diff options
Diffstat (limited to 'lib/Target/ARM/Disassembler/ARMDisassembler.cpp')
| -rw-r--r-- | lib/Target/ARM/Disassembler/ARMDisassembler.cpp | 28 |
1 files changed, 23 insertions, 5 deletions
diff --git a/lib/Target/ARM/Disassembler/ARMDisassembler.cpp b/lib/Target/ARM/Disassembler/ARMDisassembler.cpp index 04313400b8d9d..47c31043d9c05 100644 --- a/lib/Target/ARM/Disassembler/ARMDisassembler.cpp +++ b/lib/Target/ARM/Disassembler/ARMDisassembler.cpp @@ -380,11 +380,18 @@ bool ARMDisassembler::getInstruction(MCInst &MI, raw_ostream &os) const { // The machine instruction. uint32_t insn; + uint8_t bytes[4]; // We want to read exactly 4 bytes of data. - if (Region.readBytes(Address, 4, (uint8_t*)&insn, NULL) == -1) + if (Region.readBytes(Address, 4, (uint8_t*)bytes, NULL) == -1) return false; + // Encoded as a small-endian 32-bit word in the stream. + insn = (bytes[3] << 24) | + (bytes[2] << 16) | + (bytes[1] << 8) | + (bytes[0] << 0); + unsigned Opcode = decodeARMInstruction(insn); ARMFormat Format = ARMFormats[Opcode]; Size = 4; @@ -414,9 +421,15 @@ bool ThumbDisassembler::getInstruction(MCInst &MI, const MemoryObject &Region, uint64_t Address, raw_ostream &os) const { - // The machine instruction. + // The Thumb instruction stream is a sequence of halhwords. + + // This represents the first halfword as well as the machine instruction + // passed to decodeThumbInstruction(). For 16-bit Thumb instruction, the top + // halfword of insn is 0x00 0x00; otherwise, the first halfword is moved to + // the top half followed by the second halfword. uint32_t insn = 0; - uint32_t insn1 = 0; + // Possible second halfword. + uint16_t insn1 = 0; // A6.1 Thumb instruction set encoding // @@ -429,9 +442,12 @@ bool ThumbDisassembler::getInstruction(MCInst &MI, // Otherwise, the halfword is a 16-bit instruction. // Read 2 bytes of data first. - if (Region.readBytes(Address, 2, (uint8_t*)&insn, NULL) == -1) + uint8_t bytes[2]; + if (Region.readBytes(Address, 2, (uint8_t*)bytes, NULL) == -1) return false; + // Encoded as a small-endian 16-bit halfword in the stream. + insn = (bytes[1] << 8) | bytes[0]; unsigned bits15_11 = slice(insn, 15, 11); bool IsThumb2 = false; @@ -439,8 +455,10 @@ bool ThumbDisassembler::getInstruction(MCInst &MI, // { 0b11101 /* 0x1D */, 0b11110 /* 0x1E */, ob11111 /* 0x1F */ }. if (bits15_11 == 0x1D || bits15_11 == 0x1E || bits15_11 == 0x1F) { IsThumb2 = true; - if (Region.readBytes(Address + 2, 2, (uint8_t*)&insn1, NULL) == -1) + if (Region.readBytes(Address + 2, 2, (uint8_t*)bytes, NULL) == -1) return false; + // Encoded as a small-endian 16-bit halfword in the stream. + insn1 = (bytes[1] << 8) | bytes[0]; insn = (insn << 16 | insn1); } |