Index: include/clang/Basic/Sanitizers.h
===================================================================
--- include/clang/Basic/Sanitizers.h
+++ include/clang/Basic/Sanitizers.h
@@ -73,6 +73,9 @@
 /// this group enables.
 SanitizerMask expandSanitizerGroups(SanitizerMask Kinds);
 
+/// Returns the mask of sanitizers which can be used without runtime library.
+SanitizerMask getSanitizersWithNoRequiredRuntime();
+
 }  // end namespace clang
 
 #endif
Index: include/clang/Driver/ToolChain.h
===================================================================
--- include/clang/Driver/ToolChain.h
+++ include/clang/Driver/ToolChain.h
@@ -10,6 +10,7 @@
 #ifndef LLVM_CLANG_DRIVER_TOOLCHAIN_H
 #define LLVM_CLANG_DRIVER_TOOLCHAIN_H
 
+#include "clang/Basic/Sanitizers.h"
 #include "clang/Driver/Action.h"
 #include "clang/Driver/Multilib.h"
 #include "clang/Driver/Types.h"
@@ -348,6 +349,11 @@
   virtual bool
   AddFastMathRuntimeIfAvailable(const llvm::opt::ArgList &Args,
                                 llvm::opt::ArgStringList &CmdArgs) const;
+
+  /// \brief Return sanitizers which are available in this toolchain.
+  virtual SanitizerMask getSupportedSanitizers() const {
+    return getSanitizersWithNoRequiredRuntime();
+  }
 };
 
 } // end namespace driver
Index: lib/Basic/Sanitizers.cpp
===================================================================
--- lib/Basic/Sanitizers.cpp
+++ lib/Basic/Sanitizers.cpp
@@ -56,3 +56,9 @@
 #include "clang/Basic/Sanitizers.def"
   return Kinds;
 }
+
+SanitizerMask clang::getSanitizersWithNoRequiredRuntime() {
+  return SanitizerKind::UndefinedTrap | SanitizerKind::CFI |
+         SanitizerKind::CFICastStrict | SanitizerKind::UnsignedIntegerOverflow |
+         SanitizerKind::LocalBounds;
+}
Index: lib/Driver/MSVCToolChain.cpp
===================================================================
--- lib/Driver/MSVCToolChain.cpp
+++ lib/Driver/MSVCToolChain.cpp
@@ -522,3 +522,12 @@
   }
   return Triple.getTriple();
 }
+
+SanitizerMask MSVCToolChain::getSupportedSanitizers() const {
+  SanitizerMask Res = ToolChain::getSupportedSanitizers();
+  Res |= SanitizerKind::Address;
+  // CFI checks are not implemented for MSVC ABI for now.
+  Res &= ~SanitizerKind::CFI;
+  Res &= ~SanitizerKind::CFICastStrict;
+  return Res;
+}
Index: lib/Driver/SanitizerArgs.cpp
===================================================================
--- lib/Driver/SanitizerArgs.cpp
+++ lib/Driver/SanitizerArgs.cpp
@@ -74,27 +74,6 @@
 /// Sanitizers set.
 static std::string toString(const clang::SanitizerSet &Sanitizers);
 
-static SanitizerMask getToolchainUnsupportedKinds(const ToolChain &TC) {
-  bool IsFreeBSD = TC.getTriple().getOS() == llvm::Triple::FreeBSD;
-  bool IsLinux = TC.getTriple().getOS() == llvm::Triple::Linux;
-  bool IsX86 = TC.getTriple().getArch() == llvm::Triple::x86;
-  bool IsX86_64 = TC.getTriple().getArch() == llvm::Triple::x86_64;
-  bool IsMIPS64 = TC.getTriple().getArch() == llvm::Triple::mips64 ||
-                  TC.getTriple().getArch() == llvm::Triple::mips64el;
-
-  SanitizerMask Unsupported = 0;
-  if (!(IsLinux && (IsX86_64 || IsMIPS64))) {
-    Unsupported |= Memory | DataFlow;
-  }
-  if (!((IsLinux || IsFreeBSD) && (IsX86_64 || IsMIPS64))) {
-    Unsupported |= Thread;
-  }
-  if (!(IsLinux && (IsX86 || IsX86_64))) {
-    Unsupported |= Function;
-  }
-  return Unsupported;
-}
-
 static bool getDefaultBlacklist(const Driver &D, SanitizerMask Kinds,
                                 std::string &BLPath) {
   const char *BlacklistFile = nullptr;
@@ -116,6 +95,17 @@
   return false;
 }
 
+/// Sets group bits for every group that has at least one representative already
+/// enabled in \p Kinds.
+static SanitizerMask setGroupBits(SanitizerMask Kinds) {
+#define SANITIZER(NAME, ID)
+#define SANITIZER_GROUP(NAME, ID, ALIAS)                                       \
+  if (Kinds & SanitizerKind::ID)                                               \
+    Kinds |= SanitizerKind::ID##Group;
+#include "clang/Basic/Sanitizers.def"
+  return Kinds;
+}
+
 bool SanitizerArgs::needsUbsanRt() const {
   return !UbsanTrapOnError && (Sanitizers.Mask & NeedsUbsanRt) &&
          !Sanitizers.has(Address) &&
@@ -162,7 +152,7 @@
   SanitizerMask DiagnosedKinds = 0;  // All Kinds we have diagnosed up to now.
                                      // Used to deduplicate diagnostics.
   SanitizerMask Kinds = 0;
-  SanitizerMask NotSupported = getToolchainUnsupportedKinds(TC);
+  SanitizerMask Supported = setGroupBits(TC.getSupportedSanitizers());
   ToolChain::RTTIMode RTTIMode = TC.getRTTIMode();
 
   const Driver &D = TC.getDriver();
@@ -180,14 +170,14 @@
       // sanitizers in Add are those which have been explicitly enabled.
       // Diagnose them.
       if (SanitizerMask KindsToDiagnose =
-              Add & NotSupported & ~DiagnosedKinds) {
+              Add & ~Supported & ~DiagnosedKinds) {
         // Only diagnose the new kinds.
         std::string Desc = describeSanitizeArg(*I, KindsToDiagnose);
         D.Diag(diag::err_drv_unsupported_opt_for_target)
             << Desc << TC.getTriple().str();
         DiagnosedKinds |= KindsToDiagnose;
       }
-      Add &= ~NotSupported;
+      Add &= Supported;
 
       // Test for -fno-rtti + explicit -fsanitizer=vptr before expanding groups
       // so we don't error out if -fno-rtti and -fsanitize=undefined were
@@ -216,7 +206,7 @@
       Add &= ~AllRemove;
       // Silently discard any unsupported sanitizers implicitly enabled through
       // group expansion.
-      Add &= ~NotSupported;
+      Add &= Supported;
 
       Kinds |= Add;
     } else if (Arg->getOption().matches(options::OPT_fno_sanitize_EQ)) {
Index: lib/Driver/ToolChains.h
===================================================================
--- lib/Driver/ToolChains.h
+++ lib/Driver/ToolChains.h
@@ -474,6 +474,8 @@
   void CheckObjCARC() const override;
 
   bool UseSjLjExceptions() const override;
+
+  SanitizerMask getSupportedSanitizers() const override;
 };
 
 /// DarwinClang - The Darwin toolchain used by Clang.
@@ -616,6 +618,7 @@
 
   bool UseSjLjExceptions() const override;
   bool isPIEDefault() const override;
+  SanitizerMask getSupportedSanitizers() const override;
 protected:
   Tool *buildAssembler() const override;
   Tool *buildLinker() const override;
@@ -679,6 +682,7 @@
   AddClangCXXStdlibIncludeArgs(const llvm::opt::ArgList &DriverArgs,
                                llvm::opt::ArgStringList &CC1Args) const override;
   bool isPIEDefault() const override;
+  SanitizerMask getSupportedSanitizers() const override;
 
   std::string Linker;
   std::vector<std::string> ExtraOpts;
@@ -809,6 +813,7 @@
 
   std::string ComputeEffectiveClangTriple(const llvm::opt::ArgList &Args,
                                           types::ID InputType) const override;
+  SanitizerMask getSupportedSanitizers() const override;
 
