com/109348
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Currently liveness only produces a stack map index at each safe point,
so the information is summarized in a map[*ssa.Value]int. We're about
to have both a stack map index and a register map index, so replace
the int with a LivenessIndex type we can extend, and replace the map
with a LivenessMap that we can also change more easily in the future.
This also gives us an easy hook for defining the value that means "not
a safe point".
Passes toolstash -cmp.
For #24543.
Change-Id: Ic4c069839635efed4fd0f603899b80f8be3b56ec
Reviewed-on: https://go-review.googlesource.com/109347
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Currently, range loops over slices and arrays are compiled roughly
like:
for i, x := range s { b }
⇓
for i, _n, _p := 0, len(s), &s[0]; i < _n; i, _p = i+1, _p + unsafe.Sizeof(s[0]) { b }
⇓
i, _n, _p := 0, len(s), &s[0]
goto cond
body:
{ b }
i, _p = i+1, _p + unsafe.Sizeof(s[0])
cond:
if i < _n { goto body } else { goto end }
end:
The problem with this lowering is that _p may temporarily point past
the end of the allocation the moment before the loop terminates. Right
now this isn't a problem because there's never a safe-point during
this brief moment.
We're about to introduce safe-points everywhere, so this bad pointer
is going to be a problem. We could mark the increment as an unsafe
block, but this inhibits reordering opportunities and could result in
infrequent safe-points if the body is short.
Instead, this CL fixes this by changing how we compile range loops to
never produce this past-the-end pointer. It changes the lowering to
roughly:
i, _n, _p := 0, len(s), &s[0]
if i < _n { goto body } else { goto end }
top:
_p += unsafe.Sizeof(s[0])
body:
{ b }
i++
if i < _n { goto top } else { goto end }
end:
Notably, the increment is split into two parts: we increment the index
before checking the condition, but increment the pointer only *after*
the condition check has succeeded.
The implementation builds on the OFORUNTIL construct that was
introduced during the loop preemption experiments, since OFORUNTIL
places the increment and condition after the loop body. To support the
extra "late increment" step, we further define OFORUNTIL's "List"
field to contain the late increment statements. This makes all of this
a relatively small change.
This depends on the improvements to the prove pass in CL 102603. With
the current lowering, bounds-check elimination knows that i < _n in
the body because the body block is dominated by the cond block. In the
new lowering, deriving this fact requires detecting that i < _n on
*both* paths into body and hence is true in body. CL 102603 made prove
able to detect this.
The code size effect of this is minimal. The cmd/go binary on
linux/amd64 increases by 0.17%. Performance-wise, this actually
appears to be a net win, though it's mostly noise:
name old time/op new time/op delta
BinaryTree17-12 2.80s ± 0% 2.61s ± 1% -6.88% (p=0.000 n=20+18)
Fannkuch11-12 2.41s ± 0% 2.42s ± 0% +0.05% (p=0.005 n=20+20)
FmtFprintfEmpty-12 41.6ns ± 5% 41.4ns ± 6% ~ (p=0.765 n=20+19)
FmtFprintfString-12 69.4ns ± 3% 69.3ns ± 1% ~ (p=0.084 n=19+17)
