ada: C++ exception hierarchies: adjust for gnat-llvm

gnat-llvm doesn't support C++ imports, so arrange for the GNAT.CPP*
units to be omitted from gnat-llvm builds.

Drop G++ exception interoperability support from raise-gcc.c, so as to
not require the GNAT.CPP* units that define some of the required
symbols.

Co-Authored-By: Olivier Hainque <hainque@adacore.com>

gcc/ada/ChangeLog:

	* Makefile.rtl (LLVM_BUILD): Define based on LLVM_CONFIG.
	(GNATRTL_NONTASKING_OBJS): Make g-cpp, g-cppstd, and g-cstyin
	conditional on -gcc or -arm EH, and on no LLVM_BUILD.
	* raise-gcc.c (GXX_EH_INTEROP): Define as 0 on gnat-llvm or
	CERT, and 1 otherwise.
	(__gnat_get_cxx_dependent_exception) Omit on !GXX_EH_INTEROP.
	(__gnat_maybe_get_cxx_dependent_exception): Likewise.
	(__gnat_get_cxx_exception_type_info): Likewise.
	(__gnat_obtain_caught_object): Likewise.
	(is_handled_by): Omit eid parameter and G++ interop on
	!GXX_EH_INTEROP.  Adjust callers.

2 files changed, 47 insertions, 16 deletions

diff --git a/gcc/ada/Makefile.rtl b/gcc/ada/Makefile.rtl
index cd112d3..34bc5c8 100644
--- a/gcc/ada/Makefile.rtl
+++ b/gcc/ada/Makefile.rtl
@@ -26,6 +26,12 @@ ifndef ADAC
 ADAC=$(CC)
 endif
 
+ifeq ($(LLVM_CONFIG),)
+LLVM_BUILD := $(shell $(ADAC) -v | grep ^llvm-gcc)
+else
+LLVM_BUILD := llvm-gcc
+endif
+
 # Objects needed only for tasking
 GNATRTL_TASKING_OBJS= \
   a-dispat$(objext) \
@@ -419,9 +425,6 @@ GNATRTL_NONTASKING_OBJS= \
   g-comlin$(objext) \
   g-comver$(objext) \
   g-crc32$(objext) \
-  g-cpp$(objext) \
-  g-cppstd$(objext) \
-  g-cstyin$(objext) \
   g-ctrl_c$(objext) \
   g-curexc$(objext) \
   g-debpoo$(objext) \
@@ -3152,7 +3155,12 @@ ifeq ($(EH_MECHANISM),-gcc)
     s-excmac.ads<libgnat/s-excmac__gcc.ads \
     s-excmac.adb<libgnat/s-excmac__gcc.adb
   EXTRA_LIBGNAT_OBJS+=raise-gcc.o
-  EXTRA_GNATRTL_NONTASKING_OBJS+=g-cppexc.o s-excmac.o
+ifeq ($(LLVM_BUILD),)
+  EXTRA_GNATRTL_NONTASKING_OBJS+=g-cppexc.o s-excmac.o \
+    g-cpp$(objext) g-cppstd$(objext) g-cstyin$(objext)
+else
+  EXTRA_GNATRTL_NONTASKING_OBJS+=s-excmac.o
+endif
 endif
 
 ifeq ($(EH_MECHANISM),-arm)
@@ -3160,7 +3168,12 @@ ifeq ($(EH_MECHANISM),-arm)
     s-excmac.ads<libgnat/s-excmac__arm.ads \
     s-excmac.adb<libgnat/s-excmac__arm.adb
   EXTRA_LIBGNAT_OBJS+=raise-gcc.o
-  EXTRA_GNATRTL_NONTASKING_OBJS+=g-cppexc.o s-excmac.o
+ifeq ($(LLVM_BUILD),)
+  EXTRA_GNATRTL_NONTASKING_OBJS+=g-cppexc.o s-excmac.o \
+    g-cpp$(objext) g-cppstd$(objext) g-cstyin$(objext)
+else
+  EXTRA_GNATRTL_NONTASKING_OBJS+=s-excmac.o
+endif
 endif
 
 ifeq ($(strip $(filter-out linux%,$(target_os))),)
diff --git a/gcc/ada/raise-gcc.c b/gcc/ada/raise-gcc.c
index 1ea2963..9a75df4 100644
--- a/gcc/ada/raise-gcc.c
+++ b/gcc/ada/raise-gcc.c
@@ -48,6 +48,22 @@
 # endif
 #endif
 
+/* Arrange to include the Ada/G++ exceptions interoperability support only in
+   contexts where it is actually needed and supported, in particular not in
+   gnat-llvm, that doesn't support C++ imports.  This interoperability hasn't
+   been certified, so leave it out of CERT runtimes as well.  */
+
+#if !defined GXX_EH_INTEROP
+# if defined(__clang_major__) && defined(__clang_minor__)
+/* GNAT-LLVM does not support C++ imports.  */
+#  define GXX_EH_INTEROP 0
+# elif defined(CERT)
+#  define GXX_EH_INTEROP 0
+# else
+#  define GXX_EH_INTEROP 1
+# endif
+#endif
+
 #ifdef __cplusplus
 # include <cstdarg>
 # include <cstddef>
@@ -975,6 +991,8 @@ __gnat_exception_language_is_ada (_Unwind_Exception *except)
   return (exception_class_eq (except, GNAT_EXCEPTION_CLASS));
 }
 
+#if GXX_EH_INTEROP
+
 /* Check whether *THROWN_PTR of EXCEPT_TYPEINFO is to be caught by a
    CHOICE_TYPEINFO handler under LANG convention.
    Implemented by GNAT.CPP_Exception.Convert_Caught_Object.  */
@@ -1099,20 +1117,17 @@ __gnat_obtain_caught_object (int *success_p, void **thrown_ptr_p,
     }
 }
 
+#endif /* GXX_EH_INTEROP */
+
 /* Return how CHOICE matches PROPAGATED_EXCEPTION.  */
 
 static enum action_kind
 is_handled_by (Exception_Id choice,
-#ifndef CERT
+#if GXX_EH_INTEROP
 	       Exception_Id *eid,
-#endif
+#endif /* GXX_EH_INTEROP */
 	       _Unwind_Exception *propagated_exception)
 {
-#ifndef CERT
-  char lang;
-  bool primary;
-#endif
-
   /* All others choice match everything.  */
   if (choice == GNAT_ALL_OTHERS)
     return handler;
@@ -1144,7 +1159,10 @@ is_handled_by (Exception_Id choice,
       )
     return handler;
 
-#ifndef CERT
+#if GXX_EH_INTEROP
+  char lang;
+  bool primary;
+
   /* C++ exception occurrences with exact (C) or base (B) type matching.  */
   if (((primary = exception_class_eq (propagated_exception,
 				      CXX_EXCEPTION_CLASS))
@@ -1171,7 +1189,7 @@ is_handled_by (Exception_Id choice,
 	  return handler;
 	}
     }
-#endif
+#endif /* GXX_EH_INTEROP */
 
   return nothing;
 }
@@ -1259,9 +1277,9 @@ get_action_description_for (_Unwind_Ptr ip,
 		    = (Exception_Id) get_ttype_entry_for (region, ar_filter);
 
 		  act = is_handled_by (choice,
-#ifndef CERT
+#if GXX_EH_INTEROP
 				       eid,
-#endif
+#endif /* GXX_EH_INTEROP */
 				       uw_exception);
                   if (act != nothing)
                     {