[WebAssembly] Make clang emit correct va_arg code for structs
Summary:
In the WebAssembly backend, when lowering variadic function calls, non-single
member aggregate type arguments are always passed by pointer.
However, when emitting va_arg code in clang, the arguments are instead read as
if they are passed directly. This results in the pointer being read as the
actual structure.
Fixes https://github.com/emscripten-core/emscripten/issues/9042.
Reviewers: tlively, sbc100, kripken, aheejin, dschuff
Reviewed By: dschuff
Subscribers: dschuff, jgravelle-google, sunfish, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D66168
llvm-svn: 368750
diff --git a/clang/lib/CodeGen/TargetInfo.cpp b/clang/lib/CodeGen/TargetInfo.cpp
index 884b80c..d96b540 100644
--- a/clang/lib/CodeGen/TargetInfo.cpp
+++ b/clang/lib/CodeGen/TargetInfo.cpp
@@ -833,10 +833,12 @@
Address WebAssemblyABIInfo::EmitVAArg(CodeGenFunction &CGF, Address VAListAddr,
QualType Ty) const {
- return emitVoidPtrVAArg(CGF, VAListAddr, Ty, /*IsIndirect=*/ false,
+ bool IsIndirect =
+ isAggregateTypeForABI(Ty) && !isSingleElementStruct(Ty, getContext());
+ return emitVoidPtrVAArg(CGF, VAListAddr, Ty, IsIndirect,
getContext().getTypeInfoInChars(Ty),
CharUnits::fromQuantity(4),
- /*AllowHigherAlign=*/ true);
+ /*AllowHigherAlign=*/true);
}
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