digitalmars.D.bugs - [Issue 11310] New: Alignment failure in test42.d
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http://d.puremagic.com/issues/show_bug.cgi?id=11310
Summary: Alignment failure in test42.d
Product: D
Version: D2
Platform: x86_64
OS/Version: Linux
Status: NEW
Severity: normal
Priority: P2
Component: DMD
AssignedTo: nobody puremagic.com
ReportedBy: bugzilla digitalmars.com
22:43:57 PDT ---
Here's the code that fails in test/runnable/test42.d:
-----------------------------
align(16) struct S41
{
int[4] a;
}
shared int x41;
shared S41 s41;
void test41()
{
printf("&x = %p\n", &x41);
printf("&s = %p\n", &s41);
assert((cast(int)&s41 & 0xF) == 0);
}
----------------------------
when compiled on Linux with:
-O -fPIC
Curiously, it prints:
&x = 0x7fef00
&s = 0x7fef10
which shows it is aligned correctly - so why does the assert fail?
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Oct 20 2013
d-bugmail puremagic.com
http://d.puremagic.com/issues/show_bug.cgi?id=11310
safety0ff.bugz <safety0ff.bugz gmail.com> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |safety0ff.bugz gmail.com
00:01:04 PDT ---
I noticed importing random stuff (e.g. std.string, std.stdio, std.algorithm)
made it run without error, then I looked at the assembly code:
Disassembly of section .text._D6_113106test41FZv:
0000000000000000 <_D6_113106test41FZv>:
0: 55 push %rbp
1: 48 8b ec mov %rsp,%rbp
4: f6 05 00 00 00 00 0f testb $0xf,0x0(%rip)
b: 74 0a je 17 <_D6_113106test41FZv+0x17>
d: bf 11 00 00 00 mov $0x11,%edi
12: e8 00 00 00 00 callq 17 <_D6_113106test41FZv+0x17>
17: 5d pop %rbp
18: c3 retq
19: 0f 1f 80 00 00 00 00 nopl 0x0(%rax)
Looks like it is and'ing the instruction pointer with 0xf.
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Oct 21 2013
http://d.puremagic.com/issues/show_bug.cgi?id=11310 00:03:26 PDT --- That is the assembly without printf's, btw. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Oct 21 2013
http://d.puremagic.com/issues/show_bug.cgi?id=11310 12:13:18 PDT --- Created an attachment (id=1273) Edb screenshot for second printf -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Oct 21 2013
http://d.puremagic.com/issues/show_bug.cgi?id=11310 12:13:49 PDT --- Created an attachment (id=1274) Edb screenshot for assert test -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Oct 21 2013
http://d.puremagic.com/issues/show_bug.cgi?id=11310 12:20:33 PDT --- As you can see in the first screen shot, the address for s41 is calculated properly, whereas in the second screenshot the is a mistake. rip for the printf calculation: 0x419c84 rip for the assert calculation: 0x419c99 difference: 0x15 offset for the printf calculation: 0x21e35c offset for the assert calculation: 0x21e344 difference: 0x18 Looking at the relocation section of the executable, printf seems to be giving the correct location (0x63cdd0.) -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Oct 21 2013
http://d.puremagic.com/issues/show_bug.cgi?id=11310 12:59:27 PDT --- Looking at the non-optimized version of the code, the test instruction operates on dwords, which makes the constant 3 bytes longer (i.e. the difference noted in comment 5,) the constant off of rip is the same as before. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Oct 21 2013
http://d.puremagic.com/issues/show_bug.cgi?id=11310 22:25:39 PDT --- Created an attachment (id=1279) Edb screenshot for unoptimized version Just to make it more clear what the issue is (I was quite sick when I wrote the other comment): The code responsible for calculating the offsets from the IP to the offset table is calculating an offset that is off by 3 bytes. This offset is appropriate for the instruction present in the unoptimized version which operates on dword. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Oct 22 2013
http://d.puremagic.com/issues/show_bug.cgi?id=11310 05:52:16 PDT --- Created an attachment (id=1280) This hack makes the program run properly for me I don't know if there are cases where this will produce invalid code, I'll pull out the 64 bit architecture manual tonight and figure it out. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Oct 23 2013
http://d.puremagic.com/issues/show_bug.cgi?id=11310
safety0ff.bugz <safety0ff.bugz gmail.com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |pull
11:52:46 PDT ---
After checking manuals, I've concluded that this is the correct fix and I've
submitted a pull request:
https://github.com/D-Programming-Language/dmd/pull/2691
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Oct 23 2013
http://d.puremagic.com/issues/show_bug.cgi?id=11310 Commits pushed to master at https://github.com/D-Programming-Language/dmd https://github.com/D-Programming-Language/dmd/commit/6ec2800443a088b42722b1580a3388111ed9c2ab fix Issue 11310 - Fix RIP relative offset calculation for TEST instruction. https://github.com/D-Programming-Language/dmd/commit/5138bc4a1aa09e935875c7343adeee3def5ca21c fix Issue 11310 - Fix RIP relative offset calculation for TEST instruction -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Oct 24 2013
http://d.puremagic.com/issues/show_bug.cgi?id=11310 Commit pushed to 2.064 at https://github.com/D-Programming-Language/dmd https://github.com/D-Programming-Language/dmd/commit/6edfd4cdd96889dd539f4b888fcf7e1bd70e09a1 fix Issue 11310 - Fix RIP relative offset calculation for TEST instruction -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Oct 24 2013
http://d.puremagic.com/issues/show_bug.cgi?id=11310
Walter Bright <bugzilla digitalmars.com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Resolution| |FIXED
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Oct 24 2013