[v2] c++: Reject UDLs in certain contexts [PR105300]

Message ID Y3gazoJNHo0bHBR9@redhat.com
State Accepted
Headers
Series [v2] c++: Reject UDLs in certain contexts [PR105300] |

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snail/gcc-patch-check success Github commit url

Commit Message

Marek Polacek Nov. 18, 2022, 11:52 p.m. UTC
  On Thu, Nov 17, 2022 at 07:06:34PM -0500, Jason Merrill wrote:
> On 11/16/22 20:12, Marek Polacek wrote:
> > On Wed, Nov 16, 2022 at 08:22:39AM -0500, Jason Merrill wrote:
> > > On 11/15/22 19:35, Marek Polacek wrote:
> > > > On Tue, Nov 15, 2022 at 06:58:39PM -0500, Jason Merrill wrote:
> > > > > On 11/12/22 06:53, Marek Polacek wrote:
> > > > > > In this PR, we are crashing because we've encountered a UDL where a
> > > > > > string-literal is expected.  This patch makes the parser reject string
> > > > > > and character UDLs in all places where the grammar requires a
> > > > > > string-literal and not a user-defined-string-literal.
> > > > > > 
> > > > > > Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
> > > > > 
> > > > > Since the grammar has
> > > > > 
> > > > > user-defined-string-literal :
> > > > > 	string-literal ud-suffix
> > > > > 
> > > > > maybe we want to move the UDL handling out to a cp_parser_udl_string_literal
> > > > > that calls cp_parser_string_literal?
> > > > 
> > > > Umm, maybe, but the UDL handling code seems to be too entrenched in
> > > > cp_parser_string_literal and I don't think it's going to be easy to extract
> > > > it :/.
> > > 
> > > Fair enough; maybe a wrapper, then?
> > 
> > As in, have a cp_parser_udl_string_literal wrapper that calls
> > cp_parser_string_literal with udl_ok=true, rename cp_parser_string_literal,
> > introduce a new cp_parser_string_literal wrapper that passes udl_ok=false?
> 
> That's what I was thinking.  And the new cp_parser_string_literal could also
> omit the lookup_udlit parm.
> 
> > One problem with cp_parser_udl_string_literal is that it's too similar to
> > cp_parser_userdef_string_literal, which would be confusing, I think.
> 
> True, probably better to use that name instead, and rename the current one
> to something like finish_userdef_string_literal

Sounds good, here's the patch.

Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?

-- >8 --
In this PR, we are crashing because we've encountered a UDL where a
string-literal is expected.  This patch makes the parser reject string
and character UDLs in all places where the grammar requires a
string-literal and not a user-defined-string-literal.

I've introduced two new wrappers; the existing cp_parser_string_literal
was renamed to cp_parser_string_literal_common and should not be called
directly.  finish_userdef_string_literal is renamed from
cp_parser_userdef_string_literal.

	PR c++/105300

gcc/c-family/ChangeLog:

	* c-pragma.cc (handle_pragma_message): Warn for CPP_STRING_USERDEF.

gcc/cp/ChangeLog:

	* parser.cc: Remove unnecessary forward declarations.
	(cp_parser_string_literal): New wrapper.
	(cp_parser_string_literal_common): Renamed from
	cp_parser_string_literal.  Add a bool parameter.  Give an error when
	UDLs are not permitted.
	(cp_parser_userdef_string_literal): New wrapper.
	(finish_userdef_string_literal): Renamed from
	cp_parser_userdef_string_literal.
	(cp_parser_primary_expression): Call cp_parser_userdef_string_literal
	instead of cp_parser_string_literal.
	(cp_parser_linkage_specification): Move a variable declaration closer
	to its first use.
	(cp_parser_static_assert): Likewise.
	(cp_parser_operator): Call cp_parser_userdef_string_literal instead of
	cp_parser_string_literal.
	(cp_parser_asm_definition): Move a variable declaration closer to its
	first use.
	(cp_parser_asm_specification_opt): Move variable declarations closer to
	their first use.
	(cp_parser_asm_operand_list): Likewise.
	(cp_parser_asm_clobber_list): Likewise.

gcc/testsuite/ChangeLog:

	* g++.dg/cpp0x/udlit-error1.C: New test.
---
 gcc/c-family/c-pragma.cc                  |   3 +
 gcc/cp/parser.cc                          | 131 ++++++++++++++--------
 gcc/testsuite/g++.dg/cpp0x/udlit-error1.C |  21 ++++
 3 files changed, 111 insertions(+), 44 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/cpp0x/udlit-error1.C


