auto generate cpp_reason to gcc OPT_W table

Index: gcc/doc/options.texi
===================================================================
--- gcc/doc/options.texi	(revision 214904)
+++ gcc/doc/options.texi	(working copy)
@@ -486,6 +486,11 @@  to determine if a precompiled header fil
 @item CPP(@var{var})
 The state of this option should be kept in sync with the preprocessor
 option @var{var}.  If this property is set, then properties @code{Var}
 and @code{Init} must be set as well.
 
+@item CppReason(@var{CPP_W_Enum})
+This warning option corresponds to @code{cpplib.h} warning reason code
+@var{CPP_W_Enum}.  This should only be used for warning options of the
+C-family front-ends.
+
 @end table
Index: gcc/c-family/c.opt
===================================================================
--- gcc/c-family/c.opt	(revision 214904)
+++ gcc/c-family/c.opt	(working copy)
@@ -290,23 +290,23 @@  Warn about casting functions to incompat
 Wbool-compare
 C ObjC C++ ObjC++ Var(warn_bool_compare) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
 Warn about boolean expression compared with an integer value different from true/false
 
 Wbuiltin-macro-redefined
-C ObjC C++ ObjC++ CPP(warn_builtin_macro_redefined) Var(cpp_warn_builtin_macro_redefined) Init(1) Warning
+C ObjC C++ ObjC++ CPP(warn_builtin_macro_redefined) CppReason(CPP_W_BUILTIN_MACRO_REDEFINED) Var(cpp_warn_builtin_macro_redefined) Init(1) Warning
 Warn when a built-in preprocessor macro is undefined or redefined
 
 Wc90-c99-compat
-C ObjC CPP(cpp_warn_c90_c99_compat) Var(warn_c90_c99_compat) Init(-1) Warning
+C ObjC CPP(cpp_warn_c90_c99_compat) CppReason(CPP_W_C90_C99_COMPAT) Var(warn_c90_c99_compat) Init(-1) Warning
 Warn about features not present in ISO C90, but present in ISO C99
 
 Wc99-c11-compat
 C ObjC Var(warn_c99_c11_compat) Init(-1) Warning
 Warn about features not present in ISO C99, but present in ISO C11
 
 Wc++-compat
-C ObjC Var(warn_cxx_compat) CPP(warn_cxx_operator_names) Init(0) Warning
+C ObjC Var(warn_cxx_compat) CPP(warn_cxx_operator_names) CppReason(CPP_W_CXX_OPERATOR_NAMES) Init(0) Warning
 Warn about C constructs that are not in the common subset of C and C++
 
 Wc++0x-compat
 C++ ObjC++ Var(warn_cxx0x_compat) Warning LangEnabledBy(C++ ObjC++,Wall)
 Deprecated in favor of -Wc++11-compat
@@ -326,11 +326,11 @@  Warn about subscripts whose type is \"ch
 Wclobbered
 C ObjC C++ ObjC++ Var(warn_clobbered) Warning EnabledBy(Wextra)
 Warn about variables that might be changed by \"longjmp\" or \"vfork\"
 
 Wcomment
-C ObjC C++ ObjC++ CPP(warn_comments) Var(cpp_warn_comment) Init(0) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
+C ObjC C++ ObjC++ CPP(warn_comments) CppReason(CPP_W_COMMENTS) Var(cpp_warn_comment) Init(0) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
 Warn about possibly nested block comments, and C++ comments spanning more than one physical line
 
 Wcomments
 C ObjC C++ ObjC++ Warning Alias(Wcomment)
 Synonym for -Wcomment
@@ -345,14 +345,22 @@  Warn for implicit type conversions that
 
 Wconversion-null
 C++ ObjC++ Var(warn_conversion_null) Init(1) Warning
 Warn for converting NULL from/to a non-pointer type
 
+Wcpp
+C ObjC C++ ObjC++ CppReason(CPP_W_WARNING_DIRECTIVE)
+; Documented in common.opt
+
 Wctor-dtor-privacy
 C++ ObjC++ Var(warn_ctor_dtor_privacy) Warning
 Warn when all constructors and destructors are private
 
