Fix ICEs related to VM types in C 1/2 [PR70418, PR107557, PR108423]

Size expressions were sometimes lost and not gimplified correctly, leading to
ICEs and incorrect evaluation order.  Fix this by 1) not recursing into
pointers when gimplifying parameters in the middle-end (the code is merged with
gimplify_type_sizes), which is incorrect because it might access variables
declared later for incomplete structs, and 2) tracking size expressions for
struct/union members correctly, 3) emitting code to evaluate size expressions
for missing cases (nested functions, empty declarations, and structs/unions).

	PR c/70418
	PR c/106465
	PR c/107557
	PR c/108423

	gcc/c/
	* c-decl.cc (start_decl): Make sure size expression are
	evaluated only in correct context.
	(grokdeclarator): Size expression in fields may need a bind
	expression, make sure DECL_EXPR is always created.
	(grokfield, declspecs_add_type): Pass along size expressions.
	(finish_struct): Remove unneeded DECL_EXPR.
	(start_function): Evaluate size expressions for nested functions.
	* c-parser.cc (c_parser_struct_declarations,
	c_parser_struct_or_union_specifier): Pass along size expressions.
	(c_parser_declaration_or_fndef): Evaluate size expression.
	(c_parser_objc_at_property_declaration,
	c_parser_objc_class_instance_variables): Adapt.
	* c-tree.h (grokfield): Adapt declaration.

	gcc/testsuite/
	* gcc.dg/nested-vla-1.c: New test.
	* gcc.dg/nested-vla-2.c: New test.
	* gcc.dg/nested-vla-3.c: New test.
	* gcc.dg/pr70418.c: New test.
	* gcc.dg/pr106465.c: New test.
	* gcc.dg/pr107557-1.c: New test.
	* gcc.dg/pr107557-2.c: New test.
	* gcc.dg/pr108423-1.c: New test.
	* gcc.dg/pr108423-2.c: New test.
	* gcc.dg/pr108423-3.c: New test.
	* gcc.dg/pr108423-4.c: New test.
	* gcc.dg/pr108423-5.c: New test.
	* gcc.dg/pr108423-6.c: New test.
	* gcc.dg/typename-vla-2.c: New test.
	* gcc.dg/typename-vla-3.c: New test.
	* gcc.dg/typename-vla-4.c: New test.
	* gcc.misc-tests/gcov-pr85350.c: Adapt.

3 files changed, 36 insertions, 27 deletions

diff --git a/gcc/c/c-decl.cc b/gcc/c/c-decl.cc
index 94ce760..494d3cf 100644
--- a/gcc/c/c-decl.cc
+++ b/gcc/c/c-decl.cc
@@ -5364,7 +5364,8 @@ start_decl (struct c_declarator *declarator, struct c_declspecs *declspecs,
     if (lastdecl != error_mark_node)
       *lastloc = DECL_SOURCE_LOCATION (lastdecl);
 
-  if (expr)
+  /* Make sure the size expression is evaluated at this point.  */
+  if (expr && !current_scope->parm_flag)
     add_stmt (fold_convert (void_type_node, expr));
 
   if (TREE_CODE (decl) != FUNCTION_DECL && MAIN_NAME_P (DECL_NAME (decl))
@@ -7498,7 +7499,8 @@ grokdeclarator (const struct c_declarator *declarator,
 		&& c_type_variably_modified_p (type))
 	      {
 		tree bind = NULL_TREE;
-		if (decl_context == TYPENAME || decl_context == PARM)
+		if (decl_context == TYPENAME || decl_context == PARM
+		    || decl_context == FIELD)
 		  {
 		    bind = build3 (BIND_EXPR, void_type_node, NULL_TREE,
 				   NULL_TREE, NULL_TREE);
@@ -7507,10 +7509,11 @@ grokdeclarator (const struct c_declarator *declarator,
 		    push_scope ();
 		  }
 		tree decl = build_decl (loc, TYPE_DECL, NULL_TREE, type);
-		DECL_ARTIFICIAL (decl) = 1;
 		pushdecl (decl);
-		finish_decl (decl, loc, NULL_TREE, NULL_TREE, NULL_TREE);
+		DECL_ARTIFICIAL (decl) = 1;
+		add_stmt (build_stmt (DECL_SOURCE_LOCATION (decl), DECL_EXPR, decl));
 		TYPE_NAME (type) = decl;
+
 		if (bind)
 		  {
 		    pop_scope ();
@@ -8709,7 +8712,7 @@ start_struct (location_t loc, enum tree_code code, tree name,
 tree
 grokfield (location_t loc,
 	   struct c_declarator *declarator, struct c_declspecs *declspecs,
-	   tree width, tree *decl_attrs)
+	   tree width, tree *decl_attrs, tree *expr)
 {
   tree value;
 
