PR gdb/14704:

* gdb_bfd.c (gdb_bfd_ref): Set BFD_DECOMPRESS.
	(zlib_decompress_section): Remove.
	(gdb_bfd_map_section): Only check for compressed section
	in mmap case.  Use bfd_get_full_section_contents.
	* osabi.c (check_note): Add 'sectsize' argument.  Read
	section data.
	(generic_elf_osabi_sniff_abi_tag_sections): Don't read
	section data.  Update for check_note change.
	* xcoffread.c (xcoff_initial_scan): Use
	bfd_get_full_section_contents.
	* py-auto-load.c (auto_load_section_scripts): Use
	bfd_get_full_section_contents.
	* contrib/cc-with-tweaks.sh: Add -Z option.
testsuite
	* gdb.base/comprdebug.exp: New file.

gdb/ChangeLog

@@ -1,3 +1,20 @@
+2012-11-08  Tom Tromey  <tromey@redhat.com>
+
+	PR gdb/14704:
+	* gdb_bfd.c (gdb_bfd_ref): Set BFD_DECOMPRESS.
+	(zlib_decompress_section): Remove.
+	(gdb_bfd_map_section): Only check for compressed section
+	in mmap case.  Use bfd_get_full_section_contents.
+	* osabi.c (check_note): Add 'sectsize' argument.  Read
+	section data.
+	(generic_elf_osabi_sniff_abi_tag_sections): Don't read
+	section data.  Update for check_note change.
+	* xcoffread.c (xcoff_initial_scan): Use
+	bfd_get_full_section_contents.
+	* py-auto-load.c (auto_load_section_scripts): Use
+	bfd_get_full_section_contents.
+	* contrib/cc-with-tweaks.sh: Add -Z option.
+
 2012-11-08  Tom Tromey  <tromey@redhat.com>
 
 	* python/py-bpevent.c: Include defs.h.

gdb/contrib/cc-with-tweaks.sh

@@ -36,6 +36,7 @@
 # (More documentation is to come.)
 
 # ARGS determine what is done.  They can be:
+# -Z invoke objcopy --compress-debug-sections
 # -z compress using dwz
 # -m compress using dwz -m
 # -i make an index
@@ -74,9 +75,11 @@ want_index=false
 want_dwz=false
 want_multi=false
 want_dwp=false
+want_objcopy_compress=false
 
 while [ $# -gt 0 ]; do
     case "$1" in
+	-Z) want_objcopy_compress=true ;;
 	-z) want_dwz=true ;;
 	-i) want_index=true ;;
 	-m) want_multi=true ;;
@@ -138,6 +141,12 @@ then
     exit 1
 fi
 
+if [ "$want_objcopy_compress" = true ]; then
+    $OBJCOPY --compress-debug-sections "$output_file"
+    rc=$?
+    [ $rc != 0 ] && exit $rc
+fi
+
 if [ "$want_index" = true ]; then
     $GDB --batch-silent -nx -ex "set auto-load no" -ex "file $output_file" -ex "save gdb-index $output_dir"
     rc=$?

gdb/gdb_bfd.c

@@ -258,6 +258,9 @@ gdb_bfd_ref (struct bfd *abfd)
       return;
     }
 
+  /* Ask BFD to decompress sections in bfd_get_full_section_contents.  */
+  abfd->flags |= BFD_DECOMPRESS;
+
   gdata = bfd_zalloc (abfd, sizeof (struct gdb_bfd_data));
   gdata->refc = 1;
   gdata->mtime = bfd_get_mtime (abfd);
@@ -337,98 +340,6 @@ get_section_descriptor (asection *section)
   return result;
 }
 
-/* Decompress a section that was compressed using zlib.  Store the
-   decompressed buffer, and its size, in DESCRIPTOR.  */
-
-static void
-zlib_decompress_section (asection *sectp,
-			 struct gdb_bfd_section_data *descriptor)
-{
-  bfd *abfd = sectp->owner;
-#ifndef HAVE_ZLIB_H
-  error (_("Support for zlib-compressed data (from '%s', section '%s') "
-           "is disabled in this copy of GDB"),
-         bfd_get_filename (abfd),
-	 bfd_get_section_name (abfd, sectp));
-#else
-  bfd_size_type compressed_size = bfd_get_section_size (sectp);
-  gdb_byte *compressed_buffer = xmalloc (compressed_size);
-  struct cleanup *cleanup = make_cleanup (xfree, compressed_buffer);
-  struct cleanup *inner_cleanup;
-  bfd_size_type uncompressed_size;
-  gdb_byte *uncompressed_buffer;
-  z_stream strm;
-  int rc;
-  int header_size = 12;
-
-  if (bfd_seek (abfd, sectp->filepos, SEEK_SET) != 0
-      || bfd_bread (compressed_buffer,
-		    compressed_size, abfd) != compressed_size)
-    error (_("can't read data from '%s', section '%s'"),
-           bfd_get_filename (abfd),
-	   bfd_get_section_name (abfd, sectp));
-
-  /* Read the zlib header.  In this case, it should be "ZLIB" followed
-     by the uncompressed section size, 8 bytes in big-endian order.  */
-  if (compressed_size < header_size
-      || strncmp (compressed_buffer, "ZLIB", 4) != 0)
-    error (_("corrupt ZLIB header from '%s', section '%s'"),
-           bfd_get_filename (abfd),
-	   bfd_get_section_name (abfd, sectp));
-  uncompressed_size = compressed_buffer[4]; uncompressed_size <<= 8;
-  uncompressed_size += compressed_buffer[5]; uncompressed_size <<= 8;
-  uncompressed_size += compressed_buffer[6]; uncompressed_size <<= 8;
-  uncompressed_size += compressed_buffer[7]; uncompressed_size <<= 8;
-  uncompressed_size += compressed_buffer[8]; uncompressed_size <<= 8;
-  uncompressed_size += compressed_buffer[9]; uncompressed_size <<= 8;
-  uncompressed_size += compressed_buffer[10]; uncompressed_size <<= 8;
-  uncompressed_size += compressed_buffer[11];
-
-  /* It is possible the section consists of several compressed
-     buffers concatenated together, so we uncompress in a loop.  */
-  strm.zalloc = NULL;
-  strm.zfree = NULL;
-  strm.opaque = NULL;
-  strm.avail_in = compressed_size - header_size;
-  strm.next_in = (Bytef*) compressed_buffer + header_size;
-  strm.avail_out = uncompressed_size;
-  uncompressed_buffer = xmalloc (uncompressed_size);
-  inner_cleanup = make_cleanup (xfree, uncompressed_buffer);
-  rc = inflateInit (&strm);
-  while (strm.avail_in > 0)
-    {
-      if (rc != Z_OK)
-        error (_("setting up uncompression in '%s', section '%s': %d"),
-               bfd_get_filename (abfd),
-	       bfd_get_section_name (abfd, sectp),
-	       rc);
-      strm.next_out = ((Bytef*) uncompressed_buffer
-                       + (uncompressed_size - strm.avail_out));
-      rc = inflate (&strm, Z_FINISH);
-      if (rc != Z_STREAM_END)
-        error (_("zlib error uncompressing from '%s', section '%s': %d"),
-               bfd_get_filename (abfd),
-	       bfd_get_section_name (abfd, sectp),
-	       rc);
-      rc = inflateReset (&strm);
-    }
-  rc = inflateEnd (&strm);
-  if (rc != Z_OK
-      || strm.avail_out != 0)
-    error (_("concluding uncompression in '%s', section '%s': %d"),
-           bfd_get_filename (abfd),
-	   bfd_get_section_name (abfd, sectp),
-	   rc);
-
-  discard_cleanups (inner_cleanup);
-  do_cleanups (cleanup);
-
-  /* Attach the data to the BFD section.  */
-  descriptor->data = uncompressed_buffer;
-  descriptor->size = uncompressed_size;
-#endif
-}
-
 /* See gdb_bfd.h.  */
 
 const gdb_byte *
@@ -437,6 +348,7 @@ gdb_bfd_map_section (asection *sectp, bfd_size_type *size)
   bfd *abfd;
   unsigned char header[4];
   struct gdb_bfd_section_data *descriptor;
+  bfd_byte *data;
 
   gdb_assert ((sectp->flags & SEC_RELOC) == 0);
   gdb_assert (size != NULL);
@@ -449,20 +361,8 @@ gdb_bfd_map_section (asection *sectp, bfd_size_type *size)
   if (descriptor->data != NULL)
     goto done;
 
-  /* Check if the file has a 4-byte header indicating compression.  */
-  if (bfd_get_section_size (sectp) > sizeof (header)
-      && bfd_seek (abfd, sectp->filepos, SEEK_SET) == 0
-      && bfd_bread (header, sizeof (header), abfd) == sizeof (header))
-    {
-      /* Upon decompression, update the buffer and its size.  */
-      if (strncmp (header, "ZLIB", sizeof (header)) == 0)
-        {
-          zlib_decompress_section (sectp, descriptor);
-	  goto done;
-        }
-    }
-
 #ifdef HAVE_MMAP
+  if (!bfd_is_section_compressed (abfd, sectp))
     {
       /* The page size, used when mmapping.  */
       static int pagesize;
@@ -496,20 +396,18 @@ gdb_bfd_map_section (asection *sectp, bfd_size_type *size)
     }
 #endif /* HAVE_MMAP */
 
-  /* If we get here, we are a normal, not-compressed section.  */
+  /* Handle compressed sections, or ordinary uncompressed sections in
+     the no-mmap case.  */
 
   descriptor->size = bfd_get_section_size (sectp);
-  descriptor->data = xmalloc (descriptor->size);
-
-  if (bfd_seek (abfd, sectp->filepos, SEEK_SET) != 0
-      || bfd_bread (descriptor->data, bfd_get_section_size (sectp),
-		    abfd) != bfd_get_section_size (sectp))
-    {
-      xfree (descriptor->data);
   descriptor->data = NULL;
-      error (_("Can't read data for section '%s'"),
+
+  data = NULL;
+  if (!bfd_get_full_section_contents (abfd, sectp, &data))
+    error (_("Can't read data for section '%s' in file '%s'"),
+	   bfd_get_section_name (abfd, sectp),
 	   bfd_get_filename (abfd));
-    }
+  descriptor->data = data;
 
  done:
   gdb_assert (descriptor->data != NULL);

gdb/osabi.c

@@ -370,14 +370,23 @@ gdbarch_init_osabi (struct gdbarch_info info, struct gdbarch *gdbarch)
 /* Limit on the amount of data to be read.  */
 #define MAX_NOTESZ	128
 
-/* Return non-zero if NOTE matches NAME, DESCSZ and TYPE.  */
+/* Return non-zero if NOTE matches NAME, DESCSZ and TYPE.  If
+   *SECTSIZE is non-zero, then this reads that many bytes from
+   the start of the section and clears *SECTSIZE.  */
 
 static int
-check_note (bfd *abfd, asection *sect, const char *note,
+check_note (bfd *abfd, asection *sect, char *note, unsigned int *sectsize,
 	    const char *name, unsigned long descsz, unsigned long type)
 {
   unsigned long notesz;
 
+  if (*sectsize)
+    {
+      if (!bfd_get_section_contents (abfd, sect, note, 0, *sectsize))
+	return 0;
+      *sectsize = 0;
+    }
+
   /* Calculate the size of this note.  */
   notesz = strlen (name) + 1;
   notesz = ((notesz + 3) & ~3);
@@ -424,14 +433,18 @@ generic_elf_osabi_sniff_abi_tag_sections (bfd *abfd, asection *sect, void *obj)
   if (sectsize > MAX_NOTESZ)
     sectsize = MAX_NOTESZ;
 
+  /* We lazily read the section data here.  Since we use
+     BFD_DECOMPRESS, we can't use bfd_get_section_contents on a
+     compressed section.  But, since note sections are not compressed,
+     deferring the reading until we recognize the section avoids any
+     error.  */
   note = alloca (sectsize);
-  bfd_get_section_contents (abfd, sect, note, 0, sectsize);
 
   /* .note.ABI-tag notes, used by GNU/Linux and FreeBSD.  */
   if (strcmp (name, ".note.ABI-tag") == 0)
     {
       /* GNU.  */
-      if (check_note (abfd, sect, note, "GNU", 16, NT_GNU_ABI_TAG))
+      if (check_note (abfd, sect, note, &sectsize, "GNU", 16, NT_GNU_ABI_TAG))
 	{
 	  unsigned int abi_tag = bfd_h_get_32 (abfd, note + 16);
 
@@ -467,7 +480,8 @@ generic_elf_osabi_sniff_abi_tag_sections (bfd *abfd, asection *sect, void *obj)
 	}
 
       /* FreeBSD.  */
-      if (check_note (abfd, sect, note, "FreeBSD", 4, NT_FREEBSD_ABI_TAG))
+      if (check_note (abfd, sect, note, &sectsize, "FreeBSD", 4,
+		      NT_FREEBSD_ABI_TAG))
 	{
 	  /* There is no need to check the version yet.  */
 	  *osabi = GDB_OSABI_FREEBSD_ELF;
@@ -479,7 +493,7 @@ generic_elf_osabi_sniff_abi_tag_sections (bfd *abfd, asection *sect, void *obj)
       
   /* .note.netbsd.ident notes, used by NetBSD.  */
   if (strcmp (name, ".note.netbsd.ident") == 0
-      && check_note (abfd, sect, note, "NetBSD", 4, NT_NETBSD_IDENT))
+      && check_note (abfd, sect, note, &sectsize, "NetBSD", 4, NT_NETBSD_IDENT))
     {
       /* There is no need to check the version yet.  */
       *osabi = GDB_OSABI_NETBSD_ELF;
@@ -488,7 +502,8 @@ generic_elf_osabi_sniff_abi_tag_sections (bfd *abfd, asection *sect, void *obj)
 
