[clang] [UEFI] X86_64 UEFI Clang Driver (PR #76838)

[Fangrui Song via cfe-commits]

================
@@ -0,0 +1,115 @@
+//===--- UEFI.h - UEFI ToolChain Implementations ----------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "UEFI.h"
+#include "CommonArgs.h"
+#include "Darwin.h"
+#include "clang/Basic/CharInfo.h"
+#include "clang/Basic/Version.h"
+#include "clang/Config/config.h"
+#include "clang/Driver/Compilation.h"
+#include "clang/Driver/Driver.h"
+#include "clang/Driver/Options.h"
+#include "clang/Driver/SanitizerArgs.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/ADT/StringSwitch.h"
+#include "llvm/Option/Arg.h"
+#include "llvm/Option/ArgList.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/VirtualFileSystem.h"
+#include "llvm/TargetParser/Host.h"
+
+using namespace clang::driver;
+using namespace clang::driver::toolchains;
+using namespace clang;
+using namespace llvm::opt;
+
+UEFI::UEFI(const Driver &D, const llvm::Triple &Triple, const ArgList &Args)
+    : ToolChain(D, Triple, Args) {
+  getProgramPaths().push_back(getDriver().getInstalledDir());
+  if (getDriver().getInstalledDir() != getDriver().Dir)
+    getProgramPaths().push_back(getDriver().Dir);
+}
+
+Tool *UEFI::buildLinker() const { return new tools::uefi::Linker(*this); }
+
+void tools::uefi::Linker::ConstructJob(Compilation &C, const JobAction &JA,
+                                       const InputInfo &Output,
+                                       const InputInfoList &Inputs,
+                                       const ArgList &Args,
+                                       const char *LinkingOutput) const {
+  ArgStringList CmdArgs;
+
+  auto &TC = static_cast<const toolchains::UEFI &>(getToolChain());
+
+  assert((Output.isFilename() || Output.isNothing()) && "invalid output");
+  if (Output.isFilename())
+    CmdArgs.push_back(
+        Args.MakeArgString(std::string("-out:") + Output.getFilename()));
+
+  CmdArgs.push_back("-nologo");
+
+  // TODO: Other UEFI binary subsystems that are currently unsupported:
+  // efi_boot_service_driver, efi_rom, efi_runtime_driver.
+  CmdArgs.push_back("-subsystem:efi_application");
+
+  // Default entry function name according to the TianoCore reference
+  // implementation is EfiMain.
+  // TODO: Provide a flag to override the entry function name.
+  CmdArgs.push_back("-entry:EfiMain");
+
+  // "Terminal Service Aware" flag is not needed for UEFI applications.
+  CmdArgs.push_back("-tsaware:no");
+
+  // EFI_APPLICATION to be linked as DLL by default.
+  CmdArgs.push_back("-dll");
+
+  if (Args.hasArg(options::OPT_g_Group, options::OPT__SLASH_Z7))
+    CmdArgs.push_back("-debug");
+
+  Args.AddAllArgValues(CmdArgs, options::OPT__SLASH_link);
+
+  // Add filenames, libraries, and other linker inputs.
+  for (const auto &Input : Inputs) {
+    if (Input.isFilename()) {
+      CmdArgs.push_back(Input.getFilename());
+      continue;
+    }
+
+    const Arg &A = Input.getInputArg();
+    if (A.getOption().matches(options::OPT_l)) {
+      StringRef Lib = A.getValue();
+      const char *LinkLibArg;
+      if (Lib.ends_with(".lib"))
+        LinkLibArg = Args.MakeArgString(Lib);
+      else
+        LinkLibArg = Args.MakeArgString(Lib + ".lib");
+      CmdArgs.push_back(LinkLibArg);
+      continue;
+    }
+
+    // Otherwise, this is some other kind of linker input option like -Wl, -z,
+    // or -L.
+    A.renderAsInput(Args, CmdArgs);
+  }
+
+  // This should ideally be handled by ToolChain::GetLinkerPath but we need
+  // to special case some linker paths. In the case of lld, we need to
+  // translate 'lld' into 'lld-link'.
+  StringRef Linker =
+      Args.getLastArgValue(options::OPT_fuse_ld_EQ, CLANG_DEFAULT_LINKER);
+  if (Linker.empty() || Linker.equals_insensitive("lld"))
----------------
MaskRay wrote:

If we don't model after existing constraints (e.g. MSVC), avoid `_insensitive`

https://github.com/llvm/llvm-project/pull/76838