-//===-- 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 <algorithm>
+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<Instruction>(V) && classof(cast<Instruction>(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<Instruction>(V) && classof(cast<Instruction>(V));
+ }
+ };
+}
Instruction *ilist_traits<Instruction>::createNode() {
return new DummyInst();
// Explicit instantiation of SymbolTableListTraits since some of the methods
// are not in the public header file...
-template SymbolTableListTraits<Instruction, BasicBlock, Function>;
+template class SymbolTableListTraits<Instruction, BasicBlock, Function>;
-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() {
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<Constant>((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
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<PHINode>(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<PHINode>(&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]
// 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;
// Yup, loop through and nuke the PHI nodes
while (PHINode *PN = dyn_cast<PHINode>(&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<PHINode>(&*II); ++II)
+ PHINode *PN;
+ for (iterator II = begin(); (PN = dyn_cast<PHINode>(II)); ++II)
PN->removeIncomingValue(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<PHINode>(&*II); ++II) {
+ (PN = dyn_cast<PHINode>(II)); ++II) {
int IDX = PN->getBasicBlockIndex(this);
while (IDX != -1) {
PN->setIncomingBlock((unsigned)IDX, New);