[Clang][Driver] Revise Cygwin ToolChain to call linker directly

...so that libc++, compiler-rt, and libunwind can be used by the
options: -stdlib=libc++, -rtlib=compiler-rt, and -unwindlib=libunwind
respectively. Along with this change, the test for this driver is also
trimmed a bit.

This is a follow-up patch to the commit 52924a2.

Signed-off-by: Takashi Yano <takashi.yano@nifty.ne.jp>

Author: tyan0

clang/lib/Driver/ToolChain.cpp

@@ -684,6 +684,8 @@ static StringRef getArchNameForCompilerRTLib(const ToolChain &TC,
 StringRef ToolChain::getOSLibName() const {
   if (Triple.isOSDarwin())
     return "darwin";
+  if (Triple.isWindowsCygwinEnvironment())
+    return "cygwin";
 
   switch (Triple.getOS()) {
   case llvm::Triple::FreeBSD:
@@ -1504,6 +1506,7 @@ void ToolChain::AddCXXStdlibLibArgs(const ArgList &Args,
   switch (Type) {
   case ToolChain::CST_Libcxx:
     CmdArgs.push_back("-lc++");
+    CmdArgs.push_back("-lc++abi");
     if (Args.hasArg(options::OPT_fexperimental_library))
       CmdArgs.push_back("-lc++experimental");
     break;

clang/lib/Driver/ToolChains/Cygwin.cpp

@@ -9,6 +9,7 @@
 #include "Cygwin.h"
 #include "clang/Config/config.h"
 #include "clang/Driver/CommonArgs.h"
+#include "clang/Driver/Compilation.h"
 #include "clang/Driver/Driver.h"
 #include "clang/Driver/Options.h"
 #include "llvm/Support/Path.h"
@@ -30,6 +31,8 @@ Cygwin::Cygwin(const Driver &D, const llvm::Triple &Triple, const ArgList &Args)
   Generic_GCC::PushPPaths(PPaths);
 
   path_list &Paths = getFilePaths();
+  if (GCCInstallation.isValid())
+    Paths.push_back(GCCInstallation.getInstallPath().str());
 
   Generic_GCC::AddMultiarchPaths(D, SysRoot, "lib", Paths);
 
@@ -107,3 +110,282 @@ void Cygwin::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
   addExternCSystemInclude(DriverArgs, CC1Args, SysRoot + "/usr/include");
   addExternCSystemInclude(DriverArgs, CC1Args, SysRoot + "/usr/include/w32api");
 }
+
+static bool getStaticPIE(const ArgList &Args, const ToolChain &TC) {
+  bool HasStaticPIE = Args.hasArg(options::OPT_static_pie);
+  if (HasStaticPIE && Args.hasArg(options::OPT_no_pie)) {
+    const Driver &D = TC.getDriver();
+    const llvm::opt::OptTable &Opts = D.getOpts();
+    StringRef StaticPIEName = Opts.getOptionName(options::OPT_static_pie);
+    StringRef NoPIEName = Opts.getOptionName(options::OPT_nopie);
+    D.Diag(diag::err_drv_cannot_mix_options) << StaticPIEName << NoPIEName;
+  }
+  return HasStaticPIE;
+}
+
+static bool getStatic(const ArgList &Args) {
+  return Args.hasArg(options::OPT_static) &&
+         !Args.hasArg(options::OPT_static_pie);
+}
+
+void cygwin::Linker::ConstructJob(Compilation &C, const JobAction &JA,
+                                  const InputInfo &Output,
+                                  const InputInfoList &Inputs,
+                                  const ArgList &Args,
+                                  const char *LinkingOutput) const {
+  const auto &ToolChain = getToolChain();
+  const Driver &D = ToolChain.getDriver();
+
+  const bool IsIAMCU = ToolChain.getTriple().isOSIAMCU();
+  const bool IsVE = ToolChain.getTriple().isVE();
+  const bool IsStaticPIE = getStaticPIE(Args, ToolChain);
+  const bool IsStatic = getStatic(Args);
+
+  ArgStringList CmdArgs;
+
+  // Silence warning for "clang -g foo.o -o foo"
+  Args.ClaimAllArgs(options::OPT_g_Group);
+  // and "clang -emit-llvm foo.o -o foo"
+  Args.ClaimAllArgs(options::OPT_emit_llvm);
+  // and for "clang -w foo.o -o foo". Other warning options are already
+  // handled somewhere else.
+  Args.ClaimAllArgs(options::OPT_w);
+
+  if (!D.SysRoot.empty())
+    CmdArgs.push_back(Args.MakeArgString("--sysroot=" + D.SysRoot));
+
+  if (Args.hasArg(options::OPT_s))
+    CmdArgs.push_back("-s");
+
+  CmdArgs.push_back("-m");
+  switch (ToolChain.getArch()) {
+  case llvm::Triple::x86:
+    CmdArgs.push_back("i386pe");
+    break;
+  case llvm::Triple::x86_64:
+    CmdArgs.push_back("i386pep");
+    break;
+  case llvm::Triple::arm:
+  case llvm::Triple::thumb:
+    // FIXME: this is incorrect for WinCE
+    CmdArgs.push_back("thumb2pe");
+    break;
+  case llvm::Triple::aarch64:
+    if (ToolChain.getEffectiveTriple().isWindowsArm64EC())
+      CmdArgs.push_back("arm64ecpe");
+    else
+      CmdArgs.push_back("arm64pe");
+    break;
+  default:
+    D.Diag(diag::err_target_unknown_triple)
+        << ToolChain.getEffectiveTriple().str();
+  }
+
+  CmdArgs.push_back("--wrap=_Znwm");
+  CmdArgs.push_back("--wrap=_Znam");
+  CmdArgs.push_back("--wrap=_ZdlPv");
+  CmdArgs.push_back("--wrap=_ZdaPv");
+  CmdArgs.push_back("--wrap=_ZnwmRKSt9nothrow_t");
+  CmdArgs.push_back("--wrap=_ZnamRKSt9nothrow_t");
+  CmdArgs.push_back("--wrap=_ZdlPvRKSt9nothrow_t");
+  CmdArgs.push_back("--wrap=_ZdaPvRKSt9nothrow_t");
+
+  const bool IsShared = Args.hasArg(options::OPT_shared);
+  if (IsShared)
+    CmdArgs.push_back("-shared");
+  bool IsPIE = false;
+  if (IsStaticPIE) {
+    CmdArgs.push_back("-static");
+    CmdArgs.push_back("-pie");
+    CmdArgs.push_back("--no-dynamic-linker");
+    CmdArgs.push_back("-z");
+    CmdArgs.push_back("text");
+  } else if (IsStatic) {
+    CmdArgs.push_back("-static");