FmtFprintfInt-12 76.1ns ± 1% 77.3ns ± 1% +1.57% (p=0.000 n=19+19)
FmtFprintfIntInt-12 122ns ± 2% 123ns ± 3% +0.95% (p=0.015 n=20+20)
FmtFprintfPrefixedInt-12 153ns ± 2% 151ns ± 3% -1.27% (p=0.013 n=20+20)
FmtFprintfFloat-12 215ns ± 0% 216ns ± 0% +0.47% (p=0.000 n=20+16)
FmtManyArgs-12 486ns ± 1% 498ns ± 0% +2.40% (p=0.000 n=20+17)
GobDecode-12 6.43ms ± 0% 6.50ms ± 0% +1.08% (p=0.000 n=18+19)
GobEncode-12 5.43ms ± 1% 5.47ms ± 0% +0.76% (p=0.000 n=20+20)
Gzip-12 218ms ± 1% 218ms ± 1% ~ (p=0.883 n=20+20)
Gunzip-12 38.8ms ± 0% 38.9ms ± 0% ~ (p=0.644 n=19+19)
HTTPClientServer-12 76.2µs ± 1% 76.4µs ± 2% ~ (p=0.218 n=20+20)
JSONEncode-12 12.2ms ± 0% 12.3ms ± 1% +0.45% (p=0.000 n=19+19)
JSONDecode-12 54.2ms ± 1% 53.3ms ± 0% -1.67% (p=0.000 n=20+20)
Mandelbrot200-12 3.71ms ± 0% 3.71ms ± 0% ~ (p=0.143 n=19+20)
GoParse-12 3.22ms ± 0% 3.19ms ± 1% -0.72% (p=0.000 n=20+20)
RegexpMatchEasy0_32-12 76.7ns ± 1% 75.8ns ± 1% -1.19% (p=0.000 n=20+17)
RegexpMatchEasy0_1K-12 245ns ± 1% 243ns ± 0% -0.72% (p=0.000 n=18+17)
RegexpMatchEasy1_32-12 71.9ns ± 0% 71.7ns ± 1% -0.39% (p=0.006 n=12+18)
RegexpMatchEasy1_1K-12 358ns ± 1% 354ns ± 1% -1.13% (p=0.000 n=20+19)
RegexpMatchMedium_32-12 105ns ± 2% 105ns ± 1% -0.63% (p=0.007 n=19+20)
RegexpMatchMedium_1K-12 31.9µs ± 1% 31.9µs ± 1% ~ (p=1.000 n=17+17)
RegexpMatchHard_32-12 1.51µs ± 1% 1.52µs ± 2% +0.46% (p=0.042 n=18+18)
RegexpMatchHard_1K-12 45.3µs ± 1% 45.5µs ± 2% +0.44% (p=0.029 n=18+19)
Revcomp-12 388ms ± 1% 385ms ± 0% -0.57% (p=0.000 n=19+18)
Template-12 63.0ms ± 1% 63.3ms ± 0% +0.50% (p=0.000 n=19+20)
TimeParse-12 309ns ± 1% 307ns ± 0% -0.62% (p=0.000 n=20+20)
TimeFormat-12 328ns ± 0% 333ns ± 0% +1.35% (p=0.000 n=19+19)
[Geo mean] 47.0µs 46.9µs -0.20%
(https://perf.golang.org/search?q=upload:20180326.1)
For #10958.
For #24543.
Change-Id: Icbd52e711fdbe7938a1fea3e6baca1104b53ac3a
Reviewed-on: https://go-review.googlesource.com/102604
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: David Chase <drchase@google.com>
There's a glitch in how attributes from procs that do not
generate code are combined, and the workaround for this
glitch appeared in two places.
"One big pile is better than two little ones."
Updates #25426.
Change-Id: I252f9adc5b77591720a61fa22e6f9dda33d95350
Reviewed-on: https://go-review.googlesource.com/113717
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
A new pass run after ssa building (before any other
optimization) identifies the "first" ssa node for each
statement. Other "noise" nodes are tagged as being never
appropriate for a statement boundary (e.g., VarKill, VarDef,
Phi).
Rewrite, deadcode, cse, and nilcheck are modified to move
the statement boundaries forward whenever possible if a
boundary-tagged ssa value is removed; never-boundary nodes
are ignored in this search (some operations involving
constants are also tagged as never-boundary and also ignored
because they are likely to be moved or removed during
optimization).
Code generation treats all nodes except those explicitly
marked as statement boundaries as "not statement" nodes,
and floats statement boundaries to the beginning of each
same-line run of instructions found within a basic block.
