Introduce -fsanitize-trap= flag.

[pcc]

Summary

This flag controls whether a given sanitizer traps upon detecting
an error. It currently only supports UBSan. The existing flag
-fsanitize-undefined-trap-on-error has been made an alias of
-fsanitize-trap=undefined.

This change also cleans up some awkward behavior around the combination
of -fsanitize-trap=undefined and -fsanitize=undefined. Previously we
would reject command lines containing the combination of these two flags,
as -fsanitize=vptr is not compatible with trapping. This required the
creation of -fsanitize=undefined-trap, which excluded -fsanitize=vptr
(and -fsanitize=function, but this seems like an oversight).

Now, -fsanitize=undefined is an alias for -fsanitize=undefined-trap,
and if -fsanitize-trap=undefined is specified, we treat -fsanitize=vptr
as an "unsupported" flag, which means that we error out if the flag is
specified explicitly, but implicitly disable it if the flag was implied
by -fsanitize=undefined.

[rsmith]

docs/UsersManual.rst

1112

Missing 'the' before -fsanitize=?

1113–1115

I think this description will leave people wondering why we have a per-sanitizer trap flag rather than a global flag. It'd be good to extend this description with the CFI case.

1118

It's probably better to refer to the group as "`undefined" rather than "UndefinedBehaviorSanitizer", for symmetry with "vptr`".

lib/CodeGen/CGExpr.cpp

2306–2315

The differing style in these two cases is strange. Please pick one or the other and apply it to both the Recover and the Trap cases.

lib/Driver/SanitizerArgs.cpp

210

I think this should be TrappingKinds & Vptr. If I write -fsanitize-trap=undefined -fsanitize=vptr -fno-sanitize-trap=vptr, I think you'll currently mark vptr as unavailable, but it seems reasonable to support that case.

[samsonov]

docs/UsersManual.rst

973–975

"deprecated alias"

1110

Please move it next to -fsanitize-recover=.

1117

Do you think we should allow other trapping sanitizers (like local-bounds) here? Or you plan to do it in subsequent patches?

include/clang/Driver/Options.td

526

Please move next to fsanitize_recover

lib/Driver/SanitizerArgs.cpp

37

Could we use smth. like getSanitizersWithNoRequiredRuntime() from http://reviews.llvm.org/D10467 instead (if we decide to allow -fsanitize-trap=` for other checks)?

37

I'd prefer to not use UndefinedGroup here, and instead add special case for Vptr to the loop iterating over -fsanitize-trap= arguments. E.g. see how we handle special-case for vptr+RTTI in the main loop in SanitizerArgs constructor (not that it's elegant, it's just... more literal).

528–530

if (!TrapSanitizers.empty())

[pcc]

• Address review comments

docs/UsersManual.rst

973–975

Done

1110

Done

1112

Added

1113–1115

The CFI case will be implemented in a separate patch, which will include a documentation update here. For now we do not support -fsanitize-trap=cfi.

1117

Added.

1118

Done

include/clang/Driver/Options.td

526

Done

lib/CodeGen/CGExpr.cpp

2306–2315

Done

lib/Driver/SanitizerArgs.cpp

37

Could we use smth. like getSanitizersWithNoRequiredRuntime() from http://reviews.llvm.org/D10467 instead (if we decide to allow -fsanitize-trap=` for other checks)?

Most likely, I'll do that once your change lands.

I'd prefer to not use UndefinedGroup here, and instead add special case for Vptr to the loop iterating over -fsanitize-trap= arguments.

I don't see how that would work. I think we'd always need groups in the thing we mask against, otherwise we'd incorrectly diagnose things like -fsanitize-trap=undefined due to the presence of the group. Seems like the setGroupBits thing you added in D10467 does what I want?

210

Done

528–530

Done

[samsonov]

lib/CodeGen/CGExpr.cpp

2306

Should we clarify this behavior in the docs?
We can also handle this case in the driver, so that frontend can assert that each sanitizer check is listed in at most one of -fsanitize-recover= and -fsanitize-trap= lists. (i.e. intersection of SanitizeTrap and SanitizeRecover is empty).

Another interesting question is handling the relative order of -fsanitize-trap= and -fsanitize-recover= flags. Now we parse them completely independently, but this may not be the best solution. Consider global

CFLAGS='-fsanitize=undefined -fsanitize-trap=undefined'

and now I want to compile a special program, and enable recovery for alignment issues. Using

clang++ $(CFLAGS) -fsanitize-recover=alignment a.cc

wouldn't work, I would have to write

clang++ $(CFLAGS) -fno-sanitize-trap=alignment -fsanitize-recover=alignment a.cc

Do you think we should instead parse -fsanitize-trap and -fsanitize-recover in a single pass, and maintain the recovery setting for each sanitizer kind to be one of

• diagnosed, recoverable
• diagnosed, unrecoverable/fatal
• undiagnosed, trapping.

?

lib/Driver/SanitizerArgs.cpp

37

Yep, let's use setGroupBits. Specifying the groups here manually is error-prone - one can easily forget to change this part if Sanitizers.def is re-orrganized.

503

Note that you can also strip out sanitizers which were not enabled eventually from here

TrappingKinds &= Kinds;

as we do for recoverable sanitizers.

[pcc]

• Fix disablement logic

[pcc]

• Document -fsanitize-trap precedence over -fsanitize-recover
• Filter TrappingKinds based on Kinds

lib/CodeGen/CGExpr.cpp

2306

Should we clarify this behavior in the docs?

Yes, done.

Do you think we should instead parse -fsanitize-trap and -fsanitize-recover in a single pass

The logic around parsing these flags is already too complicated and I would be against making it more complex than it already is. I would prefer to solve this problem with documentation.

lib/Driver/SanitizerArgs.cpp

503

Done

[samsonov]

include/clang/Driver/Options.td

565

Add some HelpText

lib/Driver/SanitizerArgs.cpp

37

If you're happy with http://reviews.llvm.org/D10467, we can submit that one first, and add setGroupBits to this patch. Or steal setGroupBits part from there if you want this patch to go in first.

210

We already have NotAllowedWithTrap mask. I think we should use it, and probably split diagnosing the sanitizers unsupported because they cannot trap, and those that are not supported by the toolchain. You already do some of the former in parseSanitizeTrapArgs above, I think we should handle vptr in that function as well somehow.