+Wdate-time
+C ObjC C++ ObjC++ CPP(warn_date_time) CppReason(CPP_W_DATE_TIME) Var(cpp_warn_date_time) Init(0) Warning
+Warn about __TIME__, __DATE__ and __TIMESTAMP__ usage
+
 Wdeclaration-after-statement
 C ObjC Var(warn_declaration_after_statement) Init(-1) Warning
 Warn when a declaration is found after a statement
 
 Wdelete-incomplete
@@ -366,11 +374,11 @@  Warn about deleting polymorphic objects
 Wdelete-non-virtual-dtor
 LangEnabledBy(C++ ObjC++,Weffc++)
 ;
 
 Wdeprecated
-C C++ ObjC ObjC++ CPP(cpp_warn_deprecated) Var(warn_deprecated) Init(1) Warning
+C C++ ObjC ObjC++ CPP(cpp_warn_deprecated) CppReason(CPP_W_DEPRECATED) Var(warn_deprecated) Init(1) Warning
 Warn if a deprecated compiler feature, class, method, or field is used
 
 Wdesignated-init
 C ObjC Var(warn_designated_init) Init(1) Warning
 Warn about positional initialization of structs requiring designated initializers
@@ -390,11 +398,11 @@  Warn about violations of Effective C++ s
 Wempty-body
 C ObjC C++ ObjC++ Var(warn_empty_body) Warning EnabledBy(Wextra)
 Warn about an empty body in an if or else statement
 
 Wendif-labels
-C ObjC C++ ObjC++ CPP(warn_endif_labels) Var(cpp_warn_endif_labels) Init(1) Warning LangEnabledBy(C ObjC C++ ObjC++,Wpedantic)
+C ObjC C++ ObjC++ CPP(warn_endif_labels) CppReason(CPP_W_ENDIF_LABELS) Var(cpp_warn_endif_labels) Init(1) Warning LangEnabledBy(C ObjC C++ ObjC++,Wpedantic)
 Warn about stray tokens after #elif and #endif
 
 Wenum-compare
 C ObjC C++ ObjC++ Var(warn_enum_compare) Init(-1) Warning LangEnabledBy(C ObjC,Wall)
 Warn about comparison of different enum types
@@ -501,19 +509,19 @@  Warn when there is a cast to a pointer f
 Winvalid-offsetof
 C++ ObjC++ Var(warn_invalid_offsetof) Init(1) Warning
 Warn about invalid uses of the \"offsetof\" macro
 
 Winvalid-pch
-C ObjC C++ ObjC++ CPP(warn_invalid_pch) Var(cpp_warn_invalid_pch) Init(0) Warning
+C ObjC C++ ObjC++ CPP(warn_invalid_pch) CppReason(CPP_W_INVALID_PCH) Var(cpp_warn_invalid_pch) Init(0) Warning
 Warn about PCH files that are found but not used
 
 Wjump-misses-init
 C ObjC Var(warn_jump_misses_init) Warning LangEnabledby(C ObjC,Wc++-compat)
 Warn when a jump misses a variable initialization
 
 Wliteral-suffix
-C++ ObjC++ CPP(warn_literal_suffix) Var(cpp_warn_literal_suffix) Init(1) Warning
+C++ ObjC++ CPP(warn_literal_suffix) CppReason(CPP_W_LITERAL_SUFFIX) Var(cpp_warn_literal_suffix) Init(1) Warning
 Warn when a string or character literal is followed by a ud-suffix which does not begin with an underscore.
 
 Wlogical-op
 C ObjC C++ ObjC++ Var(warn_logical_op) Init(0) Warning 
 Warn when a logical operator is suspiciously always evaluating to true or false
@@ -521,11 +529,11 @@  Warn when a logical operator is suspicio
 Wlogical-not-parentheses
 C ObjC C++ ObjC++ Var(warn_logical_not_paren) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
 Warn when logical not is used on the left hand side operand of a comparison
 
 Wlong-long
-C ObjC C++ ObjC++ CPP(cpp_warn_long_long) Var(warn_long_long) Init(-1) Warning LangEnabledBy(C ObjC,Wc90-c99-compat)
+C ObjC C++ ObjC++ CPP(cpp_warn_long_long) CppReason(CPP_W_LONG_LONG) Var(warn_long_long) Init(-1) Warning LangEnabledBy(C ObjC,Wc90-c99-compat)
 Do not warn about using \"long long\" when -pedantic
 
 Wmain
 C ObjC C++ ObjC++ Var(warn_main) Init(-1) Warning LangEnabledBy(C ObjC,Wall, 2, 0)
 Warn about suspicious declarations of \"main\"
@@ -581,11 +589,11 @@  Warn about switches with boolean control
 Wmissing-format-attribute
 C ObjC C++ ObjC++ Alias(Wsuggest-attribute=format)
 ;
 
 Wmissing-include-dirs
-C ObjC C++ ObjC++ CPP(warn_missing_include_dirs) Var(cpp_warn_missing_include_dirs) Init(0) Warning
+C ObjC C++ ObjC++ CPP(warn_missing_include_dirs) CppReason(CPP_W_MISSING_INCLUDE_DIRS) Var(cpp_warn_missing_include_dirs) Init(0) Warning
 Warn about user-specified include directories that do not exist
 
 Wmissing-parameter-type
 C ObjC Var(warn_missing_parameter_type) Warning EnabledBy(Wextra)
 Warn about function parameters declared without a type specifier in K&R-style functions
@@ -596,11 +604,11 @@  Warn about global functions without prot
 
 Wmudflap
 C ObjC C++ ObjC++ Ignore Warn(switch %qs is no longer supported)
 
 Wmultichar
-C ObjC C++ ObjC++ CPP(warn_multichar) Var(cpp_warn_multichar) Init(0) Warning
+C ObjC C++ ObjC++ CPP(warn_multichar) CppReason(CPP_W_MULTICHAR) Var(cpp_warn_multichar) Init(0) Warning
 Warn about use of multi-character character constants
 
 Wnarrowing
 C ObjC C++ ObjC++ Warning Var(warn_narrowing) Init(-1) LangEnabledBy(C++ ObjC++,Wall)
 Warn about narrowing conversions within { } that are ill-formed in C++11
@@ -631,12 +639,12 @@  Warn about NULL being passed to argument
 
 Wnonnull
 C ObjC C++ ObjC++ LangEnabledBy(C ObjC C++ ObjC++,Wall)
 ;
 
 Wnormalized
 C ObjC C++ ObjC++ Alias(Wnormalized=,nfc,none)
 ;
 
 Wnormalized=
-C ObjC C++ ObjC++ RejectNegative Joined Warning CPP(warn_normalize) Init(normalized_C) Var(cpp_warn_normalize) Enum(cpp_normalize_level)
+C ObjC C++ ObjC++ RejectNegative Joined Warning CPP(warn_normalize) CppReason(CPP_W_NORMALIZE) Init(normalized_C) Var(cpp_warn_normalize) Enum(cpp_normalize_level)
 -Wnormalized=<none|id|nfc|nfkc>	Warn about non-normalised Unicode strings
@@ -672,11 +703,11 @@  Warn about packed bit-fields whose offse
 Wparentheses
 C ObjC C++ ObjC++ Var(warn_parentheses) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
 Warn about possibly missing parentheses
 
 Wpedantic
-C ObjC C++ ObjC++ CPP(cpp_pedantic) Warning
+C ObjC C++ ObjC++ CPP(cpp_pedantic) CppReason(CPP_W_PEDANTIC) Warning
 ; Documented in common.opt
 
 Wpmf-conversions
 C++ ObjC++ Var(warn_pmf2ptr) Init(1) Warning
 Warn when converting the type of pointers to member functions
@@ -699,14 +730,10 @@  Warn when a pointer is cast to an intege
 
 Wpragmas
 C ObjC C++ ObjC++ Var(warn_pragmas) Init(1) Warning
 Warn about misuses of pragmas
 
-Wdate-time
-C ObjC C++ ObjC++ CPP(warn_date_time) Var(cpp_warn_date_time) Init(0) Warning
-Warn about __TIME__, __DATE__ and __TIMESTAMP__ usage
-
 Wproperty-assign-default
 ObjC ObjC++ Var(warn_property_assign_default) Init(1) Warning
 Warn if a property for an Objective-C object has no assign semantics specified
 
 Wprotocol
@@ -784,27 +811,27 @@  Deprecated.  This switch has no effect
 Wsystem-headers
 C ObjC C++ ObjC++ Warning
 ; Documented in common.opt
 
