X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FVMCore%2FBasicBlock.cpp;h=f23a49696e479693c6f0f7326bd89e61cef1937d;hb=d04a8d4b33ff316ca4cf961e06c9e312eff8e64f;hp=64711fea0c7751861c084cb6f5dfff8e0fbc929b;hpb=0a4fd1ab7e7c83b3ecf03cbd6b35d2b164995267;p=oota-llvm.git diff --git a/lib/VMCore/BasicBlock.cpp b/lib/VMCore/BasicBlock.cpp index 64711fea0c7..f23a49696e4 100644 --- a/lib/VMCore/BasicBlock.cpp +++ b/lib/VMCore/BasicBlock.cpp @@ -12,70 +12,36 @@ //===----------------------------------------------------------------------===// #include "llvm/BasicBlock.h" +#include "SymbolTableListTraitsImpl.h" +#include "llvm/ADT/STLExtras.h" #include "llvm/Constants.h" #include "llvm/Instructions.h" -#include "llvm/Type.h" +#include "llvm/IntrinsicInst.h" +#include "llvm/LLVMContext.h" #include "llvm/Support/CFG.h" #include "llvm/Support/LeakDetector.h" -#include "llvm/Support/Compiler.h" -#include "SymbolTableListTraitsImpl.h" +#include "llvm/Type.h" #include using namespace llvm; -inline ValueSymbolTable * -ilist_traits::getSymTab(BasicBlock *BB) { - if (BB) - if (Function *F = BB->getParent()) - return &F->getValueSymbolTable(); +ValueSymbolTable *BasicBlock::getValueSymbolTable() { + if (Function *F = getParent()) + return &F->getValueSymbolTable(); return 0; } - -namespace { - /// DummyInst - An instance of this class is used to mark the end of the - /// instruction list. This is not a real instruction. - struct VISIBILITY_HIDDEN DummyInst : public Instruction { - // allocate space for exactly zero operands - void *operator new(size_t s) { - return User::operator new(s, 0); - } - DummyInst() : Instruction(Type::VoidTy, OtherOpsEnd, 0, 0) { - // This should not be garbage monitored. - LeakDetector::removeGarbageObject(this); - } - - Instruction *clone() const { - assert(0 && "Cannot clone EOL");abort(); - return 0; - } - const char *getOpcodeName() const { return "*end-of-list-inst*"; } - - // Methods for support type inquiry through isa, cast, and dyn_cast... - static inline bool classof(const DummyInst *) { return true; } - static inline bool classof(const Instruction *I) { - return I->getOpcode() == OtherOpsEnd; - } - static inline bool classof(const Value *V) { - return isa(V) && classof(cast(V)); - } - }; -} - -Instruction *ilist_traits::createSentinel() { - return new DummyInst(); -} -iplist &ilist_traits::getList(BasicBlock *BB) { - return BB->getInstList(); +LLVMContext &BasicBlock::getContext() const { + return getType()->getContext(); } // Explicit instantiation of SymbolTableListTraits since some of the methods // are not in the public header file... -template class SymbolTableListTraits; +template class llvm::SymbolTableListTraits; -BasicBlock::BasicBlock(const std::string &Name, Function *NewParent, +BasicBlock::BasicBlock(LLVMContext &C, const Twine &Name, Function *NewParent, BasicBlock *InsertBefore) - : Value(Type::LabelTy, Value::BasicBlockVal), Parent(0) { + : Value(Type::getLabelTy(C), Value::BasicBlockVal), Parent(0) { // Make sure that we get added to a function LeakDetector::addGarbageObject(this); @@ -87,12 +53,30 @@ BasicBlock::BasicBlock(const std::string &Name, Function *NewParent, } else if (NewParent) { NewParent->getBasicBlockList().push_back(this); } - + setName(Name); } BasicBlock::~BasicBlock() { + // If the address of the block is taken and it is being deleted (e.g. because + // it is dead), this means that there is either a dangling constant expr + // hanging off the block, or an undefined use of the block (source code + // expecting the address of a label to keep the block alive even though there + // is no indirect branch). Handle these cases by zapping the BlockAddress + // nodes. There are no other possible uses at this point. + if (hasAddressTaken()) { + assert(!use_empty() && "There should be at least one blockaddress!"); + Constant *Replacement = + ConstantInt::get(llvm::Type::getInt32Ty(getContext()), 1); + while (!use_empty()) { + BlockAddress *BA = cast(use_back()); + BA->replaceAllUsesWith(ConstantExpr::getIntToPtr(Replacement, + BA->getType())); + BA->destroyConstant(); + } + } + assert(getParent() == 0 && "BasicBlock still linked into the program!"); dropAllReferences(); InstList.clear(); @@ -153,6 +137,42 @@ Instruction* BasicBlock::getFirstNonPHI() { return &*i; } +Instruction* BasicBlock::getFirstNonPHIOrDbg() { + BasicBlock::iterator i = begin(); + // All valid basic blocks should have a terminator, + // which is not a PHINode. If we have an invalid basic + // block we'll get an assertion failure when dereferencing + // a past-the-end iterator. + while (isa(i) || isa(i)) ++i; + return &*i; +} + +Instruction* BasicBlock::getFirstNonPHIOrDbgOrLifetime() { + // All valid basic blocks should have a terminator, + // which is not a PHINode. If we have an invalid basic + // block we'll get an