/*-----------------------------------------------------------------------*/
static iCode *
findPointerGetSet (iCode * sic, operand * op)
{
iCode *ic = sic;
for (; ic; ic = ic->next)
{
if ((POINTER_SET (ic) && isOperandEqual (op, IC_RESULT (ic))) ||
(POINTER_GET (ic) && isOperandEqual (op, IC_LEFT (ic))))
return ic;
/* if we find any other usage or definition of op null */
if (IC_RESULT (ic) && isOperandEqual (IC_RESULT (ic), op))
return NULL;
if (IC_RIGHT (ic) && isOperandEqual (IC_RIGHT (ic), op))
return NULL;
if (IC_LEFT (ic) && isOperandEqual (IC_LEFT (ic), op))
return NULL;
}
return NULL;
}
static void visit (set **visited, iCode *ic, const int key)
{
symbol *lbl;
while (ic && !isinSet (*visited, ic) && bitVectBitValue (ic->rlive, key))
{
addSet (visited, ic);
switch (ic->op)
{
case GOTO:
ic = hTabItemWithKey (labelDef, (IC_LABEL (ic))->key);
break;
case RETURN:
ic = hTabItemWithKey (labelDef, returnLabel->key);
break;
case JUMPTABLE:
for (lbl = setFirstItem (IC_JTLABELS (ic)); lbl; lbl = setNextItem (IC_JTLABELS (ic)))
visit (visited, hTabItemWithKey (labelDef, lbl->key), key);
break;
case IFX:
visit (visited, hTabItemWithKey (labelDef, (IC_TRUE(ic) ? IC_TRUE (ic) : IC_FALSE (ic))->key), key);
ic = ic->next;
break;
default:
ic = ic->next;
if (!POINTER_SET (ic) && IC_RESULT (ic) && IS_SYMOP (IC_RESULT (ic)) && OP_SYMBOL_CONST (IC_RESULT (ic))->key == key)
{
addSet (visited, ic);
return;
}
}
}
}
/** Does some transformations to reduce register pressure.
*/
static void
packRegisters (eBBlock * ebp)
{
iCode *ic;
int change = 0;
D (D_ALLOC, ("packRegisters: entered.\n"));
for(;;)
{
change = 0;
/* look for assignments of the form */
/* iTempNN = TRueSym (someoperation) SomeOperand */
/* .... */
/* TrueSym := iTempNN:1 */
for (ic = ebp->sch; ic; ic = ic->next)
{
/* find assignment of the form TrueSym := iTempNN:1 */
if (ic->op == '=' && !POINTER_SET (ic))
change += packRegsForAssign (ic, ebp);
}
if (!change)
break;
}
}
/*-----------------------------------------------------------------*/
void
replaceSymBySym (set * sset, operand * src, operand * dest)
{
set *loop;
eBBlock *rBlock;
/* for all blocks in the set do */
for (loop = sset; loop; loop = loop->next)
{
iCode *ic;
rBlock = loop->item;
/* for all instructions in this block do */
for (ic = rBlock->sch; ic; ic = ic->next)
{
/* if we find usage */
if (ic->op == IFX && isOperandEqual (src, IC_COND (ic)))
{
bitVectUnSetBit (OP_USES (IC_COND (ic)), ic->key);
IC_COND (ic) = operandFromOperand (dest);
OP_USES (dest) = bitVectSetBit (OP_USES (dest), ic->key);
continue;
}
if (isOperandEqual (IC_RIGHT (ic), src))
{
bitVectUnSetBit (OP_USES (IC_RIGHT (ic)), ic->key);
IC_RIGHT (ic) = operandFromOperand (dest);
IC_RIGHT (ic)->isaddr = 0;
OP_USES (dest) = bitVectSetBit (OP_USES (dest), ic->key);
}
if (isOperandEqual (IC_LEFT (ic), src))
{
bitVectUnSetBit (OP_USES (IC_LEFT (ic)), ic->key);
if (POINTER_GET (ic) && IS_ITEMP (dest))
{
IC_LEFT (ic) = operandFromOperand (dest);
IC_LEFT (ic)->isaddr = 1;
}
else
{
IC_LEFT (ic) = operandFromOperand (dest);
IC_LEFT (ic)->isaddr = 0;
}
OP_USES (dest) = bitVectSetBit (OP_USES (dest), ic->key);
}
/* special case for pointer sets */
if (POINTER_SET (ic) && isOperandEqual (IC_RESULT (ic), src))
{
bitVectUnSetBit (OP_USES (IC_RESULT (ic)), ic->key);
IC_RESULT (ic) = operandFromOperand (dest);
IC_RESULT (ic)->isaddr = 1;
OP_USES (dest) = bitVectSetBit (OP_USES (dest), ic->key);
}
}
}
}
static int pattern1 (iCode *sic)
{
/* this is what we do. look for sequences like
iTempX := _SOME_POINTER_;
iTempY := _SOME_POINTER_ + nn ; nn = sizeof (pointed to object) sic->next
_SOME_POINTER_ := iTempY; sic->next->next
either
iTempZ := @[iTempX]; sic->next->next->next
or
*(iTempX) := ..something.. sic->next->next->next
if we find this then transform this to
iTempX := _SOME_POINTER_;
either
iTempZ := @[iTempX];
or
*(iTempX) := ..something..
