> On Feb 26, 2015, at 12:08 PM, John McCall <[email protected]> wrote: > >> On Feb 25, 2015, at 3:48 PM, Larisse Voufo <[email protected]> wrote: >> Author: lvoufo >> Date: Wed Feb 25 17:48:43 2015 >> New Revision: 230580 >> >> URL: http://llvm.org/viewvc/llvm-project?rev=230580&view=rev >> Log: >> Improvement on sized deallocation from r230160: >> Do not declare sized deallocation functions dependently on whether it is >> found in global scope. Instead, enforce the branching in emitted code by (1) >> declaring the functions extern_weak and (2) emitting sized delete >> expressions as a branching between both forms delete. >> >> Modified: >> cfe/trunk/lib/CodeGen/CGExprCXX.cpp >> cfe/trunk/lib/Sema/SemaExprCXX.cpp >> cfe/trunk/test/CodeGenCXX/cxx1y-sized-deallocation.cpp >> cfe/trunk/test/CodeGenCXX/implicit-allocation-functions.cpp >> cfe/trunk/test/CodeGenCXX/pr21754.cpp >> >> Modified: cfe/trunk/lib/CodeGen/CGExprCXX.cpp >> URL: >> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGExprCXX.cpp?rev=230580&r1=230579&r2=230580&view=diff >> ============================================================================== >> --- cfe/trunk/lib/CodeGen/CGExprCXX.cpp (original) >> +++ cfe/trunk/lib/CodeGen/CGExprCXX.cpp Wed Feb 25 17:48:43 2015 >> @@ -1422,6 +1422,71 @@ CodeGenFunction::pushCallObjectDeleteCle >> OperatorDelete, ElementType); >> } >> >> +static void EmitDelete(CodeGenFunction &CGF, >> + const CXXDeleteExpr *DE, >> + llvm::Value *Ptr, >> + QualType ElementType); >> + >> +static void EmitSizedDelete(CodeGenFunction &CGF, >> + const CXXDeleteExpr *DE, >> + llvm::Value *Ptr, >> + QualType ElementType, >> + FunctionDecl* UnsizedDealloc) { >> + >> + if (CGF.getLangOpts().DefineSizedDeallocation) { >> + // The delete operator in use is fixed. So simply emit the delete expr. >> + EmitDelete(CGF, DE, Ptr, ElementType); >> + return; >> + } >> + >> + assert(UnsizedDealloc && "We must be emiting a 'sized' delete expr"); >> + >> + // Branch off over the value of operator delete: >> + // Use the sized form if available, and default on the unsized form >> otherwise. >> + llvm::BasicBlock *ThenBlock = CGF.createBasicBlock("if.then"); >> + llvm::BasicBlock *ContBlock = CGF.createBasicBlock("if.end"); >> + llvm::BasicBlock *ElseBlock = CGF.createBasicBlock("if.else"); >> + >> + // Emit the condition. >> + const FunctionDecl *OpDelFD = DE->getOperatorDelete(); >> + llvm::Value *OpDelAddr = CGF.CGM.GetAddrOfFunction(OpDelFD); >> + //llvm::Function *OpDel = dyn_cast<llvm::Function>(OpDelAddr); >> + llvm::Value *SDE = CGF.Builder.CreateIsNotNull(OpDelAddr, >> "sized.del.exists"); >> + CGF.Builder.CreateCondBr(SDE, ThenBlock, ElseBlock); >> + >> + // Emit the 'then' code. >> + CGF.EmitBlock(ThenBlock); >> + EmitDelete(CGF, DE, Ptr, ElementType); >> + CGF.EmitBranch(ContBlock); >> + >> + // Compute the 'unsized' delete expr. >> + CXXDeleteExpr * E = const_cast<CXXDeleteExpr*>(DE); >> + CXXDeleteExpr *UnsizedDE = >> + new (CGF.getContext()) CXXDeleteExpr(CGF.getContext().VoidTy, >> + E->isGlobalDelete(), >> + E->isArrayForm(), >> + E->isArrayFormAsWritten(), >> + E->doesUsualArrayDeleteWantSize(), >> + UnsizedDealloc, >> + E->getArgument(), >> + E->getLocStart()); > > Instead of doing it this way, please introduce a common function to call > from EmitDeleteCall and the CallArrayDelete cleanup. > > Doing it this way unnecessarily clones the object / array destruction code, > causes a useless branch when making a virtual call to the deleting destructor, > and fails to branch appropriately within a deleting destructor. > > The common function will also be a natural place in the future to check the > language that elides the dynamic check and assumes that the sized > deallocation function exists. (The reverse option will be implemented by > having Sema just specify an unsized deallocation function.)
Ping. John. _______________________________________________ cfe-commits mailing list [email protected] http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
