compiler: Add -fgo-pkgpath option.

	* lang.opt: Add -fgo-pkgpath.
	* go-lang.c (go_pkgpath): New static variable.
	(go_prefix): New static variable.
	(go_langhook_init): Pass go_pkgpath and go_prefix to
	go_create_gogo.
	(go_langhook_handle_option): Handle -fgo-pkgpath.  Change
	-fgo-prefix handling to just set go_prefix.
	* go-c.h (go_set_prefix): Don't declare.
	(go_create_gogo): Add pkgpath and prefix to declaration.
	* go-gcc.cc (Gcc_backend::global_variable): Change unique_prefix
	to pkgpath.  Don't include the package name in the asm name.
	* gccgo.texi (Invoking gccgo): Document -fgo-pkgpath.  Update the
	docs for -fgo-prefix.

From-SVN: r187356

1 files changed, 23 insertions, 5 deletions

diff --git a/gcc/go/gccgo.texi b/gcc/go/gccgo.texi
index 5d0efb4..a5e37e7 100644
--- a/gcc/go/gccgo.texi
+++ b/gcc/go/gccgo.texi
@@ -157,14 +157,32 @@ compile time.
 When linking, specify a library search directory, as with
 @command{gcc}.
 
+@item -fgo-pkgpath=@var{string}
+@cindex @option{-fgo-pkgpath}
+Set the package path to use.  This sets the value returned by the
+PkgPath method of reflect.Type objects.  It is also used for the names
+of globally visible symbols.  The argument to this option should
+normally be the string that will be used to import this package after
+it has been installed; in other words, a pathname within the
+directories specified by the @option{-I} option.
+
 @item -fgo-prefix=@var{string}
 @cindex @option{-fgo-prefix}
+An alternative to @option{-fgo-pkgpath}.  The argument will be
+combined with the package name from the source file to produce the
+package path.  If @option{-fgo-pkgpath} is used, @option{-fgo-prefix}
+will be ignored.
+
 Go permits a single program to include more than one package with the
-same name.  This option is required to make this work with
-@command{gccgo}.  The argument to this option may be any string.  Each
-package with the same name must use a distinct @option{-fgo-prefix}
-option.  The argument is typically the full path under which the
-package will be installed, as that must obviously be unique.
+same name in the @code{package} clause in the source file, though
+obviously the two packages must be imported using different pathnames.
+In order for this to work with @command{gccgo}, either
+@option{-fgo-pkgpath} or @option{-fgo-prefix} must be specified when
+compiling a package.
+
+Using either @option{-fgo-pkgpath} or @option{-fgo-prefix} disables
+the special treatment of the @code{main} package and permits that
+package to be imported like any other.
 
 @item -frequire-return-statement
 @itemx -fno-require-return-statement