bool
PrintPass::visit(BasicBlock *bb)
{
#if 0
INFO("---\n");
for (Graph::EdgeIterator ei = bb->cfg.incident(); !ei.end(); ei.next())
INFO(" <- BB:%i (%s)\n",
BasicBlock::get(ei.getNode())->getId(),
ei.getEdge()->typeStr());
#endif
INFO("BB:%i (%u instructions) - ", bb->getId(), bb->getInsnCount());
if (bb->idom())
INFO("idom = BB:%i, ", bb->idom()->getId());
INFO("df = { ");
for (DLList::Iterator df = bb->getDF().iterator(); !df.end(); df.next())
INFO("BB:%i ", BasicBlock::get(df)->getId());
INFO("}\n");
for (Graph::EdgeIterator ei = bb->cfg.outgoing(); !ei.end(); ei.next())
INFO(" -> BB:%i (%s)\n",
BasicBlock::get(ei.getNode())->getId(),
ei.getEdge()->typeStr());
return true;
}
unsigned int
BasicBlock::initiatesSimpleConditional() const
{
Graph::Node *out[2];
int n;
Graph::Edge::Type eR;
if (cfg.outgoingCount() != 2) // -> if and -> else/endif
return false;
n = 0;
for (Graph::EdgeIterator ei = cfg.outgoing(); !ei.end(); ei.next())
out[n++] = ei.getNode();
eR = out[1]->outgoing().getType();
// IF block is out edge to the right
if (eR == Graph::Edge::CROSS || eR == Graph::Edge::BACK)
return 0x2;
if (out[1]->outgoingCount() != 1) // 0 is IF { RET; }, >1 is more divergence
return 0x0;
// do they reconverge immediately ?
if (out[1]->outgoing().getNode() == out[0])
return 0x1;
if (out[0]->outgoingCount() == 1)
if (out[0]->outgoing().getNode() == out[1]->outgoing().getNode())
return 0x3;
return 0x0;
}
void DominatorTree::buildDFS(Graph::Node *node)
{
SEMI(node->tag) = node->tag;
for (Graph::EdgeIterator ei = node->outgoing(); !ei.end(); ei.next()) {
if (SEMI(ei.getNode()->tag) < 0) {
buildDFS(ei.getNode());
PARENT(ei.getNode()->tag) = node->tag;
}
}
}
void search(Graph::Node *node, const bool preorder, const int sequence)
{
if (preorder)
nodes[count++] = node;
for (Graph::EdgeIterator ei = node->outgoing(); !ei.end(); ei.next())
if (ei.getNode()->visit(sequence))
search(ei.getNode(), preorder, sequence);
if (!preorder)
nodes[count++] = node;
}
void DominatorTree::build()
{
DLList *bucket = new DLList[count];
Node *nv, *nw;
int p, u, v, w;
buildDFS(cfg->getRoot());
for (w = count - 1; w >= 1; --w) {
nw = vert[w];
assert(nw->tag == w);
for (Graph::EdgeIterator ei = nw->incident(); !ei.end(); ei.next()) {
nv = ei.getNode();
v = nv->tag;
u = eval(v);
if (SEMI(u) < SEMI(w))
SEMI(w) = SEMI(u);
}
p = PARENT(w);
bucket[SEMI(w)].insert(nw);
link(p, w);
for (DLList::Iterator it = bucket[p].iterator(); !it.end(); it.erase()) {
v = reinterpret_cast<Node *>(it.get())->tag;
u = eval(v);
DOM(v) = (SEMI(u) < SEMI(v)) ? u : p;
}
}
for (w = 1; w < count; ++w) {
if (DOM(w) != SEMI(w))
DOM(w) = DOM(DOM(w));
}
DOM(0) = 0;
insert(&BasicBlock::get(cfg->getRoot())->dom);
do {
p = 0;
for (v = 1; v < count; ++v) {
nw = &BasicBlock::get(vert[DOM(v)])->dom;;
nv = &BasicBlock::get(vert[v])->dom;
if (nw->getGraph() && !nv->getGraph()) {
++p;
nw->attach(nv, Graph::Edge::TREE);
}
}
} while (p);
delete[] bucket;
}
// liveIn(bb) = usedBeforeAssigned(bb) U (liveOut(bb) - assigned(bb))
void
Function::buildLiveSetsPreSSA(BasicBlock *bb, const int seq)
{
Function *f = bb->getFunction();
BitSet usedBeforeAssigned(allLValues.getSize(), true);
BitSet assigned(allLValues.getSize(), true);
bb->liveSet.allocate(allLValues.getSize(), false);
int n = 0;
for (Graph::EdgeIterator ei = bb->cfg.outgoing(); !ei.end(); ei.next()) {
BasicBlock *out = BasicBlock::get(ei.getNode());
if (out == bb)
continue;
if (out->cfg.visit(seq))
buildLiveSetsPreSSA(out, seq);
if (!n++)
bb->liveSet = out->liveSet;
else
bb->liveSet |= out->liveSet;
}
if (!n && !bb->liveSet.marker)
bb->liveSet.fill(0);
bb->liveSet.marker = true;
for (Instruction *i = bb->getEntry(); i; i = i->next) {
for (int s = 0; i->srcExists(s); ++s)
if (i->getSrc(s)->asLValue() && !assigned.test(i->getSrc(s)->id))
usedBeforeAssigned.set(i->getSrc(s)->id);
for (int d = 0; i->defExists(d); ++d)
assigned.set(i->getDef(d)->id);
}
if (bb == BasicBlock::get(f->cfgExit)) {
for (std::deque<ValueRef>::iterator it = f->outs.begin();
it != f->outs.end(); ++it) {
if (!assigned.test(it->get()->id))
usedBeforeAssigned.set(it->get()->id);
}
}
bb->liveSet.andNot(assigned);
bb->liveSet |= usedBeforeAssigned;
}
void
Function::printCFGraph(const char *filePath)
{
FILE *out = fopen(filePath, "a");
if (!out) {
ERROR("failed to open file: %s\n", filePath);
return;
}
INFO("printing control flow graph to: %s\n", filePath);
fprintf(out, "digraph G {\n");
for (IteratorRef it = cfg.iteratorDFS(); !it->end(); it->next()) {
BasicBlock *bb = BasicBlock::get(
reinterpret_cast<Graph::Node *>(it->get()));
int idA = bb->getId();
for (Graph::EdgeIterator ei = bb->cfg.outgoing(); !ei.end(); ei.next()) {
int idB = BasicBlock::get(ei.getNode())->getId();
switch (ei.getType()) {
case Graph::Edge::TREE:
fprintf(out, "\t%i -> %i;\n", idA, idB);
break;
case Graph::Edge::FORWARD:
fprintf(out, "\t%i -> %i [color=green];\n", idA, idB);
break;
case Graph::Edge::CROSS:
fprintf(out, "\t%i -> %i [color=red];\n", idA, idB);
break;
case Graph::Edge::BACK:
fprintf(out, "\t%i -> %i;\n", idA, idB);
break;
case Graph::Edge::DUMMY:
fprintf(out, "\t%i -> %i [style=dotted];\n", idA, idB);
break;
default:
assert(0);
break;
}
}
}
fprintf(out, "}\n");
fclose(out);
}
BasicBlock *
BasicBlock::clone(ClonePolicy<Function>& pol) const
{
BasicBlock *bb = new BasicBlock(pol.context());
pol.set(this, bb);
for (Instruction *i = getFirst(); i; i = i->next)
bb->insertTail(i->clone(pol));
pol.context()->cfg.insert(&bb->cfg);
for (Graph::EdgeIterator it = cfg.outgoing(); !it.end(); it.next()) {
BasicBlock *obb = BasicBlock::get(it.getNode());
bb->cfg.attach(&pol.get(obb)->cfg, it.getType());
}
return bb;
}
void
Function::buildDefSetsPreSSA(BasicBlock *bb, const int seq)
{
bb->defSet.allocate(allLValues.getSize(), !bb->liveSet.marker);
bb->liveSet.marker = true;
for (Graph::EdgeIterator ei = bb->cfg.incident(); !ei.end(); ei.next()) {
BasicBlock *in = BasicBlock::get(ei.getNode());
if (in->cfg.visit(seq))
buildDefSetsPreSSA(in, seq);
bb->defSet |= in->defSet;
}
for (Instruction *i = bb->getEntry(); i; i = i->next) {
for (int d = 0; i->defExists(d); ++d)
bb->defSet.set(i->getDef(d)->id);
}
}
void search(Graph::Node *node, const int sequence)
{
Stack bb, cross;
bb.push(node);
while (bb.getSize()) {
node = reinterpret_cast<Graph::Node *>(bb.pop().u.p);
assert(node);
if (!node->visit(sequence))
continue;
node->tag = 0;
for (Graph::EdgeIterator ei = node->outgoing(); !ei.end(); ei.next()) {
switch (ei.getType()) {
case Graph::Edge::TREE:
case Graph::Edge::FORWARD:
case Graph::Edge::DUMMY:
if (++(ei.getNode()->tag) == ei.getNode()->incidentCountFwd())
bb.push(ei.getNode());
break;
case Graph::Edge::BACK:
continue;
case Graph::Edge::CROSS:
if (++(ei.getNode()->tag) == 1)
cross.push(ei.getNode());
break;
default:
assert(!"unknown edge kind in CFG");
break;
}
}
nodes[count++] = node;
if (bb.getSize() == 0)
cross.moveTo(bb);
}
}
// Go through BBs in dominance order, create new values for each definition,
// and replace all sources with their current new values.
