Index: include/clang/Driver/Options.td
===================================================================
--- include/clang/Driver/Options.td
+++ include/clang/Driver/Options.td
@@ -519,6 +519,9 @@
 def fno_sanitize_blacklist : Flag<["-"], "fno-sanitize-blacklist">,
                              Group<f_clang_Group>,
                              HelpText<"Don't use blacklist file for sanitizers">;
+def fsanitize_coverage : Joined<["-"], "fsanitize-coverage=">,
+                                        Group<f_clang_Group>, Flags<[CC1Option]>,
+                                        HelpText<"Enable coverage instrumentation for Sanitizers">;
 def fsanitize_memory_track_origins_EQ : Joined<["-"], "fsanitize-memory-track-origins=">,
                                         Group<f_clang_Group>, Flags<[CC1Option]>,
                                         HelpText<"Enable origins tracking in MemorySanitizer">;
Index: include/clang/Driver/SanitizerArgs.h
===================================================================
--- include/clang/Driver/SanitizerArgs.h
+++ include/clang/Driver/SanitizerArgs.h
@@ -48,6 +48,7 @@
   unsigned Kind;
 
   std::string BlacklistFile;
+  int SanitizeCoverage;
   int MsanTrackOrigins;
   int AsanFieldPadding;
   bool AsanZeroBaseShadow;
Index: include/clang/Frontend/CodeGenOptions.def
===================================================================
--- include/clang/Frontend/CodeGenOptions.def
+++ include/clang/Frontend/CodeGenOptions.def
@@ -107,6 +107,7 @@
                                                  ///< offset in AddressSanitizer.
 CODEGENOPT(SanitizeMemoryTrackOrigins, 2, 0) ///< Enable tracking origins in
                                              ///< MemorySanitizer
+CODEGENOPT(SanitizeCoverage, 3, 0) ///< Enable sanitizer coverage instrumentation.
 CODEGENOPT(SanitizeUndefinedTrapOnError, 1, 0) ///< Set on
                                                /// -fsanitize-undefined-trap-on-error
 CODEGENOPT(SimplifyLibCalls  , 1, 1) ///< Set when -fbuiltin is enabled.
Index: lib/CodeGen/BackendUtil.cpp
===================================================================
--- lib/CodeGen/BackendUtil.cpp
+++ lib/CodeGen/BackendUtil.cpp
@@ -179,6 +179,14 @@
   PM.add(createBoundsCheckingPass());
 }
 
+static void addSanitizerCoveragePass(const PassManagerBuilder &Builder,
+                                     PassManagerBase &PM) {
+  const PassManagerBuilderWrapper &BuilderWrapper =
+      static_cast<const PassManagerBuilderWrapper&>(Builder);
+  const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
+  PM.add(createSanitizerCoverageModulePass(CGOpts.SanitizeCoverage));
+}
+
 static void addAddressSanitizerPasses(const PassManagerBuilder &Builder,
                                       PassManagerBase &PM) {
   PM.add(createAddressSanitizerFunctionPass());
@@ -274,6 +282,13 @@
                            addBoundsCheckingPass);
   }
 
+  if (CodeGenOpts.SanitizeCoverage) {
+    PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
+                           addSanitizerCoveragePass);
+    PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
+                           addSanitizerCoveragePass);
+  }
+
   if (LangOpts.Sanitize.Address) {
     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
                            addAddressSanitizerPasses);
Index: lib/Driver/SanitizerArgs.cpp
===================================================================
--- lib/Driver/SanitizerArgs.cpp
+++ lib/Driver/SanitizerArgs.cpp
@@ -24,6 +24,7 @@
 void SanitizerArgs::clear() {
   Kind = 0;
   BlacklistFile = "";
+  SanitizeCoverage = 0;
   MsanTrackOrigins = 0;
   AsanFieldPadding = 0;
   AsanZeroBaseShadow = false;
@@ -159,6 +160,17 @@
     }
   }
 
+  // Parse -fsanitize-coverage=N
+  if (NeedsAsan) {  // Currently asan is required.
+    if (Arg *A = Args.getLastArg(options::OPT_fsanitize_coverage)) {
+      StringRef S = A->getValue();
+      // Legal values are 0..4.
+      if (S.getAsInteger(0, SanitizeCoverage) || SanitizeCoverage < 0 ||
+          SanitizeCoverage > 4)
+        D.Diag(diag::err_drv_invalid_value) << A->getAsString(Args) << S;
+    }
+  }
+
   if (NeedsAsan) {
     AsanSharedRuntime =
         Args.hasArg(options::OPT_shared_libasan) ||
@@ -219,6 +231,9 @@
   if (AsanFieldPadding)
     CmdArgs.push_back(Args.MakeArgString("-fsanitize-address-field-padding=" +
                                          llvm::utostr(AsanFieldPadding)));
+  if (SanitizeCoverage)
+    CmdArgs.push_back(Args.MakeArgString("-fsanitize-coverage=" +
+                                         llvm::utostr(SanitizeCoverage)));
   // Workaround for PR16386.
   if (needsMsanRt())
     CmdArgs.push_back(Args.MakeArgString("-fno-assume-sane-operator-new"));
Index: lib/Frontend/CompilerInvocation.cpp
===================================================================
--- lib/Frontend/CompilerInvocation.cpp
+++ lib/Frontend/CompilerInvocation.cpp
@@ -488,6 +488,8 @@
   Opts.CompressDebugSections = Args.hasArg(OPT_compress_debug_sections);
   Opts.DebugCompilationDir = Args.getLastArgValue(OPT_fdebug_compilation_dir);
   Opts.LinkBitcodeFile = Args.getLastArgValue(OPT_mlink_bitcode_file);
+  Opts.SanitizeCoverage =
+      getLastArgIntValue(Args, OPT_fsanitize_coverage, 0, Diags);
   Opts.SanitizeMemoryTrackOrigins =
       getLastArgIntValue(Args, OPT_fsanitize_memory_track_origins_EQ, 0, Diags);
   Opts.SanitizeUndefinedTrapOnError =
Index: test/Driver/fsanitize.c
===================================================================
--- test/Driver/fsanitize.c
+++ test/Driver/fsanitize.c
@@ -80,6 +80,16 @@
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=memory -fsanitize-memory-track-origins=3 -pie %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-TRACK-ORIGINS-3
 // CHECK-TRACK-ORIGINS-3: error: invalid value '3' in '-fsanitize-memory-track-origins=3'
 
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=address -fsanitize-coverage=0 %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-SANITIZE-COVERAGE-0
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=address                       %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-SANITIZE-COVERAGE-0
+// CHECK-SANITIZE-COVERAGE-0-NOT: fsanitize-coverage
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=address -fsanitize-coverage=1 %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-SANITIZE-COVERAGE-1
+// CHECK-SANITIZE-COVERAGE-1: fsanitize-coverage=1
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=address -fsanitize-coverage=4 %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-SANITIZE-COVERAGE-4
+// CHECK-SANITIZE-COVERAGE-4: fsanitize-coverage=4
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=address -fsanitize-coverage=5 %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-SANITIZE-COVERAGE-5
+// CHECK-SANITIZE-COVERAGE-5: error: invalid value '5' in '-fsanitize-coverage=5'
+
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=address -fsanitize-address-field-padding=0 %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-ASAN-FIELD-PADDING-0
 // CHECK-ASAN-FIELD-PADDING-0-NOT: -fsanitize-address-field-padding
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=address -fsanitize-address-field-padding=1 %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-ASAN-FIELD-PADDING-1