+  } else if (!Args.hasArg(options::OPT_r)) {
+    if (Args.hasArg(options::OPT_rdynamic))
+      CmdArgs.push_back("-export-dynamic");
+    if (!IsShared) {
+      IsPIE = Args.hasFlag(options::OPT_pie, options::OPT_no_pie,
+                           ToolChain.isPIEDefault(Args));
+      if (IsPIE)
+        CmdArgs.push_back("-pie");
+    }
+  }
+
+  CmdArgs.push_back("-o");
+  CmdArgs.push_back(Output.getFilename());
+
+  if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles,
+                   options::OPT_r)) {
+    if (IsVE) {
+      CmdArgs.push_back("-z");
+      CmdArgs.push_back("max-page-size=0x4000000");
+    }
+
+    if (IsShared) {
+      CmdArgs.push_back("-e");
+      CmdArgs.push_back(ToolChain.getTriple().isArch32Bit()
+                            ? "__cygwin_dll_entry@12"
+                            : "_cygwin_dll_entry");
+      CmdArgs.push_back("--enable-auto-image-base");
+    }
+
+    if (!IsShared)
+      CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crt0.o")));
+    if (ToolChain.GetRuntimeLibType(Args) == ToolChain::RLT_CompilerRT) {
+      std::string crtbegin =
+          ToolChain.getCompilerRT(Args, "crtbegin", ToolChain::FT_Object);
+      if (ToolChain.getVFS().exists(crtbegin)) {
+        std::string P;
+        P = crtbegin;
+        CmdArgs.push_back(Args.MakeArgString(P));
+      }
+    }
+    if (IsShared)
+      CmdArgs.push_back(
+          Args.MakeArgString(ToolChain.GetFilePath("crtbeginS.o")));
+    else
+      CmdArgs.push_back(
+          Args.MakeArgString(ToolChain.GetFilePath("crtbegin.o")));
+
+    // Add crtfastmath.o if available and fast math is enabled.
+    ToolChain.addFastMathRuntimeIfAvailable(Args, CmdArgs);
+  }
+
+  Args.addAllArgs(CmdArgs, {options::OPT_L, options::OPT_u});
+
+  ToolChain.AddFilePathLibArgs(Args, CmdArgs);
+
+  if (D.isUsingLTO())
+    tools::addLTOOptions(ToolChain, Args, CmdArgs, Output, Inputs,
+                         D.getLTOMode() == LTOK_Thin);
+
+  if (Args.hasArg(options::OPT_Z_Xlinker__no_demangle))
+    CmdArgs.push_back("--no-demangle");
+
+  bool NeedsSanitizerDeps =
+      tools::addSanitizerRuntimes(ToolChain, Args, CmdArgs);
+  bool NeedsXRayDeps = tools::addXRayRuntime(ToolChain, Args, CmdArgs);
+  tools::addLinkerCompressDebugSectionsOption(ToolChain, Args, CmdArgs);
+  tools::AddLinkerInputs(ToolChain, Inputs, Args, CmdArgs, JA);
+
+  tools::addHIPRuntimeLibArgs(ToolChain, C, Args, CmdArgs);
+
+  // The profile runtime also needs access to system libraries.
+  getToolChain().addProfileRTLibs(Args, CmdArgs);
+
+  if (D.CCCIsCXX() &&
+      !Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs,
+                   options::OPT_r)) {
+    if (ToolChain.ShouldLinkCXXStdlib(Args)) {
+      bool OnlyLibstdcxxStatic = Args.hasArg(options::OPT_static_libstdcxx) &&
+                                 !Args.hasArg(options::OPT_static);
+      if (OnlyLibstdcxxStatic)
+        CmdArgs.push_back("-Bstatic");
+      ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);
+      if (OnlyLibstdcxxStatic)
+        CmdArgs.push_back("-Bdynamic");
+    }
+    CmdArgs.push_back("-lm");
+  }
+
+  // Silence warnings when linking C code with a C++ '-stdlib' argument.
+  Args.ClaimAllArgs(options::OPT_stdlib_EQ);
+
+  // Additional linker set-up and flags for Fortran. This is required in order
+  // to generate executables. As Fortran runtime depends on the C runtime,
+  // these dependencies need to be listed before the C runtime below (i.e.
