[PATCH] [llvm-mc] Fix bad sign extension on callw immediate

[Matthew Barney]

Hi dougk,

An instruction sequence like 0x66 0xe8 0x59 0xcf was incorrectly disassembled due to a missing TYPE_REL16 in the translateImmediate type switch, and resulted in a signed short relative immediate in callw, like 0xcf59, to disassemble to 53081 instead of -12455.

REPOSITORY
  rL LLVM

http://reviews.llvm.org/D9514

Files:
  lib/Target/X86/Disassembler/X86Disassembler.cpp

Index: lib/Target/X86/Disassembler/X86Disassembler.cpp
===================================================================
--- lib/Target/X86/Disassembler/X86Disassembler.cpp
+++ lib/Target/X86/Disassembler/X86Disassembler.cpp
@@ -553,6 +553,12 @@
     if(immediate & 0x80)
       immediate |= ~(0xffull);
     break;
+  case TYPE_REL16:
+    isBranch = true;
+    pcrel = insn.startLocation + insn.immediateOffset + insn.immediateSize;
+    if(immediate & 0x8000)
+      immediate |= ~(0xffffull);
+    break;
   case TYPE_REL32:
   case TYPE_REL64:
     isBranch = true;

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