Commit: Expand linker documentation of --compress-debug-sections option

[Nick Clifton <nickc at redhat dot com>]

Hi Guys,

  I am checking in the patch below to expand the documentation of the
  linker's --compress-debug-section option.  I got to wondering if the
  linker would pass compressed debug sections in input files straight
  through to the output file even if the --compress-debug-sections=none
  option was in effect.  It turns out that it does not, but that this
  fact was not described in the documentation.  Hence the update.

Cheers
  Nick

ld/ChangeLog
2016-11-07  Nick Clifton  <nickc@redhat.com>

	* ld.texinfo (--compress-debug-sections): Expand documentation of
	this option.

diff --git a/ld/ld.texinfo b/ld/ld.texinfo
index 500fda6..698d366 100644
--- a/ld/ld.texinfo
+++ b/ld/ld.texinfo
@@ -2319,17 +2319,28 @@ hash tables.  The default is @code{sysv}.
 @itemx --compress-debug-sections=zlib
 @itemx --compress-debug-sections=zlib-gnu
 @itemx --compress-debug-sections=zlib-gabi
-On ELF platforms , these options control how DWARF debug sections are
-compressed using zlib.  @option{--compress-debug-sections=none} doesn't
-compress DWARF debug sections.
-@option{--compress-debug-sections=zlib-gnu} compresses DWARF debug
-sections and rename debug section names to begin with @samp{.zdebug}
-instead of @samp{.debug}.  @option{--compress-debug-sections=zlib}
-and @option{--compress-debug-sections=zlib-gabi}
-compress DWARF debug sections with SHF_COMPRESSED from the ELF ABI.
-The default behaviour varies depending upon the target involved and
-the configure options used to build the toolchain.  The default can be
-determined by examing the output from the linker's @option{--help} option.
+On ELF platforms, these options control how DWARF debug sections are
+compressed using zlib.
+
+@option{--compress-debug-sections=none} doesn't compress DWARF debug
+sections.  @option{--compress-debug-sections=zlib-gnu} compresses
+DWARF debug sections and renames them to begin with @samp{.zdebug}
+instead of @samp{.debug}.  @option{--compress-debug-sections=zlib-gabi}
+also compresses DWARF debug sections, but rather than renaming them it
+sets the SHF_COMPRESSED flag in the sections' headers.
+
+The @option{--compress-debug-sections=zlib} option is an alias for
+@option{--compress-debug-sections=zlib-gabi}.
+
+Note that this option overrides any compression in input debug
+sections, so if a binary is linked with @option{--compress-debug-sections=none}
+for example, then any compressed debug sections in input files will be
+uncompressed before they are copied into the output binary.
+
+The default compression behaviour varies depending upon the target
+involved and the configure options used to build the toolchain.  The
+default can be determined by examining the output from the linker's
+@option{--help} option.
 
 @kindex --reduce-memory-overheads
 @item --reduce-memory-overheads