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runtime: use explicit NOFRAME on darwin/amd64

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This CL marks some darwin assembly functions as NOFRAME to avoid relying
on the implicit amd64 NOFRAME heuristic, where NOSPLIT functions
without stack were also marked as NOFRAME.

Change-Id: I797f3909bcf7f7aad304e4ede820c884231e54f6
Reviewed-on: https://go-review.googlesource.com/c/go/+/460235
Reviewed-by: Cherry Mui <cherryyz@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
This commit is contained in:
qmuntal 2023-01-02 15:54:44 +01:00 • committed by Quim Muntal
parent 89de906aa2
commit cea70301e2
2 changed files with 15 additions and 160 deletions
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4
src/cmd/internal/obj/x86/obj6.go
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@ -614,14 +614,14 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
var bpsize int
if ctxt.Arch.Family == sys.AMD64 &&
!p.From.Sym.NoFrame() && // (1) below
!(autoffset == 0 && p.From.Sym.NoSplit() && ctxt.Headtype != objabi.Hwindows) && // (2) below
!(autoffset == 0 && p.From.Sym.NoSplit() && ctxt.Headtype != objabi.Hwindows && ctxt.Headtype != objabi.Hdarwin) && // (2) below
!(autoffset == 0 && !hasCall) { // (3) below
// Make room to save a base pointer.
// There are 2 cases we must avoid:
// 1) If noframe is set (which we do for functions which tail call).
// 2) Scary runtime internals which would be all messed up by frame pointers.
// We detect these using a heuristic: frameless nosplit functions.
// Windows does not use this heuristic anymore.
// Windows and Darwin do not use this heuristic anymore.
// TODO: Maybe someday we label them all with NOFRAME and get rid of this heuristic.
// For performance, we also want to avoid:
// 3) Frameless leaf functions