static BasicBlock *findPredecessorBlock(const CompilationUnit *cUnit,
const BasicBlock *bb)
{
int numPred = dvmCountSetBits(bb->predecessors);
BitVectorIterator bvIterator;
dvmBitVectorIteratorInit(bb->predecessors, &bvIterator);
if (numPred == 1) {
int predIdx = dvmBitVectorIteratorNext(&bvIterator);
return (BasicBlock *) dvmGrowableListGetElement(&cUnit->blockList,
predIdx);
/* First loop block */
} else if ((numPred == 2) &&
dvmIsBitSet(bb->predecessors, cUnit->entryBlock->id)) {
while (true) {
int predIdx = dvmBitVectorIteratorNext(&bvIterator);
if (predIdx == cUnit->entryBlock->id) continue;
return (BasicBlock *) dvmGrowableListGetElement(&cUnit->blockList,
predIdx);
}
/* Doesn't support other shape of control flow yet */
} else {
return NULL;
}
}
/*
* Worker function to insert phi-operands with latest SSA names from
* predecessor blocks
*/
static bool insertPhiNodeOperands(CompilationUnit *cUnit, BasicBlock *bb) {
BitVector *ssaRegV = cUnit->tempSSARegisterV;
BitVectorIterator bvIterator;
GrowableList *blockList = &cUnit->blockList;
MIR *mir;
/* Phi nodes are at the beginning of each block */
for (mir = bb->firstMIRInsn; mir; mir = mir->next) {
if (mir->dalvikInsn.opcode != (Opcode) kMirOpPhi)
return true;
int ssaReg = mir->ssaRep->defs[0];
int encodedDalvikValue =
(int) dvmGrowableListGetElement(cUnit->ssaToDalvikMap, ssaReg);
int dalvikReg = DECODE_REG(encodedDalvikValue);
dvmClearAllBits(ssaRegV);
/* Iterate through the predecessors */
dvmBitVectorIteratorInit(bb->predecessors, &bvIterator);
while (true) {
int predIdx = dvmBitVectorIteratorNext(&bvIterator);
if (predIdx == -1) break;
BasicBlock *predBB = (BasicBlock *) dvmGrowableListGetElement(
blockList, predIdx);
int encodedSSAValue =
predBB->dataFlowInfo->dalvikToSSAMap[dalvikReg];
int ssaReg = DECODE_REG(encodedSSAValue);
dvmSetBit(ssaRegV, ssaReg);
}
/* Count the number of SSA registers for a Dalvik register */
int numUses = dvmCountSetBits(ssaRegV);
mir->ssaRep->numUses = numUses;
mir->ssaRep->uses =
(int *) dvmCompilerNew(sizeof(int) * numUses, false);
mir->ssaRep->fpUse =
(bool *) dvmCompilerNew(sizeof(bool) * numUses, true);
BitVectorIterator phiIterator;
dvmBitVectorIteratorInit(ssaRegV, &phiIterator);
int *usePtr = mir->ssaRep->uses;
/* Set the uses array for the phi node */
while (true) {
int ssaRegIdx = dvmBitVectorIteratorNext(&phiIterator);
if (ssaRegIdx == -1) break;
*usePtr++ = ssaRegIdx;
}
}
return true;
}
/* Worker function to compute the idom */
static bool computeImmediateDominator(CompilationUnit *cUnit, BasicBlock *bb) {
GrowableList *blockList = &cUnit->blockList;
BitVector *tempBlockV = cUnit->tempBlockV;
BitVectorIterator bvIterator;
BasicBlock *iDom;
if (bb == cUnit->entryBlock) return false;
dvmCopyBitVector(tempBlockV, bb->dominators);
dvmClearBit(tempBlockV, bb->id);
dvmBitVectorIteratorInit(tempBlockV, &bvIterator);
/* Should not see any dead block */
assert(dvmCountSetBits(tempBlockV) != 0);
if (dvmCountSetBits(tempBlockV) == 1) {
iDom = (BasicBlock *) dvmGrowableListGetElement(
blockList, dvmBitVectorIteratorNext(&bvIterator));
bb->iDom = iDom;
} else {
int iDomIdx = dvmBitVectorIteratorNext(&bvIterator);
assert(iDomIdx != -1);
while (true) {
int nextDom = dvmBitVectorIteratorNext(&bvIterator);
if (nextDom == -1) break;
BasicBlock *nextDomBB = (BasicBlock *)
dvmGrowableListGetElement(blockList, nextDom);
/* iDom dominates nextDom - set new iDom */
if (dvmIsBitSet(nextDomBB->dominators, iDomIdx)) {
iDomIdx = nextDom;
}
}
iDom = (BasicBlock *) dvmGrowableListGetElement(blockList, iDomIdx);
/* Set the immediate dominator block for bb */
bb->iDom = iDom;
}
/* Add bb to the iDominated set of the immediate dominator block */
dvmCompilerSetBit(iDom->iDominated, bb->id);
return true;
}