 protected:
   void AddSystemIncludeWithSubfolder(const llvm::opt::ArgList &DriverArgs,
Index: lib/Driver/ToolChains.cpp
===================================================================
--- lib/Driver/ToolChains.cpp
+++ lib/Driver/ToolChains.cpp
@@ -403,26 +403,10 @@
 
 
   const SanitizerArgs &Sanitize = getSanitizerArgs();
-
-  if (Sanitize.needsAsanRt()) {
-    if (!isTargetMacOS() && !isTargetIOSSimulator()) {
-      // FIXME: Move this check to SanitizerArgs::filterUnsupportedKinds.
-      getDriver().Diag(diag::err_drv_clang_unsupported_per_platform)
-          << "-fsanitize=address";
-    } else {
-      AddLinkSanitizerLibArgs(Args, CmdArgs, "asan");
-    }
-  }
-
-  if (Sanitize.needsUbsanRt()) {
-    if (!isTargetMacOS() && !isTargetIOSSimulator()) {
-      // FIXME: Move this check to SanitizerArgs::filterUnsupportedKinds.
-      getDriver().Diag(diag::err_drv_clang_unsupported_per_platform)
-          << "-fsanitize=undefined";
-    } else {
-      AddLinkSanitizerLibArgs(Args, CmdArgs, "ubsan");
-    }
-  }
+  if (Sanitize.needsAsanRt())
+    AddLinkSanitizerLibArgs(Args, CmdArgs, "asan");
+  if (Sanitize.needsUbsanRt())
+    AddLinkSanitizerLibArgs(Args, CmdArgs, "ubsan");
 
   // Otherwise link libSystem, then the dynamic runtime library, and finally any
   // target specific static runtime library.
@@ -1101,6 +1085,18 @@
   getDriver().Diag(diag::err_arc_unsupported_on_toolchain);
 }
 
+SanitizerMask Darwin::getSupportedSanitizers() const {
+  SanitizerMask Res = ToolChain::getSupportedSanitizers();
+  if (isTargetMacOS() || isTargetIOSSimulator()) {
+    // ASan and UBSan are available on Mac OS and on iOS simulator.
+    Res |= SanitizerKind::Address;
+    Res |= SanitizerKind::Vptr;
+  }
+  if (isTargetMacOS())
+    Res |= SanitizerKind::SafeStack;
+  return Res;
+}
+
 /// Generic_GCC - A tool chain using the 'gcc' command to perform
 /// all subcommands; this relies on gcc translating the majority of
 /// command line options.
@@ -2741,6 +2737,24 @@
   return getSanitizerArgs().requiresPIE();
 }
 
+SanitizerMask FreeBSD::getSupportedSanitizers() const {
+  const bool IsX86 = getTriple().getArch() == llvm::Triple::x86;
+  const bool IsX86_64 = getTriple().getArch() == llvm::Triple::x86_64;
+  const bool IsMIPS64 = getTriple().getArch() == llvm::Triple::mips64 ||
+                        getTriple().getArch() == llvm::Triple::mips64el;
+  SanitizerMask Res = ToolChain::getSupportedSanitizers();
+  Res |= SanitizerKind::Address;
+  Res |= SanitizerKind::Vptr;
+  if (IsX86_64 || IsMIPS64) {
+    Res |= SanitizerKind::Leak;
+    Res |= SanitizerKind::Thread;
+  }
+  if (IsX86 || IsX86_64) {
+    Res |= SanitizerKind::SafeStack;
+  }
+  return Res;
+}
+
 /// NetBSD - NetBSD tool chain which can call as(1) and ld(1) directly.
 
 NetBSD::NetBSD(const Driver &D, const llvm::Triple& Triple, const ArgList &Args)
@@ -3645,6 +3659,27 @@
   return getSanitizerArgs().requiresPIE();
 }
 
+SanitizerMask Linux::getSupportedSanitizers() const {
+  const bool IsX86 = getTriple().getArch() == llvm::Triple::x86;
+  const bool IsX86_64 = getTriple().getArch() == llvm::Triple::x86_64;
+  const bool IsMIPS64 = getTriple().getArch() == llvm::Triple::mips64 ||
+                        getTriple().getArch() == llvm::Triple::mips64el;
+  SanitizerMask Res = ToolChain::getSupportedSanitizers();
+  Res |= SanitizerKind::Address;
+  Res |= SanitizerKind::Vptr;
+  if (IsX86_64 || IsMIPS64) {
+    Res |= SanitizerKind::DataFlow;
+    Res |= SanitizerKind::Leak;
+    Res |= SanitizerKind::Memory;
+    Res |= SanitizerKind::Thread;
+  }
+  if (IsX86 || IsX86_64) {
+    Res |= SanitizerKind::Function;
+    Res |= SanitizerKind::SafeStack;
+  }
+  return Res;
+}
+
 /// DragonFly - DragonFly tool chain which can call as(1) and ld(1) directly.
 
