IMA: re-enable

IMA: re-enable

[Zack Weinberg]

Here at last is the patch to turn IMA back on.  All the prep work paid
off; there's only a small handful of bugfixes in here.  This has been
tested as follows:

 - Ordinary bootstrap and testsuite run on i686-linux.
 - Andrew Pinski's IMA testsuite, at -O0 and -O2.

 - The equivalent of an --enable-intermodule bootstrap, C only, on
   amd64-linux.  Due to bugs in the Makefile which I was not able to
   solve, an actual --enable-intermodule bootstrap does not work; it
   tries to build libbackend.o with the host compiler, in the middle
   of the libgcc build, after having built cc1 already the normal way.
   Instead, I did 'make stage1_copy' in a normal configuration, then
   edited the Makefile to activate the special dependencies for
   libbackend.a, and then proceeded with 'make bootstrap'.  I did not
   run the testsuite with the resultant compiler.

Bugs exposed during testing mostly had to do with handling of 
'extern inline' and 'static inline' functions from system headers (so
encountered in multiple translation units).

File/line reports in diagnostics for the second and successive
translation units are completely bogus.  I do not think this is worth
bothering to fix until Per is done with his fileline project; it may
magically go away in the course of that, and even if it doesn't, it
will be easier to fix then.

I did not have time to write a dejagnu harness for the IMA testsuite,
but I will take it with me to Los Angeles and work on it there.

The change to noncompile/init-4.c eliminates a dg-error marker for a
diagnostic that shouldn't have been being emitted in the first place.
I'm not sure why it was being emitted; the intent of the code is
clearly not to.

Moving the cpp_undef_all from pop_file_scope to c_common_parse_file is
strictly a performance hack - it's a high-cost operation and doesn't
need to be done in the single-translation-unit case.

zw

2004-07-09  Zack Weinberg  <zack@codesourcery.com>
            Andrew Pinski  <apinski@apple.com>

        * c-opts.c (c_common_post_options): Force unit-at-a-time mode
        on when we have more than one input file.
        (c_common_parse_file): Restore loop over all input files.
        Clarify diagnostic for -dy when YYDEBUG wasn't defined.

        * c-decl.c (set_type_context): New function.
        (pop_scope): Use it to set context of types.  When we
        encounter a TYPE_DECL, set the context of the attached type too.
        (pop_file_scope): Don't call cpp_undef_all here.
        (diagnose_mismatched_decls): Do not complain about a second
        definition of an 'extern inline' function if it's not in the
        same translation unit.  Do not complain about inline
        declaration after use if the use was in a different
        translation unit.
        (merge_decls): Don't clobber olddecl's DECL_CONTEXT.
        (pushdecl): Do not put DECL_EXTERNAL, !TREE_PUBLIC decls in
        the external scope.
        (pushdecl_top_level): Likewise.
        (grokdeclarator): Clarify what is going on with setting
        DECL_EXTERNAL on function types, a little.
        (c_write_global_declarations): Don't do anything if
        -fsyntax-only or errors have been encountered.

testsuite:
        * gcc.dg/noncompile/init-4.c: Remove bogus dg-error marker.

===================================================================
Index: c-decl.c
--- c-decl.c	8 Jul 2004 19:50:17 -0000	1.531
+++ c-decl.c	9 Jul 2004 21:17:53 -0000
@@ -622,6 +622,16 @@ push_scope (void)
     }
 }
 
+/* Set the TYPE_CONTEXT of all of TYPE's variants to CONTEXT.  */
+
+static void
+set_type_context (tree type, tree context)
+{
+  for (type = TYPE_MAIN_VARIANT (type); type;
+       type = TYPE_NEXT_VARIANT (type))
+    TYPE_CONTEXT (type) = context;
+}
+
 /* Exit a scope.  Restore the state of the identifier-decl mappings
    that were in effect when this scope was entered.  Return a BLOCK
    node containing all the DECLs in this scope that are of interest
@@ -711,7 +721,7 @@ pop_scope (void)
 	case ENUMERAL_TYPE:
 	case UNION_TYPE:
 	case RECORD_TYPE:
-	  TYPE_CONTEXT (p) = context;
+	  set_type_context (p, context);
 
 	  /* Types may not have tag-names, in which case the type
 	     appears in the bindings list with b->id NULL.  */
@@ -767,7 +777,11 @@ pop_scope (void)
 	     This makes same_translation_unit_p work, and causes
 	     static declarations to be given disambiguating suffixes.  */
 	  if (scope == file_scope && num_in_fnames > 1)
-	    DECL_CONTEXT (p) = context;
+	    {
+	      DECL_CONTEXT (p) = context;
+	      if (TREE_CODE (p) == TYPE_DECL)
+		set_type_context (TREE_TYPE (p), context);
+	    }
 