[pcc]

• Address reviewer comments

include/clang/Driver/Options.td

565

Done

lib/Driver/SanitizerArgs.cpp

37

Done. Per offline discussion I've moved setGroupBits to this patch.

210

We already have NotAllowedWithTrap mask. I think we should use it

Done.

and probably split diagnosing the sanitizers unsupported because they cannot trap, and those that are not supported by the toolchain. You already do some of the former in parseSanitizeTrapArgs above, I think we should handle vptr in that function as well somehow.

Not really sure how that would work. We only know which sanitizers to forbid once we have looked at all -fsanitize-trap arguments. At the very least it makes the code easier to read if all unsupported sanitizer diagnostics are done in a single place. (This would have fit much better into the original design from D1990 with an extra clause in filterUnsupportedKinds; oh well.)

[samsonov]

I'm mostly happy with this patch. Accepting it, so that you can land it without yet another round of review, but please consider addressing the comments below.

Thank you for doing this!

lib/Driver/SanitizerArgs.cpp

147

if (SanitizerMask InvalidValues = Add & ~TrappingSupportedWithGroups) {
  SanitizerSet S;
  S.Mask = InvalidValues;
  //....
}

165

TrapRemove |= expandSanitizerGroups(UndefinedGroup);

227

I don't think this is right. Suppose -fsanitize=vptr is not supported on target foo (by corresponding toolchain). Then

clang -target foo -fsanitize=vptr a.cc

would produce confusing

"-fsanitize=vptr" is not allowed with "-fsanitize-trap=undefined"

I think you would need separate clause for that

if (SanitizerMask KindsToDiagnose = Add & TrappingKinds & NotAllowedWithTrap & ~DiagnosedKinds) {
  std::string Desc = describeSanitizeArg(*I, KindsToDiagnose);
  D.Diag(diag::err_drv_argument_not_allowed_with) << Desc << lastTrapArgumentForMask(KindsToDiagnose);
  DiagnosedKinds |= KindsToDiagnose;
}

[pcc]

lib/Driver/SanitizerArgs.cpp

147

Done

165

Done

227

Done. (We know that the second argument to the diagnostic can only ever be "-fsanitize-trap=undefined", so I've hard coded that for now.)

docs/UsersManual.rst

**-f[no-]sanitize=check1,check2,...**
    -  .. _opt_fsanitize_undefined:
 
       ``-fsanitize=undefined``: Fast and compatible undefined behavior
       checker. Enables the undefined behavior checks that have small
       runtime cost and no impact on address space layout or ABI. This
       includes all of the checks listed below other than
       ``unsigned-integer-overflow``.
 
-   -  ``-fsanitize=undefined-trap``: This includes all sanitizers
-      included by ``-fsanitize=undefined``, except those that require
-      runtime support. This group of sanitizers is intended to be
-      used in conjunction with the ``-fsanitize-undefined-trap-on-error``
-      flag. This includes all of the checks listed below other than
-      ``unsigned-integer-overflow`` and ``vptr``.
+   -  ``-fsanitize=undefined-trap``: This is a deprecated alias for
+      ``-fsanitize=undefined``.
+
    -  ``-fsanitize=dataflow``: :doc:`DataFlowSanitizer`, a general data
       flow analysis.
    -  ``-fsanitize=cfi``: :doc:`control flow integrity <ControlFlowIntegrity>`
       checks. Implies ``-flto``.
    -  ``-fsanitize=safe-stack``: :doc:`safe stack <SafeStack>`
       protection against stack-based memory corruption errors.
 
    The following more fine-grained checks are also available:
-  ``-fsanitize-memory-track-origins[=level]``: Enables origin tracking in
       1.5x-2x.
 
       Possible values for level are 0 (off), 1, 2 (default). Level 2
       adds more sections to MemorySanitizer reports describing the
       order of memory stores the uninitialized value went
       through. This mode may use extra memory in programs that copy
       uninitialized memory a lot.
 
-   Extra features of UndefinedBehaviorSanitizer:
-
-   -  ``-fsanitize-undefined-trap-on-error``: Causes traps to be emitted
-      rather than calls to runtime libraries when a problem is detected.
-      This option is intended for use in cases where the sanitizer runtime
-      cannot be used (for instance, when building libc or a kernel module).
-      This is only compatible with the sanitizers in the ``undefined-trap``
-      group.
-
    The ``-fsanitize=`` argument must also be provided when linking, in
    order to link to the appropriate runtime library. When using
    ``-fsanitize=vptr`` (or a group that includes it, such as
    ``-fsanitize=undefined``) with a C++ program, the link must be
    performed by ``clang++``, not ``clang``, in order to link against the
    C++-specific parts of the runtime library.
 
    It is not possible to combine more than one of the ``-fsanitize=address``,
    ``-fsanitize=thread``, and ``-fsanitize=memory`` checkers in the same
    program. The ``-fsanitize=undefined`` checks can only be combined with
    ``-fsanitize=address``.
 
 **-f[no-]sanitize-recover=check1,check2,...**
 
    Controls which checks enabled by ``-fsanitize=`` flag are non-fatal.
    If the check is fatal, program will halt after the first error
    of this kind is detected and error report is printed.
 
    By default, non-fatal checks are those enabled by UndefinedBehaviorSanitizer,
    except for ``-fsanitize=return`` and ``-fsanitize=unreachable``. Some
    sanitizers (e.g. :doc:`AddressSanitizer`) may not support recovery,
    and always crash the program after the issue is detected.
 
+**-f[no-]sanitize-trap=check1,check2,...**
+
+   Controls which checks enabled by the ``-fsanitize=`` flag trap. This
+   option is intended for use in cases where the sanitizer runtime cannot
+   be used (for instance, when building libc or a kernel module), or where
+   the binary size increase caused by the sanitizer runtime is a concern.
+
+   This flag is only compatible with ``local-bounds``,
+   ``unsigned-integer-overflow`` and sanitizers in the ``undefined``
+   group other than ``vptr``. If this flag is supplied together with
+   ``-fsanitize=undefined``, the ``vptr`` sanitizer will be implicitly
+   disabled.
+
 **-f[no-]sanitize-coverage=[type,features,...]**
 
    Enable simple code coverage in addition to certain sanitizers.
    See :doc:`SanitizerCoverage` for more details.
 
