[ELF2] Correctly set bits when -z now is specified

[davide]

Summary

The option now just sets NOW bit in DT_FLAGS_1 but some loaders (e.g. FreeBSD) seem to requier also BIND_NOW bit to be set in DT_FLAGS. This is, also, what ld.bfd and gold do.

[ruiu]

LGTM

lld/trunk/ELF/OutputSections.cpp

template <class ELFT> void DynamicSection<ELFT>::finalize() {
   if (Symbol *S = SymTab.getSymbols().lookup(Config->Init))
     InitSym = dyn_cast<ELFSymbolBody<ELFT>>(S->Body);
   if (Symbol *S = SymTab.getSymbols().lookup(Config->Fini))
     FiniSym = dyn_cast<ELFSymbolBody<ELFT>>(S->Body);
   if (InitSym)
     ++NumEntries; // DT_INIT
   if (FiniSym)
     ++NumEntries; // DT_FINI
-  if (Config->Bsymbolic)
+  if (Config->Bsymbolic || Config->ZNow)
     ++NumEntries; // DT_FLAGS
   if (Config->ZNodelete || Config->ZNow)
     ++NumEntries; // DT_FLAGS_1
   ++NumEntries; // DT_NULL
 
   Header.sh_size = NumEntries * Header.sh_entsize;
 }
 
template <class ELFT> void DynamicSection<ELFT>::writeTo(uint8_t *Buf) {
   if (InitSym)
     WritePtr(DT_INIT, getSymVA<ELFT>(*InitSym));
   if (FiniSym)
     WritePtr(DT_FINI, getSymVA<ELFT>(*FiniSym));
 
   uint32_t Flags = 0;
   if (Config->Bsymbolic)
     Flags |= DF_SYMBOLIC;
+  if (Config->ZNow)
+    Flags |= DF_BIND_NOW;
   if (Flags)
     WriteVal(DT_FLAGS, Flags);
   Flags = 0;
   if (Config->ZNodelete)
     Flags |= DF_1_NODELETE;
   if (Config->ZNow)
     Flags |= DF_1_NOW;
   if (Flags)

lld/trunk/test/elf2/dt_flags.s

 # REQUIRES: x86
 
 # RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t
 # RUN: ld.lld2 -shared %t -o %t.so
 # RUN: ld.lld2 -z now -z nodelete -Bsymbolic %t %t.so -o %t1
 # RUN: ld.lld2 %t %t.so -o %t2
 # RUN: llvm-readobj -dynamic-table %t1 | FileCheck -check-prefix=FLAGS %s
 # RUN: llvm-readobj -dynamic-table %t2 | FileCheck %s
 
 # FLAGS: DynamicSection [
-# FLAGS:   0x000000000000001E FLAGS SYMBOLIC
+# FLAGS:   0x000000000000001E FLAGS SYMBOLIC BIND_NOW
 # FLAGS:   0x000000006FFFFFFB FLAGS_1 NOW NODELETE
 # FLAGS: ]
 
 # CHECK: DynamicSection [
-# CHECK-NOT:   0x000000000000001E FLAGS SYMBOLIC
+# CHECK-NOT:   0x000000000000001E FLAGS SYMBOLIC BIND_NOW
 # CHECK-NOT:   0x000000006FFFFFFB FLAGS_1 NOW NODELETE
 # CHECK: ]
 
 .globl _start
 _start: