libcpp, genmatch: Use gcc_diag instead of printf for libcpp diagnostics

When working on #embed support, or -Wheader-guard or other recent libcpp
changes, I've been annoyed by the libcpp diagnostics being visually
different from normal gcc diagnostics, especially in the area of quoting
stuff in the diagnostic messages.
Normall GCC diagnostics is gcc_diag/gcc_tdiag, one can use
%</%>, %qs etc. in there, while libcpp diagnostics was marked as printf
and in libcpp we've been very creative with quoting stuff, either
no quotes at all, or "something" quoting, or 'something' quoting, or
`something' quoting (but in none of the cases it used colors consistently
with the rest of the compiler).

Now, libcpp diagnostics is always emitted using a callback,
pfile->cb.diagnostic.  On the gcc/ side, this callback is initialized with
genmatch.cc:  cb->diagnostic = diagnostic_cb;
c-family/c-opts.cc:  cb->diagnostic = c_cpp_diagnostic;
fortran/cpp.cc:  cb->diagnostic = cb_cpp_diagnostic;
where the latter two just use diagnostic_report_diagnostic, so actually
support all the gcc_diag stuff, only the genmatch.cc case didn't.

So, the following patch changes genmatch.cc to use pp_format* instead
of vfprintf so that it supports the gcc_diag formatting (pretty-print.o
unfortunately has various dependencies, so had to link genmatch with
libcommon.a libbacktrace.a and tweak Makefile.in so that there are no
circular dependencies) and marks the libcpp diagnostic routines as
gcc_diag rather than printf.  That change resulted in hundreds of
-Wformat-diag new warnings (most of them useful and resulting IMHO in
better diagnostics), so the rest of the patch is changing the format
strings to make -Wformat-diag happy and adjusting the testsuite for
the differences in how is the diagnostic reformatted.

Dunno if some out of GCC tree projects use libcpp, that case would
make it harder because one couldn't use vfprintf in the diagnostic
callback anymore, but there is always David's libdiagnostic which could
be used for that purpose IMHO.