iTempY := _SOME_POINTER_ + nn ; nn = sizeof (pointed to object)
_SOME_POINTER_ := iTempY; */
/* sounds simple enough so let's start , here I use negative
tests all the way to return if any test fails */
iCode *pgs, *sh, *st;
if (!(sic->next && sic->next->next && sic->next->next->next))
return 0;
if (sic->next->op != '+' && sic->next->op != '-')
return 0;
if (!(sic->next->next->op == '=' &&
!POINTER_SET (sic->next->next)))
return 0;
if (!isOperandEqual (IC_LEFT (sic->next), IC_RIGHT (sic)) ||
!IS_OP_LITERAL (IC_RIGHT (sic->next)))
return 0;
if (operandLitValue (IC_RIGHT (sic->next)) !=
getSize (operandType (IC_RIGHT (sic))->next))
return 0;
if (!isOperandEqual (IC_RESULT (sic->next->next),
IC_RIGHT (sic)))
return 0;
if (!isOperandEqual (IC_RESULT (sic->next), IC_RIGHT (sic->next->next)))
return 0;
if (!(pgs = findPointerGetSet (sic->next->next, IC_RESULT (sic))))
return 0;
/* found the pattern .. now do the transformation */
sh = sic->next;
st = sic->next->next;
/* take the two out of the chain */
sic->next = st->next;
st->next->prev = sic;
/* and put them after the pointer get/set icode */
if ((st->next = pgs->next))
st->next->prev = st;
pgs->next = sh;
sh->prev = pgs;
return 1;
}
/*-----------------------------------------------------------------*/
iCode *
usedInRemaining (operand * op, iCode * ic)
{
iCode *lic = ic;
if (!IS_SYMOP (op))
return 0;
for (; lic; lic = lic->next)
{
/* if the operand is a parameter */
/* then check for calls and return */
/* true if there is a call */
/* if this is a global variable then
return true */
if (lic->op == CALL || lic->op == PCALL)
{
if ((IS_PARM (op) &&
isParameterToCall (IC_ARGS (lic), op)) ||
isOperandGlobal (op))
return lic;
}
if (ic->op == SEND &&
isOperandEqual (IC_LEFT (lic), op))
return lic;
if (SKIP_IC1 (lic))
continue;
/* if ifx then check the condition */
if (lic->op == IFX &&
isOperandEqual (IC_COND (lic), op))
return lic;
if (lic->op == JUMPTABLE &&
isOperandEqual (IC_JTCOND (lic), op))
return lic;
if (IC_RIGHT (lic) &&
isOperandEqual (IC_RIGHT (lic), op))
return lic;
if (IC_LEFT (lic) &&
isOperandEqual (IC_LEFT (lic), op))
return lic;
/* for a pointer assignment usage */
if (POINTER_SET (lic) &&
isOperandEqual (op, IC_RESULT (lic)))
return lic;
else if (IC_RESULT (lic) && isOperandEqual (IC_RESULT (lic), op))
return NULL;
}
return NULL;
}
/*------------------------------------------------------------------*/
static bool
findPrevUseSym (eBBlock *ebp, iCode *ic, symbol * sym)
{
eBBlock * pred;
iCode * uic;
if (ebp->visited)
{
/* already visited: this branch must have been succesfull, */
/* because otherwise the search would have been aborted. */
return TRUE;
}
ebp->visited = 1;
/* search backward in the current block */
for (uic = ic; uic; uic = uic->prev)
{
if (!POINTER_SET (uic) && IS_AUTOSYM (IC_RESULT (uic)))
{
if (IC_RESULT (uic)->key == sym->key)
{
/* Ok, found a definition */
return TRUE;
}
}
/* address taken from symbol? */
if (uic->op == ADDRESS_OF && IS_AUTOSYM (IC_LEFT (uic)))
{
if (IC_LEFT (uic)->key == sym->key)
{
/* Ok, found a definition */
return TRUE;
}
}
}
/* There's no definition in this bblock, */
/* let's have a look at all predecessors. */
pred = setFirstItem (ebp->predList);
if (!pred)
{
/* no more predecessors and nothing found yet :-( */
return FALSE;
}
for (; pred; pred = setNextItem (ebp->predList))
{
/* recurse into all predecessors */
if (!findPrevUseSym (pred, pred->ech, sym))
{
/* found nothing: abort */
return FALSE;
}
}
/* Success! Went through all branches with no abort: */
/* all branches end with a definition */
return TRUE;
}
/*-----------------------------------------------------------------*/
int
usedBetweenPoints (operand * op, iCode * start, iCode * end)
{
iCode *lic = start;
for (; lic != end; lic = lic->next)
{
/* if the operand is a parameter */
/* then check for calls and return */
/* true if there is a call */
if (IS_PARM (op) &&
(lic->op == CALL ||
lic->op == PCALL))
if (isParameterToCall (IC_ARGS (lic), op))
return 1;
if (SKIP_IC2 (lic))
continue;
/* if ifx then check the condition */
if (lic->op == IFX &&
IC_COND (lic)->key == op->key)
return 1;
if (lic->op == JUMPTABLE &&
IC_JTCOND (lic)->key == op->key)
return 1;
if (IC_RIGHT (lic) &&
IC_RIGHT (lic)->key == op->key)
return 1;
if (IC_LEFT (lic) &&
IC_LEFT (lic)->key == op->key)
return 1;
/* for a pointer assignment usage */
if (POINTER_SET (lic) &&
op->key == IC_RESULT (lic)->key)
return 1;
else if (IC_RESULT (lic) && op->key == IC_RESULT (lic)->key)
return 0;
}
return 0;
}
static int implement_lospre_assignment(const assignment_lospre a, T_t &T, G_t &G, const iCode *ic) // Assignment has to be passed as a copy (not reference), since the transformations on the tree-decomposition will invalidate it otherwise.
{
operand *tmpop;
unsigned substituted = 0, split = 0;
typedef typename boost::graph_traits<G_t>::edge_iterator edge_iter_t;
typedef typename boost::graph_traits<G_t>::edge_descriptor edge_desc_t;
std::set<edge_desc_t> calculation_edges; // Use descriptor, not iterator due to possible invalidation of iterators when inserting vertices or edges.
