Commit 580d7838 authored by Heejin Ahn's avatar Heejin Ahn
Browse files

[WebAssembly] Fix resume-only case in Emscripten EH 

Summary:
D72308 incorrectly assumed `resume` cannot exist without a `landingpad`,
which is not true. This sets `Changed` to true whenever we make changes
to a function, including creating a call to `__resumeException` within a
function without a landing pad.

Reviewers: tlively

Subscribers: dschuff, sbc100, jgravelle-google, hiraditya, sunfish, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D73308
parent 838a28e2

llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp

+4 −1
Original line number Diff line number Diff line
@@ -751,6 +751,7 @@ bool WebAssemblyLowerEmscriptenEHSjLj::runEHOnFunction(Function &F) { 
    auto *II = dyn_cast<InvokeInst>(BB.getTerminator());

    if (!II)

      continue;

    Changed = true;

    LandingPads.insert(II->getLandingPadInst());

    IRB.SetInsertPoint(II);
@@ -791,6 +792,7 @@ bool WebAssemblyLowerEmscriptenEHSjLj::runEHOnFunction(Function &F) { 
      auto *RI = dyn_cast<ResumeInst>(&I);

      if (!RI)

        continue;

      Changed = true;



      // Split the input into legal values

      Value *Input = RI->getValue();
@@ -815,6 +817,7 @@ bool WebAssemblyLowerEmscriptenEHSjLj::runEHOnFunction(Function &F) { 
        continue;

      if (Callee->getIntrinsicID() != Intrinsic::eh_typeid_for)

        continue;

      Changed = true;



      IRB.SetInsertPoint(CI);

      CallInst *NewCI =
@@ -830,7 +833,7 @@ bool WebAssemblyLowerEmscriptenEHSjLj::runEHOnFunction(Function &F) { 
    if (auto *LPI = dyn_cast<LandingPadInst>(I))

      LandingPads.insert(LPI);

  }

  Changed = !LandingPads.empty();

  Changed |= !LandingPads.empty();



  // Handle all the landingpad for this function together, as multiple invokes

  // may share a single lp

llvm/test/CodeGen/WebAssembly/lower-em-exceptions-lpad-only.ll

deleted100644 → 0
+0 −25
Original line number Diff line number Diff line 
; RUN: opt < %s -wasm-lower-em-ehsjlj -S | FileCheck %s



target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"

target triple = "wasm32-unknown-unknown"



@_ZTIi = external constant i8*



; Checks if a module that only contains a landingpad (and resume) but not an

; invoke works correctly and does not crash.

; CHECK-LABEL: @landingpad_only

define void @landingpad_only() personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {

entry:

  br label %cont



lpad:                                             ; preds = %entry

  %0 = landingpad { i8*, i32 }

          catch i8* bitcast (i8** @_ZTIi to i8*)

          catch i8* null

  resume { i8*, i32 } %0



cont:

  ret void

}



declare i32 @__gxx_personality_v0(...)

llvm/test/CodeGen/WebAssembly/lower-em-exceptions-resume-only.ll

0 → 100644
+17 −0
Original line number Diff line number Diff line 
; RUN: opt < %s -wasm-lower-em-ehsjlj -S | FileCheck %s



target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"

target triple = "wasm32-unknown-unknown"



; Checks if a module that only contains a resume but not an invoke works

; correctly and does not crash.

; CHECK-LABEL: @resume_only

; CHECK: call void @__resumeException

define void @resume_only() personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {

entry:

  %val0 = insertvalue { i8*, i32 } undef, i8* null, 0

  %val1 = insertvalue { i8*, i32} %val0, i32 0, 1

  resume { i8*, i32 } %val1

}



declare i32 @__gxx_personality_v0(...)