Eric Botcazou - [PATCH] Fix PR c++/14962 (original) (raw)

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• From: Eric Botcazou
• To: gcc-patches at gcc dot gnu dot org
• Date: Wed, 5 May 2004 15:37:32 +0200
• Subject: [PATCH] Fix PR c++/14962

Hi,

This is a regression that has been present since GCC 3.1 on Solaris-based platforms: #pragma redefine_extname doesn't work under certain circumstances with the C++ compiler, while it does with the C compiler. This is annoying because the circumstances at stake occur for the large file support in the Solaris system headers.

The situation is as follows:

extern "C" {

struct old_name { int i; };

#pragma redefine_extname old_name new_name

int old_name(void);

}

References to the function 'old_name' are still emitted as 'old_name' in the assembly file, while they should be emitted as 'new_name', like with the C compiler.

The problem is in c-pragma.c:handle_pragma_redefine_extname

decl = identifier_global_value (oldname); if (decl && TREE_CODE_CLASS (TREE_CODE (decl)) == 'd') { if (DECL_ASSEMBLER_NAME_SET_P (decl) && DECL_ASSEMBLER_NAME (decl) != newname) warning ("#pragma redefine_extname conflicts with declaration"); change_decl_assembler_name (decl, newname); } else add_to_renaming_pragma_list(oldname, newname);

Because of the 'struct old_name' definition, 'oldname' already exists when the pragma is parsed and is a tag for the C compiler and a type for the C++ compiler.

In the first case (C compiler), identifier_global_value returns 0 so add_to_renaming_pragma_list is invoked and all works fine. In the second case, identifier_global_value returns a TYPE_DECL, which means the condition is true and add_to_renaming_pragma_list is not invoked.

The proposed fix is to restrict the condition to the DECLs that have an assembler name. See the patch for the list. Bootstrapped/regtested (mainline) on SPARC/Solaris 2.5.1, 2.6, 7, 8 and 9.

OK for mainline and 3.4 branch?

2004-05-05 Eric Botcazou ebotcazou@libertysurf.fr

PR c++/14962
* c-pragma.c (handle_pragma_redefine_extname): Only change
the assembler name of DECLs that have one.

2004-05-05 Eric Botcazou ebotcazou@libertysurf.fr

* g++.dg/other/pragma-re-2.C: New test.

-- Eric Botcazou

Index: c-pragma.c

RCS file: /cvs/gcc/gcc/gcc/c-pragma.c,v retrieving revision 1.66.2.1 diff -u -p -r1.66.2.1 c-pragma.c --- c-pragma.c 23 Jan 2004 23:35:53 -0000 1.66.2.1 +++ c-pragma.c 4 May 2004 12:15:09 -0000 @@ -377,7 +377,10 @@ handle_pragma_redefine_extname (cpp_read warning ("junk at end of #pragma redefine_extname");

decl = identifier_global_value (oldname);

• if (decl && TREE_CODE_CLASS (TREE_CODE (decl)) == 'd')

• if (decl && (TREE_CODE (decl) == FUNCTION_DECL

•       || TREE_CODE (decl) == LABEL_DECL

•       || TREE_CODE (decl) == CONST_DECL

•       || TREE_CODE (decl) == VAR_DECL))
  {
    if (DECL_ASSEMBLER_NAME_SET_P (decl)
    && DECL_ASSEMBLER_NAME (decl) != newname)

/* PR c++/14962 / / Originator: phil@fsel.com */

/* { dg-do compile { target --solaris* } } / / { dg-final { scan-assembler "new_name" } } / / { dg-final { scan-assembler-not "old_name" } } */

#ifndef __PRAGMA_REDEFINE_EXTNAME #error #endif

extern "C" {

struct old_name { int i; };

#pragma redefine_extname old_name new_name

int old_name(void);

}

int foo(void) { return old_name(); }

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