diff options
Diffstat (limited to 'contrib/llvm/tools/clang/lib/CodeGen/CodeGenFunction.cpp')
| -rw-r--r-- | contrib/llvm/tools/clang/lib/CodeGen/CodeGenFunction.cpp | 801 |
1 files changed, 598 insertions, 203 deletions
diff --git a/contrib/llvm/tools/clang/lib/CodeGen/CodeGenFunction.cpp b/contrib/llvm/tools/clang/lib/CodeGen/CodeGenFunction.cpp index 73de0fd..eb6c436 100644 --- a/contrib/llvm/tools/clang/lib/CodeGen/CodeGenFunction.cpp +++ b/contrib/llvm/tools/clang/lib/CodeGen/CodeGenFunction.cpp @@ -14,13 +14,16 @@ #include "CodeGenFunction.h" #include "CodeGenModule.h" #include "CGDebugInfo.h" +#include "CGException.h" #include "clang/Basic/TargetInfo.h" #include "clang/AST/APValue.h" #include "clang/AST/ASTContext.h" #include "clang/AST/Decl.h" #include "clang/AST/DeclCXX.h" #include "clang/AST/StmtCXX.h" +#include "clang/Frontend/CodeGenOptions.h" #include "llvm/Target/TargetData.h" +#include "llvm/Intrinsics.h" using namespace clang; using namespace CodeGen; @@ -28,13 +31,20 @@ CodeGenFunction::CodeGenFunction(CodeGenModule &cgm) : BlockFunction(cgm, *this, Builder), CGM(cgm), Target(CGM.getContext().Target), Builder(cgm.getModule().getContext()), - DebugInfo(0), IndirectBranch(0), + ExceptionSlot(0), DebugInfo(0), IndirectBranch(0), SwitchInsn(0), CaseRangeBlock(0), InvokeDest(0), + DidCallStackSave(false), UnreachableBlock(0), CXXThisDecl(0), CXXThisValue(0), CXXVTTDecl(0), CXXVTTValue(0), - ConditionalBranchLevel(0), TerminateHandler(0), TrapBB(0), - UniqueAggrDestructorCount(0) { - LLVMIntTy = ConvertType(getContext().IntTy); + ConditionalBranchLevel(0), TerminateLandingPad(0), TerminateHandler(0), + TrapBB(0) { + + // Get some frequently used types. LLVMPointerWidth = Target.getPointerWidth(0); + llvm::LLVMContext &LLVMContext = CGM.getLLVMContext(); + IntPtrTy = llvm::IntegerType::get(LLVMContext, LLVMPointerWidth); + Int32Ty = llvm::Type::getInt32Ty(LLVMContext); + Int64Ty = llvm::Type::getInt64Ty(LLVMContext); + Exceptions = getContext().getLangOptions().Exceptions; CatchUndefined = getContext().getLangOptions().CatchUndefined; CGM.getMangleContext().startNewFunction(); @@ -45,14 +55,6 @@ ASTContext &CodeGenFunction::getContext() const { } -llvm::BasicBlock *CodeGenFunction::getBasicBlockForLabel(const LabelStmt *S) { - llvm::BasicBlock *&BB = LabelMap[S]; - if (BB) return BB; - - // Create, but don't insert, the new block. - return BB = createBasicBlock(S->getName()); -} - llvm::Value *CodeGenFunction::GetAddrOfLocalVar(const VarDecl *VD) { llvm::Value *Res = LocalDeclMap[VD]; assert(Res && "Invalid argument to GetAddrOfLocalVar(), no decl!"); @@ -87,25 +89,26 @@ void CodeGenFunction::EmitReturnBlock() { // We have a valid insert point, reuse it if it is empty or there are no // explicit jumps to the return block. - if (CurBB->empty() || ReturnBlock->use_empty()) { - ReturnBlock->replaceAllUsesWith(CurBB); - delete ReturnBlock; + if (CurBB->empty() || ReturnBlock.Block->use_empty()) { + ReturnBlock.Block->replaceAllUsesWith(CurBB); + delete ReturnBlock.Block; } else - EmitBlock(ReturnBlock); + EmitBlock(ReturnBlock.Block); return; } // Otherwise, if the return block is the target of a single direct // branch then we can just put the code in that block instead. This // cleans up functions which started with a unified return block. - if (ReturnBlock->hasOneUse()) { + if (ReturnBlock.Block->hasOneUse()) { llvm::BranchInst *BI = - dyn_cast<llvm::BranchInst>(*ReturnBlock->use_begin()); - if (BI && BI->isUnconditional() && BI->getSuccessor(0) == ReturnBlock) { + dyn_cast<llvm::BranchInst>(*ReturnBlock.Block->use_begin()); + if (BI && BI->isUnconditional() && + BI->getSuccessor(0) == ReturnBlock.Block) { // Reset insertion point and delete the branch. Builder.SetInsertPoint(BI->getParent()); BI->eraseFromParent(); - delete ReturnBlock; + delete ReturnBlock.Block; return; } } @@ -114,29 +117,37 @@ void CodeGenFunction::EmitReturnBlock() { // unless it has uses. However, we still need a place to put the debug // region.end for now. - EmitBlock(ReturnBlock); + EmitBlock(ReturnBlock.Block); +} + +static void EmitIfUsed(CodeGenFunction &CGF, llvm::BasicBlock *BB) { + if (!BB) return; + if (!BB->use_empty()) + return CGF.CurFn->getBasicBlockList().push_back(BB); + delete BB; } void CodeGenFunction::FinishFunction(SourceLocation EndLoc) { assert(BreakContinueStack.empty() && "mismatched push/pop in break/continue