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From: Simon Marchi <simon.marchi@polymtl.ca>
To: Fangrui Song <maskray@google.com>, Alan Modra <amodra@gmail.com>,
	Jan Beulich <jbeulich@suse.com>, Nick Clifton <nickc@redhat.com>
Cc: binutils@sourceware.org, gdb-patches@sourceware.org
Subject: Re: [PATCH v3] binutils, gdb: support zstd compressed debug sections
Date: Fri, 23 Sep 2022 10:32:43 -0400	[thread overview]
Message-ID: <7eadf897-9370-5a00-ae57-8e07251b8702@polymtl.ca> (raw)
In-Reply-To: <20220923040837.550160-1-maskray@google.com>



On 2022-09-23 00:08, Fangrui Song wrote:
> PR29397 PR29563: The new configure option --with-zstd defaults to auto.
> If pkgconfig/libzstd.pc is found, define HAVE_ZSTD and support zstd
> compressed debug sections for most tools.
> 
> * bfd: for addr2line, objdump --dwarf, gdb, etc
> * gas: support --compress-debug-sections=zstd
> * ld: support ELFCOMPRESS_ZSTD input and --compress-debug-sections=zstd
> * objcopy: support ELFCOMPRESS_ZSTD input for
>   --decompress-debug-sections and --compress-debug-sections=zstd
> * gdb: support ELFCOMPRESS_ZSTD input.  The bfd change references zstd
>   symbols, so gdb has to link against -lzstd in this patch.
> 
> If zstd is not supported, ELFCOMPRESS_ZSTD input triggers an error.  We
> can avoid HAVE_ZSTD if binutils-gdb imports zstd/ like zlib/, but this
> is too heavyweight, so don't do it for now.
> 
> ```
> % ld/ld-new a.o
> ld/ld-new: a.o: section .debug_abbrev is compressed with zstd, but BFD is not built with zstd support
> ...
> 
> % ld/ld-new a.o --compress-debug-sections=zstd
> ld/ld-new: --compress-debug-sections=zstd: ld is not built with zstd support
> 
> % binutils/objcopy --compress-debug-sections=zstd a.o b.o
> binutils/objcopy: --compress-debug-sections=zstd: binutils is not built with zstd support
> 
> % binutils/objcopy b.o --decompress-debug-sections
> binutils/objcopy: zstd.o: section .debug_abbrev is compressed with zstd, but BFD is not built with zstd support
> ...
> ```
> ---
> Changes from v1:
> * use PKG_CHECK_MODULES to check libzstd.pc
> 
> Changes from v2:
> * Improve PKG_CHECK_MODULES, autoreconf -vf
> * objcopy: check --compress-debug-sections=zstd in a !HAVE_ZSTD build

Just one question: you moved PKG_PROG_PKG_CONFIG up in ld/configure.ac,
which I think is ok.  But what about the other configure.ac files, don't
they need PKG_PROG_PKG_CONFIG too?  gdb/configure.ac, for instance, uses
pkg-config for debuginfod.  So if the user passes --without-debuginfod
--with-zstd, I expect things to fail, as the pkg-config will be skipped.
binutils/configure.ac probably has the same problem, since it uses
PKG_CHECK_MODULES for msgpack.

I would suggest using PKG_PROG_PKG_CONFIG at the top of all configure.ac
that use AM_ZSTD, out of precaution.

Simon

  reply	other threads:[~2022-09-23 14:32 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-23  4:08 Fangrui Song
2022-09-23 14:32 ` Simon Marchi [this message]
2022-09-26  5:12   ` Alan Modra
2022-09-26  7:20     ` Fangrui Song
2022-09-26 13:30       ` Alan Modra
2022-09-26 14:08     ` Simon Marchi
2022-09-27  0:33       ` Alan Modra
2022-09-23 15:45 ` Nick Clifton
2022-09-23 15:58   ` Simon Marchi
2022-09-23 18:20     ` Fangrui Song
2022-09-23 18:57       ` Simon Marchi
2022-09-23 20:34         ` Fangrui Song
2022-09-24  5:43           ` Eli Zaretskii
2022-09-24  6:53 ` Enze Li
2022-09-24  7:13   ` Fangrui Song
2022-09-27 18:06     ` Tom Tromey
2022-09-27 18:08 ` Tom Tromey
2022-09-27 18:53   ` Fangrui Song
2022-09-29 11:43 ` Martin Liška
2022-09-29 20:17   ` Fangrui Song
2022-09-30  9:48     ` [PATCH][RFC] add --enable-zstd-compressed-debug-sections configure option Martin Liška
2022-09-30 11:25       ` Pedro Alves
2022-09-30 12:42         ` Martin Liška
2022-10-01  7:31           ` Fangrui Song
2022-10-03  7:49             ` Martin Liška
2022-10-03  7:50               ` [PATCH 1/2] refactor usage of compressed_debug_section_type Martin Liška
2022-10-11  7:14                 ` Martin Liška
2022-10-11 12:06                   ` Nick Clifton
2022-10-11 13:27                     ` Martin Liška
2022-10-03  7:50               ` [PATCH 2/2] add --enable-default-compressed-debug-sections-algorithm configure option Martin Liška
2022-10-11  7:14                 ` Martin Liška
2022-10-11 12:08                   ` Nick Clifton

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