diff mbox series

PR c++/39751: ICE-on-invalid parsing regression.

Message ID 002b01d82b6c$4adcdb40$e09691c0$@nextmovesoftware.com
State New
Headers
Series PR c++/39751: ICE-on-invalid parsing regression. |

Commit Message

Roger Sayle Feb. 26, 2022, 11:55 p.m. UTC 
  This is a fix for PR c++/39751 which is an ICE-on-invalid regression in
the C++ parser after encountering the end of file.  The one line change
is to check that the tokens cached in DECL_PENDING_INLINE_INFO haven't
been purged before processing them in cp_parser_late_parsing_for_member.

Alas in addition to the one line fix (and new test case), I've also
taken the opportunity to silence the -Wmissing-field-initializers
warnings compiling this source file, by replacing the " = { };" with
explicit calls to memset to initialize/reset structures.

This patch has been tested on x86_64-pc-linux-gnu with make bootstrap
and make -k check with no new (unexpected) failures.  Ok for mainline?


2022-02-26  Roger Sayle  <roger@nextmovesoftware.com>

gcc/cp/ChangeLog
	PR c++/39751
	* parser.cc (cp_parser_late_parsing_for_member): Confirm the token
	stream hasn't been purged before processing DECL_PENDING_INLINE.

	(cp_parser_handle_statement_omp_attributes): Silence compilation
	warnings using memset to initialize structure.
	(cp_parser_late_parsing_omp_declare_simd): Likewise.

gcc/testsuite/ChangeLog
	PR c++/39751
	* g++.dg/pr39751.C: New test case.


Thanks in advance,
Roger
--

Comments

Jason Merrill March 10, 2022, 5:01 a.m. UTC | #1 
On 2/26/22 19:55, Roger Sayle wrote:
> 
> This is a fix for PR c++/39751 which is an ICE-on-invalid regression in
> the C++ parser after encountering the end of file.  The one line change
> is to check that the tokens cached in DECL_PENDING_INLINE_INFO haven't
> been purged before processing them in cp_parser_late_parsing_for_member.
> 
> Alas in addition to the one line fix (and new test case), I've also
> taken the opportunity to silence the -Wmissing-field-initializers
> warnings compiling this source file, by replacing the " = { };" with
> explicit calls to memset to initialize/reset structures.
> 
> This patch has been tested on x86_64-pc-linux-gnu with make bootstrap
> and make -k check with no new (unexpected) failures.  Ok for mainline?
> 
> 
> 2022-02-26  Roger Sayle  <roger@nextmovesoftware.com>
> 
> gcc/cp/ChangeLog
> 	PR c++/39751
> 	* parser.cc (cp_parser_late_parsing_for_member): Confirm the token
> 	stream hasn't been purged before processing DECL_PENDING_INLINE.

This is OK.

> 	(cp_parser_handle_statement_omp_attributes): Silence compilation
> 	warnings using memset to initialize structure.
> 	(cp_parser_late_parsing_omp_declare_simd): Likewise.

These are not; I don't want to uglify the code to satisfy a broken 
warning.  The warning is documented to allow this pattern:

      Likewise, in C++ this option does not warn about the empty { }
      initializer, for example:

           struct s { int f, g, h; };
           s x = { };

So all the instances you changed indicate a bug in the warning that 
should be fixed rather than worked around.

Even if this were OK, it's completely unrelated to PR39751, so should 
have been a separate patch.

> +++ b/gcc/testsuite/g++.dg/pr39751.C

Should go in g++.dg/parse/

> +/* { dg-options "-O2" } */

Unneeded.

Jason
diff mbox series

Patch

diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc
index 03d99ab..585502b 100644
--- a/gcc/cp/parser.cc
+++ b/gcc/cp/parser.cc
@@ -11935,7 +11935,8 @@  cp_parser_handle_statement_omp_attributes (cp_parser *parser, tree attrs)
 	    if (flag_openmp || dir->simd)
 	      tokens += (last - first) + 1;
 	  }
-	cp_omp_attribute_data v = {};
+	cp_omp_attribute_data v;
+	memset (&v, 0, sizeof (v));
 	vec.safe_push (v);
 	*pa = TREE_CHAIN (*pa);
       }
@@ -12021,7 +12022,8 @@  cp_parser_handle_statement_omp_attributes (cp_parser *parser, tree attrs)
 	continue;
       cp_token *first = v->tokens->first;
       cp_token *last = v->tokens->last;
-      cp_token tok = {};
+      cp_token tok;
+      memset (&tok, 0, sizeof (tok));
       tok.type = CPP_PRAGMA;
       tok.keyword = RID_MAX;
       tok.u.value = build_int_cst (NULL, v->dir->id);
@@ -12029,13 +12031,14 @@  cp_parser_handle_statement_omp_attributes (cp_parser *parser, tree attrs)
       lexer->buffer->quick_push (tok);
       while (++first < last)
 	lexer->buffer->quick_push (*first);
-      tok = {};
+      memset (&tok, 0, sizeof (tok));
       tok.type = CPP_PRAGMA_EOL;
       tok.keyword = RID_MAX;
       tok.location = last->location;
       lexer->buffer->quick_push (tok);
     }
-  cp_token tok = {};
+  cp_token tok;
+  memset (&tok, 0, sizeof (tok));
   tok.type = CPP_EOF;
   tok.keyword = RID_MAX;
   tok.location = lexer->buffer->last ().location;
@@ -32126,8 +32129,9 @@  cp_parser_late_parsing_for_member (cp_parser* parser, tree member_function)
   maybe_begin_member_template_processing (member_function);
 
   /* If the body of the function has not yet been parsed, parse it
-     now.  */
-  if (DECL_PENDING_INLINE_P (member_function))
+     now.  Except if the tokens have been purged (PR c++/39751).  */
+  if (DECL_PENDING_INLINE_P (member_function)
+      && !DECL_PENDING_INLINE_INFO (member_function)->first->purged_p)
     {
       tree function_scope;
       cp_token_cache *tokens;
@@ -45693,7 +45697,8 @@  cp_parser_late_parsing_omp_declare_simd (cp_parser *parser, tree attrs)
 		    lexer->debugging_p = parser->lexer->debugging_p;
 		  }
 		vec_safe_reserve (lexer->buffer, (last - first) + 2);
-		cp_token tok = {};
+		cp_token tok;
+		memset (&tok, 0, sizeof (tok));
 		tok.type = CPP_PRAGMA;
 		tok.keyword = RID_MAX;
 		tok.u.value = build_int_cst (NULL, PRAGMA_OMP_DECLARE);
@@ -45701,12 +45706,12 @@  cp_parser_late_parsing_omp_declare_simd (cp_parser *parser, tree attrs)
 		lexer->buffer->quick_push (tok);
 		while (++first < last)
 		  lexer->buffer->quick_push (*first);
-		tok = {};
+		memset (&tok, 0, sizeof (tok));
 		tok.type = CPP_PRAGMA_EOL;
 		tok.keyword = RID_MAX;
 		tok.location = last->location;
 		lexer->buffer->quick_push (tok);
-		tok = {};
+		memset (&tok, 0, sizeof (tok));
 		tok.type = CPP_EOF;
 		tok.keyword = RID_MAX;
 		tok.location = last->location;
diff --git a/gcc/testsuite/g++.dg/pr39751.C b/gcc/testsuite/g++.dg/pr39751.C
new file mode 100644
index 0000000..91b09ac
--- /dev/null
+++ b/gcc/testsuite/g++.dg/pr39751.C
@@ -0,0 +1,11 @@ 
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+template < typename >
+struct A
+{
+A < struct
+{
+f () :
+
+// { dg-excess-errors "" }