"Attribute 'builtin' can only be applied to a callsite.", &F);
// Check that this function meets the restrictions on this calling convention.
+ // Sometimes varargs is used for perfectly forwarding thunks, so some of these
+ // restrictions can be lifted.
switch (F.getCallingConv()) {
default:
- break;
case CallingConv::C:
break;
case CallingConv::Fast:
case CallingConv::Cold:
- case CallingConv::X86_FastCall:
- case CallingConv::X86_ThisCall:
case CallingConv::Intel_OCL_BI:
case CallingConv::PTX_Kernel:
case CallingConv::PTX_Device:
- Assert1(!F.isVarArg(),
- "Varargs functions must have C calling conventions!", &F);
+ Assert1(!F.isVarArg(), "Calling convention does not support varargs or "
+ "perfect forwarding!", &F);
break;
}
--- /dev/null
+; RUN: llc -mtriple=i686-pc-windows < %s | FileCheck %s
+
+target datalayout = "e-m:w-p:32:32-i64:64-f80:32-n8:16:32-S32"
+
+declare x86_thiscallcc void @thiscall_thunk(i8* %this, ...)
+define i32 @call_varargs_thiscall_thunk(i8* %a, i32 %b, i32 %c, i32 %d) {
+ call x86_thiscallcc void (i8*, ...)* @thiscall_thunk(i8* %a, i32 1, i32 2)
+ call x86_thiscallcc void (i8*, ...)* @thiscall_thunk(i8* %a, i32 1, i32 2)
+ %t1 = add i32 %b, %c
+ %r = add i32 %t1, %d
+ ret i32 %r
+}
+
+; CHECK: _call_varargs_thiscall_thunk:
+; CHECK: calll _thiscall_thunk
+; CHECK-NEXT: subl $8, %esp
+
+; We don't mangle the argument size into variadic callee cleanup functions.
+
+declare x86_stdcallcc void @stdcall_thunk(i8* %this, ...)
+define i32 @call_varargs_stdcall_thunk(i8* %a, i32 %b, i32 %c, i32 %d) {
+ call x86_stdcallcc void (i8*, ...)* @stdcall_thunk(i8* %a, i32 1, i32 2)
+ call x86_stdcallcc void (i8*, ...)* @stdcall_thunk(i8* %a, i32 1, i32 2)
+ %t1 = add i32 %b, %c
+ %r = add i32 %t1, %d
+ ret i32 %r
+}
+
+; CHECK: _call_varargs_stdcall_thunk:
+; CHECK: calll _stdcall_thunk{{$}}
+; CHECK-NEXT: subl $12, %esp
+
+declare x86_fastcallcc void @fastcall_thunk(i8* %this, ...)
+define i32 @call_varargs_fastcall_thunk(i8* %a, i32 %b, i32 %c, i32 %d) {
+ call x86_fastcallcc void (i8*, ...)* @fastcall_thunk(i8* inreg %a, i32 inreg 1, i32 2)
+ call x86_fastcallcc void (i8*, ...)* @fastcall_thunk(i8* inreg %a, i32 inreg 1, i32 2)
+ %t1 = add i32 %b, %c
+ %r = add i32 %t1, %d
+ ret i32 %r
+}
+
+; CHECK: _call_varargs_fastcall_thunk:
+; CHECK: calll @fastcall_thunk{{$}}
+; CHECK-NEXT: subl $4, %esp
+
+; If you actually return from such a thunk, it will only pop the non-variadic
+; portion of the arguments, which is different from what the callee passes.
+
+define x86_stdcallcc void @varargs_stdcall_return(i32, i32, ...) {
+ ret void
+}
+
+; CHECK: _varargs_stdcall_return:
+; CHECK: retl $8
%w = bitcast i8* %v to i32*
ret i32* %w
}
+
+declare x86_thiscallcc void @varargs_thiscall(i8*, ...)
+define x86_thiscallcc void @varargs_thiscall_thunk(i8* %this, ...) {
+ musttail call x86_thiscallcc void (i8*, ...)* @varargs_thiscall(i8* %this, ...)
+ ret void
+}
+
+declare x86_fastcallcc void @varargs_fastcall(i8*, ...)
+define x86_fastcallcc void @varargs_fastcall_thunk(i8* %this, ...) {
+ musttail call x86_fastcallcc void (i8*, ...)* @varargs_fastcall(i8* %this, ...)
+ ret void
+}
+
+define x86_thiscallcc void @varargs_thiscall_unreachable(i8* %this, ...) {
+ unreachable
+}
+
+define x86_thiscallcc void @varargs_thiscall_ret_unreachable(i8* %this, ...) {
+ musttail call x86_thiscallcc void (i8*, ...)* @varargs_thiscall(i8* %this, ...)
+ ret void
+bb1:
+ ret void
+}