re PR target/21275 (gcc 4.0.0 crash with mingw when using stdout in global var)

	PR middle-end/21275
	PR middle-end/21766
	* target.h (struct gcc_target): Add valid_dllimport_attribute_p
	target hook.
	(struct cxx): Add adjust_class_at_definition target hook.
	* target-def.h: (TARGET_VALID_DLLIMPORT_ATTRIBUTE_P): New define,
	defaulting to hook_bool_tree_true. Add to TARGET_INITIALIZER
	(TARGET_CXX_ADJUST_CLASS_AT_DEFINITION): New define, defaulting to
	hook_void_tree. Add to TARGET_CXX.
	* tree.h (struct decl_with_vis): Rename non_addr_const_p field to
	dllimport_flag.
	(DECL_NON_ADDR_CONSTANT_P): Replace with DECL_DLLIMPORT_P macro.
	* tree.c (merge_dllimport_decl_attributes): Check DECL_DLLIMPORT_P
	instead of attribute. Check for dllexport override.  Warn if
	inconsistent dll linkage. Don't lose old dllimport if decl has
	had address referenced.   Tweak lookup of dllimport atribute.
	(handle_dll_attribute): Check targetm.valid_dllimport_attribute_p
	for target specific rules.  Don't add dllimport attribute if
	DECL_DECLARED_INLINE_P.  Set DECL_DLLIMPORT_P when adding
	dllimport attribute.
	(staticp): Replace DECL_NON_ADDR_CONSTANT_P with DECL_DLLIMPORT_P.
	* varasm.c (initializer_constant_valid_p): Replace
	DECL_NON_ADDR_CONSTANT_P with DECL_DLLIMPORT_P

	PR target/21801
	PR target/23589
	* config.gcc (i[34567]86-*-cygwin*): Add winnt-cxx.o to
	'cxx_target_objs', winnt-stubs,o to 'extra_objs'.
	(i[34567]86-*-mingw32*): Likewise.

	* doc/tm.texi (TARGET_CXX_ADJUST_CLASS_AT_DEFINITION): Document.
	(TARGET_VALID_DLLIMPORT_ATTRIBUTE_P): Document.

	* config/i386/winnt.c (i386_pe_dllimport_p): Factor out
	C++-specific code. Change return value to bool.
	(i386_pe_dllimport_p): Likewise.
	(associated_type): Simplify and make language-independent
	(i386_pe_encode_section_info): Replace override of ambiguous
	dllimport symbol refs with a gcc_assert.
	(i386_pe_valid_dllimport_attribute_p): Define.
	* config/i386/winnt-cxx.c: New file. Define C++ versions of
	i386_pe_type_dllimport_p, i386_pe_type_dllexport_p,
	i386_pe_adjust_class_at_definition.
	* config/i386/winnt-stubs.c: New file. Define stub versions of
	lang-specific functions.
	* config/i386/i386-protos.h: Declare winnt-[cxx|stubs].c functions
	i386_pe_type_dllimport_p, i386_pe_type_dllexport_p,
	i386_pe_adjust_class_at_definition.
	(i386_pe_valid_dllimport_attribute_p): Declare.
	* config/i386/cygming.h (TARGET_VALID_DLLIMPORT_ATTRIBUTE_P): Define.
	(TARGET_CXX_ADJUST_CLASS_AT_DEFINITION): Define.
	* config/i386/t-cygming: Add rules for winnt-cxx.o, winnt-stubs.o.

	PR target/19704
	* config/i386/i386.c (ix86_function_ok_for_sibcall): Replace test for
	dllimport attribute with test of DECL_DLLIMPORT_P.


cp
	PR target/21801
	PR target/23589
	* class.c (finish_struct_1): Call
	targetm.cxx.adjust_class_at_definition.


testsuite
	* gcc.dg/dll-2.c: Add tests for warnings.
	* gcc.dg/dll-3.c: Likewise.
	* gcc.dg/dll-4.c: Likewise.

	* g++.dg/ext/dllimport1.C: Adjust tests for warnings.
	* g++.dg/ext/dllimport2.C: Likewise.
	* g++.dg/ext/dllimport3.C: Likewise.
	* g++.dg/ext/dllimport7.C: Likewise.
	* g++.dg/ext/dllimport8.C: Likewise.
	* g++.dg/ext/dllimport9.C: Likewise.

From-SVN: r105332

1 files changed, 65 insertions, 19 deletions

diff --git a/gcc/tree.c b/gcc/tree.c
index 333c745..946bf90 100644
--- a/gcc/tree.c
+++ b/gcc/tree.c
@@ -1797,7 +1797,7 @@ staticp (tree arg)
     case VAR_DECL:
       return ((TREE_STATIC (arg) || DECL_EXTERNAL (arg))
 	      && ! DECL_THREAD_LOCAL_P (arg)
-	      && ! DECL_NON_ADDR_CONST_P (arg)
+	      && ! DECL_DLLIMPORT_P (arg)
 	      ? arg : NULL);
 
     case CONST_DECL:
@@ -3478,31 +3478,66 @@ tree
 merge_dllimport_decl_attributes (tree old, tree new)
 {
   tree a;
-  int delete_dllimport_p;
-
-  old = DECL_ATTRIBUTES (old);
-  new = DECL_ATTRIBUTES (new);
+  int delete_dllimport_p = 1;
 
