llvm dev - May 2016 - [BUG] Mismatch between assembler & disassembler of X86 RIP-relative instruction

Hi,

I found a mismatch between assembler & disassembler of X86: I assembled an
instruction, then disassembled the output, but the result is not the same
as the first original code: "add qword ptr [205163983024656], 1" vs
" add
qword ptr [1985229328], 1"

Anybody knows what is wrong?

Thanks.


$ echo "ADD QWORD PTR [0xba9876543210], 0x1"|llvm-mc -assemble
-triple=x86_64 -x86-asm-syntax=intel -output-asm-variant=1
--show-encoding
    add    qword ptr [205163983024656], 1 #
encoding:[0x48,0x83,0x04,0x25,0x10,0x32,0x54,0x76,0x01]

$ echo "0x48,0x83,0x04,0x25,0x10,0x32,0x54,0x76,0x01"|llvm-mc
-disassemble
-triple=x86_64 -x86-asm-syntax=intel -output-asm-variant=1 --show-encoding
    add    qword ptr [1985229328], 1 # encoding:
[0x48,0x83,0x04,0x25,0x10,0x32,0x54,0x76,0x01]
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On Mon, May 23, 2016 at 2:44 PM, Jun Koi <junkoi2004 at gmail.com> wrote:
> Hi,
>
> I found a mismatch between assembler & disassembler of X86: I assembled
an
> instruction, then disassembled the output, but the result is not the same
> as the first original code: "add qword ptr [205163983024656], 1"
vs " add
> qword ptr [1985229328], 1"
>
> Anybody knows what is wrong?
>
> Thanks.
>
>
> $ echo "ADD QWORD PTR [0xba9876543210], 0x1"|llvm-mc -assemble
> -triple=x86_64 -x86-asm-syntax=intel -output-asm-variant=1
> --show-encoding
>     add    qword ptr [205163983024656], 1 #
> encoding:[0x48,0x83,0x04,0x25,0x10,0x32,0x54,0x76,0x01]
>
> $ echo "0x48,0x83,0x04,0x25,0x10,0x32,0x54,0x76,0x01"|llvm-mc
-disassemble
> -triple=x86_64 -x86-asm-syntax=intel -output-asm-variant=1 --show-encoding
>     add    qword ptr [1985229328], 1 # encoding:
> [0x48,0x83,0x04,0x25,0x10,0x32,0x54,0x76,0x01]
>
To make it more clear, here is the same thing again, but with hexa
immediate. You can see the difference in memory address: 0xba9876543210 vs
0x76543210.


$ echo "ADD QWORD PTR [0xba9876543210], 0x1"|llvm-mc -assemble
-triple=x86_64 -x86-asm-syntax=intel -output-asm-variant=1 --show-encoding
-print-imm-hex
    .text
    add    qword ptr [0xba9876543210], 0x1 # encoding:
[0x48,0x83,0x04,0x25,0x10,0x32,0x54,0x76,0x01]


$ echo "0x48,0x83,0x04,0x25,0x10,0x32,0x54,0x76,0x01"|llvm-mc
-disassemble
-triple=x86_64 -x86-asm-syntax=intel -output-asm-variant=1 --show-encoding
-print-imm-hex
    .text
    add    qword ptr [0x76543210], 0x1 # encoding:
[0x48,0x83,0x04,0x25,0x10,0x32,0x54,0x76,0x01]
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Hi Jun,

Could you file a PR please?

Thanks,
-Quentin
> On May 22, 2016, at 11:54 PM, Jun Koi via llvm-dev <llvm-dev at
lists.llvm.org> wrote:
> 
> 
> 
> On Mon, May 23, 2016 at 2:44 PM, Jun Koi <junkoi2004 at gmail.com
<mailto:junkoi2004 at gmail.com>> wrote:
> Hi,
> 
> I found a mismatch between assembler & disassembler of X86: I assembled
an instruction, then disassembled the output, but the result is not the same as
the first original code: "add qword ptr [205163983024656], 1" vs
" add qword ptr [1985229328], 1"
> 
> Anybody knows what is wrong?
> 
> Thanks.
> 
> 
> $ echo "ADD QWORD PTR [0xba9876543210], 0x1"|llvm-mc -assemble
-triple=x86_64 -x86-asm-syntax=intel -output-asm-variant=1 --show-encoding
>     add    qword ptr [205163983024656], 1 #
encoding:[0x48,0x83,0x04,0x25,0x10,0x32,0x54,0x76,0x01]
> 
> $ echo "0x48,0x83,0x04,0x25,0x10,0x32,0x54,0x76,0x01"|llvm-mc
-disassemble -triple=x86_64 -x86-asm-syntax=intel -output-asm-variant=1
--show-encoding
>     add    qword ptr [1985229328], 1 # encoding:
[0x48,0x83,0x04,0x25,0x10,0x32,0x54,0x76,0x01]
> 
> To make it more clear, here is the same thing again, but with hexa
immediate. You can see the difference in memory address: 0xba9876543210 vs
0x76543210.
> 
> 
> $ echo "ADD QWORD PTR [0xba9876543210], 0x1"|llvm-mc -assemble
-triple=x86_64 -x86-asm-syntax=intel -output-asm-variant=1 --show-encoding
-print-imm-hex
>     .text
>     add    qword ptr [0xba9876543210], 0x1 # encoding:
[0x48,0x83,0x04,0x25,0x10,0x32,0x54,0x76,0x01]
> 
> 
> $ echo "0x48,0x83,0x04,0x25,0x10,0x32,0x54,0x76,0x01"|llvm-mc
-disassemble -triple=x86_64 -x86-asm-syntax=intel -output-asm-variant=1
--show-encoding -print-imm-hex
>     .text
>     add    qword ptr [0x76543210], 0x1 # encoding:
[0x48,0x83,0x04,0x25,0x10,0x32,0x54,0x76,0x01]
> 
> 
> 
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