Fix SRet for thiscall in i686-pc-win32

llvm-svn: 178634

llvm/lib/Target/X86/X86CallingConv.td

@@ -387,8 +387,8 @@ def CC_X86_32_ThisCall : CallingConv<[
   // Promote i8/i16 arguments to i32.
   CCIfType<[i8, i16], CCPromoteToType<i32>>,
 
-  // Pass sret arguments indirectly through EAX
+  // Pass sret arguments indirectly through stack.
-  CCIfSRet<CCAssignToReg<[EAX]>>,
+  CCIfSRet<CCAssignToStack<4, 4>>,
 
   // The first integer argument is passed in ECX
   CCIfType<[i32], CCAssignToReg<[ECX]>>,

llvm/test/CodeGen/X86/thiscall-struct-return.ll

@@ -1,47 +0,0 @@
-; RUN: llc < %s -mtriple=i386-PC-Win32 | FileCheck %s
-
-%class.C = type { i8 }
-%struct.S = type { i32 }
-%struct.M = type { i32, i32 }
-
-declare void @_ZN1CC1Ev(%class.C* %this) unnamed_addr nounwind align 2
-declare x86_thiscallcc void @_ZNK1C5SmallEv(%struct.S* noalias sret %agg.result, %class.C* %this) nounwind align 2
-declare x86_thiscallcc void @_ZNK1C6MediumEv(%struct.M* noalias sret %agg.result, %class.C* %this) nounwind align 2
-
-define void @testv() nounwind {
-; CHECK: testv:
-; CHECK: leal 16(%esp), %esi
-; CHECK-NEXT: movl	%esi, (%esp)
-; CHECK-NEXT: calll _ZN1CC1Ev
-; CHECK: leal 8(%esp), %eax
-; CHECK-NEXT: movl %esi, %ecx
-; CHECK-NEXT: calll _ZNK1C5SmallEv
-entry:
-  %c = alloca %class.C, align 1
-  %tmp = alloca %struct.S, align 4
-  call void @_ZN1CC1Ev(%class.C* %c)
-  ; This call should put the return structure as a pointer
-  ; into EAX instead of returning directly in EAX.  The this
-  ; pointer should go into ECX
-  call x86_thiscallcc void @_ZNK1C5SmallEv(%struct.S* sret %tmp, %class.C* %c)
-  ret void
-}
-
-define void @test2v() nounwind {
-; CHECK: test2v:
-; CHECK: leal 16(%esp), %esi
-; CHECK-NEXT: movl	%esi, (%esp)
-; CHECK-NEXT: calll _ZN1CC1Ev
-; CHECK: leal 8(%esp), %eax
-; CHECK-NEXT: movl %esi, %ecx
-; CHECK-NEXT: calll _ZNK1C6MediumEv
-entry:
-  %c = alloca %class.C, align 1
-  %tmp = alloca %struct.M, align 4
-  call void @_ZN1CC1Ev(%class.C* %c)
-  ; This call should put the return structure as a pointer
-  ; into EAX instead of returning directly in EAX/EDX.  The this
-  ; pointer should go into ECX
-  call x86_thiscallcc void @_ZNK1C6MediumEv(%struct.M* sret %tmp, %class.C* %c)
-  ret void
-}

llvm/test/CodeGen/X86/win32_sret.ll

@@ -82,3 +82,43 @@ entry:
   store i32 42, i32* %x, align 4
   ret void
 }
+
+%struct.S5 = type { i32 }
+%class.C5 = type { i8 }
+
+define x86_thiscallcc void @"\01?foo@C5@@QAE?AUS5@@XZ"(%struct.S5* noalias sret %agg.result, %class.C5* %this) {
+entry:
+  %this.addr = alloca %class.C5*, align 4
+  store %class.C5* %this, %class.C5** %this.addr, align 4
+  %this1 = load %class.C5** %this.addr
+  %x = getelementptr inbounds %struct.S5* %agg.result, i32 0, i32 0
+  store i32 42, i32* %x, align 4
+  ret void
+; WIN32:     {{^}}"?foo@C5@@QAE?AUS5@@XZ":
+
+; The address of the return structure is passed as an implicit parameter.
+; In the -O0 build, %eax is spilled at the beginning of the function, hence we
+; should match both 4(%esp) and 8(%esp).
+; WIN32:     {{[48]}}(%esp), %eax
+; WIN32:     movl $42, (%eax)
+; WIN32:     ret $4
+}
+
+define void @call_foo5() {
+entry:
+  %c = alloca %class.C5, align 1
+  %s = alloca %struct.S5, align 4
+  call x86_thiscallcc void @"\01?foo@C5@@QAE?AUS5@@XZ"(%struct.S5* sret %s, %class.C5* %c)
+; WIN32:      {{^}}_call_foo5:
+
+; Load the address of the result and put it onto stack
+; (through %ecx in the -O0 build).
+; WIN32:      leal {{[0-9]+}}(%esp), %eax
+; WIN32:      movl %eax, (%e{{[sc][px]}})
+
+; The this pointer goes to ECX.
+; WIN32-NEXT: leal {{[0-9]+}}(%esp), %ecx
+; WIN32-NEXT: calll "?foo@C5@@QAE?AUS5@@XZ"
+; WIN32:      ret
+  ret void
+}