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.

1 files changed, 13 insertions, 9 deletions

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);