edge_iter_t e, e_end;
for(boost::tie(e, e_end) = boost::edges(G); e != e_end; ++e)
if(!((a.global[boost::source(*e, G)] & true) && !G[boost::source(*e, G)].invalidates) && (a.global[boost::target(*e, G)] & true))
calculation_edges.insert(*e);
if(!calculation_edges.size())
return(0);
#ifdef DEBUG_LOSPRE
std::cout << "Optimizing at " << ic->key << "\n"; std::cout.flush();
#endif
tmpop = newiTempOperand (operandType (IC_RESULT (ic)), TRUE);
tmpop->isvolatile = false;
#ifdef DEBUG_LOSPRE
std::cout << "New tmpop: " << OP_SYMBOL_CONST(tmpop)->name << " "; printTypeChain(operandType (IC_RESULT(ic)), stdout); std::cout << "\n";
#endif
for(typename std::set<edge_desc_t>::iterator i = calculation_edges.begin(); i != calculation_edges.end(); ++i)
{
split_edge(T, G, *i, ic, tmpop);
split++;
}
typedef typename boost::graph_traits<G_t>::vertex_iterator vertex_iter_t;
vertex_iter_t v, v_end;
for(boost::tie(v, v_end) = boost::vertices(G); v != v_end; ++v)
{
if(!G[*v].uses)
continue;
typename boost::graph_traits<G_t>::in_edge_iterator e = in_edges(*v, G).first;
if (a.global.size() <= *v)
continue;
if(!((a.global[*v] & true) && !G[*v].invalidates || boost::source(*e, G) < a.global.size() && (a.global[boost::source(*e, G)] & true)))
continue;
#ifdef DEBUG_LOSPRE
std::cout << "Substituting ic " << G[*v].ic->key << "\n";
#endif
substituted++;
iCode *ic = G[*v].ic;
//if (IC_LEFT (ic) && IS_ITEMP (IC_LEFT (ic)))
// bitVectUnSetBit (OP_SYMBOL (IC_LEFT (ic))->uses, ic->key);
//if (IC_RIGHT (ic) && IS_ITEMP (IC_RIGHT (ic)))
// bitVectUnSetBit (OP_SYMBOL (IC_RIGHT (ic))->uses, ic->key);
IC_RIGHT(ic) = tmpop;
//bitVectSetBit (OP_SYMBOL (IC_RIGHT(ic))->uses, ic->key);
if (!POINTER_SET (ic))
{
IC_LEFT(ic) = 0;
ic->op = '=';
IC_RESULT(ic) = operandFromOperand (IC_RESULT (ic));
IC_RESULT(ic)->isaddr = 0;
}
if(IS_OP_VOLATILE(IC_RESULT (ic)))
continue;
{
typedef typename boost::graph_traits<G_t>::adjacency_iterator adjacency_iter_t;
adjacency_iter_t c, c_end;
boost::tie(c, c_end) = adjacent_vertices(*v, G);
if (c != c_end)
forward_lospre_assignment(G, *c, ic, a);
}
}
if(substituted <= 0)
{
std::cerr << "Introduced " << OP_SYMBOL_CONST(tmpop)->name << ", but did not substitute any calculations.\n";
return (-1);
}
if(substituted < split) // Todo: Remove this warning when optimization for speed instead of code size is implemented!
std::cout << "Introduced " << OP_SYMBOL_CONST(tmpop)->name << ", but did substitute only " << substituted << " calculations, while introducing "<< split << ".\n"; std::cout.flush();
return(1);
}
static void forward_lospre_assignment(G_t &G, typename boost::graph_traits<G_t>::vertex_descriptor i, const iCode *ic, const assignment_lospre& a)
{
typedef typename boost::graph_traits<G_t>::adjacency_iterator adjacency_iter_t;
adjacency_iter_t c, c_end;
operand *tmpop = IC_RIGHT(ic);
const std::pair<int, int> forward(IC_RESULT(ic)->key, IC_RIGHT(ic)->key);
for(;;)
{
if (G[i].forward == forward)
break; // Was here before.
iCode *nic = G[i].ic;
if (isOperandEqual(IC_RESULT(ic), IC_LEFT(nic)) && nic->op != ADDRESS_OF && (!POINTER_GET(nic) || !IS_PTR(operandType(IC_RESULT(nic))) || !IS_BITFIELD(operandType(IC_LEFT(nic))->next) || compareType(operandType(IC_LEFT(nic)), operandType(tmpop)) == 1))
{
bool isaddr = IC_LEFT (nic)->isaddr;
#ifdef DEBUG_LOSPRE
std::cout << "Forward substituted left operand " << OP_SYMBOL_CONST(IC_LEFT(nic))->name << " at " << nic->key << "\n";
#endif
//bitVectUnSetBit (OP_SYMBOL (IC_LEFT (nic))->uses, nic->key);
IC_LEFT(nic) = operandFromOperand (tmpop);
//bitVectSetBit (OP_SYMBOL (IC_LEFT (nic))->uses, nic->key);
IC_LEFT (nic)->isaddr = isaddr;
}
if (isOperandEqual(IC_RESULT(ic), IC_RIGHT(nic)))
{
#ifdef DEBUG_LOSPRE
std::cout << "Forward substituted right operand " << OP_SYMBOL_CONST(IC_RIGHT(nic))->name << " at " << nic->key << "\n";
#endif
//bitVectUnSetBit (OP_SYMBOL (IC_RIGHT (nic))->uses, nic->key);
IC_RIGHT(nic) = operandFromOperand (tmpop);
//bitVectSetBit (OP_SYMBOL (IC_RIGHT (nic))->uses, nic->key);
}
if (POINTER_SET(nic) && isOperandEqual(IC_RESULT(ic), IC_RESULT(nic)) && (!IS_PTR(operandType(IC_RESULT(nic))) || !IS_BITFIELD(operandType(IC_RESULT(nic))->next) || compareType(operandType(IC_RESULT(nic)), operandType(tmpop)) == 1))
{
#ifdef DEBUG_LOSPRE
std::cout << "Forward substituted result operand " << OP_SYMBOL_CONST(IC_RESULT(nic))->name << " at " << nic->key << "\n";
#endif
//bitVectUnSetBit (OP_SYMBOL (IC_RESULT (nic))->uses, nic->key);
IC_RESULT(nic) = operandFromOperand (tmpop);
IC_RESULT(nic)->isaddr = true;
//bitVectSetBit (OP_SYMBOL (IC_RESULT (nic))->uses, nic->key);
}
if (nic->op == LABEL) // Reached label. Continue only if all edges goining here are safe.
{
typedef typename boost::graph_traits<G_t>::in_edge_iterator in_edge_iter_t;
in_edge_iter_t e, e_end;
for (boost::tie(e, e_end) = boost::in_edges(i, G); e != e_end; ++e)
if (G[boost::source(*e, G)].forward != forward)
break;
if(e != e_end)
break;
}
if (isOperandEqual(IC_RESULT (ic), IC_RESULT(nic)) && !POINTER_SET(nic) /*|| G[i].uses*/)
break;
if ((nic->op == CALL || nic->op == PCALL || POINTER_SET(nic)) && IS_TRUE_SYMOP(IC_RESULT(ic)))
break;
G[i].forward = forward;
if (nic->op == GOTO || nic->op == IFX || nic->op == JUMPTABLE)
{
adjacency_iter_t c, c_end;
for(boost::tie(c, c_end) = boost::adjacent_vertices(i, G); c != c_end; ++c)
{
if(!((a.global[i] & true) && !G[i].invalidates) && (a.global[*c] & true)) // Calculation edge
continue;
forward_lospre_assignment(G, *c, ic, a);
}
break;
}
boost::tie(c, c_end) = adjacent_vertices(i, G);
if(c == c_end)
break;
if(!((a.global[i] & true) && !G[i].invalidates) && (a.global[*c] & true)) // Calculation edge
break;
i = *c;
}
}
/*-----------------------------------------------------------------*/
int
killDeadCode (eBBlock ** ebbs, int count)
{
int change = 1;
int gchange = 0;
int i = 0;
/* basic algorithm :- */
/* first the exclusion rules :- */
/* 1. if result is a global or volatile then skip */
/* 2. if assignment and result is a temp & isaddr then skip */
/* since this means array & pointer access, will be taken */
/* care of by alias analysis. */
/* 3. if the result is used in the remainder of the block skip */
/* 4. if this definition does not reach the end of the block */
/* i.e. the result is not present in the outExprs then KILL */
/* 5. if it reaches the end of block & is used by some success */
/* or then skip */
/* else KILL */
/* this whole process is carried on iteratively till no change */
while (1)
{
change = 0;
/* for all blocks do */
for (i = 0; i < count; i++)
{
iCode *ic;
/* for all instructions in the block do */
for (ic = ebbs[i]->sch; ic; ic = ic->next)
{
int kill, j;
kill = 0;
if (SKIP_IC (ic) ||
ic->op == IFX ||
ic->op == RETURN)
continue;
/* if the result is volatile then continue */
if (IC_RESULT (ic) && isOperandVolatile (IC_RESULT (ic), FALSE))
continue;
/* if the result is a temp & isaddr then skip */
if (IC_RESULT (ic) && POINTER_SET (ic))
continue;
/* if the result is used in the remainder of the */
/* block then skip */
if (usedInRemaining (IC_RESULT (ic), ic->next))
continue;
/* does this definition reach the end of the block
or the usage is zero then we can kill */
if (!bitVectBitValue (ebbs[i]->outDefs, ic->key))
kill = 1; /* if not we can kill it */
else
{
/* if this is a global variable or function parameter */
/* we cannot kill anyway */
if (isOperandGlobal (IC_RESULT (ic)) ||
(OP_SYMBOL (IC_RESULT (ic))->_isparm &&
!OP_SYMBOL (IC_RESULT (ic))->ismyparm))
continue;
/* if we are sure there are no usages */
if (bitVectIsZero (OP_USES (IC_RESULT (ic))))
{
kill = 1;
goto kill;
}
/* reset visited flag */
for (j = 0; j < count; ebbs[j++]->visited = 0);
/* find out if this definition is alive */
if (applyToSet (ebbs[i]->succList,
isDefAlive,
ic))
continue;
kill = 1;
}
kill:
/* kill this one if required */
if (kill)
{
change = 1;
gchange++;
/* eliminate this */
remiCodeFromeBBlock (ebbs[i], ic);
/* now delete from defUseSet */
deleteItemIf (&ebbs[i]->outExprs, ifDiCodeIsX, ic);
bitVectUnSetBit (ebbs[i]->outDefs, ic->key);
/* and defset of the block */
bitVectUnSetBit (ebbs[i]->defSet, ic->key);
/* for the left & right remove the usage */
if (IS_SYMOP (IC_LEFT (ic)))
bitVectUnSetBit (OP_USES (IC_LEFT (ic)), ic->key);
if (IS_SYMOP (IC_RIGHT (ic)))
bitVectUnSetBit (OP_USES (IC_RIGHT (ic)), ic->key);
}
} /* end of all instructions */
if (!ebbs[i]->sch && !ebbs[i]->noPath)
disconBBlock (ebbs[i], ebbs, count);
} /* end of for all blocks */
if (!change)
break;
} /* end of while(1) */
return gchange;
}
/*-----------------------------------------------------------------*/
static void
replaceRegEqv (eBBlock ** ebbs, int count)
{
int i;
for (i = 0; i < count; i++)
{
iCode *ic;
for (ic = ebbs[i]->sch; ic; ic = ic->next)
{
if (SKIP_IC2 (ic))
continue;
if (ic->op == IFX)
{
if (IS_TRUE_SYMOP (IC_COND (ic)) &&
OP_REQV (IC_COND (ic)))
IC_COND (ic) = opFromOpWithDU (OP_REQV (IC_COND (ic)),
OP_SYMBOL (IC_COND (ic))->defs,
OP_SYMBOL (IC_COND (ic))->uses);
continue;
}
if (ic->op == JUMPTABLE)
{
if (IS_TRUE_SYMOP (IC_JTCOND (ic)) &&
