Index: lld/ELF/Arch/AVR.cpp
===================================================================
--- lld/ELF/Arch/AVR.cpp
+++ lld/ELF/Arch/AVR.cpp
@@ -28,6 +28,7 @@
 #include "InputFiles.h"
 #include "Symbols.h"
 #include "Target.h"
+#include "Thunks.h"
 #include "lld/Common/ErrorHandler.h"
 #include "llvm/BinaryFormat/ELF.h"
 #include "llvm/Support/Endian.h"
@@ -42,9 +43,13 @@
 namespace {
 class AVR final : public TargetInfo {
 public:
+  AVR() { needsThunks = true; }
   uint32_t calcEFlags() const override;
   RelExpr getRelExpr(RelType type, const Symbol &s,
                      const uint8_t *loc) const override;
+  bool needsThunk(RelExpr expr, RelType type, const InputFile *file,
+                  uint64_t branchAddr, const Symbol &s,
+                  int64_t a) const override;
   void relocate(uint8_t *loc, const Relocation &rel,
                 uint64_t val) const override;
 };
@@ -98,6 +103,20 @@
   write16le(loc, (read16le(loc) & 0xf0f0) | (val & 0xf0) << 4 | (val & 0x0f));
 }
 
+bool AVR::needsThunk(RelExpr expr, RelType type, const InputFile *file,
+                     uint64_t branchAddr, const Symbol &s, int64_t a) const {
+  switch (type) { 
+  case R_AVR_LO8_LDI_GS:
+  case R_AVR_HI8_LDI_GS:
+    // A thunk is needed if the symbol's virtual address is out of range
+    // [0, 0x1fffe].
+    assert((s.getVA() & 1) == 0 && "function address must be aligned to 2.");
+    return s.getVA() >= 0x20000;
+  default:
+    return false;
+  }
+}
+
 void AVR::relocate(uint8_t *loc, const Relocation &rel, uint64_t val) const {
   switch (rel.type) {
   case R_AVR_8:
Index: lld/ELF/Thunks.cpp
===================================================================
--- lld/ELF/Thunks.cpp
+++ lld/ELF/Thunks.cpp
@@ -268,6 +268,15 @@
   void addSymbols(ThunkSection &isec) override;
 };
 
+// AVR thunk
+class AVRThunk : public Thunk {
+public:
+  AVRThunk(Symbol &dest, int64_t addend) : Thunk(dest, addend) {}
+  uint32_t size() override { return 4; }
+  void writeTo(uint8_t *buf) override;
+  void addSymbols(ThunkSection &isec) override;
+};
+
 // MIPS LA25 thunk
 class MipsThunk final : public Thunk {
 public:
@@ -847,6 +856,16 @@
   addSymbol("$d", STT_NOTYPE, 16, isec);
 }
 
+void AVRThunk::writeTo(uint8_t *buf) {
+  write32(buf, 0x940c); // Use the direct jump instruction.
+  target->relocateNoSym(buf, R_AVR_CALL, destination.getVA());
+}
+
+void AVRThunk::addSymbols(ThunkSection &isec) {
+  addSymbol(saver().save("__AVRThunk_" + destination.getName()), STT_FUNC, 0,
+            isec);
+}
+
 // Write MIPS LA25 thunk code to call PIC function from the non-PIC one.
 void MipsThunk::writeTo(uint8_t *buf) {
   uint64_t s = destination.getVA();
@@ -1267,6 +1286,16 @@
   fatal("unrecognized relocation type");
 }
 
+static Thunk *addThunkAVR(RelType type, Symbol &s, int64_t a) {
+  switch (type) {
+  case R_AVR_LO8_LDI_GS:
+  case R_AVR_HI8_LDI_GS:
+    return make<AVRThunk>(s, a);
+  default:
+    fatal("unrecognized relocation type " + toString(type));
+  }
+}
+
 static Thunk *addThunkMips(RelType type, Symbol &s) {
   if ((s.stOther & STO_MIPS_MICROMIPS) && isMipsR6())
     return make<MicroMipsR6Thunk>(s);
@@ -1318,6 +1347,8 @@
     return addThunkAArch64(rel.type, s, a);
   case EM_ARM:
     return addThunkArm(rel.type, s, a);
+  case EM_AVR:
+    return addThunkAVR(rel.type, s, a);
   case EM_MIPS:
     return addThunkMips(rel.type, s);
   case EM_PPC:
Index: lld/test/ELF/avr-thunk.s
===================================================================
--- /dev/null
+++ lld/test/ELF/avr-thunk.s
@@ -0,0 +1,27 @@
+; REQUIRES: avr
+; RUN: llvm-mc -filetype=obj -triple=avr -mcpu=atmega2560 %s -o %t.o
+; RUN: ld.lld %t.o --defsym=a=0x1fffe --defsym=b=0x20000 -o %t
+; RUN: llvm-objdump -d --print-imm-hex --mcpu=atmega2560 %t | FileCheck %s
+
+.section .LDI,"ax",@progbits
+
+; CHECK:       000110b4 <__AVRThunk_b>:
+; CHECK-NEXT:    jmp   0x20000
+; CHECK:       000110b8 <__init>:
+; CHECK-NEXT:    ldi     r30, 0xff
+; CHECK-NEXT:    ldi     r31, 0xff
+; CHECK-NEXT:    eicall
+; CHECK-NEXT:    ldi     r30, 0x5a
+; CHECK-NEXT:    ldi     r31, 0x88
+; CHECK-NEXT:    eicall
+; CHECK-NOT:   __AVRThunk_a
+
+__init:
+;; No thunk is needed, since the destination is in range [0, 0x1fffe].
+ldi r30, lo8_gs(a)  ; R_AVR_LO8_LDI_GS
+ldi r31, hi8_gs(a)  ; R_AVR_HI8_LDI_GS
+eicall
+;; A thunk is needed, since the destination is out of range.
+ldi r30, lo8_gs(b)  ; R_AVR_LO8_LDI_GS
+ldi r31, hi8_gs(b)  ; R_AVR_HI8_LDI_GS
+eicall