[Driver] Add toolchain for X86_64 UEFI target (#76838)

Introduce changes necessary for UEFI X86_64 target Clang driver.
Addressed the review comments originally suggested in Phabricator.

Differential Revision: https://reviews.llvm.org/D159541

Author: Prabhuk

clang/lib/Basic/Targets.cpp

@@ -613,6 +613,9 @@ std::unique_ptr<TargetInfo> AllocateTarget(const llvm::Triple &Triple,
     case llvm::Triple::Solaris:
       return std::make_unique<SolarisTargetInfo<X86_64TargetInfo>>(Triple,
                                                                    Opts);
+    case llvm::Triple::UEFI:
+      return std::make_unique<UEFIX86_64TargetInfo>(Triple, Opts);
+
     case llvm::Triple::Win32: {
       switch (Triple.getEnvironment()) {
       case llvm::Triple::Cygnus:

clang/lib/Basic/Targets/OSTargets.h

@@ -778,6 +778,21 @@ class LLVM_LIBRARY_VISIBILITY ZOSTargetInfo : public OSTargetInfo<Target> {
   }
 };
 
+// UEFI target
+template <typename Target>
+class LLVM_LIBRARY_VISIBILITY UEFITargetInfo : public OSTargetInfo<Target> {
+protected:
+  void getOSDefines(const LangOptions &Opts, const llvm::Triple &Triple,
+                    MacroBuilder &Builder) const override {}
+
+public:
+  UEFITargetInfo(const llvm::Triple &Triple, const TargetOptions &Opts)
+      : OSTargetInfo<Target>(Triple, Opts) {
+    this->WCharType = TargetInfo::UnsignedShort;
+    this->WIntType = TargetInfo::UnsignedShort;
+  }
+};
+
 void addWindowsDefines(const llvm::Triple &Triple, const LangOptions &Opts,
                        MacroBuilder &Builder);
 

clang/lib/Basic/Targets/X86.h

@@ -814,6 +814,43 @@ class LLVM_LIBRARY_VISIBILITY X86_64TargetInfo : public X86TargetInfo {
   }
 };
 
+// x86-64 UEFI target
+class LLVM_LIBRARY_VISIBILITY UEFIX86_64TargetInfo
+    : public UEFITargetInfo<X86_64TargetInfo> {
+public:
+  UEFIX86_64TargetInfo(const llvm::Triple &Triple, const TargetOptions &Opts)
+      : UEFITargetInfo<X86_64TargetInfo>(Triple, Opts) {
+    this->TheCXXABI.set(TargetCXXABI::Microsoft);
+    this->MaxTLSAlign = 8192u * this->getCharWidth();
+    this->resetDataLayout("e-m:w-p270:32:32-p271:32:32-p272:64:64-"
+                          "i64:64-i128:128-f80:128-n8:16:32:64-S128");
+  }
+
+  void getTargetDefines(const LangOptions &Opts,
+                        MacroBuilder &Builder) const override {
+    getOSDefines(Opts, X86TargetInfo::getTriple(), Builder);
+  }
+
+  BuiltinVaListKind getBuiltinVaListKind() const override {
+    return TargetInfo::CharPtrBuiltinVaList;
+  }
+
+  CallingConvCheckResult checkCallingConvention(CallingConv CC) const override {
+    switch (CC) {
+    case CC_C:
+    case CC_Win64:
+      return CCCR_OK;
+    default:
+      return CCCR_Warning;
+    }
+  }
+
+  TargetInfo::CallingConvKind
+  getCallingConvKind(bool ClangABICompat4) const override {
+    return CCK_MicrosoftWin64;
+  }
+};
+
 // x86-64 Windows target
 class LLVM_LIBRARY_VISIBILITY WindowsX86_64TargetInfo
     : public WindowsTargetInfo<X86_64TargetInfo> {

clang/lib/Driver/CMakeLists.txt

@@ -78,6 +78,7 @@ add_clang_library(clangDriver
   ToolChains/Solaris.cpp
   ToolChains/SPIRV.cpp
   ToolChains/TCE.cpp
+  ToolChains/UEFI.cpp
   ToolChains/VEToolchain.cpp
   ToolChains/WebAssembly.cpp
   ToolChains/XCore.cpp

clang/lib/Driver/Driver.cpp

@@ -45,6 +45,7 @@
 #include "ToolChains/SPIRV.h"
 #include "ToolChains/Solaris.h"
 #include "ToolChains/TCE.h"
+#include "ToolChains/UEFI.h"
 #include "ToolChains/VEToolchain.h"
 #include "ToolChains/WebAssembly.h"
 #include "ToolChains/XCore.h"
@@ -6416,6 +6417,9 @@ const ToolChain &Driver::getToolChain(const ArgList &Args,
     case llvm::Triple::Mesa3D:
       TC = std::make_unique<toolchains::AMDGPUToolChain>(*this, Target, Args);
       break;
+    case llvm::Triple::UEFI:
+      TC = std::make_unique<toolchains::UEFI>(*this, Target, Args);
+      break;
     case llvm::Triple::Win32:
       switch (Target.getEnvironment()) {
       default:

