llvm-objdump: factor code better, add comments.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@140153 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/llvm-objdump/MCFunction.cpp b/tools/llvm-objdump/MCFunction.cpp
index 03390c2..5c67f1b 100644
--- a/tools/llvm-objdump/MCFunction.cpp
+++ b/tools/llvm-objdump/MCFunction.cpp
@@ -47,44 +47,39 @@
while (!WorkList.empty()) {
uint64_t Index = WorkList.pop_back_val();
if (VisitedInsts.find(Index) != VisitedInsts.end())
- continue;
+ continue; // Already visited this location.
for (;Index < End; Index += Size) {
- MCInst Inst;
+ VisitedInsts.insert(Index);
+ MCInst Inst;
if (DisAsm->getInstruction(Inst, Size, Region, Index, DebugOut, nulls())){
+ Instructions.push_back(MCDecodedInst(Index, Size, Inst));
if (Ana->isBranch(Inst)) {
uint64_t targ = Ana->evaluateBranch(Inst, Index, Size);
- if (targ != -1ULL && targ == Index+Size) {
- Instructions.push_back(MCDecodedInst(Index, Size, Inst));
- VisitedInsts.insert(Index);
- continue;
- }
+ if (targ != -1ULL && targ == Index+Size)
+ continue; // Skip nop jumps.
+
+ // If we could determine the branch target, make a note to start a
+ // new basic block there and add the target to the worklist.
if (targ != -1ULL) {
Splits.insert(targ);
WorkList.push_back(targ);
WorkList.push_back(Index+Size);
}
Splits.insert(Index+Size);
- Instructions.push_back(MCDecodedInst(Index, Size, Inst));
- VisitedInsts.insert(Index);
break;
} else if (Ana->isReturn(Inst)) {
+ // Return instruction. This basic block ends here.
Splits.insert(Index+Size);
- Instructions.push_back(MCDecodedInst(Index, Size, Inst));
- VisitedInsts.insert(Index);
break;
} else if (Ana->isCall(Inst)) {
uint64_t targ = Ana->evaluateBranch(Inst, Index, Size);
- if (targ != -1ULL && targ != Index+Size) {
+ // Add the call to the call list if the destination is known.
+ if (targ != -1ULL && targ != Index+Size)
Calls.push_back(targ);
- }
}
-
- Instructions.push_back(MCDecodedInst(Index, Size, Inst));
- VisitedInsts.insert(Index);
} else {
- VisitedInsts.insert(Index);
errs().write_hex(Index) << ": warning: invalid instruction encoding\n";
if (Size == 0)
Size = 1; // skip illegible bytes
@@ -93,9 +88,10 @@
}
}
+ // Make sure the instruction list is sorted.
std::sort(Instructions.begin(), Instructions.end());
- // Create basic blocks.
+ // Create basic blocks.
unsigned ii = 0, ie = Instructions.size();
for (std::set<uint64_t>::iterator spi = Splits.begin(),
spe = llvm::prior(Splits.end()); spi != spe; ++spi) {
@@ -115,7 +111,7 @@
// Calculate successors of each block.
for (MCFunction::iterator i = f.begin(), e = f.end(); i != e; ++i) {
- MCBasicBlock &BB = i->second;
+ MCBasicBlock &BB = const_cast<MCBasicBlock&>(i->second);
if (BB.getInsts().empty()) continue;
const MCDecodedInst &Inst = BB.getInsts().back();