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| author | Cherry Mui <cherryyz@google.com> | 2024-11-01 12:04:49 -0400 |
|---|---|---|
| committer | Cherry Mui <cherryyz@google.com> | 2024-11-13 20:09:36 +0000 |
| commit | 4ffa2aecc119bd70f4765cbb9b911f47dbadd117 (patch) | |
| tree | 07d4063fb3ad87dd2e583e96664448c4a672e177 /src/cmd/internal/obj | |
| parent | 26e1010372216d013a0279be6b453fd680130881 (diff) | |
| download | go-4ffa2aecc119bd70f4765cbb9b911f47dbadd117.tar.xz | |
cmd/internal/obj/wasm: correct return PC for frameless wasmexport wrappers
For a wasmexport wrapper, we generate a call to the actual
exported Go function, and use the wrapper function's PC 1 as the
(fake) return address. This address is not used for returning,
which is handled by the Wasm call stack. It is used for stack
unwinding, and PC 1 makes it past the prologue and therefore has
the right SP delta. But if the function has no arguments and
results, the wrapper is frameless, with no prologue, and PC 1
doesn't exist. This causes the unwinder to fail. In this case, we
put PC 0, which also has the correct SP delta (0).
Fixes #69584.
Change-Id: Ic047a6e62100db540b5099cc5a56a1d0f16d58b9
Reviewed-on: https://go-review.googlesource.com/c/go/+/624000
Reviewed-by: David Chase <drchase@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Diffstat (limited to 'src/cmd/internal/obj')
| -rw-r--r-- | src/cmd/internal/obj/wasm/wasmobj.go | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/src/cmd/internal/obj/wasm/wasmobj.go b/src/cmd/internal/obj/wasm/wasmobj.go index 28ecd20cd0..48eee4e3ea 100644 --- a/src/cmd/internal/obj/wasm/wasmobj.go +++ b/src/cmd/internal/obj/wasm/wasmobj.go @@ -974,6 +974,10 @@ func genWasmExportWrapper(s *obj.LSym, appendp func(p *obj.Prog, as obj.As, args Sym: s, // PC_F Offset: 1, // PC_B=1, past the prologue, so we have the right SP delta } + if framesize == 0 { + // Frameless function, no prologue. + retAddr.Offset = 0 + } p = appendp(p, AI64Const, retAddr) p = appendp(p, AI64Store, constAddr(0)) // Set PC_B parameter to function entry @@ -1014,11 +1018,13 @@ func genWasmExportWrapper(s *obj.LSym, appendp func(p *obj.Prog, as obj.As, args } // Epilogue. Cannot use ARET as we don't follow Go calling convention. - // SP += framesize - p = appendp(p, AGet, regAddr(REG_SP)) - p = appendp(p, AI32Const, constAddr(framesize)) - p = appendp(p, AI32Add) - p = appendp(p, ASet, regAddr(REG_SP)) + if framesize > 0 { + // SP += framesize + p = appendp(p, AGet, regAddr(REG_SP)) + p = appendp(p, AI32Const, constAddr(framesize)) + p = appendp(p, AI32Add) + p = appendp(p, ASet, regAddr(REG_SP)) + } p = appendp(p, AReturn) } |