Index: cfe/trunk/include/clang/Basic/DiagnosticDriverKinds.td
===================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticDriverKinds.td
+++ cfe/trunk/include/clang/Basic/DiagnosticDriverKinds.td
@@ -160,6 +160,12 @@
   InGroup<DiagGroup<"missing-sysroot">>;
 def warn_debug_compression_unavailable : Warning<"cannot compress debug sections (zlib not installed)">,
   InGroup<DiagGroup<"debug-compression-unavailable">>;
+def warn_drv_enabling_rtti_with_exceptions : Warning<
+  "implicitly enabling rtti for exception handling">,
+  InGroup<DiagGroup<"rtti-for-exceptions">>;
+def warn_drv_disabling_vptr_no_rtti_default : Warning<
+  "implicitly disabling vptr sanitizer because rtti wasn't enabled">,
+  InGroup<DiagGroup<"auto-disable-vptr-sanitizer">>;
 
 def note_drv_command_failed_diag_msg : Note<
   "diagnostic msg: %0">;
Index: cfe/trunk/lib/Driver/Tools.cpp
===================================================================
--- cfe/trunk/lib/Driver/Tools.cpp
+++ cfe/trunk/lib/Driver/Tools.cpp
@@ -3956,20 +3956,48 @@
                    false))
     CmdArgs.push_back("-fno-elide-constructors");
 
-  // -frtti is default.
-  if (!Args.hasFlag(options::OPT_frtti, options::OPT_fno_rtti) ||
+  // -frtti is default, except for the PS4 CPU.
+  if (!Args.hasFlag(options::OPT_frtti, options::OPT_fno_rtti,
+                    !Triple.isPS4CPU()) ||
       KernelOrKext) {
-    CmdArgs.push_back("-fno-rtti");
+    bool RTTIEnabled = false;
+    Arg *NoRTTIArg = Args.getLastArg(
+        options::OPT_mkernel, options::OPT_fapple_kext, options::OPT_fno_rtti);
+
+    // PS4 requires rtti when exceptions are enabled. If -fno-rtti was
+    // explicitly passed, error out. Otherwise enable rtti and emit a
+    // warning.
+    if (Triple.isPS4CPU()) {
+      if (Arg *A = Args.getLastArg(options::OPT_fcxx_exceptions,
+                                   options::OPT_fexceptions)) {
+        if (NoRTTIArg)
+          D.Diag(diag::err_drv_argument_not_allowed_with)
+              << NoRTTIArg->getAsString(Args) << A->getAsString(Args);
+        else {
+          RTTIEnabled = true;
+          D.Diag(diag::warn_drv_enabling_rtti_with_exceptions);
+        }
+      }
+    }
 
     // -fno-rtti cannot usefully be combined with -fsanitize=vptr.
     if (Sanitize.sanitizesVptr()) {
-      std::string NoRttiArg =
-        Args.getLastArg(options::OPT_mkernel,
-                        options::OPT_fapple_kext,
-                        options::OPT_fno_rtti)->getAsString(Args);
-      D.Diag(diag::err_drv_argument_not_allowed_with)
-        << "-fsanitize=vptr" << NoRttiArg;
+      // If rtti was explicitly disabled and the vptr sanitizer is on, error
+      // out. Otherwise, warn that vptr will be disabled unless -frtti is
+      // passed.
+      if (NoRTTIArg) {
+        D.Diag(diag::err_drv_argument_not_allowed_with)
+            << "-fsanitize=vptr" << NoRTTIArg->getAsString(Args);
+      } else {
+        D.Diag(diag::warn_drv_disabling_vptr_no_rtti_default);
+        // All sanitizer switches have been pushed. This -fno-sanitize
+        // will override any -fsanitize={vptr,undefined} passed before it.
+        CmdArgs.push_back("-fno-sanitize=vptr");
+      }
     }
+
+    if (!RTTIEnabled)
+      CmdArgs.push_back("-fno-rtti");
   }
 