2024-10-12  Jakub Jelinek  <jakub@redhat.com>

libcpp/
	* include/cpplib.h (ATTRIBUTE_CPP_PPDIAG): Define.
	(struct cpp_callbacks): Use ATTRIBUTE_CPP_PPDIAG instead of
	ATTRIBUTE_FPTR_PRINTF on diagnostic callback.
	(cpp_error, cpp_warning, cpp_pedwarning, cpp_warning_syshdr): Use
	ATTRIBUTE_CPP_PPDIAG (3, 4) instead of ATTRIBUTE_PRINTF_3.
	(cpp_warning_at, cpp_pedwarning_at): Use ATTRIBUTE_CPP_PPDIAG (4, 5)
	instead of ATTRIBUTE_PRINTF_4.
	(cpp_error_with_line, cpp_warning_with_line, cpp_pedwarning_with_line,
	cpp_warning_with_line_syshdr): Use ATTRIBUTE_CPP_PPDIAG (5, 6)
	instead of ATTRIBUTE_PRINTF_5.
	(cpp_error_at): Use ATTRIBUTE_CPP_PPDIAG (4, 5) instead of
	ATTRIBUTE_PRINTF_4.
	* Makefile.in (po/$(PACKAGE).pot): Use --language=GCC-source rather
	than --language=c.
	* errors.cc (cpp_diagnostic_at, cpp_diagnostic,
	cpp_diagnostic_with_line): Use ATTRIBUTE_CPP_PPDIAG instead of
	-ATTRIBUTE_FPTR_PRINTF.
	* charset.cc (cpp_host_to_exec_charset, _cpp_valid_ucn, convert_hex,
	convert_oct, convert_escape): Fix up -Wformat-diag warnings.
	(cpp_interpret_string_ranges, count_source_chars): Use
	ATTRIBUTE_CPP_PPDIAG instead of ATTRIBUTE_FPTR_PRINTF.
	(narrow_str_to_charconst): Fix up -Wformat-diag warnings.
	* directives.cc (check_eol_1, directive_diagnostics, lex_macro_node,
	do_undef, glue_header_name, parse_include, do_include_common,
	do_include_next, _cpp_parse_embed_params, do_embed, read_flag,
	do_line, do_linemarker, register_pragma_1, do_pragma_once,
	do_pragma_push_macro, do_pragma_pop_macro, do_pragma_poison,
	do_pragma_system_header, do_pragma_warning_or_error, _cpp_do__Pragma,
	do_else, do_elif, do_endif, parse_answer, do_assert,
	cpp_define_unused): Likewise.
	* expr.cc (cpp_classify_number, parse_defined, eval_token,
	_cpp_parse_expr, reduce, check_promotion): Likewise.
	* files.cc (_cpp_find_file, finish_base64_embed,
	_cpp_pop_file_buffer): Likewise.
	* init.cc (sanity_checks): Likewise.
	* lex.cc (_cpp_process_line_notes, maybe_warn_bidi_on_char,
	_cpp_warn_invalid_utf8, _cpp_skip_block_comment,
	warn_about_normalization, forms_identifier_p, maybe_va_opt_error,
	identifier_diagnostics_on_lex, cpp_maybe_module_directive): Likewise.
	* macro.cc (class vaopt_state, builtin_has_include_1,
	builtin_has_include, builtin_has_embed, _cpp_warn_if_unused_macro,
	_cpp_builtin_macro_text, builtin_macro, stringify_arg,
	_cpp_arguments_ok, collect_args, enter_macro_context,
	_cpp_save_parameter, parse_params, create_iso_definition,
	_cpp_create_definition, check_trad_stringification): Likewise.
	* pch.cc (cpp_valid_state): Likewise.
	* traditional.cc (_cpp_scan_out_logical_line, recursive_macro):
	Likewise.
gcc/
	* Makefile.in (generated_files): Remove {gimple,generic}-match*.
	(generated_match_files): New variable.  Add a dependency of
	$(filter-out $(OBJS-libcommon),$(ALL_HOST_OBJS)) files on those.
	(build/genmatch$(build_exeext)): Depend on and link against
	libcommon.a and $(LIBBACKTRACE).
	* genmatch.cc: Include pretty-print.h and input.h.
	(ggc_internal_cleared_alloc, ggc_free): Remove.
	(fatal): New function.
	(line_table): Remove.
	(linemap_client_expand_location_to_spelling_point): Remove.
	(diagnostic_cb): Use gcc_diag rather than printf format.  Use
	pp_format_verbatim on a temporary pretty_printer instead of
	vfprintf.
	(fatal_at, warning_at): Use gcc_diag rather than printf format.
	(output_line_directive): Rename location_hash to loc_hash.
	(parser::eat_ident, parser::parse_operation, parser::parse_expr,
	parser::parse_pattern, parser::finish_match_operand): Fix up
	-Wformat-diag warnings.
gcc/c-family/
	* c-lex.cc (c_common_has_attribute,
	c_common_lex_availability_macro): Fix up -Wformat-diag warnings.
gcc/testsuite/
	* c-c++-common/cpp/counter-2.c: Adjust expected diagnostics for
	libcpp diagnostic formatting changes.
	* c-c++-common/cpp/embed-3.c: Likewise.
	* c-c++-common/cpp/embed-4.c: Likewise.
	* c-c++-common/cpp/embed-16.c: Likewise.
	* c-c++-common/cpp/embed-18.c: Likewise.
	* c-c++-common/cpp/eof-2.c: Likewise.
	* c-c++-common/cpp/eof-3.c: Likewise.
	* c-c++-common/cpp/fmax-include-depth.c: Likewise.
	* c-c++-common/cpp/has-builtin.c: Likewise.
	* c-c++-common/cpp/line-2.c: Likewise.
