private LGraph buildBlocks() throws Exception {
lir_.entry = new LBlock(lir_.entry_pc);
BlockBuilder builder = new BlockBuilder(lir_);
LBlock entry = builder.parse();
// Get an RPO ordering of the blocks, since we don't have predecessors yet.
LBlock[] blocks = BlockAnalysis.Order(entry);
// Remove dead references.
// Ignore blocks that are unreachable and are always jumped over
// e.g.
// if(1 != 1)
// loop()..
for (LBlock block : blocks) {
int numPredecessors = block.numPredecessors();
for (int i = 0; i < numPredecessors; i++) {
if (!ContainsBlock(blocks, block.getPredecessor(i))) {
block.removePredecessor(block.getPredecessor(i));
numPredecessors--;
}
}
}
if (!BlockAnalysis.IsReducible(blocks))
throw new Exception("control flow graph is not reducible");
// Split critical edges in the graph (is this even needed?)
BlockAnalysis.SplitCriticalEdges(blocks);
// Reorder the blocks since we could have introduced new nodes.
blocks = BlockAnalysis.Order(entry);
assert (BlockAnalysis.IsReducible(blocks));
BlockAnalysis.ComputeDominators(blocks);
BlockAnalysis.ComputeImmediateDominators(blocks);
BlockAnalysis.ComputeDominatorTree(blocks);
BlockAnalysis.FindLoops(blocks);
LGraph graph = new LGraph();
graph.blocks = blocks;
graph.entry = blocks[0];
if (lir_.argDepth > 0) graph.nargs = ((lir_.argDepth - 12) / 4) + 1;
else graph.nargs = 0;
return graph;
}
