 | Posted by Brian Callahan |  Permalink Reply |
|
Brian Callahan 
| https://issues.dlang.org/show_bug.cgi?id=22656
Brian Callahan <bcallah@openbsd.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |bcallah@openbsd.org
--- Comment #1 from Brian Callahan <bcallah@openbsd.org> ---
I think it may be the prefix; I can trigger this issue reliably with plain ol' leas and calls using code from my Intel 8080 assembler. But like you, it's that 66 prefix causing issues:
Code in question:
```
import std.stdio;
import std.range;
string label;
string argument1, argument2;
void title()
{
if ((label.empty && !argument1.empty && !argument2.empty) == false)
stderr.writeln("argument check failed");
}
```
Relevant -vasm output:
```
_D4vasm5titleFZv:
0000: 55 push RBP
0001: 48 8B EC mov RBP,RSP
0004:66 48 8D 3D FC FF FF FF lea RDI,[0FFFFFFFCh][RIP]
000c:66 66 48 E8 00 00 00 00 call L0
0014: 48 89 C7 mov RDI,RAX
0017: E8 00 00 00 00 call L0
001c: 84 C0 test AL,AL
001e: 74 38 je L58
0020:66 48 8D 3D FC FF FF FF lea RDI,[0FFFFFFFCh][RIP]
0028:66 66 48 E8 00 00 00 00 call L0
0030: 48 89 C7 mov RDI,RAX
0033: E8 00 00 00 00 call L0
0038: 34 01 xor AL,1
003a: 74 1C je L58
003c:66 48 8D 3D FC FF FF FF lea RDI,[0FFFFFFFCh][RIP]
0044:66 66 48 E8 00 00 00 00 call L0
004c: 48 89 C7 mov RDI,RAX
004f: E8 00 00 00 00 call L0
0054: 34 01 xor AL,1
0056: 75 04 jne L5c
0058: 31 C0 xor EAX,EAX
005a: EB 05 jmp short L61
005c: B8 01 00 00 00 mov EAX,1
0061: A8 01 test AL,1
0063: 75 19 jne L7e
0065: E8 00 00 00 00 call L0
006a: 48 8D 15 FC FF FF FF lea RDX,[0FFFFFFFCh][RIP]
0071: BE 15 00 00 00 mov EAX,015h
0076: 48 89 C7 mov RDI,RAX
0079: E8 00 00 00 00 call L0
007e: 5D pop RBP
007f: C3 ret
```
Here's GNU objdump for comparison:
```
0000000000000000 <_D4vasm5titleFZv>:
0: 55 push %rbp
1: 48 8b ec mov %rsp,%rbp
4: 66 48 8d 3d 00 00 00 data16 lea 0x0(%rip),%rdi # c
<_D4vasm5titleFZv+0xc>
b: 00
c: 66 66 48 e8 00 00 00 data16 data16 rex.W call 14
<_D4vasm5titleFZv+0x14>
13: 00
14: 48 89 c7 mov %rax,%rdi
17: e8 00 00 00 00 call 1c <_D4vasm5titleFZv+0x1c>
1c: 84 c0 test %al,%al
1e: 74 38 je 58 <_D4vasm5titleFZv+0x58>
20: 66 48 8d 3d 00 00 00 data16 lea 0x0(%rip),%rdi # 28
<_D4vasm5titleFZv+0x28>
27: 00
28: 66 66 48 e8 00 00 00 data16 data16 rex.W call 30
<_D4vasm5titleFZv+0x30>
2f: 00
30: 48 89 c7 mov %rax,%rdi