   /* What we need to do here is remove from `old' dllimport if it doesn't
      appear in `new'.  dllimport behaves like extern: if a declaration is
      marked dllimport and a definition appears later, then the object
-     is not dllimport'd.  */
-  if (lookup_attribute ("dllimport", old) != NULL_TREE
-      && lookup_attribute ("dllimport", new) == NULL_TREE)
-    delete_dllimport_p = 1;
+     is not dllimport'd.  We also remove a `new' dllimport if the old list
+     contains dllexport:  dllexport always overrides dllimport, regardless
+     of the order of declaration.  */     
+  if (!VAR_OR_FUNCTION_DECL_P (new))
+    delete_dllimport_p = 0;
+  else if (DECL_DLLIMPORT_P (new)
+     	   && lookup_attribute ("dllexport", DECL_ATTRIBUTES (old)))
+    { 
+      DECL_DLLIMPORT_P (new) = 0;
+      warning (OPT_Wattributes, "%q+D already declared with dllexport attribute: "
+	      "dllimport ignored", new);
+    }
+  else if (DECL_DLLIMPORT_P (old) && !DECL_DLLIMPORT_P (new))
+    {
+      /* Warn about overriding a symbol that has already been used. eg:
+           extern int __attribute__ ((dllimport)) foo;
+	   int* bar () {return &foo;}
+	   int foo;
+      */
+      if (TREE_USED (old))
+	{
+	  warning (0, "%q+D redeclared without dllimport attribute "
+		   "after being referenced with dll linkage", new);
+	  /* If we have used a variable's address with dllimport linkage,
+	      keep the old DECL_DLLIMPORT_P flag: the ADDR_EXPR using the
+	      decl may already have had TREE_INVARIANT and TREE_CONSTANT
+	      computed.
+	      We still remove the attribute so that assembler code refers
+	      to '&foo rather than '_imp__foo'.  */
+	  if (TREE_CODE (old) == VAR_DECL && TREE_ADDRESSABLE (old))
+	    DECL_DLLIMPORT_P (new) = 1;
+	}
+
+      /* Let an inline definition silently override the external reference,
+	 but otherwise warn about attribute inconsistency.  */ 
+      else if (TREE_CODE (new) == VAR_DECL
+	       || !DECL_DECLARED_INLINE_P (new))
+	warning (OPT_Wattributes, "%q+D redeclared without dllimport attribute: "
+		  "previous dllimport ignored", new);
+    }
   else
     delete_dllimport_p = 0;
 
-  a = merge_attributes (old, new);
+  a = merge_attributes (DECL_ATTRIBUTES (old), DECL_ATTRIBUTES (new));
 
-  if (delete_dllimport_p)
+  if (delete_dllimport_p) 
     {
       tree prev, t;
-
+      const size_t attr_len = strlen ("dllimport"); 
+     
       /* Scan the list for dllimport and delete it.  */
       for (prev = NULL_TREE, t = a; t; prev = t, t = TREE_CHAIN (t))
 	{
-	  if (is_attribute_p ("dllimport", TREE_PURPOSE (t)))
+	  if (is_attribute_with_length_p ("dllimport", attr_len,
+					  TREE_PURPOSE (t)))
 	    {
 	      if (prev == NULL_TREE)
 		a = TREE_CHAIN (a);
@@ -3549,18 +3584,26 @@ handle_dll_attribute (tree * pnode, tree name, tree args, int flags,
      any damage.  */
   if (is_attribute_p ("dllimport", name))
     {
+      /* Honor any target-specific overides. */ 
+      if (!targetm.valid_dllimport_attribute_p (node))
+	*no_add_attrs = true;
+
+     else if (TREE_CODE (node) == FUNCTION_DECL
+	        && DECL_DECLARED_INLINE_P (node))
+	{
+	  warning (OPT_Wattributes, "inline function %q+D declared as "
+		  " dllimport: attribute ignored", node); 
+	  *no_add_attrs = true;
+	}
       /* Like MS, treat definition of dllimported variables and
-	 non-inlined functions on declaration as syntax errors.  We
-	 allow the attribute for function definitions if declared
-	 inline.  */
-      if (TREE_CODE (node) == FUNCTION_DECL  && DECL_INITIAL (node)
-          && !DECL_DECLARED_INLINE_P (node))
+	 non-inlined functions on declaration as syntax errors. */
+     else if (TREE_CODE (node) == FUNCTION_DECL && DECL_INITIAL (node))
 	{
 	  error ("function %q+D definition is marked dllimport", node);
 	  *no_add_attrs = true;
 	}
 
-      else if (TREE_CODE (node) == VAR_DECL)
+     else if (TREE_CODE (node) == VAR_DECL)
 	{
 	  if (DECL_INITIAL (node))
 	    {
@@ -3577,6 +3620,9 @@ handle_dll_attribute (tree * pnode, tree name, tree args, int flags,
 	  if (current_function_decl != NULL_TREE && !TREE_STATIC (node))
 	    TREE_PUBLIC (node) = 1;
 	}
+
+      if (*no_add_attrs == false)
+        DECL_DLLIMPORT_P (node) = 1;
     }
 
   /*  Report error if symbol is not accessible at global scope.  */