cmd/internal/gc: inline runtime.getg
This more closely restores what the old C runtime did.
(In C, g was an 'extern register' with the same effective
implementation as in this CL.)
On a late 2012 MacBookPro10,2, best of 5 old vs best of 5 new:
benchmark old ns/op new ns/op delta
BenchmarkBinaryTree17 4981312777 4463426605 -10.40%
BenchmarkFannkuch11 3046495712 3006819428 -1.30%
BenchmarkFmtFprintfEmpty 89.3 79.8 -10.64%
BenchmarkFmtFprintfString 284 262 -7.75%
BenchmarkFmtFprintfInt 282 262 -7.09%
BenchmarkFmtFprintfIntInt 480 448 -6.67%
BenchmarkFmtFprintfPrefixedInt 382 358 -6.28%
BenchmarkFmtFprintfFloat 529 486 -8.13%
BenchmarkFmtManyArgs 1849 1773 -4.11%
BenchmarkGobDecode 12835963 11794385 -8.11%
BenchmarkGobEncode 10527170 10288422 -2.27%
BenchmarkGzip 436109569 438422516 +0.53%
BenchmarkGunzip 110121663 109843648 -0.25%
BenchmarkHTTPClientServer 81930 85446 +4.29%
BenchmarkJSONEncode 24638574 24280603 -1.45%
BenchmarkJSONDecode 93022423 85753546 -7.81%
BenchmarkMandelbrot200 4703899 4735407 +0.67%
BenchmarkGoParse 5319853 5086843 -4.38%
BenchmarkRegexpMatchEasy0_32 151 151 +0.00%
BenchmarkRegexpMatchEasy0_1K 452 453 +0.22%
BenchmarkRegexpMatchEasy1_32 131 132 +0.76%
BenchmarkRegexpMatchEasy1_1K 761 722 -5.12%
BenchmarkRegexpMatchMedium_32 228 224 -1.75%
BenchmarkRegexpMatchMedium_1K 63751 64296 +0.85%
BenchmarkRegexpMatchHard_32 3188 3238 +1.57%
BenchmarkRegexpMatchHard_1K 95396 96756 +1.43%
BenchmarkRevcomp 661587262 687107364 +3.86%
BenchmarkTemplate 108312598 104008540 -3.97%
BenchmarkTimeParse 453 459 +1.32%
BenchmarkTimeFormat 475 441 -7.16%
The garbage benchmark from the benchmarks subrepo gets 2.6% faster as well.
Change-Id: I320aeda332db81012688b26ffab23f6581c59cfa
Reviewed-on: https://go-review.googlesource.com/8460
Reviewed-by: Rick Hudson <rlh@golang.org>
Run-TryBot: Rick Hudson <rlh@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
diff --git a/src/cmd/5g/galign.go b/src/cmd/5g/galign.go
index 1b349e1..0a6c655 100644
--- a/src/cmd/5g/galign.go
+++ b/src/cmd/5g/galign.go
@@ -64,6 +64,7 @@
gc.Thearch.Defframe = defframe
gc.Thearch.Excise = excise
gc.Thearch.Expandchecks = expandchecks
+ gc.Thearch.Getg = getg
gc.Thearch.Gins = gins
gc.Thearch.Ginscon = ginscon
gc.Thearch.Ginsnop = ginsnop
diff --git a/src/cmd/5g/ggen.go b/src/cmd/5g/ggen.go
index 753c6e0..edad7af 100644
--- a/src/cmd/5g/ggen.go
+++ b/src/cmd/5g/ggen.go
@@ -494,3 +494,10 @@
}
return false
}
+
+// res = runtime.getg()
+func getg(res *gc.Node) {
+ var n1 gc.Node
+ gc.Nodreg(&n1, res.Type, arm.REGG)
+ gmove(&n1, res)
+}
diff --git a/src/cmd/6g/galign.go b/src/cmd/6g/galign.go
index a73ddc6..74be60e 100644
--- a/src/cmd/6g/galign.go
+++ b/src/cmd/6g/galign.go
@@ -96,6 +96,7 @@
gc.Thearch.Dodiv = dodiv
gc.Thearch.Excise = excise
gc.Thearch.Expandchecks = expandchecks
+ gc.Thearch.Getg = getg
gc.Thearch.Gins = gins
gc.Thearch.Ginscon = ginscon
