/*-----------------------------------------------------------------*/
ebbIndex *
iCodeBreakDown (iCode * ic)
{
eBBlock **ebbs = NULL;
iCode *loop = ic;
ebbIndex *ebbi;
ebbi = Safe_alloc (sizeof (ebbIndex));
ebbi->count = 0;
ebbi->dfOrder = NULL; /* no depth first order information yet */
/* allocate for the first entry */
ebbs = Safe_alloc (sizeof (eBBlock *));
ebbi->bbOrder = ebbs;
while (loop)
{
/* convert 2 block */
eBBlock *ebb = iCode2eBBlock (loop);
loop = ebb->ech->next;
ebb->ech->next = NULL; /* mark the end of this chain */
if (loop)
loop->prev = NULL;
ebb->bbnum = ebbi->count; /* save this block number */
/* put it in the array */
ebbs[(ebbi->count)++] = ebb;
/* allocate for the next one. Remember to clear the new */
/* pointer at the end, that was created by realloc. */
ebbs = Safe_realloc (ebbs, (ebbi->count + 1) * sizeof (eBBlock *));
ebbi->bbOrder = ebbs;
ebbs[ebbi->count] = 0;
/* if this one ends in a goto or a conditional */
/* branch then check if the block it is going */
/* to already exists, if yes then this could */
/* be a loop, add a preheader to the block it */
/* goes to if it does not already have one */
if (ebbs[(ebbi->count) - 1]->ech &&
(ebbs[(ebbi->count) - 1]->ech->op == GOTO ||
ebbs[(ebbi->count) - 1]->ech->op == IFX))
{
symbol *label;
eBBlock *destBlock;
if (ebbs[(ebbi->count) - 1]->ech->op == GOTO)
label = IC_LABEL (ebbs[(ebbi->count) - 1]->ech);
else if (!(label = IC_TRUE (ebbs[(ebbi->count) - 1]->ech)))
label = IC_FALSE (ebbs[(ebbi->count) - 1]->ech);
if ((destBlock = eBBWithEntryLabel (ebbi, label)) &&
destBlock->preHeader == NULL &&
otherPathsPresent (ebbs, destBlock))
{
symbol *preHeaderLabel = newiTempLoopHeaderLabel (1);
int i, j;
eBBlock *pBlock;
/* go thru all block replacing the entryLabel with new label */
/* till we reach the block , then we insert a new ebblock */
for (i = 0; i < (ebbi->count); i++)
{
if (ebbs[i] == destBlock)
break;
replaceLabel (ebbs[i], label, preHeaderLabel);
}
(ebbi->count)++;
/* if we have stopped at the block , allocate for an extra one */
ebbs = Safe_realloc (ebbs, (ebbi->count + 1) * sizeof (eBBlock *));
ebbi->bbOrder = ebbs;
ebbs[ebbi->count] = 0;
/* then move the block down one count */
pBlock = ebbs[j = i];
for (i += 1; i < (ebbi->count); i++)
{
eBBlock *xBlock;
xBlock = ebbs[i];
ebbs[i] = pBlock;
ebbs[i]->bbnum = i;
pBlock = xBlock;
}
destBlock->preHeader = ebbs[j] = neweBBlock ();
ebbs[j]->bbnum = j;
ebbs[j]->entryLabel = preHeaderLabel;
ebbs[j]->sch = ebbs[j]->ech = newiCodeLabelGoto (LABEL, preHeaderLabel);
ebbs[j]->sch->filename = destBlock->sch->filename;
ebbs[j]->sch->lineno = destBlock->sch->lineno;
}
}
}
/* mark the end */
ebbs[ebbi->count] = NULL;
return ebbi;
}
/*-----------------------------------------------------------------*/
static void
eBBSuccessors (ebbIndex * ebbi)
{
eBBlock ** ebbs = ebbi->bbOrder;
int count = ebbi->count;
int i = 0;
/* for all the blocks do */
for (; i < count; i++)
{
iCode *ic;
if (ebbs[i]->noPath)
continue;
ebbs[i]->succVect = newBitVect (count);
/* if the next on exists & this one does not */
/* end in a GOTO or RETURN then the next is */
/* a natural successor of this. Note we have */
/* consider eBBlocks with no instructions */
if (ebbs[i + 1])
{
if (ebbs[i]->ech)
{
bool foundNoReturn = FALSE;
if (ebbs[i]->ech->op == CALL || ebbs[i]->ech->op == PCALL)
{
sym_link *type = operandType (IC_LEFT (ebbs[i]->ech));
if (IS_FUNCPTR (type))
type = type->next;
if (type && FUNC_ISNORETURN (type))
foundNoReturn = TRUE;
}
if (!foundNoReturn &&
ebbs[i]->ech->op != GOTO &&
ebbs[i]->ech->op != RETURN &&
ebbs[i]->ech->op != JUMPTABLE)
{
int j = i + 1;
while (ebbs[j] && ebbs[j]->noPath)
j++;
addSuccessor (ebbs[i], ebbs[j]); /* add it */
}
else
{
if (i && ebbs[i-1]->ech && ebbs[i-1]->ech->op==IFX) {
ebbs[i]->isConditionalExitFrom=ebbs[i-1];
}
}
} /* no instructions in the block */
/* could happen for dummy blocks */
else
addSuccessor (ebbs[i], ebbs[i + 1]);
}
/* go thru all the instructions: if we find a */
/* goto or ifx or a return then we have a succ */
if ((ic = ebbs[i]->ech))
{
eBBlock *succ;
/* special case for jumptable */
if (ic->op == JUMPTABLE)
{
symbol *lbl;
for (lbl = setFirstItem (IC_JTLABELS (ic)); lbl;
lbl = setNextItem (IC_JTLABELS (ic)))
addSuccessor (ebbs[i],
eBBWithEntryLabel (ebbi, lbl));
}
else
{
succ = NULL;
/* depending on the instruction operator */
switch (ic->op)
{
case GOTO: /* goto has edge to label */
succ = eBBWithEntryLabel (ebbi, ic->label);
break;
case IFX: /* conditional jump */
/* if true label is present */
if (IC_TRUE (ic))
succ = eBBWithEntryLabel (ebbi, IC_TRUE (ic));
else
succ = eBBWithEntryLabel (ebbi, IC_FALSE (ic));
break;
case RETURN: /* block with return */
succ = eBBWithEntryLabel (ebbi, returnLabel);
break;
}
/* if there is a successor add to the list */
/* if it is not already present in the list */
if (succ)
addSuccessor (ebbs[i], succ);
}
}
}
}
