Re: [PATCH] stdlib: reorganize stdlib Makefile routines by functionality

[abush wang <abushwangs@gmail.com>]

[-- Attachment #1: Type: text/plain, Size: 3793 bytes --]

Hi, Lu
it seems like there is some build issue:
```
/usr/bin/ld: /tmp/cc1NV6qZ.ltrans2.ltrans.o: warning: relocation against
`seen_eof_include_file' in read-only section `.text'
/usr/bin/ld: /tmp/cc1NV6qZ.ltrans1.ltrans.o: in function `lang_add_wild':
/builddir/build/BUILD/binutils-2.42.50/build-x86_64-redhat-linux/ld/../../ld/ldlang.c:8518:(.text+0xa108):
undefined reference to `in_text_section_ordering_file'
/usr/bin/ld:
/builddir/build/BUILD/binutils-2.42.50/build-x86_64-redhat-linux/ld/../../ld/ldlang.c:8552:(.text+0xa3aa):
undefined reference to `seen_eof_include_file'
/usr/bin/ld:
/builddir/build/BUILD/binutils-2.42.50/build-x86_64-redhat-linux/ld/../../ld/ldlang.c:8553:(.text+0xa3b8):
undefined reference to `in_text_section_ordering_file'
/usr/bin/ld:
/builddir/build/BUILD/binutils-2.42.50/build-x86_64-redhat-linux/ld/../../ld/ldlang.c:8551:(.text+0xa48f):
undefined reference to `in_text_section_ordering_file'
/usr/bin/ld: /tmp/cc1NV6qZ.ltrans2.ltrans.o: in function
`ldfile_open_command_file_1.lto_priv.0':
/builddir/build/BUILD/binutils-2.42.50/build-x86_64-redhat-linux/ld/../../ld/ldfile.c:939:(.text+0x9fc2):
undefined reference to `in_text_section_ordering_file'
/usr/bin/ld:
/builddir/build/BUILD/binutils-2.42.50/build-x86_64-redhat-linux/ld/../../ld/ldfile.c:965:(.text+0x9ff3):
undefined reference to `in_text_section_ordering_file'
/usr/bin/ld:
/builddir/build/BUILD/binutils-2.42.50/build-x86_64-redhat-linux/ld/../../ld/ldfile.c:998:(.text+0xa0e7):
undefined reference to `in_text_section_ordering_file'
/usr/bin/ld:
/builddir/build/BUILD/binutils-2.42.50/build-x86_64-redhat-linux/ld/../../ld/ldfile.c:995:(.text+0xa0f7):
undefined reference to `seen_eof_include_file'
/usr/bin/ld: warning: creating DT_TEXTREL in a PIE
collect2: error: ld returned 1 exit status
make[4]: *** [Makefile:1265: ld-new] Error 1
make[3]: *** [Makefile:1903: all-recursive] Error 1
make[2]: *** [Makefile:1092: all] Error 2
make[1]: *** [Makefile:8046: all-ld] Error 2
```

test by binutils-2.42.50-6.fc41.src.rpm
this is my repo
https://mirrors.aliyun.com/fedora/development/rawhide/Everything/x86_64/os/
I have verified that the error reported is caused by these patches.


On Mon, Apr 1, 2024 at 9:17 PM H.J. Lu <hjl.tools@gmail.com> wrote:

> On Mon, Apr 1, 2024 at 6:13 AM Florian Weimer <fweimer@redhat.com> wrote:
> >
> > * abush wang:
> >
> > > This is test:
> > > ```
> > > uint64_t getnsecs() {
> > >     uint32_t lo, hi;
> > >     __asm__ __volatile__ (
> > >         "rdtsc" : "=a"(lo), "=d"(hi)
> > >     );
> > >     return ((uint64_t)hi << 32) | lo;
> > > }
> > >
> > > int main() {
> > >     const int num_iterations = 1;
> > >     uint64_t start, end, total_time = 0;
> > >
> > >     start = getnsecs();
> > >     for (int i = 0; i < num_iterations; i++) {
> > >         (void) lrand48();
> > >     }
> > >     end = getnsecs();
> > >     total_time += (end - start);
> > >
> > >     printf("Average time for lrand48: %lu cycles\n", total_time /
> num_iterations);
> > >     return 0;
> > > }
> > > ```
> > > before:
> > > Average time for lrand48: 21418 cycles
> > >
> > > after:
> > > Average time for lrand48: 9892 cycles
> >
> > Do you see this on x86-64?  So this isn't a displacement range issue?
> >
> > It could be that this is a random performance change due to code
> > alignment, and not actually caused by the direct call distance.
> >
>
> I have a linker patch to control section layout:
>
> https://patchwork.sourceware.org/project/binutils/list/?series=29973
>
> It can
>
> 1. Reduce gaps between text sections.
> 2. Put hot text sections close to each other.
>
> If it can solve this issue, we should add this feature to ld.
>
> --
> H.J.
>