X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FVMCore%2FBasicBlock.cpp;h=bf7191c659328fa5435731abd9cf756c277f0e4a;hb=1a143aef993a95e1caef2c8196d0b2f3f5f52c63;hp=df999b84bffd3072e7182042e476c89c57a0a008;hpb=697954c15da58bd8b186dbafdedd8b06db770201;p=oota-llvm.git diff --git a/lib/VMCore/BasicBlock.cpp b/lib/VMCore/BasicBlock.cpp index df999b84bff..bf7191c6593 100644 --- a/lib/VMCore/BasicBlock.cpp +++ b/lib/VMCore/BasicBlock.cpp @@ -1,39 +1,90 @@ -//===-- BasicBlock.cpp - Implement BasicBlock related functions --*- C++ -*--=// +//===-- BasicBlock.cpp - Implement BasicBlock related methods -------------===// // -// This file implements the Method class for the VMCore library. +// This file implements the BasicBlock class for the VMCore library. // //===----------------------------------------------------------------------===// -#include "llvm/ValueHolderImpl.h" #include "llvm/BasicBlock.h" #include "llvm/iTerminators.h" -#include "llvm/Method.h" -#include "llvm/SymbolTable.h" #include "llvm/Type.h" +#include "llvm/Support/CFG.h" +#include "llvm/Constant.h" #include "llvm/iPHINode.h" -#include "llvm/CodeGen/MachineInstr.h" +#include "llvm/SymbolTable.h" +#include "Support/LeakDetector.h" +#include "SymbolTableListTraitsImpl.h" +#include + +// 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) { + // This should not be garbage monitored. + LeakDetector::removeGarbageObject(this); + } + + 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)); + } +}; + +Instruction *ilist_traits::createNode() { + return new DummyInst(); +} +iplist &ilist_traits::getList(BasicBlock *BB) { + return BB->getInstList(); +} + +// Explicit instantiation of SymbolTableListTraits since some of the methods +// are not in the public header file... +template SymbolTableListTraits; -// Instantiate Templates - This ugliness is the price we have to pay -// for having a ValueHolderImpl.h file seperate from ValueHolder.h! :( + +// BasicBlock ctor - If the function parameter is specified, the basic block is +// automatically inserted at the end of the function. // -template class ValueHolder; +BasicBlock::BasicBlock(const std::string &name, Function *Parent) + : Value(Type::LabelTy, Value::BasicBlockVal, name) { + // Initialize the instlist... + InstList.setItemParent(this); + + // Make sure that we get added to a function + LeakDetector::addGarbageObject(this); -BasicBlock::BasicBlock(const std::string &name, Method *Parent) - : Value(Type::LabelTy, Value::BasicBlockVal, name), InstList(this, 0), - machineInstrVec(new MachineCodeForBasicBlock) { if (Parent) - Parent->getBasicBlocks().push_back(this); + Parent->getBasicBlockList().push_back(this); } BasicBlock::~BasicBlock() { dropAllReferences(); - InstList.delete_all(); - delete machineInstrVec; + 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) { - Method *P; + Function *P; assert((ST == 0 || (!getParent() || ST == getParent()->getSymbolTable())) && "Invalid symtab argument!"); if ((P = getParent()) && hasName()) P->getSymbolTable()->remove(this); @@ -41,33 +92,19 @@ void BasicBlock::setName(const std::string &name, SymbolTable *ST) { if (P && hasName()) P->getSymbolTable()->insert(this); } -void BasicBlock::setParent(Method *parent) { - if (getParent() && hasName()) - getParent()->getSymbolTable()->remove(this); - - InstList.setParent(parent); - - if (getParent() && hasName()) - getParent()->getSymbolTableSure()->insert(this); -} - TerminatorInst *BasicBlock::getTerminator() { if (InstList.empty()) return 0; - Instruction *T = InstList.back(); - if (isa(T)) return cast(T); - return 0; + return dyn_cast(&InstList.back()); } const TerminatorInst *const BasicBlock::getTerminator() const { if (InstList.empty()) return 0; - if (const TerminatorInst *TI = dyn_cast(InstList.back())) - return TI; - return 0; + return dyn_cast(&InstList.back()); } void BasicBlock::dropAllReferences() { - for_each(InstList.begin(), InstList.end(), - std::mem_fun(&Instruction::dropAllReferences)); + for(iterator I = begin(), E = end(); I != E; ++I) + I->dropAllReferences(); } // hasConstantReferences() - This predicate is true if there is a @@ -77,7 +114,7 @@ void BasicBlock::dropAllReferences() { // bool BasicBlock::hasConstantReferences() const { for (use_const_iterator I = use_begin(), E = use_end(); I != E; ++I) - if (::isa(*I)) + if (::isa((Value*)*I)) return true; return false; @@ -90,11 +127,11 @@ bool BasicBlock::hasConstantReferences() const { // called while the predecessor still refers to this block. // void BasicBlock::removePredecessor(BasicBlock *Pred) { - assert(find(pred_begin(), pred_end(), Pred) != pred_end() && + 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()), EI(pred_end()); + 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 @@ -102,11 +139,29 @@ void BasicBlock::removePredecessor(BasicBlock *Pred) { for (max_idx = 0; PI != EI && max_idx < 3; ++PI, ++max_idx) /*empty*/; // If there are exactly two predecessors, then we want to nuke the PHI nodes - // altogether. + // altogether. We cannot do this, however if this in this case however: + // + // Loop: + // %x = phi [X, Loop] + // %x2 = add %x, 1 ;; This would become %x2 = add %x2, 1 + // 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 + // check for this case explicitly now. + // 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; + + // Disable PHI elimination! + if (this == Other) max_idx = 3; + } + if (max_idx <= 2) { // <= Two predecessors BEFORE I remove one? // Yup, loop through and nuke the PHI nodes - while (PHINode *PN = dyn_cast(front())) { + while (PHINode *PN = dyn_cast(&front())) { PN->removeIncomingValue(Pred); // Remove the predecessor first... assert(PN->getNumIncomingValues() == max_idx-1 && @@ -115,14 +170,15 @@ void BasicBlock::removePredecessor(BasicBlock *Pred) { // If the PHI _HAD_ two uses, replace PHI node with its now *single* value if (max_idx == 2) PN->replaceAllUsesWith(PN->getOperand(0)); - delete getInstList().remove(begin()); // Remove the PHI node + else // Otherwise there are no incoming values/edges, replace with dummy + PN->replaceAllUsesWith(Constant::getNullValue(PN->getType())); + getInstList().pop_front(); // Remove the PHI node } } 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 - iterator II(begin()); - for (; isa(*II); ++II) - cast(*II)->removeIncomingValue(Pred); + for (iterator II = begin(); PHINode *PN = dyn_cast(&*II); ++II) + PN->removeIncomingValue(Pred); } } @@ -152,9 +208,29 @@ BasicBlock *BasicBlock::splitBasicBlock(iterator I) { 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. + } while (Inst != &*I); // Loop until we move the specified instruction. // Add a branch instruction to the newly formed basic block. InstList.push_back(new BranchInst(New)); + + // 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) { + // Loop over any phi nodes in the basic block, updating the BB field of + // incoming values... + BasicBlock *Successor = *I; + for (BasicBlock::iterator II = Successor->begin(); + PHINode *PN = dyn_cast(&*II); ++II) { + int IDX = PN->getBasicBlockIndex(this); + while (IDX != -1) { + PN->setIncomingBlock((unsigned)IDX, New); + IDX = PN->getBasicBlockIndex(this); + } + } + } return New; }