clang/lib/Driver/ToolChains/UEFI.cpp

@@ -0,0 +1,88 @@
+//===--- UEFI.cpp - UEFI ToolChain Implementations -----------------------===//
+//
+// 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) {}
+
+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);
+
+  AddLinkerInputs(TC, Inputs, Args, CmdArgs, JA);
+
+  // 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 == "lld")
+    Linker = "lld-link";
+
+  auto LinkerPath = TC.GetProgramPath(Linker.str().c_str());
+  auto LinkCmd = std::make_unique<Command>(
+      JA, *this, ResponseFileSupport::AtFileUTF16(),
+      Args.MakeArgString(LinkerPath), CmdArgs, Inputs, Output);
+  C.addCommand(std::move(LinkCmd));
+}

clang/lib/Driver/ToolChains/UEFI.h

@@ -0,0 +1,59 @@
+//===--- 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_UEFI_H
+#define LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_UEFI_H
+
+#include "clang/Driver/Tool.h"
+#include "clang/Driver/ToolChain.h"
+
+namespace clang::driver {
+namespace tools {
+namespace uefi {
+class LLVM_LIBRARY_VISIBILITY Linker : public Tool {
+public:
+  Linker(const ToolChain &TC) : Tool("uefi::Linker", "lld-link", 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 uefi
+} // end namespace tools
+
+namespace toolchains {
+
+class LLVM_LIBRARY_VISIBILITY UEFI : public ToolChain {
+public:
+  UEFI(const Driver &D, const llvm::Triple &Triple,
+       const llvm::opt::ArgList &Args);
+
+protected:
+  Tool *buildLinker() const override;
+
+public:
+  bool HasNativeLLVMSupport() const override { return true; }
+  UnwindTableLevel
+  getDefaultUnwindTableLevel(const llvm::opt::ArgList &Args) const override {
+    return UnwindTableLevel::Asynchronous;
+  }
+  bool isPICDefault() const override { return true; }
+  bool isPIEDefault(const llvm::opt::ArgList &Args) const override {
+    return false;
+  }
+  bool isPICDefaultForced() const override { return true; }
+};
+
+} // namespace toolchains
+} // namespace clang::driver
+
+#endif // LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_UEFI_H

clang/test/CodeGen/X86/uefi-data-layout.c

@@ -0,0 +1,3 @@
+// RUN: %clang -target x86_64-unknown-uefi -S -emit-llvm -o - %s | \
+// RUN:     FileCheck --check-prefix=X86_64_UEFI %s
+// X86_64_UEFI: target datalayout = "e-m:w-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"

clang/test/Driver/uefi-constructed-args.c

@@ -0,0 +1,13 @@
+// RUN: %clang_cl -### %s --target=x86_64-unknown-uefi \
+// RUN:     --sysroot=%S/platform -fuse-ld=lld -g 2>&1 \
+// RUN:     | FileCheck -check-prefixes=CHECK %s
+// CHECK: "-cc1"
+// CHECK-SAME: "-triple" "x86_64-unknown-uefi"
+// CHECK-SAME: "-mrelocation-model" "pic" "-pic-level" "2"
+// CHECK-SAME: "-mframe-pointer=all"
+// CHECK-NEXT: "-nologo"
+// CHECK-SAME: "-subsystem:efi_application"
+// CHECK-SAME: "-entry:EfiMain"
+// CHECK-SAME: "-tsaware:no"
+// CHECK-SAME: "-dll"
+// CHECK-SAME: "-debug"

clang/unittests/Driver/ToolChainTest.cpp

@@ -14,6 +14,7 @@
 #include "clang/Basic/DiagnosticIDs.h"
 #include "clang/Basic/DiagnosticOptions.h"
 #include "clang/Basic/LLVM.h"
+#include "clang/Basic/TargetInfo.h"
 #include "clang/Basic/TargetOptions.h"
 #include "clang/Driver/Compilation.h"
 #include "clang/Driver/Driver.h"
@@ -574,6 +575,26 @@ TEST(CompilerInvocation, SplitSwarfSingleCrash) {
   EXPECT_TRUE(CI); // no-crash
 }
 
+TEST(ToolChainTest, UEFICallingConventionTest) {
+  clang::CompilerInstance compiler;
+  compiler.createDiagnostics();
+
+  std::string TrStr = "x86_64-unknown-uefi";
+  llvm::Triple Tr(TrStr);
+  Tr.setOS(llvm::Triple::OSType::UEFI);
+  Tr.setVendor(llvm::Triple::VendorType::UnknownVendor);
+  Tr.setEnvironment(llvm::Triple::EnvironmentType::UnknownEnvironment);
+  Tr.setArch(llvm::Triple::ArchType::x86_64);
+
+  compiler.getTargetOpts().Triple = Tr.getTriple();
+  compiler.setTarget(clang::TargetInfo::CreateTargetInfo(
+      compiler.getDiagnostics(),
+      std::make_shared<clang::TargetOptions>(compiler.getTargetOpts())));
+
+  EXPECT_EQ(compiler.getTarget().getCallingConvKind(true),
+            TargetInfo::CallingConvKind::CCK_MicrosoftWin64);
+}
+
 TEST(GetDriverMode, PrefersLastDriverMode) {
   static constexpr const char *Args[] = {"clang-cl", "--driver-mode=foo",
                                          "--driver-mode=bar", "foo.cpp"};