mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-07-24 08:29:39 +00:00
41ab14b725
- Add overrides for ARM. - Teach llvm-objdump to use this instead of plain MCInstrDesc. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137059 91177308-0d34-0410-b5e6-96231b3b80d8
112 lines
3.9 KiB
C++
112 lines
3.9 KiB
C++
//===-- MCFunction.cpp ----------------------------------------------------===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This file defines the algorithm to break down a region of machine code
|
|
// into basic blocks and try to reconstruct a CFG from it.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "MCFunction.h"
|
|
#include "llvm/ADT/STLExtras.h"
|
|
#include "llvm/MC/MCDisassembler.h"
|
|
#include "llvm/MC/MCInst.h"
|
|
#include "llvm/MC/MCInstPrinter.h"
|
|
#include "llvm/MC/MCInstrAnalysis.h"
|
|
#include "llvm/MC/MCInstrDesc.h"
|
|
#include "llvm/MC/MCInstrInfo.h"
|
|
#include "llvm/Support/MemoryObject.h"
|
|
#include "llvm/Support/raw_ostream.h"
|
|
#include "llvm/Support/system_error.h"
|
|
#include <set>
|
|
using namespace llvm;
|
|
|
|
MCFunction
|
|
MCFunction::createFunctionFromMC(StringRef Name, const MCDisassembler *DisAsm,
|
|
const MemoryObject &Region, uint64_t Start,
|
|
uint64_t End, const MCInstrAnalysis *Ana,
|
|
raw_ostream &DebugOut) {
|
|
std::set<uint64_t> Splits;
|
|
Splits.insert(Start);
|
|
std::vector<MCDecodedInst> Instructions;
|
|
uint64_t Size;
|
|
|
|
// Disassemble code and gather basic block split points.
|
|
for (uint64_t Index = Start; Index < End; Index += Size) {
|
|
MCInst Inst;
|
|
|
|
if (DisAsm->getInstruction(Inst, Size, Region, Index, DebugOut)) {
|
|
if (Ana->isBranch(Inst)) {
|
|
uint64_t targ = Ana->evaluateBranch(Inst, Index, Size);
|
|
// FIXME: Distinguish relocations from nop jumps.
|
|
if (targ != -1ULL && (targ == Index+Size || targ >= End)) {
|
|
Instructions.push_back(MCDecodedInst(Index, Size, Inst));
|
|
continue; // Skip branches that leave the function.
|
|
}
|
|
if (targ != -1ULL)
|
|
Splits.insert(targ);
|
|
Splits.insert(Index+Size);
|
|
} else if (Ana->isReturn(Inst)) {
|
|
Splits.insert(Index+Size);
|
|
}
|
|
|
|
Instructions.push_back(MCDecodedInst(Index, Size, Inst));
|
|
} else {
|
|
errs() << "warning: invalid instruction encoding\n";
|
|
if (Size == 0)
|
|
Size = 1; // skip illegible bytes
|
|
}
|
|
|
|
}
|
|
|
|
MCFunction f(Name);
|
|
|
|
// Create basic blocks.
|
|
unsigned ii = 0, ie = Instructions.size();
|
|
for (std::set<uint64_t>::iterator spi = Splits.begin(),
|
|
spe = Splits.end(); spi != spe; ++spi) {
|
|
MCBasicBlock BB;
|
|
uint64_t BlockEnd = llvm::next(spi) == spe ? End : *llvm::next(spi);
|
|
// Add instructions to the BB.
|
|
for (; ii != ie; ++ii) {
|
|
if (Instructions[ii].Address < *spi ||
|
|
Instructions[ii].Address >= BlockEnd)
|
|
break;
|
|
BB.addInst(Instructions[ii]);
|
|
}
|
|
f.addBlock(*spi, BB);
|
|
}
|
|
|
|
// Calculate successors of each block.
|
|
for (MCFunction::iterator i = f.begin(), e = f.end(); i != e; ++i) {
|
|
MCBasicBlock &BB = i->second;
|
|
if (BB.getInsts().empty()) continue;
|
|
const MCDecodedInst &Inst = BB.getInsts().back();
|
|
|
|
if (Ana->isBranch(Inst.Inst)) {
|
|
uint64_t targ = Ana->evaluateBranch(Inst.Inst, Inst.Address, Inst.Size);
|
|
if (targ == -1ULL) {
|
|
// Indirect branch. Bail and add all blocks of the function as a
|
|
// successor.
|
|
for (MCFunction::iterator i = f.begin(), e = f.end(); i != e; ++i)
|
|
BB.addSucc(&i->second);
|
|
} else if (targ != Inst.Address+Inst.Size)
|
|
BB.addSucc(&f.getBlockAtAddress(targ));
|
|
// Conditional branches can also fall through to the next block.
|
|
if (Ana->isConditionalBranch(Inst.Inst) && llvm::next(i) != e)
|
|
BB.addSucc(&llvm::next(i)->second);
|
|
} else {
|
|
// No branch. Fall through to the next block.
|
|
if (!Ana->isReturn(Inst.Inst) && llvm::next(i) != e)
|
|
BB.addSucc(&llvm::next(i)->second);
|
|
}
|
|
}
|
|
|
|
return f;
|
|
}
|