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cfg.c
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cfg.c
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/***********************************************************************************
Copyright 2014 Arizona Board of Regents; all rights reserved.
This software is being provided by the copyright holders under the
following license. By obtaining, using and/or copying this software, you
agree that you have read, understood, and will comply with the following
terms and conditions:
Permission to use, copy, modify, and distribute this software and its
documentation for any purpose and without fee or royalty is hereby granted,
provided that the full text of this notice appears on all copies of the
software and documentation or portions thereof, including modifications,
that you make.
This software is provided "as is," and copyright holders make no
representations or warranties, expressed or implied. By way of example, but
not limitation, copyright holders make no representations or warranties of
merchantability or fitness for any particular purpose or that the use of the
software or documentation will not infringe any third party patents,
copyrights, trademarks or other rights. Copyright holders will bear no
liability for any use of this software or documentation.
The name and trademarks of copyright holders may not be used in advertising
or publicity pertaining to the software without specific, written prior
permission. Title to copyright in this software and any associated
documentation will at all times remain with copyright holders.
***********************************************************************************/
/*
* cfg.c
*
* Created on: May 3, 2011
* Author: genlu
*/
#include <stdlib.h>
#include <assert.h>
#include "al_helper.h"
#include "cfg.h"
//set to 0 in buildBasicBlockList()
static int blockIdCtr;
static int edgeIdCtr;
//initialized in buildDFSTree()
static int DFSTreeNodeCount;
//set to 0 in buildNaturalLoopList()
static int loopIdCtr;
/*
* compare 2 ADDRESS, return 0 is equal
*/
int addressCompare(void *a1, void *a2){
return (ADDRESS) a1 - (ADDRESS) a2;
}
/*
* compare 2 BasicBlock by id, return 0 is equal
*/
int blockIdCompare(void *i1, void *i2){
assert(i1 && i2);
return ((BasicBlock *)i1)->id - ((BasicBlock *)i2)->id;
}
/*
* compare 2 BasicBlock by the address of their first instruction
* return 0 if equal
*/
int blockAddrCompare(void *i1, void *i2){
assert(i1 && i2);
return ((BasicBlock *)i1)->addr - ((BasicBlock *)i2)->addr;
}
/*
* compare 2 basic blocks based on if they are belonging to the same function
*/
int blockInFunctionCompare(void *i1, void *i2){
assert(i1 && i2);
return ((BasicBlock *)i1)->inFunction - ((BasicBlock *)i2)->inFunction;
}
/*
* compare 2 BlockEdge by id
*/
int edgeIdCompare(void *i1, void *i2){
assert(i1 && i2);
return ((BlockEdge *)i1)->id - ((BlockEdge *)i2)->id;
}
/*
* compare 2 blockEdge by their head and tail block
* return 0 if they have the same end nodes (and direction)
*/
int edgeBlockIdCompare(void *i1, void *i2){
assert(i1 && i2);
if(((BlockEdge *)i1)->tail->id==((BlockEdge *)i2)->tail->id){
return ((BlockEdge *)i1)->head->id - ((BlockEdge *)i2)->head->id;
}else
return ((BlockEdge *)i1)->tail->id - ((BlockEdge *)i2)->tail->id;
}
/*
* InstrIsEqual
* takes two instructions, returns true if they are the same, false ow
* "same" defined as same address and same name.
