Commit 933e616b authored by Simon Dardis's avatar Simon Dardis
Browse files

Merging r296105, r296016 and 296111: 

------------------------------------------------------------------------
r296105 | sdardis | 2017-02-24 10:50:27 +0000 (Fri, 24 Feb 2017) | 13 lines

[mips][mc] Fix a crash when disassembling odd sized sections

Make the MIPS disassembler consistent with the other targets in returning
a Size of zero when the input buffer cannot contain an instruction due
to it's size. Previously it reported the minimum instruction size when
it failed due to the buffer not being big enough for an instruction
causing llvm-objdump to crash when disassembling all sections.

Reviewers: slthakur

Differential Revision: https://reviews.llvm.org/D29984


------------------------------------------------------------------------
------------------------------------------------------------------------
r296106 | sdardis | 2017-02-24 10:51:27 +0000 (Fri, 24 Feb 2017) | 5 lines

[mips][mc] Fix a crash when disassembling odd sized sections

Corresponding test.


------------------------------------------------------------------------
------------------------------------------------------------------------
r296111 | rovka | 2017-02-24 12:47:11 +0000 (Fri, 24 Feb 2017) | 1 line

Fixup r296105 - only run tests on Mips
------------------------------------------------------------------------

llvm-svn: 301169
parent d14b74f6

llvm/lib/Target/Mips/Disassembler/MipsDisassembler.cpp

+21 −30
Original line number Diff line number Diff line
@@ -1106,6 +1106,7 @@ DecodeStatus MipsDisassembler::getInstruction(MCInst &Instr, uint64_t &Size, 
                                              raw_ostream &CStream) const {

  uint32_t Insn;

  DecodeStatus Result;

  Size = 0;



  if (IsMicroMips) {

    Result = readInstruction16(Bytes, Address, Size, Insn, IsBigEndian);
@@ -1168,98 +1169,88 @@ DecodeStatus MipsDisassembler::getInstruction(MCInst &Instr, uint64_t &Size, 
      }

    }



    // This is an invalid instruction. Let the disassembler move forward by the

    // minimum instruction size.

    // This is an invalid instruction. Claim that the Size is 2 bytes. Since

    // microMIPS instructions have a minimum alignment of 2, the next 2 bytes

    // could form a valid instruction. The two bytes we rejected as an

    // instruction could have actually beeen an inline constant pool that is

    // unconditionally branched over.

    Size = 2;

    return MCDisassembler::Fail;

  }



  // Attempt to read the instruction so that we can attempt to decode it. If

  // the buffer is not 4 bytes long, let the higher level logic figure out

  // what to do with a size of zero and MCDisassembler::Fail.

  Result = readInstruction32(Bytes, Address, Size, Insn, IsBigEndian, false);

  if (Result == MCDisassembler::Fail) {

    Size = 4;

  if (Result == MCDisassembler::Fail)

    return MCDisassembler::Fail;

  }



  // The only instruction size for standard encoded MIPS.

  Size = 4;



  if (hasCOP3()) {

    DEBUG(dbgs() << "Trying COP3_ table (32-bit opcodes):\n");

    Result =

        decodeInstruction(DecoderTableCOP3_32, Instr, Insn, Address, this, STI);

    if (Result != MCDisassembler::Fail) {

      Size = 4;

    if (Result != MCDisassembler::Fail)

      return Result;

  }

  }



  if (hasMips32r6() && isGP64()) {

    DEBUG(dbgs() << "Trying Mips32r6_64r6 (GPR64) table (32-bit opcodes):\n");

    Result = decodeInstruction(DecoderTableMips32r6_64r6_GP6432, Instr, Insn,

                               Address, this, STI);

    if (Result != MCDisassembler::Fail) {

      Size = 4;

    if (Result != MCDisassembler::Fail)

      return Result;

  }

  }



  if (hasMips32r6() && isPTR64()) {

    DEBUG(dbgs() << "Trying Mips32r6_64r6 (PTR64) table (32-bit opcodes):\n");

    Result = decodeInstruction(DecoderTableMips32r6_64r6_PTR6432, Instr, Insn,

                               Address, this, STI);

    if (Result != MCDisassembler::Fail) {

      Size = 4;

    if (Result != MCDisassembler::Fail)

      return Result;

  }

  }



  if (hasMips32r6()) {

    DEBUG(dbgs() << "Trying Mips32r6_64r6 table (32-bit opcodes):\n");

    Result = decodeInstruction(DecoderTableMips32r6_64r632, Instr, Insn,

                               Address, this, STI);

    if (Result != MCDisassembler::Fail) {

      Size = 4;

    if (Result != MCDisassembler::Fail)

      return Result;

  }

  }



  if (hasMips2() && isPTR64()) {

    DEBUG(dbgs() << "Trying Mips32r6_64r6 (PTR64) table (32-bit opcodes):\n");

    Result = decodeInstruction(DecoderTableMips32_64_PTR6432, Instr, Insn,

                               Address, this, STI);

    if (Result != MCDisassembler::Fail) {

      Size = 4;

    if (Result != MCDisassembler::Fail)

      return Result;

  }

  }



  if (hasCnMips()) {

    DEBUG(dbgs() << "Trying CnMips table (32-bit opcodes):\n");

    Result = decodeInstruction(DecoderTableCnMips32, Instr, Insn,

                               Address, this, STI);

    if (Result != MCDisassembler::Fail) {

      Size = 4;

    if (Result != MCDisassembler::Fail)

      return Result;

  }

  }



  if (isGP64()) {

    DEBUG(dbgs() << "Trying Mips64 (GPR64) table (32-bit opcodes):\n");

    Result = decodeInstruction(DecoderTableMips6432, Instr, Insn,

                               Address, this, STI);

    if (Result != MCDisassembler::Fail) {

      Size = 4;

    if (Result != MCDisassembler::Fail)

      return Result;

  }

  }



  DEBUG(dbgs() << "Trying Mips table (32-bit opcodes):\n");

  // Calling the auto-generated decoder function.

  Result =

      decodeInstruction(DecoderTableMips32, Instr, Insn, Address, this, STI);

  if (Result != MCDisassembler::Fail) {

    Size = 4;

  if (Result != MCDisassembler::Fail)

    return Result;

  }



  Size = 4;

  return MCDisassembler::Fail;

}

llvm/test/tools/llvm-objdump/Mips/disassemble-all.test

0 → 100644
+16 −0
Original line number Diff line number Diff line 
# RUN: yaml2obj %s | llvm-objdump -D -



# Test that -D does not crash llvm-objdump encounters a section who size is a

# not a multiple of the size of an instruction.



--- !ELF

FileHeader:

  Class:           ELFCLASS64

  Data:            ELFDATA2LSB

  Type:            ET_EXEC

  Machine:         EM_MIPS

Sections:

  - Name:            .note.llvm.crash

    Type:            SHT_NOTE

    Address:         0x0

    Content:         002E746578

llvm/test/tools/llvm-objdump/Mips/lit.local.cfg

0 → 100644
+3 −0
Original line number Diff line number Diff line 
if not 'Mips' in config.root.targets:

    config.unsupported = True