	* c-c++-common/cpp/line-3.c: Likewise.
	* c-c++-common/cpp/macro-arg-count-1.c: Likewise.
	* c-c++-common/cpp/macro-arg-count-2.c: Likewise.
	* c-c++-common/cpp/macro-ranges.c: Likewise.
	* c-c++-common/cpp/named-universal-char-escape-4.c: Likewise.
	* c-c++-common/cpp/named-universal-char-escape-5.c: Likewise.
	* c-c++-common/cpp/pr88974.c: Likewise.
	* c-c++-common/cpp/va-opt-error.c: Likewise.
	* c-c++-common/cpp/va-opt-pedantic.c: Likewise.
	* c-c++-common/cpp/Wheader-guard-2.c: Likewise.
	* c-c++-common/cpp/Wheader-guard-3.c: Likewise.
	* c-c++-common/cpp/Winvalid-utf8-1.c: Likewise.
	* c-c++-common/cpp/Winvalid-utf8-2.c: Likewise.
	* c-c++-common/cpp/Winvalid-utf8-3.c: Likewise.
	* c-c++-common/diagnostic-format-sarif-file-bad-utf8-pr109098-1.c:
	Likewise.
	* c-c++-common/diagnostic-format-sarif-file-bad-utf8-pr109098-3.c:
	Likewise.
	* c-c++-common/pr68833-3.c: Likewise.
	* c-c++-common/raw-string-directive-1.c: Likewise.
	* gcc.dg/analyzer/named-constants-Wunused-macros.c: Likewise.
	* gcc.dg/binary-constants-4.c: Likewise.
	* gcc.dg/builtin-redefine.c: Likewise.
	* gcc.dg/cpp/19951025-1.c: Likewise.
	* gcc.dg/cpp/c11-warning-1.c: Likewise.
	* gcc.dg/cpp/c11-warning-2.c: Likewise.
	* gcc.dg/cpp/c11-warning-3.c: Likewise.
	* gcc.dg/cpp/c23-elifdef-2.c: Likewise.
	* gcc.dg/cpp/c23-warning-2.c: Likewise.
	* gcc.dg/cpp/embed-2.c: Likewise.
	* gcc.dg/cpp/embed-3.c: Likewise.
	* gcc.dg/cpp/embed-4.c: Likewise.
	* gcc.dg/cpp/expr.c: Likewise.
	* gcc.dg/cpp/gnu11-elifdef-2.c: Likewise.
	* gcc.dg/cpp/gnu11-elifdef-3.c: Likewise.
	* gcc.dg/cpp/gnu11-elifdef-4.c: Likewise.
	* gcc.dg/cpp/gnu11-warning-1.c: Likewise.
	* gcc.dg/cpp/gnu11-warning-2.c: Likewise.
	* gcc.dg/cpp/gnu11-warning-3.c: Likewise.
	* gcc.dg/cpp/gnu23-warning-2.c: Likewise.
	* gcc.dg/cpp/include6.c: Likewise.
	* gcc.dg/cpp/pr35322.c: Likewise.
	* gcc.dg/cpp/tr-warn6.c: Likewise.
	* gcc.dg/cpp/undef2.c: Likewise.
	* gcc.dg/cpp/warn-comments.c: Likewise.
	* gcc.dg/cpp/warn-comments-2.c: Likewise.
	* gcc.dg/cpp/warn-comments-3.c: Likewise.
	* gcc.dg/cpp/warn-cxx-compat.c: Likewise.
	* gcc.dg/cpp/warn-cxx-compat-2.c: Likewise.
	* gcc.dg/cpp/warn-deprecated.c: Likewise.
	* gcc.dg/cpp/warn-deprecated-2.c: Likewise.
	* gcc.dg/cpp/warn-long-long.c: Likewise.
	* gcc.dg/cpp/warn-long-long-2.c: Likewise.
	* gcc.dg/cpp/warn-normalized-1.c: Likewise.
	* gcc.dg/cpp/warn-normalized-2.c: Likewise.
	* gcc.dg/cpp/warn-normalized-3.c: Likewise.
	* gcc.dg/cpp/warn-normalized-4-bytes.c: Likewise.
	* gcc.dg/cpp/warn-normalized-4-unicode.c: Likewise.
	* gcc.dg/cpp/warn-redefined.c: Likewise.
	* gcc.dg/cpp/warn-redefined-2.c: Likewise.
	* gcc.dg/cpp/warn-traditional.c: Likewise.
	* gcc.dg/cpp/warn-traditional-2.c: Likewise.
	* gcc.dg/cpp/warn-trigraphs-1.c: Likewise.
	* gcc.dg/cpp/warn-trigraphs-2.c: Likewise.
	* gcc.dg/cpp/warn-trigraphs-3.c: Likewise.
	* gcc.dg/cpp/warn-trigraphs-4.c: Likewise.
	* gcc.dg/cpp/warn-undef.c: Likewise.
	* gcc.dg/cpp/warn-undef-2.c: Likewise.
	* gcc.dg/cpp/warn-unused-macros.c: Likewise.
	* gcc.dg/cpp/warn-unused-macros-2.c: Likewise.
	* gcc.dg/pch/counter-2.c: Likewise.
	* g++.dg/cpp0x/udlit-error1.C: Likewise.
	* g++.dg/cpp23/named-universal-char-escape1.C: Likewise.
	* g++.dg/cpp23/named-universal-char-escape2.C: Likewise.
	* g++.dg/cpp23/Winvalid-utf8-1.C: Likewise.
	* g++.dg/cpp23/Winvalid-utf8-2.C: Likewise.
	* g++.dg/cpp23/Winvalid-utf8-3.C: Likewise.
	* g++.dg/cpp23/Winvalid-utf8-4.C: Likewise.
	* g++.dg/cpp23/Winvalid-utf8-5.C: Likewise.
	* g++.dg/cpp23/Winvalid-utf8-6.C: Likewise.
	* g++.dg/cpp23/Winvalid-utf8-7.C: Likewise.
	* g++.dg/cpp23/Winvalid-utf8-8.C: Likewise.
	* g++.dg/cpp23/Winvalid-utf8-9.C: Likewise.
	* g++.dg/cpp23/Winvalid-utf8-10.C: Likewise.
	* g++.dg/cpp23/Winvalid-utf8-11.C: Likewise.
	* g++.dg/cpp23/Winvalid-utf8-12.C: Likewise.
	* g++.dg/cpp/elifdef-3.C: Likewise.
	* g++.dg/cpp/elifdef-5.C: Likewise.
	* g++.dg/cpp/elifdef-6.C: Likewise.
	* g++.dg/cpp/elifdef-7.C: Likewise.
	* g++.dg/cpp/embed-1.C: Likewise.
	* g++.dg/cpp/embed-2.C: Likewise.
	* g++.dg/cpp/pedantic-errors.C: Likewise.
	* g++.dg/cpp/warning-1.C: Likewise.
	* g++.dg/cpp/warning-2.C: Likewise.
	* g++.dg/ext/bitint1.C: Likewise.
	* g++.dg/ext/bitint2.C: Likewise.

1 files changed, 40 insertions, 35 deletions

diff --git a/libcpp/expr.cc b/libcpp/expr.cc
index 089bf3e..b7772c9 100644
--- a/libcpp/expr.cc
+++ b/libcpp/expr.cc
@@ -678,10 +678,12 @@ cpp_classify_number (cpp_reader *pfile, const cpp_token *token,
     {
       if (radix == 2)
 	SYNTAX_ERROR2_AT (virtual_location,
-			  "invalid digit \"%c\" in binary constant", '0' + max_digit);
+			  "invalid digit %<%c%> in binary constant",
+			  '0' + max_digit);
       else
 	SYNTAX_ERROR2_AT (virtual_location,
-			  "invalid digit \"%c\" in octal constant", '0' + max_digit);
+			  "invalid digit %<%c%> in octal constant",
+			  '0' + max_digit);
     }
 
   if (float_flag != NOT_FLOAT)
@@ -689,7 +691,7 @@ cpp_classify_number (cpp_reader *pfile, const cpp_token *token,
       if (radix == 2)
 	{
 	  cpp_error_with_line (pfile, CPP_DL_ERROR, virtual_location, 0,
-			       "invalid prefix \"0b\" for floating constant");
+			       "invalid prefix %<0b%> for floating constant");
 	  return CPP_N_INVALID;
 	}
 
