re PR c++/14808 ([win32] Undefined results with virtual base classes)

	PR c++/14808
	* defaults.h (TARGET_USE_LOCAL_THUNK_ALIAS_P): New macro. Default
	to 1 if ASM_OUTPUT_DEF is defined.
	* doc/tm.texi (TARGET_USE_LOCAL_THUNK_ALIAS_P): Document.
	* config/i386/cygming.h (TARGET_USE_LOCAL_THUNK_ALIAS_P): Define.
	Set to non-zero iff not a one_only decl.

	* cp/method.c (use_thunk): Test TARGET_USE_LOCAL_THUNK_ALIAS_P rather
	than ASM_OUTPUT_DEF.

From-SVN: r80525

gcc/ChangeLog

+2004-04-08  Danny Smith  <dannysmith@users.sourceforge.net>
+
+	PR c++/14808
+	* defaults.h (TARGET_USE_LOCAL_THUNK_ALIAS_P): New macro. Default
+	to 1 if ASM_OUTPUT_DEF is defined.
+	* doc/tm.texi (TARGET_USE_LOCAL_THUNK_ALIAS_P): Document.
+	* config/i386/cygming.h (TARGET_USE_LOCAL_THUNK_ALIAS_P): Define.
+	Set to non-zero iff not a one_only decl.
+
 2004-04-08  Paul Brook  <paul@codesourcery.com>
 
 	* arm.h (CLASS_LIKELY_SPILLED_P): Define.

gcc/config/i386/cygming.h

@@ -382,6 +382,11 @@ extern int i386_pe_dllimport_name_p (const char *);
       ASM_OUTPUT_DEF (STREAM, alias, IDENTIFIER_POINTER (TARGET));	\
     } while (0)
 
+/* Decide whether it is safe to use a local alias for a virtual function
+   when constructing thunks.  */
+#undef TARGET_USE_LOCAL_THUNK_ALIAS_P
+#define TARGET_USE_LOCAL_THUNK_ALIAS_P(DECL) (!DECL_ONE_ONLY (DECL))
+
 #undef TREE
 
 #ifndef BUFSIZ

gcc/cp/ChangeLog

+2004-04-08  Danny Smith  <dannysmith@users.sourceforge.net>
+
+	PR c++/14808
+	* method.c (use_thunk): Test TARGET_USE_LOCAL_THUNK_ALIAS_P rather
+	than ASM_OUTPUT_DEF.
+
 2004-04-08  Jakub Jelinek  <jakub@redhat.com>
 
 	* decl2.c (mark_used): Don't segfault if cfun != NULL but

gcc/cp/method.c

@@ -363,11 +363,10 @@ use_thunk (tree thunk_fndecl, bool emit_p)
   if (!emit_p)
     return;
 
-#ifdef ASM_OUTPUT_DEF
-  alias = make_alias_for_thunk (function);
-#else
-  alias = function;
-#endif
+  if (TARGET_USE_LOCAL_THUNK_ALIAS_P (function))
+   alias = make_alias_for_thunk (function);
+  else
+   alias = function;
 
   fixed_offset = THUNK_FIXED_OFFSET (thunk_fndecl);
   virtual_offset = THUNK_VIRTUAL_OFFSET (thunk_fndecl);
@@ -401,8 +400,8 @@ use_thunk (tree thunk_fndecl, bool emit_p)
 
   push_to_top_level ();
 
-#ifdef ASM_OUTPUT_DEF
-  if (targetm.have_named_sections)
+  if (TARGET_USE_LOCAL_THUNK_ALIAS_P (function)
+      && targetm.have_named_sections)
     {
       resolve_unique_section (function, 0, flag_function_sections);
 
@@ -414,7 +413,6 @@ use_thunk (tree thunk_fndecl, bool emit_p)
 	  DECL_SECTION_NAME (thunk_fndecl) = DECL_SECTION_NAME (function);
 	}
     }
-#endif
 
   /* The back-end expects DECL_INITIAL to contain a BLOCK, so we
      create one.  */

gcc/defaults.h

@@ -484,6 +484,16 @@ do { fputs (integer_asm_op (POINTER_SIZE / BITS_PER_UNIT, TRUE), FILE); \
 #define TARGET_VTABLE_DATA_ENTRY_DISTANCE 1
 #endif
 
+/* Decide whether it is safe to use a local alias for a virtual function
+   when constructing thunks.  */
+#ifndef TARGET_USE_LOCAL_THUNK_ALIAS_P
+#ifdef ASM_OUTPUT_DEF
+#define TARGET_USE_LOCAL_THUNK_ALIAS_P(DECL) 1
+#else
+#define TARGET_USE_LOCAL_THUNK_ALIAS_P(DECL) 0
+#endif
+#endif
+
 /* Select a format to encode pointers in exception handling data.  We
    prefer those that result in fewer dynamic relocations.  Assume no
    special support here and encode direct references.  */

gcc/doc/tm.texi

@@ -9209,3 +9209,11 @@ The parameter @var{path} is the include to register.  On Darwin
 systems, this is used for Framework includes, which have semantics
 that are different from @option{-I}.
 @end deftypefn
+
+@deftypefn {Target Hook} bool TARGET_USE_LOCAL_THUNK_ALIAS_P (tree @var{fndecl})
+This target hook returns @code{true} if it is safe to use a local alias
+for a virtual function @var{fndecl} when constructing thunks,
+@code{false} otherwise. By default, the hook returns @code{true} for all
+functions, if a target supports aliases (ie. defines
+@code{ASM_OUTPUT_DEF}), @code{false} otherwise,
+@end deftypefn