c.opt: Add -fmodule-header.

gcc/c-family/
	* c.opt: Add -fmodule-header.
	gcc/cp/
	* lang-specs.h: Add legacy import options.
	* module.c (module_header_name): New.
	(init_module_processing): Default it.
	(handle_module_option): Set it.

From-SVN: r261862

ChangeLog.modules

@@ -1,5 +1,13 @@
 2018-06-21  Nathan Sidwell  <nathan@acm.org>
 
+	gcc/c-family/
+	* c.opt: Add -fmodule-header.
+	gcc/cp/
+	* lang-specs.h: Add legacy import options.
+	* module.c (module_header_name): New.
+	(init_module_processing): Default it.
+	(handle_module_option): Set it.
+
 	Use getaddrinfo, not gethostbyname2
 	gcc/
 	* configure.ac (HAVE_AF_INET6): Test for getaddrinfo.

gcc/c-family/c.opt

@@ -1532,6 +1532,14 @@ fno-modules
 C++ ObjC++ Driver Undocumented RejectNegative Var(flag_modules,0) Integer
 ;; undocumented
 
+fmodule-header
+C++ ObjC Driver Undocumented RejectNegative
+;; undocumented
+
+fmodule-header=
+C++ ObjC++ Driver Joined RejectNegative MissingArgError(missing header name)
+ATOM legacy import name
+
 fmodule-mapper=
 C++ ObjC++ Driver Joined RejectNegative MissingArgError(missing mapper)
 Mapper for module to BMI files

gcc/cp/lang-specs.h

@@ -40,29 +40,32 @@ along with GCC; see the file COPYING3.  If not see
   {".tcc", "@c++-header", 0, 0, 0},
   {".hh",  "@c++-header", 0, 0, 0},
   {"@c++-header",
-    "%{E|M|MM:cc1plus -E %(cpp_options) %2 %(cpp_debug_options)}\
-     %{!E:%{!M:%{!MM:\
-       %{save-temps*|no-integrated-cpp:cc1plus -E\
-		%(cpp_options) %2 -o %{save-temps*:%b.ii} %{!save-temps*:%g.ii} \n}\
-      cc1plus %{save-temps*|no-integrated-cpp:-fpreprocessed %{save-temps*:%b.ii} %{!save-temps*:%g.ii}}\
-	      %{!save-temps*:%{!no-integrated-cpp:%(cpp_unique_options)}}\
-	%(cc1_options) %2\
-	%{!fsyntax-only:%{!S:-o %g.s} \
-	    %{!fdump-ada-spec*:%{!o*:--output-pch=%i.gch}\
-			       %W{o*:--output-pch=%*}}%V}}}}",
+      "%{E|M|MM:cc1plus -E %(cpp_options) %2 %(cpp_debug_options)}"
+      "%{!E:%{!M:%{!MM:"
+      "   %{save-temps*|no-integrated-cpp:cc1plus -E"
+      "    %(cpp_options) %2 -o %{save-temps*:%b.ii} %{!save-temps*:%g.ii} \n}"
+      "   cc1plus %{save-temps*|no-integrated-cpp:-fpreprocessed"
+      "             %{save-temps*:%b.ii} %{!save-temps*:%g.ii}}"
+      "   %{!save-temps*:%{!no-integrated-cpp:%(cpp_unique_options)}}"
+      "   %(cc1_options) %2"
+      "   %{fmodules-atom:%{fmodule-header*:-fmodule-header}}"
+      "   %{!fsyntax-only:%{!S:-o %g.s}"
+      "     %{!fdump-ada-spec*:%{!fmodules-atom:"
+      "          %{!o*:--output-pch=%i.gch}%W{o*:--output-pch=%*}}%V}}}}}",
      CPLUSPLUS_CPP_SPEC, 0, 0},
   {"@c++",
-    "%{E|M|MM:cc1plus -E %{fmodule-prefix*} %(cpp_options) %2 %(cpp_debug_options)}\
-     %{!E:%{!M:%{!MM:\
-       %{save-temps*|no-integrated-cpp:cc1plus -E\
-		%(cpp_options) %2 -o %{save-temps*:%b.ii} %{!save-temps*:%g.ii} \n}\
-      cc1plus %{save-temps*|no-integrated-cpp:-fpreprocessed %{save-temps*:%b.ii} %{!save-temps*:%g.ii}}\
-	      %{!save-temps*:%{!no-integrated-cpp:%(cpp_unique_options)}}\
-	%(cc1_options) %2\
-       %{!fsyntax-only:%(invoke_as)}}}}",
-     CPLUSPLUS_CPP_SPEC, 0, 0},
+      "%{E|M|MM:cc1plus -E %(cpp_options) %2 %(cpp_debug_options)}"
+      "%{!E:%{!M:%{!MM:"
+      "   %{save-temps*|no-integrated-cpp:cc1plus -E"
+      "	   %(cpp_options) %2 -o %{save-temps*:%b.ii} %{!save-temps*:%g.ii} \n}"
+      "   cc1plus %{save-temps*|no-integrated-cpp:-fpreprocessed"
+      "             %{save-temps*:%b.ii} %{!save-temps*:%g.ii}}"
+      "   %{!save-temps*:%{!no-integrated-cpp:%(cpp_unique_options)}}"
+      "   %(cc1_options) %2"
+      "   %{!fsyntax-only:%(invoke_as)}}}}",
+      CPLUSPLUS_CPP_SPEC, 0, 0},
   {".ii", "@c++-cpp-output", 0, 0, 0},
   {"@c++-cpp-output",
-   "%{!M:%{!MM:%{!E:\
-    cc1plus -fpreprocessed %i %(cc1_options) %2\
-    %{!fsyntax-only:%(invoke_as)}}}}", 0, 0, 0},
+      "%{!E:%{!M:%{!MM:"
+      "   cc1plus -fpreprocessed %i %(cc1_options) %2"
+      "   %{!fsyntax-only:%(invoke_as)}}}}", 0, 0, 0},