@@ -8766,7 +8769,7 @@ grokfield (location_t loc,
     }
 
   value = grokdeclarator (declarator, declspecs, FIELD, false,
-			  width ? &width : NULL, decl_attrs, NULL, NULL,
+			  width ? &width : NULL, decl_attrs, expr, NULL,
 			  DEPRECATED_NORMAL);
 
   finish_decl (value, loc, NULL_TREE, NULL_TREE, NULL_TREE);
@@ -9424,13 +9427,6 @@ finish_struct (location_t loc, tree t, tree fieldlist, tree attributes,
 
   finish_incomplete_vars (incomplete_vars, toplevel);
 
-  /* If we're inside a function proper, i.e. not file-scope and not still
-     parsing parameters, then arrange for the size of a variable sized type
-     to be bound now.  */
-  if (building_stmt_list_p () && c_type_variably_modified_p(t))
-    add_stmt (build_stmt (loc,
-			  DECL_EXPR, build_decl (loc, TYPE_DECL, NULL, t)));
-
   if (warn_cxx_compat)
     warn_cxx_compat_finish_struct (fieldlist, TREE_CODE (t), loc);
 
@@ -10056,6 +10052,7 @@ start_function (struct c_declspecs *declspecs, struct c_declarator *declarator,
   tree restype, resdecl;
   location_t loc;
   location_t result_loc;
+  tree expr = NULL;
 
   current_function_returns_value = 0;  /* Assume, until we see it does.  */
   current_function_returns_null = 0;
@@ -10067,7 +10064,7 @@ start_function (struct c_declspecs *declspecs, struct c_declarator *declarator,
   in_statement = 0;
 
   decl1 = grokdeclarator (declarator, declspecs, FUNCDEF, true, NULL,
-			  &attributes, NULL, NULL, DEPRECATED_NORMAL);
+			  &attributes, &expr, NULL, DEPRECATED_NORMAL);
   invoke_plugin_callbacks (PLUGIN_START_PARSE_FUNCTION, decl1);
 
   /* If the declarator is not suitable for a function definition,
@@ -10076,6 +10073,11 @@ start_function (struct c_declspecs *declspecs, struct c_declarator *declarator,
       || TREE_CODE (decl1) != FUNCTION_DECL)
     return false;
 
+  /* Nested functions may have variably modified (return) type.
+     Make sure the size expression is evaluated at this point.  */
+  if (expr && !current_scope->parm_flag)
+    add_stmt (fold_convert (void_type_node, expr));
+
   loc = DECL_SOURCE_LOCATION (decl1);
 
   /* A nested function is not global.  */
@@ -12284,10 +12286,13 @@ declspecs_add_type (location_t loc, struct c_declspecs *specs,
     }
   else
     {
-      if (TREE_CODE (type) != ERROR_MARK && spec.kind == ctsk_typeof)
+      if (TREE_CODE (type) != ERROR_MARK)
 	{
-	  specs->typedef_p = true;
-	  specs->locations[cdw_typedef] = loc;
+	  if (spec.kind == ctsk_typeof)
+	    {
+	      specs->typedef_p = true;
+	      specs->locations[cdw_typedef] = loc;
+	    }
 	  if (spec.expr)
 	    {
 	      if (specs->expr)
diff --git a/gcc/c/c-parser.cc b/gcc/c/c-parser.cc
index 11ac865..0ec7534 100644
--- a/gcc/c/c-parser.cc
+++ b/gcc/c/c-parser.cc
@@ -1541,7 +1541,7 @@ static void c_parser_static_assert_declaration_no_semi (c_parser *);
 static void c_parser_static_assert_declaration (c_parser *);
 static struct c_typespec c_parser_enum_specifier (c_parser *);
 static struct c_typespec c_parser_struct_or_union_specifier (c_parser *);
-static tree c_parser_struct_declaration (c_parser *);
+static tree c_parser_struct_declaration (c_parser *, tree *);
 static struct c_typespec c_parser_typeof_specifier (c_parser *);
 static tree c_parser_alignas_specifier (c_parser *);
 static struct c_declarator *c_parser_direct_declarator (c_parser *, bool,
@@ -2263,6 +2263,9 @@ c_parser_declaration_or_fndef (c_parser *parser, bool fndef_ok,
 	  if (!handled_assume)
 	    pedwarn (here, 0, "empty declaration");
 	}
+      /* We still have to evaluate size expressions.  */
+      if (specs->expr)
+	add_stmt (fold_convert (void_type_node, specs->expr));
       c_parser_consume_token (parser);
       if (oacc_routine_data)
 	c_finish_oacc_routine (oacc_routine_data, NULL_TREE, false);
@@ -3782,6 +3785,7 @@ c_parser_struct_or_union_specifier (c_parser *parser)
 	 so we'll be minimizing the number of node traversals required
 	 by chainon.  */
       tree contents;
+      tree expr = NULL;
       timevar_push (TV_PARSE_STRUCT);
       contents = NULL_TREE;
       c_parser_consume_token (parser);
@@ -3843,7 +3847,7 @@ c_parser_struct_or_union_specifier (c_parser *parser)
 	    }
 	  /* Parse some comma-separated declarations, but not the
 	     trailing semicolon if any.  */
-	  decls = c_parser_struct_declaration (parser);
+	  decls = c_parser_struct_declaration (parser, &expr);
 	  contents = chainon (decls, contents);
 	  /* If no semicolon follows, either we have a parse error or
 	     are at the end of the struct or union and should
@@ -3874,7 +3878,7 @@ c_parser_struct_or_union_specifier (c_parser *parser)
 					 chainon (attrs, postfix_attrs)),
 				struct_info);
       ret.kind = ctsk_tagdef;
-      ret.expr = NULL_TREE;
+      ret.expr = expr;
       ret.expr_const_operands = true;
       ret.has_enum_type_specifier = false;
       timevar_pop (TV_PARSE_STRUCT);
@@ -3936,7 +3940,7 @@ c_parser_struct_or_union_specifier (c_parser *parser)
    expressions will be diagnosed as non-constant.  */
 
 static tree
-c_parser_struct_declaration (c_parser *parser)
+c_parser_struct_declaration (c_parser *parser, tree *expr)
 {
   struct c_declspecs *specs;
   tree prefix_attrs;
@@ -3949,7 +3953,7 @@ c_parser_struct_declaration (c_parser *parser)
       tree decl;
       ext = disable_extension_diagnostics ();
       c_parser_consume_token (parser);
-      decl = c_parser_struct_declaration (parser);
+      decl = c_parser_struct_declaration (parser, expr);
       restore_extension_diagnostics (ext);
       return decl;
     }
@@ -3995,7 +3999,7 @@ c_parser_struct_declaration (c_parser *parser)
 
 	  ret = grokfield (c_parser_peek_token (parser)->location,
 			   build_id_declarator (NULL_TREE), specs,
-			   NULL_TREE, &attrs);
+			   NULL_TREE, &attrs, expr);
 	  if (ret)
 	    decl_attributes (&ret, attrs, 0);
 	}
@@ -4056,7 +4060,7 @@ c_parser_struct_declaration (c_parser *parser)
 	  if (c_parser_next_token_is_keyword (parser, RID_ATTRIBUTE))
 	    postfix_attrs = c_parser_gnu_attributes (parser);
 	  d = grokfield (c_parser_peek_token (parser)->location,
-			 declarator, specs, width, &all_prefix_attrs);
+			 declarator, specs, width, &all_prefix_attrs, expr);
 	  decl_attributes (&d, chainon (postfix_attrs,
 					all_prefix_attrs), 0);
 	  DECL_CHAIN (d) = decls;
@@ -11732,7 +11736,7 @@ c_parser_objc_class_instance_variables (c_parser *parser)
 	}
 
       /* Parse some comma-separated declarations.  */
-      decls = c_parser_struct_declaration (parser);
+      decls = c_parser_struct_declaration (parser, NULL);
       if (decls == NULL)
 	{
 	  /* There is a syntax error.  We want to skip the offending
@@ -12871,7 +12875,7 @@ c_parser_objc_at_property_declaration (c_parser *parser)
   /* 'properties' is the list of properties that we read.  Usually a
      single one, but maybe more (eg, in "@property int a, b, c;" there
      are three).  */
-  tree properties = c_parser_struct_declaration (parser);
+  tree properties = c_parser_struct_declaration (parser, NULL);
 
   if (properties == error_mark_node)
     c_parser_skip_until_found (parser, CPP_SEMICOLON, NULL);
diff --git a/gcc/c/c-tree.h b/gcc/c/c-tree.h
index e6b6fe9..7c5234e 100644
--- a/gcc/c/c-tree.h
+++ b/gcc/c/c-tree.h
@@ -656,7 +656,7 @@ extern tree c_simulate_record_decl (location_t, const char *,
 extern struct c_arg_info *build_arg_info (void);
 extern struct c_arg_info *get_parm_info (bool, tree);
 extern tree grokfield (location_t, struct c_declarator *,
-		       struct c_declspecs *, tree, tree *);
+		       struct c_declspecs *, tree, tree *, tree *);
 extern tree groktypename (struct c_type_name *, tree *, bool *);
 extern tree grokparm (const struct c_parm *, tree *);
 extern tree implicitly_declare (location_t, tree);