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/MCSymbolizer.h"
15 #include "llvm/MC/MCRelocationInfo.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) : GetOpInfo(0), SymbolLookUp(0),
61 STI(STI), Symbolizer(0),
64 virtual ~MCDisassembler();
66 /// getInstruction - Returns the disassembly of a single instruction.
68 /// @param instr - An MCInst to populate with the contents of the
70 /// @param size - A value to populate with the size of the instruction, or
71 /// the number of bytes consumed while attempting to decode
72 /// an invalid instruction.
73 /// @param region - The memory object to use as a source for machine code.
74 /// @param address - The address, in the memory space of region, of the first
75 /// byte of the instruction.
76 /// @param vStream - The stream to print warnings and diagnostic messages on.
77 /// @param cStream - The stream to print comments and annotations on.
78 /// @return - MCDisassembler::Success if the instruction is valid,
79 /// MCDisassembler::SoftFail if the instruction was
80 /// disassemblable but invalid,
81 /// MCDisassembler::Fail if the instruction was invalid.
82 virtual DecodeStatus getInstruction(MCInst& instr,
84 const MemoryObject ®ion,
87 raw_ostream &cStream) const = 0;
90 // Hooks for symbolic disassembly via the public 'C' interface.
92 // The function to get the symbolic information for operands.
93 LLVMOpInfoCallback GetOpInfo;
94 // The function to lookup a symbol name.
95 LLVMSymbolLookupCallback SymbolLookUp;
96 // The pointer to the block of symbolic information for above call back.
98 // The assembly context for creating symbols and MCExprs in place of
99 // immediate operands when there is symbolic information.
103 // Subtarget information, for instruction decoding predicates if required.
104 const MCSubtargetInfo &STI;
105 OwningPtr<MCSymbolizer> Symbolizer;
108 // Helpers around MCSymbolizer
109 bool tryAddingSymbolicOperand(MCInst &Inst,
111 uint64_t Address, bool IsBranch,
112 uint64_t Offset, uint64_t InstSize) const;
114 void tryAddingPcLoadReferenceComment(int64_t Value, uint64_t Address) const;
116 /// Set \p Symzer as the current symbolizer.
117 /// This takes ownership of \p Symzer, and deletes the previously set one.
118 void setSymbolizer(OwningPtr<MCSymbolizer> &Symzer);
120 /// Sets up an external symbolizer that uses the C API callbacks.
121 void setupForSymbolicDisassembly(LLVMOpInfoCallback GetOpInfo,
122 LLVMSymbolLookupCallback SymbolLookUp,
125 OwningPtr<MCRelocationInfo> &RelInfo);
127 LLVMOpInfoCallback getLLVMOpInfoCallback() const { return GetOpInfo; }
128 LLVMSymbolLookupCallback getLLVMSymbolLookupCallback() const {
131 void *getDisInfoBlock() const { return DisInfo; }
132 MCContext *getMCContext() const { return Ctx; }
134 const MCSubtargetInfo& getSubtargetInfo() const { return STI; }
136 // Marked mutable because we cache it inside the disassembler, rather than
137 // having to pass it around as an argument through all the autogenerated code.
138 mutable raw_ostream *CommentStream;