[ELF] Mention contents of reproduce archive and add help description.

Building on D60557 mention the name of the linker generated contents of
the reproduce archive, response.txt and version.txt.

Also write a shorter description in the ld.lld --help that is closer to
the documentation.

Differential Revision: https://reviews.llvm.org/D66641

llvm-svn: 369762

lld/ELF/Options.td

@@ -306,7 +306,7 @@ def push_state: F<"push-state">,
 def print_map: F<"print-map">,
   HelpText<"Print a link map to the standard output">;
 
-defm reproduce: Eq<"reproduce", "Dump linker invocation and input files for debugging">;
+defm reproduce: Eq<"reproduce", "Write a tar file containing input files and command line options to reproduce link">;
 
 defm rpath: Eq<"rpath", "Add a DT_RUNPATH to the output">;
 

lld/docs/ld.lld.1

@@ -408,9 +408,12 @@ Undo the effect of
 .It Fl -relocatable , Fl r
 Create relocatable object file.
 .It Fl -reproduce Ns = Ns Ar path
-Write a tar file containing all input files and a text file describing the link invocation to
+Write a tar file to
 .Ar path,
-so that you can easily re-run the linker with the same options and input files.
+containing all the input files needed to reproduce the link, a text file called
+response.txt containing the command line options and a text file called
+version.txt containing the output of ld.lld --version. The archive when
+unpacked can be used to re-run the linker with the same options and input files.
 .It Fl -retain-symbols-file Ns = Ns Ar file
 Retain only the symbols listed in the file.
 .It Fl -rpath Ns = Ns Ar value , Fl R Ar value