[gcc r13-3649] Restore default 'sorry' 'TARGET_ASM_CONSTRUCTOR', 'TARGET_ASM_DESTRUCTOR'

[gcc r13-3649] Restore default 'sorry' 'TARGET_ASM_CONSTRUCTOR', 'TARGET_ASM_DESTRUCTOR'

[Thomas Schwinge]

https://gcc.gnu.org/g:4ee35c11fd328728c12f3e086ae016ca94624bf8

commit r13-3649-g4ee35c11fd328728c12f3e086ae016ca94624bf8
Author: Thomas Schwinge <thomas@codesourcery.com>
Date:   Sun Oct 9 22:39:02 2022 +0200

    Restore default 'sorry' 'TARGET_ASM_CONSTRUCTOR', 'TARGET_ASM_DESTRUCTOR'
    
    ... that got lost in commit 7e0db0cdf01e9c885a29cb37415f5bc00d90c029
    "STABS: remove -gstabs and -gxcoff functionality".
    
    Previously, if a back end was not 'USE_COLLECT2', nor manually defined
    'TARGET_ASM_CONSTRUCTOR', 'TARGET_ASM_DESTRUCTOR', or got pointed to the
    respective 'default_[...]' functions due to 'CTORS_SECTION_ASM_OP',
    'DTORS_SECTION_ASM_OP', or 'TARGET_ASM_NAMED_SECTION', it got pointed to
    'default_stabs_asm_out_constructor', 'default_stabs_asm_out_destructor'.
    These would emit 'sorry' for any global constructor/destructor they're
    run into.
    
    This is now gone, and thus in such a back end configuration case
    'TARGET_ASM_CONSTRUCTOR', 'TARGET_ASM_DESTRUCTOR' don't get defined
    anymore, and thus the subsequently following:
    
        #if !defined(TARGET_HAVE_CTORS_DTORS)
        # if defined(TARGET_ASM_CONSTRUCTOR) && defined(TARGET_ASM_DESTRUCTOR)
        # define TARGET_HAVE_CTORS_DTORS true
        # endif
        #endif
    
    ... doesn't define 'TARGET_HAVE_CTORS_DTORS' anymore, and thus per my
    understanding, 'gcc/final.cc:rest_of_handle_final':
    
        if (DECL_STATIC_CONSTRUCTOR (current_function_decl)
            && targetm.have_ctors_dtors)
          targetm.asm_out.constructor (XEXP (DECL_RTL (current_function_decl), 0),
                                       decl_init_priority_lookup
                                         (current_function_decl));
        if (DECL_STATIC_DESTRUCTOR (current_function_decl)
            && targetm.have_ctors_dtors)
          targetm.asm_out.destructor (XEXP (DECL_RTL (current_function_decl), 0),
                                      decl_fini_priority_lookup
                                        (current_function_decl));
    
    ... simply does nothing anymore for a 'DECL_STATIC_CONSTRUCTOR',
    'DECL_STATIC_DESTRUCTOR'.
    
    This, effectively, means that GCC/nvptx now suddenly appears to "support"
    global constructors/destructors, which means that a ton of test cases now
    erroneously PASS that previously used to FAIL:
    
        sorry, unimplemented: global constructors not supported on this target
    
    Of course, such support didn't magically happen due to
    "STABS: remove -gstabs and -gxcoff functionality", so this is bad.  And,
    corresponding execution testing then regularly FAILs (due to the global
    constructor/destructor functions never being invoked), for example:
    
        [-UNSUPPORTED:-]{+PASS:+} gcc.dg/initpri1.c {+(test for excess errors)+}
        {+FAIL: gcc.dg/initpri1.c execution test+}
    
        [-UNSUPPORTED:-]{+PASS:+} g++.dg/special/conpr-1.C {+(test for excess errors)+}
        {+FAIL: g++.dg/special/conpr-1.C execution test+}
    
    To restore the previous GCC/nvptx behavior, for traceability, this simply
    restores the previous code, stripped down to the bare minimum.
    
            gcc/
            * Makefile.in (OBJS): Add 'dbxout.o'.
            * config/nvptx/nvptx.cc: '#include "dbxout.h"'.
            * dbxout.cc: New.
            * dbxout.h: Likewise.
            * target-def.h (TARGET_ASM_CONSTRUCTOR, TARGET_ASM_DESTRUCTOR):
            Default to 'default_stabs_asm_out_constructor',
            'default_stabs_asm_out_destructor'.

