2020-07-30  Richard Biener  <rguenther@suse.de>

	PR debug/96383

	* langhooks-def.h (lhd_finalize_early_debug): Declare.

	(LANG_HOOKS_FINALIZE_EARLY_DEBUG): Define.

	(LANG_HOOKS_INITIALIZER): Amend.

	* langhooks.c: Include cgraph.h and debug.h.

	(lhd_finalize_early_debug): Default implementation from

	former code in finalize_compilation_unit.

	* langhooks.h (lang_hooks::finalize_early_debug): Add.

	* cgraphunit.c (symbol_table::finalize_compilation_unit):

	Call the finalize_early_debug langhook.

gcc/c-family/

	* c-common.h (c_common_finalize_early_debug): Declare.

	* c-common.c: Include debug.h.

	(c_common_finalize_early_debug): finalize_early_debug langhook

	implementation generating debug for extern declarations.

gcc/c/

	* c-objc-common.h (LANG_HOOKS_FINALIZE_EARLY_DEBUG):

	Define to c_common_finalize_early_debug.

gcc/cp/

	* cp-objcp-common.h (LANG_HOOKS_FINALIZE_EARLY_DEBUG):

	Define to c_common_finalize_early_debug.

gcc/testsuite/

	* gcc.dg/debug/dwarf2/pr96383-1.c: New testcase.

	* gcc.dg/debug/dwarf2/pr96383-2.c: Likewise.

libstdc++-v3/

	* testsuite/20_util/assume_aligned/3.cc: Use -g0.

--- gcc/c-family/c-common.c

+++ gcc/c-family/c-common.c

@@ -50,6 +50,7 @@ along with GCC; see the file COPYING3.  If not see

 #include "spellcheck.h"

 #include "c-spellcheck.h"

 #include "selftest.h"

+#include "debug.h"

 cpp_reader *parse_in;		/* Declared in c-pragma.h.  */

@@ -9086,4 +9087,20 @@ braced_lists_to_strings (tree type, tree ctor)

   return braced_lists_to_strings (type, ctor, false);

 }

+

+/* Emit debug for functions before finalizing early debug.  */

+

+void

+c_common_finalize_early_debug (void)

+{

+  /* Emit early debug for reachable functions, and by consequence,

+     locally scoped symbols.  Also emit debug for extern declared

+     functions that are still reachable at this point.  */

+  struct cgraph_node *cnode;

+  FOR_EACH_FUNCTION (cnode)

+    if (!cnode->alias && !cnode->thunk.thunk_p

+	&& (cnode->has_gimple_body_p () || !DECL_IS_BUILTIN (cnode->decl)))

+      (*debug_hooks->early_global_decl) (cnode->decl);

+}

+

 #include "gt-c-family-c-common.h"

--- gcc/c-family/c-common.h

+++ gcc/c-family/c-common.h

@@ -885,6 +885,8 @@ extern bool bool_promoted_to_int_p (tree);

 extern tree fold_for_warn (tree);

 extern tree c_common_get_narrower (tree, int *);

 extern bool get_attribute_operand (tree, unsigned HOST_WIDE_INT *);

+extern void c_common_finalize_early_debug (void);

+

 #define c_sizeof(LOC, T)  c_sizeof_or_alignof_type (LOC, T, true, false, 1)

 #define c_alignof(LOC, T) c_sizeof_or_alignof_type (LOC, T, false, false, 1)

--- gcc/c/c-objc-common.h

+++ gcc/c/c-objc-common.h

@@ -65,6 +65,8 @@ along with GCC; see the file COPYING3.  If not see

   c_simulate_builtin_function_decl

 #undef LANG_HOOKS_EMITS_BEGIN_STMT

 #define LANG_HOOKS_EMITS_BEGIN_STMT true

+#undef LANG_HOOKS_FINALIZE_EARLY_DEBUG

+#define LANG_HOOKS_FINALIZE_EARLY_DEBUG c_common_finalize_early_debug

 /* Attribute hooks.  */

 #undef LANG_HOOKS_COMMON_ATTRIBUTE_TABLE

--- gcc/cgraphunit.c

+++ gcc/cgraphunit.c

@@ -2998,11 +2998,9 @@ symbol_table::finalize_compilation_unit (void)

   if (!seen_error ())

     {

-      /* Emit early debug for reachable functions, and by consequence,

-	 locally scoped symbols.  */

-      struct cgraph_node *cnode;

-      FOR_EACH_FUNCTION_WITH_GIMPLE_BODY (cnode)

-	(*debug_hooks->early_global_decl) (cnode->decl);

+      /* Give the frontends the chance to emit early debug based on

+	 what is still reachable in the TU.  */

+      (*lang_hooks.finalize_early_debug) ();

       /* Clean up anything that needs cleaning up after initial debug

 	 generation.  */

--- gcc/cp/cp-objcp-common.h

+++ gcc/cp/cp-objcp-common.h

@@ -115,6 +115,8 @@ extern tree cxx_simulate_enum_decl (location_t, const char *,

 #define LANG_HOOKS_BLOCK_MAY_FALLTHRU cxx_block_may_fallthru

 #undef LANG_HOOKS_EMITS_BEGIN_STMT

 #define LANG_HOOKS_EMITS_BEGIN_STMT true

+#undef LANG_HOOKS_FINALIZE_EARLY_DEBUG

+#define LANG_HOOKS_FINALIZE_EARLY_DEBUG c_common_finalize_early_debug

 /* Attribute hooks.  */

 #undef LANG_HOOKS_COMMON_ATTRIBUTE_TABLE

--- gcc/langhooks-def.h

+++ gcc/langhooks-def.h

@@ -92,6 +92,7 @@ extern const char *lhd_get_substring_location (const substring_loc &,

 					       location_t *out_loc);

 extern int lhd_decl_dwarf_attribute (const_tree, int);

 extern int lhd_type_dwarf_attribute (const_tree, int);

