[x86 disassembler] i386-only mode instructions are not shown as invalid in x86_64

[llvmbot]

Bugzilla Link	10664
Resolution	FIXED
Resolved on	Nov 07, 2018 00:17
Version	trunk
OS	All
Blocks	llvm/llvm-bugzilla-archive#10988
Reporter	LLVM Bugzilla Contributor
CC	@topperc

Extended Description

According to the "Intel® 64 and IA-32 Architectures Software Developer’s Manual
Volume 2 (2A & 2B): Instruction Set Reference, A-Z", p. 3-23:
AAA—ASCII Adjust After Addition
64-bit: Invalid

Using llvm-mc built from trunk revision 135913:
$ echo '0x37'| ./llvm-mc -disassemble -triple="i386" aaa
$ echo '0x37'| ./llvm-mc -disassemble -triple="x86_64" aaa

There are many 32-bit only instructions that are similar to this.

[llvmbot]

These are shown as invalid in 64-bit mode on p. 4-188 of the Intel doc:
$ echo '0x1f'| ./llvm-mc -disassemble -triple="x86_64" -x86-asm-syntax=intel
pop %ds
$ echo '0x07'| ./llvm-mc -disassemble -triple="x86_64" -x86-asm-syntax=intel
pop %es
$ echo '0x17'| ./llvm-mc -disassemble -triple="x86_64" -x86-asm-syntax=intel
pop %ss

[topperc]

Fixed in r140370.

[llvmbot]

All of these cases appear to be fixed with llvm-mc built from r140997.

[bcardosolopes]

mentioned in issue llvm/llvm-bugzilla-archive#10988