Fixed a sign-extension bug in the X86 disassembler
that was causing PC-relative branch targets to be
evaluated incorrectly. Also added support for
checking operand values to the llvm-mc tester.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103128 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/Disassembler/X86Disassembler.cpp b/lib/Target/X86/Disassembler/X86Disassembler.cpp
index 62e7357..797fd89 100644
--- a/lib/Target/X86/Disassembler/X86Disassembler.cpp
+++ b/lib/Target/X86/Disassembler/X86Disassembler.cpp
@@ -155,7 +155,57 @@
///
/// @param mcInst - The MCInst to append to.
/// @param immediate - The immediate value to append.
-static void translateImmediate(MCInst &mcInst, uint64_t immediate) {
+/// @param operand - The operand, as stored in the descriptor table.
+/// @param insn - The internal instruction.
+static void translateImmediate(MCInst &mcInst,
+ uint64_t immediate,
+ OperandSpecifier &operand,
+ InternalInstruction &insn) {
+ // Sign-extend the immediate if necessary.
+
+ OperandType type = operand.type;
+
+ if (type == TYPE_RELv) {
+ switch (insn.displacementSize) {
+ default:
+ break;
+ case 8:
+ type = TYPE_MOFFS8;
+ break;
+ case 16:
+ type = TYPE_MOFFS16;
+ break;
+ case 32:
+ type = TYPE_MOFFS32;
+ break;
+ case 64:
+ type = TYPE_MOFFS64;
+ break;
+ }
+ }
+
+ switch (type) {
+ case TYPE_MOFFS8:
+ case TYPE_REL8:
+ if(immediate & 0x80)
+ immediate |= ~(0xffull);
+ break;
+ case TYPE_MOFFS16:
+ if(immediate & 0x8000)
+ immediate |= ~(0xffffull);
+ break;
+ case TYPE_MOFFS32:
+ case TYPE_REL32:
+ case TYPE_REL64:
+ if(immediate & 0x80000000)
+ immediate |= ~(0xffffffffull);
+ break;
+ case TYPE_MOFFS64:
+ default:
+ // operand is 64 bits wide. Do nothing.
+ break;
+ }
+
mcInst.addOperand(MCOperand::CreateImm(immediate));
}
@@ -447,8 +497,10 @@
case ENCODING_IO:
case ENCODING_Iv:
case ENCODING_Ia:
- translateImmediate(mcInst,
- insn.immediates[insn.numImmediatesTranslated++]);
+ translateImmediate(mcInst,
+ insn.immediates[insn.numImmediatesTranslated++],
+ operand,
+ insn);
return false;
case ENCODING_RB:
case ENCODING_RW: