[UBSan] Use shared library for UBSan on OS X (Clang part).

[samsonov]

Summary

UBSan is now used in the same way as ASan, and is supported on
OSX and on iOS simulator. At the moment ASan and UBSan can't be used
together due to PR21112, but I hope to resolve it soon by
embedding UBSan into ASan.

[samsonov]

• Update to still allow ASan+UBSan combination.

lib/Driver/ToolChains.cpp

if (Args.hasFlag(options::OPT_fprofile_arcs, options::OPT_fno_profile_arcs,
     if (isTargetIOSBased())
       AddLinkRuntimeLib(Args, CmdArgs, "libclang_rt.profile_ios.a");
     else
       AddLinkRuntimeLib(Args, CmdArgs, "libclang_rt.profile_osx.a");
   }
 
   const SanitizerArgs &Sanitize = getSanitizerArgs();
 
-  // Add Ubsan runtime library, if required.
-  if (Sanitize.needsUbsanRt()) {
-    // FIXME: Move this check to SanitizerArgs::filterUnsupportedKinds.
-    if (isTargetIOSBased()) {
-      getDriver().Diag(diag::err_drv_clang_unsupported_per_platform)
+  // Add ASan/UBSan runtime libraries, if required.
+  if (Sanitize.needsAsanRt() || Sanitize.needsUbsanRt()) {
+    // For now we can't use ASan and UBSan together on Mac (PR21112).
+    if (Sanitize.needsAsanRt() && Sanitize.needsUbsanRt()) {
+      getDriver().Diag(diag::err_drv_argument_not_allowed_with)
+          << "-fsanitize=address"
           << "-fsanitize=undefined";
-    } else {
-      assert(isTargetMacOS() && "unexpected non OS X target");
-      AddLinkRuntimeLib(Args, CmdArgs, "libclang_rt.ubsan_osx.a", true);
-
-      // The Ubsan runtime library requires C++.
-      AddCXXStdlibLibArgs(Args, CmdArgs);
-    }
-  }
-
-  // Add ASAN runtime library, if required. Dynamic libraries and bundles
-  // should not be linked with the runtime library.
-  if (Sanitize.needsAsanRt()) {
+    } else if (!isTargetMacOS() && !isTargetIOSSimulator()) {
       // FIXME: Move this check to SanitizerArgs::filterUnsupportedKinds.
-    if (isTargetIPhoneOS()) {
-      getDriver().Diag(diag::err_drv_clang_unsupported_per_platform)
-        << "-fsanitize=address";
+      StringRef Arg = Sanitize.needsAsanRt() ? "-fsanitize=address"
+                                             : "-fsanitize=undefined";
+      getDriver().Diag(diag::err_drv_clang_unsupported_per_platform) << Arg;
     } else {
       if (!Args.hasArg(options::OPT_dynamiclib) &&
           !Args.hasArg(options::OPT_bundle)) {
-        // The ASAN runtime library requires C++.
+        // Sanitizer runtime libraries requires C++.
         AddCXXStdlibLibArgs(Args, CmdArgs);
+        // Add explicit dependcy on -lc++abi, as -lc++ doesn't re-export
+        // all RTTI-related symbols that UBSan uses.
+        if (Sanitize.needsUbsanRt())
+          CmdArgs.push_back("-lc++abi");
       }
-      if (isTargetMacOS()) {
-        AddLinkRuntimeLib(Args, CmdArgs,
-                          "libclang_rt.asan_osx_dynamic.dylib",
-                          /*AlwaysLink*/ true, /*IsEmbedded*/ false,
-                          /*AddRPath*/ true);
-      } else {
-        if (isTargetIOSSimulator()) {
-          AddLinkRuntimeLib(Args, CmdArgs,
-                            "libclang_rt.asan_iossim_dynamic.dylib",
-                            /*AlwaysLink*/ true, /*IsEmbedded*/ false,
-                            /*AddRPath*/ true);
-        }
-      }
-    }
-  }
+      StringRef OS = isTargetMacOS() ? "osx" : "iossim";
+      StringRef Sanitizer = Sanitize.needsAsanRt() ? "asan" : "ubsan";
+      AddLinkRuntimeLib(Args, CmdArgs, (Twine("libclang_rt.") + Sanitizer +
+                                        "_" + OS + "_dynamic.dylib").str(),
 
   // Otherwise link libSystem, then the dynamic runtime library, and finally any
   // target specific static runtime library.
   CmdArgs.push_back("-lSystem");
 
   // Select the dynamic runtime library and the target specific static library.
   if (isTargetIOSBased()) {
     // If we are compiling as iOS / simulator, don't attempt to link libgcc_s.1,

runtime/compiler-rt/Makefile

 # support.
 RuntimeDirs :=
 ifeq ($(OS),Darwin)
 RuntimeDirs += darwin macho_embedded
 RuntimeLibrary.darwin.Configs := \
   eprintf.a 10.4.a osx.a cc_kext.a \
   asan_osx_dynamic.dylib \
   profile_osx.a \
-  ubsan_osx.a
+  ubsan_osx_dynamic.dylib
 
 IOS_SDK := $(shell xcrun --show-sdk-path -sdk iphoneos 2> /dev/null)
 IOSSIM_SDK := $(shell xcrun --show-sdk-path -sdk iphonesimulator 2> /dev/null)
 
 ifneq ($(IOS_SDK)$(IOSSIM_SDK),)
 RuntimeLibrary.darwin.Configs += ios.a profile_ios.a
 endif
 
 ifneq ($(IOS_SDK),)
 RuntimeLibrary.darwin.Configs += cc_kext_ios5.a
 endif
 
 ifneq ($(IOSSIM_SDK),)
-RuntimeLibrary.darwin.Configs += asan_iossim_dynamic.dylib
+RuntimeLibrary.darwin.Configs += asan_iossim_dynamic.dylib \
+                                 ubsan_iossim_dynamic.dylib
 endif
 
 RuntimeLibrary.macho_embedded.Configs := \
   hard_static.a hard_pic.a
 ifneq (,$(findstring ARM,$(TARGETS_TO_BUILD)))
 RuntimeLibrary.macho_embedded.Configs += \
   soft_static.a soft_pic.a
 endif

test/Driver/darwin-sanitizer-ld.c

 // CHECK-DYN-ASAN: "-rpath" "@executable_path"
 // CHECK-DYN-ASAN: "-rpath" "{{.*}}lib{{.*}}darwin"
 
 // RUN: %clang -no-canonical-prefixes -### -target x86_64-darwin \
 // RUN:   -fsanitize=undefined %s -o %t.o 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-UBSAN %s
 
 // CHECK-UBSAN: "{{.*}}ld{{(.exe)?}}"
-// CHECK-UBSAN: libclang_rt.ubsan_osx.a"
 // CHECK-UBSAN: stdc++
+// CHECK-UBSAN: libclang_rt.ubsan_osx_dynamic.dylib"
+// CHECK-UBSAN: "-rpath" "@executable_path"
+// CHECK-UBSAN: "-rpath" "{{.*}}lib{{.*}}darwin"
 
 // RUN: %clang -no-canonical-prefixes -### -target x86_64-darwin \
 // RUN:   -fsanitize=bounds -fsanitize-undefined-trap-on-error \
 // RUN:   %s -o %t.o 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-BOUNDS %s
 
 // CHECK-BOUNDS: "{{.*}}ld{{(.exe)?}}"
 // CHECK-BOUNDS-NOT: libclang_rt.ubsan_osx.a"
 
 // RUN: %clang -no-canonical-prefixes -### -target x86_64-darwin \
 // RUN:   -fPIC -shared -fsanitize=undefined %s -o %t.so 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-DYN-UBSAN %s
 
 // CHECK-DYN-UBSAN: "{{.*}}ld{{(.exe)?}}"
 // CHECK-DYN-UBSAN: "-dylib"
-// CHECK-DYN-UBSAN: libclang_rt.ubsan_osx.a
+// CHECK-DYN-UBSAN: libclang_rt.ubsan_osx_dynamic.dylib"
+// CHECK-DYN-UBSAN: "-rpath" "@executable_path"
+// CHECK-DYN-UBSAN: "-rpath" "{{.*}}lib{{.*}}darwin"
 
 // RUN: %clang -no-canonical-prefixes -### -target x86_64-darwin \
 // RUN:   -fsanitize=bounds -fsanitize-undefined-trap-on-error \
 // RUN:   %s -o %t.so -fPIC -shared 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-DYN-BOUNDS %s
 
 // CHECK-DYN-BOUNDS: "{{.*}}ld{{(.exe)?}}"
-// CHECK-DYN-BOUNDS-NOT: libclang_rt.ubsan_osx.a
+// CHECK-DYN-BOUNDS-NOT: ubsan_osx
+
+// RUN: %clang -no-canonical-prefixes -### -target x86_64-darwin \
+// RUN:   -fsanitize=address,undefined %s -o %t.o 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-ASAN-UBSAN %s
+
+// CHECK-ASAN-UBSAN: error: invalid argument '-fsanitize=address' not allowed with '-fsanitize=undefined'