2 files changed, 53 insertions, 23 deletions

diff --git a/clang/lib/CodeGen/CGCall.cpp b/clang/lib/CodeGen/CGCall.cpp
index 5ccb8bdf2c0..44fd4d8b597 100644
--- a/clang/lib/CodeGen/CGCall.cpp
+++ b/clang/lib/CodeGen/CGCall.cpp
@@ -2859,28 +2859,33 @@ RValue CodeGenFunction::EmitCall(const CGFunctionInfo &CallInfo,
 
   if (ArgMemory) {
     llvm::Value *Arg = ArgMemory;
-    llvm::Type *LastParamTy =
-        IRFuncTy->getParamType(IRFuncTy->getNumParams() - 1);
-    if (Arg->getType() != LastParamTy) {
+    if (CallInfo.isVariadic()) {
+      // When passing non-POD arguments by value to variadic functions, we will
+      // end up with a variadic prototype and an inalloca call site.  In such
+      // cases, we can't do any parameter mismatch checks.  Give up and bitcast
+      // the callee.
+      unsigned CalleeAS =
+          cast<llvm::PointerType>(Callee->getType())->getAddressSpace();
+      Callee = Builder.CreateBitCast(
+          Callee, getTypes().GetFunctionType(CallInfo)->getPointerTo(CalleeAS));
+    } else {
+      llvm::Type *LastParamTy =
+          IRFuncTy->getParamType(IRFuncTy->getNumParams() - 1);
+      if (Arg->getType() != LastParamTy) {
 #ifndef NDEBUG
-      // Assert that these structs have equivalent element types.
-      llvm::StructType *FullTy = CallInfo.getArgStruct();
-      llvm::StructType *Prefix = cast<llvm::StructType>(
-          cast<llvm::PointerType>(LastParamTy)->getElementType());
-
-      // For variadic functions, the caller might supply a larger struct than
-      // the callee expects, and that's OK.
-      assert(Prefix->getNumElements() == FullTy->getNumElements() ||
-             (CallInfo.isVariadic() &&
-              Prefix->getNumElements() <= FullTy->getNumElements()));
-
-      for (llvm::StructType::element_iterator PI = Prefix->element_begin(),
-                                              PE = Prefix->element_end(),
-                                              FI = FullTy->element_begin();
-           PI != PE; ++PI, ++FI)
-        assert(*PI == *FI);
+        // Assert that these structs have equivalent element types.
+        llvm::StructType *FullTy = CallInfo.getArgStruct();
+        llvm::StructType *DeclaredTy = cast<llvm::StructType>(
+            cast<llvm::PointerType>(LastParamTy)->getElementType());
+        assert(DeclaredTy->getNumElements() == FullTy->getNumElements());
+        for (llvm::StructType::element_iterator DI = DeclaredTy->element_begin(),
+                                                DE = DeclaredTy->element_end(),
+                                                FI = FullTy->element_begin();
+             DI != DE; ++DI, ++FI)
+          assert(*DI == *FI);
 #endif
-      Arg = Builder.CreateBitCast(Arg, LastParamTy);
+        Arg = Builder.CreateBitCast(Arg, LastParamTy);
+      }
     }
     Args.push_back(Arg);
   }
diff --git a/clang/test/CodeGenCXX/microsoft-abi-byval-vararg.cpp b/clang/test/CodeGenCXX/microsoft-abi-byval-vararg.cpp
index 33619216e88..6a0a8601c0c 100644
--- a/clang/test/CodeGenCXX/microsoft-abi-byval-vararg.cpp
+++ b/clang/test/CodeGenCXX/microsoft-abi-byval-vararg.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -emit-llvm %s -o - -triple=i686-pc-win32 -mconstructor-aliases -fno-rtti | FileCheck %s
+// RUN: %clang_cc1 -Wno-non-pod-varargs -emit-llvm %s -o - -triple=i686-pc-win32 -mconstructor-aliases -fno-rtti | FileCheck %s
 
 #include <stdarg.h>
 
@@ -19,9 +19,34 @@ int foo(A a, ...) {
   return sum;
 }
 
+// CHECK-LABEL: define i32 @"\01?foo@@YAHUA@@ZZ"(<{ %struct.A }>* inalloca, ...)
+
 int main() {
   return foo(A(3), 1, 2, 3);
 }
 // CHECK-LABEL: define i32 @main()
-// CHECK: %[[argmem_cast:[^ ]*]] = bitcast <{ %struct.A, i32, i32, i32 }>* %argmem to <{ %struct.A }>*
-// CHECK: call i32 (<{ %struct.A }>*, ...)* @"\01?foo@@YAHUA@@ZZ"(<{ %struct.A }>* inalloca %[[argmem_cast]])
+// CHECK: %[[argmem:[^ ]*]] = alloca inalloca <{ %struct.A, i32, i32, i32 }>
+// CHECK: call i32 {{.*bitcast.*}}@"\01?foo@@YAHUA@@ZZ"{{.*}}(<{ %struct.A, i32, i32, i32 }>* inalloca %[[argmem]])
+
+void varargs_zero(...);
+void varargs_one(int, ...);
+void varargs_two(int, int, ...);
+void varargs_three(int, int, int, ...);
+void call_var_args() {
+  A x(3);
+  varargs_zero(x);
+  varargs_one(1, x);
+  varargs_two(1, 2, x);
+  varargs_three(1, 2, 3, x);
+}
+
+// CHECK-LABEL: define void @"\01?call_var_args@@YAXXZ"()
+// CHECK: call void {{.*bitcast.*varargs_zero.*}}(<{ %struct.A }>* inalloca %{{.*}})
+// CHECK: call void {{.*bitcast.*varargs_one.*}}(<{ i32, %struct.A }>* inalloca %{{.*}})
+// CHECK: call void {{.*bitcast.*varargs_two.*}}(<{ i32, i32, %struct.A }>* inalloca %{{.*}})
+// CHECK: call void {{.*bitcast.*varargs_three.*}}(<{ i32, i32, i32, %struct.A }>* inalloca %{{.*}})
+
+// CHECK-LABEL: declare void @"\01?varargs_zero@@YAXZZ"(...)
+// CHECK-LABEL: declare void @"\01?varargs_one@@YAXHZZ"(i32, ...)
+// CHECK-LABEL: declare void @"\01?varargs_two@@YAXHHZZ"(i32, i32, ...)
+// CHECK-LABEL: declare void @"\01?varargs_three@@YAXHHHZZ"(i32, i32, i32, ...)