@@ -751,8 +753,8 @@ cpp_classify_number (cpp_reader *pfile, const cpp_token *token,
 	  else
 	    {
 	      cpp_error_with_line (pfile, CPP_DL_ERROR, virtual_location, 0,
-				   "invalid suffix \"%.*s\" on floating constant",
-				   (int) (limit - str), str);
+				   "invalid suffix %<%.*s%> on floating "
+				   "constant", (int) (limit - str), str);
 	      return CPP_N_INVALID;
 	    }
 	}
@@ -762,7 +764,7 @@ cpp_classify_number (cpp_reader *pfile, const cpp_token *token,
 	  && CPP_WTRADITIONAL (pfile)
 	  && ! cpp_sys_macro_p (pfile))
 	cpp_warning_with_line (pfile, CPP_W_TRADITIONAL, virtual_location, 0,
-			       "traditional C rejects the \"%.*s\" suffix",
+			       "traditional C rejects the %<%.*s%> suffix",
 			       (int) (limit - str), str);
 
       /* A suffix for double is a GCC extension via decimal float support.
@@ -777,8 +779,8 @@ cpp_classify_number (cpp_reader *pfile, const cpp_token *token,
       if ((result & CPP_N_DFLOAT) && radix != 10)
         {
           cpp_error_with_line (pfile, CPP_DL_ERROR, virtual_location, 0,
-			       "invalid suffix \"%.*s\" with hexadecimal floating constant",
-			       (int) (limit - str), str);
+			       "invalid suffix %<%.*s%> with hexadecimal "
+			       "floating constant", (int) (limit - str), str);
           return CPP_N_INVALID;
         }
 
@@ -791,11 +793,12 @@ cpp_classify_number (cpp_reader *pfile, const cpp_token *token,
 	  if (!CPP_OPTION (pfile, dfp_constants))
 	    cpp_pedwarning_with_line
 	      (pfile, CPP_W_PEDANTIC, virtual_location, 0,
-	       "decimal float constants are a C23 feature");
+	       "decimal floating constants are a C23 feature");
 	  else if (CPP_OPTION (pfile, cpp_warn_c11_c23_compat) > 0)
 	    cpp_warning_with_line (pfile, CPP_W_C11_C23_COMPAT,
 				   virtual_location, 0,
-				   "decimal float constants are a C23 feature");
+				   "decimal floating constants are a C23 "
+				   "feature");
 	}
 
       result |= CPP_N_FLOATING;
@@ -814,8 +817,8 @@ cpp_classify_number (cpp_reader *pfile, const cpp_token *token,
 	  else
 	    {
 	      cpp_error_with_line (pfile, CPP_DL_ERROR, virtual_location, 0,
-				   "invalid suffix \"%.*s\" on integer constant",
-				   (int) (limit - str), str);
+				   "invalid suffix %<%.*s%> on integer "
+				   "constant", (int) (limit - str), str);
 	      return CPP_N_INVALID;
 	    }
 	}
@@ -831,7 +834,7 @@ cpp_classify_number (cpp_reader *pfile, const cpp_token *token,
 	  if (u_or_i || large)
 	    cpp_warning_with_line (pfile, large ? CPP_W_LONG_LONG : CPP_W_TRADITIONAL,
 				   virtual_location, 0,
-				   "traditional C rejects the \"%.*s\" suffix",
+				   "traditional C rejects the %<%.*s%> suffix",
 				   (int) (limit - str), str);
 	}
 
@@ -853,9 +856,10 @@ cpp_classify_number (cpp_reader *pfile, const cpp_token *token,
       if ((result & CPP_N_SIZE_T) == CPP_N_SIZE_T
 	  && !CPP_OPTION (pfile, size_t_literals))
        {
-	  const char *message = (result & CPP_N_UNSIGNED) == CPP_N_UNSIGNED
-				? N_("use of C++23 %<size_t%> integer constant")
-				: N_("use of C++23 %<make_signed_t<size_t>%> integer constant");
+	  const char *message
+	    = (result & CPP_N_UNSIGNED) == CPP_N_UNSIGNED
+	      ? N_("use of C++23 %<size_t%> integer constant")
+	      : N_("use of C++23 %<make_signed_t<size_t>%> integer constant");
 	  cpp_warning_with_line (pfile, CPP_W_SIZE_T_LITERALS,
 				 virtual_location, 0, message);
        }
@@ -1118,7 +1122,7 @@ parse_defined (cpp_reader *pfile)
   cpp_context *initial_context = pfile->context;
 
   if (pfile->state.in_directive == 3)
-    cpp_error (pfile, CPP_DL_ERROR, "'defined' in #embed parameter");
+    cpp_error (pfile, CPP_DL_ERROR, "%<defined%> in %<#embed%> parameter");
 