gcc/cp/module.c

@@ -2827,6 +2827,9 @@ bool module_state_hash::equal (const value_type existing,
 /* Mapper name.  */
 static const char *module_mapper_name;
 
+/* Legacy header mode.  */
+static const char *module_header_name;
+
 /* BMI repository path and workspace.  */
 static char *bmi_repo;
 static size_t bmi_repo_length;
@@ -10736,8 +10739,28 @@ atom_module_preamble (location_t loc, line_maps *lmaps)
 void
 init_module_processing ()
 {
-  if (pch_file)
-    error ("modules and PCH are incompatible");
+  gcc_assert (pch_file);
+
+  if (module_header_name && !module_header_name[0])
+    {
+      /* Set the module header name from the main_input_filename.  */
+      const char *main = main_input_filename;
+      size_t len = strlen (main);
+      for (; len >= 2; len--)
+	if (IS_DIR_SEPARATOR (main[len-1]))
+	  {
+	    /* Is this '//' or '/./'?  */
+	    size_t peek = len - 2;
+	    if (peek && main[peek] == '.')
+	      peek--;
+	    if (IS_DIR_SEPARATOR (main[peek]))
+	      break;
+	  }
+      if (len < 2)
+	len = 0;
+      module_header_name = main + len;
+      else
+    }
 
   module_state::init ();
 }
@@ -10844,7 +10867,9 @@ maybe_repeat_preamble (location_t loc, int count ATTRIBUTE_UNUSED, cpp_reader *)
 }
 
 /* If CODE is a module option, handle it & return true.  Otherwise
-   return false.  */
+   return false.  For unknown reasons I cannot get the option
+   generation machinery to set fmodule-mapper pr -fmodule-header to
+   make a string type option variable.  */
 
 bool
 handle_module_option (unsigned code, const char *str, int num)
@@ -10861,6 +10886,15 @@ handle_module_option (unsigned code, const char *str, int num)
       flag_module_preamble = num;
       return true;
 
+    case OPT_fmodule_header:
+      str="";
+      /* FALLTHROUGH.  */
+    case OPT_fmodule_header_:
+      module_header_name = str;
+      /* Force atom.  */
+      flag_modules = -1;
+      return true;
+
     default:
       return false;
     }

gcc/doc/invoke.texi

@@ -488,7 +488,7 @@ Objective-C and Objective-C++ Dialects}.
 -dD  -dI  -dM  -dN  -dU @gol
 -fdebug-cpp  -fdirectives-only  -fdollars-in-identifiers  @gol
 -fexec-charset=@var{charset}  -fextended-identifiers  @gol
--finput-charset=@var{charset} -fmodule-prefix @gol
+-finput-charset=@var{charset} -fmodule-preamble @gol
 -fmacro-prefix-map=@var{old}=@var{new}  @gol
 -fno-canonical-system-headers @gol -fpch-deps  -fpch-preprocess  @gol
 -fpreprocessed -ftabstop=@var{width}  -ftrack-macro-expansion  @gol
@@ -29471,7 +29471,7 @@ Usually importing a module will load minimal information, defering the
 bulk of the loading to the point at which name-lookup inspects a
 particular namespace-scope name.
 
-The @option{-fmodule-prefix} option may be added when preprocessing with
+The @option{-fmodule-preamble} option may be added when preprocessing with
 @option{-E}.  This causes preprocessing to terminate once the Atom
 preamble is processed.  Build systems may need to determine the set of
 imports a compilation needed, and this allows that without the expense