Handle multiple "--version-script" options.

[ikudrin]

Summary

Both ld.bfd and ld.gold can handle them.

In our case, several version script files are used to separate general and per-project settings.

[ruiu]

LGTM

ELF/Driver.cpp

for (auto *Arg : Args.filtered(OPT_dynamic_list))
       if (Optional<MemoryBufferRef> Buffer = readFile(Arg->getValue()))
         readDynamicList(*Buffer);
 
     for (auto *Arg : Args.filtered(OPT_export_dynamic_symbol))
       Config->DynamicList.push_back(
           {Arg->getValue(), /*IsExternCpp*/ false, /*HasWildcard*/ false});
   }
 
-  if (auto *Arg = Args.getLastArg(OPT_version_script))
+  for (auto *Arg : Args.filtered(OPT_version_script))
     if (Optional<MemoryBufferRef> Buffer = readFile(Arg->getValue()))
       readVersionScript(*Buffer);
 }
 
 // Some Config members do not directly correspond to any particular
 // command line options, but computed based on other Config values.
 // This function initialize such members. See Config.h for the details
 // of these values.

test/ELF/version-script.s

 # RUN: ld.lld --version-script %t6.script -shared %t.o %t2.so -o %t6.so 2>&1 | \
 # RUN:   FileCheck -check-prefix=WARN2 %s
 # WARN2: duplicate symbol 'foo1' in version script
 
 # RUN: echo "{ foo1; foo2; };" > %t.list
 # RUN: ld.lld --version-script %t.script --dynamic-list %t.list %t.o %t2.so -o %t2
 # RUN: llvm-readobj %t2 > /dev/null
 
+## Check that we can handle multiple "--version-script" options.
+# RUN: echo "VERSION_1.0 { global : foo1; local : *; };" > %t7a.script
+# RUN: echo "VERSION_2.0 { global: foo3; local: *; };" > %t7b.script
+# RUN: ld.lld --version-script %t7a.script --version-script %t7b.script -shared %t.o %t2.so -o %t7.so
+# RUN: llvm-readobj -dyn-symbols %t7.so | FileCheck --check-prefix=VERDSO %s
+
 # DSO:      DynamicSymbols [
 # DSO-NEXT:   Symbol {
 # DSO-NEXT:     Name: @
 # DSO-NEXT:     Value: 0x0
 # DSO-NEXT:     Size: 0
 # DSO-NEXT:     Binding: Local (0x0)
 # DSO-NEXT:     Type: None (0x0)
 # DSO-NEXT:     Other: 0