gc.Thearch.Ginsnop = ginsnop
diff --git a/src/cmd/6g/ggen.go b/src/cmd/6g/ggen.go
index e609d0e..ceeec25 100644
--- a/src/cmd/6g/ggen.go
+++ b/src/cmd/6g/ggen.go
@@ -671,3 +671,20 @@
}
return false
}
+
+// res = runtime.getg()
+func getg(res *gc.Node) {
+ var n1 gc.Node
+ gc.Regalloc(&n1, res.Type, res)
+ mov := optoas(gc.OAS, gc.Types[gc.Tptr])
+ p := gins(mov, nil, &n1)
+ p.From.Type = obj.TYPE_REG
+ p.From.Reg = x86.REG_TLS
+ p = gins(mov, nil, &n1)
+ p.From = p.To
+ p.From.Type = obj.TYPE_MEM
+ p.From.Index = x86.REG_TLS
+ p.From.Scale = 1
+ gmove(&n1, res)
+ gc.Regfree(&n1)
+}
diff --git a/src/cmd/7g/galign.go b/src/cmd/7g/galign.go
index 1c50c21..36b54aa 100644
--- a/src/cmd/7g/galign.go
+++ b/src/cmd/7g/galign.go
@@ -62,6 +62,7 @@
gc.Thearch.Dodiv = dodiv
gc.Thearch.Excise = excise
gc.Thearch.Expandchecks = expandchecks
+ gc.Thearch.Getg = getg
gc.Thearch.Gins = gins
gc.Thearch.Ginscon = ginscon
gc.Thearch.Ginsnop = ginsnop
diff --git a/src/cmd/7g/ggen.go b/src/cmd/7g/ggen.go
index 0fc5854..94685d7 100644
--- a/src/cmd/7g/ggen.go
+++ b/src/cmd/7g/ggen.go
@@ -532,3 +532,10 @@
p2.To.Offset = 0
}
}
+
+// res = runtime.getg()
+func getg(res *gc.Node) {
+ var n1 gc.Node
+ gc.Nodreg(&n1, res.Type, arm64.REGG)
+ gmove(&n1, res)
+}
diff --git a/src/cmd/8g/galign.go b/src/cmd/8g/galign.go
index 1c03df5..2a8e0b7 100644
--- a/src/cmd/8g/galign.go
+++ b/src/cmd/8g/galign.go
@@ -77,6 +77,7 @@
gc.Thearch.Dodiv = cgen_div
gc.Thearch.Excise = excise
gc.Thearch.Expandchecks = expandchecks
+ gc.Thearch.Getg = getg
gc.Thearch.Gins = gins
gc.Thearch.Ginscon = ginscon
gc.Thearch.Ginsnop = ginsnop
diff --git a/src/cmd/8g/ggen.go b/src/cmd/8g/ggen.go
index 115c962..9a551b0 100644
--- a/src/cmd/8g/ggen.go
+++ b/src/cmd/8g/ggen.go
@@ -944,3 +944,20 @@
}
return false
}
+
+// res = runtime.getg()
+func getg(res *gc.Node) {
+ var n1 gc.Node
+ gc.Regalloc(&n1, res.Type, res)
+ mov := optoas(gc.OAS, gc.Types[gc.Tptr])
+ p := gins(mov, nil, &n1)
+ p.From.Type = obj.TYPE_REG
+ p.From.Reg = x86.REG_TLS
+ p = gins(mov, nil, &n1)
+ p.From = p.To
+ p.From.Type = obj.TYPE_MEM
+ p.From.Index = x86.REG_TLS
+ p.From.Scale = 1
+ gmove(&n1, res)
+ gc.Regfree(&n1)
+}
diff --git a/src/cmd/9g/galign.go b/src/cmd/9g/galign.go
index b9e6c32..68eab58 100644
--- a/src/cmd/9g/galign.go
+++ b/src/cmd/9g/galign.go
@@ -71,6 +71,7 @@
gc.Thearch.Dodiv = dodiv
gc.Thearch.Excise = excise
gc.Thearch.Expandchecks = expandchecks
+ gc.Thearch.Getg = getg
gc.Thearch.Gins = gins
gc.Thearch.Ginscon = ginscon
gc.Thearch.Ginsnop = ginsnop
diff --git a/src/cmd/9g/ggen.go b/src/cmd/9g/ggen.go
index a009186..9af36a1 100644
--- a/src/cmd/9g/ggen.go
+++ b/src/cmd/9g/ggen.go
@@ -549,3 +549,10 @@
p2.To.Offset = 0
}
}
+
+// res = runtime.getg()
+func getg(res *gc.Node) {
+ var n1 gc.Node
+ gc.Nodreg(&n1, res.Type, ppc64.REGG)
+ gmove(&n1, res)
+}
diff --git a/src/cmd/internal/gc/cgen.go b/src/cmd/internal/gc/cgen.go
