[Sanitizers] Provide better diagnostic for sanitizers unsupported for target triple.

Summary:
Introduce ToolChain::getSupportedSanitizers() that would return the set
of sanitizers available on given toolchain. By default, these are
sanitizers which don't necessarily require runtime support (i.e.
set from -fsanitize=undefined-trap).

Sanitizers (ASan, DFSan, TSan, MSan etc.) which cannot function
without runtime library are marked as supported only on platforms
for which we actually build these runtimes.

This would allow more fine-grained checks in the future: for instance,
we have to restrict availability of -fsanitize=vptr to Mac OS 10.9+
(PR23539)

Update test cases accrodingly: add tests for certain unsupported
configurations, remove test cases for -fsanitize=vptr + PS4
integration, as we don't build the runtime for PS4 at the moment.

Test Plan: regression test suite

Reviewers: pcc

Subscribers: cfe-commits, filcab, eugenis, thakis, kubabrecka, emaste, rsmith

Differential Revision: http://reviews.llvm.org/D10467

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@239953 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/clang/Basic/Sanitizers.h b/include/clang/Basic/Sanitizers.h
index 3b1797e9f5398a33c2440b81f6f0c86064b07255..a3afcb12913dfbd899393ff45d1f01b2d44ee506 100644 (file)
--- a/include/clang/Basic/Sanitizers.h
+++ b/include/clang/Basic/Sanitizers.h
@@ -73,6 +73,9 @@ SanitizerMask parseSanitizerValue(StringRef Value, bool AllowGroups);
 /// 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

diff --git a/include/clang/Driver/ToolChain.h b/include/clang/Driver/ToolChain.h
index 4471f21f498dc2c969fdc7fc83aa7c44f234161e..d6c5cfdcb75c0e31ad6221aff3fe72761831cb1d 100644 (file)
--- a/include/clang/Driver/ToolChain.h
+++ b/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 @@ public:
   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

diff --git a/lib/Basic/Sanitizers.cpp b/lib/Basic/Sanitizers.cpp
index 8c4884b8ec367ae208a7f390b712b2431c96ca97..527d7f0c70e86da24ff83654ee5e418c0a465b7c 100644 (file)
--- a/lib/Basic/Sanitizers.cpp
+++ b/lib/Basic/Sanitizers.cpp
@@ -56,3 +56,9 @@ SanitizerMask clang::expandSanitizerGroups(SanitizerMask Kinds) {
 #include "clang/Basic/Sanitizers.def"
   return Kinds;
 }
+
+SanitizerMask clang::getSanitizersWithNoRequiredRuntime() {
+  return SanitizerKind::UndefinedTrap | SanitizerKind::CFI |
+         SanitizerKind::CFICastStrict | SanitizerKind::UnsignedIntegerOverflow |
+         SanitizerKind::LocalBounds;
+}

diff --git a/lib/Driver/MSVCToolChain.cpp b/lib/Driver/MSVCToolChain.cpp
index d824fe4c10839156b3dcacaf1c3217c02674c929..72161213db055d360f072fadaff04451d495ecb6 100644 (file)
--- a/lib/Driver/MSVCToolChain.cpp
+++ b/lib/Driver/MSVCToolChain.cpp
@@ -522,3 +522,12 @@ MSVCToolChain::ComputeEffectiveClangTriple(const ArgList &Args,
   }
   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;
+}

diff --git a/lib/Driver/SanitizerArgs.cpp b/lib/Driver/SanitizerArgs.cpp
index 72530b442f52f2ca43314d523f9c1a3130532230..8cbda7f34f00b8b0fea1d9d9434ef738380465a8 100644 (file)
--- a/lib/Driver/SanitizerArgs.cpp
+++ b/lib/Driver/SanitizerArgs.cpp
@@ -74,27 +74,6 @@ static std::string describeSanitizeArg(const llvm::opt::Arg *A,
 /// 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 @@ static bool getDefaultBlacklist(const Driver &D, SanitizerMask Kinds,
   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 @@ SanitizerArgs::SanitizerArgs(const ToolChain &TC,
   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 @@ SanitizerArgs::SanitizerArgs(const ToolChain &TC,
       // 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 @@ SanitizerArgs::SanitizerArgs(const ToolChain &TC,
       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)) {

diff --git a/lib/Driver/ToolChains.cpp b/lib/Driver/ToolChains.cpp
index e3dab2040fc6deb390a6c6ca67f55daf0be91dfb..aaaab9cecd28071d5f6aefe41a62d3b0639bbc52 100644 (file)
--- a/lib/Driver/ToolChains.cpp
+++ b/lib/Driver/ToolChains.cpp
@@ -399,26 +399,10 @@ void DarwinClang::AddLinkRuntimeLibArgs(const ArgList &Args,
 
 
   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.
@@ -1097,6 +1081,18 @@ void Darwin::CheckObjCARC() const {
   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.
@@ -2737,6 +2733,24 @@ bool FreeBSD::isPIEDefault() const {
   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)
@@ -3641,6 +3655,27 @@ bool Linux::isPIEDefault() const {
   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)

diff --git a/lib/Driver/ToolChains.h b/lib/Driver/ToolChains.h
index 0b7073f2ba0b3ad48dd1a9d5ead71752229e8622..401aa839c21cd2a0b65e8332a0be9febffe6fd23 100644 (file)
--- a/lib/Driver/ToolChains.h
+++ b/lib/Driver/ToolChains.h
@@ -474,6 +474,8 @@ public:
   void CheckObjCARC() const override;
 
   bool UseSjLjExceptions() const override;
+
+  SanitizerMask getSupportedSanitizers() const override;
 };
 
 /// DarwinClang - The Darwin toolchain used by Clang.
@@ -616,6 +618,7 @@ public:
 
   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 @@ public:
   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 @@ public:
 
   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,

diff --git a/test/Driver/asan.c b/test/Driver/asan.c
index f199e904e758dfa38e2be59d791d23c6a9a3bfb2..bea8544595d7aa41e4accce6dc436d703778f431 100644 (file)
--- a/test/Driver/asan.c
+++ b/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; }

diff --git a/test/Driver/fsanitize.c b/test/Driver/fsanitize.c
index 964ad2b1d74dfd56bd4bf5888bb49fe4217baa8e..ceaca343fa3cfc88f9d05f89e75246b30c91efa0 100644 (file)
--- a/test/Driver/fsanitize.c
+++ b/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

diff --git a/test/Driver/rtti-options.cpp b/test/Driver/rtti-options.cpp
index 46072ca6ea74edd007df91c8f057efdfd300d5d4..ba072345852ad34662ce4397d624d0935bae25ec 100644 (file)
--- a/test/Driver/rtti-options.cpp
+++ b/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'