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runtime: move entry method from _func to funcInfo

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This will be required when we change from storing entry PCs in _func
to entry PC offsets, which are relative to the containing module.

Notably, almost all uses of the entry method were already called
on a funcInfo. Only Func.Entry incurs the additional module
lookup cost.

This makes Entry considerably slower, but it is probably
still fast enough in absolute terms that it is OK.

name             old time/op  new time/op  delta
Func/Name-8      8.86ns ± 0%  8.33ns ± 2%    -5.92%  (p=0.000 n=12+13)
Func/Entry-8     0.64ns ± 0%  2.62ns ±36%  +310.07%  (p=0.000 n=14+15)
Func/FileLine-8  24.5ns ± 0%  25.0ns ± 4%    +2.21%  (p=0.015 n=14+13)

Change-Id: Ia2d5de5f2f83fab334f1875452b9e8e87651d340
Reviewed-on: https://go-review.googlesource.com/c/go/+/351461
Trust: Josh Bleecher Snyder <josharian@gmail.com>
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
This commit is contained in:
Josh Bleecher Snyder 2021-09-21 14:22:51 -07:00
parent 61a0a70113
commit f0c79caa13
2 changed files with 9 additions and 6 deletions
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2
src/cmd/compile/internal/test/inl_test.go
View file

@ -65,7 +65,7 @@ func TestIntendedInlining(t *testing.T) {
"(*bmap).keys",
"(*bmap).overflow",
"(*waitq).enqueue",
"(*_func).entry",
"funcInfo.entry",
// GC-related ones
"cgoInRange",

13
src/runtime/symtab.go
View file

@ -272,11 +272,14 @@ func (f *Func) raw() *_func {
}
func (f *Func) funcInfo() funcInfo {
fn := f.raw()
return f.raw().funcInfo()
}
func (f *_func) funcInfo() funcInfo {
// Find the module containing fn. fn is located in the pclntable.
// The unsafe.Pointer to uintptr conversions and arithmetic
// are safe because we are working with module addresses.
ptr := uintptr(unsafe.Pointer(fn))
ptr := uintptr(unsafe.Pointer(f))
var mod *moduledata
for datap := &firstmoduledata; datap != nil; datap = datap.next {
if len(datap.pclntable) == 0 {
@ -288,7 +291,7 @@ func (f *Func) funcInfo() funcInfo {
break
}
}
return funcInfo{fn, mod}
return funcInfo{f, mod}
}
// PCDATA and FUNCDATA table indexes.
@ -682,7 +685,7 @@ func (f *Func) Entry() uintptr {
fi := (*funcinl)(unsafe.Pointer(fn))
return fi.entry
}
return fn.entry()
return fn.funcInfo().entry()
}
// FileLine returns the file name and line number of the
@ -735,7 +738,7 @@ func (f *_func) isInlined() bool {
}
// entry returns the entry PC for f.
func (f *_func) entry() uintptr {
func (f funcInfo) entry() uintptr {
return f.entryPC
}