198 lines
7.7 KiB
C++
198 lines
7.7 KiB
C++
//===- llvm/MC/MCDisassembler.h - Disassembler interface --------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_MC_MCDISASSEMBLER_MCDISASSEMBLER_H
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#define LLVM_MC_MCDISASSEMBLER_MCDISASSEMBLER_H
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#include "llvm/ADT/Optional.h"
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#include "llvm/ADT/StringRef.h"
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#include "llvm/BinaryFormat/XCOFF.h"
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#include "llvm/MC/MCDisassembler/MCSymbolizer.h"
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#include <cstdint>
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#include <memory>
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#include <vector>
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namespace llvm {
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struct XCOFFSymbolInfo {
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Optional<XCOFF::StorageMappingClass> StorageMappingClass;
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Optional<uint32_t> Index;
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bool IsLabel;
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XCOFFSymbolInfo(Optional<XCOFF::StorageMappingClass> Smc,
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Optional<uint32_t> Idx, bool Label)
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: StorageMappingClass(Smc), Index(Idx), IsLabel(Label) {}
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bool operator<(const XCOFFSymbolInfo &SymInfo) const;
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};
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struct SymbolInfoTy {
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uint64_t Addr;
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StringRef Name;
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union {
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uint8_t Type;
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XCOFFSymbolInfo XCOFFSymInfo;
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};
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private:
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bool IsXCOFF;
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public:
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SymbolInfoTy(uint64_t Addr, StringRef Name,
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Optional<XCOFF::StorageMappingClass> Smc, Optional<uint32_t> Idx,
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bool Label)
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: Addr(Addr), Name(Name), XCOFFSymInfo(Smc, Idx, Label), IsXCOFF(true) {}
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SymbolInfoTy(uint64_t Addr, StringRef Name, uint8_t Type)
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: Addr(Addr), Name(Name), Type(Type), IsXCOFF(false) {}
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bool isXCOFF() const { return IsXCOFF; }
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private:
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friend bool operator<(const SymbolInfoTy &P1, const SymbolInfoTy &P2) {
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assert(P1.IsXCOFF == P2.IsXCOFF &&
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"P1.IsXCOFF should be equal to P2.IsXCOFF.");
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if (P1.IsXCOFF)
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return std::tie(P1.Addr, P1.XCOFFSymInfo, P1.Name) <
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std::tie(P2.Addr, P2.XCOFFSymInfo, P2.Name);
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return std::tie(P1.Addr, P1.Name, P1.Type) <
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std::tie(P2.Addr, P2.Name, P2.Type);
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}
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};
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using SectionSymbolsTy = std::vector<SymbolInfoTy>;
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template <typename T> class ArrayRef;
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class MCContext;
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class MCInst;
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class MCSubtargetInfo;
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class raw_ostream;
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/// Superclass for all disassemblers. Consumes a memory region and provides an
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/// array of assembly instructions.
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class MCDisassembler {
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public:
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/// Ternary decode status. Most backends will just use Fail and
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/// Success, however some have a concept of an instruction with
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/// understandable semantics but which is architecturally
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/// incorrect. An example of this is ARM UNPREDICTABLE instructions
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/// which are disassemblable but cause undefined behaviour.
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///
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/// Because it makes sense to disassemble these instructions, there
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/// is a "soft fail" failure mode that indicates the MCInst& is
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/// valid but architecturally incorrect.
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///
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/// The enum numbers are deliberately chosen such that reduction
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/// from Success->SoftFail ->Fail can be done with a simple
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/// bitwise-AND:
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///
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/// LEFT & TOP = | Success Unpredictable Fail
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/// --------------+-----------------------------------
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/// Success | Success Unpredictable Fail
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/// Unpredictable | Unpredictable Unpredictable Fail
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/// Fail | Fail Fail Fail
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///
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/// An easy way of encoding this is as 0b11, 0b01, 0b00 for
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/// Success, SoftFail, Fail respectively.
