diff mbox series

PR c/30552 gcc crashes when compiling examples with GNU statement expressions in VLAs

Message ID 049888e7-2be4-3660-4a98-be709c16ea65@oracle.com
State New
Headers show
Series PR c/30552 gcc crashes when compiling examples with GNU statement expressions in VLAs | expand

Commit Message

dave.pagan@oracle.com March 13, 2018, 9:56 p.m. UTC 
This patch fixes ICE when statement expression used in old-style 
function declaration parameter list. See

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=30552

In c_parser_postfix_expression (), after seeing a left paren followed by 
a left curly brace, in addition to checking for existing statement list, 
also check to see if we're in the parameter scope an old-style function 
declaration. In either case, generate a "braced-group within expression 
allowed only inside a function" error.

Patch successfully bootstrapped and tested on x86_64-linux.

--Dave
/c
2018-03-13  David Pagan  <dave.pagan@oracle.com>

	PR c/30552
	* c-decl.c (old_style_parameter_scope): New function.
	* c-parser.c (c_parser_postfix_expression): Check for statement
	expressions in old-style function parameter list declarations.

/c-family
2018-03-13  David Pagan  <dave.pagan@oracle.com>

	PR c/30552
	* c-common.h (old_style_parameter_scope): New extern declaration.

/testsuite
2018-03-13  David Pagan  <dave.pagan@oracle.com>

	PR c/30552
	* gcc.dg/noncompile/pr30552-1.c: New test.
	* gcc.dg/noncompile/pr30552-2.c: New test.
	* gcc.dg/noncompile/pr30552-3.c: New test.
	* gcc.dg/noncompile/pr30552-4.c: New test.

Comments

Jeff Law March 14, 2018, 4:05 a.m. UTC | #1 
On 03/13/2018 03:56 PM, dave.pagan@oracle.com wrote:
> This patch fixes ICE when statement expression used in old-style
> function declaration parameter list. See
> 
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=30552
> 
> In c_parser_postfix_expression (), after seeing a left paren followed by
> a left curly brace, in addition to checking for existing statement list,
> also check to see if we're in the parameter scope an old-style function
> declaration. In either case, generate a "braced-group within expression
> allowed only inside a function" error.
> 
> Patch successfully bootstrapped and tested on x86_64-linux.
Just a note.  We're in regression fixes only (stage4) of our development
cycle.  I've put this (and other patches) into the queue of things to
review once stage1 re-opens.

jeff
Jeff Law May 2, 2018, 5:23 p.m. UTC | #2 
On 03/13/2018 03:56 PM, dave.pagan@oracle.com wrote:
> This patch fixes ICE when statement expression used in old-style
> function declaration parameter list. See
> 
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=30552
> 
> In c_parser_postfix_expression (), after seeing a left paren followed by
> a left curly brace, in addition to checking for existing statement list,
> also check to see if we're in the parameter scope an old-style function
> declaration. In either case, generate a "braced-group within expression
> allowed only inside a function" error.
> 
> Patch successfully bootstrapped and tested on x86_64-linux.
I moved the declaration from c-common.h into c-parser.h which seems to
be a better location and fixed a couple of whitespace nits.

Installed on the trunk.

Thanks,
Jeff
diff mbox series

Patch

Index: c/c-decl.c
===================================================================
--- c/c-decl.c	(revision 258257)
+++ c/c-decl.c	(working copy)
@@ -952,6 +952,17 @@  global_bindings_p (void)
   return current_scope == file_scope;
 }
 