 	  /* Fall through.  */
 	  /* Parameters go in DECL_ARGUMENTS, not BLOCK_VARS, and have
@@ -865,7 +879,6 @@ pop_file_scope (void)
   /* Pop off the file scope and close this translation unit.  */
   pop_scope ();
   file_scope = 0;
-  cpp_undef_all (parse_in);
   cgraph_finalize_compilation_unit ();
 }
 
@@ -1215,7 +1228,8 @@ diagnose_mismatched_decls (tree newdecl,
 	      && !(DECL_DECLARED_INLINE_P (olddecl)
 		   && DECL_EXTERNAL (olddecl)
 		   && !(DECL_DECLARED_INLINE_P (newdecl)
-			&& DECL_EXTERNAL (newdecl))))
+			&& DECL_EXTERNAL (newdecl)
+	    		&& same_translation_unit_p (olddecl, newdecl))))
 	    {
 	      error ("%Jredefinition of '%D'", newdecl, newdecl);
 	      locate_old_decl (olddecl, error);
@@ -1385,8 +1399,11 @@ diagnose_mismatched_decls (tree newdecl,
 
       /* Inline declaration after use or definition.
 	 ??? Should we still warn about this now we have unit-at-a-time
-	 mode and can get it right?  */
-      if (DECL_DECLARED_INLINE_P (newdecl) && !DECL_DECLARED_INLINE_P (olddecl))
+	 mode and can get it right?
+	 Definitely don't complain if the decls are in different translation
+	 units.  */
+      if (DECL_DECLARED_INLINE_P (newdecl) && !DECL_DECLARED_INLINE_P (olddecl)
+	  && same_translation_unit_p (olddecl, newdecl))
 	{
 	  if (TREE_USED (olddecl))
 	    {
@@ -1669,14 +1686,16 @@ merge_decls (tree newdecl, tree olddecl,
     }
 
   /* Copy most of the decl-specific fields of NEWDECL into OLDDECL.
-     But preserve OLDDECL's DECL_UID.  */
+     But preserve OLDDECL's DECL_UID and DECL_CONTEXT.  */
   {
     unsigned olddecl_uid = DECL_UID (olddecl);
+    tree olddecl_context = DECL_CONTEXT (olddecl);
 
     memcpy ((char *) olddecl + sizeof (struct tree_common),
 	    (char *) newdecl + sizeof (struct tree_common),
 	    sizeof (struct tree_decl) - sizeof (struct tree_common));
     DECL_UID (olddecl) = olddecl_uid;
+    DECL_CONTEXT (olddecl) = olddecl_context;
   }
 
   /* If OLDDECL had its DECL_RTL instantiated, re-invoke make_decl_rtl
@@ -1897,14 +1916,13 @@ pushdecl (tree x)
 	 they are in different translation units.  In any case,
 	 the static does not go in the externals scope.  */
       if (b
-	  && (DECL_EXTERNAL (x) || TREE_PUBLIC (x)
-	      || same_translation_unit_p (x, b->decl))
+	  && (TREE_PUBLIC (x) || same_translation_unit_p (x, b->decl))
 	  && duplicate_decls (x, b->decl))
 	{
 	  bind (name, b->decl, scope, /*invisible=*/false, /*nested=*/true);
 	  return b->decl;
 	}
-      else if (DECL_EXTERNAL (x) || TREE_PUBLIC (x))
+      else if (TREE_PUBLIC (x))
 	{
 	  bind (name, x, external_scope, /*invisible=*/true, /*nested=*/false);
 	  nested = true;
@@ -1991,7 +2009,7 @@ pushdecl_top_level (tree x)
   if (I_SYMBOL_BINDING (name))
     abort ();
 
-  if (DECL_EXTERNAL (x) || TREE_PUBLIC (x))
+  if (TREE_PUBLIC (x))
     {
       bind (name, x, external_scope, /*invisible=*/true, /*nested=*/false);
       nested = true;
@@ -4459,14 +4477,6 @@ grokdeclarator (tree declarator, tree de
       }
     else if (TREE_CODE (type) == FUNCTION_TYPE)
       {
-	/* Every function declaration is "external"
-	   except for those which are inside a function body
-	   in which `auto' is used.
-	   That is a case not specified by ANSI C,
-	   and we use it for forward declarations for nested functions.  */
-	int extern_ref = (!(specbits & (1 << (int) RID_AUTO))
-			  || current_scope == file_scope);
-
 	if (specbits & (1 << (int) RID_AUTO)
 	    && (pedantic || current_scope == file_scope))
 	  pedwarn ("invalid storage class for function `%s'", name);
@@ -4497,8 +4507,16 @@ grokdeclarator (tree declarator, tree de
 	    && !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (decl))))
 	  warning ("`noreturn' function returns non-void value");
 
-	if (extern_ref)
+	/* Every function declaration is an external reference
+	   (DECL_EXTERNAL) except for those which are not at file
+	   scope and are explicitly declared "auto".  This is
+	   forbidden by standard C (C99 6.7.1p5) and is interpreted by
+	   GCC to signify a forward declaration of a nested function.  */
+	if ((specbits & (1 << RID_AUTO)) && current_scope != file_scope)
+	  DECL_EXTERNAL (decl) = 0;
+	else
 	  DECL_EXTERNAL (decl) = 1;
+	   
 	/* Record absence of global scope for `static' or `auto'.  */
 	TREE_PUBLIC (decl)
 	  = !(specbits & ((1 << (int) RID_STATIC) | (1 << (int) RID_AUTO)));
@@ -6630,6 +6648,11 @@ c_write_global_declarations (void)
   if (pch_file)
     return;
 
+  /* Don't waste time on further processing if -fsyntax-only or we've
+     encountered errors.  */
+  if (flag_syntax_only || errorcount || sorrycount || cpp_errors (parse_in))
+    return;
+
   /* Close the external scope.  */
   ext_block = pop_scope ();
   external_scope = 0;
===================================================================
Index: c-opts.c
--- c-opts.c	30 Jun 2004 18:05:04 -0000	1.119
+++ c-opts.c	9 Jul 2004 21:17:53 -0000
@@ -943,6 +943,11 @@ c_common_post_options (const char **pfil
       flag_inline_functions = 0;
     }
 
+  /* If we are given more than one input file, we must use
+     unit-at-a-time mode.  */
+  if (num_in_fnames > 1)
+    flag_unit_at_a_time = 1;
+
   /* Default to ObjC sjlj exception handling if NeXT runtime.  */
   if (flag_objc_sjlj_exceptions < 0)
     flag_objc_sjlj_exceptions = flag_next_runtime;
@@ -1061,22 +1066,37 @@ c_common_init (void)
 void
 c_common_parse_file (int set_yydebug)
 {
+  unsigned int i;
+
+  /* Enable parser debugging, if requested and we can.  If requested
+     and we can't, notify the user.  */
 #if YYDEBUG != 0
   yydebug = set_yydebug;
 #else
   if (set_yydebug)
-    warning ("YYDEBUG not defined");
+    warning ("YYDEBUG was not defined at build time, -dy ignored");
 #endif
 
-  if (num_in_fnames > 1)
-    fatal_error ("sorry, inter-module analysis temporarily out of commission");
+  i = 0;
+  for (;;)
+    {
+      finish_options ();
+      pch_init ();
+      push_file_scope ();
+      c_parse_file ();
+      finish_file ();
+      pop_file_scope ();
 
-  finish_options ();
-  pch_init ();
-  push_file_scope ();
-  c_parse_file ();
-  finish_file ();
-  pop_file_scope ();
+      if (++i >= num_in_fnames)
+	break;
+      cpp_undef_all (parse_in);
+      this_input_filename
+	= cpp_read_main_file (parse_in, in_fnames[i]);
+      /* If an input file is missing, abandon further compilation.
+         cpplib has issued a diagnostic.  */
+      if (!this_input_filename)
+	break;
+    }
 }
 
 /* Common finish hook for the C, ObjC and C++ front ends.  */
===================================================================
Index: testsuite/gcc.dg/noncompile/init-4.c
--- testsuite/gcc.dg/noncompile/init-4.c	7 Apr 2003 11:55:27 -0000	1.1
+++ testsuite/gcc.dg/noncompile/init-4.c	9 Jul 2004 21:17:55 -0000
@@ -1,3 +1,2 @@
 struct a { char *b; } c[D] /* { dg-error "undeclared" } */
-  =                        /* { dg-error "storage size" } */
-    { { "" } } ;  /* { dg-warning "braces around scalar initializer|near" } */
+  = { { "" } } ;  /* { dg-warning "braces around scalar initializer|near" } */

Re: IMA: re-enable

[Per Bothner]

Zack Weinberg wrote:

> File/line reports in diagnostics for the second and successive
> translation units are completely bogus.  I do not think this is worth
> bothering to fix until Per is done with his fileline project; it may
> magically go away in the course of that, and even if it doesn't, it
> will be easier to fix then.

Easy enough to verify:  configure with --enable-mapped-location
--enable-languages=c,c++.
-- 
	--Per Bothner
per@bothner.com   http://per.bothner.com/