[PATCH v3] binutils, gdb: support zstd compressed debug sections

[Fangrui Song]

On 2022-09-23, Simon Marchi wrote:
>
>
>On 2022-09-23 14:20, Fangrui Song wrote:
>> On 2022-09-23, Simon Marchi wrote:
>>>
>>>
>>> On 2022-09-23 11:45, Nick Clifton wrote:
>>>> Hi Fangrui,
>>>>
>>>>> 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.
>>
>> Hi Simon and Nick,
>>
>> I have checked that `make all-gdb` works in a --enable-gdb --without-debuginfod build.
>>
>> I then inspected the 2020 commits adding AC_DEBUGINFOD to
>> gdb/configure.ac and binutils/configure.ac. They come with no
>> PKG_PROG_PKG_CONFIG and config/debuginfod.m4 does not have
>> PKG_PROG_PKG_CONFIG, but they still work.  So I think AC_ZSTD doesn't
>> need PKG_PROG_PKG_CONFIG, either. Though I have no insight why it
>> behaves that way:)
>
>Ok, I am a bit confused.  Based on my comprehension, since the first
>call to PKG_CHECK_MODULES may not happen do to a condition:
>
>  if test "x$with_debuginfod" != xno; then
>    PKG_CHECK_MODULES([DEBUGINFOD], [libdebuginfod >= 0.179],
>    ...
>  fi
>
>... the probing for pkg-config should not happen if --without-debuginfod
>is used.  But in gdb/configure, I see that the probing for pkg-config
>actually appears outside the condition.
>
>Anyway, good if it works.
>
>> +diff --git a/gdb/NEWS b/gdb/NEWS
>> +index 9619842bc03..1457c99ff04 100644
>> +--- a/gdb/NEWS
>> ++++ b/gdb/NEWS
>> +@@ -57,6 +57,8 @@
>> + + * The Windows native target now supports target async.
>> + ++* gdb now supports zstd compressed debug sections (ELFCOMPRESS_ZSTD) for ELF.
>> ++
>
>I'm not sure I understand the diff above, but I think it's missing an
>empty line between the previous bullet and the new bullet.  Otherwise,
>that is OK for GDB.
>
>Simon

Thanks!  The gdb news entry looks like (immediately before "* New commands")

--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -57,6 +57,8 @@
  
  * The Windows native target now supports target async.
  
+* gdb now supports zstd compressed debug sections (ELFCOMPRESS_ZSTD) for ELF.
+
  * New commands
  
  maintenance set ignore-prologue-end-flag on|off