Index: lib/Driver/SanitizerArgs.cpp
===================================================================
--- lib/Driver/SanitizerArgs.cpp
+++ lib/Driver/SanitizerArgs.cpp
@@ -85,27 +85,24 @@
 /// Sanitizers set.
 static std::string toString(const clang::SanitizerSet &Sanitizers);
 
-static bool getDefaultBlacklist(const Driver &D, SanitizerMask Kinds,
-                                std::string &BLPath) {
-  const char *BlacklistFile = nullptr;
-  if (Kinds & Address)
-    BlacklistFile = "asan_blacklist.txt";
-  else if (Kinds & Memory)
-    BlacklistFile = "msan_blacklist.txt";
-  else if (Kinds & Thread)
-    BlacklistFile = "tsan_blacklist.txt";
-  else if (Kinds & DataFlow)
-    BlacklistFile = "dfsan_abilist.txt";
-  else if (Kinds & CFI)
-    BlacklistFile = "cfi_blacklist.txt";
-
-  if (BlacklistFile) {
+/// Add default blacklists from the resource directory.
+static void findDefaultBlacklists(const Driver &D, SanitizerMask Kinds,
+                                  std::vector<std::string> &BlacklistFiles) {
+  const std::pair<SanitizerMask, const char *> DefaultBlacklists[] = {
+      {Address, "asan_blacklist.txt"},
+      {Memory, "msan_blacklist.txt"},
+      {Thread, "tsan_blacklist.txt"},
+      {DataFlow, "dfsan_abilist.txt"},
+      {CFI, "cfi_blacklist.txt"}};
+  for (const auto &BL : DefaultBlacklists) {
+    if (!(Kinds & BL.first))
+      continue;
+
     clang::SmallString<64> Path(D.ResourceDir);
-    llvm::sys::path::append(Path, BlacklistFile);
-    BLPath = Path.str();
-    return true;
+    llvm::sys::path::append(Path, BL.second);
+    if (llvm::sys::fs::exists(Path))
+      BlacklistFiles.push_back(Path.str());
   }
-  return false;
 }
 
 /// Sets group bits for every group that has at least one representative already
@@ -382,12 +379,8 @@
   TrappingKinds &= Kinds;
 
   // Setup blacklist files.
-  // Add default blacklist from resource directory.
-  {
-    std::string BLPath;
-    if (getDefaultBlacklist(D, Kinds, BLPath) && llvm::sys::fs::exists(BLPath))
-      BlacklistFiles.push_back(BLPath);
-  }
+  findDefaultBlacklists(D, Kinds, BlacklistFiles);
+
   // Parse -f(no-)sanitize-blacklist options.
   for (const auto *Arg : Args) {
     if (Arg->getOption().matches(options::OPT_fsanitize_blacklist)) {
Index: test/Driver/fsanitize-blacklist.c
===================================================================
--- test/Driver/fsanitize-blacklist.c
+++ test/Driver/fsanitize-blacklist.c
@@ -20,9 +20,20 @@
 // CHECK-BLACKLIST2: -fdepfile-entry={{.*}}.good" "-fdepfile-entry={{.*}}.second
 
 // Check that the default blacklist is not added as an extra dependency.
-// RUN: %clang -target x86_64-linux-gnu -fsanitize=address -resource-dir=%S/Inputs/resource_dir %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-DEFAULT-BLACKLIST --implicit-check-not=fdepfile-entry
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=address -resource-dir=%S/Inputs/resource_dir %s -### &> %t.cc1_asan
+// RUN: FileCheck %s --check-prefix=CHECK-DEFAULT-BLACKLIST --implicit-check-not=fdepfile-entry -input-file %t.cc1_asan
 // CHECK-DEFAULT-BLACKLIST: -fsanitize-blacklist={{.*}}asan_blacklist.txt
 
+// Check that default blacklists are not added unless the matching sanitizer is
+// enabled, even if the blacklist exists.
+// RUN: FileCheck %s --implicit-check-not=cfi_blacklist.txt -input-file %t.cc1_asan
+
+// Check that we can add multiple default blacklists if the matching sanitizers
+// are enabled.
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=address,cfi -flto -fvisibility=hidden -resource-dir=%S/Inputs/resource_dir %s -### 2>&1 | FileCheck %s --check-prefix=MULTIPLE-DEFAULT-BLACKLISTS
+// MULTIPLE-DEFAULT-BLACKLISTS-DAG: -fsanitize-blacklist={{.*}}asan_blacklist.txt
+// MULTIPLE-DEFAULT-BLACKLISTS-DAG: -fsanitize-blacklist={{.*}}cfi_blacklist.txt
+
 // Ignore -fsanitize-blacklist flag if there is no -fsanitize flag.
 // RUN: %clang -target x86_64-linux-gnu -fsanitize-blacklist=%t.good %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-NO-SANITIZE --check-prefix=DELIMITERS
 // CHECK-NO-SANITIZE-NOT: -fsanitize-blacklist