Index: ELF/Config.h
===================================================================
--- ELF/Config.h
+++ ELF/Config.h
@@ -15,6 +15,7 @@
 #include "llvm/ADT/StringSet.h"
 #include "llvm/Support/CodeGen.h"
 #include "llvm/Support/ELF.h"
+#include "llvm/Support/Endian.h"
 
 #include <vector>
 
@@ -206,6 +207,12 @@
   bool isMips64EL() const {
     return EMachine == llvm::ELF::EM_MIPS && EKind == ELF64LEKind;
   }
+
+  llvm::support::endianness getEndian() const {
+    return (EKind == ELF32LEKind || EKind == ELF64LEKind)
+               ? llvm::support::endianness::little
+               : llvm::support::endianness::big;
+  }
 };
 
 // The only instance of Configuration struct.
Index: ELF/SyntheticSections.h
===================================================================
--- ELF/SyntheticSections.h
+++ ELF/SyntheticSections.h
@@ -135,7 +135,7 @@
 };
 
 // .note.gnu.build-id section.
-template <class ELFT> class BuildIdSection : public SyntheticSection {
+class BuildIdSection : public SyntheticSection {
   // First 16 bytes are a header.
   static const unsigned HeaderSize = 16;
 
@@ -760,7 +760,7 @@
 // Linker generated sections which can be used as inputs.
 template <class ELFT> struct In {
   static InputSection *ARMAttributes;
-  static BuildIdSection<ELFT> *BuildId;
+  static BuildIdSection *BuildId;
   static BssSection *Bss;
   static BssSection *BssRelRo;
   static InputSection *Common;
@@ -794,7 +794,7 @@
 template <class ELFT> InputSection *In<ELFT>::ARMAttributes;
 template <class ELFT> BssSection *In<ELFT>::Bss;
 template <class ELFT> BssSection *In<ELFT>::BssRelRo;
-template <class ELFT> BuildIdSection<ELFT> *In<ELFT>::BuildId;
+template <class ELFT> BuildIdSection *In<ELFT>::BuildId;
 template <class ELFT> InputSection *In<ELFT>::Common;
 template <class ELFT> DynamicSection<ELFT> *In<ELFT>::Dynamic;
 template <class ELFT> StringTableSection *In<ELFT>::DynStrTab;
Index: ELF/SyntheticSections.cpp
===================================================================
--- ELF/SyntheticSections.cpp
+++ ELF/SyntheticSections.cpp
@@ -330,16 +330,15 @@
   }
 }
 
-template <class ELFT>
-BuildIdSection<ELFT>::BuildIdSection()
+BuildIdSection::BuildIdSection()
     : SyntheticSection(SHF_ALLOC, SHT_NOTE, 1, ".note.gnu.build-id"),
       HashSize(getHashSize()) {}
 
-template <class ELFT> void BuildIdSection<ELFT>::writeTo(uint8_t *Buf) {
-  const endianness E = ELFT::TargetEndianness;
-  write32<E>(Buf, 4);                   // Name size
-  write32<E>(Buf + 4, HashSize);        // Content size
-  write32<E>(Buf + 8, NT_GNU_BUILD_ID); // Type
+void BuildIdSection::writeTo(uint8_t *Buf) {
+  const endianness E = Config->getEndian();
+  write32(Buf, 4, E);                   // Name size
+  write32(Buf + 4, HashSize, E);        // Content size
+  write32(Buf + 8, NT_GNU_BUILD_ID, E); // Type
   memcpy(Buf + 12, "GNU", 4);           // Name string
   HashBuf = Buf + 16;
 }
@@ -361,8 +360,7 @@
 // In order to utilize multiple cores, we first split data into 1MB
 // chunks, compute a hash for each chunk, and then compute a hash value
 // of the hash values.
-template <class ELFT>
-void BuildIdSection<ELFT>::computeHash(
+void BuildIdSection::computeHash(
     llvm::ArrayRef<uint8_t> Data,
     std::function<void(uint8_t *Dest, ArrayRef<uint8_t> Arr)> HashFn) {
   std::vector<ArrayRef<uint8_t>> Chunks = split(Data, 1024 * 1024);
@@ -385,8 +383,7 @@
   return this->Size - Size;
 }
 
-template <class ELFT>
-void BuildIdSection<ELFT>::writeBuildId(ArrayRef<uint8_t> Buf) {
+void BuildIdSection::writeBuildId(ArrayRef<uint8_t> Buf) {
   switch (Config->BuildId) {
   case BuildIdKind::Fast:
     computeHash(Buf, [](uint8_t *Dest, ArrayRef<uint8_t> Arr) {
@@ -2302,11 +2299,6 @@
 template class elf::MipsReginfoSection<ELF64LE>;
 template class elf::MipsReginfoSection<ELF64BE>;
 
-template class elf::BuildIdSection<ELF32LE>;
-template class elf::BuildIdSection<ELF32BE>;
-template class elf::BuildIdSection<ELF64LE>;
-template class elf::BuildIdSection<ELF64BE>;
-
 template class elf::GotSection<ELF32LE>;
 template class elf::GotSection<ELF32BE>;
 template class elf::GotSection<ELF64LE>;
Index: ELF/Writer.cpp
===================================================================
--- ELF/Writer.cpp
+++ ELF/Writer.cpp
@@ -357,7 +357,7 @@
   }
 
   if (Config->BuildId != BuildIdKind::None) {
-    In<ELFT>::BuildId = make<BuildIdSection<ELFT>>();
+    In<ELFT>::BuildId = make<BuildIdSection>();
     Add(In<ELFT>::BuildId);
   }