Darwin: Do not emit .macinfo when dsymutil cannot consume it.

Some verions of dsymutil do not ignore .macinfo sections, but instead
ignore the entire debug in the file.

To avoid this total loss of debug, when we detect that the debug level
is g3 and the dsymutil version cannot support it, we reduce the level
to g2 and issue a note.

This behaviour can be overidden by -gstrict-dwarf (although the objects
will contain macinfo; dsymutil will not produce a .dSYM with it).

gcc/ChangeLog:

	* config/darwin.cc (darwin_override_options): Reduce the debug
	level to 2 if dsymutil cannot handle .macinfo sections.

Signed-off-by: Iain Sandoe <iain@sandoe.co.uk>
(cherry picked from commit 3c499f8f6f7d19b21d7047efabbe6396ee1c2cac)

diff --git a/gcc/config/darwin.cc b/gcc/config/darwin.cc
index b4a7c4226c4bf455aa0b03793b975e75c7c06b37..fd2b6e872b7d5e7ed20890fbc94239052151a2c3 100644 (file)
--- a/gcc/config/darwin.cc
+++ b/gcc/config/darwin.cc
@@ -3363,10 +3363,6 @@ darwin_override_options (void)
                  global_options.x_flag_objc_abi);
     }
 
-  /* Don't emit DWARF3/4 unless specifically selected.  This is a
-     workaround for tool bugs.  */
-  if (!OPTION_SET_P (dwarf_strict))
-    dwarf_strict = 1;
   if (!OPTION_SET_P (dwarf_version))
     dwarf_version = 2;
 
@@ -3378,6 +3374,24 @@ darwin_override_options (void)
       OPTION_SET_P (dwarf_split_debug_info) = 0;
     }
 
+  /* Cases where dsymutil will exclude files with .macinfo sections; we are
+     better off forcing the debug level to 2 than completely excluding the
+     files.  If strict dwarf is set, then emit the macinfo anyway.  */
+  if (debug_info_level == DINFO_LEVEL_VERBOSE
+      && (!OPTION_SET_P (dwarf_strict) || dwarf_strict == 0)
+      && ((dsymutil_version.kind == CLANG && dsymutil_version.major >= 1500)
+         || (dsymutil_version.kind == LLVM && dsymutil_version.major >= 15)))
+    {
+      inform (input_location,
+             "%<-g3%> is not supported by the debug linker in use (set to 2)");
+      debug_info_level = DINFO_LEVEL_NORMAL;
+    }
+
+  /* Limit DWARF to the chosen version, the linker and debug linker might not
+     be able to consume newer structures.  */
+  if (!OPTION_SET_P (dwarf_strict))
+    dwarf_strict = 1;
+
   /* Do not allow unwind tables to be generated by default for m32.
      fnon-call-exceptions will override this, regardless of what we do.  */
   if (generating_for_darwin_version < 10