Index: ELF/Symbols.h
===================================================================
--- ELF/Symbols.h
+++ ELF/Symbols.h
@@ -302,6 +302,9 @@
 // Some linker-generated symbols need to be created as
 // DefinedRegular symbols.
 struct ElfSym {
+  // The content for __bss_start symbol.
+  static DefinedRegular *BssStart;
+
   // The content for _etext and etext symbols.
   static DefinedRegular *Etext;
   static DefinedRegular *Etext2;
Index: ELF/Symbols.cpp
===================================================================
--- ELF/Symbols.cpp
+++ ELF/Symbols.cpp
@@ -28,6 +28,7 @@
 using namespace lld;
 using namespace lld::elf;
 
+DefinedRegular *ElfSym::BssStart;
 DefinedRegular *ElfSym::Etext;
 DefinedRegular *ElfSym::Etext2;
 DefinedRegular *ElfSym::Edata;
Index: ELF/Writer.cpp
===================================================================
--- ELF/Writer.cpp
+++ ELF/Writer.cpp
@@ -846,6 +846,10 @@
   // __ehdr_start is the location of ELF file headers.
   addOptionalRegular<ELFT>("__ehdr_start", Out::ElfHeader, 0, STV_HIDDEN);
 
+  // __bss_start is the location of .bss.* sections.
+  ElfSym::BssStart =
+      addOptionalRegular<ELFT>("__bss_start", Out::ElfHeader, 0, STV_DEFAULT);
+
   auto Define = [](StringRef S, DefinedRegular *&Sym1, DefinedRegular *&Sym2) {
     Sym1 = addOptionalRegular<ELFT>(S, Out::ElfHeader, 0, STV_DEFAULT);
     assert(S.startswith("_"));
@@ -1675,6 +1679,9 @@
   if (LastRW)
     Set(ElfSym::Edata, ElfSym::Edata2, LastRW->First, LastRW->p_filesz);
 
+  if (OutputSection *Bss = findSection(".bss"))
+    Set(ElfSym::BssStart, nullptr, Bss, 0);
+
   // Setup MIPS _gp_disp/__gnu_local_gp symbols which should
   // be equal to the _gp symbol's value.
   if (Config->EMachine == EM_MIPS) {
Index: test/ELF/Inputs/bss-start.s
===================================================================
--- test/ELF/Inputs/bss-start.s
+++ test/ELF/Inputs/bss-start.s
@@ -0,0 +1,13 @@
+.rodata
+.globl a
+.size a, 4
+.type a, @object
+a:
+.word 1
+
+.section .data,"aw",%progbits
+.globl b
+.size b, 4
+.type b, @object
+b:
+.word 2
Index: test/ELF/bss-start.s
===================================================================
--- test/ELF/bss-start.s
+++ test/ELF/bss-start.s
@@ -0,0 +1,21 @@
+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t
+# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %p/Inputs/bss-start.s -o %t2.o
+# RUN: ld.lld -shared %t2.o -o %t.so
+# RUN: ld.lld %t %t.so -o %t2
+# RUN: llvm-objdump -t -section-headers %t2 | FileCheck %s
+
+# CHECK: Sections:
+# CHECK: Idx Name          Size      Address          Type
+# CHECK:   7 .bss.rel.ro   00000004 00000000002020b0 BSS
+# CHECK:   8 .bss          00000008 0000000000203000 BSS
+# CHECK: SYMBOL TABLE:
+# CHECK: 0000000000203000  .bss 00000000 __bss_start
+
+.global __bss_start
+.text
+_start:
+.comm sym1,4,4
+
+ movl $1, a
+ movl $1, b
Index: test/ELF/bss-start2.s
===================================================================
--- test/ELF/bss-start2.s
+++ test/ELF/bss-start2.s
@@ -0,0 +1,17 @@
+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t
+# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %p/Inputs/bss-start.s -o %t2.o
+# RUN: ld.lld -shared %t2.o -o %t.so
+# RUN: ld.lld %t %t.so -o %t2
+# RUN: llvm-objdump -t -section-headers %t2 | FileCheck %s
+
+# CHECK: Sections:
+# CHECK: Idx Name          Size      Address          Type
+# CHECK:   7 .bss          00000004 0000000000203000 BSS
+# CHECK: SYMBOL TABLE:
+# CHECK: 0000000000203000  .bss 00000000 __bss_start
+
+.global __bss_start
+.text
+_start:
+ movl $1, b
Index: test/ELF/bss-start3.s
===================================================================
--- test/ELF/bss-start3.s
+++ test/ELF/bss-start3.s
@@ -0,0 +1,16 @@
+
+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t
+# RUN: ld.lld %t -o %t2
+# RUN: llvm-objdump -t -section-headers %t2 | FileCheck %s
+
+# CHECK: Sections:
+# CHECK: Idx Name          Size      Address          Type
+# CHECK:   2 .bss          00000004 0000000000201000 BSS
+# CHECK: SYMBOL TABLE:
+# CHECK: 0000000000201000  .bss 00000000 __bss_start
+
+.global __bss_start
+.text
+_start:
+.comm sym1,4,4