Index: clang/docs/UsersManual.rst
===================================================================
--- clang/docs/UsersManual.rst
+++ clang/docs/UsersManual.rst
@@ -360,6 +360,11 @@
    serialization format is specified, the file will be named
    "foo.opt.<format>".
 
+   On Darwin platforms, if ``-flto`` is used and the file path is not provided,
+   the output file will be chosen according to the linker argument
+   ``-object_path_lto`` if present, or according to the output file specified
+   through ``-o`` otherwise.
+
 .. _opt_foptimization-record-passes:
 
 **-foptimization-record-passes**
Index: clang/lib/Driver/ToolChains/Darwin.cpp
===================================================================
--- clang/lib/Driver/ToolChains/Darwin.cpp
+++ clang/lib/Driver/ToolChains/Darwin.cpp
@@ -427,6 +427,40 @@
   return Args.hasArg(options::OPT_fobjc_link_runtime);
 }
 
+/// Check if the link command contains a path for the lto'd object file.
+static Optional<StringRef> getObjectPathLTO(const ArgList &Args) {
+  bool ExpectPathNext = false;
+  for (Arg *A : Args) {
+    if (ExpectPathNext) {
+      // Expecting -Xlinker <path>, but it's not there.
+      if (!A->getOption().matches(options::OPT_Xlinker))
+        return None;
+      return StringRef(A->getValue(0));
+    }
+
+    bool isWl = A->getOption().matches(options::OPT_Wl_COMMA);
+    bool isXlinker = A->getOption().matches(options::OPT_Xlinker);
+    // We're looking for either:
+    // * -Wl,-object_path_lto,<path>
+    // or
+    // * -Xlinker -object_path_lto -Xlinker <path>
+    if (!isWl && !isXlinker)
+      continue;
+
+    if (!A->containsValue("-object_path_lto"))
+      continue;
+
+    // In case of -Wl, the path is in the same argument.
+    if (isWl)
+      return StringRef(A->getValue(1));
+
+    // In case of -Xlinker, we need to catch the next -Xlinker option and get
+    // the path from there.
+    ExpectPathNext = true;
+  }
+  return None;
+}
+
 void darwin::Linker::ConstructJob(Compilation &C, const JobAction &JA,
                                   const InputInfo &Output,
                                   const InputInfoList &Inputs,
@@ -471,7 +505,11 @@
     CmdArgs.push_back("-mllvm");
 
     SmallString<128> F;
-    F = Output.getFilename();
+    if (Optional<StringRef> Filename = getObjectPathLTO(Args))
+      F = *Filename;
+    else
+      F = Output.getFilename();
+
     F += ".opt.";
     if (const Arg *A =
             Args.getLastArg(options::OPT_fsave_optimization_record_EQ))
Index: clang/test/Driver/darwin-ld.c
===================================================================
--- clang/test/Driver/darwin-ld.c
+++ clang/test/Driver/darwin-ld.c
@@ -315,6 +315,20 @@
 // PASS_REMARKS_OUTPUT: "-mllvm" "-lto-pass-remarks-output" "-mllvm" "foo/bar.out.opt.yaml"
 // PASS_REMARKS_OUTPUT-NOT: -lto-pass-remarks-with-hotness
 
+// Check that when -object_path_lto is used, we're passing the right path to -lto-pass-remarks-output.
+// RUN: %clang -target x86_64-apple-darwin12 %t.o -fsave-optimization-record -### -o foo/bar.out -Wl,-object_path_lto,foo/bar_lto.o 2> %t.log
+// RUN: FileCheck -check-prefix=REMARKS_OBJECT_PATH_LTO_WL %s < %t.log
+// REMARKS_OBJECT_PATH_LTO_WL: "-mllvm" "-lto-pass-remarks-output" "-mllvm" "foo/bar_lto.o.opt.yaml"
+// Also check for -Xlinker.
+// RUN: %clang -target x86_64-apple-darwin12 %t.o -fsave-optimization-record -### -o foo/bar.out -Xlinker -object_path_lto -Xlinker foo/bar_lto.o 2> %t.log
+// RUN: FileCheck -check-prefix=REMARKS_OBJECT_PATH_LTO_XLINKER %s < %t.log
+// REMARKS_OBJECT_PATH_LTO_XLINKER: "-mllvm" "-lto-pass-remarks-output" "-mllvm" "foo/bar_lto.o.opt.yaml"
+// Make sure that we pick the path based on -o if there is no second -Xlinker
+// with the path after -object_path_lto.
+// RUN: %clang -target x86_64-apple-darwin12 %t.o -fsave-optimization-record -### -o foo/bar.out -Xlinker -object_path_lto 2> %t.log
+// RUN: FileCheck -check-prefix=REMARKS_OBJECT_PATH_LTO_XLINKER_MISSING %s < %t.log
+// REMARKS_OBJECT_PATH_LTO_XLINKER_MISSING: "-mllvm" "-lto-pass-remarks-output" "-mllvm" "foo/bar.out.opt.yaml"
+
 // RUN: %clang -target x86_64-apple-darwin12 %t.o -fsave-optimization-record -### 2> %t.log
 // RUN: FileCheck -check-prefix=PASS_REMARKS_OUTPUT_NO_O %s < %t.log
 // PASS_REMARKS_OUTPUT_NO_O: "-mllvm" "-lto-pass-remarks-output" "-mllvm" "a.out.opt.yaml"