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[MS ABI] Allow fastcall member function pointers to get CodeGen'd 

This restriction appears unnecessary and most likely came about during
early work for musttail.

llvm-svn: 239500
This commit is contained in:
David Majnemer 2015-06-11 00:45:44 +00:00
parent 01b9bb42d4
commit ac936ff5ab
2 changed files with 18 additions and 19 deletions
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23
clang/lib/CodeGen/MicrosoftCXXABI.cpp
View File

@ -2423,20 +2423,15 @@ MicrosoftCXXABI::BuildMemberPointer(const CXXRecordDecl *RD,
FirstField = CGM.GetAddrOfFunction(MD, Ty);
FirstField = llvm::ConstantExpr::getBitCast(FirstField, CGM.VoidPtrTy);
} else {
if (FPT->getCallConv() == CC_X86FastCall) {
CGM.ErrorUnsupported(MD, "pointer to fastcall virtual member function");
FirstField = llvm::Constant::getNullValue(CGM.VoidPtrTy);
} else {
auto &VTableContext = CGM.getMicrosoftVTableContext();
MicrosoftVTableContext::MethodVFTableLocation ML =
VTableContext.getMethodVFTableLocation(MD);
llvm::Function *Thunk = EmitVirtualMemPtrThunk(MD, ML);
FirstField = llvm::ConstantExpr::getBitCast(Thunk, CGM.VoidPtrTy);
// Include the vfptr adjustment if the method is in a non-primary vftable.
NonVirtualBaseAdjustment += ML.VFPtrOffset;
if (ML.VBase)
VBTableIndex = VTableContext.getVBTableIndex(RD, ML.VBase) * 4;
}
auto &VTableContext = CGM.getMicrosoftVTableContext();
MicrosoftVTableContext::MethodVFTableLocation ML =
VTableContext.getMethodVFTableLocation(MD);
llvm::Function *Thunk = EmitVirtualMemPtrThunk(MD, ML);
FirstField = llvm::ConstantExpr::getBitCast(Thunk, CGM.VoidPtrTy);
// Include the vfptr adjustment if the method is in a non-primary vftable.
NonVirtualBaseAdjustment += ML.VFPtrOffset;
if (ML.VBase)
VBTableIndex = VTableContext.getVBTableIndex(RD, ML.VBase) * 4;
}
// The rest of the fields are common with data member pointers.

14
clang/test/CodeGenCXX/microsoft-abi-vmemptr-fastcall.cpp
View File

@ -1,11 +1,15 @@
// RUN: %clang_cc1 -fms-extensions -triple i686-pc-windows-msvc %s -emit-llvm-only -verify
// We reject this because LLVM doesn't forward the second regparm through the
// thunk.
// RUN: %clang_cc1 -fms-extensions -triple i686-pc-windows-msvc %s -emit-llvm -o - | FileCheck %s
struct A {
virtual void __fastcall f(int a, int b); // expected-error {{cannot compile this pointer to fastcall virtual member function yet}}
virtual void __fastcall f(int a, int b);
};
void (__fastcall A::*doit())(int, int) {
return &A::f;
}
// CHECK: define linkonce_odr x86_fastcallcc void @"\01??_9A@@$BA@AI"(%struct.A* inreg %this, ...) {{.*}} comdat align 2 {
// CHECK: [[VPTR:%.*]] = getelementptr inbounds void (%struct.A*, ...)*, void (%struct.A*, ...)** %vtable, i64 0
// CHECK: [[CALLEE:%.*]] = load void (%struct.A*, ...)*, void (%struct.A*, ...)** [[VPTR]]
// CHECK: musttail call x86_fastcallcc void (%struct.A*, ...) [[CALLEE]](%struct.A* inreg %{{.*}}, ...)
// CHECK: ret void
// CHECK: }