+.. option:: -fsanitize-undefined-trap-on-error
+
+   Deprecated alias for ``-fsanitize-trap=undefined``.
+
 .. option:: -fno-assume-sane-operator-new
 
    Don't assume that the C++'s new operator is sane.
 
    This option tells the compiler to do not assume that C++'s global
    new operator will always return a pointer that does not alias any
    other pointer when the function returns.
 
 .. option:: -ftrap-function=[name]
 
    Instruct code generator to emit a function call to the specified
    function name for ``__builtin_trap()``.
 

include/clang/Basic/Sanitizers.def

 SANITIZER("cfi-nvcall", CFINVCall)
 SANITIZER("cfi-vcall", CFIVCall)
 SANITIZER_GROUP("cfi", CFI,
                 CFIDerivedCast | CFIUnrelatedCast | CFINVCall | CFIVCall)
 
 // Safe Stack
 SANITIZER("safe-stack", SafeStack)
 
-// -fsanitize=undefined-trap includes sanitizers from -fsanitize=undefined
-// that can be used without runtime support, generally by providing extra
-// -fsanitize-undefined-trap-on-error flag.
-SANITIZER_GROUP("undefined-trap", UndefinedTrap,
+// -fsanitize=undefined includes all the sanitizers which have low overhead, no
+// ABI or address space layout implications, and only catch undefined behavior.
+SANITIZER_GROUP("undefined", Undefined,
                 Alignment | Bool | ArrayBounds | Enum | FloatCastOverflow |
                     FloatDivideByZero | IntegerDivideByZero | NonnullAttribute |
                     Null | ObjectSize | Return | ReturnsNonnullAttribute |
-                    Shift | SignedIntegerOverflow | Unreachable | VLABound)
+                    Shift | SignedIntegerOverflow | Unreachable | VLABound |
+                    Function | Vptr)
 
-// -fsanitize=undefined includes all the sanitizers which have low overhead, no
-// ABI or address space layout implications, and only catch undefined behavior.
-SANITIZER_GROUP("undefined", Undefined, UndefinedTrap | Function | Vptr)
+// -fsanitize=undefined-trap is an alias for -fsanitize=undefined.
+SANITIZER_GROUP("undefined-trap", UndefinedTrap, Undefined)
 
 SANITIZER_GROUP("integer", Integer,
                 SignedIntegerOverflow | UnsignedIntegerOverflow | Shift |
                 IntegerDivideByZero)
 
 SANITIZER("local-bounds", LocalBounds)
 SANITIZER_GROUP("bounds", Bounds, ArrayBounds | LocalBounds)
 
 // Magic group, containing all sanitizers. For example, "-fno-sanitize=all"
 // can be used to disable all the sanitizers.
 SANITIZER_GROUP("all", All, ~0ULL)
 
 #undef SANITIZER
 #undef SANITIZER_GROUP

include/clang/Driver/Options.td

 def fbracket_depth_EQ : Joined<["-"], "fbracket-depth=">, Group<f_Group>;
 def fsignaling_math : Flag<["-"], "fsignaling-math">, Group<f_Group>;
 def fno_signaling_math : Flag<["-"], "fno-signaling-math">, Group<f_Group>;
 def fsanitize_EQ : CommaJoined<["-"], "fsanitize=">, Group<f_clang_Group>,
                    Flags<[CC1Option, CoreOption]>, MetaVarName<"<check>">,
                    HelpText<"Turn on runtime checks for various forms of undefined "
                             "or suspicious behavior. See user manual for available checks ">;
 def fno_sanitize_EQ : CommaJoined<["-"], "fno-sanitize=">, Group<f_clang_Group>;
 def fsanitize_blacklist : Joined<["-"], "fsanitize-blacklist=">,
                           Group<f_clang_Group>, Flags<[CC1Option, CoreOption]>,
                           HelpText<"Path to blacklist file for sanitizers">;
 def fno_sanitize_blacklist : Flag<["-"], "fno-sanitize-blacklist">,
                              Group<f_clang_Group>,
                              HelpText<"Don't use blacklist file for sanitizers">;
 def fsanitize_coverage
     : CommaJoined<["-"], "fsanitize-coverage=">,
       Group<f_clang_Group>, Flags<[CoreOption]>,

 def fsanitize_recover_EQ : CommaJoined<["-"], "fsanitize-recover=">,
                            Group<f_clang_Group>,
                            Flags<[CC1Option]>,
                            HelpText<"Enable recovery for specified sanitizers">;
 def fno_sanitize_recover_EQ
     : CommaJoined<["-"], "fno-sanitize-recover=">,
       Group<f_clang_Group>,
       HelpText<"Disable recovery for specified sanitizers">;
+def fsanitize_trap_EQ : CommaJoined<["-"], "fsanitize-trap=">, Group<f_clang_Group>,
+                        Flags<[CC1Option, CoreOption]>;
+def fno_sanitize_trap_EQ : CommaJoined<["-"], "fno-sanitize-trap=">, Group<f_clang_Group>;
 def fsanitize_undefined_trap_on_error : Flag<["-"], "fsanitize-undefined-trap-on-error">,
-                                        Group<f_clang_Group>, Flags<[CC1Option]>;
+                                        Group<f_clang_Group>;
 def fno_sanitize_undefined_trap_on_error : Flag<["-"], "fno-sanitize-undefined-trap-on-error">,
                                            Group<f_clang_Group>;
 def fsanitize_link_cxx_runtime : Flag<["-"], "fsanitize-link-c++-runtime">,
                                  Group<f_clang_Group>;
 def funsafe_math_optimizations : Flag<["-"], "funsafe-math-optimizations">,
   Group<f_Group>;
 def fno_unsafe_math_optimizations : Flag<["-"], "fno-unsafe-math-optimizations">,
   Group<f_Group>;

include/clang/Driver/SanitizerArgs.h

 namespace clang {
 namespace driver {
 
 class ToolChain;
 
 class SanitizerArgs {
   SanitizerSet Sanitizers;
   SanitizerSet RecoverableSanitizers;
+  SanitizerSet TrapSanitizers;
 
   std::vector<std::string> BlacklistFiles;
   int CoverageFeatures;
   int MsanTrackOrigins;
   int AsanFieldPadding;
   bool AsanZeroBaseShadow;
-  bool UbsanTrapOnError;
   bool AsanSharedRuntime;
   bool LinkCXXRuntimes;
 
  public:
   /// Parses the sanitizer arguments from an argument list.
   SanitizerArgs(const ToolChain &TC, const llvm::opt::ArgList &Args);
 
   bool needsAsanRt() const { return Sanitizers.has(SanitizerKind::Address); }

include/clang/Frontend/CodeGenOptions.h

public:
 