   // -fshort-enums=0 is default for all architectures except Hexagon.
Index: cfe/trunk/test/Driver/rtti-options.cpp
===================================================================
--- cfe/trunk/test/Driver/rtti-options.cpp
+++ cfe/trunk/test/Driver/rtti-options.cpp
@@ -0,0 +1,52 @@
+// Check that we emit warnings/errors for different combinations of
+// exceptions, rtti, and vptr sanitizer flags when targetting the PS4.
+// No warnings/errors should be emitted for unknown, except if combining
+// the vptr sanitizer with -fno-rtti
+
+// -fsanitize=vptr
+// 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 %s 2>&1 | FileCheck -check-prefix=CHECK-SAN-WARN %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-scei-ps4 -fsanitize=undefined -fno-rtti %s 2>&1 | FileCheck -check-prefix=CHECK-SAN-ERROR %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-unknown -fsanitize=undefined -fno-rtti %s 2>&1 | FileCheck -check-prefix=CHECK-SAN-ERROR %s
+
+// Exceptions + no/default rtti
+// RUN: %clang -### -c -target x86_64-scei-ps4 -fexceptions -fno-rtti %s 2>&1 | FileCheck -check-prefix=CHECK-EXC-ERROR %s
+// RUN: %clang -### -c -target x86_64-scei-ps4 -fcxx-exceptions -fno-rtti %s 2>&1 | FileCheck -check-prefix=CHECK-EXC-ERROR-CXX %s
+// RUN: %clang -### -c -target x86_64-scei-ps4 -fexceptions %s 2>&1 | FileCheck -check-prefix=CHECK-EXC-WARN %s
+// RUN: %clang -### -c -target x86_64-scei-ps4 -fcxx-exceptions %s 2>&1 | FileCheck -check-prefix=CHECK-EXC-WARN %s
+// RUN: %clang -### -c -target x86_64-unknown-unknown -fexceptions -fno-rtti %s 2>&1 | FileCheck -check-prefix=CHECK-OK %s
+// RUN: %clang -### -c -target x86_64-unknown-unknown -fcxx-exceptions -fno-rtti %s 2>&1 | FileCheck -check-prefix=CHECK-OK %s
+// RUN: %clang -### -c -target x86_64-unknown-unknown -fexceptions %s 2>&1 | FileCheck -check-prefix=CHECK-OK %s
+// RUN: %clang -### -c -target x86_64-unknown-unknown -fcxx-exceptions %s 2>&1 | FileCheck -check-prefix=CHECK-OK %s
+
+// -frtti + exceptions
+// RUN: %clang -### -c -target x86_64-scei-ps4 -fexceptions -frtti %s 2>&1 | FileCheck -check-prefix=CHECK-OK %s
+// RUN: %clang -### -c -target x86_64-scei-ps4 -fcxx-exceptions -frtti %s 2>&1 | FileCheck -check-prefix=CHECK-OK %s
+// RUN: %clang -### -c -target x86_64-unknown-unknown -fexceptions -frtti %s 2>&1 | FileCheck -check-prefix=CHECK-OK %s
+// RUN: %clang -### -c -target x86_64-unknown-unknown -fcxx-exceptions -frtti %s 2>&1 | FileCheck -check-prefix=CHECK-OK %s
+
+// -f{no-,}rtti/default
+// RUN: %clang -### -c -target x86_64-scei-ps4 -frtti %s 2>&1 | FileCheck -check-prefix=CHECK-RTTI %s
+// RUN: %clang -### -c -target x86_64-scei-ps4 -fno-rtti %s 2>&1 | FileCheck -check-prefix=CHECK-NO-RTTI %s
+// RUN: %clang -### -c -target x86_64-scei-ps4 %s 2>&1 | FileCheck -check-prefix=CHECK-NO-RTTI %s
+// RUN: %clang -### -c -target x86_64-unknown-unknown -frtti %s 2>&1 | FileCheck -check-prefix=CHECK-RTTI %s
+// RUN: %clang -### -c -target x86_64-unknown-unknown -fno-rtti %s 2>&1 | FileCheck -check-prefix=CHECK-NO-RTTI %s
+// RUN: %clang -### -c -target x86_64-unknown-unknown %s 2>&1 | FileCheck -check-prefix=CHECK-RTTI %s
+
+// 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'
+// CHECK-EXC-ERROR-CXX: invalid argument '-fno-rtti' not allowed with '-fcxx-exceptions'
+// CHECK-RTTI-NOT: "-fno-rtti"
+// CHECK-NO-RTTI-NOT: "-frtti"
+
+// CHECK-OK-NOT: {{warning:|error:}}