[clang] [Clang][Driver] Revise Cygwin ToolChain to call linker directly (PR #147960)

[Tomohiro Kashiwada via cfe-commits]

================
@@ -107,3 +110,294 @@ 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();
+  }
+
+  Arg *SubsysArg =
+      Args.getLastArg(options::OPT_mwindows, options::OPT_mconsole);
+  if (SubsysArg && SubsysArg->getOption().matches(options::OPT_mwindows)) {
+    CmdArgs.push_back("--subsystem");
+    CmdArgs.push_back("windows");
+  } else if (SubsysArg &&
+             SubsysArg->getOption().matches(options::OPT_mconsole)) {
+    CmdArgs.push_back("--subsystem");
+    CmdArgs.push_back("console");
+  }
+
+  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");
+
+  if (Args.hasArg(options::OPT_mdll))
+    CmdArgs.push_back("--dll");
+  else if (Args.hasArg(options::OPT_shared))
+    CmdArgs.push_back("--shared");
+  if (Args.hasArg(options::OPT_static))
+    CmdArgs.push_back("-Bstatic");
+  else
+    CmdArgs.push_back("-Bdynamic");
+
+  CmdArgs.push_back("--dll-search-prefix=cyg");
+
+  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");
+    }
+
+    const bool IsShared = Args.hasArg(options::OPT_shared);
+    if (IsShared) {
+      CmdArgs.push_back("-e");
+      CmdArgs.push_back(ToolChain.getArch() == llvm::Triple::x86
+                            ? "__cygwin_dll_entry at 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);
+
+  bool saw_high_entropy_va = false;
+  for (const char *Arg : CmdArgs)
+    if (StringRef(Arg) == "--high-entropy-va" ||
----------------
kikairoya wrote:

Is this check needed? Users want to override can use `-Wl,--high-entropy-va`. If you really want to handle this here, `options::OPT_fhigh_entropy_va` should be added.

https://github.com/llvm/llvm-project/pull/147960