[Driver] Sanitizer support based on runtime library presence

The runtime libraries of sanitizers are built in compiler-rt, and Clang
can be built without compiler-rt, or compiler-rt can be configured to
only build certain sanitizers. The driver should provide reasonable
diagnostics and not a link-time error when a runtime library is missing.

This patch changes the driver for OS X to only support sanitizers of
which we can find the runtime libraries. The discussion for this patch
explains the rationale

Differential Revision: https://reviews.llvm.org/D15225

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@337635 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 51 insertions, 22 deletions

diff --git a/lib/Driver/ToolChains/Darwin.cpp b/lib/Driver/ToolChains/Darwin.cpp
index 9205dd52de..95ec8d64c2 100644
--- a/lib/Driver/ToolChains/Darwin.cpp
+++ b/lib/Driver/ToolChains/Darwin.cpp
@@ -916,13 +916,26 @@ unsigned DarwinClang::GetDefaultDwarfVersion() const {
   return 4;
 }
 
+SmallString<128> MachO::runtimeLibDir(bool IsEmbedded) const {
+  SmallString<128> Dir(getDriver().ResourceDir);
+  llvm::sys::path::append(
+      Dir, "lib", IsEmbedded ? "macho_embedded" : "darwin");
+  return Dir;
+}
+
+std::string Darwin::getFileNameForSanitizerLib(StringRef SanitizerName,
+                                              bool Shared) const {
+  return (Twine("libclang_rt.") + SanitizerName + "_" +
+                      getOSLibraryNameSuffix() +
+                      (Shared ? "_dynamic.dylib" : ".a")).str();
+
+}
+
 void MachO::AddLinkRuntimeLib(const ArgList &Args, ArgStringList &CmdArgs,
                               StringRef DarwinLibName,
                               RuntimeLinkOptions Opts) const {
-  SmallString<128> Dir(getDriver().ResourceDir);
-  llvm::sys::path::append(
-      Dir, "lib", (Opts & RLO_IsEmbedded) ? "macho_embedded" : "darwin");
 
+  SmallString<128> Dir = runtimeLibDir(Opts & RLO_IsEmbedded);
   SmallString<128> P(Dir);
   llvm::sys::path::append(P, DarwinLibName);
 
@@ -1042,12 +1055,9 @@ void DarwinClang::AddLinkSanitizerLibArgs(const ArgList &Args,
                                           StringRef Sanitizer,
                                           bool Shared) const {
   auto RLO = RuntimeLinkOptions(RLO_AlwaysLink | (Shared ? RLO_AddRPath : 0U));
-  AddLinkRuntimeLib(Args, CmdArgs,
-                    (Twine("libclang_rt.") + Sanitizer + "_" +
-                     getOSLibraryNameSuffix() +
-                     (Shared ? "_dynamic.dylib" : ".a"))
-                        .str(),
-                    RLO);
+  std::string SanitizerRelFilename =
+      getFileNameForSanitizerLib(Sanitizer, Shared);
+  AddLinkRuntimeLib(Args, CmdArgs, SanitizerRelFilename, RLO);
 }
 
 ToolChain::RuntimeLibType DarwinClang::GetRuntimeLibType(
@@ -2285,24 +2295,43 @@ void Darwin::CheckObjCARC() const {
 SanitizerMask Darwin::getSupportedSanitizers() const {
   const bool IsX86_64 = getTriple().getArch() == llvm::Triple::x86_64;
   SanitizerMask Res = ToolChain::getSupportedSanitizers();
-  Res |= SanitizerKind::Address;
-  Res |= SanitizerKind::Leak;
-  Res |= SanitizerKind::Fuzzer;
-  Res |= SanitizerKind::FuzzerNoLink;
+
+  {
+    using namespace SanitizerKind;
+    assert(!(Res & (Address | Leak | Fuzzer | FuzzerNoLink | Thread)) &&
+           "Sanitizer is already registered as supported");
+  }
+
+  if (sanitizerRuntimeExists("asan"))
+    Res |= SanitizerKind::Address;
+  if (sanitizerRuntimeExists("lsan"))
+    Res |= SanitizerKind::Leak;
+  if (sanitizerRuntimeExists("fuzzer", /*Shared=*/false)) {
+    Res |= SanitizerKind::Fuzzer;
+    Res |= SanitizerKind::FuzzerNoLink;
+  }
   Res |= SanitizerKind::Function;
-  if (isTargetMacOS()) {
-    if (!isMacosxVersionLT(10, 9))
-      Res |= SanitizerKind::Vptr;
+  if (isTargetMacOS() && !isMacosxVersionLT(10, 9))
+    Res |= SanitizerKind::Vptr;
+  if (isTargetMacOS())
     Res |= SanitizerKind::SafeStack;
-    if (IsX86_64)
-      Res |= SanitizerKind::Thread;
-  } else if (isTargetIOSSimulator() || isTargetTvOSSimulator()) {
-    if (IsX86_64)
-      Res |= SanitizerKind::Thread;
-  }
+
+  if (sanitizerRuntimeExists("tsan") && IsX86_64 &&
+      (isTargetMacOS() || isTargetIOSSimulator() || isTargetTvOSSimulator()))
+    Res |= SanitizerKind::Thread;
+
   return Res;
 }
 
 void Darwin::printVerboseInfo(raw_ostream &OS) const {
   CudaInstallation.print(OS);
 }
+
+bool Darwin::sanitizerRuntimeExists(StringRef SanitizerName,
+                                    bool Shared) const {
+    std::string RelName = getFileNameForSanitizerLib(SanitizerName, Shared);
+    SmallString<128> Dir = runtimeLibDir();
+    SmallString<128> AbsName(Dir);
+    llvm::sys::path::append(AbsName, RelName);
+    return getVFS().exists(AbsName);
+}