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enum DecodeStatus {
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Fail = 0,
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SoftFail = 1,
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Success = 3
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};
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MCDisassembler(const MCSubtargetInfo &STI, MCContext &Ctx)
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: Ctx(Ctx), STI(STI) {}
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virtual ~MCDisassembler();
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/// Returns the disassembly of a single instruction.
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///
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/// \param Instr - An MCInst to populate with the contents of the
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/// instruction.
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/// \param Size - A value to populate with the size of the instruction, or
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/// the number of bytes consumed while attempting to decode
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/// an invalid instruction.
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/// \param Address - The address, in the memory space of region, of the first
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/// byte of the instruction.
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/// \param Bytes - A reference to the actual bytes of the instruction.
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/// \param CStream - The stream to print comments and annotations on.
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/// \return - MCDisassembler::Success if the instruction is valid,
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/// MCDisassembler::SoftFail if the instruction was
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/// disassemblable but invalid,
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/// MCDisassembler::Fail if the instruction was invalid.
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virtual DecodeStatus getInstruction(MCInst &Instr, uint64_t &Size,
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ArrayRef<uint8_t> Bytes, uint64_t Address,
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raw_ostream &CStream) const = 0;
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/// Used to perform separate target specific disassembly for a particular
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/// symbol. May parse any prelude that precedes instructions after the
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/// start of a symbol, or the entire symbol.
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/// This is used for example by WebAssembly to decode preludes.
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///
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/// Base implementation returns None. So all targets by default ignore to
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/// treat symbols separately.
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///
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/// \param Symbol - The symbol.
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/// \param Size - The number of bytes consumed.
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/// \param Address - The address, in the memory space of region, of the first
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/// byte of the symbol.
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/// \param Bytes - A reference to the actual bytes at the symbol location.
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/// \param CStream - The stream to print comments and annotations on.
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/// \return - MCDisassembler::Success if bytes are decoded
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/// successfully. Size must hold the number of bytes that
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/// were decoded.
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/// - MCDisassembler::Fail if the bytes are invalid. Size
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/// must hold the number of bytes that were decoded before
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/// failing. The target must print nothing. This can be
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/// done by buffering the output if needed.
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/// - None if the target doesn't want to handle the symbol
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/// separately. Value of Size is ignored in this case.
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virtual Optional<DecodeStatus>
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onSymbolStart(SymbolInfoTy &Symbol, uint64_t &Size, ArrayRef<uint8_t> Bytes,
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uint64_t Address, raw_ostream &CStream) const;
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// TODO:
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// Implement similar hooks that can be used at other points during
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// disassembly. Something along the following lines:
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// - onBeforeInstructionDecode()
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// - onAfterInstructionDecode()
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// - onSymbolEnd()
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// It should help move much of the target specific code from llvm-objdump to
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// respective target disassemblers.
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private:
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MCContext &Ctx;
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protected:
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// Subtarget information, for instruction decoding predicates if required.
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const MCSubtargetInfo &STI;
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std::unique_ptr<MCSymbolizer> Symbolizer;
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public:
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// Helpers around MCSymbolizer
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bool tryAddingSymbolicOperand(MCInst &Inst,
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int64_t Value,
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uint64_t Address, bool IsBranch,
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uint64_t Offset, uint64_t InstSize) const;
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void tryAddingPcLoadReferenceComment(int64_t Value, uint64_t Address) const;
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/// Set \p Symzer as the current symbolizer.
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/// This takes ownership of \p Symzer, and deletes the previously set one.
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void setSymbolizer(std::unique_ptr<MCSymbolizer> Symzer);
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MCContext& getContext() const { return Ctx; }
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const MCSubtargetInfo& getSubtargetInfo() const { return STI; }
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// Marked mutable because we cache it inside the disassembler, rather than
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// having to pass it around as an argument through all the autogenerated code.
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mutable raw_ostream *CommentStream = nullptr;
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};
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} // end namespace llvm
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#endif // LLVM_MC_MCDISASSEMBLER_MCDISASSEMBLER_H
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