+extern void lhd_finalize_early_debug (void);

 #define LANG_HOOKS_NAME			"GNU unknown"

 #define LANG_HOOKS_IDENTIFIER_SIZE	sizeof (struct lang_identifier)

@@ -139,6 +140,7 @@ extern int lhd_type_dwarf_attribute (const_tree, int);

 #define LANG_HOOKS_EMITS_BEGIN_STMT	false

 #define LANG_HOOKS_RUN_LANG_SELFTESTS   lhd_do_nothing

 #define LANG_HOOKS_GET_SUBSTRING_LOCATION lhd_get_substring_location

+#define LANG_HOOKS_FINALIZE_EARLY_DEBUG lhd_finalize_early_debug

 /* Attribute hooks.  */

 #define LANG_HOOKS_ATTRIBUTE_TABLE		NULL

@@ -364,7 +366,8 @@ extern void lhd_end_section (void);

   LANG_HOOKS_CUSTOM_FUNCTION_DESCRIPTORS, \

   LANG_HOOKS_EMITS_BEGIN_STMT, \

   LANG_HOOKS_RUN_LANG_SELFTESTS, \

-  LANG_HOOKS_GET_SUBSTRING_LOCATION \

+  LANG_HOOKS_GET_SUBSTRING_LOCATION, \

+  LANG_HOOKS_FINALIZE_EARLY_DEBUG \

 }

 #endif /* GCC_LANG_HOOKS_DEF_H */

--- gcc/langhooks.c

+++ gcc/langhooks.c

@@ -36,6 +36,8 @@ along with GCC; see the file COPYING3.  If not see

 #include "output.h"

 #include "timevar.h"

 #include "stor-layout.h"

+#include "cgraph.h"

+#include "debug.h"

 /* Do nothing; in many cases the default hook.  */

@@ -866,6 +868,18 @@ lhd_unit_size_without_reusable_padding (tree t)

   return TYPE_SIZE_UNIT (t);

 }

+/* Default implementation for the finalize_early_debug hook.  */

+

+void

+lhd_finalize_early_debug (void)

+{

+  /* Emit early debug for reachable functions, and by consequence,

+     locally scoped symbols.  */

+  struct cgraph_node *cnode;

+  FOR_EACH_FUNCTION_WITH_GIMPLE_BODY (cnode)

+    (*debug_hooks->early_global_decl) (cnode->decl);

+}

+

 /* Returns true if the current lang_hooks represents the GNU C frontend.  */

 bool

--- gcc/langhooks.h

+++ gcc/langhooks.h

@@ -580,6 +580,9 @@ struct lang_hooks

   const char *(*get_substring_location) (const substring_loc &,

 					 location_t *out_loc);

+  /* Invoked before the early_finish debug hook is invoked.  */

+  void (*finalize_early_debug) (void);

+

   /* Whenever you add entries here, make sure you adjust langhooks-def.h

      and langhooks.c accordingly.  */

 };

--- gcc/testsuite/gcc.dg/debug/dwarf2/pr96383-1.c

+++ gcc/testsuite/gcc.dg/debug/dwarf2/pr96383-1.c

@@ -0,0 +1,17 @@

+/* { dg-do compile } */

+/* { dg-options "-g -gdwarf -dA" } */

+

+extern void foo (int);

+extern void unusedbar (int);

+

+int main()

+{

+  foo (1);

+}

+

+/* We want subprogram DIEs for both foo and main and a DIE for

+   the formal parameter of foo.  We do not want a DIE for

+   unusedbar.  */

+/* { dg-final { scan-assembler-times "DW_TAG_subprogram" 4 } } */

+/* { dg-final { scan-assembler-times "DW_TAG_formal_parameter" 2 } } */

+/* { dg-final { scan-assembler-not "unusedbar" } } */

--- gcc/testsuite/gcc.dg/debug/dwarf2/pr96383-2.c

+++ gcc/testsuite/gcc.dg/debug/dwarf2/pr96383-2.c

@@ -0,0 +1,17 @@

+/* { dg-do compile } */

+/* { dg-options "-g -O2 -gdwarf -dA" } */

+

+extern void foo (int);

+extern void unusedbar (int);

+

+int main()

+{

+  foo (1);

+}

+

+/* We want subprogram DIEs for both foo and main and a DIE for

+   the formal parameter of foo.  We do not want a DIE for

+   unusedbar.  */

+/* { dg-final { scan-assembler-times "DW_TAG_subprogram" 4 } } */

+/* { dg-final { scan-assembler-times "DW_TAG_formal_parameter" 2 } } */

+/* { dg-final { scan-assembler-not "unusedbar" } } */

--- libstdc++-v3/testsuite/20_util/assume_aligned/3.cc

+++ libstdc++-v3/testsuite/20_util/assume_aligned/3.cc

@@ -15,7 +15,7 @@

 // with this library; see the file COPYING3.  If not see

 // <http://www.gnu.org/licenses/>.

-// { dg-options "-std=gnu++2a -O2" }

+// { dg-options "-std=gnu++2a -O2 -g0" }

 // { dg-do compile { target c++2a } }

 // { dg-final { scan-assembler-not "undefined" } }