*/
bool instrIsEqual(Instruction *instr1, Instruction *instr2) {
bool isEqual = false;
if(instr1->addr == instr2->addr) {
if(strcmp(instr1->opName, instr2->opName) == 0) {
isEqual = true;
}
}
return (isEqual);
}
/*
* print info of Edges in/out given BasicBlock
*/
void printEdges(BasicBlock *block){
BlockEdge *edge = NULL;
int i;
printf("inbound Edges of block #%d:\n", block->id);
for(i=0;i<al_size(block->preds);i++){
edge = al_get(block->preds, i);
printf("%c%c%c%c%c %d -> %d : %d\n",
EDGE_HAS_FLAG(edge, EDGE_IN_DFST)?'*':'-',
EDGE_HAS_FLAG(edge, EDGE_IS_RETREAT)?'R':'-',
EDGE_HAS_FLAG(edge, EDGE_IS_BACK_EDGE)?'B':'-',
EDGE_HAS_FLAG(edge, EDGE_IS_BRANCHED_PATH)?'J':'-',
EDGE_HAS_FLAG(edge, EDGE_IS_ADJACENT_PATH)?'A':'-',
edge->tail->id, edge->head->id, edge->count);
}
printf("outbound Edges of block #%d:\n", block->id);
for(i=0;i<al_size(block->succs);i++){
edge = al_get(block->succs, i);
printf("%c%c%c%c%c %d -> %d : %d\n",
EDGE_HAS_FLAG(edge, EDGE_IN_DFST)?'*':'-',
EDGE_HAS_FLAG(edge, EDGE_IS_RETREAT)?'R':'-',
EDGE_HAS_FLAG(edge, EDGE_IS_BACK_EDGE)?'B':'-',
EDGE_HAS_FLAG(edge, EDGE_IS_BRANCHED_PATH)?'J':'-',
EDGE_HAS_FLAG(edge, EDGE_IS_ADJACENT_PATH)?'A':'-',
edge->tail->id, edge->head->id, edge->count);
}
}
/*
* print detailed info of given BasicBlock
*/
void printBasicBlock(BasicBlock *block) {
int i, size;
printf("=================================================================\n");
printf("BBL: %3d [ ADDR %lX ]\tdfn = %3d\tCount = %3d ]\n", block->id, block->addr, block->dfn, block->count);
printf("%s\t%s\n", BBL_HAS_FLAG(block, BBL_IS_FUNC_ENTRY)?"FUNC_ENTRY":"-", BBL_HAS_FLAG(block, BBL_IS_FUNC_RET)?"FUNC_RET":"-");
printf("TYPE: ");
switch(block->type){
case BT_FALL_THROUGH:
printf("FALL_THROUGH");
break;
case BT_1_BRANCH:
printf("1_WAY_BRANCH");
break;
case BT_2_BRANCH:
printf("2_WAY_BRANCH");
break;
case BT_N_BRANCH:
printf("N_WAY_BRANCH");
break;
case BT_SCRIPT_INVOKE:
printf("SCRIPT_INVOKE");
break;
case BT_RET:
if(BBL_HAS_FLAG(block, BBL_IS_HALT_NODE)){
//todo: better check
//assert(al_size(block->succs)==0);
printf("HALT");
}
else
printf("RETURN");
break;
case BT_AUG_EXIT:
printf("AUGMENTED_EXIT");
break;
default:
printf("ERROR: unknown block type");
}
printf("\n");
if(block->lastInstr){
assert(block->type!=BT_AUG_EXIT);
printf("Last Instruction:\t%lx %s\n", block->lastInstr->addr, block->lastInstr->opName);
}
/********************* PREDECESSORS ********************/
printf("PREDS: ");
size = al_size(block->preds);
for (i = 0; i < size; i++) {
BasicBlock *next = (BasicBlock *)((BlockEdge *)al_get(block->preds, i))->tail;
printf("%d; ", next->id);
}
printf("\n");
/********************* SUCCESSORS *********************/
printf("SUCCS: ");
size = al_size(block->succs);
for (i = 0; i < size; i++) {
BasicBlock *next = (BasicBlock *)((BlockEdge *)al_get(block->succs, i))->head;
printf("%d; ", next->id);
}
printf("\n");
printEdges(block);
}
/*
* print detail info of given BasicBlock list
*/
void printBasicBlockList(ArrayList *blockList) {
int i, sz = al_size(blockList);
BasicBlock *block;
printf("\nBasic Block List:\n");
for (i = 0; i < sz; i++) {
block = (BasicBlock *)al_get(blockList, i);
printBasicBlock(block);
}
printf("=================================================================\n");
}
/*
* find all the leaders (instruction) in the InstrList given,
* leaders returned as an ArrayList(set) of Instruction*
*/
ArrayList *findLeaders(InstrList *iList){
Instruction *temp_ins;
