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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 Relocation printing is replaced by the MCSymbolizer; the basic CFG annotation will be superseded by more related functionality.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
70 lines
2.6 KiB
C++
70 lines
2.6 KiB
C++
//===-- llvm/MC/MCObjectDisassembler.h --------------------------*- C++ -*-===//
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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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//
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// This file contains the declaration of the MCObjectDisassembler class, which
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// can be used to construct an MCModule and an MC CFG from an ObjectFile.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_MC_MCOBJECTDISASSEMBLER_H
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#define LLVM_MC_MCOBJECTDISASSEMBLER_H
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namespace llvm {
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namespace object {
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class ObjectFile;
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}
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class MCBasicBlock;
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class MCDisassembler;
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class MCFunction;
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class MCInstrAnalysis;
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class MCModule;
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/// \brief Disassemble an ObjectFile to an MCModule and MCFunctions.
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/// This class builds on MCDisassembler to disassemble whole sections, creating
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/// MCAtom (MCTextAtom for disassembled sections and MCDataAtom for raw data).
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/// It can also be used to create a control flow graph consisting of MCFunctions
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/// and MCBasicBlocks.
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class MCObjectDisassembler {
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const object::ObjectFile &Obj;
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const MCDisassembler &Dis;
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const MCInstrAnalysis &MIA;
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public:
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MCObjectDisassembler(const object::ObjectFile &Obj,
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const MCDisassembler &Dis,
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const MCInstrAnalysis &MIA);
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/// \brief Build an MCModule, creating atoms and optionally functions.
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/// \param withCFG Also build a CFG by adding MCFunctions to the Module.
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/// If withCFG is false, the MCModule built only contains atoms, representing
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/// what was found in the object file. If withCFG is true, MCFunctions are
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/// created, containing MCBasicBlocks. All text atoms are split to form basic
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/// block atoms, which then each back an MCBasicBlock.
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MCModule *buildModule(bool withCFG = false);
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private:
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/// \brief Fill \p Module by creating an atom for each section.
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/// This could be made much smarter, using information like symbols, but also
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/// format-specific features, like mach-o function_start or data_in_code LCs.
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void buildSectionAtoms(MCModule *Module);
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/// \brief Enrich \p Module with a CFG consisting of MCFunctions.
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/// \param Module An MCModule returned by buildModule, with no CFG.
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/// NOTE: Each MCBasicBlock in a MCFunction is backed by a single MCTextAtom.
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/// When the CFG is built, contiguous instructions that were previously in a
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/// single MCTextAtom will be split in multiple basic block atoms.
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void buildCFG(MCModule *Module);
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};
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}
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#endif
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