1 files changed, 13 insertions, 32 deletions

diff --git a/lib/Driver/ToolChains/WebAssembly.cpp b/lib/Driver/ToolChains/WebAssembly.cpp
index 058bc42323e2..8ae1b6c2f55d 100644
--- a/lib/Driver/ToolChains/WebAssembly.cpp
+++ b/lib/Driver/ToolChains/WebAssembly.cpp
@@ -38,46 +38,25 @@ void wasm::Linker::ConstructJob(Compilation &C, const JobAction &JA,
                                 const char *LinkingOutput) const {
 
   const ToolChain &ToolChain = getToolChain();
-  const Driver &D = ToolChain.getDriver();
   const char *Linker = Args.MakeArgString(ToolChain.GetLinkerPath());
   ArgStringList CmdArgs;
   CmdArgs.push_back("-flavor");
   CmdArgs.push_back("wasm");
 
-  // Enable garbage collection of unused input sections by default, since code
-  // size is of particular importance. This is significantly facilitated by
-  // the enabling of -ffunction-sections and -fdata-sections in
-  // Clang::ConstructJob.
-  if (areOptimizationsEnabled(Args))
-    CmdArgs.push_back("--gc-sections");
-
-  if (Args.hasArg(options::OPT_rdynamic))
-    CmdArgs.push_back("-export-dynamic");
   if (Args.hasArg(options::OPT_s))
     CmdArgs.push_back("--strip-all");
-  if (Args.hasArg(options::OPT_shared))
-    CmdArgs.push_back("-shared");
-  if (Args.hasArg(options::OPT_static))
-    CmdArgs.push_back("-Bstatic");
 
   Args.AddAllArgs(CmdArgs, options::OPT_L);
+  Args.AddAllArgs(CmdArgs, options::OPT_u);
   ToolChain.AddFilePathLibArgs(Args, CmdArgs);
 
-  if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles)) {
-    if (Args.hasArg(options::OPT_shared))
-      CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("rcrt1.o")));
-    else if (Args.hasArg(options::OPT_pie))
-      CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("Scrt1.o")));
-    else
-      CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crt1.o")));
-
-    CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crti.o")));
-  }
+  if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles))
+    CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crt1.o")));
 
   AddLinkerInputs(ToolChain, Inputs, Args, CmdArgs, JA);
 
   if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
-    if (D.CCCIsCXX())
+    if (ToolChain.ShouldLinkCXXStdlib(Args))
       ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);
 
     if (Args.hasArg(options::OPT_pthread))
@@ -86,12 +65,9 @@ void wasm::Linker::ConstructJob(Compilation &C, const JobAction &JA,
     CmdArgs.push_back("-allow-undefined-file");
     CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("wasm.syms")));
     CmdArgs.push_back("-lc");
-    CmdArgs.push_back("-lcompiler_rt");
+    AddRunTimeLibs(ToolChain, ToolChain.getDriver(), CmdArgs, Args);
   }
 
-  if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles))
-    CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crtn.o")));
-
   CmdArgs.push_back("-o");
   CmdArgs.push_back(Output.getFilename());
 
@@ -123,9 +99,6 @@ bool WebAssembly::isPICDefaultForced() const { return false; }
 
 bool WebAssembly::IsIntegratedAssemblerDefault() const { return true; }
 
-// TODO: Support Objective C stuff.
-bool WebAssembly::SupportsObjCGC() const { return false; }
-
 bool WebAssembly::hasBlocksRuntime() const { return false; }
 
 // TODO: Support profiling.
@@ -163,6 +136,14 @@ void WebAssembly::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
                      getDriver().SysRoot + "/include/c++/v1");
 }
 
+std::string WebAssembly::getThreadModel() const {
+  // The WebAssembly MVP does not yet support threads; for now, use the
+  // "single" threading model, which lowers atomics to non-atomic operations.
+  // When threading support is standardized and implemented in popular engines,
+  // this override should be removed.
+  return "single";
+}
+
 Tool *WebAssembly::buildLinker() const {
   return new tools::wasm::Linker(*this);
 }