Stowage/go
2
0
Fork 0
mirror of https://github.com/golang/go.git synced 2025-12-08 06:10:04 +00:00
Code Issues Projects Releases Packages Wiki Activity

cmd/link, runtime: use offset for _func.entry

Browse source 
The first field of the func data stored by the linker is the
entry PC for the function. Prior to this change, this was stored
as a relocation to the function. Change this to be an offset
relative to runtime.text.

This reduces the number of relocations on darwin/arm64 by about 10%.
It also slightly shrinks binaries:

file      before    after     Δ       %
addr2line 3803058   3791298   -11760  -0.309%
api       5140114   5104242   -35872  -0.698%
asm       4886850   4840626   -46224  -0.946%
buildid   2512466   2503042   -9424   -0.375%
cgo       4374770   4342274   -32496  -0.743%
compile   22920530  22769202  -151328 -0.660%
cover     4624626   4588242   -36384  -0.787%
dist      3217570   3205522   -12048  -0.374%
doc       3715026   3684498   -30528  -0.822%
fix       3148226   3119266   -28960  -0.920%
link      6350226   6313362   -36864  -0.581%
nm        3768850   3757106   -11744  -0.312%
objdump   4140594   4127618   -12976  -0.313%
pack      2227474   2218818   -8656   -0.389%
pprof     13598706  13506786  -91920  -0.676%
test2json 2497234   2487426   -9808   -0.393%
trace     10198066  10118498  -79568  -0.780%
vet       6930658   6889074   -41584  -0.600%
total     108055044 107366900 -688144 -0.637%

It should also incrementally speed up binary launching.

This is the first step towards removing enough relocations
that pages that were previously dirtied by the loader may remain clean,
which will offer memory savings useful in constrained environments.

Change-Id: Icfba55e696ba2f9c99c4f179125ba5a3ba4369c9
Reviewed-on: https://go-review.googlesource.com/c/go/+/351463
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 2021-09-28 17:06:56 -07:00
parent 88ea8a5fe0
commit d3ad216f8e
4 changed files with 76 additions and 30 deletions
Download patch file Download diff file Expand all files Collapse all files

6
src/runtime/runtime2.go
View file

@ -858,8 +858,8 @@ const (
// Keep in sync with linker (../cmd/link/internal/ld/pcln.go:/pclntab)
// and with package debug/gosym and with symtab.go in package runtime.
type _func struct {
entryPC uintptr // start pc
nameoff int32 // function name
entryoff uint32 // start pc, as offset from moduledata.text/pcHeader.textStart
nameoff int32 // function name
args int32 // in/out args size
deferreturn uint32 // offset of start of a deferreturn call instruction from entry, if any.
@ -879,7 +879,7 @@ type _func struct {
// A *Func can be either a *_func or a *funcinl, and they are distinguished
// by the first uintptr.
type funcinl struct {
ones uintptr // set to ^0 to distinguish from _func
ones uint32 // set to ^0 to distinguish from _func
entry uintptr // entry of the real (the "outermost") frame
name string
file string