[WebAssembly] Don't create bitcast-wrappers for varargs.

WebAssembly varargs functions use a significantly different ABI than
non-varargs functions, and the current code in
WebAssemblyFixFunctionBitcasts doesn't handle that difference. For now,
just avoid creating wrapper functions in the presence of varargs.

llvm-svn: 292645

1 files changed, 5 insertions, 0 deletions

diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp
index adf904ee026..cdbd9ea4b09 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp
@@ -148,6 +148,11 @@ bool FixFunctionBitcasts::runOnModule(Module &M) {
     if (!Ty)
       continue;
 
+    // Wasm varargs are not ABI-compatible with non-varargs. Just ignore
+    // such casts for now.
+    if (Ty->isVarArg() || F->isVarArg())
+      continue;
+
     auto Pair = Wrappers.insert(std::make_pair(std::make_pair(F, Ty), nullptr));
     if (Pair.second)
       Pair.first->second = CreateWrapper(F, Ty);