   /* Don't expand macros.  */
   pfile->state.prevent_expansion++;
@@ -1135,14 +1139,14 @@ parse_defined (cpp_reader *pfile)
       node = token->val.node.node;
       if (paren && cpp_get_token (pfile)->type != CPP_CLOSE_PAREN)
 	{
-	  cpp_error (pfile, CPP_DL_ERROR, "missing ')' after \"defined\"");
+	  cpp_error (pfile, CPP_DL_ERROR, "missing %<)%> after %<defined%>");
 	  node = 0;
 	}
     }
   else
     {
       cpp_error (pfile, CPP_DL_ERROR,
-		 "operator \"defined\" requires an identifier");
+		 "operator %<defined%> requires an identifier");
       if (token->flags & NAMED_OP)
 	{
 	  cpp_token op;
@@ -1150,7 +1154,7 @@ parse_defined (cpp_reader *pfile)
 	  op.flags = 0;
 	  op.type = token->type;
 	  cpp_error (pfile, CPP_DL_ERROR,
-		     "(\"%s\" is an alternative token for \"%s\" in C++)",
+		     "(%qs is an alternative token for %qs in C++)",
 		     cpp_token_as_text (pfile, token),
 		     cpp_token_as_text (pfile, &op));
 	}
@@ -1163,7 +1167,7 @@ parse_defined (cpp_reader *pfile)
 	   || initial_context != &pfile->base_context)
 	  && CPP_OPTION (pfile, warn_expansion_to_defined))
         cpp_pedwarning (pfile, CPP_W_EXPANSION_TO_DEFINED,
-		        "this use of \"defined\" may not be portable");
+		        "this use of %<defined%> may not be portable");
       is_defined = _cpp_defined_macro_p (node);
       if (!_cpp_maybe_notify_macro_use (pfile, node, token->src_loc))
 	/* It wasn't a macro after all.  */
@@ -1268,7 +1272,7 @@ eval_token (cpp_reader *pfile, const cpp_token *token,
 	  result.low = 0;
 	  if (CPP_OPTION (pfile, warn_undef) && !pfile->state.skip_eval)
 	    cpp_warning_with_line (pfile, CPP_W_UNDEF, virtual_location, 0,
-				   "\"%s\" is not defined, evaluates to 0",
+				   "%qs is not defined, evaluates to %<0%>",
 				   NODE_NAME (token->val.node.node));
 	}
       break;
@@ -1431,7 +1435,7 @@ _cpp_parse_expr (cpp_reader *pfile, const char *dir,
 	case CPP_HASH:
 	  if (!want_value)
 	    SYNTAX_ERROR2_AT (op.loc,
-			      "missing binary operator before token \"%s\"",
+			      "missing binary operator before token %qs",
 			      cpp_token_as_text (pfile, op.token));
 	  want_value = false;
 	  top->value = eval_token (pfile, op.token, op.loc);
@@ -1456,7 +1460,8 @@ _cpp_parse_expr (cpp_reader *pfile, const char *dir,
 	default:
 	  if ((int) op.op <= (int) CPP_EQ || (int) op.op >= (int) CPP_PLUS_EQ)
 	    SYNTAX_ERROR2_AT (op.loc,
-			      "token \"%s\" is not valid in preprocessor expressions",
+			      "token %qs is not valid in preprocessor "
+			      "expressions",
 			      cpp_token_as_text (pfile, op.token));
 	  break;
 	}
@@ -1466,7 +1471,7 @@ _cpp_parse_expr (cpp_reader *pfile, const char *dir,
 	{
 	  if (!want_value)
 	    SYNTAX_ERROR2_AT (op.loc,
-			      "missing binary operator before token \"%s\"",
+			      "missing binary operator before token %qs",
 			      cpp_token_as_text (pfile, op.token));
 	}
       else if (want_value)
@@ -1475,7 +1480,7 @@ _cpp_parse_expr (cpp_reader *pfile, const char *dir,
 	     Try to emit a specific diagnostic.  */
 	  if (op.op == CPP_CLOSE_PAREN && top->op == CPP_OPEN_PAREN)
 	    SYNTAX_ERROR_AT (op.loc,
-			     "missing expression between '(' and ')'");
+			     "missing expression between %<(%> and %<)%>");
 
