[ELF2] Add support for -Bsymbolic.

llvm-svn: 250225

lld/ELF/Config.h

@@ -44,6 +44,7 @@ struct Configuration {
   std::vector<llvm::StringRef> SearchPaths;
   bool AllowMultipleDefinition;
   bool AsNeeded = false;
+  bool Bsymbolic;
   bool DiscardAll;
   bool DiscardLocals;
   bool DiscardNone;

lld/ELF/Driver.cpp

@@ -136,6 +136,7 @@ void LinkerDriver::createFiles(opt::InputArgList &Args) {
   }
 
   Config->AllowMultipleDefinition = Args.hasArg(OPT_allow_multiple_definition);
+  Config->Bsymbolic = Args.hasArg(OPT_Bsymbolic);
   Config->DiscardAll = Args.hasArg(OPT_discard_all);
   Config->DiscardLocals = Args.hasArg(OPT_discard_locals);
   Config->DiscardNone = Args.hasArg(OPT_discard_none);

lld/ELF/Options.td

@@ -1,5 +1,8 @@
 include "llvm/Option/OptParser.td"
 
+def Bsymbolic: Flag<["-"], "Bsymbolic">,
+  HelpText<"Bind defined symbols locally">;
+
 def Bdynamic: Flag<["-"], "Bdynamic">,
   HelpText<"Link against shared libraries">;
 

lld/ELF/OutputSections.cpp

@@ -293,8 +293,10 @@ template <class ELFT> void DynamicSection<ELFT>::finalize() {
     ++NumEntries; // DT_INIT
   if (FiniSym)
     ++NumEntries; // DT_FINI
-  if (Config->ZNow)
+  if (Config->ZNow || Config->Bsymbolic)
     ++NumEntries; // DT_FLAGS_1
+  if (Config->Bsymbolic)
+    ++NumEntries; // DT_SYMBOLIC
 
   ++NumEntries; // DT_NULL
 
@@ -366,8 +368,13 @@ template <class ELFT> void DynamicSection<ELFT>::writeTo(uint8_t *Buf) {
   if (FiniSym)
     WritePtr(DT_FINI, getSymVA<ELFT>(*FiniSym));
 
+  uint32_t Flags = 0;
+  if (Config->Bsymbolic)
+    Flags |= DF_SYMBOLIC;
   if (Config->ZNow)
-    WriteVal(DT_FLAGS_1, DF_1_NOW);
+    Flags |= DF_1_NOW;
+  if (Flags)
+    WriteVal(DT_FLAGS_1, Flags);
 
   WriteVal(DT_NULL, 0);
 }

lld/test/elf2/dt_flags.s

@@ -2,17 +2,17 @@
 
 # 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 %t %t.so -o %t1
+# RUN: ld.lld2 -z now -Bsymbolic %t %t.so -o %t1
 # RUN: ld.lld2 %t %t.so -o %t2
-# RUN: llvm-readobj -dynamic-table %t1 | FileCheck -check-prefix=NOW %s
+# RUN: llvm-readobj -dynamic-table %t1 | FileCheck -check-prefix=FLAGS %s
 # RUN: llvm-readobj -dynamic-table %t2 | FileCheck %s
 
-# NOW: DynamicSection [
-# NOW:   0x000000006FFFFFFB FLAGS_1 NOW
-# NOW: ]
+# FLAGS: DynamicSection [
+# FLAGS:   0x000000006FFFFFFB FLAGS_1 NOW GLOBAL
+# FLAGS: ]
 
 # CHECK: DynamicSection [
-# CHECK-NOT:   0x000000006FFFFFFB FLAGS_1 NOW
+# CHECK-NOT:   0x000000006FFFFFFB FLAGS_1 NOW GLOBAL
 # CHECK: ]
 
 .globl _start