[gcc r11-6412] Darwin : Adjust defaults for current bootstrap constraints.

[Iain D Sandoe]

https://gcc.gnu.org/g:b2cee5e1e89c8f939bc36fe9756befcb93d96982

commit r11-6412-gb2cee5e1e89c8f939bc36fe9756befcb93d96982
Author: Iain Sandoe <iain@sandoe.co.uk>
Date:   Wed Dec 30 10:36:52 2020 +0000

    Darwin : Adjust defaults for current bootstrap constraints.
    
    The toolchain now requires a C++11 compiler to bootstrap and
    none of the older Darwin toolchains which were based on stabs
    debugging are suitable.  We can simplify the debug setup now.
    
    gcc/ChangeLog:
    
            * config/darwin.h (DSYMUTIL_SPEC): Default to DWARF
            (ASM_DEBUG_SPEC):Only define if the assembler supports
            stabs.
            (PREFERRED_DEBUGGING_TYPE): Default to DWARF.
            (DARWIN_PREFER_DWARF): Define.
            * config/darwin9.h (PREFERRED_DEBUGGING_TYPE): Remove.
            (DARWIN_PREFER_DWARF): Likewise
            (DSYMUTIL_SPEC): Likewise.
            (COLLECT_RUN_DSYMUTIL): Likewise.
            (ASM_DEBUG_SPEC): Likewise.
            (ASM_DEBUG_OPTION_SPEC): Likewise.

Diff:
---
 gcc/config/darwin.h  | 37 ++++++++++++++++++++++++++-----------
 gcc/config/darwin9.h | 26 --------------------------
 2 files changed, 26 insertions(+), 37 deletions(-)

diff --git a/gcc/config/darwin.h b/gcc/config/darwin.h
index da40a08443e..93e7796e850 100644
--- a/gcc/config/darwin.h
+++ b/gcc/config/darwin.h
@@ -241,12 +241,18 @@ extern GTY(()) int darwin_ms_struct;
 
 #define DSYMUTIL "\ndsymutil"
 
+/* Spec that controls whether the debug linker is run automatically for
+   a link step.  This needs to be done if there is a source file on the
+   command line which will result in a temporary object (and debug is
+   enabled).  */
+
 #define DSYMUTIL_SPEC \
    "%{!fdump=*:%{!fsyntax-only:%{!c:%{!M:%{!MM:%{!E:%{!S:\
     %{v} \
-    %{gdwarf-2:%{!gstabs*:%{%:debug-level-gt(0): -idsym}}}\
-    %{.c|.cc|.C|.cpp|.cp|.c++|.cxx|.CPP|.m|.mm: \
-    %{gdwarf-2:%{!gstabs*:%{%:debug-level-gt(0): -dsym}}}}}}}}}}}"
+    %{g*:%{!gstabs*:%{%:debug-level-gt(0): -idsym}}}\
+    %{.c|.cc|.C|.cpp|.cp|.c++|.cxx|.CPP|.m|.mm|.s|.f|.f90|\
+      .f95|.f03|.f77|.for|.F|.F90|.F95|.F03: \
+    %{g*:%{!gstabs*:%{%:debug-level-gt(0): -dsym}}}}}}}}}}}"
 
 #define LINK_COMMAND_SPEC LINK_COMMAND_SPEC_A DSYMUTIL_SPEC
 
@@ -472,22 +478,31 @@ extern GTY(()) int darwin_ms_struct;
   %{Zforce_cpusubtype_ALL:-force_cpusubtype_ALL} \
   %{static}" ASM_MMACOSX_VERSION_MIN_SPEC
 
-/* Default ASM_DEBUG_SPEC.  Darwin's as cannot currently produce dwarf
-   debugging data.  */
-
+#ifdef HAVE_AS_STABS_DIRECTIVE
+/* We only pass a debug option to the assembler if that supports stabs, since
+   dwarf is not uniformly supported in the assemblers.  */
 #define ASM_DEBUG_SPEC  "%{g*:%{%:debug-level-gt(0):%{!gdwarf*:--gstabs}}}"
-#define ASM_DEBUG_OPTION_SPEC ""
+#else
+#define ASM_DEBUG_SPEC  ""
+#endif
+
+#undef  ASM_DEBUG_OPTION_SPEC
+#define ASM_DEBUG_OPTION_SPEC	""
+
 #define ASM_FINAL_SPEC \
   "%{gsplit-dwarf:%ngsplit-dwarf is not supported on this platform} %<gsplit-dwarf"
 
-/* We still allow output of STABS if the assembler supports it.  */
+/* We now require C++11 to bootstrap and newer tools than those based on
+   stabs, so require DWARF-2, even if stabs is supported by the assembler.  */
+
+#define PREFERRED_DEBUGGING_TYPE DWARF2_DEBUG
+#define DARWIN_PREFER_DWARF
+#define DWARF2_DEBUGGING_INFO 1
+
 #ifdef HAVE_AS_STABS_DIRECTIVE
 #define DBX_DEBUGGING_INFO 1
-#define PREFERRED_DEBUGGING_TYPE DBX_DEBUG
 #endif
 
-#define DWARF2_DEBUGGING_INFO 1
-
 #define DEBUG_FRAME_SECTION	  "__DWARF,__debug_frame,regular,debug"
 #define DEBUG_INFO_SECTION	  "__DWARF,__debug_info,regular,debug"
 #define DEBUG_ABBREV_SECTION	  "__DWARF,__debug_abbrev,regular,debug"
diff --git a/gcc/config/darwin9.h b/gcc/config/darwin9.h
index 787aca72435..6576d386c12 100644
--- a/gcc/config/darwin9.h
+++ b/gcc/config/darwin9.h
@@ -18,32 +18,6 @@ You should have received a copy of the GNU General Public License
 along with GCC; see the file COPYING3.  If not see
 <http://www.gnu.org/licenses/>.  */
 
-/* Prefer DWARF2.  */
-#undef PREFERRED_DEBUGGING_TYPE
-#define PREFERRED_DEBUGGING_TYPE DWARF2_DEBUG
-#define DARWIN_PREFER_DWARF
-
-/* Since DWARF2 is default, conditions for running dsymutil are different.  */
-#undef DSYMUTIL_SPEC
-#define DSYMUTIL_SPEC \
-   "%{!fdump=*:%{!fsyntax-only:%{!c:%{!M:%{!MM:%{!E:%{!S:\
-    %{v} \
-    %{g*:%{!gstabs*:%{%:debug-level-gt(0): -idsym}}}\
-    %{.c|.cc|.C|.cpp|.cp|.c++|.cxx|.CPP|.m|.mm|.s|.f|.f90|.f95|.f03|.f77|.for|.F|.F90|.F95|.F03: \
-    %{g*:%{!gstabs*:%{%:debug-level-gt(0): -dsym}}}}}}}}}}}"
-
-/* Tell collect2 to run dsymutil for us as necessary.  */
-#define COLLECT_RUN_DSYMUTIL 1
-
-/* Only ask as for debug data if the debug style is stabs (since as doesn't
-   yet generate dwarf.)  */
-
-#undef  ASM_DEBUG_SPEC
-#define ASM_DEBUG_SPEC  "%{g*:%{%:debug-level-gt(0):%{gstabs:--gstabs}}}"
-
-#undef  ASM_DEBUG_OPTION_SPEC
-#define ASM_DEBUG_OPTION_SPEC	""
-
 #undef  ASM_OUTPUT_ALIGNED_COMMON
 #define ASM_OUTPUT_ALIGNED_COMMON(FILE, NAME, SIZE, ALIGN)		\
   do {									\