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/OwningPtr.h"
14 #include "llvm/MC/MCRelocationInfo.h"
15 #include "llvm/MC/MCSymbolizer.h"
16 #include "llvm/Support/DataTypes.h"
21 class MCSubtargetInfo;
26 /// MCDisassembler - Superclass for all disassemblers. Consumes a memory region
27 /// and provides an array of assembly instructions.
28 class MCDisassembler {
30 /// Ternary decode status. Most backends will just use Fail and
31 /// Success, however some have a concept of an instruction with
32 /// understandable semantics but which is architecturally
33 /// incorrect. An example of this is ARM UNPREDICTABLE instructions
34 /// which are disassemblable but cause undefined behaviour.
36 /// Because it makes sense to disassemble these instructions, there
37 /// is a "soft fail" failure mode that indicates the MCInst& is
38 /// valid but architecturally incorrect.
40 /// The enum numbers are deliberately chosen such that reduction
41 /// from Success->SoftFail ->Fail can be done with a simple
44 /// LEFT & TOP = | Success Unpredictable Fail
45 /// --------------+-----------------------------------
46 /// Success | Success Unpredictable Fail
47 /// Unpredictable | Unpredictable Unpredictable Fail
48 /// Fail | Fail Fail Fail
50 /// An easy way of encoding this is as 0b11, 0b01, 0b00 for
51 /// Success, SoftFail, Fail respectively.
58 /// Constructor - Performs initial setup for the disassembler.
59 MCDisassembler(const MCSubtargetInfo &STI)
60 : STI(STI), Symbolizer(), CommentStream(0) {}
62 virtual ~MCDisassembler();
64 /// getInstruction - Returns the disassembly of a single instruction.
66 /// @param instr - An MCInst to populate with the contents of the
68 /// @param size - A value to populate with the size of the instruction, or
69 /// the number of bytes consumed while attempting to decode
70 /// an invalid instruction.
71 /// @param region - The memory object to use as a source for machine code.
72 /// @param address - The address, in the memory space of region, of the first
73 /// byte of the instruction.
74 /// @param vStream - The stream to print warnings and diagnostic messages on.
75 /// @param cStream - The stream to print comments and annotations on.
76 /// @return - MCDisassembler::Success if the instruction is valid,
77 /// MCDisassembler::SoftFail if the instruction was
78 /// disassemblable but invalid,
79 /// MCDisassembler::Fail if the instruction was invalid.
80 virtual DecodeStatus getInstruction(MCInst& instr,
82 const MemoryObject ®ion,
85 raw_ostream &cStream) const = 0;
88 // Subtarget information, for instruction decoding predicates if required.
89 const MCSubtargetInfo &STI;
90 std::unique_ptr<MCSymbolizer> Symbolizer;
93 // Helpers around MCSymbolizer
94 bool tryAddingSymbolicOperand(MCInst &Inst,
96 uint64_t Address, bool IsBranch,
97 uint64_t Offset, uint64_t InstSize) const;
99 void tryAddingPcLoadReferenceComment(int64_t Value, uint64_t Address) const;
101 /// Set \p Symzer as the current symbolizer.
102 /// This takes ownership of \p Symzer, and deletes the previously set one.
103 void setSymbolizer(std::unique_ptr<MCSymbolizer> Symzer);
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;