33: e8 00 00 00 00 call 38 <_D4vasm5titleFZv+0x38>
38: 34 01 xor $0x1,%al
3a: 74 1c je 58 <_D4vasm5titleFZv+0x58>
3c: 66 48 8d 3d 00 00 00 data16 lea 0x0(%rip),%rdi # 44
<_D4vasm5titleFZv+0x44>
43: 00
44: 66 66 48 e8 00 00 00 data16 data16 rex.W call 4c
<_D4vasm5titleFZv+0x4c>
4b: 00
4c: 48 89 c7 mov %rax,%rdi
4f: e8 00 00 00 00 call 54 <_D4vasm5titleFZv+0x54>
54: 34 01 xor $0x1,%al
56: 75 04 jne 5c <_D4vasm5titleFZv+0x5c>
58: 31 c0 xor %eax,%eax
5a: eb 05 jmp 61 <_D4vasm5titleFZv+0x61>
5c: b8 01 00 00 00 mov $0x1,%eax
61: a8 01 test $0x1,%al
63: 75 19 jne 7e <_D4vasm5titleFZv+0x7e>
65: e8 00 00 00 00 call 6a <_D4vasm5titleFZv+0x6a>
6a: 48 8d 15 00 00 00 00 lea 0x0(%rip),%rdx # 71
<_D4vasm5titleFZv+0x71>
71: be 15 00 00 00 mov $0x15,%esi
76: 48 89 c7 mov %rax,%rdi
79: e8 00 00 00 00 call 7e <_D4vasm5titleFZv+0x7e>
7e: 5d pop %rbp
7f: c3 ret
```
llvm-objdump looks a bit nicer:
```
0000000000000000 <_D4vasm5titleFZv>:
0: 55 pushq %rbp
1: 48 8b ec movq %rsp, %rbp
4: 66 48 8d 3d 00 00 00 00 leaq (%rip), %rdi # 0xc
<_D4vasm5titleFZv+0xc>
c: 66 66 48 e8 00 00 00 00 callq 0x14 <_D4vasm5titleFZv+0x14>
14: 48 89 c7 movq %rax, %rdi
17: e8 00 00 00 00 callq 0x1c <_D4vasm5titleFZv+0x1c>
1c: 84 c0 testb %al, %al
1e: 74 38 je 0x58 <_D4vasm5titleFZv+0x58>
20: 66 48 8d 3d 00 00 00 00 leaq (%rip), %rdi # 0x28
<_D4vasm5titleFZv+0x28>
28: 66 66 48 e8 00 00 00 00 callq 0x30 <_D4vasm5titleFZv+0x30>
30: 48 89 c7 movq %rax, %rdi
33: e8 00 00 00 00 callq 0x38 <_D4vasm5titleFZv+0x38>
38: 34 01 xorb $1, %al
3a: 74 1c je 0x58 <_D4vasm5titleFZv+0x58>
3c: 66 48 8d 3d 00 00 00 00 leaq (%rip), %rdi # 0x44
<_D4vasm5titleFZv+0x44>
44: 66 66 48 e8 00 00 00 00 callq 0x4c <_D4vasm5titleFZv+0x4c>
4c: 48 89 c7 movq %rax, %rdi
4f: e8 00 00 00 00 callq 0x54 <_D4vasm5titleFZv+0x54>
54: 34 01 xorb $1, %al
56: 75 04 jne 0x5c <_D4vasm5titleFZv+0x5c>
58: 31 c0 xorl %eax, %eax
5a: eb 05 jmp 0x61 <_D4vasm5titleFZv+0x61>
5c: b8 01 00 00 00 movl $1, %eax
61: a8 01 testb $1, %al
63: 75 19 jne 0x7e <_D4vasm5titleFZv+0x7e>
65: e8 00 00 00 00 callq 0x6a <_D4vasm5titleFZv+0x6a>
6a: 48 8d 15 00 00 00 00 leaq (%rip), %rdx # 0x71
<_D4vasm5titleFZv+0x71>
71: be 15 00 00 00 movl $21, %esi
76: 48 89 c7 movq %rax, %rdi
79: e8 00 00 00 00 callq 0x7e <_D4vasm5titleFZv+0x7e>
7e: 5d popq %rbp
7f: c3 retq
```
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