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

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