Line number html conversion was modified to make statement
boundary nodes a bit more obvious by prepending a "+".
The code in fuse.go that glued together the value slices
of two blocks produced a result that depended on the
former capacities (not lengths) of the two slices. This
causes differences in the 386 bootstrap, and also can
sometimes put values into an order that does a worse job
of preserving statement boundaries when values are removed.
Portions of two delve tests that had caught problems were
incorporated into ssa/debug_test.go. There are some
opportunities to do better with optimized code, but the
next-ing is not lying or overly jumpy.
Over 4 CLs, compilebench geomean measured binary size
increase of 3.5% and compile user time increase of 3.8%
(this is after optimization to reuse a sparse map instead
of creating multiple maps.)
This CL worsens the optimized-debugging experience with
Delve; we need to work with the delve team so that
they can use the is_stmt marks that we're emitting now.
The reference output changes from time to time depending
on other changes in the compiler, sometimes better,
sometimes worse.
This CL now includes a test ensuring that 99+% of the lines
in the Go command itself (a handy optimized binary) include
is_stmt markers.
Change-Id: I359c94e06843f1eb41f9da437bd614885aa9644a
Reviewed-on: https://go-review.googlesource.com/102435
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
This commit adds the wasm architecture to the compile command.
A later commit will contain the corresponding linker changes.
Design doc: https://docs.google.com/document/d/131vjr4DH6JFnb-blm_uRdaC0_Nv3OUwjEY5qVCxCup4
The following files are generated:
- src/cmd/compile/internal/ssa/opGen.go
- src/cmd/compile/internal/ssa/rewriteWasm.go
- src/cmd/internal/obj/wasm/anames.go
Updates #18892
Change-Id: Ifb4a96a3e427aac2362a1c97967d5667450fba3b
Reviewed-on: https://go-review.googlesource.com/103295
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
There are several things combined in this change.
First, eliminate the gobitvector type in favor
of adding a ptrbit method to bitvector.
In non-performance-critical code, use that method.
In performance critical code, though, load the bitvector data
one byte at a time and iterate only over set bits.
To support that, add and use sys.Ctz8.
name old time/op new time/op delta
StackCopyPtr-8 81.8ms ± 5% 78.9ms ± 3% -3.58% (p=0.000 n=97+96)
StackCopy-8 65.9ms ± 3% 62.8ms ± 3% -4.67% (p=0.000 n=96+92)
StackCopyNoCache-8 105ms ± 3% 102ms ± 3% -3.38% (p=0.000 n=96+95)
Change-Id: I00b80f45612708bd440b1a411a57fa6dfa24aa74
Reviewed-on: https://go-review.googlesource.com/109716
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
This change implements math.Round as an intrinsic on ppc64x so it can be
done using a single instruction.
benchmark old ns/op new ns/op delta
BenchmarkRound-16 2.60 0.69 -73.46%
Change-Id: I9408363e96201abdfc73ced7bcd5f0c29db006a8
Reviewed-on: https://go-review.googlesource.com/109395
Run-TryBot: Lynn Boger <laboger@linux.vnet.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
When we moved racewalk to buildssa, we disabled SSA of structs with
2-4 fields while instrumenting because it caused false dependencies
because for "x.f" we would emit
(StructSelect (Load (Addr x)) "f")
Even though we later simplify this to
(Load (OffPtr (Addr x) "f"))
the instrumentation saw a load of x in its entirety and would issue
appropriate race/msan calls.
The fix taken here is to directly emit the OffPtr form when x.f is
addressable and can't be represented in SSA form.
Change-Id: I0caf37bced52e9c16937466b0ac8cab6d356e525
Reviewed-on: https://go-review.googlesource.com/109360
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
The previous change sped up the pure computation form of LeadingZeros8.
This places it somewhat close to the table lookup form.
Depending on something that varies from toolchain to toolchain
(alignment, perhaps?), the slowdown from ditching the table lookup
is either 20% or 5%.