 DragonFly::DragonFly(const Driver &D, const llvm::Triple& Triple, const ArgList &Args)
Index: test/Driver/asan.c
===================================================================
--- test/Driver/asan.c
+++ test/Driver/asan.c
@@ -1,7 +1,7 @@
-// RUN: %clang     -target i386-unknown-unknown -fsanitize=address %s -S -emit-llvm -o - | FileCheck %s
-// RUN: %clang -O1 -target i386-unknown-unknown -fsanitize=address %s -S -emit-llvm -o - | FileCheck %s
-// RUN: %clang -O2 -target i386-unknown-unknown -fsanitize=address %s -S -emit-llvm -o - | FileCheck %s
-// RUN: %clang -O3 -target i386-unknown-unknown -fsanitize=address %s -S -emit-llvm -o - | FileCheck %s
+// RUN: %clang     -target i386-unknown-linux -fsanitize=address %s -S -emit-llvm -o - | FileCheck %s
+// RUN: %clang -O1 -target i386-unknown-linux -fsanitize=address %s -S -emit-llvm -o - | FileCheck %s
+// RUN: %clang -O2 -target i386-unknown-linux -fsanitize=address %s -S -emit-llvm -o - | FileCheck %s
+// RUN: %clang -O3 -target i386-unknown-linux -fsanitize=address %s -S -emit-llvm -o - | FileCheck %s
 // Verify that -fsanitize=address invokes asan instrumentation.
 
 int foo(int *a) { return *a; }
Index: test/Driver/fsanitize.c
===================================================================
--- test/Driver/fsanitize.c
+++ test/Driver/fsanitize.c
@@ -1,5 +1,5 @@
-// RUN: %clang -target x86_64-linux-gnu -fsanitize=undefined-trap -fsanitize-undefined-trap-on-error %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UNDEFINED-TRAP
-// RUN: %clang -target x86_64-linux-gnu -fsanitize-undefined-trap-on-error -fsanitize=undefined-trap %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UNDEFINED-TRAP
+// RUN: %clang -target x86_64-pc-openbsd -fsanitize=undefined-trap -fsanitize-undefined-trap-on-error %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UNDEFINED-TRAP
+// RUN: %clang -target x86_64-pc-openbsd -fsanitize-undefined-trap-on-error -fsanitize=undefined-trap %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UNDEFINED-TRAP
 // CHECK-UNDEFINED-TRAP: "-fsanitize={{((signed-integer-overflow|integer-divide-by-zero|float-divide-by-zero|shift-base|shift-exponent|unreachable|return|vla-bound|alignment|null|object-size|float-cast-overflow|array-bounds|enum|bool|returns-nonnull-attribute|nonnull-attribute),?){17}"}}
 // CHECK-UNDEFINED-TRAP: "-fsanitize-undefined-trap-on-error"
 
@@ -188,6 +188,12 @@
 // RUN: %clang -target x86_64-apple-darwin10 -fsanitize=function -fsanitize=undefined %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-FSAN-UBSAN-DARWIN
 // CHECK-FSAN-UBSAN-DARWIN: unsupported option '-fsanitize=function' for target 'x86_64-apple-darwin10'
 