 Wtraditional
-C ObjC CPP(cpp_warn_traditional) Var(warn_traditional) Init(0) Warning
+C ObjC CPP(cpp_warn_traditional) CppReason(CPP_W_TRADITIONAL) Var(warn_traditional) Init(0) Warning
 Warn about features not present in traditional C
 
 Wtraditional-conversion
 C ObjC Var(warn_traditional_conversion) Warning
 Warn of prototypes causing type conversions different from what would happen in the absence of prototype
 
 Wtrigraphs
-C ObjC C++ ObjC++ CPP(warn_trigraphs) Var(cpp_warn_trigraphs) Init(2) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
+C ObjC C++ ObjC++ CPP(warn_trigraphs) CppReason(CPP_W_TRIGRAPHS) Var(cpp_warn_trigraphs) Init(2) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
 Warn if trigraphs are encountered that might affect the meaning of the program
 
 Wundeclared-selector
 ObjC ObjC++ Var(warn_undeclared_selector) Warning
 Warn about @selector()s without previously declared methods
 
 Wundef
-C ObjC C++ ObjC++ CPP(warn_undef) Var(cpp_warn_undef) Init(0) Warning
+C ObjC C++ ObjC++ CPP(warn_undef) CppReason(CPP_W_UNDEF) Var(cpp_warn_undef) Init(0) Warning
 Warn if an undefined macro is used in an #if directive
 
 Wuninitialized
 C ObjC C++ ObjC++ LangEnabledBy(C ObjC C++ ObjC++,Wall)
 ;
@@ -828,19 +855,19 @@  C ObjC C++ ObjC++ LangEnabledBy(C ObjC C
 Wunused-local-typedefs
 C ObjC C++ ObjC++ Var(warn_unused_local_typedefs) Warning EnabledBy(Wunused)
 Warn when typedefs locally defined in a function are not used
 
 Wunused-macros
-C ObjC C++ ObjC++ Var(cpp_warn_unused_macros) Warning
+C ObjC C++ ObjC++ CppReason(CPP_W_UNUSED_MACROS) Var(cpp_warn_unused_macros) Warning
 Warn about macros defined in the main file that are not used
 
 Wunused-result
 C ObjC C++ ObjC++ Var(warn_unused_result) Init(1) Warning
 Warn if a caller of a function, marked with attribute warn_unused_result, does not use its return value
 
 Wvariadic-macros
-C ObjC C++ ObjC++ CPP(warn_variadic_macros) Var(cpp_warn_variadic_macros) Init(0) Warning LangEnabledBy(C ObjC C++ ObjC++,Wpedantic)
+C ObjC C++ ObjC++ CPP(warn_variadic_macros) CppReason(CPP_W_VARIADIC_MACROS) Var(cpp_warn_variadic_macros) Init(0) Warning LangEnabledBy(C ObjC C++ ObjC++,Wpedantic)
 Warn about using variadic macros
 
 Wvariadic-macros
 LangEnabledBy(C ObjC C++ ObjC++,Wtraditional)
 ;
Index: gcc/c-family/c-common.c
===================================================================
--- gcc/c-family/c-common.c	(revision 214904)
+++ gcc/c-family/c-common.c	(working copy)
@@ -18,10 +18,11 @@  along with GCC; see the file COPYING3.
 <http://www.gnu.org/licenses/>.  */
 
 #include "config.h"
 #include "system.h"
 #include "coretypes.h"
+#include "c-common.h"
 #include "tm.h"
 #include "intl.h"
 #include "tree.h"
 #include "fold-const.h"
 #include "stor-layout.h"
@@ -30,11 +31,10 @@  along with GCC; see the file COPYING3.
 #include "attribs.h"
 #include "varasm.h"
 #include "trans-mem.h"
 #include "flags.h"
 #include "c-pragma.h"
-#include "c-common.h"
 #include "c-objc.h"
 #include "tm_p.h"
 #include "obstack.h"
 #include "cpplib.h"
 #include "target.h"
@@ -9664,51 +9664,19 @@  c_parse_error (const char *gmsgid, enum
       free (message);
     }
 #undef catenate_messages
 }
 