OP_REQV (IC_JTCOND (ic)))
IC_JTCOND (ic) = opFromOpWithDU (OP_REQV (IC_JTCOND (ic)),
OP_SYMBOL (IC_JTCOND (ic))->defs,
OP_SYMBOL (IC_JTCOND (ic))->uses);
continue;
}
if (ic->op == RECEIVE)
{
if (OP_SYMBOL (IC_RESULT (ic))->addrtaken)
OP_SYMBOL (IC_RESULT (ic))->isspilt = 1;
}
/* general case */
if (IC_RESULT (ic) &&
IS_TRUE_SYMOP (IC_RESULT (ic)) &&
OP_REQV (IC_RESULT (ic)))
{
if (POINTER_SET (ic))
{
IC_RESULT (ic) = opFromOpWithDU (OP_REQV (IC_RESULT (ic)),
OP_SYMBOL (IC_RESULT (ic))->defs,
OP_SYMBOL (IC_RESULT (ic))->uses);
IC_RESULT (ic)->isaddr = 1;
}
else
IC_RESULT (ic) = opFromOpWithDU (OP_REQV (IC_RESULT (ic)),
OP_SYMBOL (IC_RESULT (ic))->defs,
OP_SYMBOL (IC_RESULT (ic))->uses);
}
if (IC_RIGHT (ic) &&
IS_TRUE_SYMOP (IC_RIGHT (ic)) &&
OP_REQV (IC_RIGHT (ic)))
{
IC_RIGHT (ic) = opFromOpWithDU (OP_REQV (IC_RIGHT (ic)),
OP_SYMBOL (IC_RIGHT (ic))->defs,
OP_SYMBOL (IC_RIGHT (ic))->uses);
IC_RIGHT (ic)->isaddr = 0;
}
if (IC_LEFT (ic) &&
IS_TRUE_SYMOP (IC_LEFT (ic)) &&
OP_REQV (IC_LEFT (ic)))
{
IC_LEFT (ic) = opFromOpWithDU (OP_REQV (IC_LEFT (ic)),
OP_SYMBOL (IC_LEFT (ic))->defs,
OP_SYMBOL (IC_LEFT (ic))->uses);
IC_LEFT (ic)->isaddr = 0;
}
}
}
}
/*-----------------------------------------------------------------*/
void
separateLiveRanges (iCode *sic, ebbIndex *ebbi)
{
iCode *ic;
set *candidates = 0;
symbol *sym;
// printf("separateLiveRanges()\n");
for (ic = sic; ic; ic = ic->next)
{
if (ic->op == IFX || ic->op == GOTO || ic->op == JUMPTABLE || !IC_RESULT (ic) || !IS_ITEMP (IC_RESULT (ic)) || bitVectnBitsOn (OP_DEFS (IC_RESULT (ic))) <= 1 || isinSet (candidates, OP_SYMBOL (IC_RESULT (ic))))
continue;
addSet (&candidates, OP_SYMBOL (IC_RESULT (ic)));
}
if (!candidates)
return;
for(sym = setFirstItem (candidates); sym; sym = setNextItem (candidates))
{
// printf("Looking at %s, %d definitions\n", sym->name, bitVectnBitsOn (sym->defs));
int i;
set *defs = 0;
for (i = 0; i < sym->defs->size; i++)
if (bitVectBitValue (sym->defs, i))
{
iCode *dic;
if(dic = hTabItemWithKey (iCodehTab, i))
addSet (&defs, hTabItemWithKey (iCodehTab, i));
else
{
werror (W_INTERNAL_ERROR, __FILE__, __LINE__, "Definition not found");
return;
}
}
do
{
set *visited = 0;
set *newdefs = 0;
int oldsize;
wassert (defs);
wassert (setFirstItem (defs));
// printf("Looking at def at %d now\n", ((iCode *)(setFirstItem (defs)))->key);
if (!bitVectBitValue (((iCode *)(setFirstItem (defs)))->rlive, sym->key))
{
werror (W_INTERNAL_ERROR, __FILE__, __LINE__, "Variable is not alive at one of its definitions");
break;
}
visit (&visited, setFirstItem (defs), sym->key);
addSet (&newdefs, setFirstItem (defs));
do
{
oldsize = elementsInSet(visited);
ic = setFirstItem (defs);
for(ic = setNextItem (defs); ic; ic = setNextItem (defs))
{
// printf("Looking at other def at %d now\n", ic->key);
set *visited2 = 0;
set *intersection = 0;
visit (&visited2, ic, sym->key);
intersection = intersectSets (visited, visited2, THROW_NONE);
intersection = subtractFromSet (intersection, defs, THROW_DEST);
if (intersection)
{
visited = unionSets (visited, visited2, THROW_DEST);
addSet (&newdefs, ic);
}
deleteSet (&intersection);
deleteSet (&visited2);
}
}
while (oldsize < elementsInSet(visited));
defs = subtractFromSet (defs, newdefs, THROW_DEST);
if (newdefs && defs)
{
operand *tmpop = newiTempOperand (operandType (IC_RESULT ((iCode *)(setFirstItem (newdefs)))), TRUE);
// printf("Splitting %s from %s, using def at %d, op %d\n", OP_SYMBOL_CONST(tmpop)->name, sym->name, ((iCode *)(setFirstItem (newdefs)))->key, ((iCode *)(setFirstItem (newdefs)))->op);
for (ic = setFirstItem (visited); ic; ic = setNextItem (visited))
{
if (IC_LEFT (ic) && IS_ITEMP (IC_LEFT (ic)) && OP_SYMBOL (IC_LEFT (ic)) == sym)
IC_LEFT (ic) = operandFromOperand (tmpop);
if (IC_RIGHT (ic) && IS_ITEMP (IC_RIGHT (ic)) && OP_SYMBOL (IC_RIGHT (ic)) == sym)
IC_RIGHT (ic) = operandFromOperand (tmpop);
if (IC_RESULT (ic) && IS_ITEMP (IC_RESULT (ic)) && OP_SYMBOL (IC_RESULT (ic)) == sym && !POINTER_SET(ic) && ic->next && !isinSet (visited, ic->next))
continue;
if (IC_RESULT (ic) && IS_ITEMP (IC_RESULT (ic)) && OP_SYMBOL (IC_RESULT (ic)) == sym)
{
bool pset = POINTER_SET(ic);
IC_RESULT (ic) = operandFromOperand (tmpop);
if (pset)
IC_RESULT(ic)->isaddr = TRUE;
}
bitVectUnSetBit (sym->uses, ic->key);
}
}
deleteSet (&newdefs);
deleteSet (&visited);
}
while (elementsInSet(defs) > 1);