base-commit: 1c4a7881c492790eaad9aec1bcc2c1370f41740f
  

Comments

Jason Merrill Nov. 19, 2022, 1:39 a.m. UTC | #1
On 11/18/22 18:52, Marek Polacek wrote:
> On Thu, Nov 17, 2022 at 07:06:34PM -0500, Jason Merrill wrote:
>> On 11/16/22 20:12, Marek Polacek wrote:
>>> On Wed, Nov 16, 2022 at 08:22:39AM -0500, Jason Merrill wrote:
>>>> On 11/15/22 19:35, Marek Polacek wrote:
>>>>> On Tue, Nov 15, 2022 at 06:58:39PM -0500, Jason Merrill wrote:
>>>>>> On 11/12/22 06:53, Marek Polacek wrote:
>>>>>>> In this PR, we are crashing because we've encountered a UDL where a
>>>>>>> string-literal is expected.  This patch makes the parser reject string
>>>>>>> and character UDLs in all places where the grammar requires a
>>>>>>> string-literal and not a user-defined-string-literal.
>>>>>>>
>>>>>>> Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
>>>>>>
>>>>>> Since the grammar has
>>>>>>
>>>>>> user-defined-string-literal :
>>>>>> 	string-literal ud-suffix
>>>>>>
>>>>>> maybe we want to move the UDL handling out to a cp_parser_udl_string_literal
>>>>>> that calls cp_parser_string_literal?
>>>>>
>>>>> Umm, maybe, but the UDL handling code seems to be too entrenched in
>>>>> cp_parser_string_literal and I don't think it's going to be easy to extract
>>>>> it :/.
>>>>
>>>> Fair enough; maybe a wrapper, then?
>>>
>>> As in, have a cp_parser_udl_string_literal wrapper that calls
>>> cp_parser_string_literal with udl_ok=true, rename cp_parser_string_literal,
>>> introduce a new cp_parser_string_literal wrapper that passes udl_ok=false?
>>
>> That's what I was thinking.  And the new cp_parser_string_literal could also
>> omit the lookup_udlit parm.
>>
>>> One problem with cp_parser_udl_string_literal is that it's too similar to
>>> cp_parser_userdef_string_literal, which would be confusing, I think.
>>
>> True, probably better to use that name instead, and rename the current one
>> to something like finish_userdef_string_literal
> 
> Sounds good, here's the patch.
> 
> Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
> 
> -- >8 --
> In this PR, we are crashing because we've encountered a UDL where a
> string-literal is expected.  This patch makes the parser reject string
> and character UDLs in all places where the grammar requires a
> string-literal and not a user-defined-string-literal.
> 
> I've introduced two new wrappers; the existing cp_parser_string_literal
> was renamed to cp_parser_string_literal_common and should not be called
> directly.  finish_userdef_string_literal is renamed from
> cp_parser_userdef_string_literal.
> 
> 	PR c++/105300
> 
> gcc/c-family/ChangeLog:
> 
> 	* c-pragma.cc (handle_pragma_message): Warn for CPP_STRING_USERDEF.
> 
> gcc/cp/ChangeLog:
> 
> 	* parser.cc: Remove unnecessary forward declarations.
> 	(cp_parser_string_literal): New wrapper.
> 	(cp_parser_string_literal_common): Renamed from
> 	cp_parser_string_literal.  Add a bool parameter.  Give an error when
> 	UDLs are not permitted.
> 	(cp_parser_userdef_string_literal): New wrapper.
> 	(finish_userdef_string_literal): Renamed from
> 	cp_parser_userdef_string_literal.
> 	(cp_parser_primary_expression): Call cp_parser_userdef_string_literal
> 	instead of cp_parser_string_literal.
> 	(cp_parser_linkage_specification): Move a variable declaration closer
> 	to its first use.
> 	(cp_parser_static_assert): Likewise.
> 	(cp_parser_operator): Call cp_parser_userdef_string_literal instead of
> 	cp_parser_string_literal.
> 	(cp_parser_asm_definition): Move a variable declaration closer to its
> 	first use.
> 	(cp_parser_asm_specification_opt): Move variable declarations closer to
> 	their first use.
> 	(cp_parser_asm_operand_list): Likewise.
> 	(cp_parser_asm_clobber_list): Likewise.
> 
> gcc/testsuite/ChangeLog:
> 
> 	* g++.dg/cpp0x/udlit-error1.C: New test.
> ---
>   gcc/c-family/c-pragma.cc                  |   3 +
>   gcc/cp/parser.cc                          | 131 ++++++++++++++--------
>   gcc/testsuite/g++.dg/cpp0x/udlit-error1.C |  21 ++++
>   3 files changed, 111 insertions(+), 44 deletions(-)
>   create mode 100644 gcc/testsuite/g++.dg/cpp0x/udlit-error1.C
> 
> diff --git a/gcc/c-family/c-pragma.cc b/gcc/c-family/c-pragma.cc
> index 142a46441ac..49f405b605b 100644
> --- a/gcc/c-family/c-pragma.cc
> +++ b/gcc/c-family/c-pragma.cc
> @@ -1390,6 +1390,9 @@ handle_pragma_message (cpp_reader *)
>       }
>     else if (token == CPP_STRING)
>       message = x;
> +  else if (token == CPP_STRING_USERDEF)
> +    GCC_BAD ("string literal with user-defined suffix is invalid in this "
> +	     "context");
>     else
>       GCC_BAD ("expected a string after %<#pragma message%>");
>   
> diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc
> index c5929a6cc5f..e3bd94ffe11 100644
> --- a/gcc/cp/parser.cc
> +++ b/gcc/cp/parser.cc
> @@ -2223,16 +2223,8 @@ pop_unparsed_function_queues (cp_parser *parser)
>   
>   /* Lexical conventions [gram.lex]  */
>   
> -static cp_expr cp_parser_identifier
> -  (cp_parser *);
> -static cp_expr cp_parser_string_literal
> -  (cp_parser *, bool, bool, bool);
> -static cp_expr cp_parser_userdef_char_literal
> -  (cp_parser *);
> -static tree cp_parser_userdef_string_literal
> +static tree finish_userdef_string_literal
>     (tree);
> -static cp_expr cp_parser_userdef_numeric_literal
> -  (cp_parser *);
>   
>   /* Basic concepts [gram.basic]  */
>   
> @@ -4398,11 +4390,15 @@ cp_parser_identifier (cp_parser* parser)
>       return error_mark_node;
>   }
>   
> -/* Parse a sequence of adjacent string constants.  Returns a
> +/* Worker for cp_parser_string_literal and cp_parser_userdef_string_literal.
> +   Do not call this directly; use either of the above.
> +
> +   Parse a sequence of adjacent string constants.  Return a
>      TREE_STRING representing the combined, nul-terminated string
>      constant.  If TRANSLATE is true, translate the string to the
>      execution character set.  If WIDE_OK is true, a wide string is
> -   invalid here.
> +   valid here.  If UDL_OK is true, a string literal with user-defined
> +   suffix can be used in this context.
>   
>      C++98 [lex.string] says that if a narrow string literal token is
>      adjacent to a wide string literal token, the behavior is undefined.
> @@ -4412,9 +4408,11 @@ cp_parser_identifier (cp_parser* parser)
>      This code is largely lifted from lex_string() in c-lex.cc.
>   
>      FUTURE: ObjC++ will need to handle @-strings here.  */
> +
>   static cp_expr
> -cp_parser_string_literal (cp_parser *parser, bool translate, bool wide_ok,
> -			  bool lookup_udlit = true)
> +cp_parser_string_literal_common (cp_parser *parser, bool translate,
> +				 bool wide_ok, bool udl_ok,
> +				 bool lookup_udlit)
>   {
>     tree value;
>     size_t count;
> @@ -4439,6 +4437,12 @@ cp_parser_string_literal (cp_parser *parser, bool translate, bool wide_ok,
>   
>     if (cpp_userdef_string_p (tok->type))
>       {
> +      if (!udl_ok)
> +	{
> +	  error_at (loc, "string literal with user-defined suffix "
> +		    "is invalid in this context");
> +	  return error_mark_node;
> +	}
>         string_tree = USERDEF_LITERAL_VALUE (tok->u.value);
>         curr_type = cpp_userdef_string_remove_type (tok->type);
>         curr_tok_is_userdef_p = true;
> @@ -4529,6 +4533,12 @@ cp_parser_string_literal (cp_parser *parser, bool translate, bool wide_ok,
>   	  tok = cp_lexer_peek_token (parser->lexer);
>   	  if (cpp_userdef_string_p (tok->type))
>   	    {
> +	      if (!udl_ok)
> +		{
> +		  error_at (loc, "string literal with user-defined suffix "
> +			    "is invalid in this context");
> +		  return error_mark_node;
> +		}
>   	      string_tree = USERDEF_LITERAL_VALUE (tok->u.value);
>   	      curr_type = cpp_userdef_string_remove_type (tok->type);
>   	      curr_tok_is_userdef_p = true;
> @@ -4598,7 +4608,7 @@ cp_parser_string_literal (cp_parser *parser, bool translate, bool wide_ok,
>   	  tree literal = build_userdef_literal (suffix_id, value,
>   						OT_NONE, NULL_TREE);
>   	  if (lookup_udlit)
> -	    value = cp_parser_userdef_string_literal (literal);
> +	    value = finish_userdef_string_literal (literal);
>   	  else
>   	    value = literal;
>   	}
> @@ -4616,6 +4626,38 @@ cp_parser_string_literal (cp_parser *parser, bool translate, bool wide_ok,
>     return cp_expr (value, loc);
>   }
>   
> +/* Parse a sequence of adjacent string constants.  Return a TREE_STRING
> +   representing the combined, nul-terminated string constant.  If
> +   TRANSLATE is true, translate the string to the execution character set.
> +   If WIDE_OK is true, a wide string is valid here.
> +
> +   This function issues an error if a user defined string literal is
> +   encountered; use cp_parser_userdef_string_literal if UDLs are allowed.  */
> +
> +static inline cp_expr
> +cp_parser_string_literal (cp_parser *parser, bool translate, bool wide_ok)
> +{
> +  return cp_parser_string_literal_common (parser, translate, wide_ok,
> +					  /*udl_ok=*/false,
> +					  /*lookup_udlit=*/false);
> +}
> +
> +/* Parse a string literal or user defined string literal.
> +
> +   user-defined-string-literal :
> +     string-literal ud-suffix
> +
> +   Parameters as for cp_parser_string_literal.  If LOOKUP_UDLIT, perform
> +   a lookup for a suitable template function.  */
> +
> +static inline cp_expr
> +cp_parser_userdef_string_literal (cp_parser *parser, bool translate,
> +				  bool wide_ok, bool lookup_udlit = true)

I think this function doesn't need the translate and wide_ok parms, they 
can always be true.

> +{
> +  return cp_parser_string_literal_common (parser, translate, wide_ok,
> +					  /*udl_ok=*/true, lookup_udlit);
> +}
> +
>   /* Look up a literal operator with the name and the exact arguments.  */
>   
>   static tree
> @@ -4913,7 +4955,7 @@ cp_parser_userdef_numeric_literal (cp_parser *parser)
>      as arguments.  */
>   
>   static tree
> -cp_parser_userdef_string_literal (tree literal)
> +finish_userdef_string_literal (tree literal)
>   {
>     tree suffix_id = USERDEF_LITERAL_SUFFIX_ID (literal);
>     tree name = cp_literal_operator_id (IDENTIFIER_POINTER (suffix_id));
> @@ -5652,10 +5694,10 @@ cp_parser_primary_expression (cp_parser *parser,
>       case CPP_UTF8STRING_USERDEF:
>         /* ??? Should wide strings be allowed when parser->translate_strings_p
>   	 is false (i.e. in attributes)?  If not, we can kill the third
> -	 argument to cp_parser_string_literal.  */

I think the answer to this old question is no: if we have an 
encoding-prefix, we should be translating.

> -      return (cp_parser_string_literal (parser,
> -					parser->translate_strings_p,
> -					true)
> +	 argument to cp_parser_{,userdef}string_literal.  */
> +      return (cp_parser_userdef_string_literal (parser,
> +						parser->translate_strings_p,
> +						/*wide_ok=*/true)

For CPP_*STRING* without _USERDEF, we should still call 
cp_parser_string_literal.

>   	      .maybe_add_location_wrapper ());
>   
>       case CPP_OPEN_PAREN:
> @@ -16161,15 +16203,14 @@ cp_parser_function_specifier_opt (cp_parser* parser,
>   static void
>   cp_parser_linkage_specification (cp_parser* parser, tree prefix_attr)
>   {
> -  tree linkage;
> -
>     /* Look for the `extern' keyword.  */
>     cp_token *extern_token
>       = cp_parser_require_keyword (parser, RID_EXTERN, RT_EXTERN);
>   
>     /* Look for the string-literal.  */
>     cp_token *string_token = cp_lexer_peek_token (parser->lexer);
> -  linkage = cp_parser_string_literal (parser, false, false);
> +  tree linkage = cp_parser_string_literal (parser, /*translate=*/false,
> +					   /*wide_ok=*/false);
>   
>     /* Transform the literal into an identifier.  If the literal is a
>        wide-character string, or contains embedded NULs, then we can't
> @@ -16299,9 +16340,8 @@ cp_parser_static_assert(cp_parser *parser, bool member_p)
>         cp_parser_require (parser, CPP_COMMA, RT_COMMA);
>   
>         /* Parse the string-literal message.  */
> -      message = cp_parser_string_literal (parser,
> -                                	  /*translate=*/false,
> -                                	  /*wide_ok=*/true);
> +      message = cp_parser_string_literal (parser, /*translate=*/false,
> +					  /*wide_ok=*/true);
>   
>         /* A `)' completes the static assertion.  */
>         if (!parens.require_close (parser))
> @@ -17349,7 +17389,6 @@ cp_parser_operator (cp_parser* parser, location_t start_loc)
>       case CPP_STRING16_USERDEF:
>       case CPP_STRING32_USERDEF:
>         {
> -	cp_expr str;
>   	tree string_tree;
>   	int sz, len;
>   
> @@ -17357,8 +17396,10 @@ cp_parser_operator (cp_parser* parser, location_t start_loc)
>   	  maybe_warn_cpp0x (CPP0X_USER_DEFINED_LITERALS);
>   
>   	/* Consume the string.  */
> -	str = cp_parser_string_literal (parser, /*translate=*/true,
> -				      /*wide_ok=*/true, /*lookup_udlit=*/false);
> +	cp_expr str = cp_parser_userdef_string_literal (parser,
> +							/*translate=*/true,
> +							/*wide_ok=*/true,
> +							/*lookup_udlit=*/false);
>   	if (str == error_mark_node)
>   	  return error_mark_node;
>   	else if (TREE_CODE (str) == USERDEF_LITERAL)
> @@ -21975,7 +22016,6 @@ cp_parser_using_directive (cp_parser* parser)
>   static void
>   cp_parser_asm_definition (cp_parser* parser)
>   {
> -  tree string;
>     tree outputs = NULL_TREE;
>     tree inputs = NULL_TREE;
>     tree clobbers = NULL_TREE;
> @@ -22083,7 +22123,8 @@ cp_parser_asm_definition (cp_parser* parser)
>     if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN))
>       return;
>     /* Look for the string.  */
> -  string = cp_parser_string_literal (parser, false, false);
> +  tree string = cp_parser_string_literal (parser, /*translate=*/false,
> +					  /*wide_ok=*/false);
>     if (string == error_mark_node)
>       {
>         cp_parser_skip_to_closing_parenthesis (parser, true, false,
> @@ -28485,11 +28526,8 @@ cp_parser_yield_expression (cp_parser* parser)
>   static tree
>   cp_parser_asm_specification_opt (cp_parser* parser)
>   {
> -  cp_token *token;
> -  tree asm_specification;
> -
>     /* Peek at the next token.  */
> -  token = cp_lexer_peek_token (parser->lexer);
> +  cp_token *token = cp_lexer_peek_token (parser->lexer);
>     /* If the next token isn't the `asm' keyword, then there's no
>        asm-specification.  */
>     if (!cp_parser_is_keyword (token, RID_ASM))
> @@ -28502,7 +28540,9 @@ cp_parser_asm_specification_opt (cp_parser* parser)
>     parens.require_open (parser);
>   
>     /* Look for the string-literal.  */
> -  asm_specification = cp_parser_string_literal (parser, false, false);
> +  tree asm_specification = cp_parser_string_literal (parser,
> +						     /*translate=*/false,
> +						     /*wide_ok=*/false);
>   
>     /* Look for the `)'.  */
>     parens.require_close (parser);
> @@ -28535,8 +28575,6 @@ cp_parser_asm_operand_list (cp_parser* parser)
>   
>     while (true)
>       {
> -      tree string_literal;
> -      tree expression;
>         tree name;
>   
>         if (cp_lexer_next_token_is (parser->lexer, CPP_OPEN_SQUARE))
> @@ -28554,13 +28592,15 @@ cp_parser_asm_operand_list (cp_parser* parser)
>         else
>   	name = NULL_TREE;
>         /* Look for the string-literal.  */
> -      string_literal = cp_parser_string_literal (parser, false, false);
> +      tree string_literal = cp_parser_string_literal (parser,
> +						      /*translate=*/false,
> +						      /*wide_ok=*/false);
>   
>         /* Look for the `('.  */
>         matching_parens parens;
>         parens.require_open (parser);
>         /* Parse the expression.  */
> -      expression = cp_parser_expression (parser);
> +      tree expression = cp_parser_expression (parser);
>         /* Look for the `)'.  */
>         parens.require_close (parser);
>   
> @@ -28600,10 +28640,10 @@ cp_parser_asm_clobber_list (cp_parser* parser)
>   
>     while (true)
>       {
> -      tree string_literal;
> -
>         /* Look for the string literal.  */
> -      string_literal = cp_parser_string_literal (parser, false, false);
> +      tree string_literal = cp_parser_string_literal (parser,
> +						      /*translate=*/false,
> +						      /*wide_ok=*/false);
>         /* Add it to the list.  */
>         clobbers = tree_cons (NULL_TREE, string_literal, clobbers);
>         /* If the next token is not a `,', then the list is
> @@ -45763,7 +45803,9 @@ cp_parser_omp_context_selector (cp_parser *parser, tree set, bool has_parms_p)
>   		      cp_lexer_consume_token (parser->lexer);
>   		    }
>   		  else if (cp_lexer_next_token_is (parser->lexer, CPP_STRING))
> -		    value = cp_parser_string_literal (parser, false, false);
> +		    value = cp_parser_string_literal (parser,
> +						      /*translate=*/false,
> +						      /*wide_ok=*/false);
>   		  else
>   		    {
>   		      cp_parser_error (parser, "expected identifier or "
> @@ -48785,7 +48827,8 @@ pragma_lex (tree *value, location_t *loc)
>     if (ret == CPP_PRAGMA_EOL)
>       ret = CPP_EOF;
>     else if (ret == CPP_STRING)
> -    *value = cp_parser_string_literal (the_parser, false, false);
> +    *value = cp_parser_string_literal (the_parser, /*translate=*/false,
> +				       /*wide_ok=*/false);
>     else
>       {
>         if (ret == CPP_KEYWORD)
> diff --git a/gcc/testsuite/g++.dg/cpp0x/udlit-error1.C b/gcc/testsuite/g++.dg/cpp0x/udlit-error1.C
> new file mode 100644
> index 00000000000..66e300e350f
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp0x/udlit-error1.C
> @@ -0,0 +1,21 @@
> +// PR c++/105300
> +// { dg-do compile { target c++11 } }
> +
> +void operator""_x(const char *, decltype(sizeof(0)));
> +
> +#include ""_x		  // { dg-error "include expects" }
> +#line ""_x		  // { dg-error "not a positive integer" }
> +#if __has_include(""_x)	  // { dg-error "requires a header-name" }
> +#endif
> +
> +#pragma message "hi"_x	  // { dg-warning "string literal with user-defined suffix is invalid in this context" }
> +
> +extern "C"_x { void g(); } // { dg-error "before user-defined string literal" }
> +static_assert(true, "foo"_x); // { dg-error "string literal with user-defined suffix is invalid in this context|expected" }
> +
> +[[deprecated("oof"_x)]]
> +void
> +lol () // { dg-error "not a string" }
> +{
> +  asm (""_x); // { dg-error "string literal with user-defined suffix is invalid in this context" }
> +}
> 
> base-commit: 1c4a7881c492790eaad9aec1bcc2c1370f41740f
  

Patch

diff --git a/gcc/c-family/c-pragma.cc b/gcc/c-family/c-pragma.cc
index 142a46441ac..49f405b605b 100644
--- a/gcc/c-family/c-pragma.cc
+++ b/gcc/c-family/c-pragma.cc
@@ -1390,6 +1390,9 @@  handle_pragma_message (cpp_reader *)
     }
   else if (token == CPP_STRING)
     message = x;
+  else if (token == CPP_STRING_USERDEF)
+    GCC_BAD ("string literal with user-defined suffix is invalid in this "
+	     "context");
   else
     GCC_BAD ("expected a string after %<#pragma message%>");
 
diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc
index c5929a6cc5f..e3bd94ffe11 100644
--- a/gcc/cp/parser.cc
+++ b/gcc/cp/parser.cc
@@ -2223,16 +2223,8 @@  pop_unparsed_function_queues (cp_parser *parser)
 
 /* Lexical conventions [gram.lex]  */
 
-static cp_expr cp_parser_identifier
-  (cp_parser *);
-static cp_expr cp_parser_string_literal
-  (cp_parser *, bool, bool, bool);
-static cp_expr cp_parser_userdef_char_literal
-  (cp_parser *);
-static tree cp_parser_userdef_string_literal
+static tree finish_userdef_string_literal
   (tree);
-static cp_expr cp_parser_userdef_numeric_literal
-  (cp_parser *);
 
 /* Basic concepts [gram.basic]  */
 
@@ -4398,11 +4390,15 @@  cp_parser_identifier (cp_parser* parser)
     return error_mark_node;
 }
 
-/* Parse a sequence of adjacent string constants.  Returns a
+/* Worker for cp_parser_string_literal and cp_parser_userdef_string_literal.
+   Do not call this directly; use either of the above.
+
+   Parse a sequence of adjacent string constants.  Return a
    TREE_STRING representing the combined, nul-terminated string
    constant.  If TRANSLATE is true, translate the string to the
    execution character set.  If WIDE_OK is true, a wide string is
-   invalid here.
+   valid here.  If UDL_OK is true, a string literal with user-defined
+   suffix can be used in this context.
 
    C++98 [lex.string] says that if a narrow string literal token is
    adjacent to a wide string literal token, the behavior is undefined.
@@ -4412,9 +4408,11 @@  cp_parser_identifier (cp_parser* parser)
    This code is largely lifted from lex_string() in c-lex.cc.
 
    FUTURE: ObjC++ will need to handle @-strings here.  */
+
 static cp_expr
-cp_parser_string_literal (cp_parser *parser, bool translate, bool wide_ok,
-			  bool lookup_udlit = true)
+cp_parser_string_literal_common (cp_parser *parser, bool translate,
+				 bool wide_ok, bool udl_ok,
+				 bool lookup_udlit)
 {
   tree value;
   size_t count;
@@ -4439,6 +4437,12 @@  cp_parser_string_literal (cp_parser *parser, bool translate, bool wide_ok,
 
   if (cpp_userdef_string_p (tok->type))
     {
+      if (!udl_ok)
+	{
+	  error_at (loc, "string literal with user-defined suffix "
+		    "is invalid in this context");
+	  return error_mark_node;
+	}
       string_tree = USERDEF_LITERAL_VALUE (tok->u.value);
       curr_type = cpp_userdef_string_remove_type (tok->type);
       curr_tok_is_userdef_p = true;
@@ -4529,6 +4533,12 @@  cp_parser_string_literal (cp_parser *parser, bool translate, bool wide_ok,
 	  tok = cp_lexer_peek_token (parser->lexer);
 	  if (cpp_userdef_string_p (tok->type))
 	    {
+	      if (!udl_ok)
+		{
+		  error_at (loc, "string literal with user-defined suffix "
+			    "is invalid in this context");
+		  return error_mark_node;
+		}
 	      string_tree = USERDEF_LITERAL_VALUE (tok->u.value);
 	      curr_type = cpp_userdef_string_remove_type (tok->type);
 	      curr_tok_is_userdef_p = true;
@@ -4598,7 +4608,7 @@  cp_parser_string_literal (cp_parser *parser, bool translate, bool wide_ok,
 	  tree literal = build_userdef_literal (suffix_id, value,
 						OT_NONE, NULL_TREE);
 	  if (lookup_udlit)
-	    value = cp_parser_userdef_string_literal (literal);
+	    value = finish_userdef_string_literal (literal);
 	  else
 	    value = literal;
 	}
@@ -4616,6 +4626,38 @@  cp_parser_string_literal (cp_parser *parser, bool translate, bool wide_ok,
   return cp_expr (value, loc);
 }
 
