* NEWS: mention support for forward exports in PE-COFF dll's.

	* ld.texinfo: Expand documentation of EXPORT statements in
	PE-COFF .def files.

1 files changed, 55 insertions, 4 deletions

diff --git a/ld/ld.texinfo b/ld/ld.texinfo
index 3c0a101..4f809f3 100644
--- a/ld/ld.texinfo
+++ b/ld/ld.texinfo
@@ -5581,17 +5581,68 @@ Using a DEF file turns off the normal auto-export behavior, unless the
 Here is an example of a DEF file for a shared library called @samp{xyz.dll}:
 
 @example
-LIBRARY "xyz.dll" BASE=0x10000000
+LIBRARY "xyz.dll" BASE=0x20000000
 
 EXPORTS
 foo
 bar
 _bar = bar
+another_foo = abc.dll.afoo
+var1 DATA
 @end example 
 
-This example defines a base address and three symbols.  The third
-symbol is an alias for the second.  For the complete format
-specification see ld/deffilep.y in the binutils sources.
+This example defines a DLL with a non-default base address and five
+symbols in the export table. The third exported symbol @code{_bar} is an
+alias for the second. The fourth symbol, @code{another_foo} is resolved
+by "forwarding" to another module and treating it as an alias for
+@code{afoo} exported from the DLL @samp{abc.dll}. The final symbol
+@code{var1} is declared to be a data object.
+
+The complete specification of an export symbol is:
+
+@example
+EXPORTS
+  ( (  ( <name1> [ = <name2> ] )
+     | ( <name1> = <module-name> . <external-name>))
+  [ @@ <integer> ] [NONAME] [DATA] [CONSTANT] [PRIVATE] ) *
+@end example 
+
+Declares @samp{<name1>} as an exported symbol from the DLL, or declares
+@samp{<name1>} as an exported alias for @samp{<name2>}; or declares
+@samp{<name1>} as a "forward" alias for the symbol
+@samp{<external-name>} in the DLL @samp{<module-name>}.
+Optionally, the symbol may be exported by the specified ordinal
+@samp{<integer>} alias.
+
+The optional keywords that follow the declaration indicate:
+
+@code{NONAME}: Do not put the symbol name in the DLL's export table.  It
+will still be exported by its ordinal alias (either the value specified
+by the .def specification or, otherwise, the value assigned by the
+linker). The symbol name, however, does remain visible in the import
+library (if any), unless @code{PRIVATE} is also specified.
+
+@code{DATA}: The symbol is a variable or object, rather than a function.
+The import lib will export only an indirect reference to @code{foo} as
+the symbol @code{_imp__foo} (ie, @code{foo} must be resolved as
+@code{*_imp__foo}).
+
+@code{CONSTANT}: Like @code{DATA}, but put the undecorated @code{foo} as
+well as @code{_imp__foo} into the import library. Both refer to the
+read-only import address table's pointer to the variable, not to the
+variable itself. This can be dangerous. If the user code fails to add
+the @code{dllimport} attribute and also fails to explicitly add the
+extra indirection that the use of the attribute enforces, the
+application will behave unexpectedly.
+
+@code{PRIVATE}: Put the symbol in the DLL's export table, but do not put
+it into the static import library used to resolve imports at link time. The
+symbol can still be imported using the @code{LoadLibrary/GetProcAddress}
+API at runtime or by by using the GNU ld extension of linking directly to
+the DLL without an import library.
+ 
+See ld/deffilep.y in the binutils sources for the full specification of
+other DEF file statements
 
 @cindex creating a DEF file
 While linking a shared dll, @command{ld} is able to create a DEF file