1 //===-- llvm/MC/MCDisassembler.h - Disassembler interface -------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
9 #ifndef LLVM_MC_MCDISASSEMBLER_H
10 #define LLVM_MC_MCDISASSEMBLER_H
12 #include "llvm-c/Disassembler.h"
13 #include "llvm/ADT/ArrayRef.h"
14 #include "llvm/MC/MCRelocationInfo.h"
15 #include "llvm/MC/MCSymbolizer.h"
16 #include "llvm/Support/DataTypes.h"
21 class MCSubtargetInfo;
25 /// Superclass for all disassemblers. Consumes a memory region and provides an
26 /// array of assembly instructions.
27 class MCDisassembler {
29 /// Ternary decode status. Most backends will just use Fail and
30 /// Success, however some have a concept of an instruction with
31 /// understandable semantics but which is architecturally
32 /// incorrect. An example of this is ARM UNPREDICTABLE instructions
33 /// which are disassemblable but cause undefined behaviour.
35 /// Because it makes sense to disassemble these instructions, there
36 /// is a "soft fail" failure mode that indicates the MCInst& is
37 /// valid but architecturally incorrect.
39 /// The enum numbers are deliberately chosen such that reduction
40 /// from Success->SoftFail ->Fail can be done with a simple
43 /// LEFT & TOP = | Success Unpredictable Fail
44 /// --------------+-----------------------------------
45 /// Success | Success Unpredictable Fail
46 /// Unpredictable | Unpredictable Unpredictable Fail
47 /// Fail | Fail Fail Fail
49 /// An easy way of encoding this is as 0b11, 0b01, 0b00 for
50 /// Success, SoftFail, Fail respectively.
57 MCDisassembler(const MCSubtargetInfo &STI, MCContext &Ctx)
58 : Ctx(Ctx), STI(STI), Symbolizer(), CommentStream(nullptr) {}
60 virtual ~MCDisassembler();
62 /// Returns the disassembly of a single instruction.
64 /// @param Instr - An MCInst to populate with the contents of the
66 /// @param Size - A value to populate with the size of the instruction, or
67 /// the number of bytes consumed while attempting to decode
68 /// an invalid instruction.
69 /// @param Address - The address, in the memory space of region, of the first
70 /// byte of the instruction.
71 /// @param VStream - The stream to print warnings and diagnostic messages on.
72 /// @param CStream - The stream to print comments and annotations on.
73 /// @return - MCDisassembler::Success if the instruction is valid,
74 /// MCDisassembler::SoftFail if the instruction was
75 /// disassemblable but invalid,
76 /// MCDisassembler::Fail if the instruction was invalid.
77 virtual DecodeStatus getInstruction(MCInst &Instr, uint64_t &Size,
78 ArrayRef<uint8_t> Bytes, uint64_t Address,
80 raw_ostream &CStream) const = 0;
86 // Subtarget information, for instruction decoding predicates if required.
87 const MCSubtargetInfo &STI;
88 std::unique_ptr<MCSymbolizer> Symbolizer;
91 // Helpers around MCSymbolizer
92 bool tryAddingSymbolicOperand(MCInst &Inst,
94 uint64_t Address, bool IsBranch,
95 uint64_t Offset, uint64_t InstSize) const;
97 void tryAddingPcLoadReferenceComment(int64_t Value, uint64_t Address) const;
99 /// Set \p Symzer as the current symbolizer.
100 /// This takes ownership of \p Symzer, and deletes the previously set one.
101 void setSymbolizer(std::unique_ptr<MCSymbolizer> Symzer);
103 MCContext& getContext() const { return Ctx; }
105 const MCSubtargetInfo& getSubtargetInfo() const { return STI; }
107 // Marked mutable because we cache it inside the disassembler, rather than
108 // having to pass it around as an argument through all the autogenerated code.
109 mutable raw_ostream *CommentStream;