+  // AddRunTimeLibs).
+  if (D.IsFlangMode() &&
+      !Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
+    ToolChain.addFortranRuntimeLibraryPath(Args, CmdArgs);
+    ToolChain.addFortranRuntimeLibs(Args, CmdArgs);
+    CmdArgs.push_back("-lm");
+  }
+
+  if (!Args.hasArg(options::OPT_nostdlib, options::OPT_r)) {
+    if (!Args.hasArg(options::OPT_nodefaultlibs)) {
+      if (IsStatic || IsStaticPIE)
+        CmdArgs.push_back("--start-group");
+
+      if (NeedsSanitizerDeps)
+        tools::linkSanitizerRuntimeDeps(ToolChain, Args, CmdArgs);
+
+      if (NeedsXRayDeps)
+        tools::linkXRayRuntimeDeps(ToolChain, Args, CmdArgs);
+
+      bool WantPthread = Args.hasArg(options::OPT_pthread) ||
+                         Args.hasArg(options::OPT_pthreads);
+
+      // Use the static OpenMP runtime with -static-openmp
+      bool StaticOpenMP = Args.hasArg(options::OPT_static_openmp) &&
+                          !Args.hasArg(options::OPT_static);
+
+      // FIXME: Only pass GompNeedsRT = true for platforms with libgomp that
+      // require librt. Most modern Linux platforms do, but some may not.
+      if (tools::addOpenMPRuntime(C, CmdArgs, ToolChain, Args, StaticOpenMP,
+                                  JA.isHostOffloading(Action::OFK_OpenMP),
+                                  /* GompNeedsRT= */ true))
+        // OpenMP runtimes implies pthreads when using the GNU toolchain.
+        // FIXME: Does this really make sense for all GNU toolchains?
+        WantPthread = true;
+
+      tools::AddRunTimeLibs(ToolChain, D, CmdArgs, Args);
+
+      if (WantPthread)
+        CmdArgs.push_back("-lpthread");
+
+      if (Args.hasArg(options::OPT_fsplit_stack))
+        CmdArgs.push_back("--wrap=pthread_create");
+
+      if (!Args.hasArg(options::OPT_nolibc))
+        CmdArgs.push_back("-lc");
+
+      // Cygwin specific
+      CmdArgs.push_back("-lcygwin");
+      CmdArgs.push_back("-ladvapi32");
+      CmdArgs.push_back("-lshell32");
+      CmdArgs.push_back("-luser32");
+      CmdArgs.push_back("-lkernel32");
+
+      // Add IAMCU specific libs, if needed.
+      if (IsIAMCU)
+        CmdArgs.push_back("-lgloss");
+
+      if (IsStatic || IsStaticPIE)
+        CmdArgs.push_back("--end-group");
+      else
+        tools::AddRunTimeLibs(ToolChain, D, CmdArgs, Args);
+
+      // Add IAMCU specific libs (outside the group), if needed.
+      if (IsIAMCU) {
+        CmdArgs.push_back("--as-needed");
+        CmdArgs.push_back("-lsoftfp");
+        CmdArgs.push_back("--no-as-needed");
+      }
+    }
+
+    if (!Args.hasArg(options::OPT_nostartfiles) && !IsIAMCU) {
+      if (ToolChain.GetRuntimeLibType(Args) == ToolChain::RLT_CompilerRT) {
+        std::string crtend =
+            ToolChain.getCompilerRT(Args, "crtend", ToolChain::FT_Object);
+        if (ToolChain.getVFS().exists(crtend)) {
+          std::string P;
+          P = crtend;
+          CmdArgs.push_back(Args.MakeArgString(P));
+        }
+      }
+      CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crtend.o")));
+    }
+  }
+
+  Args.addAllArgs(CmdArgs, {options::OPT_T, options::OPT_t});
+
+  const char *Exec = Args.MakeArgString(ToolChain.GetLinkerPath());
+  C.addCommand(std::make_unique<Command>(JA, *this,
+                                         ResponseFileSupport::AtFileCurCP(),
+                                         Exec, CmdArgs, Inputs, Output));
+}
+
+auto Cygwin::buildLinker() const -> Tool * { return new cygwin::Linker(*this); }