ArrayList *leaders = al_newGeneric(AL_LIST_SET, addressCompare, refPrint, NULL);
int i=0;
//add first instr into leader list
Instruction *instr = getInstruction(iList, i);
al_add(leaders, (void *)(instr->addr));
for(i=0;i<iList->numInstrs;i++){
Instruction *instr = getInstruction(iList, i);
//ignore non-jump instructions and native invocations
if(!isBranch(iList, instr) &&
!isRetInstruction(iList, instr) &&
!(isInvokeInstruction(iList, instr) && INSTR_HAS_FLAG(instr, INSTR_IS_SCRIPT_INVOKE))
)
continue;
/* add:
* instr as target of jump
* instr immediately after jump
*/
if(isBranch(iList, instr)){
if(!instr->jmpOffset){
printInstruction(instr);
}
assert(instr->jmpOffset);
al_add(leaders, (void *)(instr->addr + instr->jmpOffset));
assert(instr->length>0);
al_add(leaders, (void *)(instr->addr + instr->length));
}
else if(isRetInstruction(iList, instr)){
if(i < iList->numInstrs-1){
temp_ins = getInstruction(iList, i+1);
al_add(leaders, (void *)(temp_ins->addr));
}
}
else{ //non-native invoke and document.write() which generate code
if(i < iList->numInstrs-1){
assert(isInvokeInstruction(iList, instr) && INSTR_HAS_FLAG(instr, INSTR_IS_SCRIPT_INVOKE));
temp_ins = getInstruction(iList, i+1);
al_add(leaders, (void *)(temp_ins->addr));
}
}
}
return leaders;
}
/*
* create an edge
*/
BlockEdge *createBlockEdge(void){
BlockEdge *newEdge = (BlockEdge *)malloc(sizeof(BlockEdge));
assert(newEdge);
newEdge->id = edgeIdCtr++;
newEdge->flags = 0;
newEdge->count = 0;
newEdge->tail = newEdge->head = NULL;
return newEdge;
}
/*
* destroy an edge, but won't touch the BasicBlocks pointed by head and tail
*/
void destroyBlockEdge(void *edge){
if(edge!=NULL)
free((BlockEdge *)edge);
edge = NULL;
}
/*
* mark basicBlock start and end, based on the given list of leaders.
*/
void markBasicBlockBoundary(InstrList *iList, ArrayList *leaders){
Instruction *instr;
int i;
for(i=0;i<iList->numInstrs;i++){
instr = getInstruction(iList, i);
if(al_contains(leaders, (void *)(instr->addr))){
INSTR_SET_FLAG(instr, INSTR_IS_BBL_START);
if(i>0){
instr = getInstruction(iList, i-1);
INSTR_SET_FLAG(instr, INSTR_IS_BBL_END);
}
}
}
instr = getInstruction(iList, iList->numInstrs-1);
INSTR_SET_FLAG(instr, INSTR_IS_BBL_END);
//printInstruction(instr);
}
/*
* create a basicBlock
* dominator list is set to NULL at this moment
*/
BasicBlock *createBasicBlock(void){
BasicBlock *new = (BasicBlock *)malloc(sizeof(BasicBlock));
assert(new);
if(!new)
return NULL;
new->id = blockIdCtr++;
new->addr = new->end_addr = new->flags = new->count = 0;
new->calltarget = NULL;
new->instrs = al_newGeneric(AL_LIST_SET, insCompareByAddr, refPrint, dealloc);
/* new->preds = al_newGeneric(AL_LIST_SET, blockIdCompare, NULL, NULL);
new->succs = al_newGeneric(AL_LIST_SET, blockIdCompare, NULL, NULL);*/
new->preds = al_newGeneric(AL_LIST_SET, edgeBlockIdCompare, NULL, destroyBlockEdge);
new->succs = al_newGeneric(AL_LIST_SET, edgeBlockIdCompare, NULL, destroyBlockEdge);
new->dfn = -1; //depth-first number
new->dominators = NULL;//al_newGeneric(AL_LIST_SET, blockIdCompare, NULL, NULL);
new->dominate = NULL;
new->immDomPreds = NULL;
new->immDomSuccs = NULL;
new->reverseDominators = NULL;
new->reverseDominate = NULL;
new->reverseImmDomPreds = NULL;
new->reverseImmDomSuccs = NULL;
new->reverseDomFrontier = NULL;
new->type = BT_UNKNOWN;
new->flags = 0;
new->inFunction = 0;
assert(new->preds && new->succs);
return new;
}
/*
* DestroyBbl(bbl) -- deallocate the block bbl as well as its components.
