It looks like this breaks building base.dll in the Chromium project: http://code.google.com/p/chromium/issues/detail?id=505916
On Tue, Jun 30, 2015 at 12:07 PM, Peter Collingbourne <pe...@pcc.me.uk> wrote: > Author: pcc > Date: Tue Jun 30 14:07:26 2015 > New Revision: 241102 > > URL: http://llvm.org/viewvc/llvm-project?rev=241102&view=rev > Log: > CodeGen: Assign an appropriate comdat to thunks. > > Previously we were not assigning a comdat to thunks in the Microsoft ABI, > which would have required us to emit these functions outside of a comdat. > (Due to an inconsistency in how we were emitting objects, we were getting > this > right most of the time, but only when compiling with function sections.) > This > code generator change causes us to create a comdat for each thunk. > > Differential Revision: http://reviews.llvm.org/D10829 > > Modified: > cfe/trunk/lib/CodeGen/CGVTables.cpp > cfe/trunk/test/CodeGenCXX/microsoft-abi-thunks.cpp > > Modified: cfe/trunk/lib/CodeGen/CGVTables.cpp > URL: > http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGVTables.cpp?rev=241102&r1=241101&r2=241102&view=diff > > ============================================================================== > --- cfe/trunk/lib/CodeGen/CGVTables.cpp (original) > +++ cfe/trunk/lib/CodeGen/CGVTables.cpp Tue Jun 30 14:07:26 2015 > @@ -378,9 +378,6 @@ void CodeGenFunction::GenerateThunk(llvm > // Set the right linkage. > CGM.setFunctionLinkage(GD, Fn); > > - if (CGM.supportsCOMDAT() && Fn->isWeakForLinker()) > - Fn->setComdat(CGM.getModule().getOrInsertComdat(Fn->getName())); > - > // Set the right visibility. > const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl()); > setThunkVisibility(CGM, MD, Thunk, Fn); > @@ -450,17 +447,18 @@ void CodeGenVTables::emitThunk(GlobalDec > // expensive/sucky at the moment, so don't generate the thunk unless > // we have to. > // FIXME: Do something better here; GenerateVarArgsThunk is extremely > ugly. > - if (!UseAvailableExternallyLinkage) { > - CodeGenFunction(CGM).GenerateVarArgsThunk(ThunkFn, FnInfo, GD, > Thunk); > - CGM.getCXXABI().setThunkLinkage(ThunkFn, ForVTable, GD, > - !Thunk.Return.isEmpty()); > - } > + if (UseAvailableExternallyLinkage) > + return; > + CodeGenFunction(CGM).GenerateVarArgsThunk(ThunkFn, FnInfo, GD, Thunk); > } else { > // Normal thunk body generation. > CodeGenFunction(CGM).GenerateThunk(ThunkFn, FnInfo, GD, Thunk); > - CGM.getCXXABI().setThunkLinkage(ThunkFn, ForVTable, GD, > - !Thunk.Return.isEmpty()); > } > + > + CGM.getCXXABI().setThunkLinkage(ThunkFn, ForVTable, GD, > + !Thunk.Return.isEmpty()); > + if (CGM.supportsCOMDAT() && ThunkFn->isWeakForLinker()) > + > ThunkFn->setComdat(CGM.getModule().getOrInsertComdat(ThunkFn->getName())); > } > > void CodeGenVTables::maybeEmitThunkForVTable(GlobalDecl GD, > > Modified: cfe/trunk/test/CodeGenCXX/microsoft-abi-thunks.cpp > URL: > http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/microsoft-abi-thunks.cpp?rev=241102&r1=241101&r2=241102&view=diff > > ============================================================================== > --- cfe/trunk/test/CodeGenCXX/microsoft-abi-thunks.cpp (original) > +++ cfe/trunk/test/CodeGenCXX/microsoft-abi-thunks.cpp Tue Jun 30 14:07:26 > 2015 > @@ -91,7 +91,7 @@ struct E : D { > > E::E() {} // Emits vftable and forces thunk generation. > > -// CODEGEN-LABEL: define weak_odr x86_thiscallcc %struct.C* @"\01?goo@E > @@QAEPAUB@@XZ" > +// CODEGEN-LABEL: define weak_odr x86_thiscallcc %struct.C* @"\01?goo@E > @@QAEPAUB@@XZ"{{.*}} comdat > // CODEGEN: call x86_thiscallcc %struct.C* @"\01?goo@E@@UAEPAUC@@XZ" > // CODEGEN: getelementptr inbounds i8, i8* {{.*}}, i32 4 > // CODEGEN: ret > @@ -124,7 +124,7 @@ struct I : D { > > I::I() {} // Emits vftable and forces thunk generation. > > -// CODEGEN-LABEL: define weak_odr x86_thiscallcc %struct.{{[BF]}}* > @"\01?goo@I@@QAEPAUB@@XZ" > +// CODEGEN-LABEL: define weak_odr x86_thiscallcc %struct.{{[BF]}}* > @"\01?goo@I@@QAEPAUB@@XZ"{{.*}} comdat > // CODEGEN: %[[ORIG_RET:.*]] = call x86_thiscallcc %struct.F* @"\01?goo@I > @@UAEPAUF@@XZ" > // CODEGEN: %[[ORIG_RET_i8:.*]] = bitcast %struct.F* %[[ORIG_RET]] to i8* > // CODEGEN: %[[VBPTR_i8:.*]] = getelementptr inbounds i8, i8* > %[[ORIG_RET_i8]], i32 4 > > > _______________________________________________ > cfe-commits mailing list > cfe-commits@cs.uiuc.edu > http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits >
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