Diff:
---
 gcc/Makefile.in           |  1 +
 gcc/config/nvptx/nvptx.cc |  1 +
 gcc/dbxout.cc             | 43 +++++++++++++++++++++++++++++++++++++++++++
 gcc/dbxout.h              | 25 +++++++++++++++++++++++++
 gcc/target-def.h          |  4 ++++
 5 files changed, 74 insertions(+)

diff --git a/gcc/Makefile.in b/gcc/Makefile.in
index f672e6ea549..c4072d06a93 100644
--- a/gcc/Makefile.in
+++ b/gcc/Makefile.in
@@ -1355,6 +1355,7 @@ OBJS = \
 	data-streamer.o \
 	data-streamer-in.o \
 	data-streamer-out.o \
+	dbxout.o \
 	dbgcnt.o \
 	dce.o \
 	ddg.o \
diff --git a/gcc/config/nvptx/nvptx.cc b/gcc/config/nvptx/nvptx.cc
index 2fe120b3873..4cb5d02d40c 100644
--- a/gcc/config/nvptx/nvptx.cc
+++ b/gcc/config/nvptx/nvptx.cc
@@ -52,6 +52,7 @@
 #include "tm-preds.h"
 #include "tm-constrs.h"
 #include "langhooks.h"
+#include "dbxout.h"
 #include "cfgrtl.h"
 #include "gimple.h"
 #include "stor-layout.h"
diff --git a/gcc/dbxout.cc b/gcc/dbxout.cc
new file mode 100644
index 00000000000..161eeb19653
--- /dev/null
+++ b/gcc/dbxout.cc
@@ -0,0 +1,43 @@
+/* Copyright (C) 1987-2022 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+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/>.  */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "diagnostic-core.h"
+#include "dbxout.h"
+
+/* Record an element in the table of global destructors.  SYMBOL is
+   a SYMBOL_REF of the function to be called; PRIORITY is a number
+   between 0 and MAX_INIT_PRIORITY.  */
+
+void
+default_stabs_asm_out_destructor (rtx symbol ATTRIBUTE_UNUSED,
+				  int priority ATTRIBUTE_UNUSED)
+{
+  sorry ("global destructors not supported on this target");
+}
+
+/* Likewise for global constructors.  */
+
+void
+default_stabs_asm_out_constructor (rtx symbol ATTRIBUTE_UNUSED,
+				   int priority ATTRIBUTE_UNUSED)
+{
+  sorry ("global constructors not supported on this target");
+}
diff --git a/gcc/dbxout.h b/gcc/dbxout.h
new file mode 100644
index 00000000000..ad0b538cabf
--- /dev/null
+++ b/gcc/dbxout.h
@@ -0,0 +1,25 @@
+/* Copyright (C) 1998-2022 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+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/>.  */
+
+#ifndef GCC_DBXOUT_H
+#define GCC_DBXOUT_H
+
+extern void default_stabs_asm_out_destructor (rtx, int);
+extern void default_stabs_asm_out_constructor (rtx, int);
+
+#endif /* GCC_DBXOUT_H */
diff --git a/gcc/target-def.h b/gcc/target-def.h
index f81f8fe3bb3..1c4aa2963dc 100644
--- a/gcc/target-def.h
+++ b/gcc/target-def.h
@@ -62,6 +62,8 @@
 # else
 #  ifdef TARGET_ASM_NAMED_SECTION
 #   define TARGET_ASM_CONSTRUCTOR default_named_section_asm_out_constructor
+#  else
+#   define TARGET_ASM_CONSTRUCTOR default_stabs_asm_out_constructor
 #  endif
 # endif
 #endif
@@ -72,6 +74,8 @@
 # else
 #  ifdef TARGET_ASM_NAMED_SECTION
 #   define TARGET_ASM_DESTRUCTOR default_named_section_asm_out_destructor
+#  else
+#   define TARGET_ASM_DESTRUCTOR default_stabs_asm_out_destructor
 #  endif
 # endif
 #endif