[PATCH] D95682: [X86] Fix disassembly of x86-64 GDTLS code sequence

[Andrew Ng via Phabricator via llvm-commits]

andrewng created this revision.
andrewng added reviewers: craig.topper, MaskRay.
Herald added subscribers: pengfei, rupprecht, hiraditya.
Herald added a reviewer: jhenderson.
andrewng requested review of this revision.
Herald added a project: LLVM.

For x86-64 the REX.w prefix takes precedence over any other size
override (i.e. 0x66). Therefore, for x86-64 when REX.w is present set
'hasOpSize' to false to ensure that any size override is ignored.

Fixes PR48901.


https://reviews.llvm.org/D95682

Files:
  llvm/lib/Target/X86/Disassembler/X86Disassembler.cpp
  llvm/test/MC/Disassembler/X86/x86-64.txt
  llvm/test/tools/llvm-objdump/X86/disassemble-gdtls.s


Index: llvm/test/tools/llvm-objdump/X86/disassemble-gdtls.s
===================================================================
--- /dev/null
+++ llvm/test/tools/llvm-objdump/X86/disassemble-gdtls.s
@@ -0,0 +1,18 @@
+# RUN: llvm-mc %s -filetype=obj -triple=x86_64-pc-linux | llvm-objdump -d - | FileCheck %s
+
+# CHECK:      <foo>:
+# CHECK-NEXT: 0: 66 48 8d 3d 00 00 00 00       leaq    (%rip), %rdi  # 8 <foo+0x8>
+# CHECK-NEXT: 8: 66 66 48 e8 00 00 00 00       callq   0x10 <foo+0x10>
+# CHECK-EMPTY:
+
+foo:
+ data16
+ leaq   bar at TLSGD(%rip),%rdi
+ data16
+ data16
+ rex64
+ callq  __tls_get_addr at PLT
+
+.section .tdata,"awT", at progbits
+bar:
+.long 42
Index: llvm/test/MC/Disassembler/X86/x86-64.txt
===================================================================
--- llvm/test/MC/Disassembler/X86/x86-64.txt
+++ llvm/test/MC/Disassembler/X86/x86-64.txt
@@ -329,8 +329,8 @@
 # CHECK: callw 32767
 0x66 0xe8 0xff 0x7f
 
-# CHECK: callw 32767
-0x66 0x66 0x48 0xe8 0xff 0x7f
+# CHECK: callq 32767
+0x66 0x66 0x48 0xe8 0xff 0x7f 0x00 0x00
 
 # CHECK: jmp -32769
 0xe9 0xff 0x7f 0xff 0xff
@@ -339,7 +339,7 @@
 0x66 0xe9 0xff 0x7f
 
 # CHECK: jmp 32767
-0x66 0x66 0x48 0xe9 0xff 0x7f
+0x66 0x66 0x48 0xe9 0xff 0x7f 0x00 0x00
 
 # CHECK: jo -32769
 0x0f 0x80 0xff 0x7f 0xff 0xff
Index: llvm/lib/Target/X86/Disassembler/X86Disassembler.cpp
===================================================================
--- llvm/lib/Target/X86/Disassembler/X86Disassembler.cpp
+++ llvm/lib/Target/X86/Disassembler/X86Disassembler.cpp
@@ -492,6 +492,7 @@
       insn->addressSize = (insn->hasAdSize ? 4 : 8);
       insn->displacementSize = 4;
       insn->immediateSize = 4;
+      insn->hasOpSize = false;
     } else {
       insn->registerSize = (insn->hasOpSize ? 2 : 4);
       insn->addressSize = (insn->hasAdSize ? 4 : 8);


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