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Fix mingw32 thiscall + sret. 

Unlike msvc, when handling a thiscall + sret gcc will
* Put the sret in %ecx
* Put the this pointer is (%esp)

This fixes, for example, calling stringstream::str.

llvm-svn: 196312
This commit is contained in:
Rafael Espindola 2013-12-03 20:51:23 +00:00
parent 88d8695ab4
commit 0a2baf8eaf
2 changed files with 49 additions and 5 deletions
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26
llvm/lib/Target/X86/X86CallingConv.td
View File

@ -453,18 +453,34 @@ def CC_X86_32_FastCall : CallingConv<[
CCDelegateTo<CC_X86_32_Common>
]>;
def CC_X86_32_ThisCall : CallingConv<[
def CC_X86_32_ThisCall_Common : CallingConv<[
// The first integer argument is passed in ECX
CCIfType<[i32], CCAssignToReg<[ECX]>>,
// Otherwise, same as everything else.
CCDelegateTo<CC_X86_32_Common>
]>;
def CC_X86_32_ThisCall_Mingw : CallingConv<[
// Promote i8/i16 arguments to i32.
CCIfType<[i8, i16], CCPromoteToType<i32>>,
CCDelegateTo<CC_X86_32_ThisCall_Common>
]>;
def CC_X86_32_ThisCall_Win : CallingConv<[
// Promote i8/i16 arguments to i32.
CCIfType<[i8, i16], CCPromoteToType<i32>>,
// Pass sret arguments indirectly through stack.
CCIfSRet<CCAssignToStack<4, 4>>,
// The first integer argument is passed in ECX
CCIfType<[i32], CCAssignToReg<[ECX]>>,
CCDelegateTo<CC_X86_32_ThisCall_Common>
]>;
// Otherwise, same as everything else.
CCDelegateTo<CC_X86_32_Common>
def CC_X86_32_ThisCall : CallingConv<[
CCIfSubtarget<"isTargetCygMing()", CCDelegateTo<CC_X86_32_ThisCall_Mingw>>,
CCDelegateTo<CC_X86_32_ThisCall_Win>
]>;
def CC_X86_32_FastCC : CallingConv<[

28
llvm/test/CodeGen/X86/win32_sret.ll
View File

@ -124,3 +124,31 @@ entry:
; WIN32: ret
ret void
}
%struct.test6 = type { i32, i32, i32 }
define void @test6_f(%struct.test6* %x) nounwind {
; WIN32-LABEL: _test6_f:
; MINGW_X86-LABEL: _test6_f:
; The %x argument is moved to %ecx. It will be the this pointer.
; WIN32: movl 8(%ebp), %ecx
; The %x argument is moved to (%esp). It will be the this pointer. With -O0
; we copy esp to ecx and use (ecx) instead of (esp).
; MINGW_X86: movl 8(%ebp), %eax
; MINGW_X86: movl %eax, (%e{{([a-d]x)|(sp)}})
; The sret pointer is (%esp)
; WIN32: leal 8(%esp), %[[REG:e[a-d]x]]
; WIN32-NEXT: movl %[[REG]], (%e{{([a-d]x)|(sp)}})
; The sret pointer is %ecx
; MINGW_X86-NEXT: leal 8(%esp), %ecx
; MINGW_X86-NEXT: calll _test6_g
%tmp = alloca %struct.test6, align 4
call x86_thiscallcc void @test6_g(%struct.test6* sret %tmp, %struct.test6* %x)
ret void
}
declare x86_thiscallcc void @test6_g(%struct.test6* sret, %struct.test6*)