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| author | Cherry Mui <cherryyz@google.com> | 2024-02-29 14:27:57 -0500 |
|---|---|---|
| committer | Cherry Mui <cherryyz@google.com> | 2025-07-16 07:14:59 -0700 |
| commit | c876bf9346f1afb5471947a65fb1e105caeff433 (patch) | |
| tree | 7ad880ca72091c7bab52e47d7ab518fb13c78c7e /src | |
| parent | b4309ece66ca989a38ed65404850a49ae8f92742 (diff) | |
| download | go-c876bf9346f1afb5471947a65fb1e105caeff433.tar.xz | |
cmd/internal/obj/wasm: use 64-bit instructions for indirect calls
Currently, on Wasm, an indirect call is compiled to
// function index = PC>>16, PC is already on stack
I32WrapI64
I32Const $16
ShrU
// set PC_B to 0
...
// actual call
CallIndirect
Specifically, the function index is extracted from bits 16-31 of
the "PC". When there are more than 65536 functions, this will
overflow and wrap around, causing wrong function being called.
This CL changes it to use 64-bit operations to extract the
function index from the "PC", so there are enough bits to for it.
For #64856.
Change-Id: I83c11db4b78cf66250e88ac02a82bd13730a8914
Reviewed-on: https://go-review.googlesource.com/c/go/+/567896
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Diffstat (limited to 'src')
| -rw-r--r-- | src/cmd/internal/obj/wasm/wasmobj.go | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/src/cmd/internal/obj/wasm/wasmobj.go b/src/cmd/internal/obj/wasm/wasmobj.go index 9a3520f319..e8bf927a82 100644 --- a/src/cmd/internal/obj/wasm/wasmobj.go +++ b/src/cmd/internal/obj/wasm/wasmobj.go @@ -465,9 +465,9 @@ func preprocess(ctxt *obj.Link, s *obj.LSym, newprog obj.ProgAlloc) { case obj.TYPE_NONE: // (target PC is on stack) + p = appendp(p, AI64Const, constAddr(16)) // only needs PC_F bits (16-63), PC_B bits (0-15) are zero + p = appendp(p, AI64ShrU) p = appendp(p, AI32WrapI64) - p = appendp(p, AI32Const, constAddr(16)) // only needs PC_F bits (16-31), PC_B bits (0-15) are zero - p = appendp(p, AI32ShrU) // Set PC_B parameter to function entry. // We need to push this before pushing the target PC_F, @@ -521,9 +521,9 @@ func preprocess(ctxt *obj.Link, s *obj.LSym, newprog obj.ProgAlloc) { case obj.TYPE_NONE: // (target PC is on stack) + p = appendp(p, AI64Const, constAddr(16)) // only needs PC_F bits (16-63), PC_B bits (0-15) are zero + p = appendp(p, AI64ShrU) p = appendp(p, AI32WrapI64) - p = appendp(p, AI32Const, constAddr(16)) // only needs PC_F bits (16-31), PC_B bits (0-15) are zero - p = appendp(p, AI32ShrU) // Set PC_B parameter to function entry. // We need to push this before pushing the target PC_F, |