stack!"); - assert(BlockScopes.empty() && - "did not remove all blocks from block scope map!"); - assert(CleanupEntries.empty() && - "mismatched push/pop in cleanup stack!"); // Emit function epilog (to return). EmitReturnBlock(); + EmitFunctionInstrumentation("__cyg_profile_func_exit"); + // Emit debug descriptor for function end. if (CGDebugInfo *DI = getDebugInfo()) { DI->setLocation(EndLoc); DI->EmitRegionEnd(CurFn, Builder); } - EmitFunctionEpilog(*CurFnInfo, ReturnValue); + EmitFunctionEpilog(*CurFnInfo); EmitEndEHSpec(CurCodeDecl); + assert(EHStack.empty() && + "did not remove all scopes from cleanup stack!"); + // If someone did an indirect goto, emit the indirect goto block at the end of // the function. if (IndirectBranch) { @@ -158,6 +169,53 @@ void CodeGenFunction::FinishFunction(SourceLocation EndLoc) { PN->eraseFromParent(); } } + + EmitIfUsed(*this, TerminateLandingPad); + EmitIfUsed(*this, TerminateHandler); + EmitIfUsed(*this, UnreachableBlock); + + if (CGM.getCodeGenOpts().EmitDeclMetadata) + EmitDeclMetadata(); +} + +/// ShouldInstrumentFunction - Return true if the current function should be +/// instrumented with __cyg_profile_func_* calls +bool CodeGenFunction::ShouldInstrumentFunction() { + if (!CGM.getCodeGenOpts().InstrumentFunctions) + return false; + if (CurFuncDecl->hasAttr<NoInstrumentFunctionAttr>()) + return false; + return true; +} + +/// EmitFunctionInstrumentation - Emit LLVM code to call the specified +/// instrumentation function with the current function and the call site, if +/// function instrumentation is enabled. +void CodeGenFunction::EmitFunctionInstrumentation(const char *Fn) { + if (!ShouldInstrumentFunction()) + return; + + const llvm::PointerType *PointerTy; + const llvm::FunctionType *FunctionTy; + std::vector<const llvm::Type*> ProfileFuncArgs; + + // void __cyg_profile_func_{enter,exit} (void *this_fn, void *call_site); + PointerTy = llvm::Type::getInt8PtrTy(VMContext); + ProfileFuncArgs.push_back(PointerTy); + ProfileFuncArgs.push_back(PointerTy); + FunctionTy = llvm::FunctionType::get( + llvm::Type::getVoidTy(VMContext), + ProfileFuncArgs, false); + + llvm::Constant *F = CGM.CreateRuntimeFunction(FunctionTy, Fn); + llvm::CallInst *CallSite = Builder.CreateCall( + CGM.getIntrinsic(llvm::Intrinsic::returnaddress, 0, 0), + llvm::ConstantInt::get(Int32Ty, 0), + "callsite"); + + Builder.CreateCall2(F, + llvm::ConstantExpr::getBitCast(CurFn, PointerTy), + CallSite); } void CodeGenFunction::StartFunction(GlobalDecl GD, QualType RetTy, @@ -187,14 +245,12 @@ void CodeGenFunction::StartFunction(GlobalDecl GD, QualType RetTy, // Create a marker to make it easy to insert allocas into the entryblock // later. Don't create this with the builder, because we don't want it // folded. - llvm::Value *Undef = llvm::UndefValue::get(llvm::Type::getInt32Ty(VMContext)); - AllocaInsertPt = new llvm::BitCastInst(Undef, - llvm::Type::getInt32Ty(VMContext), "", - EntryBB); + llvm::Value *Undef = llvm::UndefValue::get(Int32Ty); + AllocaInsertPt = new llvm::BitCastInst(Undef, Int32Ty, "", EntryBB); if (Builder.isNamePreserving()) AllocaInsertPt->setName("allocapt"); - ReturnBlock = createBasicBlock("return"); + ReturnBlock = getJumpDestInCurrentScope("return"); Builder.SetInsertPoint(EntryBB); @@ -209,6 +265,8 @@ void CodeGenFunction::StartFunction(GlobalDecl GD, QualType RetTy, DI->EmitFunctionStart(GD, FnType, CurFn, Builder); } + EmitFunctionInstrumentation("__cyg_profile_func_enter"); + // FIXME: Leaked. // CC info is ignored, hopefully? CurFnInfo = &CGM.getTypes().getFunctionInfo(FnRetTy, Args, @@ -513,15 +571,11 @@ CodeGenFunction::EmitNullInitialization(llvm::Value *DestPtr, QualType Ty) { return; // FIXME: Handle variable sized types. - const llvm::Type *IntPtr = llvm::IntegerType::get(VMContext, - LLVMPointerWidth); - - Builder.CreateCall5(CGM.getMemSetFn(BP, IntPtr), DestPtr, + Builder.CreateCall5(CGM.getMemSetFn(BP, IntPtrTy), DestPtr, llvm::Constant::getNullValue(llvm::Type::getInt8Ty(VMContext)), // TypeInfo.first describes size in bits. - llvm::ConstantInt::get(IntPtr, TypeInfo.first/8), - llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), - TypeInfo.second/8), + llvm::ConstantInt::get(IntPtrTy, TypeInfo.first/8), + llvm::ConstantInt::get(Int32Ty, TypeInfo.second/8), llvm::ConstantInt::get(llvm::Type::getInt1Ty(VMContext), 0)); } @@ -531,7 +585,7 @@ llvm::BlockAddress *CodeGenFunction::GetAddrOfLabel(const