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Diffstat (limited to 'gdb/doc/gdb.texinfo')
| -rw-r--r-- | gdb/doc/gdb.texinfo | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo index 80148f7..afe3845 100644 --- a/gdb/doc/gdb.texinfo +++ b/gdb/doc/gdb.texinfo @@ -15865,6 +15865,7 @@ program. To debug a core dump of a previous run, you must also tell @menu * Files:: Commands to specify files * Separate Debug Files:: Debugging information in separate files +* MiniDebugInfo:: Debugging information in a special section * Index Files:: Index files speed up GDB * Symbol Errors:: Errors reading symbol files * Data Files:: GDB data files @@ -16790,6 +16791,55 @@ gnu_debuglink_crc32 (unsigned long crc, @noindent This computation does not apply to the ``build ID'' method. +@node MiniDebugInfo +@section Debugging information in a special section +@cindex separate debug sections +@cindex @samp{.gnu_debugdata} section + +Some systems ship pre-built executables and libraries that have a +special @samp{.gnu_debugdata} section. This feature is called +@dfn{MiniDebugInfo}. This section holds an LZMA-compressed object and +is used to supply extra symbols for backtraces. + +The intent of this section is to provide extra minimal debugging +information for use in simple backtraces. It is not intended to be a +replacement for full separate debugging information (@pxref{Separate +Debug Files}). The example below shows the intended use; however, +@value{GDBN} does not currently put restrictions on what sort of +debugging information might be included in the section. + +@value{GDBN} has support for this extension. If the section exists, +then it is used provided that no other source of debugging information +can be found, and that @value{GDBN} was configured with LZMA support. + +This section can be easily created using @command{objcopy} and other +standard utilities: + +@smallexample +# Extract the dynamic symbols from the main binary, there is no need +# to also have these in the normal symbol table +nm -D @var{binary} --format=posix --defined-only \ + | awk '@{ print $1 @}' | sort > dynsyms + +# Extract all the text (i.e. function) symbols from the debuginfo . +nm @var{binary} --format=posix --defined-only \ + | awk '@{ if ($2 == "T" || $2 == "t") print $1 @}' \ + | sort > funcsyms + +# Keep all the function symbols not already in the dynamic symbol +# table. +comm -13 dynsyms funcsyms > keep_symbols + +# Copy the full debuginfo, keeping only a minimal set of symbols and +# removing some unnecessary sections. +objcopy -S --remove-section .gdb_index --remove-section .comment \ + --keep-symbols=keep_symbols @var{binary} mini_debuginfo + +# Inject the compressed data into the .gnu_debugdata section of the +# original binary. +xz mini_debuginfo +objcopy --add-section .gnu_debugdata=mini_debuginfo.xz @var{binary} +@end smallexample @node Index Files @section Index Files Speed Up @value{GDBN} |