Index: clang/docs/UsersManual.rst
===================================================================
--- clang/docs/UsersManual.rst
+++ clang/docs/UsersManual.rst
@@ -1677,6 +1677,27 @@
    on ELF targets when using the integrated assembler. This flag currently
    only has an effect on ELF targets.
 
+**-f[no]-unique-internal-linkage-names**
+
+   Controls whether Clang emits a unique (best-effort) symbol name for internal
+   linkage symbols.  When this option is set, compiler hashes the main source
+   file path from the command line and appends it to all internal symbols. If a
+   program contains multiple objects compiled with the same command-line source
+   file path, the symbols are not guaranteed to be unique.  This option is
+   particularly useful in attributing profile information to the correct
+   function when multiple functions with the same private linkage name exist
+   in the binary.
+
+   It should be noted that this option cannot guarantee uniqueness and the
+   following is an example where it is not unique when two modules contain
+   symbols with the same private linkage name:
+
+   .. code-block:: console
+
+     $ cd $P/foo && clang -c -funique-internal-linkage-names name_conflict.c
+     $ cd $P/bar && clang -c -funique-internal-linkage-names name_conflict.c
+     $ cd $P && clang foo/name_conflict.o && bar/name_conflict.o
+
 Profile Guided Optimization
 ---------------------------
 
Index: clang/include/clang/Basic/CodeGenOptions.def
===================================================================
--- clang/include/clang/Basic/CodeGenOptions.def
+++ clang/include/clang/Basic/CodeGenOptions.def
@@ -161,6 +161,7 @@
 CODEGENOPT(NoTrappingMath    , 1, 0) ///< Set when -fno-trapping-math is enabled.
 CODEGENOPT(NoNaNsFPMath      , 1, 0) ///< Assume FP arguments, results not NaN.
 CODEGENOPT(CorrectlyRoundedDivSqrt, 1, 0) ///< -cl-fp32-correctly-rounded-divide-sqrt
+CODEGENOPT(UniqueInternalLinkageNames, 1, 0) ///< Internal Linkage symbols get unique names.
 
 /// When false, this attempts to generate code as if the result of an
 /// overflowing conversion matches the overflowing behavior of a target's native
Index: clang/include/clang/Driver/Options.td
===================================================================
--- clang/include/clang/Driver/Options.td
+++ clang/include/clang/Driver/Options.td
@@ -2001,6 +2001,12 @@
 def fno_unique_section_names : Flag <["-"], "fno-unique-section-names">,
   Group<f_Group>, Flags<[CC1Option]>;
 
+def funique_internal_linkage_names : Flag <["-"], "funique-internal-linkage-names">,
+  Group<f_Group>, Flags<[CC1Option]>,
+  HelpText<"Uniqueify Internal Linkage Symbol Names by appending the MD5 hash of the module path">;
+def fno_unique_internal_linkage_names : Flag <["-"], "fno-unique-internal-linkage-names">,
+  Group<f_Group>;
+
 def fstrict_return : Flag<["-"], "fstrict-return">, Group<f_Group>,
   HelpText<"Always treat control flow paths that fall off the end of a "
            "non-void function as unreachable">;
Index: clang/lib/Driver/ToolChains/Clang.cpp
===================================================================
--- clang/lib/Driver/ToolChains/Clang.cpp
+++ clang/lib/Driver/ToolChains/Clang.cpp
@@ -4253,6 +4253,8 @@
         options::OPT_fno_function_sections,
         options::OPT_fdata_sections,
         options::OPT_fno_data_sections,
+        options::OPT_funique_internal_linkage_names,
+        options::OPT_fno_unique_internal_linkage_names,
         options::OPT_funique_section_names,
         options::OPT_fno_unique_section_names,
         options::OPT_mrestrict_it,
@@ -4872,6 +4874,10 @@
                     options::OPT_fno_unique_section_names, true))
     CmdArgs.push_back("-fno-unique-section-names");
 