   /* .note.openbsd.ident notes, used by OpenBSD.  */
   if (strcmp (name, ".note.openbsd.ident") == 0
-      && check_note (abfd, sect, note, "OpenBSD", 4, NT_OPENBSD_IDENT))
+      && check_note (abfd, sect, note, &sectsize, "OpenBSD", 4,
+		     NT_OPENBSD_IDENT))
     {
       /* There is no need to check the version yet.  */
       *osabi = GDB_OSABI_OPENBSD_ELF;

gdb/python/py-auto-load.c

@@ -197,27 +197,26 @@ auto_load_section_scripts (struct objfile *objfile, const char *section_name)
 {
   bfd *abfd = objfile->obfd;
   asection *scripts_sect;
-  bfd_size_type size;
+  bfd_byte *data = NULL;
-  char *p;
-  struct cleanup *cleanups;
 
   scripts_sect = bfd_get_section_by_name (abfd, section_name);
   if (scripts_sect == NULL)
     return;
 
-  size = bfd_get_section_size (scripts_sect);
+  if (!bfd_get_full_section_contents (abfd, scripts_sect, &data))
-  p = xmalloc (size);
-  
-  cleanups = make_cleanup (xfree, p);
-
-  if (bfd_get_section_contents (abfd, scripts_sect, p, (file_ptr) 0, size))
-    source_section_scripts (objfile, section_name, p, p + size);
-  else
     warning (_("Couldn't read %s section of %s"),
 	     section_name, bfd_get_filename (abfd));
+  else
+    {
+      struct cleanup *cleanups;
+      char *p = (char *) data;
 
+      cleanups = make_cleanup (xfree, p);
+      source_section_scripts (objfile, section_name, p,
+			      p + bfd_get_section_size (scripts_sect));
       do_cleanups (cleanups);
     }
+}
 
 /* Load any Python auto-loaded scripts for OBJFILE.  */
 

gdb/testsuite/ChangeLog

@@ -1,3 +1,7 @@
+2012-11-08  Tom Tromey  <tromey@redhat.com>
+
+	* gdb.base/comprdebug.exp: New file.
+
 2012-11-06  Pedro Alves  <palves@redhat.com>
 
 	PR gdb/14810

gdb/testsuite/gdb.base/comprdebug.exp

@@ -0,0 +1,46 @@
+# Copyright 2012 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+standard_testfile average.c
+
+set ofile "${binfile}0.o"
+if {[gdb_compile $srcdir/$subdir/$srcfile $ofile \
+	 object {debug}] != ""} {
+    untested comprdebug.exp
+    return
+}
+
+set objcopy_program [transform objcopy]
+set cmd "$objcopy_program --compress-debug-sections $ofile"
+verbose "invoking $cmd"
+set result [catch "exec $cmd" output]
+verbose "result is $result"
+verbose "output is $output"
+
+if {$result == 1} {
+    untested comprdebug.exp
+    return
+}
+
+gdb_exit
+gdb_start
+gdb_reinitialize_dir $srcdir/$subdir
+set testname "file [file tail $ofile]"
+if {[gdb_file_cmd $ofile] == 0} {
+    pass $testname
+} else {
+    fail $testname
+}
+

gdb/xcoffread.c

@@ -2989,7 +2989,7 @@ xcoff_initial_scan (struct objfile *objfile, int symfile_flags)
       {
 	struct bfd_section *secp;
 	bfd_size_type length;
-	char *debugsec = NULL;
+	bfd_byte *debugsec = NULL;
 
 	secp = bfd_get_section_by_name (abfd, ".debug");
 	if (secp)
@@ -2997,11 +2997,9 @@ xcoff_initial_scan (struct objfile *objfile, int symfile_flags)
 	    length = bfd_section_size (abfd, secp);
 	    if (length)
 	      {
-		debugsec =
+		debugsec = obstack_alloc (&objfile->objfile_obstack, length);
-		  (char *) obstack_alloc (&objfile->objfile_obstack, length);
 
-		if (!bfd_get_section_contents (abfd, secp, debugsec,
+		if (!bfd_get_full_section_contents (abfd, secp, &debugsec))
-					       (file_ptr) 0, length))
 		  {
 		    error (_("Error reading .debug section of `%s': %s"),
 			   name, bfd_errmsg (bfd_get_error ()));