deleteSet (&defs);
}
deleteSet (&candidates);
}
/*-----------------------------------------------------------------*/
static int
findNextUseSym (eBBlock *ebp, iCode *ic, symbol * sym)
{
int retval = 0;
iCode *uic;
eBBlock *succ;
hTabAddItemIfNotP (&liveRanges, sym->key, sym);
if (!ic)
goto check_successors;
/* if we check a complete block and the symbol */
/* is alive at the beginning of the block */
/* and not defined in the first instructions */
/* then a next use exists (return 1) */
if ((ic == ebp->sch) && bitVectBitValue(ic->rlive, sym->key))
{
/* check if the first instruction is a def of this op */
if (ic->op == JUMPTABLE || ic->op == IFX || SKIP_IC2(ic))
return 1;
if (IS_ITEMP(IC_RESULT(ic)))
if (IC_RESULT(ic)->key == sym->key)
return 0;
return 1;
}
if (ebp->visited)
return 0;
if (ic == ebp->sch)
ebp->visited = 1;
/* for all remaining instructions in current block */
for (uic = ic; uic; uic = uic->next)
{
if (SKIP_IC2(uic))
continue;
if (uic->op == JUMPTABLE)
{
if (IS_ITEMP(IC_JTCOND(uic)) && IC_JTCOND(uic)->key == sym->key)
{
markAlive(ic, uic, sym->key);
return 1;
}
continue;
}
if (uic->op == IFX)
{
if (IS_ITEMP(IC_COND(uic)) && IC_COND(uic)->key == sym->key)
{
markAlive(ic, uic, sym->key);
return 1;
}
continue;
}
if (IS_ITEMP (IC_LEFT (uic)))
if (IC_LEFT (uic)->key == sym->key)
{
markAlive(ic, uic, sym->key);
return 1;
}
if (IS_ITEMP (IC_RIGHT (uic)))
if (IC_RIGHT (uic)->key == sym->key)
{
markAlive (ic, uic, sym->key);
return 1;
}
if (IS_ITEMP (IC_RESULT (uic)))
if (IC_RESULT (uic)->key == sym->key)
{
if (POINTER_SET (uic))
{
markAlive (ic, uic, sym->key);
return 1;
}
else
return 0;
}
}
/* check all successors */
check_successors:
succ = setFirstItem (ebp->succList);
for (; succ; succ = setNextItem (ebp->succList))
{
retval += findNextUseSym (succ, succ->sch, sym);
}
if (retval)
{
if (ic) markAlive (ic, ebp->ech, sym->key);
return 1;
}
return 0;
}
/**
Mark variables for assignment by the register allocator.
*/
static void
serialRegMark (eBBlock ** ebbs, int count)
{
int i;
short int max_alloc_bytes = SHRT_MAX; // Byte limit. Set this to a low value to pass only few variables to the register allocator. This can be useful for debugging.
stm8_call_stack_size = 2; // Saving of register to stack temporarily.
/* for all blocks */
for (i = 0; i < count; i++)
{
iCode *ic;
if (ebbs[i]->noPath && (ebbs[i]->entryLabel != entryLabel && ebbs[i]->entryLabel != returnLabel))
continue;
/* for all instructions do */
for (ic = ebbs[i]->sch; ic; ic = ic->next)
{
if ((ic->op == CALL || ic->op == PCALL) && ic->parmBytes + 5 > stm8_call_stack_size)
{
sym_link *dtype = operandType (IC_LEFT (ic));
sym_link *ftype = IS_FUNCPTR (dtype) ? dtype->next : dtype;
/* 5 for saving all registers at call site + 2 for big return value */
stm8_call_stack_size = ic->parmBytes + 5 + 2 * (getSize (ftype->next) > 4);
}
if (ic->op == IPOP)
wassert (0);
/* if result is present && is a true symbol */
if (IC_RESULT (ic) && ic->op != IFX && IS_TRUE_SYMOP (IC_RESULT (ic)))
OP_SYMBOL (IC_RESULT (ic))->allocreq++;
/* some don't need registers, since there is no result. */
if (SKIP_IC2 (ic) ||
ic->op == JUMPTABLE || ic->op == IFX || ic->op == IPUSH || ic->op == IPOP || (IC_RESULT (ic) && POINTER_SET (ic)))
continue;
/* now we need to allocate registers only for the result */
if (IC_RESULT (ic))
{
symbol *sym = OP_SYMBOL (IC_RESULT (ic));
D (D_ALLOC, ("serialRegAssign: in loop on result %p\n", sym));
if (sym->isspilt && sym->usl.spillLoc) // todo: Remove once remat is supported!
{
sym->usl.spillLoc->allocreq--;
sym->isspilt = FALSE;
}
/* Make sure any spill location is definately allocated */
if (sym->isspilt && !sym->remat && sym->usl.spillLoc && !sym->usl.spillLoc->allocreq)
sym->usl.spillLoc->allocreq++;
/* if it does not need or is spilt
or is already marked for the new allocator
or will not live beyond this instructions */
if (!sym->nRegs ||
sym->isspilt || sym->for_newralloc || sym->liveTo <= ic->seq)
{
D (D_ALLOC, ("serialRegAssign: won't live long enough.\n"));
continue;
}
if (sym->nRegs > 4 && ic->op == CALL)
{
spillThis (sym, TRUE);
}
else if (max_alloc_bytes >= sym->nRegs)
{
sym->for_newralloc = 1;
max_alloc_bytes -= sym->nRegs;
}
else if (!sym->for_newralloc)
{
spillThis (sym, TRUE);
printf ("Spilt %s due to byte limit.\n", sym->name);
}
}
}
}
}
/** Register reduction for assignment.
