[MIPS] Add support for direct-to-nacl in Clang

lib/Driver/Tools.cpp

 //===--- Tools.cpp - Tools Implementations --------------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 
 #include "Tools.h"
@@ skipping 1211 matching lines @@
       CmdArgs.push_back("-mno-check-zero-division");
     }
   }
 
   if (Arg *A = Args.getLastArg(options::OPT_G)) {
     StringRef v = A->getValue();
     CmdArgs.push_back("-mllvm");
     CmdArgs.push_back(Args.MakeArgString("-mips-ssection-threshold=" + v));
     A->claim();
   }
+
+  // @LOCALMOD-BEGIN
+  if (Triple.getOS() == llvm::Triple::NaCl) {
+    CmdArgs.push_back("-mllvm");
+    CmdArgs.push_back("-direct-to-nacl");
+  }
+  // @LOCALMOD-END
 }
 
 /// getPPCTargetCPU - Get the (LLVM) name of the PowerPC cpu we are targeting.
 static std::string getPPCTargetCPU(const ArgList &Args) {
   if (Arg *A = Args.getLastArg(options::OPT_mcpu_EQ)) {
     StringRef CPUName = A->getValue();
 
     if (CPUName == "native") {
       std::string CPU = llvm::sys::getHostCPUName();
       if (!CPU.empty() && CPU != "generic")
@@ skipping 6809 matching lines @@
   if (!IsStatic)
     CmdArgs.push_back("--eh-frame-hdr");
 
   CmdArgs.push_back("-m");
   if (ToolChain.getArch() == llvm::Triple::x86)
     CmdArgs.push_back("elf_i386_nacl");
   else if (ToolChain.getArch() == llvm::Triple::arm)
     CmdArgs.push_back("armelf_nacl");
   else if (ToolChain.getArch() == llvm::Triple::x86_64)
     CmdArgs.push_back("elf_x86_64_nacl");
+  else if (ToolChain.getArch() == llvm::Triple::mipsel)
+    CmdArgs.push_back("mipselelf_nacl");
   else
     D.Diag(diag::err_target_unsupported_arch) << ToolChain.getArchName() <<
         "Native Client";
 
 
   if (IsStatic)
     CmdArgs.push_back("-static");
   else if (Args.hasArg(options::OPT_shared))
     CmdArgs.push_back("-shared");
 
@@ skipping 44 matching lines @@
   if (!Args.hasArg(options::OPT_nostdlib)) {
     if (!Args.hasArg(options::OPT_nodefaultlibs)) {
       // Always use groups, since it has no effect on dynamic libraries.
       CmdArgs.push_back("--start-group");
       CmdArgs.push_back("-lc");
       // NaCl's libc++ currently requires libpthread, so just always include it
       // in the group for C++.
       if (Args.hasArg(options::OPT_pthread) ||
           Args.hasArg(options::OPT_pthreads) ||
           D.CCCIsCXX()) {
+        // Gold, used by Mips, handles nested groups differently than ld, and
+        // without '-lnacl' it prefers symbols from libpthread.a over libnacl.a,
+        // which is not a desired behaviour here.
+        // See https://sourceware.org/ml/binutils/2015-03/msg00034.html
+        if (getToolChain().getArch() == llvm::Triple::mipsel)
+          CmdArgs.push_back("-lnacl");
+
         CmdArgs.push_back("-lpthread");
       }
 
       CmdArgs.push_back("-lgcc");
       CmdArgs.push_back("--as-needed");
       if (IsStatic)
         CmdArgs.push_back("-lgcc_eh");
       else
         CmdArgs.push_back("-lgcc_s");
       CmdArgs.push_back("--no-as-needed");
+
+      // Mips needs to create and use pnacl_legacy library that contains
+      // definitions from bitcode/pnaclmm.c and definitions for
+      // __nacl_tp_tls_offset() and __nacl_tp_tdb_offset().
+      if (getToolChain().getArch() == llvm::Triple::mipsel)
+        CmdArgs.push_back("-lpnacl_legacy");
+
       CmdArgs.push_back("--end-group");
     }
 
     if (!Args.hasArg(options::OPT_nostartfiles)) {
       const char *crtend;
       if (Args.hasArg(options::OPT_shared))
         crtend = "crtendS.o";
       else
         crtend = "crtend.o";
 
@@ skipping 751 matching lines @@
       CmdArgs.push_back("-lmsvcrt");
       AddRunTimeLibs(TC, D, CmdArgs, Args);
     }
   }
 
   const std::string Linker = TC.GetProgramPath("ld");
   Exec = Args.MakeArgString(Linker);
 
   C.addCommand(llvm::make_unique<Command>(JA, *this, Exec, CmdArgs));
 }