[Driver] Link shared asan runtime lib with -z now on Solaris/x86

[ro]

Summary

As detailed in Issue #64126, several asan tests FAIL due to a cycle in AsanInitInternal. This can by avoided by disabling lazy binding with ld -z now.

Tested on amd64-pc-solaris2.11.

[MaskRay]

This needs a clang/test/Driver test.

[ro]

In D156325#4537237, @MaskRay wrote:

This needs a clang/test/Driver test.

Indeed, I forgot. Added now.

[ro]

Add testcases.

Re-tested on amd64-pc-solaris2.11 and x86_64-pc-linux-gnu.

clang/lib/Driver/ToolChains/Solaris.cpp

if (getToolChain().getTriple().getArch() == llvm::Triple::sparc) {
       CmdArgs.push_back(getAsNeededOption(getToolChain(), false));
     }
     CmdArgs.push_back("-lgcc_s");
     CmdArgs.push_back("-lc");
     if (!Args.hasArg(options::OPT_shared)) {
       CmdArgs.push_back("-lgcc");
       CmdArgs.push_back("-lm");
     }
+    const SanitizerArgs &SA = getToolChain().getSanitizerArgs(Args);
     if (NeedsSanitizerDeps) {
       linkSanitizerRuntimeDeps(getToolChain(), CmdArgs);
 
       // Work around Solaris/amd64 ld bug when calling __tls_get_addr directly.
       // However, ld -z relax=transtls is available since Solaris 11.2, but not
       // in Illumos.
-      const SanitizerArgs &SA = getToolChain().getSanitizerArgs(Args);
       if (getToolChain().getTriple().getArch() == llvm::Triple::x86_64 &&
           (SA.needsAsanRt() || SA.needsStatsRt() ||
            (SA.needsUbsanRt() && !SA.requiresMinimalRuntime())))
         CmdArgs.push_back("-zrelax=transtls");
     }
+    // Avoid AsanInitInternal cycle, Issue #64126.
+    if (getToolChain().getTriple().isX86() && SA.needsSharedRt() &&
+        SA.needsAsanRt())
+      CmdArgs.push_back("-znow");
   }
 
   if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles,
                    options::OPT_r)) {
     CmdArgs.push_back(
         Args.MakeArgString(getToolChain().GetFilePath("crtend.o")));
     CmdArgs.push_back(
         Args.MakeArgString(getToolChain().GetFilePath("crtn.o")));