void dvmInitializeSSAConversion(CompilationUnit *cUnit)
{
int i;
int numDalvikReg = cUnit->pCodeItem->item->registersSize;
cUnit->ssaToDalvikMap = dvmCompilerNew(sizeof(GrowableList), false);
dvmInitGrowableList(cUnit->ssaToDalvikMap, numDalvikReg);
cUnit->numSSARegs = numDalvikReg;
LOG(">>>>>>>>>>>>>>>The function is %s<<<<<<<<<<<<<<<<<<\n", __func__);
LOG("cUnit->numSSARegs is %d\n", cUnit->numSSARegs);
for(i = 0; i < numDalvikReg; i++) {
dvmInsertGrowableList(cUnit->ssaToDalvikMap, (void *)ENCODE_REG_SUB(i, 0));
}
cUnit->dalvikToSSAMap = dvmCompilerNew(sizeof(int) * numDalvikReg, false);
for (i = 0; i < numDalvikReg; i++) {
cUnit->dalvikToSSAMap[i] = i;
}
/* 这里暂时作用不知道，所以删除
for (i = 0; i < cUnit->numBlocks; i++) {
BasicBlock *bb = cUnit->blockList[i];
if (bb->blockType == kDalvikByteCode ||
bb->blockType == kTraceEntryBlock) {
bb->dataFlowInfo = dvmCompilerNew(sizeof(BasicBlockDataFlow), true);
}
}
*/
}
/* Sort the blocks by the Depth-First-Search pre-order */
static void computeDFSOrder(CompilationUnit *cUnit) {
/* Initialize or reset the DFS order list */
if (cUnit->dfsOrder.elemList == NULL) {
dvmInitGrowableList(&cUnit->dfsOrder, cUnit->numBlocks);
} else {
/* Just reset the used length on the counter */
cUnit->dfsOrder.numUsed = 0;
}
dvmCompilerDataFlowAnalysisDispatcher(cUnit, dvmCompilerClearVisitedFlag,
kAllNodes,
false /* isIterative */);
recordDFSPreOrder(cUnit, cUnit->entryBlock);
cUnit->numReachableBlocks = cUnit->dfsOrder.numUsed;
}
/* Compute dominators, immediate dominator, and dominance fronter */
static void computeDominators(CompilationUnit *cUnit) {
int numReachableBlocks = cUnit->numReachableBlocks;
int numTotalBlocks = cUnit->blockList.numUsed;
/* Initialize domination-related data structures */
dvmCompilerDataFlowAnalysisDispatcher(cUnit, initializeDominationInfo,
kReachableNodes,
false /* isIterative */);
/* Set the dominator for the root node */
dvmClearAllBits(cUnit->entryBlock->dominators);
dvmSetBit(cUnit->entryBlock->dominators, cUnit->entryBlock->id);
if (cUnit->tempBlockV == NULL) {
cUnit->tempBlockV = dvmCompilerAllocBitVector(numTotalBlocks,
false /* expandable */);
} else {
dvmClearAllBits(cUnit->tempBlockV);
}
dvmCompilerDataFlowAnalysisDispatcher(cUnit, computeBlockDominators,
kPreOrderDFSTraversal,
true /* isIterative */);
cUnit->entryBlock->iDom = NULL;
dvmCompilerDataFlowAnalysisDispatcher(cUnit, computeImmediateDominator,
kReachableNodes,
false /* isIterative */);
/*
* Now go ahead and compute the post order traversal based on the
* iDominated sets.
*/
if (cUnit->domPostOrderTraversal.elemList == NULL) {
dvmInitGrowableList(&cUnit->domPostOrderTraversal, numReachableBlocks);
} else {
cUnit->domPostOrderTraversal.numUsed = 0;
}
computeDomPostOrderTraversal(cUnit, cUnit->entryBlock);
assert(cUnit->domPostOrderTraversal.numUsed ==
(unsigned) cUnit->numReachableBlocks);
/* Now compute the dominance frontier for each block */
dvmCompilerDataFlowAnalysisDispatcher(cUnit, computeDominanceFrontier,
kPostOrderDOMTraversal,
false /* isIterative */);
}