add --enable-default-compressed-debug-sections-algorithm configure option

ChangeLog:

	* configure.ac: Add --enable-default-compressed-debug-sections-algorithm.
	* configure: Regenerate.

gas/ChangeLog:

	* NEWS: Document the new option.
	* as.c (flag_compress_debug): Set default algorithm based
	on the configure option.
	* configure.ac: Add --enable-default-compressed-debug-sections-algorithm.
	* configure: Regenerate.
	* config.in: Likewise.

ld/ChangeLog:

	* NEWS: Document the new option.
	* configure.ac: Add --enable-default-compressed-debug-sections-algorithm.
	* configure: Regenerate.
	* config.in: Likewise.
	* ldmain.c: Set default algorithm based
	on the configure option.

5 files changed, 40 insertions, 3 deletions

diff --git a/gas/NEWS b/gas/NEWS
index cc0c62d7f18..16cb347e775 100644
--- a/gas/NEWS
+++ b/gas/NEWS
@@ -2,6 +2,9 @@
 
 * gas now supports --compress-debug-sections=zstd to compress
   debug sections with zstd.
+* Add --enable-default-compressed-debug-sections-algorithm={zlib,zstd}
+  that selects the default compression algorithm
+  for --enable-compressed-debug-sections.
 
 * Add support for various T-Head extensions (XTheadBa, XTheadBb, XTheadBs,
   XTheadCmo, XTheadCondMov, XTheadFMemIdx, XTheadMemIdx, XTheadMemPair,
diff --git a/gas/as.c b/gas/as.c
index a5c2d2459f7..d42dd5394b5 100644
--- a/gas/as.c
+++ b/gas/as.c
@@ -226,7 +226,7 @@ print_version_id (void)
 
 #ifdef DEFAULT_FLAG_COMPRESS_DEBUG
 enum compressed_debug_section_type flag_compress_debug
-  = COMPRESS_DEBUG_GABI_ZLIB;
+  = DEFAULT_COMPRESSED_DEBUG_ALGORITHM;
 #endif
 
 static void
diff --git a/gas/config.in b/gas/config.in
index 0d1668a3eac..232bc350759 100644
--- a/gas/config.in
+++ b/gas/config.in
@@ -22,6 +22,9 @@
 /* Default architecture. */
 #undef DEFAULT_ARCH
 
+/* Default compression algorithm for --enable-compressed-debug-sections. */
+#undef DEFAULT_COMPRESSED_DEBUG_ALGORITHM
+
 /* Default CRIS architecture. */
 #undef DEFAULT_CRIS_ARCH
 
diff --git a/gas/configure b/gas/configure
index 02cded59b6a..cae14c066d2 100755
--- a/gas/configure
+++ b/gas/configure
@@ -810,6 +810,7 @@ enable_largefile
 enable_targets
 enable_checking
 enable_compressed_debug_sections
+enable_default_compressed_debug_sections_algorithm
 enable_x86_relax_relocations
 enable_elf_stt_common
 enable_generate_build_notes
@@ -1476,6 +1477,9 @@ Optional Features:
   --enable-checking       enable run-time checks
   --enable-compressed-debug-sections={all,gas,none}
                           compress debug sections by default
+  --enable-default-compressed-debug-sections-algorithm={zlib,zstd}
+                          Default compression algorithm for
+                          --enable-compressed-debug-sections.
   --enable-x86-relax-relocations
                           generate x86 relax relocations by default
   --enable-elf-stt-common generate ELF common symbols with STT_COMMON type by
@@ -10722,7 +10726,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 10725 "configure"
+#line 10729 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -10828,7 +10832,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 10831 "configure"
+#line 10835 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -11502,6 +11506,15 @@ if test "${enable_compressed_debug_sections+set}" = set; then :
 esac
 fi
 
+# Select default compression algorithm.
+ac_default_compressed_debug_sections_algorithm=COMPRESS_DEBUG_GABI_ZLIB
+# Check whether --enable-default_compressed_debug_sections_algorithm was given.
+if test "${enable_default_compressed_debug_sections_algorithm+set}" = set; then :
+  enableval=$enable_default_compressed_debug_sections_algorithm; case "${enableval}" in
+   zstd) ac_default_compressed_debug_sections_algorithm=COMPRESS_DEBUG_ZSTD ;;
+esac
+fi
+
 # PR gas/19520
 # Decide if x86 assembler should generate relax relocations.
 ac_default_x86_relax_relocations=unset
@@ -12671,6 +12684,12 @@ $as_echo "#define DEFAULT_FLAG_COMPRESS_DEBUG 1" >>confdefs.h
 
 fi
 
+
+cat >>confdefs.h <<_ACEOF
+#define DEFAULT_COMPRESSED_DEBUG_ALGORITHM $ac_default_compressed_debug_sections_algorithm
+_ACEOF
+
+
 # Turn on all targets if possible
 if test ${all_targets} = "yes"; then
   case ${target_cpu_type} in
diff --git a/gas/configure.ac b/gas/configure.ac
index e6f3298cb3e..feb43399ce8 100644
--- a/gas/configure.ac
+++ b/gas/configure.ac
@@ -76,6 +76,15 @@ AC_ARG_ENABLE(compressed_debug_sections,
   *)   ac_default_compressed_debug_sections=unset ;;
 esac])dnl
 
+# Select default compression algorithm.
+ac_default_compressed_debug_sections_algorithm=COMPRESS_DEBUG_GABI_ZLIB
+AC_ARG_ENABLE(default_compressed_debug_sections_algorithm,
+	      AS_HELP_STRING([--enable-default-compressed-debug-sections-algorithm={zlib,zstd}],
+	      [Default compression algorithm for --enable-compressed-debug-sections.]),
+[case "${enableval}" in
+   zstd) ac_default_compressed_debug_sections_algorithm=COMPRESS_DEBUG_ZSTD ;;
+esac])dnl
+
 # PR gas/19520
 # Decide if x86 assembler should generate relax relocations.
 ac_default_x86_relax_relocations=unset
@@ -755,6 +764,9 @@ if test x$ac_default_compressed_debug_sections = xyes ; then
   AC_DEFINE(DEFAULT_FLAG_COMPRESS_DEBUG, 1, [Define if you want compressed debug sections by default.])
 fi
 
+AC_DEFINE_UNQUOTED(DEFAULT_COMPRESSED_DEBUG_ALGORITHM, $ac_default_compressed_debug_sections_algorithm,
+		   [Default compression algorithm for --enable-compressed-debug-sections.])
+
 # Turn on all targets if possible
 if test ${all_targets} = "yes"; then
   case ${target_cpu_type} in