clang/lib/Driver/ToolChains/Cygwin.h

@@ -27,7 +27,25 @@ class LLVM_LIBRARY_VISIBILITY Cygwin : public Generic_GCC {
   void
   AddClangSystemIncludeArgs(const llvm::opt::ArgList &DriverArgs,
                             llvm::opt::ArgStringList &CC1Args) const override;
+
+protected:
+  Tool *buildLinker() const override;
+};
+
+namespace cygwin {
+class LLVM_LIBRARY_VISIBILITY Linker final : public Tool {
+public:
+  Linker(const ToolChain &TC) : Tool("cygwin::Linker", "linker", TC) {}
+
+  bool hasIntegratedCPP() const override { return false; }
+  bool isLinkJob() const override { return true; }
+
+  void ConstructJob(Compilation &C, const JobAction &JA,
+                    const InputInfo &Output, const InputInfoList &Inputs,
+                    const llvm::opt::ArgList &TCArgs,
+                    const char *LinkingOutput) const override;
 };
+} // end namespace cygwin
 
 } // end namespace toolchains
 } // end namespace driver

clang/test/Driver/Inputs/basic_cross_cygwin_tree/usr/lib/gcc/i686-pc-msys/10/crtend.o

@@ -15,19 +15,19 @@
 // CHECK-SAME: {{^}} "-internal-externc-isystem" "[[SYSROOT]]/usr/include/w32api"
 // CHECK-SAME: "-femulated-tls"
 // CHECK-SAME: "-exception-model=dwarf"
-// CHECK:      "{{.*}}gcc{{(\.exe)?}}"
-// CHECK-SAME: "-m32"
+// CHECK:      "{{.*}}ld{{(\.exe)?}}"
+// CHECK-SAME: "-m" "i386pe"
 
 // RUN: %clang -### %s --target=i686-pc-cygwin --sysroot=%S/Inputs/basic_cygwin_tree \
 // RUN:   --stdlib=platform -static 2>&1 | FileCheck --check-prefix=CHECK-STATIC %s
 // CHECK-STATIC:      "-cc1" "-triple" "i686-pc-windows-cygnus"
 // CHECK-STATIC-SAME: "-static-define"
-// CHECK-STATIC:      "{{.*}}gcc{{(\.exe)?}}"
+// CHECK-STATIC:      "{{.*}}ld{{(\.exe)?}}"
 // CHECK-STATIC-SAME: "-static"
 
 // RUN: %clang -### %s --target=i686-pc-cygwin --sysroot=%S/Inputs/basic_cygwin_tree \
 // RUN:   -shared 2>&1 | FileCheck --check-prefix=CHECK-SHARED %s
-// CHECK-SHARED:      "{{.*}}gcc{{(\.exe)?}}"
+// CHECK-SHARED:      "{{.*}}ld{{(\.exe)?}}"
 // CHECK-SHARED-SAME: "-shared"
 
 // RUN: %clang -### -o %t %s 2>&1 -no-integrated-as -fuse-ld=ld \
@@ -54,19 +54,19 @@
 // CHECK-64-SAME: {{^}} "-internal-externc-isystem" "[[SYSROOT]]/usr/include/w32api"
 // CHECK-64-SAME: "-femulated-tls"
 // CHECK-64-SAME: "-exception-model=seh"
-// CHECK-64:      "{{.*}}gcc{{(\.exe)?}}"
-// CHECK-64-SAME: "-m64"
+// CHECK-64:      "{{.*}}ld{{(\.exe)?}}"
+// CHECK-64-SAME: "-m" "i386pep"
 
 // RUN: %clang -### %s --target=x86_64-pc-cygwin --sysroot=%S/Inputs/basic_cygwin_tree \
 // RUN:   --stdlib=platform -static 2>&1 | FileCheck --check-prefix=CHECK-64-STATIC %s
 // CHECK-64-STATIC:      "-cc1" "-triple" "x86_64-pc-windows-cygnus"
 // CHECK-64-STATIC-SAME: "-static-define"
-// CHECK-64-STATIC:      "{{.*}}gcc{{(\.exe)?}}"
+// CHECK-64-STATIC:      "{{.*}}ld{{(\.exe)?}}"
 // CHECK-64-STATIC-SAME: "-static"
 
 // RUN: %clang -### %s --target=x86_64-pc-cygwin --sysroot=%S/Inputs/basic_cygwin_tree \
 // RUN:   -shared 2>&1 | FileCheck --check-prefix=CHECK-64-SHARED %s
-// CHECK-64-SHARED:      "{{.*}}gcc{{(\.exe)?}}"
+// CHECK-64-SHARED:      "{{.*}}ld{{(\.exe)?}}"
 // CHECK-64-SHARED-SAME: "-shared"
 
 // RUN: %clang -### -o %t %s 2>&1 -no-integrated-as -fuse-ld=ld \