*/
static int
packRegsForAssign (iCode *ic, eBBlock *ebp)
{
iCode *dic, *sic;
if (!IS_ITEMP (IC_RIGHT (ic)) || OP_SYMBOL (IC_RIGHT (ic))->isind || OP_LIVETO (IC_RIGHT (ic)) > ic->seq)
return 0;
/* Avoid having multiple named address spaces in one iCode. */
if (IS_SYMOP (IC_RESULT (ic)) && SPEC_ADDRSPACE (OP_SYMBOL (IC_RESULT (ic))->etype))
return 0;
/* find the definition of iTempNN scanning backwards if we find a
a use of the true symbol in before we find the definition then
we cannot */
for (dic = ic->prev; dic; dic = dic->prev)
{
/* PENDING: Don't pack across function calls. */
if (dic->op == CALL || dic->op == PCALL)
{
dic = NULL;
break;
}
if (SKIP_IC2 (dic))
continue;
if (dic->op == IFX)
{
if (IS_SYMOP (IC_COND (dic)) &&
(IC_COND (dic)->key == IC_RESULT (ic)->key || IC_COND (dic)->key == IC_RIGHT (ic)->key))
{
dic = NULL;
break;
}
}
else
{
if (IS_TRUE_SYMOP (IC_RESULT (dic)) && IS_OP_VOLATILE (IC_RESULT (dic)))
{
dic = NULL;
break;
}
if (IS_SYMOP (IC_RESULT (dic)) && IC_RESULT (dic)->key == IC_RIGHT (ic)->key)
{
if (POINTER_SET (dic))
dic = NULL;
break;
}
if (IS_SYMOP (IC_RIGHT (dic)) &&
(IC_RIGHT (dic)->key == IC_RESULT (ic)->key || IC_RIGHT (dic)->key == IC_RIGHT (ic)->key))
{
dic = NULL;
break;
}
if (IS_SYMOP (IC_LEFT (dic)) &&
(IC_LEFT (dic)->key == IC_RESULT (ic)->key || IC_LEFT (dic)->key == IC_RIGHT (ic)->key))
{
dic = NULL;
break;
}
if (IS_SYMOP (IC_RESULT (dic)) && IC_RESULT (dic)->key == IC_RESULT (ic)->key)
{
dic = NULL;
break;
}
}
}
if (!dic)
return 0; /* did not find */
/* if assignment then check that right is not a bit */
if (ASSIGNMENT (ic) && !POINTER_SET (ic))
{
sym_link *etype = operandType (IC_RESULT (dic));
if (IS_BITFIELD (etype))
{
/* if result is a bit too then it's ok */
etype = operandType (IC_RESULT (ic));
if (!IS_BITFIELD (etype))
{
return 0;
}
}
}
/* if the result is on stack or iaccess then it must be
the same atleast one of the operands */
if (OP_SYMBOL (IC_RESULT (ic))->onStack || OP_SYMBOL (IC_RESULT (ic))->iaccess)
{
/* the operation has only one symbol
operator then we can pack */
if ((IC_LEFT (dic) && !IS_SYMOP (IC_LEFT (dic))) || (IC_RIGHT (dic) && !IS_SYMOP (IC_RIGHT (dic))))
goto pack;
if (!((IC_LEFT (dic) &&
IC_RESULT (ic)->key == IC_LEFT (dic)->key) || (IC_RIGHT (dic) && IC_RESULT (ic)->key == IC_RIGHT (dic)->key)))
return 0;
}
pack:
/* found the definition */
/* replace the result with the result of */
/* this assignment and remove this assignment */
bitVectUnSetBit (OP_SYMBOL (IC_RESULT (dic))->defs, dic->key);
IC_RESULT (dic) = IC_RESULT (ic);
if (IS_ITEMP (IC_RESULT (dic)) && OP_SYMBOL (IC_RESULT (dic))->liveFrom > dic->seq)
{
OP_SYMBOL (IC_RESULT (dic))->liveFrom = dic->seq;
}
/* delete from liverange table also
delete from all the points inbetween and the new
one */
for (sic = dic; sic != ic; sic = sic->next)
{
bitVectUnSetBit (sic->rlive, IC_RESULT (ic)->key);
if (IS_ITEMP (IC_RESULT (dic)))
bitVectSetBit (sic->rlive, IC_RESULT (dic)->key);
}
remiCodeFromeBBlock (ebp, ic);
// PENDING: Check vs mcs51
bitVectUnSetBit (OP_SYMBOL (IC_RESULT (ic))->defs, ic->key);
hTabDeleteItem (&iCodehTab, ic->key, ic, DELETE_ITEM, NULL);
OP_DEFS (IC_RESULT (dic)) = bitVectSetBit (OP_DEFS (IC_RESULT (dic)), dic->key);
return 1;
}
/*-----------------------------------------------------------------*/
static void
rlivePoint (eBBlock ** ebbs, int count, bool emitWarnings)
{
int i, key;
eBBlock *succ;
bitVect *alive;
/* for all blocks do */
for (i = 0; i < count; i++)
{
iCode *ic;
/* for all instructions in this block do */
for (ic = ebbs[i]->sch; ic; ic = ic->next)
{
if (!ic->rlive)
ic->rlive = newBitVect (operandKey);
if (SKIP_IC2(ic))
continue;
if (ic->op == JUMPTABLE && IS_SYMOP(IC_JTCOND(ic)))
{
incUsed (ic, IC_JTCOND(ic));
if (!IS_AUTOSYM(IC_JTCOND(ic)))
continue;
findPrevUse (ebbs[i], ic, IC_JTCOND(ic), ebbs, count, emitWarnings);
if (IS_ITEMP(IC_JTCOND(ic)))
{
unvisitBlocks(ebbs, count);
ic->rlive = bitVectSetBit (ic->rlive, IC_JTCOND(ic)->key);
findNextUse (ebbs[i], ic->next, IC_JTCOND(ic));
}
continue;
}
if (ic->op == IFX && IS_SYMOP(IC_COND(ic)))
{
incUsed (ic, IC_COND(ic));
if (!IS_AUTOSYM(IC_COND(ic)))
continue;
findPrevUse (ebbs[i], ic, IC_COND(ic), ebbs, count, emitWarnings);
if (IS_ITEMP(IC_COND(ic)))
{
unvisitBlocks (ebbs, count);
ic->rlive = bitVectSetBit (ic->rlive, IC_COND(ic)->key);
findNextUse (ebbs[i], ic->next, IC_COND(ic));
}
continue;
}
if (IS_SYMOP(IC_LEFT(ic)))
{
incUsed (ic, IC_LEFT(ic));
if (IS_AUTOSYM(IC_LEFT(ic)) &&
ic->op != ADDRESS_OF)
{
findPrevUse (ebbs[i], ic, IC_LEFT(ic), ebbs, count, emitWarnings);
