[WebAssembly] Add crt1.o when calling lld

[sbc100]

Summary

Also, for OS unknown targets like wasm, don't include
'unknown' in the library path. This is a fix for the
rL316719.

[sbc100]

• rebase

lib/Driver/ToolChain.cpp

static StringRef getArchNameForCompilerRTLib(const ToolChain &TC,
   if (TC.getArch() == llvm::Triple::x86 && Triple.isAndroid())
     return "i686";
 
   return llvm::Triple::getArchTypeName(TC.getArch());
 }
 
 std::string ToolChain::getCompilerRTPath() const {
   SmallString<128> Path(getDriver().ResourceDir);
-  StringRef OSLibName;
-  if (Triple.isOSFreeBSD())
-    OSLibName = "freebsd";
-  else if (Triple.isOSBinFormatWasm())
-    OSLibName = "wasm";
-  else
-    OSLibName = getOS();
+  if (Triple.isOSUnknown()) {
+    llvm::sys::path::append(Path, "lib");
+  } else {
+    StringRef OSLibName = Triple.isOSFreeBSD() ? "freebsd" : getOS();
     llvm::sys::path::append(Path, "lib", OSLibName);
+  }
   return Path.str();
 }
 
 std::string ToolChain::getCompilerRT(const ArgList &Args, StringRef Component,
                                      bool Shared) const {
   const llvm::Triple &TT = getTriple();
   const char *Env = TT.isAndroid() ? "-android" : "";
   bool IsITANMSVCWindows =

lib/Driver/ToolChains/WebAssembly.cpp

void wasm::Linker::ConstructJob(Compilation &C, const JobAction &JA,
   CmdArgs.push_back("wasm");
 
   if (Args.hasArg(options::OPT_s))
     CmdArgs.push_back("--strip-all");
 
   Args.AddAllArgs(CmdArgs, options::OPT_L);
   ToolChain.AddFilePathLibArgs(Args, CmdArgs);
 
+  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 (ToolChain.ShouldLinkCXXStdlib(Args))
       ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);
 
     if (Args.hasArg(options::OPT_pthread))
       CmdArgs.push_back("-lpthread");

test/Driver/wasm-toolchain.c

 
 // RUN: %clang %s -### -target wasm32-unknown-unknown -fvisibility=default 2>&1 | FileCheck -check-prefix=FVISIBILITY_DEFAULT %s
 // FVISIBILITY_DEFAULT-NOT: hidden
 
 // A basic C link command-line.
 
 // RUN: %clang -### -no-canonical-prefixes -target wasm32-unknown-unknown --sysroot=/foo %s 2>&1 | FileCheck -check-prefix=LINK %s
 // LINK: clang{{.*}}" "-cc1" {{.*}} "-o" "[[temp:[^"]*]]"
-// LINK: lld{{.*}}" "-flavor" "wasm" "-L/foo/lib" "[[temp]]" "-allow-undefined-file" "wasm.syms" "-lc" "{{.*[/\\]}}libclang_rt.builtins-wasm32.a" "-o" "a.out"
+// LINK: lld{{.*}}" "-flavor" "wasm" "-L/foo/lib" "crt1.o" "[[temp]]" "-allow-undefined-file" "wasm.syms" "-lc" "{{.*[/\\]}}libclang_rt.builtins-wasm32.a" "-o" "a.out"
 
 // A basic C link command-line with optimization.
 
 // RUN: %clang -### -O2 -no-canonical-prefixes -target wasm32-unknown-unknown --sysroot=/foo %s 2>&1 | FileCheck -check-prefix=LINK_OPT %s
 // LINK_OPT: clang{{.*}}" "-cc1" {{.*}} "-o" "[[temp:[^"]*]]"
-// LINK_OPT: lld{{.*}}" "-flavor" "wasm" "-L/foo/lib" "[[temp]]" "-allow-undefined-file" "wasm.syms" "-lc" "{{.*[/\\]}}libclang_rt.builtins-wasm32.a" "-o" "a.out"
+// LINK_OPT: lld{{.*}}" "-flavor" "wasm" "-L/foo/lib" "crt1.o" "[[temp]]" "-allow-undefined-file" "wasm.syms" "-lc" "{{.*[/\\]}}libclang_rt.builtins-wasm32.a" "-o" "a.out"