//
// NOTE: The values generated for function inputs/outputs have no connection
// to their corresponding outputs/inputs in other functions. Only allocation
// of physical registers will establish this connection.
//
void RenamePass::search(BasicBlock *bb)
{
LValue *lval, *ssa;
int d, s;
const Target *targ = prog->getTarget();
// Put current definitions for function inputs values on the stack.
// They can be used before any redefinitions are pushed.
if (bb == BasicBlock::get(func->cfg.getRoot())) {
for (std::deque<ValueDef>::iterator it = func->ins.begin();
it != func->ins.end(); ++it) {
lval = it->get()->asLValue();
assert(lval);
ssa = new_LValue(func, targ->nativeFile(lval->reg.file));
ssa->reg.size = lval->reg.size;
ssa->reg.data.id = lval->reg.data.id;
it->setSSA(ssa);
stack[lval->id].push(ssa);
}
}
for (Instruction *stmt = bb->getFirst(); stmt; stmt = stmt->next) {
// PHI sources get definitions from the passes through the incident BBs,
// so skip them here.
if (stmt->op != OP_PHI) {
for (s = 0; stmt->srcExists(s); ++s) {
lval = stmt->getSrc(s)->asLValue();
if (!lval)
continue;
// Values on the stack created in previously visited blocks, and
// function inputs, will be valid because they dominate this one.
lval = getStackTop(lval);
if (!lval)
lval = mkUndefined(stmt->getSrc(s));
stmt->setSrc(s, lval);
}
}
for (d = 0; stmt->defExists(d); ++d) {
lval = stmt->def(d).get()->asLValue();
assert(lval);
stmt->def(d).setSSA(
new_LValue(func, targ->nativeFile(lval->reg.file)));
stmt->def(d).get()->reg.size = lval->reg.size;
stmt->def(d).get()->reg.data.id = lval->reg.data.id;
stack[lval->id].push(stmt->def(d).get());
}
}
// Update sources of PHI ops corresponding to this BB in outgoing BBs.
for (Graph::EdgeIterator ei = bb->cfg.outgoing(); !ei.end(); ei.next()) {
Instruction *phi;
int p = 0;
BasicBlock *sb = BasicBlock::get(ei.getNode());
// which predecessor of sb is bb ?
for (Graph::EdgeIterator ei = sb->cfg.incident(); !ei.end(); ei.next()) {
if (ei.getNode() == &bb->cfg)
break;
++p;
}
assert(p < sb->cfg.incidentCount());
for (phi = sb->getPhi(); phi && phi->op == OP_PHI; phi = phi->next) {
lval = getStackTop(phi->getSrc(p));
if (!lval)
lval = mkUndefined(phi->getSrc(p));
phi->setSrc(p, lval);
}
}
// Visit the BBs we dominate.
for (Graph::EdgeIterator ei = bb->dom.outgoing(); !ei.end(); ei.next())
search(BasicBlock::get(ei.getNode()));
// Update function outputs to the last definitions of their pre-SSA values.
// I hope they're unique, i.e. that we get PHIs for all of them ...
if (bb == BasicBlock::get(func->cfgExit)) {
for (std::deque<ValueRef>::iterator it = func->outs.begin();
it != func->outs.end(); ++it) {
lval = it->get()->asLValue();
if (!lval)
continue;
lval = getStackTop(lval);
if (!lval)
lval = mkUndefined(it->get());
it->set(lval);
}
}
// Pop the values we created in this block from the stack because we will
// return to blocks that we do not dominate.
for (Instruction *stmt = bb->getFirst(); stmt; stmt = stmt->next) {
if (stmt->op == OP_NOP)
continue;
for (d = 0; stmt->defExists(d); ++d)
stack[stmt->def(d).preSSA()->id].pop();
}
}