Author: theraven
Date: Tue Aug 7 05:02:46 2018
New Revision: 339128
URL: http://llvm.org/viewvc/llvm-project?rev=339128&view=rev
Log:
[objc-gnustep] Don't emit .guess ivar offset vars.
These were intended to allow non-fragile and fragile ABI code to be
mixed, as long as the fragile classes were higher up the hierarchy than
the non-fragile ones. Unfortunately:
- No one actually wants to do this.
- Recent versions of Linux's run-time linker break it.
Modified:
cfe/trunk/lib/CodeGen/CGObjCGNU.cpp
Modified: cfe/trunk/lib/CodeGen/CGObjCGNU.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGObjCGNU.cpp?rev=339128&r1=339127&r2=339128&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGObjCGNU.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGObjCGNU.cpp Tue Aug 7 05:02:46 2018
@@ -3812,40 +3812,10 @@ llvm::GlobalVariable *CGObjCGNU::ObjCIva
// is. This allows code compiled with non-fragile ivars to work correctly
// when linked against code which isn't (most of the time).
llvm::GlobalVariable *IvarOffsetPointer = TheModule.getNamedGlobal(Name);
- if (!IvarOffsetPointer) {
- // This will cause a run-time crash if we accidentally use it. A value of
- // 0 would seem more sensible, but will silently overwrite the isa pointer
- // causing a great deal of confusion.
- uint64_t Offset = -1;
- // We can't call ComputeIvarBaseOffset() here if we have the
- // implementation, because it will create an invalid ASTRecordLayout object
- // that we are then stuck with forever, so we only initialize the ivar
- // offset variable with a guess if we only have the interface. The
- // initializer will be reset later anyway, when we are generating the class
- // description.
- if (!CGM.getContext().getObjCImplementation(
- const_cast<ObjCInterfaceDecl *>(ID)))
- Offset = ComputeIvarBaseOffset(CGM, ID, Ivar);
-
- llvm::ConstantInt *OffsetGuess = llvm::ConstantInt::get(Int32Ty, Offset,
- /*isSigned*/true);
- // Don't emit the guess in non-PIC code because the linker will not be able
- // to replace it with the real version for a library. In non-PIC code you
- // must compile with the fragile ABI if you want to use ivars from a
- // GCC-compiled class.
- if (CGM.getLangOpts().PICLevel) {
- llvm::GlobalVariable *IvarOffsetGV = new llvm::GlobalVariable(TheModule,
- Int32Ty, false,
- llvm::GlobalValue::PrivateLinkage, OffsetGuess, Name+".guess");
- IvarOffsetPointer = new llvm::GlobalVariable(TheModule,
- IvarOffsetGV->getType(), false,
llvm::GlobalValue::LinkOnceAnyLinkage,
- IvarOffsetGV, Name);
- } else {
- IvarOffsetPointer = new llvm::GlobalVariable(TheModule,
- llvm::Type::getInt32PtrTy(VMContext), false,
- llvm::GlobalValue::ExternalLinkage, nullptr, Name);
- }
- }
+ if (!IvarOffsetPointer)
+ IvarOffsetPointer = new llvm::GlobalVariable(TheModule,
+ llvm::Type::getInt32PtrTy(VMContext), false,
+ llvm::GlobalValue::ExternalLinkage, nullptr, Name);
return IvarOffsetPointer;
}
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
