Author: Derek Schuff Date: 2026-06-01T07:23:32Z New Revision: a255c1ed36a1d06f79bd2633ba9f8d900153007c
URL: https://github.com/llvm/llvm-project/commit/a255c1ed36a1d06f79bd2633ba9f8d900153007c DIFF: https://github.com/llvm/llvm-project/commit/a255c1ed36a1d06f79bd2633ba9f8d900153007c.diff LOG: [WebAssembly] Avoid crash in LateEHPrepare with empty cleanup pads (#200322) WebAssemblyLateEHPrepare::addCatchRefsAndThrowRefs was using Catch->getIterator()->getNextNode() to find the insertion position after the CATCH (or CATCH_ALL) instruction in an EH pad. If the CATCH/CATCH_ALL instruction is the last instruction in the basic block, getNextNode() returns nullptr, which causees a crash when passed to BuildMI. This patch fixes it by using std::next(Catch->getIterator()) which returns MBB.end() if the catch is the last instruction, and the overload of BuildMI that takes an iterator correctly handles BB.end(). Fixes #197077 Assisted-By: Gemini (cherry picked from commit dc40fccbc1f8fcd6d53c970efe199fc02464b986) Added: Modified: llvm/lib/Target/WebAssembly/WebAssemblyLateEHPrepare.cpp llvm/test/CodeGen/WebAssembly/exception.ll Removed: ################################################################################ diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyLateEHPrepare.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyLateEHPrepare.cpp index 8ac32f939c5f2..3189ad37d2c49 100644 --- a/llvm/lib/Target/WebAssembly/WebAssemblyLateEHPrepare.cpp +++ b/llvm/lib/Target/WebAssembly/WebAssemblyLateEHPrepare.cpp @@ -312,7 +312,8 @@ bool WebAssemblyLateEHPrepare::addCatchRefsAndThrowRefs(MachineFunction &MF) { // caught exception is rethrown. And convert RETHROWs to THROW_REFs. for (auto &[EHPad, Rethrows] : EHPadToRethrows) { auto *Catch = WebAssembly::findCatch(EHPad); - auto *InsertPos = Catch->getIterator()->getNextNode(); + assert(Catch && "CATCH not found in EHPad"); + auto InsertPos = std::next(Catch->getIterator()); auto ExnReg = MRI.createVirtualRegister(&WebAssembly::EXNREFRegClass); if (Catch->getOpcode() == WebAssembly::CATCH) { MachineInstrBuilder MIB = BuildMI(*EHPad, InsertPos, Catch->getDebugLoc(), diff --git a/llvm/test/CodeGen/WebAssembly/exception.ll b/llvm/test/CodeGen/WebAssembly/exception.ll index 11e5be83d11cd..f738216d087ec 100644 --- a/llvm/test/CodeGen/WebAssembly/exception.ll +++ b/llvm/test/CodeGen/WebAssembly/exception.ll @@ -672,5 +672,32 @@ attributes #0 = { nounwind } attributes #1 = { noreturn } attributes #2 = { noreturn nounwind } +; CHECK-LABEL: empty_cleanup_pad: +; CHECK: try_table (catch_all_ref 0) +; CHECK: throw_ref +define void @empty_cleanup_pad(i32 %arg) personality ptr @__gxx_wasm_personality_v0 { +entry: + br label %loop + +loop: + invoke void @foo() + to label %loop unwind label %cleanup + +cleanup: + %exn = cleanuppad within none [] + br label %dispatch + +dispatch: ; preds = %cleanup, %dispatch + %cond = icmp eq i32 %arg, 0 + br i1 %cond, label %ret, label %dispatch + +ret: ; preds = %dispatch + cleanupret from %exn unwind label %cleanup2 + +cleanup2: ; preds = %ret + %exn2 = cleanuppad within none [] + ret void +} + ;; The exception tag should not be defined locally ; CHECK-NOT: __cpp_exception: _______________________________________________ llvm-branch-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
