[WebAssembly] Error when wasm EH is used with Emscripten EH/SjLj

- Error out when both Emscripten EH and wasm EH are used together, i.e.,
  both `-enable-emscripten-cxx-exceptions` and `-exception-model=wasm`
  are given together. This will not happen if you use Emscripten, but
  this can happen when you call `llc` manually with wrong set of
  arguments.
- Currently we don't yet support using wasm EH with Emscripten SjLj.
  Unlike `-enable-emscripten-cxx-exceptions` which is turned on only
  when you use `emcc -s DISABLE_EXCEPTION_CATCHING=0`,
  `-enable-emscripten-sjlj` is turned on by Emscripten by default. So we
  error out only when it is turned on and `setjmp` or `longjmp` is
  actually used.

Reviewed By: tlively

Differential Revision: https://reviews.llvm.org/D101403

diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp
index d3bbadf..2429f65 100644 (file)
--- a/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp
@@ -681,14 +681,19 @@ bool WebAssemblyLowerEmscriptenEHSjLj::runOnModule(Module &M) {
   bool LongjmpUsed = LongjmpF && !LongjmpF->use_empty();
   bool DoSjLj = EnableSjLj && (SetjmpUsed || LongjmpUsed);
 
-  if ((EnableEH || DoSjLj) &&
-      Triple(M.getTargetTriple()).getArch() == Triple::wasm64)
-    report_fatal_error("Emscripten EH/SjLj is not supported with wasm64 yet");
-
   auto *TPC = getAnalysisIfAvailable<TargetPassConfig>();
   assert(TPC && "Expected a TargetPassConfig");
   auto &TM = TPC->getTM<WebAssemblyTargetMachine>();
 
+  if ((EnableEH || DoSjLj) &&
+      Triple(M.getTargetTriple()).getArch() == Triple::wasm64)
+    report_fatal_error("Emscripten EH/SjLj is not supported with wasm64 yet");
+  if (EnableEH && TM.Options.ExceptionModel == ExceptionHandling::Wasm)
+    report_fatal_error("-exception-model=wasm not allowed with "
+                       "-enable-emscripten-cxx-exceptions");
+  if (DoSjLj && TM.Options.ExceptionModel == ExceptionHandling::Wasm)
+    report_fatal_error("Emscripten SjLj is not supported with Wasm EH yet");
+
   // Declare (or get) global variables __THREW__, __threwValue, and
   // getTempRet0/setTempRet0 function which are used in common for both
   // exception handling and setjmp/longjmp handling

diff --git a/llvm/test/CodeGen/WebAssembly/lower-em-ehsjlj-options.ll b/llvm/test/CodeGen/WebAssembly/lower-em-ehsjlj-options.ll
index 3428d5c..fa30cd7 100644 (file)
--- a/llvm/test/CodeGen/WebAssembly/lower-em-ehsjlj-options.ll
+++ b/llvm/test/CodeGen/WebAssembly/lower-em-ehsjlj-options.ll
@@ -3,6 +3,8 @@
 ; RUN: llc < %s | FileCheck %s --check-prefix=NONE
 ; RUN: not --crash llc < %s -enable-emscripten-cxx-exceptions -mtriple=wasm64-unknown-unknown 2>&1 | FileCheck %s --check-prefix=WASM64-EH
 ; RUN: not --crash llc < %s -enable-emscripten-sjlj -mtriple=wasm64-unknown-unknown 2>&1 | FileCheck %s --check-prefix=WASM64-SJLJ
+; RUN: not --crash llc < %s -enable-emscripten-cxx-exceptions -exception-model=wasm 2>&1 | FileCheck %s --check-prefix=WASM-EH-EM-EH
+; RUN: not --crash llc < %s -enable-emscripten-sjlj -exception-model=wasm 2>&1 | FileCheck %s --check-prefix=WASM-EH-EM-SJLJ
 
 target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
 target triple = "wasm32-unknown-unknown"
@@ -104,3 +106,5 @@ attributes #2 = { nounwind }
 
 ; WASM64-EH: LLVM ERROR: Emscripten EH/SjLj is not supported with wasm64 yet
 ; WASM64-SJLJ: LLVM ERROR: Emscripten EH/SjLj is not supported with wasm64 yet
+; WASM-EH-EM-EH: LLVM ERROR: -exception-model=wasm not allowed with -enable-emscripten-cxx-exceptions
+; WASM-EH-EM-SJLJ: LLVM ERROR: Emscripten SjLj is not supported with Wasm EH yet