Index: lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp =================================================================== --- lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp +++ lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp @@ -545,6 +545,11 @@ for (const auto &MI : reverse(*Header)) { if (MI.isCall()) { AfterSet.insert(&MI); + // Possibly throwing calls are usually wrapped by EH_LABEL + // instructions. We don't want to split them and the call. + if (MI.getIterator() != Header->begin() && + std::prev(MI.getIterator())->isEHLabel()) + AfterSet.insert(&*std::prev(MI.getIterator())); break; } } Index: lib/Target/WebAssembly/WebAssemblyLateEHPrepare.cpp =================================================================== --- lib/Target/WebAssembly/WebAssemblyLateEHPrepare.cpp +++ lib/Target/WebAssembly/WebAssemblyLateEHPrepare.cpp @@ -21,7 +21,7 @@ #include "llvm/MC/MCAsmInfo.h" using namespace llvm; -#define DEBUG_TYPE "wasm-exception-prepare" +#define DEBUG_TYPE "wasm-late-eh-prepare" namespace { class WebAssemblyLateEHPrepare final : public MachineFunctionPass { @@ -185,9 +185,12 @@ for (auto &MBB : MF) { if (MBB.isEHPad()) { Changed = true; + auto InsertPos = MBB.begin(); + if (InsertPos->isEHLabel()) // EH pad starts with an EH label + ++InsertPos; unsigned DstReg = MRI.createVirtualRegister(&WebAssembly::EXCEPT_REFRegClass); - BuildMI(MBB, MBB.begin(), MBB.begin()->getDebugLoc(), + BuildMI(MBB, InsertPos, MBB.begin()->getDebugLoc(), TII.get(WebAssembly::CATCH), DstReg); } } @@ -255,7 +258,11 @@ for (auto *Extract : ExtractInstrs) { MachineBasicBlock *EHPad = getMatchingEHPad(Extract); assert(EHPad && "No matching EH pad for extract_exception"); - MachineInstr *Catch = &*EHPad->begin(); + auto CatchPos = EHPad->begin(); + if (CatchPos->isEHLabel()) // EH pad starts with an EH label + ++CatchPos; + MachineInstr *Catch = &*CatchPos; + if (Catch->getNextNode() != Extract) EHPad->insert(Catch->getNextNode(), Extract->removeFromParent()); @@ -359,8 +366,10 @@ // with leaf functions, and we don't restore __stack_pointer in leaf // functions anyway. auto InsertPos = MBB.begin(); - if (MBB.begin()->getOpcode() == WebAssembly::CATCH) - InsertPos++; + if (InsertPos->isEHLabel()) // EH pad starts with an EH label + ++InsertPos; + if (InsertPos->getOpcode() == WebAssembly::CATCH) + ++InsertPos; FrameLowering->writeSPToGlobal(WebAssembly::SP32, MF, MBB, InsertPos, MBB.begin()->getDebugLoc()); } Index: test/CodeGen/WebAssembly/eh-labels.mir =================================================================== --- /dev/null +++ test/CodeGen/WebAssembly/eh-labels.mir @@ -0,0 +1,42 @@ +# RUN: llc -mtriple=wasm32-unknown-unknown -exception-model=wasm -mattr=+exception-handling -run-pass wasm-late-eh-prepare -run-pass wasm-cfg-stackify %s -o - | FileCheck %s + +--- | + target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128" + target triple = "wasm32-unknown-unknown" + + declare i32 @__gxx_wasm_personality_v0(...) + declare void @foo() + define void @eh_label_test() personality i8* bitcast (i32 (...)* @__gxx_wasm_personality_v0 to i8*) { + ret void + } +... + +--- +# CHECK-LABEL: eh_label_test +name: eh_label_test +liveins: + - { reg: '$arguments' } +body: | + bb.0: + ; CHECK: TRY + ; EH_LABEL + ; CALL_VOID @foo + ; EH_LABEL + successors: %bb.1, %bb.2 + EH_LABEL + CALL_VOID @foo, implicit-def dead $arguments, implicit $sp32, implicit $sp64 + EH_LABEL + + bb.1 (landing-pad): + ; predecessors: %bb.0 + successors: %bb.2 + ; CHECK: EH_LABEL + ; CHECK: CATCH + EH_LABEL + dead %0:i32 = EXTRACT_EXCEPTION_I32 implicit-def dead $arguments + CATCHRET %bb.2, %bb.0, implicit-def dead $arguments + + bb.2: + ; predecessors: %bb.0, %bb.1 + RETURN_VOID implicit-def dead $arguments +...