[gcc r12-10378] Darwin: Do not emit .macinfo when dsymutil cannot consume it.

[gcc r12-10378] Darwin: Do not emit .macinfo when dsymutil cannot consume it.

[Iain D Sandoe]

https://gcc.gnu.org/g:8f0f24387945ef03fcd61bf978565145bfaf3493

commit r12-10378-g8f0f24387945ef03fcd61bf978565145bfaf3493
Author: Iain Sandoe <iain@sandoe.co.uk>
Date:   Sun Mar 31 23:25:31 2024 +0100

    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:
---
 gcc/config/darwin.cc | 23 ++++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/gcc/config/darwin.cc b/gcc/config/darwin.cc
index 3cbdc97662d..6153f3c39fe 100644
--- a/gcc/config/darwin.cc
+++ b/gcc/config/darwin.cc
@@ -3376,11 +3376,6 @@ darwin_override_options (void)
 		  global_options.x_flag_objc_abi);
     }
 
-  /* 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;
-
   if (!OPTION_SET_P (dwarf_version))
     {
       /* External toolchains based on LLVM or clang 7+ have support for
@@ -3403,6 +3398,24 @@ 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