-/* Mapping for cpp message reasons to the options that enable them.  */
-
-struct reason_option_codes_t
-{
-  const int reason;		/* cpplib message reason.  */
-  const int option_code;	/* gcc option that controls this message.  */
-};
-
-static const struct reason_option_codes_t option_codes[] = {
-  {CPP_W_BUILTIN_MACRO_REDEFINED,	OPT_Wbuiltin_macro_redefined},
-  {CPP_W_C90_C99_COMPAT,                OPT_Wc90_c99_compat},
-  {CPP_W_COMMENTS,			OPT_Wcomment},
-  {CPP_W_CXX_OPERATOR_NAMES,		OPT_Wc___compat},
-  {CPP_W_DATE_TIME,			OPT_Wdate_time},
-  {CPP_W_DEPRECATED,			OPT_Wdeprecated},
-  {CPP_W_ENDIF_LABELS,			OPT_Wendif_labels},
-  {CPP_W_INVALID_PCH,			OPT_Winvalid_pch},
-  {CPP_W_LITERAL_SUFFIX,		OPT_Wliteral_suffix},
-  {CPP_W_LONG_LONG,			OPT_Wlong_long},
-  {CPP_W_MISSING_INCLUDE_DIRS,          OPT_Wmissing_include_dirs},
-  {CPP_W_MULTICHAR,			OPT_Wmultichar},
-  {CPP_W_NORMALIZE,			OPT_Wnormalized_},
-  {CPP_W_PEDANTIC,                      OPT_Wpedantic},
-  {CPP_W_TRADITIONAL,			OPT_Wtraditional},
-  {CPP_W_TRIGRAPHS,			OPT_Wtrigraphs},
-  {CPP_W_UNDEF,				OPT_Wundef},
-  {CPP_W_UNUSED_MACROS,			OPT_Wunused_macros},
-  {CPP_W_VARIADIC_MACROS,		OPT_Wvariadic_macros},
-  {CPP_W_WARNING_DIRECTIVE,		OPT_Wcpp},
-  {CPP_W_NONE,				0}
-};
-
 /* Return the gcc option code associated with the reason for a cpp
    message, or 0 if none.  */
 
 static int
 c_option_controlling_cpp_error (int reason)
 {
-  const struct reason_option_codes_t *entry;
+  const struct cpp_reason_option_codes_t *entry;
 
-  for (entry = option_codes; entry->reason != CPP_W_NONE; entry++)
+  for (entry = cpp_reason_option_codes; entry->reason != CPP_W_NONE; entry++)
     {
       if (entry->reason == reason)
 	return entry->option_code;
     }
   return 0;
Index: gcc/opth-gen.awk
===================================================================
--- gcc/opth-gen.awk	(revision 214904)
+++ gcc/opth-gen.awk	(working copy)
@@ -477,7 +477,34 @@  print "  OPT_SPECIAL_unknown,"
 print "  OPT_SPECIAL_ignore,"
 print "  OPT_SPECIAL_program_name,"
 print "  OPT_SPECIAL_input_file"
 print "};"
 print ""
+print "#ifdef GCC_C_COMMON_H"
+print "/* Mapping from cpp message reasons to the options that enable them.  */"
+print "#include <cpplib.h>"
+print "struct cpp_reason_option_codes_t"
+print "{"
+print "  const int reason;		/* cpplib message reason.  */"
+print "  const int option_code;	/* gcc option that controls this message.  */"
+print "};"
+print ""
+print "static const struct cpp_reason_option_codes_t cpp_reason_option_codes[] = {"
+for (i = 0; i < n_opts; i++) {
+    # With identical flags, pick only the last one.  The
+    # earlier loop ensured that it has all flags merged,
+    # and a nonempty help text if one of the texts was nonempty.
+    while( i + 1 != n_opts && opts[i] == opts[i + 1] ) {
+        i++;
+    }
+    cpp_reason = nth_arg(0, opt_args("CppReason", flags[i]));
+    if (cpp_reason != "") {
+        cpp_reason = cpp_reason ",";
+        printf("  {%-40s %s},\n", cpp_reason, opt_enum(opts[i]))
+    }
+}
+printf("  {%-40s 0},\n", "CPP_W_NONE,")
+print "};"
+print "#endif"
+print ""
 print "#endif /* OPTIONS_H */"
 }