+/* Parse a sequence of adjacent string constants.  Return a TREE_STRING
+   representing the combined, nul-terminated string constant.  If
+   TRANSLATE is true, translate the string to the execution character set.
+   If WIDE_OK is true, a wide string is valid here.
+
+   This function issues an error if a user defined string literal is
+   encountered; use cp_parser_userdef_string_literal if UDLs are allowed.  */
+
+static inline cp_expr
+cp_parser_string_literal (cp_parser *parser, bool translate, bool wide_ok)
+{
+  return cp_parser_string_literal_common (parser, translate, wide_ok,
+					  /*udl_ok=*/false,
+					  /*lookup_udlit=*/false);
+}
+
+/* Parse a string literal or user defined string literal.
+
+   user-defined-string-literal :
+     string-literal ud-suffix
+
+   Parameters as for cp_parser_string_literal.  If LOOKUP_UDLIT, perform
+   a lookup for a suitable template function.  */
+
+static inline cp_expr
+cp_parser_userdef_string_literal (cp_parser *parser, bool translate,
+				  bool wide_ok, bool lookup_udlit = true)
+{
+  return cp_parser_string_literal_common (parser, translate, wide_ok,
+					  /*udl_ok=*/true, lookup_udlit);
+}
+
 /* Look up a literal operator with the name and the exact arguments.  */
 
 static tree
@@ -4913,7 +4955,7 @@  cp_parser_userdef_numeric_literal (cp_parser *parser)
    as arguments.  */
 
 static tree
-cp_parser_userdef_string_literal (tree literal)
+finish_userdef_string_literal (tree literal)
 {
   tree suffix_id = USERDEF_LITERAL_SUFFIX_ID (literal);
   tree name = cp_literal_operator_id (IDENTIFIER_POINTER (suffix_id));
@@ -5652,10 +5694,10 @@  cp_parser_primary_expression (cp_parser *parser,
     case CPP_UTF8STRING_USERDEF:
       /* ??? Should wide strings be allowed when parser->translate_strings_p
 	 is false (i.e. in attributes)?  If not, we can kill the third
-	 argument to cp_parser_string_literal.  */
-      return (cp_parser_string_literal (parser,
-					parser->translate_strings_p,
-					true)
+	 argument to cp_parser_{,userdef}string_literal.  */
+      return (cp_parser_userdef_string_literal (parser,
+						parser->translate_strings_p,
+						/*wide_ok=*/true)
 	      .maybe_add_location_wrapper ());
 
     case CPP_OPEN_PAREN:
@@ -16161,15 +16203,14 @@  cp_parser_function_specifier_opt (cp_parser* parser,
 static void
 cp_parser_linkage_specification (cp_parser* parser, tree prefix_attr)
 {
-  tree linkage;
-
   /* Look for the `extern' keyword.  */
   cp_token *extern_token
     = cp_parser_require_keyword (parser, RID_EXTERN, RT_EXTERN);
 
   /* Look for the string-literal.  */
   cp_token *string_token = cp_lexer_peek_token (parser->lexer);
-  linkage = cp_parser_string_literal (parser, false, false);
+  tree linkage = cp_parser_string_literal (parser, /*translate=*/false,
+					   /*wide_ok=*/false);
 
   /* Transform the literal into an identifier.  If the literal is a
      wide-character string, or contains embedded NULs, then we can't
@@ -16299,9 +16340,8 @@  cp_parser_static_assert(cp_parser *parser, bool member_p)
       cp_parser_require (parser, CPP_COMMA, RT_COMMA);
 
       /* Parse the string-literal message.  */
-      message = cp_parser_string_literal (parser,
-                                	  /*translate=*/false,
-                                	  /*wide_ok=*/true);
+      message = cp_parser_string_literal (parser, /*translate=*/false,
+					  /*wide_ok=*/true);
 
       /* A `)' completes the static assertion.  */
       if (!parens.require_close (parser))
@@ -17349,7 +17389,6 @@  cp_parser_operator (cp_parser* parser, location_t start_loc)
     case CPP_STRING16_USERDEF:
     case CPP_STRING32_USERDEF:
       {
-	cp_expr str;
 	tree string_tree;
 	int sz, len;
 
@@ -17357,8 +17396,10 @@  cp_parser_operator (cp_parser* parser, location_t start_loc)
 	  maybe_warn_cpp0x (CPP0X_USER_DEFINED_LITERALS);
 