   /// Set of files definining the rules for the symbol rewriting.
   std::vector<std::string> RewriteMapFiles;
 
   /// Set of sanitizer checks that are non-fatal (i.e. execution should be
   /// continued when possible).
   SanitizerSet SanitizeRecover;
 
+  /// Set of sanitizer checks that trap rather than diagnose.
+  SanitizerSet SanitizeTrap;
+
 public:
   // Define accessors/mutators for code generation options of enumeration type.
 #define CODEGENOPT(Name, Bits, Default)
 #define ENUM_CODEGENOPT(Name, Type, Bits, Default) \
   Type get##Name() const { return static_cast<Type>(Name); } \
   void set##Name(Type Value) { Name = static_cast<unsigned>(Value); }
 #include "clang/Frontend/CodeGenOptions.def"
 
   CodeGenOptions();
 };
 
 }  // end namespace clang
 
 #endif

include/clang/Frontend/CodeGenOptions.def

 CODEGENOPT(SanitizeCoverageIndirectCalls, 1, 0) ///< Enable sanitizer coverage
                                                 ///< for indirect calls.
 CODEGENOPT(SanitizeCoverageTraceBB, 1, 0) ///< Enable basic block tracing in
                                           ///< in sanitizer coverage.
 CODEGENOPT(SanitizeCoverageTraceCmp, 1, 0) ///< Enable cmp instruction tracing
                                            ///< in sanitizer coverage.
 CODEGENOPT(SanitizeCoverage8bitCounters, 1, 0) ///< Use 8-bit frequency counters
                                                ///< in sanitizer coverage.
-CODEGENOPT(SanitizeUndefinedTrapOnError, 1, 0) ///< Set on
-                                               /// -fsanitize-undefined-trap-on-error
 CODEGENOPT(SimplifyLibCalls  , 1, 1) ///< Set when -fbuiltin is enabled.
 CODEGENOPT(SoftFloat         , 1, 0) ///< -soft-float.
 CODEGENOPT(StrictEnums       , 1, 0) ///< Optimize based on strict enum definition.
 CODEGENOPT(TimePasses        , 1, 0) ///< Set when -ftime-report is enabled.
 CODEGENOPT(UnitAtATime       , 1, 1) ///< Unused. For mirroring GCC optimization
                                      ///< selection.
 CODEGENOPT(UnrollLoops       , 1, 0) ///< Control whether loops are unrolled.
 CODEGENOPT(RerollLoops       , 1, 0) ///< Control whether loops are rerolled.

lib/CodeGen/CGExpr.cpp

void CodeGenFunction::EmitCheck(
     ArrayRef<std::pair<llvm::Value *, SanitizerMask>> Checked,
     StringRef CheckName, ArrayRef<llvm::Constant *> StaticArgs,
     ArrayRef<llvm::Value *> DynamicArgs) {
   assert(IsSanitizerScope);
   assert(Checked.size() > 0);
 
   llvm::Value *FatalCond = nullptr;
   llvm::Value *RecoverableCond = nullptr;
+  llvm::Value *TrapCond = nullptr;
   for (int i = 0, n = Checked.size(); i < n; ++i) {
     llvm::Value *Check = Checked[i].first;
+    // -fsanitize-trap= overrides -fsanitize-recover=.
     llvm::Value *&Cond =
-        CGM.getCodeGenOpts().SanitizeRecover.has(Checked[i].second)
+        CGM.getCodeGenOpts().SanitizeTrap.has(Checked[i].second)
+            ? TrapCond
+            : CGM.getCodeGenOpts().SanitizeRecover.has(Checked[i].second)
                   ? RecoverableCond
                   : FatalCond;
     Cond = Cond ? Builder.CreateAnd(Cond, Check) : Check;
   }
 
+  if (TrapCond)
+    EmitTrapCheck(TrapCond);
+  if (!FatalCond && !RecoverableCond)
+    return;
+
   llvm::Value *JointCond;
   if (FatalCond && RecoverableCond)
     JointCond = Builder.CreateAnd(FatalCond, RecoverableCond);
   else
     JointCond = FatalCond ? FatalCond : RecoverableCond;
   assert(JointCond);
 
   CheckRecoverableKind RecoverKind = getRecoverableKind(Checked[0].second);
   assert(SanOpts.has(Checked[0].second));
 #ifndef NDEBUG
   for (int i = 1, n = Checked.size(); i < n; ++i) {
     assert(RecoverKind == getRecoverableKind(Checked[i].second) &&
            "All recoverable kinds in a single check must be same!");
     assert(SanOpts.has(Checked[i].second));
   }
 #endif
 
-  if (CGM.getCodeGenOpts().SanitizeUndefinedTrapOnError) {
-    assert(RecoverKind != CheckRecoverableKind::AlwaysRecoverable &&
-           "Runtime call required for AlwaysRecoverable kind!");
-    // Assume that -fsanitize-undefined-trap-on-error overrides
-    // -fsanitize-recover= options, as we can only print meaningful error
-    // message and recover if we have a runtime support.
-    return EmitTrapCheck(JointCond);
-  }
-
   llvm::BasicBlock *Cont = createBasicBlock("cont");
   llvm::BasicBlock *Handlers = createBasicBlock("handler." + CheckName);
   llvm::Instruction *Branch = Builder.CreateCondBr(JointCond, Cont, Handlers);
   // Give hint that we very much don't expect to execute the handler
   // Value chosen to match UR_NONTAKEN_WEIGHT, see BranchProbabilityInfo.cpp
   llvm::MDBuilder MDHelper(getLLVMContext());
   llvm::MDNode *Node = MDHelper.createBranchWeights((1U << 20) - 1, 1);
   Branch->setMetadata(llvm::LLVMContext::MD_prof, Node);

lib/Driver/SanitizerArgs.cpp

enum : SanitizerMask {
   NotAllowedWithTrap = Vptr,
   RequiresPIE = Memory | DataFlow,
   NeedsUnwindTables = Address | Thread | Memory | DataFlow,
   SupportsCoverage = Address | Memory | Leak | Undefined | Integer | DataFlow,
   RecoverableByDefault = Undefined | Integer,
   Unrecoverable = Address | Unreachable | Return,
   LegacyFsanitizeRecoverMask = Undefined | Integer,
   NeedsLTO = CFI,
+  TrappingSupported = (Undefined & ~Vptr) | UndefinedGroup |
+                      UnsignedIntegerOverflow | LocalBounds,
 };
 
 enum CoverageFeature {
   CoverageFunc = 1 << 0,
   CoverageBB = 1 << 1,
   CoverageEdge = 1 << 2,
   CoverageIndirCall = 1 << 3,
   CoverageTraceBB = 1 << 4,
if (BlacklistFile) {
     clang::SmallString<64> Path(D.ResourceDir);
     llvm::sys::path::append(Path, BlacklistFile);
     BLPath = Path.str();
     return true;
   }
   return false;
 }
 