+/* Return true if we're declaring parameters in an old-style function
+   declaration.  */
+
+bool
+old_style_parameter_scope (void)
+{
+  /* If processing parameters and there is no function statement list, we
+   * have an old-style function declaration.  */
+  return (current_scope->parm_flag && !DECL_SAVED_TREE(current_function_decl));
+}
+
 void
 keep_next_level (void)
 {
Index: c/c-parser.c
===================================================================
--- c/c-parser.c	(revision 258257)
+++ c/c-parser.c	(working copy)
@@ -7929,7 +7929,10 @@  c_parser_postfix_expression (c_parser *parser)
 	  c_parser_consume_token (parser);
 	  brace_loc = c_parser_peek_token (parser)->location;
 	  c_parser_consume_token (parser);
-	  if (!building_stmt_list_p ())
+	  /* If we've not yet started the current function's statement list, 
+	     or we're in the parameter scope of an old-style function
+	     declaration, statement expressions are not allowed.  */
+	  if (!building_stmt_list_p () || old_style_parameter_scope ())
 	    {
 	      error_at (loc, "braced-group within expression allowed "
 			"only inside a function");
Index: c-family/c-common.h
===================================================================
--- c-family/c-common.h	(revision 258257)
+++ c-family/c-common.h	(working copy)
@@ -581,6 +581,7 @@  extern tree push_stmt_list (void);
 extern tree pop_stmt_list (tree);
 extern tree add_stmt (tree);
 extern void push_cleanup (tree, tree, bool);
+extern bool old_style_parameter_scope (void);
 
 extern tree build_modify_expr (location_t, tree, tree, enum tree_code,
 			       location_t, tree, tree);
Index: testsuite/gcc.dg/noncompile/pr30552-1.c
===================================================================
--- testsuite/gcc.dg/noncompile/pr30552-1.c	(revision 0)
+++ testsuite/gcc.dg/noncompile/pr30552-1.c	(working copy)
@@ -0,0 +1,17 @@ 
+/* PR c/30552 */
+
+/* Statement expression as formal array argument size in nested old-style 
+   function declaration should generate user error, not internal compiler 
+   error.  */
+
+/* { dg-do compile } */
+/* { dg-options "" } */
+
+int main()
+{
+  void fun(int a) /* { dg-error "old-style parameter declarations in prototyped function definition" } */
+    int a[({void h(){}2;})]; /* { dg-error "braced-group within expression allowed only inside a function" } */
+  {
+  }
+  return 0;
+}
Index: testsuite/gcc.dg/noncompile/pr30552-2.c
===================================================================
--- testsuite/gcc.dg/noncompile/pr30552-2.c	(revision 0)
+++ testsuite/gcc.dg/noncompile/pr30552-2.c	(working copy)
@@ -0,0 +1,17 @@ 
+/* PR c/30552 */
+
+/* Another example of a statement expression as formal array argument size in
+ * nested old-style function declaration should generate user error, not 
+ * internal compiler error.  */
+
+/* { dg-do compile } */
+/* { dg-options "" } */
+
+int main()
+{
+  void fun(a)
+    int a[({int b=2; b;})]; /* { dg-error "braced-group within expression allowed only inside a function" } */
+  {
+  }
+  return 0;
+}
Index: testsuite/gcc.dg/noncompile/pr30552-3.c
===================================================================
--- testsuite/gcc.dg/noncompile/pr30552-3.c	(revision 0)
+++ testsuite/gcc.dg/noncompile/pr30552-3.c	(working copy)
@@ -0,0 +1,15 @@ 
+/* PR c/30552 */
+
+/* Related example where statement expression used as old-style formal array 
+ * argument size in an invalid nested function declaration should generate 
+ * user error, not internal compiler error. */
+
+/* { dg-do compile } */
+/* { dg-options "" } */
+
+int main()
+{
+  int g()
+    int a[( {int b} )]; /* { dg-error "braced-group within expression allowed only inside a function|declaration for parameter" } */
+  return 0; /* { dg-error "expected declaration specifiers before" } */
+} /* { dg-error "expected declaration specifiers before|end of input|expected declaration or statement at end of input" } */
Index: testsuite/gcc.dg/noncompile/pr30552-4.c
===================================================================
--- testsuite/gcc.dg/noncompile/pr30552-4.c	(revision 0)
+++ testsuite/gcc.dg/noncompile/pr30552-4.c	(working copy)
@@ -0,0 +1,15 @@ 
+/* PR c/30552 */
+
+/* Statement expression as formal array argument size in nested function
+ * prototype scope is valid.  */
+
+/* { dg-do compile } */
+/* { dg-options "" } */
+
+int main()
+{
+  void fun(int a[({void h(){}10;})])
+  {
+  }
+  return 0;
+}