Adding support for Microsoft's thiscall calling convention. Clang side of the patch.

llvm-svn: 151122

1 files changed, 41 insertions, 0 deletions

diff --git a/clang/test/CodeGenCXX/thiscall-struct-return.cpp b/clang/test/CodeGenCXX/thiscall-struct-return.cpp
new file mode 100644
index 00000000000..c38fa4ac997
--- /dev/null
+++ b/clang/test/CodeGenCXX/thiscall-struct-return.cpp
@@ -0,0 +1,41 @@
+// For MSVC ABI compatibility, all structures returned by value using the
+// thiscall calling convention must use the hidden parameter.
+//
+// RUN: %clang_cc1 -triple i386-PC-Win32 %s -fms-compatibility -O0 -emit-llvm -o - | FileCheck %s
+
+// This structure would normally be returned via EAX
+struct S {
+  int i;
+};
+
+// This structure would normally be returned via EAX/EDX
+struct M {
+  int i;
+  int j;
+};
+
+class C {
+public:
+  C() {}
+
+  struct S __attribute__((thiscall)) Small() const {
+    struct S s = { 0 };
+    return s;
+  }
+
+  struct M __attribute__((thiscall)) Medium() const {
+    struct M m = { 0 };
+    return m;
+  }
+};
+
+// CHECK: define void @_Z4testv()
+void test( void ) {
+// CHECK: call void @_ZN1CC1Ev(%class.C* %c)
+  C c;
+
+// CHECK: call x86_thiscallcc void @_ZNK1C5SmallEv(%struct.S* sret %tmp, %class.C* %c)
+  (void)c.Small();
+// CHECK: call x86_thiscallcc void @_ZNK1C6MediumEv(%struct.M* sret %tmp1, %class.C* %c)
+  (void)c.Medium();
+}