head r329003: explain long options may use one or two dashes
head r338251: document -z ifunc-noplt option
head r338682: document -z interpose option

--- tools/lld/docs/ld.lld.1
+++ tools/lld/docs/ld.lld.1
@@ -3,7 +3,7 @@
 .\"
 .\" This man page documents only lld's ELF linking support, obtained originally
 .\" from FreeBSD.
-.Dd July 30, 2018
+.Dd September 14, 2018
 .Dt LD.LLD 1
 .Os
 .Sh NAME
@@ -25,6 +25,17 @@ is a drop-in replacement for the GNU BFD and gold link
 It accepts most of the same command line arguments and linker scripts
 as GNU linkers.
 .Pp
+Many options have both a single-letter and long form.
+When using the long form options other than those beginning with the
+letter
+.Cm o
+may be specified using either one or two dashes preceding the option name.
+Long options beginning with
+.Cm o
+require two dashes to avoid confusion with the
+.Fl o Ar path
+option.
+.Pp
 These options are available:
 .Bl -tag -width indent
 .It Fl -allow-multiple-definition
@@ -440,10 +451,23 @@ Make the main stack executable.
 Stack permissions are recorded in the
 .Dv PT_GNU_STACK
 segment.
+.It Cm ifunc-noplt
+Do not emit PLT entries for GNU ifuncs.
+Instead, preserve relocations for ifunc call sites so that they may
+be applied by a run-time loader.
+Note that this feature requires special loader support and will
+generally result in application crashes when used outside of freestanding
+environments.
 .It Cm initfirst
 Sets the
 .Dv DF_1_INITFIRST
 flag to indicate the module should be initialized first.
+.It Cm interpose
+Set the
+.Dv DF_1_INTERPOSE
+flag to indicate that the object is an interposer.
+Runtime linkers perform symbol resolution by first searching the application,
+followed by interposers, and then any other dependencies.
 .It Cm muldefs
 Do not error if a symbol is defined multiple times.
 The first definition will be used.