+  if (Args.hasFlag(options::OPT_funique_internal_linkage_names,
+                   options::OPT_fno_unique_internal_linkage_names, false))
+    CmdArgs.push_back("-funique-internal-linkage-names");
+
   Args.AddLastArg(CmdArgs, options::OPT_finstrument_functions,
                   options::OPT_finstrument_functions_after_inlining,
                   options::OPT_finstrument_function_entry_bare);
Index: clang/lib/Frontend/CompilerInvocation.cpp
===================================================================
--- clang/lib/Frontend/CompilerInvocation.cpp
+++ clang/lib/Frontend/CompilerInvocation.cpp
@@ -957,6 +957,8 @@
   Opts.DataSections = Args.hasArg(OPT_fdata_sections);
   Opts.StackSizeSection = Args.hasArg(OPT_fstack_size_section);
   Opts.UniqueSectionNames = !Args.hasArg(OPT_fno_unique_section_names);
+  Opts.UniqueInternalLinkageNames =
+      Args.hasArg(OPT_funique_internal_linkage_names);
 
   Opts.MergeFunctions = Args.hasArg(OPT_fmerge_functions);
 
Index: clang/test/CodeGen/unique-internal-linkage-names.cpp
===================================================================
--- /dev/null
+++ clang/test/CodeGen/unique-internal-linkage-names.cpp
@@ -0,0 +1,61 @@
+// This test checks if internal linkage symbols get unique names with
+// -funique-internal-linkage-names option.
+// RUN: %clang_cc1 -triple x86_64 -x c++ -S -emit-llvm -o - < %s | FileCheck %s --check-prefix=PLAIN
+// RUN: %clang_cc1 -triple x86_64 -x c++ -S -emit-llvm -funique-internal-linkage-names -o - < %s | FileCheck %s --check-prefix=UNIQUE
+// RUN: %clang_cc1 -triple x86_64 -x c++ -S -emit-llvm -fexperimental-new-pass-manager -funique-internal-linkage-names -o - < %s | FileCheck %s --check-prefix=UNIQUE
+
+static int glob;
+static int foo() {
+  return 0;
+}
+
+int (*bar())() {
+  return foo;
+}
+
+int getGlob() {
+  return glob;
+}
+
+// Function local static variable and anonymous namespace namespace variable.
+namespace {
+int anon_m;
+int getM() {
+  return anon_m;
+}
+} // namespace
+
+int retAnonM() {
+  static int fGlob;
+  return getM() + fGlob;
+}
+
+// Multiversioning symbols
+__attribute__((target("default"))) static int mver() {
+  return 0;
+}
+
+__attribute__((target("sse4.2"))) static int mver() {
+  return 1;
+}
+
+int mver_call() {
+  return mver();
+}
+
+// PLAIN: @_ZL4glob = internal global
+// PLAIN: @_ZZ8retAnonMvE5fGlob = internal global
+// PLAIN: @_ZN12_GLOBAL__N_16anon_mE = internal global
+// PLAIN: define internal i32 @_ZL3foov()
+// PLAIN: define internal i32 @_ZN12_GLOBAL__N_14getMEv
+// PLAIN: define weak_odr i32 ()* @_ZL4mverv.resolver()
+// PLAIN: define internal i32 @_ZL4mverv()
+// PLAIN: define internal i32 @_ZL4mverv.sse4.2()
+// UNIQUE: @_ZL4glob.{{[0-9a-f]+}} = internal global
+// UNIQUE: @_ZZ8retAnonMvE5fGlob.{{[0-9a-f]+}} = internal global
+// UNIQUE: @_ZN12_GLOBAL__N_16anon_mE.{{[0-9a-f]+}} = internal global
+// UNIQUE: define internal i32 @_ZL3foov.{{[0-9a-f]+}}()
+// UNIQUE: define internal i32 @_ZN12_GLOBAL__N_14getMEv.{{[0-9a-f]+}}
+// UNIQUE: define weak_odr i32 ()* @_ZL4mverv.resolver()
+// UNIQUE: define internal i32 @_ZL4mverv.{{[0-9a-f]+}}()
+// UNIQUE: define internal i32 @_ZL4mverv.sse4.2.{{[0-9a-f]+}}
Index: clang/test/Driver/funique-internal-linkage-names.c
===================================================================
--- /dev/null
+++ clang/test/Driver/funique-internal-linkage-names.c
@@ -0,0 +1,4 @@
+// RUN: %clang -### -funique-internal-linkage-names %s -c 2>&1 | FileCheck -check-prefix=CHECK-OPT %s
+// RUN: %clang -### -funique-internal-linkage-names -fno-unique-internal-linkage-names %s -c 2>&1 | FileCheck -check-prefix=CHECK-NOOPT %s
+// CHECK-OPT: "-funique-internal-linkage-names"
+// CHECK-NOOPT-NOT: "-funique-internal-linkage-names"