This benchmark is the best case scenario for the table lookup:
It is in the L1 cache already.
I think we're close enough that we can switch to the computational version,
and trust that the memory effects and binary size savings will be worth it.
Code:
func f8(x uint8) { z = bits.LeadingZeros8(x) }
Before:
"".f8 STEXT nosplit size=34 args=0x8 locals=0x0
0x0000 00000 (x.go:7) TEXT "".f8(SB), NOSPLIT, $0-8
0x0000 00000 (x.go:7) FUNCDATA $0, gclocals·2a5305abe05176240e61b8620e19a815(SB)
0x0000 00000 (x.go:7) FUNCDATA $1, gclocals·33cdeccccebe80329f1fdbee7f5874cb(SB)
0x0000 00000 (x.go:7) MOVBLZX "".x+8(SP), AX
0x0005 00005 (x.go:7) MOVBLZX AL, AX
0x0008 00008 (x.go:7) LEAQ math/bits.len8tab(SB), CX
0x000f 00015 (x.go:7) MOVBLZX (CX)(AX*1), AX
0x0013 00019 (x.go:7) ADDQ $-8, AX
0x0017 00023 (x.go:7) NEGQ AX
0x001a 00026 (x.go:7) MOVQ AX, "".z(SB)
0x0021 00033 (x.go:7) RET
After:
"".f8 STEXT nosplit size=30 args=0x8 locals=0x0
0x0000 00000 (x.go:7) TEXT "".f8(SB), NOSPLIT, $0-8
0x0000 00000 (x.go:7) FUNCDATA $0, gclocals·2a5305abe05176240e61b8620e19a815(SB)
0x0000 00000 (x.go:7) FUNCDATA $1, gclocals·33cdeccccebe80329f1fdbee7f5874cb(SB)
0x0000 00000 (x.go:7) MOVBLZX "".x+8(SP), AX
0x0005 00005 (x.go:7) MOVBLZX AL, AX
0x0008 00008 (x.go:7) LEAL 1(AX)(AX*1), AX
0x000c 00012 (x.go:7) BSRL AX, AX
0x000f 00015 (x.go:7) ADDQ $-8, AX
0x0013 00019 (x.go:7) NEGQ AX
0x0016 00022 (x.go:7) MOVQ AX, "".z(SB)
0x001d 00029 (x.go:7) RET
Change-Id: Icc7db50a7820fb9a3da8a816d6b6940d7f8e193e
Reviewed-on: https://go-review.googlesource.com/108942
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
This was an artifact from when we had a separate ssa.Type interface to
break circular dependency between packages ssa and gc. It's no longer
needed now that package ssa directly uses package types.
Change-Id: I6a93e5d79082815f7f0eb89507381969cc6cb403
Reviewed-on: https://go-review.googlesource.com/109137
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Currently, each architecture lowers OpConvert to an arch-specific
OpXXXconvert. This is silly because OpConvert means the same thing on
all architectures and is logically a no-op that exists only to keep
track of conversions to and from unsafe.Pointer. Furthermore, lowering
it makes it harder to recognize in other analyses, particularly
liveness analysis.
This CL eliminates the lowering of OpConvert, leaving it as the
generic op until code generation time.
The main complexity here is that we still need to register-allocate
OpConvert operations. Currently, each arch's lowered OpConvert
specifies all GP registers in its register mask. Ideally, OpConvert
wouldn't affect value homing at all, and we could just copy the home
of OpConvert's source, but this can potentially home an OpConvert in a
LocalSlot, which neither regalloc nor stackalloc expect. Rather than
try to disentangle this assumption from regalloc and stackalloc, we
continue to register-allocate OpConvert, but teach regalloc that
OpConvert can be allocated to any allocatable GP register.
For #24543.
Change-Id: I795a6aee5fd94d4444a7bafac3838a400c9f7bb6
Reviewed-on: https://go-review.googlesource.com/108496
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Focus on "isfoo" funcs that take a *Node, and conver them to isFoo
methods instead. This makes for more idiomatic Go code, and also more
readable func names.
Found candidates with grep, and applied most changes with sed. The funcs
chosen were isgoconst, isnil, and isblank. All had the same signature,
func(*Node) bool.
While at it, camelCase the isliteral and iszero function names. Don't
move these to methods, as they are only used in the backend part of gc,
which might one day be split into a separate package.
Passes toolstash -cmp on std cmd.
Change-Id: I4df081b12d36c46c253167c8841c5a841f1c5a16
Reviewed-on: https://go-review.googlesource.com/105555
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
When a neither of a conditional block's successors follows,
the block must end with a conditional branch followed by a
an unconditional branch. If the (conditional) branch is
"unlikely", invert it and swap successors to make it
likely instead.
This doesn't matter to most benchmarks on amd64, but in one
instance on amd64 it caused a 30% improvement, and it is
otherwise harmless. The problematic loop is
for i := 0; i < w; i++ {
if pw[i] != 0 {
return true
}
}
compiled under GOEXPERIMENT=preemptibleloops
This the very worst-case benchmark for that experiment.
Also in this CL is a commoning up of heavily-repeated
boilerplate, which made it much easier to see that the
changes were applied correctly. In the future this should
allow un-exporting of SSAGenState.Branches once the
boilerplate-replacement is done everywhere.
Change-Id: I0e5ded6eeb3ab1e3e0138e12d54c7e056bd99335
Reviewed-on: https://go-review.googlesource.com/104977
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Insert appropriate race/msan calls before each memory operation during
SSA construction.
This is conceptually simple, but subtle because we need to be careful
that inserted instrumentation calls don't clobber arguments that are
currently being prepared for a user function call.
reorder1 already handles introducing temporary variables for arguments
in some cases. This CL changes it to use them for all arguments when
instrumenting.
Also, we can't SSA struct types with more than one field while
instrumenting. Otherwise, concurrent uses of disjoint fields within an
SSA-able struct can introduce false races.
This is both somewhat better and somewhat worse than the old racewalk
instrumentation pass. We're now able to easily recognize cases like
constructing non-escaping closures on the stack or accessing closure
variables don't need instrumentation calls. On the other hand,
spilling escaping parameters to the heap now results in an
instrumentation call.
Overall, this CL results in a small net reduction in the number of
instrumentation calls, but a small net increase in binary size for
instrumented executables. cmd/go ends up with 5.6% fewer calls, but a
2.4% larger binary.
Fixes#19054.
Change-Id: I70d1dd32ad6340e6fdb691e6d5a01452f58e97f3
Reviewed-on: https://go-review.googlesource.com/102817
Reviewed-by: Cherry Zhang <cherryyz@google.com>
ssa's pos parameter on the Const* funcs is unused, so remove it.
ld's alloc parameter on elfnote is always true, so remove the arguments
and simplify the code.
Finally, arm's addpltreloc never has its return parameter used, so
remove it.
Change-Id: I63387ecf6ab7b5f7c20df36be823322bb98427b8
Reviewed-on: https://go-review.googlesource.com/104456
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
In gdb, "b f" gets confused if the first instruction of "f"
is not marked as a statement in the DWARF line table.
To ensure gdb is not confused, move the first statement
marker in "f" to its first instruction.
The screwy-looking conditional for "what's the first
instruction with a statement marker" will become simpler in
the future.
Fixes#24695.
Change-Id: I2eef81676b64d1bd9bff5da03b89b9dc0c18f44f
Reviewed-on: https://go-review.googlesource.com/104955
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
This commit does not change the semantics of the Call method. Its
purpose is to avoid duplication of code by making PrepareCall available
for separate use by the wasm backend.
