Index: ELF/Writer.cpp
===================================================================
--- ELF/Writer.cpp
+++ ELF/Writer.cpp
@@ -441,6 +441,10 @@
           DynType = Target->TlsGotRel;
         else if (Preemptible)
           DynType = Target->GotRel;
+        else if (Body.isUndefined())
+          // Weak undefined symbols evaluate to zero, so don't create
+          // relocations for them.
+          continue;
         else
           DynType = Target->RelativeRel;
         Out<ELFT>::RelaDyn->addReloc({DynType, Out<ELFT>::Got,
Index: test/ELF/pie-weak.s
===================================================================
--- /dev/null
+++ test/ELF/pie-weak.s
@@ -0,0 +1,12 @@
+# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t.o
+# RUN: ld.lld -pie %t.o -o %t
+# RUN: llvm-readobj -r %t | FileCheck %s
+
+# CHECK:      Relocations [
+# CHECK-NEXT: ]
+
+.weak foo
+
+.globl _start
+_start:
+mov foo@gotpcrel(%rip), %rax