+static SanitizerMask parseSanitizeTrapArgs(const Driver &D,
+                                           const llvm::opt::ArgList &Args) {
+  SanitizerMask TrapRemove = 0; // During the loop below, the accumulated set of
+                                // sanitizers disabled by the current sanitizer
+                                // argument or any argument after it.
+  SanitizerMask TrappingKinds = 0;
+
+  for (ArgList::const_reverse_iterator I = Args.rbegin(), E = Args.rend();
+       I != E; ++I) {
+    const auto *Arg = *I;
+    if (Arg->getOption().matches(options::OPT_fsanitize_trap_EQ)) {
+      Arg->claim();
+      SanitizerMask Add = parseArgValues(D, Arg, true);
+      Add &= ~TrapRemove;
+      if ((Add & ~TrappingSupported) != 0) {
+        SanitizerSet S;
+        S.Mask = Add & ~TrappingSupported;
+        D.Diag(diag::err_drv_unsupported_option_argument) << "-fsanitize-trap"
+                                                          << toString(S);
+      }
+      TrappingKinds |= expandSanitizerGroups(Add);
+    } else if (Arg->getOption().matches(options::OPT_fno_sanitize_trap_EQ)) {
+      Arg->claim();
+      TrapRemove |= expandSanitizerGroups(parseArgValues(D, Arg, true));
+    } else if (Arg->getOption().matches(
+                   options::OPT_fsanitize_undefined_trap_on_error)) {
+      Arg->claim();
+      TrappingKinds |= expandSanitizerGroups(UndefinedGroup & ~TrapRemove);
+    } else if (Arg->getOption().matches(
+                   options::OPT_fno_sanitize_undefined_trap_on_error)) {
+      Arg->claim();
+      TrapRemove |= Undefined | UndefinedGroup;
+    }
+  }
+
+  return TrappingKinds;
+}
+
 bool SanitizerArgs::needsUbsanRt() const {
-  return !UbsanTrapOnError && (Sanitizers.Mask & NeedsUbsanRt) &&
+  return (Sanitizers.Mask & NeedsUbsanRt & ~TrapSanitizers.Mask) &&
          !Sanitizers.has(Address) &&
          !Sanitizers.has(Memory) &&
          !Sanitizers.has(Thread);
 }
 
 bool SanitizerArgs::requiresPIE() const {
   return AsanZeroBaseShadow || (Sanitizers.Mask & RequiresPIE);
 }
 
 bool SanitizerArgs::needsUnwindTables() const {
   return Sanitizers.Mask & NeedsUnwindTables;
 }
 
 bool SanitizerArgs::needsLTO() const {
   return Sanitizers.Mask & NeedsLTO;
 }
 
 void SanitizerArgs::clear() {
   Sanitizers.clear();
   RecoverableSanitizers.clear();
+  TrapSanitizers.clear();
   BlacklistFiles.clear();
   CoverageFeatures = 0;
   MsanTrackOrigins = 0;
   AsanFieldPadding = 0;
   AsanZeroBaseShadow = false;
-  UbsanTrapOnError = false;
   AsanSharedRuntime = false;
   LinkCXXRuntimes = false;
 }
 
 SanitizerArgs::SanitizerArgs(const ToolChain &TC,
                              const llvm::opt::ArgList &Args) {
   clear();
   SanitizerMask AllRemove = 0;  // During the loop below, the accumulated set of
                                 // sanitizers disabled by the current sanitizer
                                 // argument or any argument after it.
   SanitizerMask AllAddedKinds = 0;  // Mask of all sanitizers ever enabled by
                                     // -fsanitize= flags (directly or via group
                                     // expansion), some of which may be disabled
                                     // later. Used to carefully prune
                                     // unused-argument diagnostics.
   SanitizerMask DiagnosedKinds = 0;  // All Kinds we have diagnosed up to now.
                                      // Used to deduplicate diagnostics.
   SanitizerMask Kinds = 0;
   SanitizerMask NotSupported = getToolchainUnsupportedKinds(TC);
   ToolChain::RTTIMode RTTIMode = TC.getRTTIMode();
 
   const Driver &D = TC.getDriver();
+  SanitizerMask TrappingKinds = parseSanitizeTrapArgs(D, Args);
+  if (TrappingKinds & Vptr)
+    NotSupported |= Vptr;
+
   for (ArgList::const_reverse_iterator I = Args.rbegin(), E = Args.rend();
        I != E; ++I) {
     const auto *Arg = *I;
     if (Arg->getOption().matches(options::OPT_fsanitize_EQ)) {
       Arg->claim();
       SanitizerMask Add = parseArgValues(D, Arg, true);
       AllAddedKinds |= expandSanitizerGroups(Add);
 
       // Avoid diagnosing any sanitizer which is disabled later.
       Add &= ~AllRemove;
       // At this point we have not expanded groups, so any unsupported
       // sanitizers in Add are those which have been explicitly enabled.
       // Diagnose them.
-      if (SanitizerMask KindsToDiagnose =
-              Add & NotSupported & ~DiagnosedKinds) {
+      SanitizerMask KindsToDiagnose = Add & NotSupported & ~DiagnosedKinds;
+      if (KindsToDiagnose & Vptr) {
+        D.Diag(diag::err_drv_argument_not_allowed_with)
+            << "-fsanitize=vptr"
+            << "-fsanitize-trap=undefined";
+        DiagnosedKinds |= Vptr;
+        KindsToDiagnose &= ~Vptr;
+      }
+      if (KindsToDiagnose) {
         // 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;
 
