[ELF2] Implement -T/--script

[davide]

Summary

This one tests more carefully SEARCH_DIR() as an added bonus.

[ruiu]

LGTM

[ruiu]

Actually there's one thing.

ELF/Options.td

109

def alias_script_T : Separate<["-"], "T">, Alias<script>;

ELF/Driver.cpp

if (Arg->getValue() == StringRef("now"))
       Config->ZNow = true;
 
   for (auto *Arg : Args) {
     switch (Arg->getOption().getID()) {
     case OPT_l:
       addFile(searchLibrary(Arg->getValue()));
       break;
     case OPT_INPUT:
+    case OPT_script:
       addFile(Arg->getValue());
       break;
     case OPT_Bstatic:
       Config->Static = true;
       break;
     case OPT_Bdynamic:
       Config->Static = false;
       break;

ELF/Options.td

def no_undefined : Flag<["--"], "no-undefined">,
   HelpText<"Report unresolved symbols even if the linker is creating a shared library">;
 
 def o : Separate<["-"], "o">, MetaVarName<"<path>">,
   HelpText<"Path to file to write output">;
 
 def rpath : Separate<["-"], "rpath">,
   HelpText<"Add a DT_RUNPATH to the output">;
 
+def script : Separate<["--"], "script">, HelpText<"Read linker script">;
+
 def shared : Flag<["-"], "shared">,
   HelpText<"Build a shared object">;
 
 def soname : Joined<["-"], "soname=">,
   HelpText<"Set DT_SONAME">;
 
 def sysroot : Joined<["--"], "sysroot=">,
   HelpText<"Set the system root">;

 def alias_entry_e : Separate<["-"], "e">, Alias<entry>;
 def alias_fini_fini : Joined<["-"], "fini=">, Alias<fini>;
 def alias_init_init : Joined<["-"], "init=">, Alias<init>;
 def alias_l__library : Joined<["--"], "library=">, Alias<l>;
 def alias_o_output : Joined<["--"], "output=">, Alias<o>;
 def alias_rpath_rpath : Joined<["-"], "rpath=">, Alias<rpath>;
 def alias_soname_h : Separate<["-"], "h">, Alias<soname>;
 def alias_soname_soname : Separate<["-"], "soname">, Alias<soname>;
+def alias_T : Separate<["-"], "T">, Alias<script>;
 def alias_undefined_u : Separate<["-"], "u">, Alias<undefined>;
 
 // Options listed below are silently ignored now.
 def O3 : Flag<["-"], "O3">;
 def as_needed : Flag<["--"], "as-needed">;
 def build_id : Flag<["--"], "build-id">;
 def eh_frame_hdr : Flag<["--"], "eh-frame-hdr">;
 def end_group : Flag<["--"], "end-group">;
 def gc_sections : Flag<["--"], "gc-sections">;
 def hash_style : Joined<["--"], "hash-style=">;
 def no_add_needed : Flag<["--"], "no-add-needed">;
 def no_as_needed : Flag<["--"], "no-as-needed">;
 def no_fatal_warnings : Flag<["--"], "no-fatal-warnings">;
 def start_group : Flag<["--"], "start-group">;
 def strip_all : Flag<["--"], "strip-all">;
 def version_script : Separate<["--"], "version-script">;

test/elf2/linkerscript2.s

+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-freebsd %s -o %t
+# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-freebsd \
+# RUN:   %p/Inputs/libsearch-dyn.s -o %tdyn.o
+# RUN: ld.lld2 -shared %tdyn.o -o %T/libls.so
+# RUN: echo "SEARCH_DIR(" %T ")" > %t.script
+# RUN: ld.lld2 -o %t2 --script %t.script -lls %t
+
+.globl _start,_bar
+_start: