thiscall-struct-return.cpp
989 Bytes
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
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 -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-LABEL: define void @_Z4testv()
void test( void ) {
// CHECK: call void @_ZN1CC1Ev(%class.C* [[C:%.+]])
C c;
// CHECK: call x86_thiscallcc void @_ZNK1C5SmallEv(%struct.S* sret align 4 %{{.+}}, %class.C* [[C]])
(void)c.Small();
// CHECK: call x86_thiscallcc void @_ZNK1C6MediumEv(%struct.M* sret align 4 %{{.+}}, %class.C* [[C]])
(void)c.Medium();
}