LabelStmt *L) { if (IndirectBranch == 0) GetIndirectGotoBlock(); - llvm::BasicBlock *BB = getBasicBlockForLabel(L); + llvm::BasicBlock *BB = getJumpDestForLabel(L).Block; // Make sure the indirect branch includes all of the address-taken blocks. IndirectBranch->addDestination(BB); @@ -603,233 +657,574 @@ llvm::Value *CodeGenFunction::EmitVLASize(QualType Ty) { } llvm::Value* CodeGenFunction::EmitVAListRef(const Expr* E) { - if (CGM.getContext().getBuiltinVaListType()->isArrayType()) { + if (CGM.getContext().getBuiltinVaListType()->isArrayType()) return EmitScalarExpr(E); - } return EmitLValue(E).getAddress(); } -void CodeGenFunction::PushCleanupBlock(llvm::BasicBlock *CleanupEntryBlock, - llvm::BasicBlock *CleanupExitBlock, - llvm::BasicBlock *PreviousInvokeDest, - bool EHOnly) { - CleanupEntries.push_back(CleanupEntry(CleanupEntryBlock, CleanupExitBlock, - PreviousInvokeDest, EHOnly)); +/// Pops cleanup blocks until the given savepoint is reached. +void CodeGenFunction::PopCleanupBlocks(EHScopeStack::stable_iterator Old) { + assert(Old.isValid()); + + EHScopeStack::iterator E = EHStack.find(Old); + while (EHStack.begin() != E) + PopCleanupBlock(); +} + +/// Destroys a cleanup if it was unused. +static void DestroyCleanup(CodeGenFunction &CGF, + llvm::BasicBlock *Entry, + llvm::BasicBlock *Exit) { + assert(Entry->use_empty() && "destroying cleanup with uses!"); + assert(Exit->getTerminator() == 0 && + "exit has terminator but entry has no predecessors!"); + + // This doesn't always remove the entire cleanup, but it's much + // safer as long as we don't know what blocks belong to the cleanup. + // A *much* better approach if we care about this inefficiency would + // be to lazily emit the cleanup. + + // If the exit block is distinct from the entry, give it a branch to + // an unreachable destination. This preserves the well-formedness + // of the IR. + if (Entry != Exit) + llvm::BranchInst::Create(CGF.getUnreachableBlock(), Exit); + + assert(!Entry->getParent() && "cleanup entry already positioned?"); + // We can't just delete the entry; we have to kill any references to + // its instructions in other blocks. + for (llvm::BasicBlock::iterator I = Entry->begin(), E = Entry->end(); + I != E; ++I) + if (!I->use_empty()) + I->replaceAllUsesWith(llvm::UndefValue::get(I->getType())); + delete Entry; } -void CodeGenFunction::EmitCleanupBlocks(size_t OldCleanupStackSize) { - assert(CleanupEntries.size() >= OldCleanupStackSize && - "Cleanup stack mismatch!"); +/// Creates a switch instruction to thread branches out of the given +/// block (which is the exit block of a cleanup). +static void CreateCleanupSwitch(CodeGenFunction &CGF, + llvm::BasicBlock *Block) { + if (Block->getTerminator()) { + assert(isa<llvm::SwitchInst>(Block->getTerminator()) && + "cleanup block already has a terminator, but it isn't a switch"); + return; + } - while (CleanupEntries.size() > OldCleanupStackSize) - EmitCleanupBlock(); + llvm::Value *DestCodePtr + = CGF.CreateTempAlloca(CGF.Builder.getInt32Ty(), "cleanup.dst"); + CGBuilderTy Builder(Block); + llvm::Value *DestCode = Builder.CreateLoad(DestCodePtr, "tmp"); + + // Create a switch instruction to determine where to jump next. + Builder.CreateSwitch(DestCode, CGF.getUnreachableBlock()); } -CodeGenFunction::CleanupBlockInfo CodeGenFunction::PopCleanupBlock() { - CleanupEntry &CE = CleanupEntries.back(); +/// Attempts to reduce a cleanup's entry block to a fallthrough. This +/// is basically llvm::MergeBlockIntoPredecessor, except +/// simplified/optimized for the tighter constraints on cleanup +/// blocks. +static void SimplifyCleanupEntry(CodeGenFunction &CGF, + llvm::BasicBlock *Entry) { + llvm::BasicBlock *Pred = Entry->getSinglePredecessor(); + if (!Pred) return; - llvm::BasicBlock *CleanupEntryBlock = CE.CleanupEntryBlock; + llvm::BranchInst *Br = dyn_cast<llvm::BranchInst>(Pred->getTerminator()); + if (!Br || Br->isConditional()) return; + assert(Br->getSuccessor(0) == Entry); - std::vector<llvm::BasicBlock *> Blocks; - std::swap(Blocks, CE.Blocks); + // If we were previously inserting at the end of the cleanup entry + // block, we'll need to continue inserting at the end of the + // predecessor. + bool WasInsertBlock = CGF.Builder.GetInsertBlock() == Entry; + assert(!WasInsertBlock || CGF.Builder.GetInsertPoint() == Entry->end()); - std::vector<llvm::BranchInst *> BranchFixups; - std::swap(BranchFixups, CE.BranchFixups); + // Kill the branch. + Br->eraseFromParent(); - bool EHOnly = CE.EHOnly; + // Merge the blocks. + Pred->getInstList().splice(Pred->end(), Entry->getInstList()); - setInvokeDest(CE.PreviousInvokeDest); + // Kill the entry block. + Entry->eraseFromParent(); - CleanupEntries.pop_back(); + if (WasInsertBlock) + CGF.Builder.SetInsertPoint(Pred); +} - // Check if any branch fixups pointed to the scope we just popped. If so, - // we can remove them. - for (size_t i = 0, e = BranchFixups.size(); i != e; ++i) { - llvm::BasicBlock *Dest = BranchFixups[i]->getSuccessor(0); - BlockScopeMap::iterator I = BlockScopes.find(Dest); +/// Attempts to reduce an cleanup's exit switch to an unconditional +/// branch. +static void SimplifyCleanupExit(llvm::BasicBlock *Exit) { + llvm::TerminatorInst *Terminator = Exit->getTerminator(); + assert(Terminator && "completed cleanup exit has no terminator"); - if (I == BlockScopes.end()) - continue; + llvm::SwitchInst *Switch = dyn_cast<llvm::SwitchInst>(Terminator); + if (!Switch) return; + if (Switch->getNumCases() != 2) return; // default + 1 - assert(I->second <= CleanupEntries.size() && "Invalid branch fixup!"); + llvm::LoadInst *Cond = cast<llvm::LoadInst>(Switch->getCondition()); + llvm::AllocaInst *CondVar = cast<llvm::AllocaInst>(Cond->getPointerOperand()); - if (I->second == CleanupEntries.size()) { - // We don't need to do this branch fixup. - BranchFixups[i] = BranchFixups.back(); - BranchFixups.pop_back(); - i--; - e--; - continue; - } - } + // Replace the switch instruction with an unconditional branch. + llvm::BasicBlock *Dest = Switch->getSuccessor(1); // default is 0 + Switch->eraseFromParent(); + llvm::BranchInst::Create(Dest, Exit); - llvm::BasicBlock *SwitchBlock = CE.CleanupExitBlock; - llvm::BasicBlock *EndBlock = 0; - if (!BranchFixups.empty()) { - if (!SwitchBlock) - SwitchBlock = createBasicBlock("cleanup.switch"); - EndBlock = createBasicBlock("cleanup.end"); + // Delete all uses of the condition variable. + Cond->eraseFromParent(); + while (!CondVar->use_empty()) + cast<llvm::StoreInst>(*CondVar->use_begin())->eraseFromParent(); - llvm::BasicBlock *CurBB = Builder.GetInsertBlock(); + // Delete the condition variable itself. + CondVar->eraseFromParent(); +} - Builder.SetInsertPoint(SwitchBlock); +/// Threads a branch fixup through a cleanup block. +static void ThreadFixupThroughCleanup(CodeGenFunction &CGF, + BranchFixup &Fixup, + llvm::BasicBlock *Entry, + llvm::BasicBlock *Exit) { + if (!Exit->getTerminator()) + CreateCleanupSwitch(CGF, Exit); - llvm::Value *DestCodePtr - = CreateTempAlloca(llvm::Type::getInt32Ty(VMContext), - "cleanup.dst"); - llvm::Value *DestCode = Builder.CreateLoad(DestCodePtr, "tmp"); + // Find the switch and its destination index alloca. + llvm::SwitchInst *Switch = cast<llvm::SwitchInst>(Exit->getTerminator()); + llvm::Value *DestCodePtr = + cast<llvm::LoadInst>(Switch->getCondition())->getPointerOperand(); - // Create a switch instruction to determine where to jump next. - llvm::SwitchInst *SI = Builder.CreateSwitch(DestCode, EndBlock, - BranchFixups.size()); + // Compute the index of the new case we're adding to the switch. + unsigned Index = Switch->getNumCases(); - // Restore the current basic block (if any) - if (CurBB) { - Builder.SetInsertPoint(CurBB); + const llvm::IntegerType *i32 = llvm::Type::getInt32Ty(CGF.getLLVMContext()); + llvm::ConstantInt *IndexV = llvm::ConstantInt::get(i32, Index); - // If we had a current basic block, we also need to emit an instruction - // to initialize the cleanup destination. - Builder.CreateStore(llvm::Constant::getNullValue(llvm::Type::getInt32Ty(VMContext)), - DestCodePtr); - } else - Builder.ClearInsertionPoint(); - - for (size_t i = 0, e = BranchFixups.size(); i != e; ++i) { - llvm::BranchInst *BI = BranchFixups[i]; - llvm::BasicBlock *Dest = BI->getSuccessor(0); - - // Fixup the branch instruction to point to the cleanup block. - BI->setSuccessor(0, CleanupEntryBlock); - - if (CleanupEntries.empty()) { - llvm::ConstantInt *ID; - - // Check if we already have a destination for this block. - if (Dest == SI->getDefaultDest()) - ID = llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), 0); - else { - ID = SI->findCaseDest(Dest); - if (!ID) { - // No code found, get a new unique one by using the number of - // switch successors. - ID = llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), - SI->getNumSuccessors()); - SI->addCase(ID, Dest); - } - } + // Set the index in the origin block. + new llvm::StoreInst(IndexV, DestCodePtr, Fixup.Origin); - // Store the jump destination before the branch instruction. - new llvm::StoreInst(ID, DestCodePtr, BI); - } else { - // We need to jump through another cleanup block. Create a pad block - // with a branch instruction that jumps to the final destination and add - // it as a branch fixup to the current cleanup scope. + // Add a case to the switch. + Switch->addCase(IndexV, Fixup.Destination); - // Create the pad block. - llvm::BasicBlock *CleanupPad = createBasicBlock("cleanup.pad", CurFn); + // Change the last branch to point to the cleanup entry block. + Fixup.LatestBranch->setSuccessor(Fixup.LatestBranchIndex, Entry); - // Create a unique case ID. - llvm::ConstantInt *ID - = llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), - SI->getNumSuccessors()); + // And finally, update the fixup. + Fixup.LatestBranch = Switch; + Fixup.LatestBranchIndex = Index; +} - // Store the jump destination before the branch instruction. - new llvm::StoreInst(ID, DestCodePtr, BI); +/// Try to simplify both the entry and exit edges of a cleanup. +static void SimplifyCleanupEdges(CodeGenFunction &CGF, + llvm::BasicBlock *Entry, + llvm::BasicBlock *Exit) { - // Add it as the destination. - SI->addCase(ID, CleanupPad); + // Given their current implementations, it's important to run these + // in this order: SimplifyCleanupEntry will delete Entry if it can + // be merged into its predecessor, which will then break + // SimplifyCleanupExit if (as is common) Entry == Exit. - // Create the branch to the final destination. - llvm::BranchInst *BI = llvm::BranchInst::Create(Dest); - CleanupPad->getInstList().push_back(BI); + SimplifyCleanupExit(Exit); + SimplifyCleanupEntry(CGF, Entry); +} - // And add it as a branch fixup. - CleanupEntries.back().BranchFixups.push_back(BI); - } - } +static void EmitLazyCleanup(CodeGenFunction &CGF, + EHScopeStack::LazyCleanup *Fn, + bool ForEH) { + if (ForEH) CGF.EHStack.pushTerminate(); + Fn->Emit(CGF, ForEH); + if (ForEH) CGF.EHStack.popTerminate(); + assert(CGF.HaveInsertPoint() && "cleanup ended with no insertion point?"); +} + +static void SplitAndEmitLazyCleanup(CodeGenFunction &CGF, + EHScopeStack::LazyCleanup *Fn, + bool ForEH, + llvm::BasicBlock *Entry) { + assert(Entry && "no entry block for cleanup"); + + // Remove the switch and load from the end of the entry block. + llvm::Instruction *Switch = &Entry->getInstList().back(); + Entry->getInstList().remove(Switch); + assert(isa<llvm::SwitchInst>(Switch)); + llvm::Instruction *Load = &Entry->getInstList().back(); + Entry->getInstList().remove(Load); + assert(isa<llvm::LoadInst>(Load)); + + assert(Entry->getInstList().empty() && + "lazy cleanup block not empty after removing load/switch pair?"); + + // Emit the actual cleanup at the end of the entry block. + CGF.Builder.SetInsertPoint(Entry); + EmitLazyCleanup(CGF, Fn, ForEH); + + // Put the load and switch at the end of the exit block. + llvm::BasicBlock *Exit = CGF.Builder.GetInsertBlock(); + Exit->getInstList().push_back(Load); + Exit->getInstList().push_back(Switch); + + // Clean up the edges if possible. + SimplifyCleanupEdges(CGF, Entry, Exit); + + CGF.Builder.ClearInsertionPoint(); +} + +static void PopLazyCleanupBlock(CodeGenFunction &CGF) { + assert(isa<EHLazyCleanupScope>(*CGF.EHStack.begin()) && "top not a cleanup!"); + EHLazyCleanupScope &Scope = cast<EHLazyCleanupScope>(*CGF.EHStack.begin()); + assert(Scope.getFixupDepth() <= CGF.EHStack.getNumBranchFixups()); + + // Check whether we need an EH cleanup. This is only true if we've + // generated a lazy EH cleanup block. + llvm::BasicBlock *EHEntry = Scope.getEHBlock(); + bool RequiresEHCleanup = (EHEntry != 0); + + // Check the three conditions which might require a normal cleanup: + + // - whether there are branch fix-ups through this cleanup + unsigned FixupDepth = Scope.getFixupDepth(); + bool HasFixups = CGF.EHStack.getNumBranchFixups() != FixupDepth; + + // - whether control has already been threaded through this cleanup + llvm::BasicBlock *NormalEntry = Scope.getNormalBlock(); + bool HasExistingBranches = (NormalEntry != 0); + + // - whether there's a fallthrough + llvm::BasicBlock *FallthroughSource = CGF.Builder.GetInsertBlock(); + bool HasFallthrough = (FallthroughSource != 0); + + bool