Revert "[RISCV] Support mutilib in baremetal environment"

This reverts commit df876a0.
Clang::riscv32-toolchain.c Clang::riscv64-toolchain.c fails on Windows.

Author: zakk0610

clang/lib/Driver/ToolChains/Gnu.cpp

@@ -1503,65 +1503,9 @@ static bool findMSP430Multilibs(const Driver &D,
   return false;
 }
 
-static void findRISCVBareMetalMultilibs(const Driver &D,
-                                        const llvm::Triple &TargetTriple,
-                                        StringRef Path, const ArgList &Args,
-                                        DetectedMultilibs &Result) {
-  FilterNonExistent NonExistent(Path, "/crtbegin.o", D.getVFS());
-  struct RiscvMultilib {
-    StringRef march;
-    StringRef mabi;
-  };
-  // currently only support the set of multilibs like riscv-gnu-toolchain does.
-  // TODO: support MULTILIB_REUSE
-  SmallVector<RiscvMultilib, 8> RISCVMultilibSet = {
-      {"rv32i", "ilp32"},     {"rv32im", "ilp32"},     {"rv32iac", "ilp32"},
-      {"rv32imac", "ilp32"},  {"rv32imafc", "ilp32f"}, {"rv64imac", "lp64"},
-      {"rv64imafdc", "lp64d"}};
-
-  std::vector<Multilib> Ms;
-  for (auto Element : RISCVMultilibSet) {
-    // multilib path rule is ${march}/${mabi}
-    Ms.emplace_back(
-        makeMultilib((Twine(Element.march) + "/" + Twine(Element.mabi)).str())
-            .flag(Twine("+march=", Element.march).str())
-            .flag(Twine("+mabi=", Element.mabi).str()));
-  }
-  MultilibSet RISCVMultilibs =
-      MultilibSet()
-          .Either(ArrayRef<Multilib>(Ms))
-          .FilterOut(NonExistent)
-          .setFilePathsCallback([](const Multilib &M) {
-            return std::vector<std::string>(
-                {M.gccSuffix(),
-                 "/../../../../riscv64-unknown-elf/lib" + M.gccSuffix(),
-                 "/../../../../riscv32-unknown-elf/lib" + M.gccSuffix()});
-          });
-
-
-  Multilib::flags_list Flags;
-  llvm::StringSet<> Added_ABIs;
-  StringRef ABIName = tools::riscv::getRISCVABI(Args, TargetTriple);
-  StringRef MArch = tools::riscv::getRISCVArch(Args, TargetTriple);
-  for (auto Element : RISCVMultilibSet) {
-    addMultilibFlag(MArch == Element.march,
-                    Twine("march=", Element.march).str().c_str(), Flags);
-    if (!Added_ABIs.count(Element.mabi)) {
-      Added_ABIs.insert(Element.mabi);
-      addMultilibFlag(ABIName == Element.mabi,
-                      Twine("mabi=", Element.mabi).str().c_str(), Flags);
-    }
-  }
-
-  if (RISCVMultilibs.select(Flags, Result.SelectedMultilib))
-    Result.Multilibs = RISCVMultilibs;
-}
-
 static void findRISCVMultilibs(const Driver &D,
                                const llvm::Triple &TargetTriple, StringRef Path,
                                const ArgList &Args, DetectedMultilibs &Result) {
-  if (TargetTriple.getOS() == llvm::Triple::UnknownOS)
-    return findRISCVBareMetalMultilibs(D, TargetTriple, Path, Args, Result);
 
   FilterNonExistent NonExistent(Path, "/crtbegin.o", D.getVFS());
   Multilib Ilp32 = makeMultilib("lib32/ilp32").flag("+m32").flag("+mabi=ilp32");

clang/lib/Driver/ToolChains/RISCVToolchain.cpp

@@ -22,39 +22,19 @@ using namespace clang::driver::tools;
 using namespace clang;
 using namespace llvm::opt;
 
-static void addMultilibsFilePaths(const Driver &D, const MultilibSet &Multilibs,
-                                  const Multilib &Multilib,
-                                  StringRef InstallPath,
-                                  ToolChain::path_list &Paths) {
-  if (const auto &PathsCallback = Multilibs.filePathsCallback())
-    for (const auto &Path : PathsCallback(Multilib))
-      addPathIfExists(D, InstallPath + Path, Paths);
-}
-
 /// RISCV Toolchain
 RISCVToolChain::RISCVToolChain(const Driver &D, const llvm::Triple &Triple,
                                const ArgList &Args)
     : Generic_ELF(D, Triple, Args) {
   GCCInstallation.init(Triple, Args);
+  getFilePaths().push_back(computeSysRoot() + "/lib");
   if (GCCInstallation.isValid()) {
-    Multilibs = GCCInstallation.getMultilibs();
-    SelectedMultilib = GCCInstallation.getMultilib();
-    path_list &Paths = getFilePaths();
-    // Add toolchain/multilib specific file paths.
-    addMultilibsFilePaths(D, Multilibs, SelectedMultilib,
-                          GCCInstallation.getInstallPath(), Paths);
     getFilePaths().push_back(GCCInstallation.getInstallPath().str());
-    ToolChain::path_list &PPaths = getProgramPaths();
-    // Multilib cross-compiler GCC installations put ld in a triple-prefixed
-    // directory off of the parent of the GCC installation.
-    PPaths.push_back(Twine(GCCInstallation.getParentLibPath() + "/../" +
-                           GCCInstallation.getTriple().str() + "/bin")
-                         .str());
-    PPaths.push_back((GCCInstallation.getParentLibPath() + "/../bin").str());
+    getProgramPaths().push_back(
+        (GCCInstallation.getParentLibPath() + "/../bin").str());
   } else {
     getProgramPaths().push_back(D.Dir);
   }
-  getFilePaths().push_back(computeSysRoot() + "/lib");
 }
 
 Tool *RISCVToolChain::buildLinker() const {
@@ -125,14 +105,6 @@ void RISCV::Linker::ConstructJob(Compilation &C, const JobAction &JA,
   if (!D.SysRoot.empty())
     CmdArgs.push_back(Args.MakeArgString("--sysroot=" + D.SysRoot));
 
-  bool IsRV64 = ToolChain.getArch() == llvm::Triple::riscv64;
-  CmdArgs.push_back("-m");
-  if (IsRV64) {
-    CmdArgs.push_back("elf64lriscv");
-  } else {
-    CmdArgs.push_back("elf32lriscv");
-  }
-
   std::string Linker = getToolChain().GetProgramPath(getShortName());
 
   bool WantCRTs =