 	  if (op.op == CPP_EOF && top->op == CPP_EOF)
  	    SYNTAX_ERROR2_AT (op.loc,
@@ -1483,13 +1488,13 @@ _cpp_parse_expr (cpp_reader *pfile, const char *dir,
 
  	  if (top->op != CPP_EOF && top->op != CPP_OPEN_PAREN)
  	    SYNTAX_ERROR2_AT (op.loc,
-			      "operator '%s' has no right operand",
+			      "operator %qs has no right operand",
 			      cpp_token_as_text (pfile, top->token));
 	  else if (op.op == CPP_CLOSE_PAREN || op.op == CPP_EOF)
 	    /* Complain about missing paren during reduction.  */;
 	  else
 	    SYNTAX_ERROR2_AT (op.loc,
-			      "operator '%s' has no left operand",
+			      "operator %qs has no left operand",
 			      cpp_token_as_text (pfile, op.token));
 	}
 
@@ -1518,7 +1523,7 @@ _cpp_parse_expr (cpp_reader *pfile, const char *dir,
 	case CPP_COLON:
 	  if (top->op != CPP_QUERY)
 	    SYNTAX_ERROR_AT (op.loc,
-			     " ':' without preceding '?'");
+			     " %<:%> without preceding %<?%>");
 	  if (!num_zerop (top[-1].value)) /* Was '?' condition true?  */
 	    pfile->state.skip_eval++;
 	  else
@@ -1687,7 +1692,7 @@ reduce (cpp_reader *pfile, struct op *top, enum cpp_ttype op)
 	    {
 	      cpp_error_with_line (pfile, CPP_DL_ERROR, 
 				   top->token->src_loc,
-				   0, "missing ')' in expression");
+				   0, "missing %<)%> in expression");
 	      return 0;
 	    }
 	  top--;
@@ -1716,7 +1721,7 @@ reduce (cpp_reader *pfile, struct op *top, enum cpp_ttype op)
 	  /* COMMA and COLON should not reduce a QUERY operator.  */
 	  if (op == CPP_COMMA || op == CPP_COLON)
 	    return top;
-	  cpp_error (pfile, CPP_DL_ERROR, "'?' without following ':'");
+	  cpp_error (pfile, CPP_DL_ERROR, "%<?%> without following %<:%>");
 	  return 0;
 
 	default:
@@ -1731,7 +1736,7 @@ reduce (cpp_reader *pfile, struct op *top, enum cpp_ttype op)
 
   if (op == CPP_CLOSE_PAREN)
     {
-      cpp_error (pfile, CPP_DL_ERROR, "missing '(' in expression");
+      cpp_error (pfile, CPP_DL_ERROR, "missing %<(%> in expression");
       return 0;
     }
 
@@ -1763,12 +1768,12 @@ check_promotion (cpp_reader *pfile, const struct op *op)
     {
       if (!num_positive (op[-1].value, CPP_OPTION (pfile, precision)))
 	cpp_error_with_line (pfile, CPP_DL_WARNING, op[-1].loc, 0,
-			     "the left operand of \"%s\" changes sign when promoted",
-			     cpp_token_as_text (pfile, op->token));
+			     "the left operand of %qs changes sign when "
+			     "promoted", cpp_token_as_text (pfile, op->token));
     }
   else if (!num_positive (op->value, CPP_OPTION (pfile, precision)))
     cpp_error_with_line (pfile, CPP_DL_WARNING, op->loc, 0,
-	       "the right operand of \"%s\" changes sign when promoted",
+	       "the right operand of %qs changes sign when promoted",
 	       cpp_token_as_text (pfile, op->token));
 }