RequiresNormalCleanup = false; + if (Scope.isNormalCleanup() && + (HasFixups || HasExistingBranches || HasFallthrough)) { + RequiresNormalCleanup = true; } - // Remove all blocks from the block scope map. - for (size_t i = 0, e = Blocks.size(); i != e; ++i) { - assert(BlockScopes.count(Blocks[i]) && - "Did not find block in scope map!"); + // If we don't need the cleanup at all, we're done. + if (!RequiresNormalCleanup && !RequiresEHCleanup) { + CGF.EHStack.popCleanup(); + assert(CGF.EHStack.getNumBranchFixups() == 0 || + CGF.EHStack.hasNormalCleanups()); + return; + } + + // Copy the cleanup emission data out. Note that SmallVector + // guarantees maximal alignment for its buffer regardless of its + // type parameter. + llvm::SmallVector<char, 8*sizeof(void*)> CleanupBuffer; + CleanupBuffer.reserve(Scope.getCleanupSize()); + memcpy(CleanupBuffer.data(), + Scope.getCleanupBuffer(), Scope.getCleanupSize()); + CleanupBuffer.set_size(Scope.getCleanupSize()); + EHScopeStack::LazyCleanup *Fn = + reinterpret_cast<EHScopeStack::LazyCleanup*>(CleanupBuffer.data()); + + // We're done with the scope; pop it off so we can emit the cleanups. + CGF.EHStack.popCleanup(); + + if (RequiresNormalCleanup) { + // If we have a fallthrough and no other need for the cleanup, + // emit it directly. + if (HasFallthrough && !HasFixups && !HasExistingBranches) { + EmitLazyCleanup(CGF, Fn, /*ForEH*/ false); + + // Otherwise, the best approach is to thread everything through + // the cleanup block and then try to clean up after ourselves. + } else { + // Force the entry block to exist. + if (!HasExistingBranches) { + NormalEntry = CGF.createBasicBlock("cleanup"); + CreateCleanupSwitch(CGF, NormalEntry); + } - BlockScopes.erase(Blocks[i]); + CGF.EmitBlock(NormalEntry); + + // Thread the fallthrough edge through the (momentarily trivial) + // cleanup. + llvm::BasicBlock *FallthroughDestination = 0; + if (HasFallthrough) { + assert(isa<llvm::BranchInst>(FallthroughSource->getTerminator())); + FallthroughDestination = CGF.createBasicBlock("cleanup.cont"); + + BranchFixup Fix; + Fix.Destination = FallthroughDestination; + Fix.LatestBranch = FallthroughSource->getTerminator(); + Fix.LatestBranchIndex = 0; + Fix.Origin = Fix.LatestBranch; + + // Restore fixup invariant. EmitBlock added a branch to the + // cleanup which we need to redirect to the destination. + cast<llvm::BranchInst>(Fix.LatestBranch) + ->setSuccessor(0, Fix.Destination); + + ThreadFixupThroughCleanup(CGF, Fix, NormalEntry, NormalEntry); + } + + // Thread any "real" fixups we need to thread. + for (unsigned I = FixupDepth, E = CGF.EHStack.getNumBranchFixups(); + I != E; ++I) + if (CGF.EHStack.getBranchFixup(I).Destination) + ThreadFixupThroughCleanup(CGF, CGF.EHStack.getBranchFixup(I), + NormalEntry, NormalEntry); + + SplitAndEmitLazyCleanup(CGF, Fn, /*ForEH*/ false, NormalEntry); + + if (HasFallthrough) + CGF.EmitBlock(FallthroughDestination); + } } - return CleanupBlockInfo(CleanupEntryBlock, SwitchBlock, EndBlock, EHOnly); + // Emit the EH cleanup if required. + if (RequiresEHCleanup) { + CGBuilderTy::InsertPoint SavedIP = CGF.Builder.saveAndClearIP(); + CGF.EmitBlock(EHEntry); + SplitAndEmitLazyCleanup(CGF, Fn, /*ForEH*/ true, EHEntry); + CGF.Builder.restoreIP(SavedIP); + } } -void CodeGenFunction::EmitCleanupBlock() { - CleanupBlockInfo Info = PopCleanupBlock(); +/// Pops a cleanup block. If the block includes a normal cleanup, the +/// current insertion point is threaded through the cleanup, as are +/// any branch fixups on the cleanup. +void CodeGenFunction::PopCleanupBlock() { + assert(!EHStack.empty() && "cleanup stack is empty!"); + if (isa<EHLazyCleanupScope>(*EHStack.begin())) + return PopLazyCleanupBlock(*this); + + assert(isa<EHCleanupScope>(*EHStack.begin()) && "top not a cleanup!"); + EHCleanupScope &Scope = cast<EHCleanupScope>(*EHStack.begin()); + assert(Scope.getFixupDepth() <= EHStack.getNumBranchFixups()); + + // Handle the EH cleanup if (1) there is one and (2) it's different + // from the normal cleanup. + if (Scope.isEHCleanup() && + Scope.getEHEntry() != Scope.getNormalEntry()) { + llvm::BasicBlock *EHEntry = Scope.getEHEntry(); + llvm::BasicBlock *EHExit = Scope.getEHExit(); + + if (EHEntry->use_empty()) { + DestroyCleanup(*this, EHEntry, EHExit); + } else { + // TODO: this isn't really the ideal location to put this EH + // cleanup, but lazy emission is a better solution than trying + // to pick a better spot. + CGBuilderTy::InsertPoint SavedIP = Builder.saveAndClearIP(); + EmitBlock(EHEntry); + Builder.restoreIP(SavedIP); + + SimplifyCleanupEdges(*this, EHEntry, EHExit); + } + } + + // If we only have an EH cleanup, we don't really need to do much + // here. Branch fixups just naturally drop down to the enclosing + // cleanup scope. + if (!Scope.isNormalCleanup()) { + EHStack.popCleanup(); + assert(EHStack.getNumBranchFixups() == 0 || EHStack.hasNormalCleanups()); + return; + } - if (Info.EHOnly) { - // FIXME: Add this to the exceptional edge - if (Info.CleanupBlock->getNumUses() == 0) - delete Info.CleanupBlock; + // Check whether the scope has any fixups that need to be threaded. + unsigned FixupDepth = Scope.getFixupDepth(); + bool HasFixups = EHStack.getNumBranchFixups() != FixupDepth; + + // Grab the entry and exit blocks. + llvm::BasicBlock *Entry = Scope.getNormalEntry(); + llvm::BasicBlock *Exit = Scope.getNormalExit(); + + // Check whether anything's been threaded through the cleanup already. + assert((Exit->getTerminator() == 0) == Entry->use_empty() && + "cleanup entry/exit mismatch"); + bool HasExistingBranches = !Entry->use_empty(); + + // Check whether we need to emit a "fallthrough" branch through the + // cleanup for the current insertion point. + llvm::BasicBlock *FallThrough = Builder.GetInsertBlock(); + if (FallThrough && FallThrough->getTerminator()) + FallThrough = 0; + + // If *nothing* is using the cleanup, kill it. + if (!FallThrough && !HasFixups && !HasExistingBranches) { + EHStack.popCleanup(); + DestroyCleanup(*this, Entry, Exit); return; } - // Scrub debug location info. - for (llvm::BasicBlock::iterator LBI = Info.CleanupBlock->begin(), - LBE = Info.CleanupBlock->end(); LBI != LBE; ++LBI) - Builder.SetInstDebugLocation(LBI); + // Otherwise, add the block to the function. + EmitBlock(Entry); - llvm::BasicBlock *CurBB = Builder.GetInsertBlock(); - if (CurBB && !CurBB->getTerminator() && - Info.CleanupBlock->getNumUses() == 0) { - CurBB->getInstList().splice(CurBB->end(), Info.CleanupBlock->getInstList()); - delete Info.CleanupBlock; - } else - EmitBlock(Info.CleanupBlock); + if (FallThrough) + Builder.SetInsertPoint(Exit); + else + Builder.ClearInsertionPoint(); - if (Info.SwitchBlock) - EmitBlock(Info.SwitchBlock); - if (Info.EndBlock) - EmitBlock(Info.EndBlock); -} + // Fast case: if we don't have to add any fixups, and either + // we don't have a fallthrough or the cleanup wasn't previously + // used, then the setup above is sufficient. + if (!HasFixups) { + if (!FallThrough) { + assert(HasExistingBranches && "no reason for cleanup but didn't kill before"); + EHStack.popCleanup(); + SimplifyCleanupEdges(*this, Entry, Exit); + return; + } else if (!HasExistingBranches) { + assert(FallThrough && "no reason for cleanup but didn't kill before"); + // We can't simplify the exit edge in this case because we're + // already inserting at the end of the exit block. + EHStack.popCleanup(); + SimplifyCleanupEntry(*this, Entry); + return; + } + } + + // Otherwise we're going to have to thread things through the cleanup. + llvm::SmallVector<BranchFixup*, 8> Fixups; -void CodeGenFunction::AddBranchFixup(llvm::BranchInst *BI) { - assert(!CleanupEntries.empty() && - "Trying to add branch fixup without cleanup block!"); + // Synthesize a fixup for the current insertion point. + BranchFixup Cur; + if (FallThrough) { + Cur.Destination = createBasicBlock("cleanup.cont"); + Cur.LatestBranch = FallThrough->getTerminator(); + Cur.LatestBranchIndex = 0; + Cur.Origin = Cur.LatestBranch; - // FIXME: We could be more clever here and check if there's already a branch - // fixup for this destination and recycle it. - CleanupEntries.back().BranchFixups.push_back(BI); + // Restore fixup invariant. EmitBlock added a branch to the cleanup + // which we need to redirect to the destination. + cast<llvm::BranchInst>(Cur.LatestBranch)->setSuccessor(0, Cur.Destination); + + Fixups.push_back(&Cur); + } else { + Cur.Destination = 0; + } + + // Collect any "real" fixups we need to thread. + for (unsigned I = FixupDepth, E = EHStack.getNumBranchFixups(); + I != E; ++I) + if (EHStack.getBranchFixup(I).Destination) + Fixups.push_back(&EHStack.getBranchFixup(I)); + + assert(!Fixups.empty() && "no fixups, invariants broken!"); + + // If there's only a single fixup to thread through, do so with + // unconditional