SanitizerArgs::SanitizerArgs(const ToolChain &TC,
   // We disable the vptr sanitizer if it was enabled by group expansion but RTTI
   // is disabled.
   if ((Kinds & Vptr) &&
       (RTTIMode == ToolChain::RM_DisabledImplicitly ||
        RTTIMode == ToolChain::RM_DisabledExplicitly)) {
     Kinds &= ~Vptr;
   }
 
-  // Warn about undefined sanitizer options that require runtime support.
-  UbsanTrapOnError =
-    Args.hasFlag(options::OPT_fsanitize_undefined_trap_on_error,
-                 options::OPT_fno_sanitize_undefined_trap_on_error, false);
-  if (UbsanTrapOnError && (Kinds & NotAllowedWithTrap)) {
-    D.Diag(clang::diag::err_drv_argument_not_allowed_with)
-        << lastArgumentForMask(D, Args, NotAllowedWithTrap)
-        << "-fsanitize-undefined-trap-on-error";
-    Kinds &= ~NotAllowedWithTrap;
-  }
-
   // Warn about incompatible groups of sanitizers.
   std::pair<SanitizerMask, SanitizerMask> IncompatibleGroups[] = {
       std::make_pair(Address, Thread), std::make_pair(Address, Memory),
       std::make_pair(Thread, Memory), std::make_pair(Leak, Thread),
       std::make_pair(Leak, Memory)};
   for (auto G : IncompatibleGroups) {
     SanitizerMask Group = G.first;
     if (Kinds & Group) {
SanitizerArgs::SanitizerArgs(const ToolChain &TC,
 
   // Parse -link-cxx-sanitizer flag.
   LinkCXXRuntimes =
       Args.hasArg(options::OPT_fsanitize_link_cxx_runtime) || D.CCCIsCXX();
 
   // Finally, initialize the set of available and recoverable sanitizers.
   Sanitizers.Mask |= Kinds;
   RecoverableSanitizers.Mask |= RecoverableKinds;
+  TrapSanitizers.Mask |= TrappingKinds;
 }
 
 static std::string toString(const clang::SanitizerSet &Sanitizers) {
   std::string Res;
 #define SANITIZER(NAME, ID)                                                    \
   if (Sanitizers.has(ID)) {                                                    \
     if (!Res.empty())                                                          \
       Res += ",";                                                              \
     Res += NAME;                                                               \
   }
 #include "clang/Basic/Sanitizers.def"
   return Res;
 }
 
 void SanitizerArgs::addArgs(const llvm::opt::ArgList &Args,
                             llvm::opt::ArgStringList &CmdArgs) const {
   if (Sanitizers.empty())
     return;
   CmdArgs.push_back(Args.MakeArgString("-fsanitize=" + toString(Sanitizers)));
 
   if (!RecoverableSanitizers.empty())
     CmdArgs.push_back(Args.MakeArgString("-fsanitize-recover=" +
                                          toString(RecoverableSanitizers)));
 
-  if (UbsanTrapOnError)
-    CmdArgs.push_back("-fsanitize-undefined-trap-on-error");
+  if (!TrapSanitizers.empty())
+    CmdArgs.push_back(
+        Args.MakeArgString("-fsanitize-trap=" + toString(TrapSanitizers)));
 
   for (const auto &BLPath : BlacklistFiles) {
     SmallString<64> BlacklistOpt("-fsanitize-blacklist=");
     BlacklistOpt += BLPath;
     CmdArgs.push_back(Args.MakeArgString(BlacklistOpt));
   }
 
   if (MsanTrackOrigins)
if (Sanitizers.has(Memory) || Sanitizers.has(Address))
     CmdArgs.push_back(Args.MakeArgString("-fno-assume-sane-operator-new"));
 }
 
 SanitizerMask parseArgValues(const Driver &D, const llvm::opt::Arg *A,
                              bool DiagnoseErrors) {
   assert((A->getOption().matches(options::OPT_fsanitize_EQ) ||
           A->getOption().matches(options::OPT_fno_sanitize_EQ) ||
           A->getOption().matches(options::OPT_fsanitize_recover_EQ) ||
-          A->getOption().matches(options::OPT_fno_sanitize_recover_EQ)) &&
+          A->getOption().matches(options::OPT_fno_sanitize_recover_EQ) ||
+          A->getOption().matches(options::OPT_fsanitize_trap_EQ) ||
+          A->getOption().matches(options::OPT_fno_sanitize_trap_EQ)) &&
          "Invalid argument in parseArgValues!");
   SanitizerMask Kinds = 0;
   for (int i = 0, n = A->getNumValues(); i != n; ++i) {
     const char *Value = A->getValue(i);
     SanitizerMask Kind;
     // Special case: don't accept -fsanitize=all.
     if (A->getOption().matches(options::OPT_fsanitize_EQ) &&
         0 == strcmp("all", Value))

lib/Frontend/CompilerInvocation.cpp

static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
   Opts.SanitizeCoverageIndirectCalls =
       Args.hasArg(OPT_fsanitize_coverage_indirect_calls);
   Opts.SanitizeCoverageTraceBB = Args.hasArg(OPT_fsanitize_coverage_trace_bb);
   Opts.SanitizeCoverageTraceCmp = Args.hasArg(OPT_fsanitize_coverage_trace_cmp);
   Opts.SanitizeCoverage8bitCounters =
       Args.hasArg(OPT_fsanitize_coverage_8bit_counters);
   Opts.SanitizeMemoryTrackOrigins =
       getLastArgIntValue(Args, OPT_fsanitize_memory_track_origins_EQ, 0, Diags);
-  Opts.SanitizeUndefinedTrapOnError =
-      Args.hasArg(OPT_fsanitize_undefined_trap_on_error);
   Opts.SSPBufferSize =
       getLastArgIntValue(Args, OPT_stack_protector_buffer_size, 8, Diags);
   Opts.StackRealignment = Args.hasArg(OPT_mstackrealign);
   if (Arg *A = Args.getLastArg(OPT_mstack_alignment)) {
     StringRef Val = A->getValue();
     unsigned StackAlignment = Opts.StackAlignment;
     Val.getAsInteger(10, StackAlignment);
     Opts.StackAlignment = StackAlignment;
static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
 
