1 ; RUN: llc -mtriple=i686-unknown-linux-gnu -O1 < %s | FileCheck %s 2 ; RUN: llc -mtriple=i686-unknown-linux-gnu -O0 < %s | FileCheck %s 3 4 ; The MSVC family of x86 calling conventions makes tail calls really tricky. 5 ; Tests of all the various combinations should live here. 6 7 declare i32 @cdecl_i32() 8 declare void @cdecl_void() 9 10 ; Don't allow tail calling these cdecl functions, because we need to clear the 11 ; incoming stack arguments for these argument-clearing conventions. 12 13 define x86_thiscallcc void @thiscall_cdecl_notail(i32 %a, i32 %b, i32 %c) { 14 tail call void @cdecl_void() 15 ret void 16 } 17 ; CHECK-LABEL: thiscall_cdecl_notail 18 ; CHECK: calll cdecl_void 19 ; CHECK: retl $8 20 21 define x86_stdcallcc void @stdcall_cdecl_notail(i32 %a, i32 %b, i32 %c) { 22 tail call void @cdecl_void() 23 ret void 24 } 25 ; CHECK-LABEL: stdcall_cdecl_notail 26 ; CHECK: calll cdecl_void 27 ; CHECK: retl $12 28 29 define x86_vectorcallcc void @vectorcall_cdecl_notail(i32 inreg %a, i32 inreg %b, i32 %c) { 30 tail call void @cdecl_void() 31 ret void 32 } 33 ; CHECK-LABEL: vectorcall_cdecl_notail 34 ; CHECK: calll cdecl_void 35 ; CHECK: retl $4 36 37 define x86_fastcallcc void @fastcall_cdecl_notail(i32 inreg %a, i32 inreg %b, i32 %c) { 38 tail call void @cdecl_void() 39 ret void 40 } 41 ; CHECK-LABEL: fastcall_cdecl_notail 42 ; CHECK: calll cdecl_void 43 ; CHECK: retl $4 44 45 46 ; Tail call to/from callee pop functions can work under the right circumstances: 47 48 declare x86_thiscallcc void @no_args_method(i8*) 49 declare x86_thiscallcc void @one_arg_method(i8*, i32) 50 declare x86_thiscallcc void @two_args_method(i8*, i32, i32) 51 declare void @ccall_func() 52 declare void @ccall_func1(i32) 53 54 define x86_thiscallcc void @thiscall_thiscall_tail(i8* %this) { 55 entry: 56 tail call x86_thiscallcc void @no_args_method(i8* %this) 57 ret void 58 } 59 ; CHECK-LABEL: thiscall_thiscall_tail: 60 ; CHECK: jmp no_args_method 61 62 define x86_thiscallcc void @thiscall_thiscall_tail2(i8* %this, i32 %a, i32 %b) { 63 entry: 64 tail call x86_thiscallcc void @two_args_method(i8* %this, i32 %a, i32 %b) 65 ret void 66 } 67 ; @two_args_method will take care of popping %a and %b from the stack for us. 68 ; CHECK-LABEL: thiscall_thiscall_tail2: 69 ; CHECK: jmp two_args_method 70 71 define x86_thiscallcc void @thiscall_thiscall_notail(i8* %this, i32 %a, i32 %b, i32 %x) { 72 entry: 73 tail call x86_thiscallcc void @two_args_method(i8* %this, i32 %a, i32 %b) 74 ret void 75 } 76 ; @two_args_method would not pop %x. 77 ; CHECK-LABEL: thiscall_thiscall_notail: 78 ; CHECK: calll two_args_method 79 ; CHECK: retl $12 80 81 define x86_thiscallcc void @thiscall_thiscall_notail2(i8* %this, i32 %a) { 82 entry: 83 tail call x86_thiscallcc void @no_args_method(i8* %this) 84 ret void 85 } 86 ; @no_args_method would not pop %x for us. Make sure this is checked even 87 ; when there are no arguments to the call. 88 ; CHECK-LABEL: thiscall_thiscall_notail2: 89 ; CHECK: calll no_args_method 90 ; CHECK: retl $4 91 92 define void @ccall_thiscall_tail(i8* %x) { 93 entry: 94 tail call x86_thiscallcc void @no_args_method(i8* %x) 95 ret void 96 } 97 ; Tail calling from ccall to thiscall works. 98 ; CHECK-LABEL: ccall_thiscall_tail: 99 ; CHECK: jmp no_args_method 100 101 define void @ccall_thiscall_notail(i8* %x, i32 %y) { 102 entry: 103 tail call x86_thiscallcc void @one_arg_method(i8* %x, i32 %y); 104 ret void 105 } 106 ; @one_arg_method would pop %y off the stack. 107 ; CHECK-LABEL: ccall_thiscall_notail: 108 ; CHECK: calll one_arg_method 109 110 define x86_thiscallcc void @thiscall_ccall_tail(i8* %this) { 111 entry: 112 tail call void @ccall_func() 113 ret void 114 } 115 ; Tail call from thiscall to ccall works if no arguments need popping. 116 ; CHECK-LABEL: thiscall_ccall_tail: 117 ; CHECK: jmp ccall_func 118 119 define x86_thiscallcc void @thiscall_ccall_notail(i8* %this, i32 %x) { 120 entry: 121 tail call void @ccall_func1(i32 %x) 122 ret void 123 } 124 ; No tail call: %x needs to be popped. 125 ; CHECK-LABEL: thiscall_ccall_notail: 126 ; CHECK: calll ccall_func1 127 ; CHECK: retl $4 128 129 %S = type { i32 (...)** } 130 define x86_thiscallcc void @tailcall_through_pointer(%S* %this, i32 %a) { 131 entry: 132 %0 = bitcast %S* %this to void (%S*, i32)*** 133 %vtable = load void (%S*, i32)**, void (%S*, i32)*** %0 134 %1 = load void (%S*, i32)*, void (%S*, i32)** %vtable 135 tail call x86_thiscallcc void %1(%S* %this, i32 %a) 136 ret void 137 } 138 ; Tail calling works through function pointers too. 139 ; CHECK-LABEL: tailcall_through_pointer: 140 ; CHECK: jmpl 141 142 define x86_stdcallcc void @stdcall_cdecl_tail() { 143 tail call void @ccall_func() 144 ret void 145 } 146 ; stdcall to cdecl works if no arguments need popping. 147 ; CHECK-LABEL: stdcall_cdecl_tail 148 ; CHECK: jmp ccall_func 149 150 define x86_vectorcallcc void @vectorcall_cdecl_tail(i32 inreg %a, i32 inreg %b) { 151 tail call void @ccall_func() 152 ret void 153 } 154 ; vectorcall to cdecl works if no arguments need popping. 155 ; CHECK-LABEL: vectorcall_cdecl_tail 156 ; CHECK: jmp ccall_func 157 158 define x86_fastcallcc void @fastcall_cdecl_tail(i32 inreg %a, i32 inreg %b) { 159 tail call void @ccall_func() 160 ret void 161 } 162 ; fastcall to cdecl works if no arguments need popping. 163 ; CHECK-LABEL: fastcall_cdecl_tail 164 ; CHECK: jmp ccall_func 165 166 define x86_stdcallcc void @stdcall_thiscall_notail(i8* %this, i32 %a, i32 %b) { 167 tail call x86_thiscallcc void @two_args_method(i8* %this, i32 %a, i32 %b) 168 ret void 169 } 170 ; two_args_method will not pop %this. 171 ; CHECK-LABEL: stdcall_thiscall_notail 172 ; CHECK: calll two_args_method 173 174 define x86_stdcallcc void @stdcall_thiscall_tail(i32 %a, i32 %b) { 175 tail call x86_thiscallcc void @two_args_method(i8* null, i32 %a, i32 %b) 176 ret void 177 } 178 ; The callee pop amounts match up. 179 ; CHECK-LABEL: stdcall_thiscall_tail 180 ; CHECK: jmp two_args_method 181 182 declare x86_fastcallcc void @fastcall2(i32 inreg %a, i32 inreg %b) 183 define void @cdecl_fastcall_tail(i32 %a, i32 %b) { 184 tail call x86_fastcallcc void @fastcall2(i32 %a, i32 %b) 185 ret void 186 } 187 ; fastcall2 won't pop anything. 188 ; CHECK-LABEL: cdecl_fastcall_tail 189 ; CHECK: jmp fastcall2 190
