quantum created this revision.
quantum added reviewers: tlively, sbc100, kripken, aheejin.
Herald added subscribers: cfe-commits, sunfish, jgravelle-google, dschuff.
Herald added a project: clang.
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.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D66168
Files:
clang/lib/CodeGen/TargetInfo.cpp
clang/test/CodeGen/wasm-varargs.c
Index: clang/test/CodeGen/wasm-varargs.c
===================================================================
--- clang/test/CodeGen/wasm-varargs.c
+++ clang/test/CodeGen/wasm-varargs.c
@@ -87,12 +87,13 @@
// CHECK: [[VA1:%[^,=]+]] = bitcast i8** [[VA]] to i8*
// CHECK: call void @llvm.va_start(i8* [[VA1]])
// CHECK: [[ARGP_CUR:%[^,=]+]] = load i8*, i8** [[VA]], align 4
-// CHECK: [[ARGP_NEXT:%[^,=]+]] = getelementptr inbounds i8, i8*
[[ARGP_CUR]], i32 12
+// CHECK: [[ARGP_NEXT:%[^,=]+]] = getelementptr inbounds i8, i8*
[[ARGP_CUR]], i32 4
// CHECK: store i8* [[ARGP_NEXT]], i8** [[VA]], align 4
-// CHECK: [[R3:%[^,=]+]] = bitcast i8* [[ARGP_CUR]] to [[STRUCT_S]]*
-// CHECK: [[R4:%[^,=]+]] = bitcast [[STRUCT_S]]* [[AGG_RESULT]] to i8*
-// CHECK: [[R5:%[^,=]+]] = bitcast [[STRUCT_S]]* [[R3]] to i8*
-// CHECK: call void @llvm.memcpy.p0i8.p0i8.i32(i8* align 4 [[R4]], i8* align
4 [[R5]], i32 12, i1 false)
+// CHECK: [[R3:%[^,=]+]] = bitcast i8* [[ARGP_CUR]] to [[STRUCT_S]]**
+// CHECK: [[R4:%[^,=]+]] = load [[STRUCT_S]]*, [[STRUCT_S]]** %0, align 4
+// CHECK: [[R5:%[^,=]+]] = bitcast [[STRUCT_S]]* [[AGG_RESULT]] to i8*
+// CHECK: [[R6:%[^,=]+]] = bitcast [[STRUCT_S]]* [[R4]] to i8*
+// CHECK: call void @llvm.memcpy.p0i8.p0i8.i32(i8* align 4 [[R5]], i8* align
4 [[R6]], i32 12, i1 false)
// CHECK: [[VA2:%[^,=]+]] = bitcast i8** [[VA]] to i8*
// CHECK: call void @llvm.va_end(i8* [[VA2]])
// CHECK: ret void
Index: clang/lib/CodeGen/TargetInfo.cpp
===================================================================
--- clang/lib/CodeGen/TargetInfo.cpp
+++ 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);
}
//===----------------------------------------------------------------------===//
Index: clang/test/CodeGen/wasm-varargs.c
===================================================================
--- clang/test/CodeGen/wasm-varargs.c
+++ clang/test/CodeGen/wasm-varargs.c
@@ -87,12 +87,13 @@
// CHECK: [[VA1:%[^,=]+]] = bitcast i8** [[VA]] to i8*
// CHECK: call void @llvm.va_start(i8* [[VA1]])
// CHECK: [[ARGP_CUR:%[^,=]+]] = load i8*, i8** [[VA]], align 4
-// CHECK: [[ARGP_NEXT:%[^,=]+]] = getelementptr inbounds i8, i8* [[ARGP_CUR]], i32 12
+// CHECK: [[ARGP_NEXT:%[^,=]+]] = getelementptr inbounds i8, i8* [[ARGP_CUR]], i32 4
// CHECK: store i8* [[ARGP_NEXT]], i8** [[VA]], align 4
-// CHECK: [[R3:%[^,=]+]] = bitcast i8* [[ARGP_CUR]] to [[STRUCT_S]]*
-// CHECK: [[R4:%[^,=]+]] = bitcast [[STRUCT_S]]* [[AGG_RESULT]] to i8*
-// CHECK: [[R5:%[^,=]+]] = bitcast [[STRUCT_S]]* [[R3]] to i8*
-// CHECK: call void @llvm.memcpy.p0i8.p0i8.i32(i8* align 4 [[R4]], i8* align 4 [[R5]], i32 12, i1 false)
+// CHECK: [[R3:%[^,=]+]] = bitcast i8* [[ARGP_CUR]] to [[STRUCT_S]]**
+// CHECK: [[R4:%[^,=]+]] = load [[STRUCT_S]]*, [[STRUCT_S]]** %0, align 4
+// CHECK: [[R5:%[^,=]+]] = bitcast [[STRUCT_S]]* [[AGG_RESULT]] to i8*
+// CHECK: [[R6:%[^,=]+]] = bitcast [[STRUCT_S]]* [[R4]] to i8*
+// CHECK: call void @llvm.memcpy.p0i8.p0i8.i32(i8* align 4 [[R5]], i8* align 4 [[R6]], i32 12, i1 false)
// CHECK: [[VA2:%[^,=]+]] = bitcast i8** [[VA]] to i8*
// CHECK: call void @llvm.va_end(i8* [[VA2]])
// CHECK: ret void
Index: clang/lib/CodeGen/TargetInfo.cpp
===================================================================
--- clang/lib/CodeGen/TargetInfo.cpp
+++ 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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