Re: Restore default 'sorry' 'TARGET_ASM_CONSTRUCTOR', 'TARGET_ASM_DESTRUCTOR' (was: [PATCH 1/3] STABS: remove -gstabs and -gxcoff functionality)

[Thomas Schwinge <thomas@codesourcery.com>]

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Hi!

On 2022-11-04T10:04:59+0100,  wrote:
> On 2022-10-12T11:21:19+0200, Martin Liška <mliska@suse.cz> wrote:
>> On 10/10/22 16:19, Thomas Schwinge wrote:
>>> attached
>>> "Restore default 'sorry' 'TARGET_ASM_CONSTRUCTOR', 'TARGET_ASM_DESTRUCTOR'".
>
>> Thanks for the fix, really appreciated!
>
> Pushed to master branch commit 4ee35c11fd328728c12f3e086ae016ca94624bf8
> "Restore default 'sorry' 'TARGET_ASM_CONSTRUCTOR', 'TARGET_ASM_DESTRUCTOR'"

..., see attached now.  ;-)


Grüße
 Thomas


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From 4ee35c11fd328728c12f3e086ae016ca94624bf8 Mon Sep 17 00:00:00 2001
From: Thomas Schwinge <thomas@codesourcery.com>
Date: Sun, 9 Oct 2022 22:39:02 +0200
Subject: [PATCH] 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'.
---
 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(+)
 create mode 100644 gcc/dbxout.cc
 create mode 100644 gcc/dbxout.h

diff --git a/gcc/Makefile.in b/gcc/Makefile.in
index f672e6ea5498..c4072d06a936 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 2fe120b38730..4cb5d02d40cd 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 000000000000..161eeb196537
--- /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 000000000000..ad0b538cabf1
--- /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 f81f8fe3bb39..1c4aa2963dc4 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
-- 
2.35.1