[sanitizer] Don't add --export-dynamic for Myriad

[waltl]

Summary

This is to work around a bug in some versions of gnu ld, where
--export-dynamic implies -shared even if -static is explicitly given.
Myriad supports static linking only, so --export-dynamic is never
needed.

[alekseyshl]

clang/lib/Driver/ToolChains/CommonArgs.cpp

711

Maybe this logic should be in addSanitizerDynamicList, similar to how it is handled for Solaris?

[waltl]

Address CR comments

clang/lib/Driver/ToolChains/CommonArgs.cpp

 // from the runtime library. Returns true if the file was found.
 static bool addSanitizerDynamicList(const ToolChain &TC, const ArgList &Args,
                                     ArgStringList &CmdArgs,
                                     StringRef Sanitizer) {
   // Solaris ld defaults to --export-dynamic behaviour but doesn't support
   // the option, so don't try to pass it.
   if (TC.getTriple().getOS() == llvm::Triple::Solaris)
     return true;
+  // Myriad is static linking only.  Furthermore, some versions of its
+  // linker have the bug where --export-dynamic overrides -static, so
+  // don't use --export-dynamic on that platform.
+  if (TC.getTriple().getVendor() == llvm::Triple::Myriad)
+    return true;
   SmallString<128> SanRT(TC.getCompilerRT(Args, Sanitizer));
   if (llvm::sys::fs::exists(SanRT + ".syms")) {
     CmdArgs.push_back(Args.MakeArgString("--dynamic-list=" + SanRT + ".syms"));
     return true;
   }
   return false;
 }
 
for (auto RT : NonWholeStaticRuntimes) {
     AddExportDynamic |= !addSanitizerDynamicList(TC, Args, CmdArgs, RT);
   }
   for (auto S : RequiredSymbols) {
     CmdArgs.push_back("-u");
     CmdArgs.push_back(Args.MakeArgString(S));
   }
   // If there is a static runtime with no dynamic list, force all the symbols
   // to be dynamic to be sure we export sanitizer interface functions.
   if (AddExportDynamic)
     CmdArgs.push_back("--export-dynamic");
 
   const SanitizerArgs &SanArgs = TC.getSanitizerArgs();
   if (SanArgs.hasCrossDsoCfi() && !AddExportDynamic)
     CmdArgs.push_back("-export-dynamic-symbol=__cfi_check");
 
   return !StaticRuntimes.empty() || !NonWholeStaticRuntimes.empty();
 }