 	/* Consume the string.  */
-	str = cp_parser_string_literal (parser, /*translate=*/true,
-				      /*wide_ok=*/true, /*lookup_udlit=*/false);
+	cp_expr str = cp_parser_userdef_string_literal (parser,
+							/*translate=*/true,
+							/*wide_ok=*/true,
+							/*lookup_udlit=*/false);
 	if (str == error_mark_node)
 	  return error_mark_node;
 	else if (TREE_CODE (str) == USERDEF_LITERAL)
@@ -21975,7 +22016,6 @@  cp_parser_using_directive (cp_parser* parser)
 static void
 cp_parser_asm_definition (cp_parser* parser)
 {
-  tree string;
   tree outputs = NULL_TREE;
   tree inputs = NULL_TREE;
   tree clobbers = NULL_TREE;
@@ -22083,7 +22123,8 @@  cp_parser_asm_definition (cp_parser* parser)
   if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN))
     return;
   /* Look for the string.  */
-  string = cp_parser_string_literal (parser, false, false);
+  tree string = cp_parser_string_literal (parser, /*translate=*/false,
+					  /*wide_ok=*/false);
   if (string == error_mark_node)
     {
       cp_parser_skip_to_closing_parenthesis (parser, true, false,
@@ -28485,11 +28526,8 @@  cp_parser_yield_expression (cp_parser* parser)
 static tree
 cp_parser_asm_specification_opt (cp_parser* parser)
 {
-  cp_token *token;
-  tree asm_specification;
-
   /* Peek at the next token.  */
-  token = cp_lexer_peek_token (parser->lexer);
+  cp_token *token = cp_lexer_peek_token (parser->lexer);
   /* If the next token isn't the `asm' keyword, then there's no
      asm-specification.  */
   if (!cp_parser_is_keyword (token, RID_ASM))
@@ -28502,7 +28540,9 @@  cp_parser_asm_specification_opt (cp_parser* parser)
   parens.require_open (parser);
 
   /* Look for the string-literal.  */
-  asm_specification = cp_parser_string_literal (parser, false, false);
+  tree asm_specification = cp_parser_string_literal (parser,
+						     /*translate=*/false,
+						     /*wide_ok=*/false);
 
   /* Look for the `)'.  */
   parens.require_close (parser);
@@ -28535,8 +28575,6 @@  cp_parser_asm_operand_list (cp_parser* parser)
 
   while (true)
     {
-      tree string_literal;
-      tree expression;
       tree name;
 
       if (cp_lexer_next_token_is (parser->lexer, CPP_OPEN_SQUARE))
@@ -28554,13 +28592,15 @@  cp_parser_asm_operand_list (cp_parser* parser)
       else
 	name = NULL_TREE;
       /* Look for the string-literal.  */
-      string_literal = cp_parser_string_literal (parser, false, false);
+      tree string_literal = cp_parser_string_literal (parser,
+						      /*translate=*/false,
+						      /*wide_ok=*/false);
 
       /* Look for the `('.  */
       matching_parens parens;
       parens.require_open (parser);
       /* Parse the expression.  */
-      expression = cp_parser_expression (parser);
+      tree expression = cp_parser_expression (parser);
       /* Look for the `)'.  */
       parens.require_close (parser);
 
@@ -28600,10 +28640,10 @@  cp_parser_asm_clobber_list (cp_parser* parser)
 
   while (true)
     {
-      tree string_literal;
-
       /* Look for the string literal.  */
-      string_literal = cp_parser_string_literal (parser, false, false);
+      tree string_literal = cp_parser_string_literal (parser,
+						      /*translate=*/false,
+						      /*wide_ok=*/false);
       /* Add it to the list.  */
       clobbers = tree_cons (NULL_TREE, string_literal, clobbers);
       /* If the next token is not a `,', then the list is
@@ -45763,7 +45803,9 @@  cp_parser_omp_context_selector (cp_parser *parser, tree set, bool has_parms_p)
 		      cp_lexer_consume_token (parser->lexer);
 		    }
 		  else if (cp_lexer_next_token_is (parser->lexer, CPP_STRING))
-		    value = cp_parser_string_literal (parser, false, false);
+		    value = cp_parser_string_literal (parser,
+						      /*translate=*/false,
+						      /*wide_ok=*/false);
 		  else
 		    {
 		      cp_parser_error (parser, "expected identifier or "
@@ -48785,7 +48827,8 @@  pragma_lex (tree *value, location_t *loc)
   if (ret == CPP_PRAGMA_EOL)
     ret = CPP_EOF;
   else if (ret == CPP_STRING)
-    *value = cp_parser_string_literal (the_parser, false, false);
+    *value = cp_parser_string_literal (the_parser, /*translate=*/false,
+				       /*wide_ok=*/false);
   else
     {
       if (ret == CPP_KEYWORD)
diff --git a/gcc/testsuite/g++.dg/cpp0x/udlit-error1.C b/gcc/testsuite/g++.dg/cpp0x/udlit-error1.C
new file mode 100644
index 00000000000..66e300e350f
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/udlit-error1.C
@@ -0,0 +1,21 @@ 
+// PR c++/105300
+// { dg-do compile { target c++11 } }
+
+void operator""_x(const char *, decltype(sizeof(0)));
+
+#include ""_x		  // { dg-error "include expects" }
+#line ""_x		  // { dg-error "not a positive integer" }
+#if __has_include(""_x)	  // { dg-error "requires a header-name" }
+#endif
+
+#pragma message "hi"_x	  // { dg-warning "string literal with user-defined suffix is invalid in this context" }
+
+extern "C"_x { void g(); } // { dg-error "before user-defined string literal" }
+static_assert(true, "foo"_x); // { dg-error "string literal with user-defined suffix is invalid in this context|expected" }
+
+[[deprecated("oof"_x)]]
+void
+lol () // { dg-error "not a string" }
+{
+  asm (""_x); // { dg-error "string literal with user-defined suffix is invalid in this context" }
+}