* CAUTION: all the blocks and edges will be freed after this call!
*/
void destroyBasicBlock(void *block) {
BasicBlock *bbl;
if(!block)
return;
bbl = (BasicBlock *)block;
if(bbl->instrs)
al_free(bbl->instrs);
if(bbl->preds)
al_free(bbl->preds);
if(bbl->succs)
al_freeWithElements(bbl->succs);
bbl->instrs = bbl->preds = bbl->succs = NULL;
if(bbl->dominators)
al_free(bbl->dominators);
if(bbl->dominate)
al_freeWithElements(bbl->dominate);
if(bbl->immDomPreds){
al_free(bbl->immDomPreds);
//al_freeWithElements(bbl->immDomPreds);
bbl->immDomPreds=NULL;
}
if(bbl->immDomSuccs){
al_freeWithElements(bbl->immDomSuccs);
bbl->immDomSuccs=NULL;
}
if(bbl->reverseDominators)
al_free(bbl->reverseDominators);
if(bbl->reverseDominate)
al_freeWithElements(bbl->reverseDominate);
if(bbl->reverseImmDomPreds){
al_freeWithElements(bbl->reverseImmDomPreds);
bbl->reverseImmDomPreds=NULL;
}
if(bbl->reverseImmDomSuccs){
al_free(bbl->reverseImmDomSuccs);
bbl->reverseImmDomSuccs=NULL;
}
if(bbl->reverseDomFrontier){
al_free(bbl->reverseDomFrontier);
}
bbl->id = -1;
free(bbl);
bbl=NULL;
return;
}
/*
* if flag==1, then don't free pred, if flag==2, then don't free succs,
* else free both
*/
void destroyBasicBlockForConCat(BasicBlock *block, int flag) {
BasicBlock *bbl;
if(!block)
return;
bbl = block;
if(bbl->instrs)
al_free(bbl->instrs);
if(bbl->preds && flag!=1)
al_free(bbl->preds);
if(bbl->succs && flag!=2)
al_freeWithElements(bbl->succs);
bbl->instrs = bbl->preds = bbl->succs = NULL;
if(bbl->dominators)
al_free(bbl->dominators);
if(bbl->dominate)
al_freeWithElements(bbl->dominate);
bbl->id = -1;
free(bbl);
bbl=NULL;
return;
}
/*
* Blocks will be considered same, if they have the same instrs (decided by its address)
* in the same order
*/
BasicBlock *getBlockFromInstrs(ArrayList *bbls, ArrayList *instrs) {
BasicBlock *returnBbl = NULL;
int i, bblSize = al_size(bbls);
int iSize = al_size(instrs);
for(i = 0; i < bblSize; i++) {
bool sameBbl = true;
BasicBlock *nextBbl = (BasicBlock *)al_get(bbls, i);
int j, bblInstrSize = al_size(nextBbl->instrs);
if(iSize != bblInstrSize) {
//instr lists cannot be equal
continue;
}
for(j = 0; j < bblInstrSize; j++) {
Instruction *nextBblInstr = (Instruction *)al_get(nextBbl->instrs, j);
Instruction *nextInstr = (Instruction *)al_get(instrs, j);
if(!instrIsEqual(nextBblInstr, nextInstr)) {
sameBbl = false;
break;
}
}
if(sameBbl) {
returnBbl = nextBbl;
break;
}
}
return (returnBbl);
}
BasicBlock *findBasicBlockFromListByAddr(ArrayList *blockList, ADDRESS addr){
assert(blockList);
int i;
BasicBlock *block;
for(i=0;i<al_size(blockList);i++){
block = al_get(blockList, i);
if(block->addr == addr)
return block;
}
return NULL;
}
BasicBlock *findBasicBlockFromListByID(ArrayList *blockList, int id){
assert(blockList);
int i;
BasicBlock *block;
for(i=0;i<al_size(blockList);i++){
block = al_get(blockList, i);
if(block->id == id)
return block;
}
return NULL;
}
