C++ Module options

This adds the C++ module options, and wires them into lang-specs.  The
options are not connected to any machinery.  The options! They do
nothing!

	gcc/c-family/
	* c-opts.c (c_common_init_options): Ask for module dependencies.
	(c_common_handle_option): Handle -Mmodules -Mno-modules.
	* c-pch.c (c_common_valid_pch): ... does not play with C++
	modules.
	* c.opt (Mmodules, Mno-modules): New preprocessor dependency
	options.
	(fmodules-ts, fmodule-header, fmodule-implicit-inline)
	(fmodule-only, fmodule-mapper, fmodule-lazy)
	(fmodule-version-ignore, Winvalid-imported-macros)
	(flang-info-include-translate, flang-info-include-translate-not):
	New options
	gcc/cp/
	* lang-specs.h: Add module-related options.

3 files changed, 76 insertions, 0 deletions

diff --git a/gcc/c-family/c-opts.c b/gcc/c-family/c-opts.c
index 77844d7..59cabd1 100644
--- a/gcc/c-family/c-opts.c
+++ b/gcc/c-family/c-opts.c
@@ -234,6 +234,7 @@ c_common_init_options (unsigned int decoded_options_count,
   cpp_opts = cpp_get_options (parse_in);
   cpp_opts->dollars_in_ident = DOLLARS_IN_IDENTIFIERS;
   cpp_opts->objc = c_dialect_objc ();
+  cpp_opts->deps.modules = true;
 
   /* Reset to avoid warnings on internal definitions.  We set it just
      before passing on command-line options to cpplib.  */
@@ -367,6 +368,18 @@ c_common_handle_option (size_t scode, const char *arg, HOST_WIDE_INT value,
       cpp_opts->deps.phony_targets = true;
       break;
 
+    case OPT_Mmodules:
+      /* Do not set deps_seen, so the user can unconditionally turn
+	 this on or off.  */
+      cpp_opts->deps.modules = true;
+      break;
+
+    case OPT_Mno_modules:
+      /* Do not set deps_seen, so the user can unconditionally turn
+	 this on or off.  */
+      cpp_opts->deps.modules = false;
+      break;
+
     case OPT_MQ:
     case OPT_MT:
       deps_seen = true;
diff --git a/gcc/c-family/c-pch.c b/gcc/c-family/c-pch.c
index 9c0bd0b..fdeb860 100644
--- a/gcc/c-family/c-pch.c
+++ b/gcc/c-family/c-pch.c
@@ -206,6 +206,10 @@ c_common_valid_pch (cpp_reader *pfile, const char *name, int fd)
   /* Perform a quick test of whether this is a valid
      precompiled header for the current language.  */
 
+  /* C++ modules and PCH don't play together.  */
+  if (flag_modules)
+    return 2;
+
   sizeread = read (fd, ident, IDENT_LENGTH + 16);
   if (sizeread == -1)
     fatal_error (input_location, "cannot read %s: %m", name);
diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt
index 0532cb7..059f6c3 100644
--- a/gcc/c-family/c.opt
+++ b/gcc/c-family/c.opt
@@ -236,6 +236,14 @@ MMD
 C ObjC C++ ObjC++ NoDriverArg Separate MissingArgError(missing filename after %qs)
 Like -MD but ignore system header files.
 
+Mmodules
+C++
+Generate C++ Module dependency information.
+
+Mno-modules
+C++
+; undocumented
+
 MP
 C ObjC C++ ObjC++
 Generate phony targets for all headers.
@@ -1683,6 +1691,57 @@ flax-vector-conversions
 C ObjC C++ ObjC++ Var(flag_lax_vector_conversions)
 Allow implicit conversions between vectors with differing numbers of subparts and/or differing element types.
 
+fmodules-ts
+C++ ObjC++ Var(flag_modules) Integer Init(0)
+Enable C++ modules-ts (experimental).
+
+fno-modules
+C++ ObjC++ Undocumented RejectNegative Var(flag_modules,0) Integer
+;; undocumented
+
+fmodule-header
+C++ ObjC RejectNegative Var(flag_header_unit,0) Integer
+Enable C++ header module (experimental).
+
+fmodule-header=
+C++ ObjC++ Joined RejectNegative Undocumented
+
+fmodule-implicit-inline
+C++ ObjC++ Var(flag_module_implicit_inline,0) Integer
+Member functions defined within their class are inline in module purview.
+
+fmodule-only
+C++ ObjC RejectNegative Var(flag_module_only) Integer
+Only emit Compiled Module Interface.
+
+fmodule-mapper=
+C++ ObjC++ Joined RejectNegative MissingArgError(missing mapper)
+Mapper for module to CMI files.
+
+fmodule-lazy
+C++ ObjC++ Var(flag_module_lazy) Init(1)
+Enable lazy module importing.
+
+fmodule-version-ignore
+C++ ObjC Var(flag_module_version_ignore) Integer
+; undocumented, Very dangerous, but occasionally useful
+
+Winvalid-imported-macros
+C++ ObjC++ Var(warn_imported_macros)
+Warn about macros that have conflicting header units definitions.
+
+flang-info-include-translate
+C++ Var(note_include_translate_yes)
+Note #include directives translated to import declarations.
+
+flang-info-include-translate-not
+C++ Var(note_include_translate_no)
+Note #include directives not translated to import declarations, and not known to be textual.
+
+flang-info-include-translate=
+C++ Joined RejectNegative MissingArgError(missing header name)
+Note a #include translation of a specific header.
+
 fmax-include-depth=
 C ObjC C++ ObjC++ Joined RejectNegative UInteger
 fmax-include-depth=<number> Set the maximum depth of the nested #include.