fix collected c++ gc regressions

[Richard Henderson <rth at redhat dot com>]

Fixes

-FAIL: g++.dg/debug/debug2.C (test for excess errors)
-FAIL: g++.old-deja/g++.jason/template37.C (test for excess errors)
-FAIL: g++.old-deja/g++.mike/p1989.C (test for excess errors)
-FAIL: g++.old-deja/g++.pt/explicit74.C (test for excess errors)
-FAIL: g++.old-deja/g++.pt/ttp34.C (test for excess errors)

There's one more segmentation fault in the logs, 

FAIL: g++.dg/init/new6.C (test for excess errors)

which I have not yet investigated, but with 20 hour gcac build 
times this has taken long enough already.  At least this is 
monotonic change in the right direction.


r~



gc/
        * c-decl.c (c_expand_body_1): Push and pop function context here.
        * tree-optimize.c (tree_rest_of_compilation): ... not here.  Take
        nested argument instead of computing nesting ourselves.

gcc/cp/
        * decl.c (finish_function): Clear current_function_decl.
        * decl2.c (mark_used): Don't push/pop gc context.
        * optimize.c (optimize_function): Likewise.
        * tree.c (cp_cannot_inline_tree_fn): Likewise.
        * pt.c (instantiate_decl): Inc/dec function_depth instead.
        * semantics.c (expand_body): Update for tree_rest_of_compilation
        nested argument.

Index: gcc/c-decl.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/c-decl.c,v
retrieving revision 1.443
diff -u -p -r1.443 c-decl.c
--- gcc/c-decl.c	6 Sep 2003 13:33:53 -0000	1.443
+++ gcc/c-decl.c	8 Sep 2003 15:47:39 -0000
@@ -6181,9 +6181,16 @@ c_expand_body_1 (tree fndecl, int nested
       /* Make sure that we will evaluate variable-sized types involved
 	 in our function's type.  */
       expand_pending_sizes (DECL_LANG_SPECIFIC (fndecl)->pending_sizes);
+
+      /* Squirrel away our current state.  */
+      push_function_context ();
     }
 
-  tree_rest_of_compilation (fndecl);
+  tree_rest_of_compilation (fndecl, nested_p);
+
+  if (nested_p)
+    /* Return to the enclosing function.  */
+    pop_function_context ();
 
   if (DECL_STATIC_CONSTRUCTOR (fndecl))
     {
Index: gcc/toplev.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/toplev.h,v
retrieving revision 1.113
diff -u -p -r1.113 toplev.h
--- gcc/toplev.h	29 Aug 2003 23:21:11 -0000	1.113
+++ gcc/toplev.h	8 Sep 2003 15:47:39 -0000
@@ -66,7 +66,7 @@ extern void inform (const char *, ...) A
 extern void rest_of_decl_compilation (tree, const char *, int, int);
 extern void rest_of_type_compilation (tree, int);
 extern void rest_of_compilation (tree);
-extern void tree_rest_of_compilation (tree);
+extern void tree_rest_of_compilation (tree, bool);
 
 extern void announce_function (tree);
 
Index: gcc/tree-optimize.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/tree-optimize.c,v
retrieving revision 2.1
diff -u -p -r2.1 tree-optimize.c
--- gcc/tree-optimize.c	29 Aug 2003 23:21:11 -0000	2.1
+++ gcc/tree-optimize.c	8 Sep 2003 15:47:39 -0000
@@ -93,21 +93,13 @@ clear_decl_rtl (tree *tp, int *walk_subt
    compilation for FNDECL.  */
 
 void
-tree_rest_of_compilation (tree fndecl)
+tree_rest_of_compilation (tree fndecl, bool nested_p)
 {
-  static int nesting = -1;
-
   timevar_push (TV_EXPAND);
 
-  ++nesting;
-
   if (flag_unit_at_a_time && !cgraph_global_info_ready)
     abort ();
 
-  if (nesting > 0)
-    /* Squirrel away our current state.  */
-    push_function_context ();
-
   /* Initialize the RTL code for the function.  */
   current_function_decl = fndecl;
   input_location = DECL_SOURCE_LOCATION (fndecl);
@@ -162,7 +154,7 @@ tree_rest_of_compilation (tree fndecl)
 
   /* If this is a nested function, protect the local variables in the stack
      above us from being collected while we're compiling this function.  */
-  if (nesting > 0)
+  if (nested_p)
     ggc_push_context ();
 
   /* There's no need to defer outputting this function any more; we
@@ -173,7 +165,7 @@ tree_rest_of_compilation (tree fndecl)
   rest_of_compilation (fndecl);
 
   /* Undo the GC context switch.  */
-  if (nesting > 0)
+  if (nested_p)
     ggc_pop_context ();
 
   /* If requested, warn about function definitions where the function will
@@ -227,7 +219,7 @@ tree_rest_of_compilation (tree fndecl)
 				clear_decl_rtl,
 				fndecl);
 
-  if (DECL_SAVED_INSNS (fndecl) == 0 && ! nesting && ! flag_inline_trees)
+  if (DECL_SAVED_INSNS (fndecl) == 0 && !nested_p && !flag_inline_trees)
     {
       /* Stop pointing to the local nodes about to be freed.
 	 But DECL_INITIAL must remain nonzero so we know this
@@ -239,12 +231,6 @@ tree_rest_of_compilation (tree fndecl)
 