/*
* main routine for create blocks and CFG
* most of work is done here, requires
* the block boundary marked in advance
*/
ArrayList *buildBasicBlockList(InstrList *iList){
//TODO sub dealloc
blockIdCtr=0;
edgeIdCtr=0;
ArrayList *blockList = al_newGeneric(AL_LIST_SORTED, blockIdCompare, NULL, destroyBasicBlock);
int i = 0;
int size = iList->numInstrs;
Instruction *instr = NULL, *lastInstr = NULL;
BasicBlock *block = createBasicBlock();
BBL_SET_FLAG(block, BBL_IS_ENTRY_NODE);
BasicBlock *prev = NULL;
BlockEdge *edge = NULL;
for (i = 0; i < size; i++) {
instr = getInstruction(iList, i);
al_add(block->instrs, instr);
instr->inBlock = block;
if(INSTR_HAS_FLAG(instr,INSTR_IS_BBL_END)) {
/*
* End of bbl, add to list and create "edges"
*/
BasicBlock *existingBbl = getBlockFromInstrs(blockList, block->instrs);
if(existingBbl) {
//use the existing block
int jj;
for(jj=0;jj<al_size(block->instrs);jj++){
Instruction *tempInstr = (Instruction *)al_get(block->instrs, jj);
tempInstr->inBlock = existingBbl;
}
destroyBasicBlock((void *)block);
block = existingBbl;
block->count++;
} else {
//we found a new block, add it to the list
al_add(blockList, block);
block->count = 1;
block->addr = ((Instruction *)(al_get(block->instrs, 0)))->addr;
block->end_addr = instr->addr;
block->lastInstr = instr;
if(INSTR_HAS_FLAG(instr,INSTR_IS_1_BRANCH))
block->type = BT_1_BRANCH;
else if(INSTR_HAS_FLAG(instr,INSTR_IS_2_BRANCH))
block->type = BT_2_BRANCH;
else if(INSTR_HAS_FLAG(instr,INSTR_IS_N_BRANCH))
block->type = BT_N_BRANCH;
else if(INSTR_HAS_FLAG(instr,INSTR_IS_SCRIPT_INVOKE)){
block->type = BT_SCRIPT_INVOKE;
}
/*
* it is possible in the slice the last instr is not stop/ret
* we still have to set it to BT_RET
*/
else if(INSTR_HAS_FLAG(instr,INSTR_IS_RET) || i==size-1)
block->type = BT_RET;
else
block->type = BT_FALL_THROUGH;
}
//add "edges" to structs
if(prev) {
int added = 0;
//create an edge: prev->block
edge = createBlockEdge();
edge->tail = prev;
edge->head = block;
edge->count = 1;
if(prev->type == BT_SCRIPT_INVOKE){
prev->calltarget = block;
EDGE_SET_FLAG(edge, EDGE_IS_SCRIPT_INVOKE);
}
else if(prev->type == BT_2_BRANCH){
assert(lastInstr != NULL);
assert(lastInstr->jmpOffset!=0);
//printf("lastInstr->jmpOffset %d\n", lastInstr->jmpOffset);
if(lastInstr->jmpOffset < 0){
if(block->addr > lastInstr->addr){
//then this block is not branched block
// XXX changed, but might be wrong here -08/10/2011
EDGE_SET_FLAG(edge, EDGE_IS_ADJACENT_PATH);
}else{
EDGE_SET_FLAG(edge, EDGE_IS_BRANCHED_PATH);
}
}else{
if(block->addr < lastInstr->addr + lastInstr->jmpOffset){
//then this block is not branched block
EDGE_SET_FLAG(edge, EDGE_IS_ADJACENT_PATH);
}else{
EDGE_SET_FLAG(edge, EDGE_IS_BRANCHED_PATH);
}
}
}
else if(prev->type == BT_RET)
EDGE_SET_FLAG(edge, EDGE_IS_RET);
if(!al_contains(prev->succs, edge)){
al_add(prev->succs, edge);
added++;
}
if(!al_contains(block->preds, edge)){
al_add(block->preds, edge);
added++;
}
if(!added){
BlockEdge *e = (BlockEdge *)al_get(block->preds, al_indexOf(block->preds, edge));
e->count++;
destroyBlockEdge(edge);
}
}
if(lastInstr != NULL) {
lastInstr->nextBlock = block;
}
lastInstr = instr;
if(i < (size-1)) {
//there are more instructions left, so at least one more block
//set new block to be used by subsequent instructions
prev = block;
block = createBasicBlock();
} //else we're done
else{
BBL_SET_FLAG(block, BBL_IS_HALT_NODE);
}
}
}
/*
* try to discover all complement edges
*/
for(i=0;i<al_size(blockList);i++){
block = (BasicBlock *)al_get(blockList, i);
if(block->type==BT_2_BRANCH){
//at least one branch target have to be reached.
//If only one is reached, we need to add a complement edge to the other
if(al_size(block->succs)!=2){
assert(al_size(block->succs)==1);
BasicBlock *branchTakenBlock;
BasicBlock *branchMissingBlock;
BlockEdge *branchTakenEdge;
BlockEdge *branchMissingEdge;
ADDRESS branchMissingAddress;
fprintf(stderr, "block%d missing an edge\n", block->id);
//get the branch instr (last instr in block)
int temp_i = al_size(block->instrs)-1;
instr = al_get(block->instrs, temp_i);
assert(INSTR_HAS_FLAG(instr,INSTR_IS_2_BRANCH));
//calculate missing branch target address
branchTakenEdge = al_get(block->succs,0);
branchTakenBlock = branchTakenEdge->head;
if(EDGE_HAS_FLAG(branchTakenEdge, EDGE_IS_ADJACENT_PATH)){
branchMissingAddress = instr->addr + instr->jmpOffset;
}else{
branchMissingAddress = instr->addr + instr->length;
}
//find the missing target block by address
branchMissingBlock = findBasicBlockFromListByAddr(blockList, branchMissingAddress);
if(branchMissingBlock){
//add the complement-edge to block->succ
branchMissingEdge = createBlockEdge();
branchMissingEdge->count = 0;
branchMissingEdge->tail = block;
branchMissingEdge->head = branchMissingBlock;
EDGE_SET_FLAG(branchMissingEdge, EDGE_IS_COMPLEMENT);
if(EDGE_HAS_FLAG(branchTakenEdge, EDGE_IS_ADJACENT_PATH)){
EDGE_SET_FLAG(branchMissingEdge, EDGE_IS_BRANCHED_PATH);
}else{
EDGE_SET_FLAG(branchMissingEdge, EDGE_IS_ADJACENT_PATH);
}
al_add(block->succs, branchMissingEdge);
al_add(branchMissingBlock->preds, branchMissingEdge);
}else
continue;
}
else{
continue;
}
}else if(block->type==BT_N_BRANCH){
//TODO
assert(0);
}
}
return (blockList);
}
void destroyBasicBlockList(ArrayList *blockList){
if(!blockList)
return;
/* int i;
BasicBlock *bbl;
for(i=0;i<al_size(blockList);i++){
bbl = al_get(blockList, i);
destroyBasicBlock(bbl);
bbl = NULL;
}
free(blockList->al_elements);
blockList->al_elements = NULL;
free(blockList);
blockList = NULL;*/
al_freeWithElements(blockList);
}
/*
* do-it-all:
* find leaders-> mark blocks-> create blocks and CFG
* return a list of BasicBlocks
*/
ArrayList *buildDynamicCFG(InstrList *iList){
ArrayList *leaders;
ArrayList *blockList;
leaders = findLeaders(iList);
printf("\nLeader list:\n");
al_print(leaders);
