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authorRichard Mitton <richard@codersnotes.com>2013-08-30 21:19:48 +0000
committerRichard Mitton <richard@codersnotes.com>2013-08-30 21:19:48 +0000
commit576ee003d0f53df9a2091741d881d79a05a70ca6 (patch)
tree9d3164ebcd8834087bc547ec13e8da54546dbf7a /llvm/lib/Target/X86/Disassembler/X86DisassemblerDecoder.c
parent2865be79f897e01fe62bb9c0ff3d541acf873e4f (diff)
downloadbcm5719-llvm-576ee003d0f53df9a2091741d881d79a05a70ca6.tar.gz
bcm5719-llvm-576ee003d0f53df9a2091741d881d79a05a70ca6.zip
Fixed a bug where diassembling an instruction that had a prefix would cause LLVM to identify a 1-byte instruction, but then upon querying it for that 1-byte instruction would cause an undefined opcode.
llvm-svn: 189698
Diffstat (limited to 'llvm/lib/Target/X86/Disassembler/X86DisassemblerDecoder.c')
-rw-r--r--llvm/lib/Target/X86/Disassembler/X86DisassemblerDecoder.c16
1 files changed, 9 insertions, 7 deletions
diff --git a/llvm/lib/Target/X86/Disassembler/X86DisassemblerDecoder.c b/llvm/lib/Target/X86/Disassembler/X86DisassemblerDecoder.c
index bb195ee3140..b63fd5aee3c 100644
--- a/llvm/lib/Target/X86/Disassembler/X86DisassemblerDecoder.c
+++ b/llvm/lib/Target/X86/Disassembler/X86DisassemblerDecoder.c
@@ -314,20 +314,22 @@ static int readPrefixes(struct InternalInstruction* insn) {
while (isPrefix) {
prefixLocation = insn->readerCursor;
+ /* If we fail reading prefixes, just stop here and let the opcode reader deal with it */
if (consumeByte(insn, &byte))
- return -1;
+ break;
/*
* If the byte is a LOCK/REP/REPNE prefix and not a part of the opcode, then
* break and let it be disassembled as a normal "instruction".
*/
+ if (insn->readerCursor - 1 == insn->startLocation && byte == 0xf0)
+ break;
+
+ uint8_t nextByte;
if (insn->readerCursor - 1 == insn->startLocation
- && (byte == 0xf0 || byte == 0xf2 || byte == 0xf3)) {
- uint8_t nextByte;
- if (byte == 0xf0)
- break;
- if (lookAtByte(insn, &nextByte))
- return -1;
+ && (byte == 0xf2 || byte == 0xf3)
+ && !lookAtByte(insn, &nextByte))
+ {
/*
* If the byte is 0xf2 or 0xf3, and any of the following conditions are
* met:
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