   Opts.RewriteMapFiles = Args.getAllArgValues(OPT_frewrite_map_file);
 
   // Parse -fsanitize-recover= arguments.
   // FIXME: Report unrecoverable sanitizers incorrectly specified here.
   parseSanitizerKinds("-fsanitize-recover=",
                       Args.getAllArgValues(OPT_fsanitize_recover_EQ), Diags,
                       Opts.SanitizeRecover);
+  parseSanitizerKinds("-fsanitize-trap=",
+                      Args.getAllArgValues(OPT_fsanitize_trap_EQ), Diags,
+                      Opts.SanitizeTrap);
 
   Opts.CudaGpuBinaryFileNames =
       Args.getAllArgValues(OPT_fcuda_include_gpubinary);
 
   return Success;
 }
 
 static void ParseDependencyOutputArgs(DependencyOutputOptions &Opts,

test/CodeGen/bounds-checking.c

 // RUN: %clang_cc1 -fsanitize=local-bounds -emit-llvm -triple x86_64-apple-darwin10 %s -o - | FileCheck %s
-// RUN: %clang_cc1 -fsanitize=array-bounds -O -fsanitize-undefined-trap-on-error -emit-llvm -triple x86_64-apple-darwin10 -DNO_DYNAMIC %s -o - | FileCheck %s
+// RUN: %clang_cc1 -fsanitize=array-bounds -O -fsanitize-trap=array-bounds -emit-llvm -triple x86_64-apple-darwin10 -DNO_DYNAMIC %s -o - | FileCheck %s
 
 // CHECK-LABEL: @f
 double f(int b, int i) {
   double a[b];
   // CHECK: call {{.*}} @llvm.trap
   return a[i];
 }
 

test/CodeGen/catch-undef-behavior.c

 // RUN: %clang_cc1 -fsanitize=alignment,null,object-size,shift-base,shift-exponent,return,signed-integer-overflow,vla-bound,float-cast-overflow,integer-divide-by-zero,bool,returns-nonnull-attribute,nonnull-attribute -fsanitize-recover=alignment,null,object-size,shift-base,shift-exponent,signed-integer-overflow,vla-bound,float-cast-overflow,integer-divide-by-zero,bool,returns-nonnull-attribute,nonnull-attribute -emit-llvm %s -o - -triple x86_64-linux-gnu | FileCheck %s --check-prefix=CHECK-COMMON --check-prefix=CHECK-UBSAN
-// RUN: %clang_cc1 -fsanitize-undefined-trap-on-error -fsanitize=alignment,null,object-size,shift-base,shift-exponent,return,signed-integer-overflow,vla-bound,float-cast-overflow,integer-divide-by-zero,bool,returns-nonnull-attribute,nonnull-attribute -fsanitize-recover=alignment,null,object-size,shift-base,shift-exponent,signed-integer-overflow,vla-bound,float-cast-overflow,integer-divide-by-zero,bool,returns-nonnull-attribute,nonnull-attribute -emit-llvm %s -o - -triple x86_64-linux-gnu | FileCheck %s --check-prefix=CHECK-COMMON --check-prefix=CHECK-TRAP
+// RUN: %clang_cc1 -fsanitize-trap=alignment,null,object-size,shift-base,shift-exponent,return,signed-integer-overflow,vla-bound,float-cast-overflow,integer-divide-by-zero,bool,returns-nonnull-attribute,nonnull-attribute -fsanitize-recover=alignment,null,object-size,shift-base,shift-exponent,signed-integer-overflow,vla-bound,float-cast-overflow,integer-divide-by-zero,bool,returns-nonnull-attribute,nonnull-attribute -fsanitize=alignment,null,object-size,shift-base,shift-exponent,return,signed-integer-overflow,vla-bound,float-cast-overflow,integer-divide-by-zero,bool,returns-nonnull-attribute,nonnull-attribute -fsanitize-recover=alignment,null,object-size,shift-base,shift-exponent,signed-integer-overflow,vla-bound,float-cast-overflow,integer-divide-by-zero,bool,returns-nonnull-attribute,nonnull-attribute -emit-llvm %s -o - -triple x86_64-linux-gnu | FileCheck %s --check-prefix=CHECK-COMMON --check-prefix=CHECK-TRAP
 // RUN: %clang_cc1 -fsanitize=null -fsanitize-recover=null -emit-llvm %s -o - -triple x86_64-linux-gnu | FileCheck %s --check-prefix=CHECK-NULL
 // RUN: %clang_cc1 -fsanitize=signed-integer-overflow -emit-llvm %s -o - -triple x86_64-linux-gnu | FileCheck %s --check-prefix=CHECK-OVERFLOW
 // REQUIRES: asserts
 
 // CHECK-UBSAN: @[[INT:.*]] = private unnamed_addr constant { i16, i16, [6 x i8] } { i16 0, i16 11, [6 x i8] c"'int'\00" }
 
 // FIXME: When we only emit each type once, use [[INT]] more below.
 // CHECK-UBSAN: @[[LINE_100:.*]] = private unnamed_addr global {{.*}}, i32 100, i32 5 {{.*}} @[[INT]], i64 4, i8 1

test/CodeGen/sanitize-trap.c

+// RUN: %clang_cc1 -emit-llvm -o - %s -fsanitize=signed-integer-overflow,integer-divide-by-zero -fsanitize-trap=integer-divide-by-zero | FileCheck %s
+
+int f(int x, int y) {
+  // CHECK: %[[B1:.*]] = icmp ne i32 %[[D:.*]], 0
+  // CHECK: %[[B2:.*]] = icmp ne i32 %[[N:.*]], -2147483648
+  // CHECK: %[[B3:.*]] = icmp ne i32 %[[D]], -1
+  // CHECK: %[[B4:.*]] = or i1 %[[B2]], %[[B3]]
+  // CHECK: br i1 %[[B1]], label %[[L1:[0-9a-z_.]*]], label %[[L2:[0-9a-z_.]*]]
+
+  // CHECK: [[L2]]
+  // CHECK-NEXT: call void @llvm.trap()
+  // CHECK-NEXT: unreachable
+
+  // CHECK: [[L1]]
+  // CHECK-NEXT: br i1 %[[B4]], label %[[L3:[0-9a-z_.]*]], label %[[L4:[0-9a-z_.]*]]
+
+  // CHECK: [[L4]]
+  // CHECK-NEXT: zext
+  // CHECK-NEXT: zext
+  // CHECK-NEXT: __ubsan_handle_divrem_overflow
+
+  // CHECK: [[L3]]
+  // CHECK-NEXT: sdiv i32 %[[N]], %[[D]]
+  return x / y;
+}

test/Driver/fsanitize.c

+// RUN: %clang -target x86_64-linux-gnu -fsanitize=undefined -fsanitize-trap=undefined %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UNDEFINED-TRAP
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=undefined -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 -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
-// 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"
+// 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|function),?){18}"}}
+// CHECK-UNDEFINED-TRAP: "-fsanitize-trap={{((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|function),?){18}.}}
 