       DECL_ARGUMENTS (fndecl) = 0;
     }
-
-  if (nesting > 0)
-    /* Return to the enclosing function.  */
-    pop_function_context ();
-
-  --nesting;
 
   timevar_pop (TV_EXPAND);
 }
Index: gcc/cp/decl.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/cp/decl.c,v
retrieving revision 1.1124
diff -u -p -r1.1124 decl.c
--- gcc/cp/decl.c	7 Sep 2003 18:52:52 -0000	1.1124
+++ gcc/cp/decl.c	8 Sep 2003 15:47:50 -0000
@@ -14104,6 +14104,7 @@ finish_function (int flags)
   /* We're leaving the context of this function, so zap cfun.  It's still in
      DECL_SAVED_INSNS, and we'll restore it in tree_rest_of_compilation.  */
   cfun = NULL;
+  current_function_decl = NULL;
 
   /* If this is an in-class inline definition, we may have to pop the
      bindings for the template parameters that we added in
Index: gcc/cp/decl2.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/cp/decl2.c,v
retrieving revision 1.668
diff -u -p -r1.668 decl2.c
--- gcc/cp/decl2.c	7 Sep 2003 11:15:46 -0000	1.668
+++ gcc/cp/decl2.c	8 Sep 2003 15:47:54 -0000
@@ -4232,10 +4232,7 @@ mark_used (tree decl)
 		  information.  */
 	       || cp_function_chain->can_throw);
 
-      /* Our caller is likely to have lots of data on the stack.  */
-      ggc_push_context ();
       instantiate_decl (decl, defer);
-      ggc_pop_context ();
     }
 }
 
Index: gcc/cp/optimize.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/cp/optimize.c,v
retrieving revision 1.96
diff -u -p -r1.96 optimize.c
--- gcc/cp/optimize.c	3 Sep 2003 21:38:26 -0000	1.96
+++ gcc/cp/optimize.c	8 Sep 2003 15:47:54 -0000
@@ -56,31 +56,7 @@ optimize_function (tree fn)
          and (d) TARGET_ASM_OUTPUT_MI_THUNK is there to DTRT anyway.  */
       && !DECL_THUNK_P (fn))
     {
-      /* ??? Work around GC problem.  Call stack is
-
-	 -> instantiate_decl
-	 -> expand_or_defer_fn
-	 -> maybe_clone_body
-	 -> expand_body
-	 -> tree_rest_of_compilation
-
-	 which of course collects.  This used to be protected by the
-	 "regular" nested call ggc_push_context that now lives in 
-	 tree_rest_of_compilation.
-
-	 Two good fixes:
-	 (1) Do inlining in tree_rest_of_compilation.  This is good
-	     in that this common optimization happens in common code.
-	 (2) Don't nest compilation of functions.  Instead queue the
-	     new function to cgraph, and let it get picked up in the
-	     next round of "emit everything that needs emitting".
-
-	 For the nonce, just protect things here.  */
-
-      ggc_push_context ();
       optimize_inline_calls (fn);
-      ggc_pop_context ();
-
       dump_function (TDI_inlined, fn);
     }
   
Index: gcc/cp/pt.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/cp/pt.c,v
retrieving revision 1.775
diff -u -p -r1.775 pt.c
--- gcc/cp/pt.c	5 Sep 2003 18:04:15 -0000	1.775
+++ gcc/cp/pt.c	8 Sep 2003 15:48:03 -0000
@@ -10730,10 +10730,14 @@ instantiate_decl (tree d, int defer_ok)
 
   timevar_push (TV_PARSE);
 
-  /* We may be in the middle of deferred access check.  Disable
-     it now.  */
+  /* We may be in the middle of deferred access check.  Disable it now.  */
   push_deferring_access_checks (dk_no_deferred);
 
+  /* Our caller does not expect collection to happen, which it might if
+     we decide to compile the function to rtl now.  Arrange for a new
+     gc context to be created if so.  */
+  function_depth++;
+
   /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
      for the instantiation.  */
   td = template_for_substitution (d);
@@ -10978,6 +10982,7 @@ out:
   input_location = saved_loc;
   pop_deferring_access_checks ();
   pop_tinst_level ();
+  function_depth--;
 
   timevar_pop (TV_PARSE);
 
Index: gcc/cp/semantics.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/cp/semantics.c,v
retrieving revision 1.356
diff -u -p -r1.356 semantics.c
--- gcc/cp/semantics.c	5 Sep 2003 08:38:42 -0000	1.356
+++ gcc/cp/semantics.c	8 Sep 2003 15:48:05 -0000
@@ -2868,7 +2868,7 @@ expand_body (tree fn)
   optimize_function (fn);
   timevar_pop (TV_INTEGRATION);
 
-  tree_rest_of_compilation (fn);
+  tree_rest_of_compilation (fn, function_depth > 1);
 
   current_function_decl = saved_function;
   input_location = saved_loc;
Index: gcc/cp/tree.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/cp/tree.c,v
retrieving revision 1.345
diff -u -p -r1.345 tree.c
--- gcc/cp/tree.c	5 Sep 2003 08:24:21 -0000	1.345
+++ gcc/cp/tree.c	8 Sep 2003 15:48:06 -0000
@@ -2026,14 +2026,7 @@ cp_cannot_inline_tree_fn (tree* fnp)
 			(template_for_substitution (fn))))
 	return 1;
 
-      /* Our caller does not expect us to call ggc_collect, but
-	 instantiate_decl can call rest_of_compilation so we must
-	 protect our caller.  */
-      ggc_push_context();
-      
       fn = *fnp = instantiate_decl (fn, /*defer_ok=*/0);
-
-      ggc_pop_context();
 
       if (TI_PENDING_TEMPLATE_FLAG (DECL_TEMPLATE_INFO (fn)))
 	return 1;