branches. This only happens if there's a single + // branch and no fallthrough. + if (Fixups.size() == 1 && !HasExistingBranches) { + Fixups[0]->LatestBranch->setSuccessor(Fixups[0]->LatestBranchIndex, Entry); + llvm::BranchInst *Br = + llvm::BranchInst::Create(Fixups[0]->Destination, Exit); + Fixups[0]->LatestBranch = Br; + Fixups[0]->LatestBranchIndex = 0; + + // Otherwise, force a switch statement and thread everything through + // the switch. + } else { + CreateCleanupSwitch(*this, Exit); + for (unsigned I = 0, E = Fixups.size(); I != E; ++I) + ThreadFixupThroughCleanup(*this, *Fixups[I], Entry, Exit); + } + + // Emit the fallthrough destination block if necessary. + if (Cur.Destination) + EmitBlock(Cur.Destination); + + // We're finally done with the cleanup. + EHStack.popCleanup(); } -void CodeGenFunction::EmitBranchThroughCleanup(llvm::BasicBlock *Dest) { +void CodeGenFunction::EmitBranchThroughCleanup(JumpDest Dest) { if (!HaveInsertPoint()) return; - llvm::BranchInst* BI = Builder.CreateBr(Dest); - - Builder.ClearInsertionPoint(); + // Create the branch. + llvm::BranchInst *BI = Builder.CreateBr(Dest.Block); - // The stack is empty, no need to do any cleanup. - if (CleanupEntries.empty()) + // If we're not in a cleanup scope, we don't need to worry about + // fixups. + if (!EHStack.hasNormalCleanups()) { + Builder.ClearInsertionPoint(); return; + } - if (!Dest->getParent()) { - // We are trying to branch to a block that hasn't been inserted yet. - AddBranchFixup(BI); + // Initialize a fixup. + BranchFixup Fixup; + Fixup.Destination = Dest.Block; + Fixup.Origin = BI; + Fixup.LatestBranch = BI; + Fixup.LatestBranchIndex = 0; + + // If we can't resolve the destination cleanup scope, just add this + // to the current cleanup scope. + if (!Dest.ScopeDepth.isValid()) { + EHStack.addBranchFixup() = Fixup; + Builder.ClearInsertionPoint(); return; } - BlockScopeMap::iterator I = BlockScopes.find(Dest); - if (I == BlockScopes.end()) { - // We are trying to jump to a block that is outside of any cleanup scope. - AddBranchFixup(BI); - return; + for (EHScopeStack::iterator I = EHStack.begin(), + E = EHStack.find(Dest.ScopeDepth); I != E; ++I) { + if (isa<EHCleanupScope>(*I)) { + EHCleanupScope &Scope = cast<EHCleanupScope>(*I); + if (Scope.isNormalCleanup()) + ThreadFixupThroughCleanup(*this, Fixup, Scope.getNormalEntry(), + Scope.getNormalExit()); + } else if (isa<EHLazyCleanupScope>(*I)) { + EHLazyCleanupScope &Scope = cast<EHLazyCleanupScope>(*I); + if (Scope.isNormalCleanup()) { + llvm::BasicBlock *Block = Scope.getNormalBlock(); + if (!Block) { + Block = createBasicBlock("cleanup"); + Scope.setNormalBlock(Block); + } + ThreadFixupThroughCleanup(*this, Fixup, Block, Block); + } + } } + + Builder.ClearInsertionPoint(); +} - assert(I->second < CleanupEntries.size() && - "Trying to branch into cleanup region"); +void CodeGenFunction::EmitBranchThroughEHCleanup(JumpDest Dest) { + if (!HaveInsertPoint()) + return; + + // Create the branch. + llvm::BranchInst *BI = Builder.CreateBr(Dest.Block); - if (I->second == CleanupEntries.size() - 1) { - // We have a branch to a block in the same scope. + // If we're not in a cleanup scope, we don't need to worry about + // fixups. + if (!EHStack.hasEHCleanups()) { + Builder.ClearInsertionPoint(); return; } - AddBranchFixup(BI); + // Initialize a fixup. + BranchFixup Fixup; + Fixup.Destination = Dest.Block; + Fixup.Origin = BI; + Fixup.LatestBranch = BI; + Fixup.LatestBranchIndex = 0; + + // We should never get invalid scope depths for these: invalid scope + // depths only arise for as-yet-unemitted labels, and we can't do an + // EH-unwind to one of those. + assert(Dest.ScopeDepth.isValid() && "invalid scope depth on EH dest?"); + + for (EHScopeStack::iterator I = EHStack.begin(), + E = EHStack.find(Dest.ScopeDepth); I != E; ++I) { + if (isa<EHCleanupScope>(*I)) { + EHCleanupScope &Scope = cast<EHCleanupScope>(*I); + if (Scope.isEHCleanup()) + ThreadFixupThroughCleanup(*this, Fixup, Scope.getEHEntry(), + Scope.getEHExit()); + } else if (isa<EHLazyCleanupScope>(*I)) { + EHLazyCleanupScope &Scope = cast<EHLazyCleanupScope>(*I); + if (Scope.isEHCleanup()) { + llvm::BasicBlock *Block = Scope.getEHBlock(); + if (!Block) { + Block = createBasicBlock("eh.cleanup"); + Scope.setEHBlock(Block); + } + ThreadFixupThroughCleanup(*this, Fixup, Block, Block); + } + } + } + + Builder.ClearInsertionPoint(); } |
