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| author | Keith Randall <khr@golang.org> | 2025-05-17 15:05:56 -0700 |
|---|---|---|
| committer | Keith Randall <khr@golang.org> | 2025-10-06 14:11:41 -0700 |
| commit | 719dfcf8a8478d70360bf3c34c0e920be7b32994 (patch) | |
| tree | d58aaf3289de3bb18901e34b336da46b425f8075 /src/runtime/testdata | |
| parent | f3312124c2370c2f64a7f9ad29732ec30209647a (diff) | |
| download | go-719dfcf8a8478d70360bf3c34c0e920be7b32994.tar.xz | |
cmd/compile: redo arm64 LR/FP save and restore
Instead of storing LR (the return address) at 0(SP) and the FP
(parent's frame pointer) at -8(SP), store them at framesize-8(SP)
and framesize-16(SP), respectively.
We push and pop data onto the stack such that we're never accessing
anything below SP.
The prolog/epilog lengths are unchanged (3 insns for a typical prolog,
2 for a typical epilog).
We use 8 bytes more per frame.
Typical prologue:
STP.W (FP, LR), -16(SP)
MOVD SP, FP
SUB $C, SP
Typical epilogue:
ADD $C, SP
LDP.P 16(SP), (FP, LR)
RET
The previous word where we stored LR, at 0(SP), is now unused.
We could repurpose that slot for storing a local variable.
The new prolog and epilog instructions are recognized by libunwind,
so pc-sampling tools like perf should now be accurate. (TODO: except
maybe after the first RET instruction? Have to look into that.)
Update #73753 (fixes, for arm64)
Update #57302 (Quim thinks this will help on that issue)
Change-Id: I4800036a9a9a08aaaf35d9f99de79a36cf37ebb8
Reviewed-on: https://go-review.googlesource.com/c/go/+/674615
Reviewed-by: David Chase <drchase@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Keith Randall <khr@google.com>
Diffstat (limited to 'src/runtime/testdata')
| -rw-r--r-- | src/runtime/testdata/testprog/badtraceback.go | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/src/runtime/testdata/testprog/badtraceback.go b/src/runtime/testdata/testprog/badtraceback.go index 455118a543..36575f765d 100644 --- a/src/runtime/testdata/testprog/badtraceback.go +++ b/src/runtime/testdata/testprog/badtraceback.go @@ -41,6 +41,11 @@ func badLR2(arg int) { if runtime.GOARCH == "ppc64" || runtime.GOARCH == "ppc64le" { lrOff = 32 // FIXED_FRAME or sys.MinFrameSize } + if runtime.GOARCH == "arm64" { + // skip 8 bytes at bottom of parent frame, then point + // to the 8 bytes of the saved PC at the top of the frame. + lrOff = 16 + } lrPtr := (*uintptr)(unsafe.Pointer(uintptr(unsafe.Pointer(&arg)) - lrOff)) *lrPtr = 0xbad |