X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FVMCore%2FBasicBlock.cpp;h=3ab5e96157955b6bc60aa5077bb2918f84b3a231;hb=e6be34a53ecbe8c2ff9f0793b13d847e94c0de91;hp=32c86c4ce69079bd4be94e2067ddccb2cbba0ec5;hpb=551ccae044b0ff658fe629dd67edd5ffe75d10e8;p=oota-llvm.git diff --git a/lib/VMCore/BasicBlock.cpp b/lib/VMCore/BasicBlock.cpp index 32c86c4ce69..3ab5e961579 100644 --- a/lib/VMCore/BasicBlock.cpp +++ b/lib/VMCore/BasicBlock.cpp @@ -1,10 +1,10 @@ //===-- 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 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. @@ -12,30 +12,39 @@ //===----------------------------------------------------------------------===// #include "llvm/BasicBlock.h" -#include "llvm/Constant.h" +#include "llvm/Constants.h" #include "llvm/Instructions.h" #include "llvm/Type.h" #include "llvm/Support/CFG.h" -#include "llvm/SymbolTable.h" #include "llvm/Support/LeakDetector.h" +#include "llvm/Support/Compiler.h" #include "SymbolTableListTraitsImpl.h" #include using namespace llvm; +inline ValueSymbolTable * +ilist_traits::getSymTab(BasicBlock *BB) { + if (BB) + if (Function *F = BB->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 DummyInst : public Instruction { - DummyInst() : Instruction(Type::VoidTy, OtherOpsEnd) { + struct VISIBILITY_HIDDEN DummyInst : public Instruction { + DummyInst() : Instruction(Type::VoidTy, OtherOpsEnd, 0, 0) { // This should not be garbage monitored. LeakDetector::removeGarbageObject(this); } - virtual Instruction *clone() const { + Instruction *clone() const { assert(0 && "Cannot clone EOL");abort(); return 0; } - virtual const char *getOpcodeName() const { return "*end-of-list-inst*"; } + 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; } @@ -48,7 +57,7 @@ namespace { }; } -Instruction *ilist_traits::createNode() { +Instruction *ilist_traits::createSentinel() { return new DummyInst(); } iplist &ilist_traits::getList(BasicBlock *BB) { @@ -57,25 +66,25 @@ iplist &ilist_traits::getList(BasicBlock *BB) { // Explicit instantiation of SymbolTableListTraits since some of the methods // are not in the public header file... -template class SymbolTableListTraits; +template class SymbolTableListTraits; -BasicBlock::BasicBlock(const std::string &Name, Function *Parent, +BasicBlock::BasicBlock(const std::string &Name, Function *NewParent, BasicBlock *InsertBefore) - : Value(Type::LabelTy, Value::BasicBlockVal, Name) { - // Initialize the instlist... - InstList.setItemParent(this); + : Value(Type::LabelTy, Value::BasicBlockVal), Parent(0) { // Make sure that we get added to a function LeakDetector::addGarbageObject(this); if (InsertBefore) { - assert(Parent && + assert(NewParent && "Cannot insert block before another block with no function!"); - Parent->getBasicBlockList().insert(InsertBefore, this); - } else if (Parent) { - Parent->getBasicBlockList().push_back(this); + NewParent->getBasicBlockList().insert(InsertBefore, this); + } else if (NewParent) { + NewParent->getBasicBlockList().push_back(this); } + + setName(Name); } @@ -89,46 +98,86 @@ void BasicBlock::setParent(Function *parent) { if (getParent()) LeakDetector::addGarbageObject(this); - InstList.setParent(parent); + // Set Parent=parent, updating instruction symtab entries as appropriate. + InstList.setSymTabObject(&Parent, 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())) && - "Invalid symtab argument!"); - if ((P = getParent()) && hasName()) P->getSymbolTable().remove(this); - Value::setName(name); - if (P && hasName()) P->getSymbolTable().insert(this); +void BasicBlock::removeFromParent() { + getParent()->getBasicBlockList().remove(this); +} + +void BasicBlock::eraseFromParent() { + getParent()->getBasicBlockList().erase(this); +} + +/// moveBefore - Unlink this basic block from its current function and +/// insert it into the function that MovePos lives in, right before MovePos. +void BasicBlock::moveBefore(BasicBlock *MovePos) { + MovePos->getParent()->getBasicBlockList().splice(MovePos, + getParent()->getBasicBlockList(), this); } +/// moveAfter - Unlink this basic block from its current function and +/// insert it into the function that MovePos lives in, right after MovePos. +void BasicBlock::moveAfter(BasicBlock *MovePos) { + Function::iterator I = MovePos; + MovePos->getParent()->getBasicBlockList().splice(++I, + getParent()->getBasicBlockList(), this); +} + + TerminatorInst *BasicBlock::getTerminator() { if (InstList.empty()) return 0; return dyn_cast(&InstList.back()); } -const TerminatorInst *const BasicBlock::getTerminator() const { +const TerminatorInst *BasicBlock::getTerminator() const { if (InstList.empty()) return 0; return dyn_cast(&InstList.back()); } +Instruction* BasicBlock::getFirstNonPHI() +{ + BasicBlock::iterator i = begin(); + // All valid basic blocks should have a terminator, + // which is not a PHINode. If we have invalid basic + // block we'll get assert when dereferencing past-the-end + // iterator. + while (isa(i)) ++i; + return &*i; +} + void BasicBlock::dropAllReferences() { for(iterator I = begin(), E = end(); I != E; ++I) I->dropAllReferences(); } -// 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 -// update the PHI nodes that reside in the block. Note that this should be -// called while the predecessor still refers to this block. -// -void BasicBlock::removePredecessor(BasicBlock *Pred) { - assert(find(pred_begin(this), pred_end(this), Pred) != pred_end(this) && - "removePredecessor: BB is not a predecessor!"); +/// getSinglePredecessor - If this basic block has a single predecessor block, +/// return the block, otherwise return a null pointer. +BasicBlock *BasicBlock::getSinglePredecessor() { + pred_iterator PI = pred_begin(this), E = pred_end(this); + if (PI == E) return 0; // No preds. + BasicBlock *ThePred = *PI; + ++PI; + return (PI == E) ? ThePred : 0 /*multiple preds*/; +} + +/// 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 +/// update the PHI nodes that reside in the block. Note that this should be +/// called while the predecessor still refers to this block. +/// +void BasicBlock::removePredecessor(BasicBlock *Pred, + bool DontDeleteUselessPHIs) { + assert((hasNUsesOrMore(16)||// Reduce cost of this assertion for complex CFGs. + find(pred_begin(this), pred_end(this), Pred) != pred_end(this)) && + "removePredecessor: BB is not a predecessor!"); + + if (InstList.empty()) return; PHINode *APN = dyn_cast(&front()); if (!APN) return; // Quick exit. @@ -141,9 +190,9 @@ void BasicBlock::removePredecessor(BasicBlock *Pred) { // br Loop ;; %x2 does not dominate all uses // // This is because the PHI node input is actually taken from the predecessor - // basic block. The only case this can happen is with a self loop, so we + // 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) { @@ -153,10 +202,12 @@ void BasicBlock::removePredecessor(BasicBlock *Pred) { if (this == Other) max_idx = 3; } - if (max_idx <= 2) { // <= Two predecessors BEFORE I remove one? + // <= Two predecessors BEFORE I remove one? + if (max_idx <= 2 && !DontDeleteUselessPHIs) { // Yup, loop through and nuke the PHI nodes while (PHINode *PN = dyn_cast(&front())) { - PN->removeIncomingValue(Pred); // Remove the predecessor first... + // Remove the predecessor first. + PN->removeIncomingValue(Pred, !DontDeleteUselessPHIs); // If the PHI _HAD_ two uses, replace PHI node with its now *single* value if (max_idx == 2) { @@ -164,7 +215,7 @@ void BasicBlock::removePredecessor(BasicBlock *Pred) { 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())); + PN->replaceAllUsesWith(UndefValue::get(PN->getType())); getInstList().pop_front(); // Remove the PHI node } @@ -175,27 +226,36 @@ void BasicBlock::removePredecessor(BasicBlock *Pred) { // Okay, now we know that we need to remove predecessor #pred_idx from all // PHI nodes. Iterate over each PHI node fixing them up PHINode *PN; - for (iterator II = begin(); (PN = dyn_cast(II)); ++II) - PN->removeIncomingValue(Pred); + for (iterator II = begin(); (PN = dyn_cast(II)); ) { + ++II; + PN->removeIncomingValue(Pred, false); + // 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(); + } + } } } -// splitBasicBlock - This splits a basic block into two at the specified -// instruction. Note that all instructions BEFORE the specified iterator stay -// as part of the original basic block, an unconditional branch is added to -// the new BB, and the rest of the instructions in the BB are moved to the new -// BB, including the old terminator. This invalidates the iterator. -// -// Note that this only works on well formed basic blocks (must have a -// terminator), and 'I' must not be the end of instruction list (which would -// cause a degenerate basic block to be formed, having a terminator inside of -// the basic block). -// +/// splitBasicBlock - This splits a basic block into two at the specified +/// instruction. Note that all instructions BEFORE the specified iterator stay +/// as part of the original basic block, an unconditional branch is added to +/// the new BB, and the rest of the instructions in the BB are moved to the new +/// BB, including the old terminator. This invalidates the iterator. +/// +/// Note that this only works on well formed basic blocks (must have a +/// terminator), and 'I' must not be the end of instruction list (which would +/// 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) { assert(getTerminator() && "Can't use splitBasicBlock on degenerate BB!"); - assert(I != InstList.end() && - "Trying to get me to create degenerate basic block!"); + assert(I != InstList.end() && + "Trying to get me to create degenerate basic block!"); BasicBlock *New = new BasicBlock(BBName, getParent(), getNext());