[TSAN/AArch64/Android] Teach clang to link on TSAN/AArch64/Android On Android/Aarch64, there a few differences from linux/x86_64 with respect to TSAN.

[jasonk]

Summary

This should be pushed in AFTER http://reviews.llvm.org/D11532

[dvyukov]

lib/Driver/Tools.cpp

2492

If you are adding -pie to linker, I would expect that you also add -fPIE to compiler somewhere. But I can't find that other place. What am I missing?

[jasonk]

lib/Driver/Tools.cpp

2492

Good point.

[danalbert]

lib/Driver/Tools.cpp

2487

This comment might be a bit confusing to people that aren't familiar with bionic. Should probably say that the libpthread and librt functionality is bundled with libc.

2492

Not all Android devices even support PIE. This is the build system's job, not the compiler's.

2516

Why?

[jasonk]

rebase to r245497
got rid of -pie

Updating D12041: [TSAN/AArch64/Android] Teach clang to link on TSAN/AArch64/Android

On Android/Aarch64, there a few differences from linux/x86_64 with respect to
TSAN.

[jasonk]

lib/Driver/Tools.cpp

2516

TSAN requires all libs other than tsan itself to be dynamic.
TSAN itself is statically linked.
Since TSAN is (or will be) supported on aarch64-android, this return no longer makes sense.

[danalbert]

lib/Driver/Tools.cpp

2516

Explanations belong in the comment, not in the review.

[rengolin]

lib/Driver/Tools.cpp

2482

nitpick: this temp is a bit redundant...

2487

agreed.

2516

Please, split this into two returns, with a nice comment on the (android && ! AArch64).

lib/Driver/Tools.cpp

if (llvm::sys::fs::exists(SanRT + ".syms")) {
     CmdArgs.push_back(Args.MakeArgString("--dynamic-list=" + SanRT + ".syms"));
     return true;
   }
   return false;
 }
 
 static void linkSanitizerRuntimeDeps(const ToolChain &TC,
                                      ArgStringList &CmdArgs) {
+  bool isAndroid = TC.getTriple().getEnvironment() == llvm::Triple::Android;
   // Force linking against the system libraries sanitizers depends on
   // (see PR15823 why this is necessary).
   CmdArgs.push_back("--no-as-needed");
+  if (!isAndroid) {
+    // android does not need explicit links against pthread nor
+    // librt. (i.e. they don't exist!)
     CmdArgs.push_back("-lpthread");
     CmdArgs.push_back("-lrt");
     CmdArgs.push_back("-lutil");
+  }
+
   CmdArgs.push_back("-lm");
   // There's no libdl on FreeBSD.
   if (TC.getTriple().getOS() != llvm::Triple::FreeBSD)
     CmdArgs.push_back("-ldl");
 }
 
 static void
 collectSanitizerRuntimes(const ToolChain &TC, const ArgList &Args,
                          SmallVectorImpl<StringRef> &SharedRuntimes,
                          SmallVectorImpl<StringRef> &StaticRuntimes,
                          SmallVectorImpl<StringRef> &HelperStaticRuntimes) {
   const SanitizerArgs &SanArgs = TC.getSanitizerArgs();
   // Collect shared runtimes.
   if (SanArgs.needsAsanRt() && SanArgs.needsSharedAsanRt()) {
     SharedRuntimes.push_back("asan");
   }
 
   // Collect static runtimes.
   if (Args.hasArg(options::OPT_shared) ||
-      (TC.getTriple().getEnvironment() == llvm::Triple::Android)) {
+      (TC.getTriple().getEnvironment() == llvm::Triple::Android &&
+       TC.getTriple().getArch() != llvm::Triple::aarch64)) {
     // Don't link static runtimes into DSOs or if compiling for Android.
+    // put in an exception for aarch64
     return;
   }
   if (SanArgs.needsAsanRt()) {
     if (SanArgs.needsSharedAsanRt()) {
       HelperStaticRuntimes.push_back("asan-preinit");
     } else {
       StaticRuntimes.push_back("asan");
       if (SanArgs.linkCXXRuntimes())