printf("\n");
markBasicBlockBoundary(iList, leaders);
al_free(leaders);
blockList = buildBasicBlockList(iList);
return blockList;
}
void printDominators(ArrayList *blockList){
int i,j;
BasicBlock *b1, *b2;
printf("\nDominators for each block\n");
for(i=0;i<al_size(blockList);i++){
b1 = (BasicBlock *)al_get(blockList, i);
printf(" Dominators of block %3d:\t", b1->id);
for(j=0;j<al_size(b1->dominators);j++){
b2 = (BasicBlock *)al_get(b1->dominators, j);
printf("%d\t", b2->id);
}
printf("\n");
}
}
void printDomList(ArrayList *blockList){
int i,j;
BasicBlock *b1;
BlockEdge *e;
printf("\nDomListfor each block\n");
for(i=0;i<al_size(blockList);i++){
b1 = (BasicBlock *)al_get(blockList, i);
printf(" blocks dominated by block %3d:\t", b1->id);
for(j=0;j<al_size(b1->dominate);j++){
e = (BlockEdge *)al_get(b1->dominate, j);
assert(EDGE_HAS_FLAG(e, EDGE_IS_DOMINATE));
printf("\t%d\t", e->head->id);
}
printf("\n");
}
}
void printImmDomList(ArrayList *blockList){
int i,j;
BasicBlock *b1;
BlockEdge *e;
printf("\nImm Dom List for each block\n");
for(i=0;i<al_size(blockList);i++){
b1 = (BasicBlock *)al_get(blockList, i);
printf(" blocks immediately dominated by block %3d:\t", b1->id);
for(j=0;j<al_size(b1->immDomSuccs);j++){
e = (BlockEdge *)al_get(b1->immDomSuccs, j);
printf("\t%d\t", e->head->id);
}
printf("\n");
}
}
/*
* return true if block1 dominate block2 in CFG
*/
bool dominate(BasicBlock *block1, BasicBlock *block2){
assert(block1&&block2);
assert(block1->dominate);
int i;
BlockEdge *edge;
for(i=0;i<al_size(block1->dominate);i++){
edge = al_get(block1->dominate, i);
if(edge->head->id == block2->id)
return true;
}
return false;
}
/*
* auxiliary function used by findDominators()
*/
ArrayList *findDominatorHelper(BasicBlock *block){
//printf("findDominatorHelper: id %d\n", block->id);
assert(!BBL_HAS_FLAG(block, BBL_IS_ENTRY_NODE));
assert(!BBL_HAS_FLAG(block, BBL_IS_FUNC_ENTRY));
int i;
ArrayList *dominators, *dominatorsTemp;
BasicBlock *predNode;
/*
* D(n) = {n} 'union' ('intersection' D(p) | for each p 'in' preds(n))
*/
predNode = (BasicBlock *)((BlockEdge *)al_get(block->preds, 0))->tail;
dominators = dominatorsTemp = al_clone(predNode->dominators);
assert(dominators && dominatorsTemp);
for(i=1;i<al_size(block->preds);i++){
predNode = (BasicBlock *)((BlockEdge *)al_get(block->preds, i))->tail;
dominators = al_intersection(dominatorsTemp, predNode->dominators);
al_free(dominatorsTemp);
dominatorsTemp = NULL;
dominatorsTemp = dominators;
}
assert(dominators);
al_add(dominators, (void *)block);
return dominators;
}
/*
* find all the dominators for each basicBlock in the Dynamic CFG
* this function would create an ArrayList(set) dominators for each BasicBlock
*/
void findDominators(ArrayList *blockList){
assert(blockList);
BasicBlock *block, *block2, *block3;
ArrayList *domTemp;
BlockEdge *domEdge;
int change;
int i,j,k;
/* Initialize D(n) for each node n.
