X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FVMCore%2FBasicBlock.cpp;h=2e3b426e2b2e882b78e56ca6d4815380b8847c4e;hb=dec628eead87b20773c98a00830580df211acc98;hp=95eab23edff4b07e74cb341bcfb00e6512564f95;hpb=3464547968b58dda0acbf6e0e192f03f66652848;p=oota-llvm.git diff --git a/lib/VMCore/BasicBlock.cpp b/lib/VMCore/BasicBlock.cpp index 95eab23edff..2e3b426e2b2 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 implements the BasicBlock class for the VMCore library. @@ -17,6 +17,7 @@ #include "llvm/Type.h" #include "llvm/Support/CFG.h" #include "llvm/Support/LeakDetector.h" +#include "llvm/Support/Compiler.h" #include "SymbolTableListTraitsImpl.h" #include using namespace llvm; @@ -24,7 +25,7 @@ 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 { + struct VISIBILITY_HIDDEN DummyInst : public Instruction { DummyInst() : Instruction(Type::VoidTy, OtherOpsEnd, 0, 0) { // This should not be garbage monitored. LeakDetector::removeGarbageObject(this); @@ -61,7 +62,7 @@ template class SymbolTableListTraits; BasicBlock::BasicBlock(const std::string &Name, Function *Parent, BasicBlock *InsertBefore) - : Value(Type::LabelTy, Value::BasicBlockVal, Name) { + : Value(Type::LabelTy, Value::BasicBlockVal) { // Initialize the instlist... InstList.setItemParent(this); @@ -75,6 +76,8 @@ BasicBlock::BasicBlock(const std::string &Name, Function *Parent, } else if (Parent) { Parent->getBasicBlockList().push_back(this); } + + setName(Name); } @@ -102,6 +105,21 @@ 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; @@ -113,6 +131,17 @@ const TerminatorInst *const BasicBlock::getTerminator() const { 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(); @@ -128,17 +157,17 @@ BasicBlock *BasicBlock::getSinglePredecessor() { 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. -// +/// 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!"); + "removePredecessor: BB is not a predecessor!"); if (InstList.empty()) return; PHINode *APN = dyn_cast(&front()); @@ -153,9 +182,9 @@ 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) { @@ -189,27 +218,36 @@ 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) + 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());