if (IS_ITEMP(IC_LEFT(ic)))
{
unvisitBlocks(ebbs, count);
ic->rlive = bitVectSetBit (ic->rlive, IC_LEFT(ic)->key);
findNextUse (ebbs[i], ic->next, IC_LEFT(ic));
/* if this is a send extend the LR to the call */
if (ic->op == SEND)
{
iCode *lic;
for (lic = ic; lic; lic = lic->next)
{
if (lic->op == CALL || lic->op == PCALL)
{
markAlive (ic, lic->prev, IC_LEFT (ic)->key);
break;
}
}
}
}
}
}
if (IS_SYMOP(IC_RIGHT(ic)))
{
incUsed (ic, IC_RIGHT(ic));
if (IS_AUTOSYM(IC_RIGHT(ic)))
{
findPrevUse (ebbs[i], ic, IC_RIGHT(ic), ebbs, count, emitWarnings);
if (IS_ITEMP(IC_RIGHT(ic)))
{
unvisitBlocks(ebbs, count);
ic->rlive = bitVectSetBit (ic->rlive, IC_RIGHT(ic)->key);
findNextUse (ebbs[i], ic->next, IC_RIGHT(ic));
}
}
}
if (POINTER_SET(ic) && IS_SYMOP(IC_RESULT(ic)))
incUsed (ic, IC_RESULT(ic));
if (IS_AUTOSYM(IC_RESULT(ic)))
{
if (POINTER_SET(ic))
{
findPrevUse (ebbs[i], ic, IC_RESULT(ic), ebbs, count, emitWarnings);
}
if (IS_ITEMP(IC_RESULT(ic)))
{
unvisitBlocks(ebbs, count);
ic->rlive = bitVectSetBit (ic->rlive, IC_RESULT(ic)->key);
findNextUse (ebbs[i], ic->next, IC_RESULT(ic));
/* findNextUse sometimes returns 0 here, which means that ic is
dead code. Something should be done about this dead code since
e.g. register allocation suffers. */
}
}
if (!POINTER_SET(ic) && IC_RESULT(ic))
ic->defKey = IC_RESULT(ic)->key;
}
/* check all symbols that are alive in the last instruction */
/* but are not alive in all successors */
succ = setFirstItem (ebbs[i]->succList);
if (!succ)
continue;
alive = succ->sch->rlive;
while ((succ = setNextItem (ebbs[i]->succList)))
{
if (succ->sch)
alive = bitVectIntersect (alive, succ->sch->rlive);
}
if (ebbs[i]->ech)
alive = bitVectCplAnd ( bitVectCopy (ebbs[i]->ech->rlive), alive);
if(!alive)
continue;
for (key = 1; key < alive->size; key++)
{
if (!bitVectBitValue (alive, key))
continue;
unvisitBlocks(ebbs, count);
findNextUseSym (ebbs[i], NULL, hTabItemWithKey (liveRanges, key));
}
}
}
/*--------------------------------------------------------------------*/
int
ptrPseudoSymSafe (symbol *sym, iCode *dic)
{
symbol * ptrsym;
symbol * basesym;
iCode * ric;
iCode * ic;
int ptrsymDclType;
//int isGlobal;
assert(POINTER_GET (dic));
/* Can't if spills to this symbol are prohibited */
if (sym->noSpilLoc)
return 0;
/* Get the pointer */
if (!IS_SYMOP (IC_LEFT (dic)))
return 0;
ptrsym = OP_SYMBOL (IC_LEFT (dic));
/* Must be a rematerializable pointer */
if (!ptrsym->remat)
return 0;
/* The pointer type must be uncasted */
if (IS_CAST_ICODE (ptrsym->rematiCode))
return 0;
/* The symbol's live range must not preceed its definition */
if (dic->seq > sym->liveFrom)
return 0;
/* Ok, this is a good candidate for a pseudo symbol. */
/* However, we must check for two hazards: */
/* 1) The symbol's live range must not include a CALL */
/* or PCALL iCode. */
/* 2) The symbol's live range must not include any */
/* writes to the variable the pointer rematerializes */
/* within (to avoid aliasing problems) */
/* Find the base symbol the rematerialization is based on */
ric = ptrsym->rematiCode;
while (ric->op == '+' || ric->op == '-')
ric = OP_SYMBOL (IC_LEFT (ric))->rematiCode;
if (IS_CAST_ICODE(ric))
return 0;
basesym = OP_SYMBOL (IC_LEFT (ric));
//isGlobal = !basesym->islocal && !basesym->ismyparm;
ptrsymDclType = aggrToPtrDclType (ptrsym->type, FALSE);
ic = dic->next;
while (ic && ic->seq <= sym->liveTo)
{
if (!(SKIP_IC3 (ic) || ic->op == IFX))
{
/* Check for hazard #1 */
if ((ic->op == CALL || ic->op == PCALL) /* && isGlobal */ )
{
if (ic->seq <= sym->liveTo)
return 0;
}
/* Check for hazard #2 */
else if (POINTER_SET (ic))
{
symbol * ptrsym2 = OP_SYMBOL (IC_RESULT (ic));
if (ptrsym2->remat)
{
/* Must not be the same base symbol */
if (basesym == ptrBaseRematSym (ptrsym2))
return 0;
}
else
{
int ptrsym2DclType = aggrToPtrDclType (ptrsym2->type, FALSE);
/* Pointer must have no memory space in common */
if (ptrsym2DclType == ptrsymDclType
|| ptrsym2DclType == GPOINTER
|| ptrsymDclType == GPOINTER)
return 0;
}
}
else if (IC_RESULT (ic))
{
symbol * rsym = OP_SYMBOL (IC_RESULT (ic));
/* Make sure there is no conflict with another pseudo symbol */
if (rsym->psbase == basesym)
return 0;
if (rsym->isspilt && rsym->usl.spillLoc)
rsym = rsym->usl.spillLoc;
if (rsym->psbase == basesym)
return 0;
}
}
if (ic->seq == sym->liveTo)
break;
ic = ic->next;
}
/* If the live range went past the end of the defining basic */
/* block, then a full analysis is too complicated to attempt */
/* here. To be safe, we must assume the worst. */
if (!ic)
return 0;
/* Ok, looks safe */
return 1;
}