Handle _DYNAMIC correctly in the x86_64 backend.

llvm-svn: 190302

lld/lib/ReaderWriter/ELF/Atoms.h

@@ -891,6 +891,31 @@ public:
   virtual ArrayRef<uint8_t> rawContent() const { return ArrayRef<uint8_t>(); }
 };
 
+class DYNAMICAtom : public SimpleDefinedAtom {
+public:
+  DYNAMICAtom(const File &f) : SimpleDefinedAtom(f) {}
+
+  virtual StringRef name() const { return "_DYNAMIC"; }
+
+  virtual Scope scope() const { return scopeLinkageUnit; }
+
+  virtual Merge merge() const { return mergeNo; }
+
+  virtual SectionChoice sectionChoice() const { return sectionCustomRequired; }
+
+  virtual StringRef customSectionName() const { return ".dynamic"; }
+
+  virtual ContentType contentType() const { return typeData; }
+
+  virtual uint64_t size() const { return 0; }
+
+  virtual ContentPermissions permissions() const { return permRW_; }
+
+  virtual Alignment alignment() const { return Alignment(0); }
+
+  virtual ArrayRef<uint8_t> rawContent() const { return ArrayRef<uint8_t>(); }
+};
+
 class InitFiniAtom : public SimpleDefinedAtom {
   StringRef _section;
 

lld/lib/ReaderWriter/ELF/X86_64/X86_64TargetHandler.cpp

@@ -21,5 +21,7 @@ X86_64TargetHandler::X86_64TargetHandler(X86_64LinkingContext &context)
 void X86_64TargetHandler::addFiles(InputFiles &f) {
   _gotFile.addAtom(*new (_gotFile._alloc) GLOBAL_OFFSET_TABLEAtom(_gotFile));
   _gotFile.addAtom(*new (_gotFile._alloc) TLSGETADDRAtom(_gotFile));
+  if (_context.isDynamic())
+    _gotFile.addAtom(*new (_gotFile._alloc) DYNAMICAtom(_gotFile));
   f.appendFile(_gotFile);
 }

lld/test/elf/entry.objtxt

@@ -12,8 +12,9 @@
 # RUN: llvm-nm -n %t1 | FileCheck %s
 # 
 # CHECK:  004001b0 T main
-# CHECK:  00401000 A _end
-# CHECK:  00401000 A end
+# CHECK:  00401060 D _DYNAMIC
+# CHECK:  00401060 A _end
+# CHECK:  00401060 A end
 # CHECK:           U _entrypoint
 
 defined-atoms: