diff --git a/clang/include/clang/Basic/Attr.td b/clang/include/clang/Basic/Attr.td
--- a/clang/include/clang/Basic/Attr.td
+++ b/clang/include/clang/Basic/Attr.td
@@ -1345,6 +1345,13 @@
   let SimpleHandler = 1;
 }
 
+def Addrsig : InheritableAttr {
+  let Spellings = [Clang<"addrsig">];
+  let Documentation = [AddrsigDocs];
+  let Subjects = SubjectList<[Function, Var]>;
+  let SimpleHandler = 1;
+}
+
 def FastCall : DeclOrTypeAttr {
   let Spellings = [GCC<"fastcall">, Keyword<"__fastcall">,
                    Keyword<"_fastcall">];
diff --git a/clang/include/clang/Basic/AttrDocs.td b/clang/include/clang/Basic/AttrDocs.td
--- a/clang/include/clang/Basic/AttrDocs.td
+++ b/clang/include/clang/Basic/AttrDocs.td
@@ -443,6 +443,18 @@
   }];
 }
 
+def AddrsigDocs : Documentation {
+  let Category = DocCatFunction;
+  let Content = [{
+Functions or variables attached with ``addrsig`` will be put into the
+address-significant table, which disables identical code folding (ICF) on 
+setions in it (only useful when linking with lld). For the COFF port of lld, the
+default icf (``/OPT:safeicf``) will fold code sections regardless the existance 
+of address-significant table. So, ``/OPT:safeicf`` is needed if you don't want 
+code sections folding when they are in the table.
+  }];
+}
+
 def AssertCapabilityDocs : Documentation {
   let Category = DocCatFunction;
   let Heading = "assert_capability, assert_shared_capability";
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -2054,6 +2054,9 @@
     if (MD->isVirtual())
       F->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
 
+  if (FD->hasAttr<AddrsigAttr>())
+    F->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Significant);
+
   // Don't emit entries for function declarations in the cross-DSO mode. This
   // is handled with better precision by the receiving DSO. But if jump tables
   // are non-canonical then we need type metadata in order to produce the local
@@ -4294,6 +4297,9 @@
   if (D->hasAttr<AnnotateAttr>())
     AddGlobalAnnotations(D, GV);
 
+  if (D->hasAttr<AddrsigAttr>())
+    GV->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Significant);
+
   // Set the llvm linkage type as appropriate.
   llvm::GlobalValue::LinkageTypes Linkage =
       getLLVMLinkageVarDefinition(D, GV->isConstant());
diff --git a/clang/test/CodeGenCXX/attr-addrsig.cpp b/clang/test/CodeGenCXX/attr-addrsig.cpp
new file mode 100644
--- /dev/null
+++ b/clang/test/CodeGenCXX/attr-addrsig.cpp
@@ -0,0 +1,61 @@
+// RUN: %clang_cc1 -S -emit-llvm %s -triple x86_64-unknown-linux-gnu -O2 -o - | FileCheck %s
+
+// CHECK: @i1 = {{.*}}unnamed_addr
+// CHECK-NEXT: @i2 = {{.*}}unnamed_addr
+int i1;
+int i2 = 0;
+
+// CHECK: @i3 = {{.*}}significant_addr
+// CHECK-NEXT: @i4 = {{.*}}significant_addr
+[[clang::addrsig]] int i3;
+[[clang::addrsig]] int i4 = 0;
+
+// CHECK-DAG: declare void @_Z2f1i{{.*}}unnamed_addr
+void f1(int i);
+// CHECK-DAG: define dso_local i32 @_Z2f2i{{.*}}unnamed_addr
+int f2(int i) {
+    f1(i);
+    return i * 2;
+}
+
+// CHECK-DAG: declare void @_Z2f3i{{.*}}significant_addr
+[[clang::addrsig]] void f3(int i);
+void f3(int i);
+// CHECK-DAG: define dso_local i32 @_Z2f4i{{.*}}significant_addr
+[[clang::addrsig]] int f4(int i) {
+    f3(i);
+    return i * 2;
+}
+
+
+// CHECK-DAG: declare void @_ZN1AC1Ev{{.*}}unnamed_addr
+// CHECK-DAG: declare void @_ZN1AD1Ev{{.*}}unnamed_addr
+// CHECK-DAG: declare void @_ZN1A2f1Ev{{.*}}unnamed_addr
+// CHECK-DAG: declare void @_ZN1A2f2Ev{{.*}}unnamed_addr
+
+// CHECK-DAG: declare void @_ZN1BC1Ev{{.*}}significant_addr
+// CHECK-DAG: declare void @_ZN1BD1Ev{{.*}}significant_addr
+// CHECK-DAG: declare void @_ZN1B2f1Ev{{.*}}significant_addr
+// CHECK-DAG: declare void @_ZN1B2f2Ev{{.*}}significant_addr
+struct A {
+    A();
+    ~A();
+    void f1();
+    virtual void f2();
+};
+
+struct B {
+    [[clang::addrsig]] B();
+    [[clang::addrsig]] ~B();
+    [[clang::addrsig]] void f1();
+    [[clang::addrsig]] virtual void f2();
+};
+
+void test() {
+    A a;
+    B b;
+    a.f1();
+    a.f2();
+    b.f1();
+    b.f2();
+}
diff --git a/clang/test/Misc/pragma-attribute-supported-attributes-list.test b/clang/test/Misc/pragma-attribute-supported-attributes-list.test
--- a/clang/test/Misc/pragma-attribute-supported-attributes-list.test
+++ b/clang/test/Misc/pragma-attribute-supported-attributes-list.test
@@ -10,6 +10,7 @@
 // CHECK-NEXT: AVRSignal (SubjectMatchRule_function)
 // CHECK-NEXT: AbiTag (SubjectMatchRule_record_not_is_union, SubjectMatchRule_variable, SubjectMatchRule_function, SubjectMatchRule_namespace)
 // CHECK-NEXT: AcquireHandle (SubjectMatchRule_function, SubjectMatchRule_type_alias, SubjectMatchRule_variable_is_parameter)
+// CHECK-NEXT: Addrsig (SubjectMatchRule_function, SubjectMatchRule_variable)
 // CHECK-NEXT: Alias (SubjectMatchRule_function, SubjectMatchRule_variable_is_global)
 // CHECK-NEXT: AlignValue (SubjectMatchRule_variable, SubjectMatchRule_type_alias)
 // CHECK-NEXT: AllocSize (SubjectMatchRule_function)
diff --git a/clang/test/Sema/attr-addrsig.c b/clang/test/Sema/attr-addrsig.c
new file mode 100644
--- /dev/null
+++ b/clang/test/Sema/attr-addrsig.c
@@ -0,0 +1,8 @@
+// RUN: %clang_cc1 -verify -fsyntax-only %s
+
+__attribute__((addrsig)) int i;
+
+__attribute__((addrsig)) void f();
+__attribute__((addrsig)) void g() {}
+
+struct __attribute__((addrsig)) A {}; // expected-warning {{'addrsig' attribute only applies to functions and variables}}