X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FVMCore%2FBasicBlock.cpp;h=32c86c4ce69079bd4be94e2067ddccb2cbba0ec5;hb=e59eaf407a675845e278c2769e3dbed9f1daae8c;hp=446af17be1847fba4a313e34094bac5849f4d271;hpb=08272fbdb2dd227346789d9d9c4243dffe1ea3a6;p=oota-llvm.git diff --git a/lib/VMCore/BasicBlock.cpp b/lib/VMCore/BasicBlock.cpp index 446af17be18..32c86c4ce69 100644 --- a/lib/VMCore/BasicBlock.cpp +++ b/lib/VMCore/BasicBlock.cpp @@ -1,37 +1,52 @@ -//===-- BasicBlock.cpp - Implement BasicBlock related functions --*- C++ -*--=// +//===-- BasicBlock.cpp - Implement BasicBlock related methods -------------===// +// +// The LLVM Compiler Infrastructure +// +// This file was developed by the LLVM research group and is distributed under +// the University of Illinois Open Source License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// // // This file implements the BasicBlock class for the VMCore library. // //===----------------------------------------------------------------------===// #include "llvm/BasicBlock.h" -#include "llvm/iTerminators.h" +#include "llvm/Constant.h" +#include "llvm/Instructions.h" #include "llvm/Type.h" #include "llvm/Support/CFG.h" -#include "llvm/Constant.h" -#include "llvm/iPHINode.h" #include "llvm/SymbolTable.h" +#include "llvm/Support/LeakDetector.h" #include "SymbolTableListTraitsImpl.h" #include +using namespace llvm; + +namespace { + /// DummyInst - An instance of this class is used to mark the end of the + /// instruction list. This is not a real instruction. + struct DummyInst : public Instruction { + DummyInst() : Instruction(Type::VoidTy, OtherOpsEnd) { + // This should not be garbage monitored. + LeakDetector::removeGarbageObject(this); + } -// DummyInst - An instance of this class is used to mark the end of the -// instruction list. This is not a real instruction. -// -struct DummyInst : public Instruction { - DummyInst() : Instruction(Type::VoidTy, NumOtherOps) {} - - virtual Instruction *clone() const { assert(0 && "Cannot clone EOL");abort();} - virtual const char *getOpcodeName() const { return "*end-of-list-inst*"; } + virtual Instruction *clone() const { + assert(0 && "Cannot clone EOL");abort(); + return 0; + } + virtual 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() == NumOtherOps; - } - static inline bool classof(const Value *V) { - return isa(V) && classof(cast(V)); - } -}; + // 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::createNode() { return new DummyInst(); @@ -42,31 +57,52 @@ iplist &ilist_traits::getList(BasicBlock *BB) { // Explicit instantiation of SymbolTableListTraits since some of the methods // are not in the public header file... -template SymbolTableListTraits; +template class SymbolTableListTraits; -BasicBlock::BasicBlock(const std::string &name, Function *Parent) - : Value(Type::LabelTy, Value::BasicBlockVal, name) { +BasicBlock::BasicBlock(const std::string &Name, Function *Parent, + BasicBlock *InsertBefore) + : Value(Type::LabelTy, Value::BasicBlockVal, Name) { // Initialize the instlist... InstList.setItemParent(this); - if (Parent) + // Make sure that we get added to a function + LeakDetector::addGarbageObject(this); + + if (InsertBefore) { + assert(Parent && + "Cannot insert block before another block with no function!"); + Parent->getBasicBlockList().insert(InsertBefore, this); + } else if (Parent) { Parent->getBasicBlockList().push_back(this); + } } + BasicBlock::~BasicBlock() { + assert(getParent() == 0 && "BasicBlock still linked into the program!"); dropAllReferences(); InstList.clear(); } +void BasicBlock::setParent(Function *parent) { + if (getParent()) + LeakDetector::addGarbageObject(this); + + InstList.setParent(parent); + + if (getParent()) + LeakDetector::removeGarbageObject(this); +} + // Specialize setName to take care of symbol table majik void BasicBlock::setName(const std::string &name, SymbolTable *ST) { Function *P; - assert((ST == 0 || (!getParent() || ST == getParent()->getSymbolTable())) && + assert((ST == 0 || (!getParent() || ST == &getParent()->getSymbolTable())) && "Invalid symtab argument!"); - if ((P = getParent()) && hasName()) P->getSymbolTable()->remove(this); + if ((P = getParent()) && hasName()) P->getSymbolTable().remove(this); Value::setName(name); - if (P && hasName()) P->getSymbolTable()->insert(this); + if (P && hasName()) P->getSymbolTable().insert(this); } TerminatorInst *BasicBlock::getTerminator() { @@ -84,19 +120,6 @@ void BasicBlock::dropAllReferences() { I->dropAllReferences(); } -// hasConstantReferences() - This predicate is true if there is a -// reference to this basic block in the constant pool for this method. For -// example, if a block is reached through a switch table, that table resides -// in the constant pool, and the basic block is reference from it. -// -bool BasicBlock::hasConstantReferences() const { - for (use_const_iterator I = use_begin(), E = use_end(); I != E; ++I) - if (::isa((Value*)*I)) - return true; - - return false; -} - // 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 @@ -106,17 +129,11 @@ bool BasicBlock::hasConstantReferences() const { void BasicBlock::removePredecessor(BasicBlock *Pred) { assert(find(pred_begin(this), pred_end(this), Pred) != pred_end(this) && "removePredecessor: BB is not a predecessor!"); - if (!isa(front())) return; // Quick exit. - - pred_iterator PI(pred_begin(this)), EI(pred_end(this)); - unsigned max_idx; - - // Loop over the rest of the predecessors until we run out, or until we find - // out that there are more than 2 predecessors. - for (max_idx = 0; PI != EI && max_idx < 3; ++PI, ++max_idx) /*empty*/; + PHINode *APN = dyn_cast(&front()); + if (!APN) return; // Quick exit. // If there are exactly two predecessors, then we want to nuke the PHI nodes - // altogether. We cannot do this, however if this in this case however: + // altogether. However, we cannot do this, if this in this case: // // Loop: // %x = phi [X, Loop] @@ -127,10 +144,10 @@ void BasicBlock::removePredecessor(BasicBlock *Pred) { // basic block. The only case this can happen is with a self loop, so we // check for this case explicitly now. // + unsigned max_idx = APN->getNumIncomingValues(); assert(max_idx != 0 && "PHI Node in block with 0 predecessors!?!?!"); if (max_idx == 2) { - PI = pred_begin(this); - BasicBlock *Other = *PI == Pred ? *++PI : *PI; + BasicBlock *Other = APN->getIncomingBlock(APN->getIncomingBlock(0) == Pred); // Disable PHI elimination! if (this == Other) max_idx = 3; @@ -140,21 +157,25 @@ void BasicBlock::removePredecessor(BasicBlock *Pred) { // Yup, loop through and nuke the PHI nodes while (PHINode *PN = dyn_cast(&front())) { PN->removeIncomingValue(Pred); // Remove the predecessor first... - - assert(PN->getNumIncomingValues() == max_idx-1 && - "PHI node shouldn't have this many values!!!"); // If the PHI _HAD_ two uses, replace PHI node with its now *single* value - if (max_idx == 2) - PN->replaceAllUsesWith(PN->getOperand(0)); - else // Otherwise there are no incoming values/edges, replace with dummy - PN->replaceAllUsesWith(Constant::getNullValue(PN->getType())); - getInstList().pop_front(); // Remove the PHI node + if (max_idx == 2) { + if (PN->getOperand(0) != PN) + PN->replaceAllUsesWith(PN->getOperand(0)); + else + // We are left with an infinite loop with no entries: kill the PHI. + PN->replaceAllUsesWith(Constant::getNullValue(PN->getType())); + getInstList().pop_front(); // Remove the PHI node + } + + // If the PHI node already only had one entry, it got deleted by + // removeIncomingValue. } } else { // Okay, now we know that we need to remove predecessor #pred_idx from all // PHI nodes. Iterate over each PHI node fixing them up - for (iterator II = begin(); PHINode *PN = dyn_cast(&*II); ++II) + PHINode *PN; + for (iterator II = begin(); (PN = dyn_cast(II)); ++II) PN->removeIncomingValue(Pred); } } @@ -171,37 +192,32 @@ 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) { +BasicBlock *BasicBlock::splitBasicBlock(iterator I, const std::string &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 = new BasicBlock("", getParent()); + BasicBlock *New = new BasicBlock(BBName, getParent(), getNext()); - // Go from the end of the basic block through to the iterator pointer, moving - // to the new basic block... - Instruction *Inst = 0; - do { - iterator EndIt = end(); - Inst = InstList.remove(--EndIt); // Remove from end - New->InstList.push_front(Inst); // Add to front - } while (Inst != &*I); // Loop until we move the specified instruction. + // Move all of the specified instructions from the original basic block into + // the new basic block. + New->getInstList().splice(New->end(), this->getInstList(), I, end()); // Add a branch instruction to the newly formed basic block. - InstList.push_back(new BranchInst(New)); + new BranchInst(New, this); // Now we must loop through all of the successors of the New block (which // _were_ the successors of the 'this' block), and update any PHI nodes in // successors. If there were PHI nodes in the successors, then they need to // know that incoming branches will be from New, not from Old. // - for (BasicBlock::succ_iterator I = succ_begin(New), E = succ_end(New); - I != E; ++I) { + for (succ_iterator I = succ_begin(New), E = succ_end(New); I != E; ++I) { // Loop over any phi nodes in the basic block, updating the BB field of // incoming values... BasicBlock *Successor = *I; + PHINode *PN; for (BasicBlock::iterator II = Successor->begin(); - PHINode *PN = dyn_cast(&*II); ++II) { + (PN = dyn_cast(II)); ++II) { int IDX = PN->getBasicBlockIndex(this); while (IDX != -1) { PN->setIncomingBlock((unsigned)IDX, New);