+// RUN: %clang -target armv7-apple-ios7 -miphoneos-version-min=7.0 -fsanitize=address %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-ASAN-IOS
+// CHECK-ASAN-IOS: unsupported option '-fsanitize=address' for target 'arm-apple-ios7'
+
+// RUN: %clang -target i386-pc-openbsd -fsanitize=address %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-ASAN-OPENBSD
+// CHECK-ASAN-OPENBSD: unsupported option '-fsanitize=address' for target 'i386-pc-openbsd'
+
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=cfi -c %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-CFI
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=cfi-derived-cast -c %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-CFI-DCAST
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=cfi-unrelated-cast -c %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-CFI-UCAST
Index: test/Driver/rtti-options.cpp
===================================================================
--- test/Driver/rtti-options.cpp
+++ test/Driver/rtti-options.cpp
@@ -16,16 +16,11 @@
 // Make sure we only error/warn once, when trying to enable vptr and
 // undefined and have -fno-rtti
 // RUN: %clang -### -c -fsanitize=undefined -fsanitize=vptr -fno-rtti %s 2>&1 | FileCheck -check-prefix=CHECK-SAN-ERROR -check-prefix=CHECK-OK %s
-
-// RUN: %clang -### -c -target x86_64-scei-ps4 -fsanitize=vptr %s 2>&1 | FileCheck -check-prefix=CHECK-SAN-WARN %s
-// RUN: %clang -### -c -target x86_64-scei-ps4 -fsanitize=vptr -frtti %s 2>&1 | FileCheck -check-prefix=CHECK-OK %s
-// RUN: %clang -### -c -target x86_64-scei-ps4 -fsanitize=vptr -fno-rtti %s 2>&1 | FileCheck -check-prefix=CHECK-SAN-ERROR %s
-// RUN: %clang -### -c -target x86_64-scei-ps4 -fsanitize=undefined -frtti %s 2>&1 | FileCheck -check-prefix=CHECK-OK %s
-// RUN: %clang -### -c -target x86_64-unknown-unknown -fsanitize=vptr %s 2>&1 | FileCheck -check-prefix=CHECK-OK %s
-// RUN: %clang -### -c -target x86_64-unknown-unknown -fsanitize=vptr -frtti %s 2>&1 | FileCheck -check-prefix=CHECK-OK %s
-// RUN: %clang -### -c -target x86_64-unknown-unknown -fsanitize=vptr -fno-rtti %s 2>&1 | FileCheck -check-prefix=CHECK-SAN-ERROR %s
-// RUN: %clang -### -c -target x86_64-unknown-unknown -fsanitize=undefined %s 2>&1 | FileCheck -check-prefix=CHECK-OK %s
-// RUN: %clang -### -c -target x86_64-unknown-unknown -fsanitize=undefined -frtti %s 2>&1 | FileCheck -check-prefix=CHECK-OK %s
+// RUN: %clang -### -c -target x86_64-unknown-linux -fsanitize=vptr %s 2>&1 | FileCheck -check-prefix=CHECK-OK %s
+// RUN: %clang -### -c -target x86_64-unknown-linux -fsanitize=vptr -frtti %s 2>&1 | FileCheck -check-prefix=CHECK-OK %s
+// RUN: %clang -### -c -target x86_64-unknown-linux -fsanitize=vptr -fno-rtti %s 2>&1 | FileCheck -check-prefix=CHECK-SAN-ERROR %s
+// RUN: %clang -### -c -target x86_64-unknown-linux -fsanitize=undefined %s 2>&1 | FileCheck -check-prefix=CHECK-OK %s
+// RUN: %clang -### -c -target x86_64-unknown-linux -fsanitize=undefined -frtti %s 2>&1 | FileCheck -check-prefix=CHECK-OK %s
 
 // Exceptions + no/default rtti
 // RUN: %clang -### -c -target x86_64-scei-ps4 -fcxx-exceptions -fno-rtti %s 2>&1 | FileCheck -check-prefix=CHECK-EXC-ERROR-CXX %s
@@ -51,7 +46,6 @@
 // RUN: %clang -### -c -target x86_64-unknown-unknown %s 2>&1 | FileCheck -check-prefix=CHECK-RTTI %s
 
 // CHECK-UNUSED: warning: argument unused during compilation: '-fcxx-exceptions'
-// CHECK-SAN-WARN: implicitly disabling vptr sanitizer because rtti wasn't enabled
 // CHECK-SAN-ERROR: invalid argument '-fsanitize=vptr' not allowed with '-fno-rtti'
 // CHECK-EXC-WARN: implicitly enabling rtti for exception handling
 // CHECK-EXC-ERROR: invalid argument '-fno-rtti' not allowed with '-fexceptions'