Updates #18892
Change-Id: I04a3098f56ebf0d995791c5375dd4c03b6a202a3
Reviewed-on: https://go-review.googlesource.com/103275
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Stores to auto tmp variables can be hoisted to places
where the line numbers make debugging look "jumpy".
Turning those instructions into ones with is_stmt = 0 in
the DWARF (accomplished by marking ssa nodes with NotStmt)
makes debugging look better while still attributing the
instructions with the correct line number.
The same is true for certain register allocator spills and
reloads.
Change-Id: I97a394eb522d4911cc40b4bf5bf76d3d7221f6c0
Reviewed-on: https://go-review.googlesource.com/98415
Run-TryBot: David Chase <drchase@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
Add IsStmt information to src.lico so that suitable lines
for breakpoints (or not) can be noted, eventually for
communication to the debugger via the linker and DWARF.
The expectation is that the front end will apply statement
boundary marks because it has best information about the
input, and the optimizer will attempt to preserve these.
The exact method for placing these marks is still TBD;
ideally stopping "at" line N in unoptimized code will occur
at a point where none of the side effects of N have occurred
and all of the inputs for line N can still be observed.
The optimizer will work with the same markings supplied
for unoptimized code.
It is a goal that non-optimizing compilation should conserve
statement marks.
The optimizer will also use the not-a-statement annotation
to indicate instructions that have a line number (for
profiling purposes) but should not be the target of
debugger step, next, or breakpoints. Because instructions
marked as statements are sometimes removed, a third value
indicating that a position (instruction) can serve as a
statement if the optimizer removes the current instruction
marked as a statement for the same line. The optimizer
should attempt to conserve statement marks, but it is not
a bug if some are lost.
Includes changes to html output for GOSSAFUNC to indicate
not-default is-a-statement with bold and not-a-statement
with strikethrough.
Change-Id: Ia22c9a682f276e2ca2a4ef7a85d4b6ebf9c62b7f
Reviewed-on: https://go-review.googlesource.com/93663
Run-TryBot: David Chase <drchase@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
The ssa.Func has Type field that is described as
function signature type.
It never gets any value and remains nil.
This leads to "<T>" signature printed representation.
Given this function declaration:
func foo(x int, f func() string) (int, error)
GOSSAFUNC printed it as below:
compiling foo
foo <T>
After this change:
compiling foo
foo func(int, func() string) (int, error)
Change-Id: Iec5eec8aac5c76ff184659e30f41b2f5fe86d329
Reviewed-on: https://go-review.googlesource.com/102375
Run-TryBot: Iskander Sharipov <iskander.sharipov@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Instead of creating a new &nodfp expression for every recover() call,
or a new nodpc variable for every function instrumented by the race
detector, this CL introduces two new uintptr-typed pseudo-variables
callerSP and callerPC. These pseudo-variables act just like calls to
the runtime's getcallersp() and getcallerpc() functions.
For consistency, change runtime.gorecover's builtin stub's parameter
type from "*int32" to "uintptr".
Passes toolstash-check, but toolstash-check -race fails because of
register allocator changes.
Change-Id: I985d644653de2dac8b7b03a28829ad04dfd4f358
Reviewed-on: https://go-review.googlesource.com/99416
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
The first word of an interface is a pointer, but for the purposes
of GC we don't need to treat it as such.
1. If it is a non-empty interface, the pointer points to an itab
which is always in persistentalloc space.
2. If it is an empty interface, the pointer points to a _type.
a. If it is a compile-time-allocated type, it points into
the read-only data section.
b. If it is a reflect-allocated type, it points into the Go heap.
Reflect is responsible for keeping a reference to
the underlying type so it won't be GCd.
If we ever have a moving GC, we need to change this for 2b (as
well as scan itabs to update their itab._type fields).
Write barriers on the first word of interfaces have already been removed.
Change-Id: I643e91d7ac4de980ac2717436eff94097c65d959
Reviewed-on: https://go-review.googlesource.com/97518
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
