Fix the x86 disassembler to at least print the lock prefix if it is the first

[oota-llvm.git] / lib / Target / X86 / Disassembler / X86DisassemblerDecoder.c

diff --git a/lib/Target/X86/Disassembler/X86DisassemblerDecoder.c b/lib/Target/X86/Disassembler/X86DisassemblerDecoder.c
index e055773750f114a81cc02902e653c395b4ebecd3..6f7e8f234660022cb921fc658fa2a8499e068f0f 100644 (file)
--- a/lib/Target/X86/Disassembler/X86DisassemblerDecoder.c
+++ b/lib/Target/X86/Disassembler/X86DisassemblerDecoder.c
@@ -312,6 +312,13 @@ static int readPrefixes(struct InternalInstruction* insn) {
     
     if (consumeByte(insn, &byte))
       return -1;
+
+    // If the the first byte is a LOCK prefix break and let it be disassembled
+    // as a lock "instruction", by creating an <MCInst #xxxx LOCK_PREFIX>.
+    // FIXME there is currently no way to get the disassembler to print the
+    // lock prefix if it is not the first byte.
+    if (insn->readerCursor - 1 == insn->startLocation && byte == 0xf0)
+      break;
     
     switch (byte) {
     case 0xf0:  /* LOCK */
@@ -763,6 +770,8 @@ static int getID(struct InternalInstruction* insn, void *miiArg) {
   else {
     if (isPrefixAtLocation(insn, 0x66, insn->necessaryPrefixLocation))
       attrMask |= ATTR_OPSIZE;
+    else if (isPrefixAtLocation(insn, 0x67, insn->necessaryPrefixLocation))
+      attrMask |= ATTR_ADSIZE;
     else if (isPrefixAtLocation(insn, 0xf3, insn->necessaryPrefixLocation))
       attrMask |= ATTR_XS;
     else if (isPrefixAtLocation(insn, 0xf2, insn->necessaryPrefixLocation))
@@ -1014,6 +1023,7 @@ static int readDisplacement(struct InternalInstruction* insn) {
     return 0;
   
   insn->consumedDisplacement = TRUE;
+  insn->displacementOffset = insn->readerCursor - insn->startLocation;
   
   switch (insn->eaDisplacement) {
   case EA_DISP_NONE:
@@ -1410,6 +1420,7 @@ static int readImmediate(struct InternalInstruction* insn, uint8_t size) {
     size = insn->immediateSize;
   else
     insn->immediateSize = size;
+  insn->immediateOffset = insn->readerCursor - insn->startLocation;
   
   switch (size) {
   case 1: