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ef99356dfe
This patch builds on some existing code to do CFG reconstruction from a disassembled binary: - MCModule represents the binary, and has a list of MCAtoms. - MCAtom represents either disassembled instructions (MCTextAtom), or contiguous data (MCDataAtom), and covers a specific range of addresses. - MCBasicBlock and MCFunction form the reconstructed CFG. An MCBB is backed by an MCTextAtom, and has the usual successors/predecessors. - MCObjectDisassembler creates a module from an ObjectFile using a disassembler. It first builds an atom for each section. It can also construct the CFG, and this splits the text atoms into basic blocks. MCModule and MCAtom were only sketched out; MCFunction and MCBB were implemented under the experimental "-cfg" llvm-objdump -macho option. This cleans them up for further use; llvm-objdump -d -cfg now generates graphviz files for each function found in the binary. In the future, MCObjectDisassembler may be the right place to do "intelligent" disassembly: for example, handling constant islands is just a matter of splitting the atom, using information that may be available in the ObjectFile. Also, better initial atom formation than just using sections is possible using symbols (and things like Mach-O's function_starts load command). This brings two minor regressions in llvm-objdump -macho -cfg: - The printing of a relocation's referenced symbol. - An annotation on loop BBs, i.e., which are their own successor. Relocation printing is replaced by the MCSymbolizer; the basic CFG annotation will be superseded by more related functionality. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182628 91177308-0d34-0410-b5e6-96231b3b80d8
111 lines
3.2 KiB
C++
111 lines
3.2 KiB
C++
//===- lib/MC/MCAtom.cpp - MCAtom implementation --------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/MC/MCAtom.h"
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#include "llvm/MC/MCModule.h"
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#include "llvm/Support/ErrorHandling.h"
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#include <iterator>
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using namespace llvm;
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void MCAtom::remap(uint64_t NewBegin, uint64_t NewEnd) {
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Parent->remap(this, NewBegin, NewEnd);
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}
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void MCAtom::remapForTruncate(uint64_t TruncPt) {
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assert((TruncPt >= Begin && TruncPt < End) &&
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"Truncation point not contained in atom!");
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remap(Begin, TruncPt);
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}
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void MCAtom::remapForSplit(uint64_t SplitPt,
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uint64_t &LBegin, uint64_t &LEnd,
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uint64_t &RBegin, uint64_t &REnd) {
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assert((SplitPt > Begin && SplitPt <= End) &&
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"Splitting at point not contained in atom!");
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// Compute the new begin/end points.
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LBegin = Begin;
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LEnd = SplitPt - 1;
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RBegin = SplitPt;
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REnd = End;
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// Remap this atom to become the lower of the two new ones.
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remap(LBegin, LEnd);
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}
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// MCDataAtom
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void MCDataAtom::addData(const MCData &D) {
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Data.push_back(D);
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if (Data.size() > Begin - End)
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remap(Begin, End + 1);
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}
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void MCDataAtom::truncate(uint64_t TruncPt) {
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remapForTruncate(TruncPt);
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Data.resize(TruncPt - Begin + 1);
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}
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MCDataAtom *MCDataAtom::split(uint64_t SplitPt) {
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uint64_t LBegin, LEnd, RBegin, REnd;
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remapForSplit(SplitPt, LBegin, LEnd, RBegin, REnd);
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MCDataAtom *RightAtom = Parent->createDataAtom(RBegin, REnd);
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RightAtom->setName(getName());
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std::vector<MCData>::iterator I = Data.begin() + (RBegin - LBegin);
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assert(I != Data.end() && "Split point not found in range!");
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std::copy(I, Data.end(), std::back_inserter(RightAtom->Data));
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Data.erase(I, Data.end());
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return RightAtom;
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}
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// MCTextAtom
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void MCTextAtom::addInst(const MCInst &I, uint64_t Size) {
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if (NextInstAddress > End)
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remap(Begin, NextInstAddress);
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Insts.push_back(MCDecodedInst(I, NextInstAddress, Size));
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NextInstAddress += Size;
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}
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void MCTextAtom::truncate(uint64_t TruncPt) {
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remapForTruncate(TruncPt);
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InstListTy::iterator I = Insts.begin();
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while (I != Insts.end() && I->Address <= TruncPt) ++I;
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assert(I != Insts.end() && "Truncation point not found in disassembly!");
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assert(I->Address == TruncPt + 1 &&
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"Truncation point does not fall on instruction boundary");
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Insts.erase(I, Insts.end());
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}
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MCTextAtom *MCTextAtom::split(uint64_t SplitPt) {
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uint64_t LBegin, LEnd, RBegin, REnd;
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remapForSplit(SplitPt, LBegin, LEnd, RBegin, REnd);
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MCTextAtom *RightAtom = Parent->createTextAtom(RBegin, REnd);
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RightAtom->setName(getName());
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InstListTy::iterator I = Insts.begin();
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while (I != Insts.end() && I->Address < SplitPt) ++I;
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assert(I != Insts.end() && "Split point not found in disassembly!");
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assert(I->Address == SplitPt &&
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"Split point does not fall on instruction boundary!");
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std::copy(I, Insts.end(), std::back_inserter(RightAtom->Insts));
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Insts.erase(I, Insts.end());
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return RightAtom;
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}
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