/**
* Create the edges in the control flow graph with the basic blocks.
*
* @param insts the instructions
* @param numBlocks an array containing the number of basic block for each instruction.
* @param bbs the basic blocks
*/
private void findCFGEdges(Instruction[] insts, short[] numBlocks, BasicBlock[] bbs) {
for (int i = 0; i < bbs.length; ++i) {
BasicBlock bb = bbs[i];
Instruction lastInst = insts[bb.getEnd()];
if (lastInst.canComplete() && i != bbs.length - 1) {
// the next block is accessible
bb.addDefaultNextBlock(bbs[i + 1]);
}
if (lastInst instanceof JumpInstruction) {
// goto, jsr are distincts than other jump instructions.
Edge edge;
JumpInstruction jumpInst = (JumpInstruction) lastInst;
if (lastInst.getOpcode() == ClassfileConstants2.opc_goto) {
edge =
bb.addDefaultNextBlock(
bbs[numBlocks[getInstructionLine(insts, jumpInst.getTarget())]]);
jumpInst.setTarget(new EdgeLabel(edge));
} else if (lastInst.getOpcode() == ClassfileConstants2.opc_jsr) {
// do nothing here
// see method findSubRoutines
} else {
edge =
bb.addConditionNextBlock(
bbs[numBlocks[getInstructionLine(insts, jumpInst.getTarget())]]);
jumpInst.setTarget(new EdgeLabel(edge));
}
}
if (lastInst instanceof SwitchInstruction) {
SwitchInstruction si = (SwitchInstruction) lastInst;
for (int k = -1; k < si.getSwitchCount(); k++) {
Edge edge =
bb.addSwitchNextBlock(bbs[numBlocks[getInstructionLine(insts, si.getTarget(k))]]);
si.setTarget(k, new EdgeLabel(edge));
}
}
}
}
