[Issue 21038] Wrong codegen when calling wcslen

Jul 11, 2020

Aug 07, 2020

https://issues.dlang.org/show_bug.cgi?id=21038 ag0aep6g <ag0aep6g@gmail.com> changed: What |Removed |Added ---------------------------------------------------------------------------- Keywords| |wrong-code CC| |ag0aep6g@gmail.com --- Comment #1 from ag0aep6g <ag0aep6g@gmail.com> --- The string data is getting misaligned. wcslen assumes properly aligned data. testabcd.d can be reduced to this: ---- alias wchar_t = dchar; const(wchar_t)* name = "abcd"; void test() { assert((cast(size_t) name) % wchar_t.sizeof == 0); /* Fails. Should pass. */ } ---- --

August 07, 2020

[Issue 21038] Wrong codegen when calling wcslen

Posted by Walter Bright

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Walter Bright

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https://issues.dlang.org/show_bug.cgi?id=21038

Walter Bright <bugzilla@digitalmars.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |bugzilla@digitalmars.com

--- Comment #2 from Walter Bright <bugzilla@digitalmars.com> ---
For the program:

alias wchar_t = dchar;
const(wchar_t)* x = "xz";
const(wchar_t)* name = "abcd";
void test()
{
    assert((cast(size_t) name) % wchar_t.sizeof == 0); /* Fails. Should pass.
*/
}

the output generated is:

Section 6  .rodata  PROGBITS,ALLOC,SIZE=0x0030(48),OFFSET=0x0040,ALIGN=16
 0040:  78  0  0  0 7a  0  0  0  0  0  0  0 61  0  0  0   x...z.......a...
 0050:  62  0  0  0 63  0  0  0 64  0  0  0  0  0  0  0   b...c...d.......
 0060:   4 10  0  0  0  0  0  0 74 65 73 74  0  0  0  0   ........test....

It's a surprise to me that a 4 byte element array is supposed to be aligned to 8 bytes. I'm not seeing where this is a requirement?

--

https://issues.dlang.org/show_bug.cgi?id=21038 --- Comment #3 from Walter Bright <bugzilla@digitalmars.com> --- Oh, I see now. For: alias wchar_t = dchar; const(wchar)* x = "xz"; const(wchar_t)* name = "abcd"; void test() { assert((cast(size_t) name) % wchar_t.sizeof == 0); /* Fails. Should pass. */ } the result is: Section 6 .rodata PROGBITS,ALLOC,SIZE=0x0030(48),OFFSET=0x0040,ALIGN=16 0040: 78 0 7a 0 0 0 61 0 0 0 62 0 0 0 63 0 x.z...a...b...c. 0050: 0 0 64 0 0 0 0 0 0 0 0 0 0 0 0 0 ..d............. 0060: 4 10 0 0 0 0 0 0 74 65 73 74 0 0 0 0 ........test.... which is wrongly aligned on a 2 byte boundary. --

https://issues.dlang.org/show_bug.cgi?id=21038 Dlang Bot <dlang-bot@dlang.rocks> changed: What |Removed |Added ---------------------------------------------------------------------------- Keywords| |pull --- Comment #4 from Dlang Bot <dlang-bot@dlang.rocks> --- @WalterBright created dlang/dmd pull request #11528 "fix Issue 21038 - wchar and dchar string alignment should be 2 and 4,…" fixing this issue: - fix Issue 21038 - wchar and dchar string alignment should be 2 and 4, respectively https://github.com/dlang/dmd/pull/11528 --

https://issues.dlang.org/show_bug.cgi?id=21038 Dlang Bot <dlang-bot@dlang.rocks> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |RESOLVED Resolution|--- |FIXED --- Comment #5 from Dlang Bot <dlang-bot@dlang.rocks> --- dlang/dmd pull request #11528 "fix Issue 21038 - wchar and dchar string alignment should be 2 and 4,…" was merged into master: - 46994f578813b365050ce19ed0e0bcc132e7555b by Walter Bright: fix Issue 21038 - wchar and dchar string alignment should be 2 and 4, respectively https://github.com/dlang/dmd/pull/11528 --

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