* D(n) = {n0}, if n==n0
* D(n) = N (all nodes), otherwise
*/
for(i=0;i<al_size(blockList);i++){
block = al_get(blockList, i);
if(block->dominators){
al_free(block->dominators);
}
//printf("block#%d\t", block->id);
//block 0 is garanteed to be the entry node
if(BBL_HAS_FLAG(block, BBL_IS_ENTRY_NODE)){
//assert(BBL_HAS_FLAG(block, BBL_IS_ENTRY_NODE));
//printf("entry\n");
block->dominators = al_newGeneric(AL_LIST_SET, blockIdCompare, NULL, NULL);
al_add(block->dominators, (void *)block);
}
else if(al_size(block->preds)==0){
assert(BBL_HAS_FLAG(block, BBL_IS_FUNC_ENTRY));
//printf("func_entry\n");
block->dominators = al_newGeneric(AL_LIST_SET, blockIdCompare, NULL, NULL);
al_add(block->dominators, (void *)block);
}
else{
//printf("reg\n");
block->dominators = al_clone(blockList);
block->dominators->al_type = AL_LIST_SET;
block->dominators->al_print = NULL;
block->dominators->al_free = NULL;
}
}
//printDominators(blockList);
do{
change = 0;
//for each node != n0
for(i=0;i<al_size(blockList);i++){
block = (BasicBlock *)al_get(blockList,i);
if(BBL_HAS_FLAG(block, BBL_IS_FUNC_ENTRY)||BBL_HAS_FLAG(block, BBL_IS_ENTRY_NODE))
continue;
domTemp = findDominatorHelper(block);
assert(domTemp);
if(al_setEquals(block->dominators, domTemp)){
al_free(domTemp);
domTemp = NULL;
}else{
al_free(block->dominators);
block->dominators = NULL;
block->dominators = domTemp;
change++;
}
}//end for-loop
}while(change);
//printDominators(blockList);
//calculate block->dominate
for(i=0;i<al_size(blockList);i++){
block = (BasicBlock *)al_get(blockList,i);
if(block->dominate){
al_freeWithElements(block->dominate);
}
block->dominate = al_newGeneric(AL_LIST_SET, edgeBlockIdCompare, NULL, destroyBlockEdge);
for(j=0;j<al_size(block->dominators);j++){
//block2 dominates block
block2 = (BasicBlock *)al_get(block->dominators,j);
domEdge = createBlockEdge();
domEdge->tail = block2;
domEdge->head = block;
EDGE_SET_FLAG(domEdge, EDGE_IS_DOMINATE);
if(!al_contains(block2->dominate, domEdge)){
al_add(block2->dominate, domEdge);
}else{
destroyBlockEdge(domEdge);
}
}
}
//printDomList(blockList);
//construct dom-tree
for(i=0;i<al_size(blockList);i++){
block = (BasicBlock *)al_get(blockList,i);
if(block->immDomPreds){
//al_freeWithElements(block->immDomPreds);
al_free(block->immDomPreds);
block->immDomPreds=NULL;
}
if(block->immDomSuccs){
al_freeWithElements(block->immDomSuccs);
block->immDomSuccs=NULL;
}
block->immDomPreds = al_newGeneric(AL_LIST_SET, edgeBlockIdCompare, NULL, destroyBlockEdge);
block->immDomSuccs = al_newGeneric(AL_LIST_SET, edgeBlockIdCompare, NULL, destroyBlockEdge);
for(j=0;j<al_size(block->dominators);j++){
//block2 dominates block
block2 = (BasicBlock *)al_get(block->dominators,j);
if(block2->id == block->id){
continue;
}
for(k=0;k<al_size(block->dominators);k++){
block3 = (BasicBlock *)al_get(block->dominators,k);
if(block3->id == block->id){
continue;
}
if(!dominate(block3, block2)){
block2 = NULL; //then block2 cannot be the imm dominator of block, set to NULL as a flag
break;
}
}
if(!block2)
continue;
//printf("block%d is imm-dominator of block%d\n", block2->id, block->id);
//then block is imm dominator of block
domEdge = createBlockEdge();
domEdge->tail = block2;
domEdge->head = block;
EDGE_SET_FLAG(domEdge, EDGE_IS_IMM_DOM);