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

[m4b]

Summary

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.

[dougk]

add test please, perhaps next to the 'callw' test in test/MC/Disassembler/X86/x86-16.txt

[m4b]

I added the unit tests as a separate commit; I was unsure what the protocol is in this case. Just in case, I've added the same diff in this comment.

diff --git a/test/MC/Disassembler/X86/x86-32.txt b/test/MC/Disassembler/X86/x86-32.txt
index 830b830..aaf9e5b 100644
--- a/test/MC/Disassembler/X86/x86-32.txt
+++ b/test/MC/Disassembler/X86/x86-32.txt
@@ -54,6 +54,12 @@
 # CHECK: calll -1234
 0xe8 0x2e 0xfb 0xff 0xff
 
+# CHECK: callw -1
+0x66 0xe8 0xff 0xff
+
+# CHECK: callw 32767
+0x66 0xe8 0xff 0x7f
+
 # CHECK: lfence
 0x0f 0xae 0xe8
 
diff --git a/test/MC/Disassembler/X86/x86-64.txt b/test/MC/Disassembler/X86/x86-64.txt
index f000d15..3088619 100644
--- a/test/MC/Disassembler/X86/x86-64.txt
+++ b/test/MC/Disassembler/X86/x86-64.txt
@@ -301,3 +301,9 @@
 
 # CHECK: movq %rax, 1515870810
 0x67, 0x48 0xa3 0x5a 0x5a 0x5a 0x5a
+
+# CHECK: callq -32769
+0xe8 0xff 0x7f 0xff 0xff
+
+# CHECK: callq 32767
+0xe8 0xff 0x7f 0x00 0x00

[m4b]

added unit tests for 16, 32, and 64 bit CALL disassembly.

[m4b]

[llvm-mc] final commit with unit tests and callw fix for 32-bit mode

[m4b]

*ping* This patch has been sitting for over a month. I don't have push rights; someone else needs to land it.

[dougk]

Sorry, didn't know you didn't have commit. I'll do this.

lib/Target/X86/Disassembler/X86Disassembler.cpp

case TYPE_XMM512:
     mcInst.addOperand(MCOperand::CreateReg(X86::ZMM0 + (immediate >> 4)));
     return;
   case TYPE_REL8:
     isBranch = true;
     pcrel = insn.startLocation + insn.immediateOffset + insn.immediateSize;
     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;
     pcrel = insn.startLocation + insn.immediateOffset + insn.immediateSize;
     if(immediate & 0x80000000)
       immediate |= ~(0xffffffffull);
     break;
   default:

test/MC/Disassembler/X86/x86-16.txt

 0x66 0xc3
 
 # CHECK: lretw
 0xcb
 
 # CHECK: lretl
 0x66 0xcb
 
+# CHECK: callw  -1
+0xe8 0xff 0xff

test/MC/Disassembler/X86/x86-32.txt

 
 
 # CHECK: addb %al, (%eax)
 0 0
 
 # CHECK: calll  -1234
 0xe8 0x2e 0xfb 0xff 0xff
 
+# CHECK: callw  -1
+0x66 0xe8 0xff 0xff
+
 # CHECK: lfence
 0x0f 0xae 0xe8
 
 # CHECK: mfence
 0x0f 0xae 0xf0
 
 # CHECK: monitor
 0x0f 0x01 0xc8

test/MC/Disassembler/X86/x86-64.txt

 # CHECK: movq 1515870810, %rax
 0x67, 0x48 0xa1 0x5a 0x5a 0x5a 0x5a
 
 # CHECK: movabsq %rax, 6510615555426900570
 0x48 0xa3 0x5a 0x5a 0x5a 0x5a 0x5a 0x5a 0x5a 0x5a
 
 # CHECK: movq %rax, 1515870810
 0x67, 0x48 0xa3 0x5a 0x5a 0x5a 0x5a
+
+# CHECK: callq 32767
+0xe8 0xff 0x7f 0x00 0x00
+
+# CHECK: callq -32769
+0xe8 0xff 0x7f 0xff 0xff