diff options
Diffstat (limited to 'include/llvm/MC/MCDisassembler.h')
| -rw-r--r-- | include/llvm/MC/MCDisassembler.h | 35 |
1 files changed, 33 insertions, 2 deletions
diff --git a/include/llvm/MC/MCDisassembler.h b/include/llvm/MC/MCDisassembler.h index ce8759a882..adcb88254e 100644 --- a/include/llvm/MC/MCDisassembler.h +++ b/include/llvm/MC/MCDisassembler.h @@ -25,6 +25,34 @@ struct EDInstInfo; /// and provides an array of assembly instructions. class MCDisassembler { public: + /// Ternary decode status. Most backends will just use Fail and + /// Success, however some have a concept of an instruction with + /// understandable semantics but which is architecturally + /// incorrect. An example of this is ARM UNPREDICTABLE instructions + /// which are disassemblable but cause undefined behaviour. + /// + /// Because it makes sense to disassemble these instructions, there + /// is a "soft fail" failure mode that indicates the MCInst& is + /// valid but architecturally incorrect. + /// + /// The enum numbers are deliberately chosen such that reduction + /// from Success->SoftFail ->Fail can be done with a simple + /// bitwise-AND: + /// + /// LEFT & TOP = | Success Unpredictable Fail + /// --------------+----------------------------------- + /// Success | Success Unpredictable Fail + /// Unpredictable | Unpredictable Unpredictable Fail + /// Fail | Fail Fail Fail + /// + /// An easy way of encoding this is as 0b11, 0b01, 0b00 for + /// Success, SoftFail, Fail respectively. + enum DecodeStatus { + Fail = 0, + SoftFail = 1, + Success = 3 + }; + /// Constructor - Performs initial setup for the disassembler. MCDisassembler() : GetOpInfo(0), DisInfo(0), Ctx(0) {} @@ -41,8 +69,11 @@ public: /// @param address - The address, in the memory space of region, of the first /// byte of the instruction. /// @param vStream - The stream to print warnings and diagnostic messages on. - /// @return - True if the instruction is valid; false otherwise. - virtual bool getInstruction(MCInst& instr, + /// @return - MCDisassembler::Success if the instruction is valid, + /// MCDisassembler::SoftFail if the instruction was + /// disassemblable but invalid, + /// MCDisassembler::Fail if the instruction was invalid. + virtual DecodeStatus getInstruction(MCInst& instr, uint64_t& size, const MemoryObject ®ion, uint64_t address, |