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MC CFG: When disassembly is impossible, fallback to data bytes. 

This is the behavior of sequential disassemblers (llvm-objdump, ...),
when there is no instruction size hint (fixed-length, ...)

While there, also do some minor cleanup.

llvm-svn: 188883
This commit is contained in:
Ahmed Bougacha 2013-08-21 07:28:32 +00:00
parent a376353346
commit 57bc9677cd
1 changed files with 30 additions and 16 deletions
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46
llvm/lib/MC/MCObjectDisassembler.cpp
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@ -102,19 +102,29 @@ void MCObjectDisassembler::buildSectionAtoms(MCModule *Module) {
StringRef SecName; SI->getName(SecName); StringRef SecName; SI->getName(SecName);
if (isText) { if (isText) {
MCTextAtom *Text = Module->createTextAtom(StartAddr, EndAddr); MCTextAtom *Text = 0;
Text->setName(SecName); MCDataAtom *InvalidData = 0;
uint64_t InstSize; uint64_t InstSize;
for (uint64_t Index = 0; Index < SecSize; Index += InstSize) { for (uint64_t Index = 0; Index < SecSize; Index += InstSize) {
const uint64_t CurAddr = StartAddr + Index;
MCInst Inst; MCInst Inst;
if (Dis.getInstruction(Inst, InstSize, memoryObject, Index, if (Dis.getInstruction(Inst, InstSize, memoryObject, CurAddr, nulls(),
nulls(), nulls())) nulls())) {
if (!Text) {
Text = Module->createTextAtom(CurAddr, CurAddr);
Text->setName(SecName);
}
Text->addInst(Inst, InstSize); Text->addInst(Inst, InstSize);
else InvalidData = 0;
// We don't care about splitting mixed atoms either. } else {
llvm_unreachable("Couldn't disassemble instruction in atom."); if (!InvalidData) {
Text = 0;
InvalidData = Module->createDataAtom(CurAddr, EndAddr);
}
InvalidData->addData(Contents[Index]);
}
} }
} else { } else {
MCDataAtom *Data = Module->createDataAtom(StartAddr, EndAddr); MCDataAtom *Data = Module->createDataAtom(StartAddr, EndAddr);
Data->setName(SecName); Data->setName(SecName);
@ -134,6 +144,8 @@ namespace {
BBInfoSetTy Succs; BBInfoSetTy Succs;
BBInfoSetTy Preds; BBInfoSetTy Preds;
BBInfo() : Atom(0), BB(0) {}
void addSucc(BBInfo &Succ) { void addSucc(BBInfo &Succ) {
Succs.insert(&Succ); Succs.insert(&Succ);
Succ.Preds.insert(this); Succ.Preds.insert(this);
@ -232,8 +244,8 @@ void MCObjectDisassembler::buildCFG(MCModule *Module) {
// Create MCBBs. // Create MCBBs.
SmallSetVector<BBInfo*, 16> Worklist; SmallSetVector<BBInfo*, 16> Worklist;
Worklist.insert(&BBI); Worklist.insert(&BBI);
for (size_t WI = 0; WI < Worklist.size(); ++WI) { for (size_t wi = 0; wi < Worklist.size(); ++wi) {
BBInfo *BBI = Worklist[WI]; BBInfo *BBI = Worklist[wi];
if (!BBI->Atom) if (!BBI->Atom)
continue; continue;
BBI->BB = &MCFN.createBlock(*BBI->Atom); BBI->BB = &MCFN.createBlock(*BBI->Atom);
@ -247,17 +259,19 @@ void MCObjectDisassembler::buildCFG(MCModule *Module) {
} }
// Set preds/succs. // Set preds/succs.
for (size_t WI = 0; WI < Worklist.size(); ++WI) { for (size_t wi = 0; wi < Worklist.size(); ++wi) {
BBInfo *BBI = Worklist[WI]; BBInfo *BBI = Worklist[wi];
MCBasicBlock *MCBB = BBI->BB; MCBasicBlock *MCBB = BBI->BB;
if (!MCBB) if (!MCBB)
continue; continue;
for (BBInfoSetTy::iterator SI = BBI->Succs.begin(), SE = BBI->Succs.end(); for (BBInfoSetTy::iterator SI = BBI->Succs.begin(), SE = BBI->Succs.end();
SI != SE; ++SI) SI != SE; ++SI)
MCBB->addSuccessor((*SI)->BB); if ((*SI)->BB)
MCBB->addSuccessor((*SI)->BB);
for (BBInfoSetTy::iterator PI = BBI->Preds.begin(), PE = BBI->Preds.end(); for (BBInfoSetTy::iterator PI = BBI->Preds.begin(), PE = BBI->Preds.end();
PI != PE; ++PI) PI != PE; ++PI)
MCBB->addPredecessor((*PI)->BB); if ((*PI)->BB)
MCBB->addPredecessor((*PI)->BB);
} }
} }
} }