Handle empty dynamic lists.

llvm-svn: 312820

lld/ELF/Config.h

@@ -126,6 +126,7 @@ struct Configuration {
   bool GcSections;
   bool GdbIndex;
   bool GnuHash;
+  bool HasDynamicList = false;
   bool ICF;
   bool MipsN32Abi = false;
   bool NoGnuUnique;

lld/ELF/ScriptParser.cpp

@@ -180,6 +180,7 @@ static ExprValue bitOr(ExprValue A, ExprValue B) {
 }
 
 void ScriptParser::readDynamicList() {
+  Config->HasDynamicList = true;
   expect("{");
   std::vector<SymbolVersion> Locals;
   std::vector<SymbolVersion> Globals;

lld/ELF/Writer.cpp

@@ -1244,7 +1244,7 @@ static bool computeIsPreemptible(const SymbolBody &B) {
     return true;
 
   // If we have a dynamic list it specifies which local symbols are preemptible.
-  if (!Config->DynamicList.empty())
+  if (Config->HasDynamicList)
     return false;
 
   if (!Config->Shared)

lld/test/ELF/dynamic-list-empty.s

@@ -0,0 +1,18 @@
+# REQUIRES: x86
+
+# BFD reports a parse error on empty lists, but it is clear how to
+# handle it.
+
+# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t.o
+# RUN: echo "{ };" > %t.list
+# RUN: ld.lld -dynamic-list %t.list -shared %t.o -o %t.so
+# RUN: llvm-readobj -r %t.so | FileCheck  %s
+
+# CHECK:      Relocations [
+# CHECK-NEXT: ]
+
+        .globl foo
+foo:
+        ret
+
+        call foo@PLT