index 3b628ac..886a2d1 100644
--- a/src/cmd/internal/gc/cgen.go
+++ b/src/cmd/internal/gc/cgen.go
@@ -418,6 +418,10 @@
Regfree(&n1)
return
+ case OGETG:
+ Thearch.Getg(res)
+ return
+
// symmetric binary
case OAND,
OOR,
diff --git a/src/cmd/internal/gc/fmt.go b/src/cmd/internal/gc/fmt.go
index 38e358a..589f20c 100644
--- a/src/cmd/internal/gc/fmt.go
+++ b/src/cmd/internal/gc/fmt.go
@@ -976,6 +976,7 @@
OCONV: 8,
OCOPY: 8,
ODELETE: 8,
+ OGETG: 8,
OLEN: 8,
OLITERAL: 8,
OMAKESLICE: 8,
@@ -1363,7 +1364,7 @@
}
return fmt.Sprintf("%v(%v)", Oconv(int(n.Op), obj.FmtSharp), Hconv(n.List, obj.FmtComma))
- case OCALL, OCALLFUNC, OCALLINTER, OCALLMETH:
+ case OCALL, OCALLFUNC, OCALLINTER, OCALLMETH, OGETG:
var f string
f += exprfmt(n.Left, nprec)
if n.Isddd {
diff --git a/src/cmd/internal/gc/gen.go b/src/cmd/internal/gc/gen.go
index e52ff65..4b7344a 100644
--- a/src/cmd/internal/gc/gen.go
+++ b/src/cmd/internal/gc/gen.go
@@ -1002,6 +1002,10 @@
case ORETURN, ORETJMP:
cgen_ret(n)
+ // Function calls turned into compiler intrinsics.
+ // At top level, can just ignore the call and make sure to preserve side effects in the argument, if any.
+ case OGETG:
+ // nothing
case OSQRT:
cgen_discard(n.Left)
diff --git a/src/cmd/internal/gc/go.go b/src/cmd/internal/gc/go.go
index 027ad28..a6faaa5 100644
--- a/src/cmd/internal/gc/go.go
+++ b/src/cmd/internal/gc/go.go
@@ -798,6 +798,7 @@
Dodiv func(int, *Node, *Node, *Node)
Excise func(*Flow)
Expandchecks func(*obj.Prog)
+ Getg func(*Node)
Gins func(int, *Node, *Node) *obj.Prog
Ginscon func(int, int64, *Node)
Ginsnop func()
diff --git a/src/cmd/internal/gc/syntax.go b/src/cmd/internal/gc/syntax.go
index 736c7af..11cdf29 100644
--- a/src/cmd/internal/gc/syntax.go
+++ b/src/cmd/internal/gc/syntax.go
@@ -304,6 +304,7 @@
ORETJMP // return to other function
OPS // compare parity set (for x86 NaN check)
OSQRT // sqrt(float64), on systems that have hw support
+ OGETG // runtime.getg() (read g pointer)
OEND
)
diff --git a/src/cmd/internal/gc/typecheck.go b/src/cmd/internal/gc/typecheck.go
index 4399164..08262b1 100644
--- a/src/cmd/internal/gc/typecheck.go
+++ b/src/cmd/internal/gc/typecheck.go
@@ -1366,6 +1366,17 @@
t = t.Type
}
n.Type = t
+
+ if n.Op == OCALLFUNC && n.Left.Op == ONAME && (compiling_runtime != 0 || n.Left.Sym.Pkg == Runtimepkg) && n.Left.Sym.Name == "getg" {
+ // Emit code for runtime.getg() directly instead of calling function.
+ // Most such rewrites (for example the similar one for math.Sqrt) should be done in walk,
+ // so that the ordering pass can make sure to preserve the semantics of the original code
+ // (in particular, the exact time of the function call) by introducing temporaries.
+ // In this case, we know getg() always returns the same result within a given function
+ // and we want to avoid the temporaries, so we do the rewrite earlier than is typical.
+ n.Op = OGETG
+ }
+
break OpSwitch
}
@@ -1376,6 +1387,7 @@
}
n.Type = getoutargx(l.Type)
+
break OpSwitch
case OCAP, OLEN, OREAL, OIMAG:
diff --git a/src/cmd/internal/gc/walk.go b/src/cmd/internal/gc/walk.go
index bf91116..1012aa0 100644
--- a/src/cmd/internal/gc/walk.go
+++ b/src/cmd/internal/gc/walk.go
@@ -179,7 +179,8 @@
OPRINTN,
OPANIC,
OEMPTY,
- ORECOVER:
+ ORECOVER,
+ OGETG:
if n.Typecheck == 0 {
Fatal("missing typecheck: %v", Nconv(n, obj.FmtSign))
}
@@ -424,7 +425,8 @@
ONONAME,
OINDREG,
OEMPTY,
- OPARAM:
+ OPARAM,
+ OGETG:
goto ret
case ONOT,
diff --git a/src/runtime/asm_386.s b/src/runtime/asm_386.s
index bee8b29..f2222d0 100644
--- a/src/runtime/asm_386.s
+++ b/src/runtime/asm_386.s
@@ -1639,12 +1639,6 @@
// traceback from goexit1 must hit code range of goexit
BYTE $0x90 // NOP
-TEXT runtime·getg(SB),NOSPLIT,$0-4
- get_tls(CX)
- MOVL g(CX), AX
- MOVL AX, ret+0(FP)
- RET
-
TEXT runtime·prefetcht0(SB),NOSPLIT,$0-4
MOVL addr+0(FP), AX
PREFETCHT0 (AX)
diff --git a/src/runtime/asm_amd64.s b/src/runtime/asm_amd64.s
index 946e151..0e5389f 100644
--- a/src/runtime/asm_amd64.s
+++ b/src/runtime/asm_amd64.s
@@ -1673,12 +1673,6 @@
// traceback from goexit1 must hit code range of goexit
BYTE $0x90 // NOP
-TEXT runtime·getg(SB),NOSPLIT,$0-8
- get_tls(CX)
- MOVQ g(CX), AX
- MOVQ AX, ret+0(FP)
- RET
-
TEXT runtime·prefetcht0(SB),NOSPLIT,$0-8
MOVQ addr+0(FP), AX
PREFETCHT0 (AX)
diff --git a/src/runtime/asm_amd64p32.s b/src/runtime/asm_amd64p32.s
index e144c40..23e2cb9 100644
--- a/src/runtime/asm_amd64p32.s
+++ b/src/runtime/asm_amd64p32.s
@@ -1096,12 +1096,6 @@
// traceback from goexit1 must hit code range of goexit
BYTE $0x90 // NOP
-TEXT runtime·getg(SB),NOSPLIT,$0-4
- get_tls(CX)
- MOVL g(CX), AX
- MOVL AX, ret+0(FP)
- RET
-
TEXT runtime·prefetcht0(SB),NOSPLIT,$0-4
MOVL addr+0(FP), AX
PREFETCHT0 (AX)
diff --git a/src/runtime/asm_arm.s b/src/runtime/asm_arm.s
index a2e1e4b..b7042ea 100644
--- a/src/runtime/asm_arm.s
+++ b/src/runtime/asm_arm.s
@@ -984,10 +984,6 @@
// traceback from goexit1 must hit code range of goexit
MOVW R0, R0 // NOP
-TEXT runtime·getg(SB),NOSPLIT,$-4-4
- MOVW g, ret+0(FP)
- RET
-
TEXT runtime·prefetcht0(SB),NOSPLIT,$0-4
RET
diff --git a/src/runtime/asm_arm64.s b/src/runtime/asm_arm64.s
index 3c09d53..0b21a1d 100644
--- a/src/runtime/asm_arm64.s
+++ b/src/runtime/asm_arm64.s
@@ -903,10 +903,6 @@
MOVD R0, R0 // NOP
BL runtime·goexit1(SB) // does not return
-TEXT runtime·getg(SB),NOSPLIT,$-8-8
- MOVD g, ret+0(FP)
- RET
-
// TODO(aram): use PRFM here.
TEXT runtime·prefetcht0(SB),NOSPLIT,$0-8
RET
diff --git a/src/runtime/asm_ppc64x.s b/src/runtime/asm_ppc64x.s
index ef64050..5b7ad41 100644
--- a/src/runtime/asm_ppc64x.s
+++ b/src/runtime/asm_ppc64x.s
@@ -1134,10 +1134,6 @@
// traceback from goexit1 must hit code range of goexit
MOVD R0, R0 // NOP
-TEXT runtime·getg(SB),NOSPLIT,$-8-8
- MOVD g, ret+0(FP)
- RETURN
-
TEXT runtime·prefetcht0(SB),NOSPLIT,$0-8
RETURN
diff --git a/src/runtime/stubs.go b/src/runtime/stubs.go
index 99d8dd4..7b6fbb0 100644
--- a/src/runtime/stubs.go
+++ b/src/runtime/stubs.go
@@ -18,6 +18,9 @@
return unsafe.Pointer(uintptr(p) + x)
}
+// getg returns the pointer to the current g.
+// The compiler rewrites calls to this function into instructions
+// that fetch the g directly (from TLS or from the dedicated register).
func getg() *g
// mcall switches from the g to the g0 stack and invokes fn(g),