assertion failure when dereferencing + // a past-the-end iterator. + BasicBlock::iterator i = begin(); + for (;; ++i) { + if (isa(i) || isa(i)) + continue; + + const IntrinsicInst *II = dyn_cast(i); + if (!II) + break; + if (II->getIntrinsicID() != Intrinsic::lifetime_start && + II->getIntrinsicID() != Intrinsic::lifetime_end) + break; + } + return &*i; +} + +BasicBlock::iterator BasicBlock::getFirstInsertionPt() { + iterator InsertPt = getFirstNonPHI(); + if (isa(InsertPt)) ++InsertPt; + return InsertPt; +} + void BasicBlock::dropAllReferences() { for(iterator I = begin(), E = end(); I != E; ++I) I->dropAllReferences(); @@ -168,6 +188,25 @@ BasicBlock *BasicBlock::getSinglePredecessor() { return (PI == E) ? ThePred : 0 /*multiple preds*/; } +/// getUniquePredecessor - If this basic block has a unique predecessor block, +/// return the block, otherwise return a null pointer. +/// Note that unique predecessor doesn't mean single edge, there can be +/// multiple edges from the unique predecessor to this block (for example +/// a switch statement with multiple cases having the same destination). +BasicBlock *BasicBlock::getUniquePredecessor() { + pred_iterator PI = pred_begin(this), E = pred_end(this); + if (PI == E) return 0; // No preds. + BasicBlock *PredBB = *PI; + ++PI; + for (;PI != E; ++PI) { + if (*PI != PredBB) + return 0; + // The same predecessor appears multiple times in the predecessor list. + // This is OK. + } + return PredBB; +} + /// removePredecessor - This method is used to notify a BasicBlock that the /// specified Predecessor of the block is no longer able to reach it. This is /// actually not used to update the Predecessor list, but is actually used to @@ -214,8 +253,8 @@ void BasicBlock::removePredecessor(BasicBlock *Pred, // If the PHI _HAD_ two uses, replace PHI node with its now *single* value if (max_idx == 2) { - if (PN->getOperand(0) != PN) - PN->replaceAllUsesWith(PN->getOperand(0)); + if (PN->getIncomingValue(0) != PN) + PN->replaceAllUsesWith(PN->getIncomingValue(0)); else // We are left with an infinite loop with no entries: kill the PHI. PN->replaceAllUsesWith(UndefValue::get(PN->getType())); @@ -235,10 +274,11 @@ void BasicBlock::removePredecessor(BasicBlock *Pred, // If all incoming values to the Phi are the same, we can replace the Phi // with that value. Value* PNV = 0; - if (!DontDeleteUselessPHIs && (PNV = PN->hasConstantValue())) { - PN->replaceAllUsesWith(PNV); - PN->eraseFromParent(); - } + if (!DontDeleteUselessPHIs && (PNV = PN->hasConstantValue())) + if (PNV != PN) { + PN->replaceAllUsesWith(PNV); + PN->eraseFromParent(); + } } } } @@ -255,12 +295,15 @@ void BasicBlock::removePredecessor(BasicBlock *Pred, /// cause a degenerate basic block to be formed, having a terminator inside of /// the basic block). /// -BasicBlock *BasicBlock::splitBasicBlock(iterator I, const std::string &BBName) { +BasicBlock *BasicBlock::splitBasicBlock(iterator I, const Twine &BBName) { assert(getTerminator() && "Can't use splitBasicBlock on degenerate BB!"); assert(I != InstList.end() && "Trying to get me to create degenerate basic block!"); - BasicBlock *New = BasicBlock::Create(BBName, getParent(), getNext()); + BasicBlock *InsertBefore = llvm::next(Function::iterator(this)) + .getNodePtrUnchecked(); + BasicBlock *New = BasicBlock::Create(getContext(), BBName, + getParent(), InsertBefore); // Move all of the specified instructions from the original basic block into // the new basic block. @@ -290,3 +333,39 @@ BasicBlock *BasicBlock::splitBasicBlock(iterator I, const std::string &BBName) { } return New; } + +void BasicBlock::replaceSuccessorsPhiUsesWith(BasicBlock *New) { + TerminatorInst *TI = getTerminator(); + if (!TI) + // Cope with being called on a BasicBlock that doesn't have a terminator + // yet. Clang's CodeGenFunction::EmitReturnBlock() likes to do this. + return; + for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i) { + BasicBlock *Succ = TI->getSuccessor(i); + // N.B. Succ might not be a complete BasicBlock, so don't assume + // that it ends with a non-phi instruction. + for (iterator II = Succ->begin(), IE = Succ->end(); II != IE; ++II) { + PHINode *PN = dyn_cast(II); + if (!PN) + break; + int i; + while ((i = PN->getBasicBlockIndex(this)) >= 0) + PN->setIncomingBlock(i, New); + } + } +} + +/// isLandingPad - Return true if this basic block is a landing pad. I.e., it's +/// the destination of the 'unwind' edge of an invoke instruction. +bool BasicBlock::isLandingPad() const { + return isa(getFirstNonPHI()); +} + +/// getLandingPadInst() - Return the landingpad instruction associated with +/// the landing pad. +LandingPadInst *BasicBlock::getLandingPadInst() { + return dyn_cast(getFirstNonPHI()); +} +const LandingPadInst *BasicBlock::getLandingPadInst() const { + return dyn_cast(getFirstNonPHI()); +}