diff options
| author | Mark Ryan <markdryan@rivosinc.com> | 2024-12-11 14:03:17 +0100 |
|---|---|---|
| committer | Joel Sing <joel@sing.id.au> | 2025-03-19 07:00:36 -0700 |
| commit | 1aee4f3464b678f135912e2b2703e0f6c060b980 (patch) | |
| tree | dea4049d25e91179507ce4d7d56ade7c819f8a77 /src/cmd/internal/obj | |
| parent | 24b395119b4df7f16915b9f01a6aded647b79bbd (diff) | |
| download | go-1aee4f3464b678f135912e2b2703e0f6c060b980.tar.xz | |
cmd/internal/obj/riscv: prevent panics on bad branches
Syntactically incorrect branches, such as
BEQ X5, X6, $1
BEQ X5, X6, 31(X10)
cause the assembler to panic, which they shouldn't really do. It's
better for the user to see a normal error, as reported for other
syntax errors in riscv64 assembly. The panics also prevent us
from writing negative tests for these sorts of errors.
Here we fix the issue by ensuring we generate a normal error instead
of panicking when the user provides an invalid branch target. We
also add a couple of negative tests.
Change-Id: I1da568999a75097484b61a01d418f5d4be3e04fa
Reviewed-on: https://go-review.googlesource.com/c/go/+/637316
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Joel Sing <joel@sing.id.au>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Meng Zhuo <mengzhuo1203@gmail.com>
Diffstat (limited to 'src/cmd/internal/obj')
| -rw-r--r-- | src/cmd/internal/obj/riscv/obj.go | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/src/cmd/internal/obj/riscv/obj.go b/src/cmd/internal/obj/riscv/obj.go index de9851519a..f9ae5fe677 100644 --- a/src/cmd/internal/obj/riscv/obj.go +++ b/src/cmd/internal/obj/riscv/obj.go @@ -769,7 +769,8 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) { switch p.As { case ABEQ, ABEQZ, ABGE, ABGEU, ABGEZ, ABGT, ABGTU, ABGTZ, ABLE, ABLEU, ABLEZ, ABLT, ABLTU, ABLTZ, ABNE, ABNEZ: if p.To.Type != obj.TYPE_BRANCH { - panic("assemble: instruction with branch-like opcode lacks destination") + ctxt.Diag("%v: instruction with branch-like opcode lacks destination", p) + break } offset := p.To.Target().Pc - p.Pc if offset < -4096 || 4096 <= offset { @@ -853,7 +854,10 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) { case obj.TYPE_BRANCH: p.To.Type, p.To.Offset = obj.TYPE_CONST, p.To.Target().Pc-p.Pc case obj.TYPE_MEM: - panic("unhandled type") + if ctxt.Errors == 0 { + // An error should have already been reported for this instruction + panic("unhandled type") + } } case AJAL: |