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=undefined %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UNDEFINED
 // CHECK-UNDEFINED: "-fsanitize={{((signed-integer-overflow|integer-divide-by-zero|float-divide-by-zero|function|shift-base|shift-exponent|unreachable|return|vla-bound|alignment|null|vptr|object-size|float-cast-overflow|array-bounds|enum|bool|returns-nonnull-attribute|nonnull-attribute),?){19}"}}
 
 // RUN: %clang -target x86_64-apple-darwin10 -fsanitize=undefined %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UNDEFINED-DARWIN
 // CHECK-UNDEFINED-DARWIN: "-fsanitize={{((signed-integer-overflow|integer-divide-by-zero|float-divide-by-zero|shift-base|shift-exponent|unreachable|return|vla-bound|alignment|null|vptr|object-size|float-cast-overflow|array-bounds|enum|bool|returns-nonnull-attribute|nonnull-attribute),?){18}"}}
 
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=integer %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-INTEGER

 // CHECK-FNO-SANITIZE-ALL: "-fsanitize=thread"
 
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=thread,undefined -fno-sanitize=thread -fno-sanitize=float-cast-overflow,vptr,bool,enum %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-PARTIAL-UNDEFINED
 // CHECK-PARTIAL-UNDEFINED: "-fsanitize={{((signed-integer-overflow|integer-divide-by-zero|float-divide-by-zero|function|shift-base|shift-exponent|unreachable|return|vla-bound|alignment|null|object-size|array-bounds|returns-nonnull-attribute|nonnull-attribute),?){15}"}}
 
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=shift -fno-sanitize=shift-base %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-FSANITIZE-SHIFT-PARTIAL
 // CHECK-FSANITIZE-SHIFT-PARTIAL: "-fsanitize=shift-exponent"
 
-// RUN: %clang -target x86_64-linux-gnu -fsanitize=undefined -fsanitize-undefined-trap-on-error %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UNDEFINED-TRAP-ON-ERROR-UNDEF
-// CHECK-UNDEFINED-TRAP-ON-ERROR-UNDEF: '-fsanitize=undefined' not allowed with '-fsanitize-undefined-trap-on-error'
-
-// RUN: %clang -target x86_64-linux-gnu -fsanitize=vptr -fsanitize-undefined-trap-on-error %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UNDEFINED-TRAP-ON-ERROR-VPTR
-// CHECK-UNDEFINED-TRAP-ON-ERROR-VPTR: '-fsanitize=vptr' not allowed with '-fsanitize-undefined-trap-on-error'
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=vptr -fsanitize-trap=undefined %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-VPTR-TRAP-UNDEF
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=vptr -fsanitize-undefined-trap-on-error %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-VPTR-TRAP-UNDEF
+// CHECK-VPTR-TRAP-UNDEF: error: invalid argument '-fsanitize=vptr' not allowed with '-fsanitize-trap=undefined'
 
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=vptr -fno-rtti %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-VPTR-NO-RTTI
 // CHECK-VPTR-NO-RTTI: '-fsanitize=vptr' not allowed with '-fno-rtti'
 
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=undefined -fno-rtti %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UNDEFINED-NO-RTTI
 // CHECK-UNDEFINED-NO-RTTI-NOT: vptr
 
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=address,thread -fno-rtti %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-SANA-SANT

 // RUN: %clang -target x86_64-linux-gnu -fsanitize=cfi-nvcall -c %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-CFI-NVCALL
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=cfi-vcall -c %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-CFI-VCALL
 // CHECK-CFI: -emit-llvm-bc{{.*}}-fsanitize=cfi-derived-cast,cfi-unrelated-cast,cfi-nvcall,cfi-vcall
 // CHECK-CFI-DCAST: -emit-llvm-bc{{.*}}-fsanitize=cfi-derived-cast
 // CHECK-CFI-UCAST: -emit-llvm-bc{{.*}}-fsanitize=cfi-unrelated-cast
 // CHECK-CFI-NVCALL: -emit-llvm-bc{{.*}}-fsanitize=cfi-nvcall
 // CHECK-CFI-VCALL: -emit-llvm-bc{{.*}}-fsanitize=cfi-vcall
 
+// RUN: %clang -target x86_64-linux-gnu -fsanitize-trap=address -c %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-ASAN-TRAP
+// CHECK-ASAN-TRAP: error: unsupported argument 'address' to option '-fsanitize-trap'
+
 // RUN: %clang_cl -fsanitize=address -c -MDd -### -- %s 2>&1 | FileCheck %s -check-prefix=CHECK-ASAN-DEBUGRTL
 // RUN: %clang_cl -fsanitize=address -c -MTd -### -- %s 2>&1 | FileCheck %s -check-prefix=CHECK-ASAN-DEBUGRTL
 // RUN: %clang_cl -fsanitize=address -c -LDd -### -- %s 2>&1 | FileCheck %s -check-prefix=CHECK-ASAN-DEBUGRTL
 // RUN: %clang_cl -fsanitize=address -c -MD -MDd -### -- %s 2>&1 | FileCheck %s -check-prefix=CHECK-ASAN-DEBUGRTL
 // RUN: %clang_cl -fsanitize=address -c -MT -MTd -### -- %s 2>&1 | FileCheck %s -check-prefix=CHECK-ASAN-DEBUGRTL
 // RUN: %clang_cl -fsanitize=address -c -LD -LDd -### -- %s 2>&1 | FileCheck %s -check-prefix=CHECK-ASAN-DEBUGRTL
 // CHECK-ASAN-DEBUGRTL: error: invalid argument
 // CHECK-ASAN-DEBUGRTL: not allowed with '-fsanitize=address'