--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lld/test/ELF/weak-undef-shared.s	Thu Feb 13 15:10:13 2020 +0900
@@ -0,0 +1,40 @@
+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64 %s -o %t.o
+# RUN: ld.lld -shared %t.o -o %t.so
+
+# RUN: echo '.data; .weak foo; .quad foo' | llvm-mc -filetype=obj -triple=x86_64 - -o %t1.o
+# RUN: echo '.data; .quad foo' | llvm-mc -filetype=obj -triple=x86_64 - -o %t2.o
+# RUN: ld.lld -shared %t2.o -o %t2.so
+
+## If the first undefined reference is weak, the binding changes to
+## STB_WEAK.
+# RUN: ld.lld %t1.o %t.so -o %t
+# RUN: llvm-readelf --dyn-syms %t | FileCheck --check-prefix=WEAK %s
+# RUN: ld.lld %t.so %t1.o -o %t
+# RUN: llvm-readelf --dyn-syms %t | FileCheck --check-prefix=WEAK %s
+
+## The binding remains STB_WEAK if there is no STB_GLOBAL undefined reference.
+# RUN: ld.lld %t1.o %t.so %t1.o -o %t
+# RUN: llvm-readelf --dyn-syms %t | FileCheck --check-prefix=WEAK %s
+# RUN: ld.lld %t.so %t1.o %t1.o -o %t
+# RUN: llvm-readelf --dyn-syms %t | FileCheck --check-prefix=WEAK %s
+
+## The binding changes back to STB_GLOBAL if there is a STB_GLOBAL undefined reference.
+# RUN: ld.lld %t1.o %t.so %t2.o -o %t
+# RUN: llvm-readelf --dyn-syms %t | FileCheck --check-prefix=GLOBAL %s
+# RUN: ld.lld %t2.o %t.so %t1.o -o %t
+# RUN: llvm-readelf --dyn-syms %t | FileCheck --check-prefix=GLOBAL %s
+
+## Check the binding (weak) is not affected by the STB_GLOBAL undefined
+## reference in %t2.so
+# RUN: ld.lld %t1.o %t2.so -o %t
+# RUN: llvm-readelf --dyn-syms %t | FileCheck --check-prefix=WEAK %s
+
+# RUN: ld.lld %t2.so %t1.o -o %t
+# RUN: llvm-readelf --dyn-syms %t | FileCheck --check-prefix=WEAK %s
+
+# WEAK:   NOTYPE WEAK   DEFAULT UND foo
+# GLOBAL: NOTYPE GLOBAL DEFAULT UND foo
+
+.globl foo
+foo: