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
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
|
; RUN: llc < %s -mtriple=i686-win32 | FileCheck %s
; RUN: llc < %s -mtriple=i686-win32 -O0 | FileCheck %s
; IR simplified from the following C++ snippet compiled for i686-windows-msvc:
; struct A { A(); ~A(); int a; };
;
; struct B {
; virtual int f(int);
; virtual int g(A, int, A);
; virtual void h(A, int, A);
; virtual A i(A, int, A);
; virtual A j(int);
; };
;
; int (B::*mp_f)(int) = &B::f;
; int (B::*mp_g)(A, int, A) = &B::g;
; void (B::*mp_h)(A, int, A) = &B::h;
; A (B::*mp_i)(A, int, A) = &B::i;
; A (B::*mp_j)(int) = &B::j;
; Each member pointer creates a thunk. The ones with inalloca are required to
; tail calls by the ABI, even at O0.
%struct.B = type { i32 (...)** }
%struct.A = type { i32 }
; CHECK-LABEL: f_thunk:
; CHECK: jmpl
; CHECK-NOT: ret
define x86_thiscallcc i32 @f_thunk(%struct.B* %this, i32) {
entry:
%1 = bitcast %struct.B* %this to i32 (%struct.B*, i32)***
%vtable = load i32 (%struct.B*, i32)*** %1
%2 = load i32 (%struct.B*, i32)** %vtable
%3 = musttail call x86_thiscallcc i32 %2(%struct.B* %this, i32 %0)
ret i32 %3
}
; Inalloca thunks shouldn't require any stores to the stack.
; CHECK-LABEL: g_thunk:
; CHECK-NOT: mov %{{.*}}, {{.*(.*esp.*)}}
; CHECK: jmpl
; CHECK-NOT: ret
define x86_thiscallcc i32 @g_thunk(%struct.B* %this, <{ %struct.A, i32, %struct.A }>* inalloca) {
entry:
%1 = bitcast %struct.B* %this to i32 (%struct.B*, <{ %struct.A, i32, %struct.A }>*)***
%vtable = load i32 (%struct.B*, <{ %struct.A, i32, %struct.A }>*)*** %1
%vfn = getelementptr inbounds i32 (%struct.B*, <{ %struct.A, i32, %struct.A }>*)** %vtable, i32 1
%2 = load i32 (%struct.B*, <{ %struct.A, i32, %struct.A }>*)** %vfn
%3 = musttail call x86_thiscallcc i32 %2(%struct.B* %this, <{ %struct.A, i32, %struct.A }>* inalloca %0)
ret i32 %3
}
; CHECK-LABEL: h_thunk:
; CHECK: jmpl
; CHECK-NOT: mov %{{.*}}, {{.*(.*esp.*)}}
; CHECK-NOT: ret
define x86_thiscallcc void @h_thunk(%struct.B* %this, <{ %struct.A, i32, %struct.A }>* inalloca) {
entry:
%1 = bitcast %struct.B* %this to void (%struct.B*, <{ %struct.A, i32, %struct.A }>*)***
%vtable = load void (%struct.B*, <{ %struct.A, i32, %struct.A }>*)*** %1
%vfn = getelementptr inbounds void (%struct.B*, <{ %struct.A, i32, %struct.A }>*)** %vtable, i32 2
%2 = load void (%struct.B*, <{ %struct.A, i32, %struct.A }>*)** %vfn
musttail call x86_thiscallcc void %2(%struct.B* %this, <{ %struct.A, i32, %struct.A }>* inalloca %0)
ret void
}
; CHECK-LABEL: i_thunk:
; CHECK-NOT: mov %{{.*}}, {{.*(.*esp.*)}}
; CHECK: jmpl
; CHECK-NOT: ret
define x86_thiscallcc %struct.A* @i_thunk(%struct.B* %this, <{ %struct.A*, %struct.A, i32, %struct.A }>* inalloca) {
entry:
%1 = bitcast %struct.B* %this to %struct.A* (%struct.B*, <{ %struct.A*, %struct.A, i32, %struct.A }>*)***
%vtable = load %struct.A* (%struct.B*, <{ %struct.A*, %struct.A, i32, %struct.A }>*)*** %1
%vfn = getelementptr inbounds %struct.A* (%struct.B*, <{ %struct.A*, %struct.A, i32, %struct.A }>*)** %vtable, i32 3
%2 = load %struct.A* (%struct.B*, <{ %struct.A*, %struct.A, i32, %struct.A }>*)** %vfn
%3 = musttail call x86_thiscallcc %struct.A* %2(%struct.B* %this, <{ %struct.A*, %struct.A, i32, %struct.A }>* inalloca %0)
ret %struct.A* %3
}
; CHECK-LABEL: j_thunk:
; CHECK: jmpl
; CHECK-NOT: ret
define x86_thiscallcc void @j_thunk(%struct.A* noalias sret %agg.result, %struct.B* %this, i32) {
entry:
%1 = bitcast %struct.B* %this to void (%struct.A*, %struct.B*, i32)***
%vtable = load void (%struct.A*, %struct.B*, i32)*** %1
%vfn = getelementptr inbounds void (%struct.A*, %struct.B*, i32)** %vtable, i32 4
%2 = load void (%struct.A*, %struct.B*, i32)** %vfn
musttail call x86_thiscallcc void %2(%struct.A* sret %agg.result, %struct.B* %this, i32 %0)
ret void
}
; CHECK-LABEL: _stdcall_thunk@8:
; CHECK-NOT: mov %{{.*}}, {{.*(.*esp.*)}}
; CHECK: jmpl
; CHECK-NOT: ret
define x86_stdcallcc i32 @stdcall_thunk(<{ %struct.B*, %struct.A }>* inalloca) {
entry:
%this_ptr = getelementptr inbounds <{ %struct.B*, %struct.A }>* %0, i32 0, i32 0
%this = load %struct.B** %this_ptr
%1 = bitcast %struct.B* %this to i32 (<{ %struct.B*, %struct.A }>*)***
%vtable = load i32 (<{ %struct.B*, %struct.A }>*)*** %1
%vfn = getelementptr inbounds i32 (<{ %struct.B*, %struct.A }>*)** %vtable, i32 1
%2 = load i32 (<{ %struct.B*, %struct.A }>*)** %vfn
%3 = musttail call x86_stdcallcc i32 %2(<{ %struct.B*, %struct.A }>* inalloca %0)
ret i32 %3
}
; CHECK-LABEL: @fastcall_thunk@8:
; CHECK-NOT: mov %{{.*}}, {{.*(.*esp.*)}}
; CHECK: jmpl
; CHECK-NOT: ret
define x86_fastcallcc i32 @fastcall_thunk(%struct.B* inreg %this, <{ %struct.A }>* inalloca) {
entry:
%1 = bitcast %struct.B* %this to i32 (%struct.B*, <{ %struct.A }>*)***
%vtable = load i32 (%struct.B*, <{ %struct.A }>*)*** %1
%vfn = getelementptr inbounds i32 (%struct.B*, <{ %struct.A }>*)** %vtable, i32 1
%2 = load i32 (%struct.B*, <{ %struct.A }>*)** %vfn
%3 = musttail call x86_fastcallcc i32 %2(%struct.B* inreg %this, <{ %struct.A }>* inalloca %0)
ret i32 %3
}
|
