[clang] Move `ApplyHeaderSearchOptions` from Frontend to Lex

[jansvoboda11]

Summary

In D116750, the clangFrontend library was added as a dependency of LexTests in order to make clang::ApplyHeaderSearchOptions() available. This increased the number of TUs the test depends on.

This patch moves the function into clangLex and removes dependency of LexTests on clangFrontend.

[jansvoboda11]

Re-run clang-format

[thakis]

That was easy :) Thanks!

clang/include/clang/Frontend/Utils.h

 #include "llvm/Support/VirtualFileSystem.h"
 #include <cstdint>
 #include <memory>
 #include <string>
 #include <system_error>
 #include <utility>
 #include <vector>
 
-namespace llvm {
-
-class Triple;
-
-} // namespace llvm
-
 namespace clang {
 
 class ASTReader;
 class CompilerInstance;
 class CompilerInvocation;
 class DiagnosticsEngine;
 class ExternalSemaSource;
 class FrontendOptions;
-class HeaderSearch;
-class HeaderSearchOptions;
-class LangOptions;
 class PCHContainerReader;
 class Preprocessor;
 class PreprocessorOptions;
 class PreprocessorOutputOptions;
 
-/// Apply the header search options to get given HeaderSearch object.
-void ApplyHeaderSearchOptions(HeaderSearch &HS,
-                              const HeaderSearchOptions &HSOpts,
-                              const LangOptions &Lang,
-                              const llvm::Triple &triple);
-
 /// InitializePreprocessor - Initialize the preprocessor getting it and the
 /// environment ready to process a single file.
 void InitializePreprocessor(Preprocessor &PP, const PreprocessorOptions &PPOpts,
                             const PCHContainerReader &PCHContainerRdr,
                             const FrontendOptions &FEOpts);
 
 /// DoPrintPreprocessedInput - Implement -E mode.
 void DoPrintPreprocessedInput(Preprocessor &PP, raw_ostream *OS,

clang/include/clang/Lex/HeaderSearch.h

 #include "llvm/Support/Allocator.h"
 #include <cassert>
 #include <cstddef>
 #include <memory>
 #include <string>
 #include <utility>
 #include <vector>
 
+namespace llvm {
+
+class Triple;
+
+} // namespace llvm
+
 namespace clang {
 
 class DiagnosticsEngine;
 class DirectoryEntry;
 class ExternalPreprocessorSource;
 class FileEntry;
 class FileManager;
 class HeaderSearchOptions;
private:
   /// \param IsFramework Whether this is a framework directory.
   ///
   /// \returns The result of attempting to load the module map file from the
   /// named directory.
   LoadModuleMapResult loadModuleMapFile(const DirectoryEntry *Dir,
                                         bool IsSystem, bool IsFramework);
 };
 
+/// Apply the header search options to get given HeaderSearch object.
+void ApplyHeaderSearchOptions(HeaderSearch &HS,
+                              const HeaderSearchOptions &HSOpts,
+                              const LangOptions &Lang,
+                              const llvm::Triple &triple);
+
 } // namespace clang
 
 #endif // LLVM_CLANG_LEX_HEADERSEARCH_H

clang/lib/Frontend/CMakeLists.txt

add_clang_library(clangFrontend
   CreateInvocationFromCommandLine.cpp
   DependencyFile.cpp
   DependencyGraph.cpp
   DiagnosticRenderer.cpp
   FrontendAction.cpp
   FrontendActions.cpp
   FrontendOptions.cpp
   HeaderIncludeGen.cpp
-  InitHeaderSearch.cpp
   InitPreprocessor.cpp
   LayoutOverrideSource.cpp
   LogDiagnosticPrinter.cpp
   ModuleDependencyCollector.cpp
   MultiplexConsumer.cpp
   PrecompiledPreamble.cpp
   PrintPreprocessedOutput.cpp
   SerializedDiagnosticPrinter.cpp

clang/lib/Lex/CMakeLists.txt

 # TODO: Add -maltivec when ARCH is PowerPC.
 
 set(LLVM_LINK_COMPONENTS support)
 
 add_clang_library(clangLex
   DependencyDirectivesSourceMinimizer.cpp
   HeaderMap.cpp
   HeaderSearch.cpp
+  InitHeaderSearch.cpp
   Lexer.cpp
   LiteralSupport.cpp
   MacroArgs.cpp
   MacroInfo.cpp
   ModuleMap.cpp
   PPCaching.cpp
   PPCallbacks.cpp
   PPConditionalDirectiveRecord.cpp

clang/lib/Lex/InitHeaderSearch.cpp

 //===--- InitHeaderSearch.cpp - Initialize header search paths ------------===//
 //
 // 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
 //
 //===----------------------------------------------------------------------===//
 //
 // This file implements the InitHeaderSearch class.
 //
 //===----------------------------------------------------------------------===//
 
+#include "clang/Basic/DiagnosticFrontend.h"
 #include "clang/Basic/FileManager.h"
 #include "clang/Basic/LangOptions.h"
 #include "clang/Config/config.h" // C_INCLUDE_DIRS
-#include "clang/Frontend/FrontendDiagnostic.h"
-#include "clang/Frontend/Utils.h"
 #include "clang/Lex/HeaderMap.h"
 #include "clang/Lex/HeaderSearch.h"
 #include "clang/Lex/HeaderSearchOptions.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/Triple.h"

clang/unittests/Lex/CMakeLists.txt

add_clang_unittest(LexTests
   PPCallbacksTest.cpp
   PPConditionalDirectiveRecordTest.cpp
   )
 
 clang_target_link_libraries(LexTests
   PRIVATE
   clangAST
   clangBasic
-  clangFrontend
   clangLex
   clangParse
   clangSema
   )

clang/unittests/Lex/HeaderSearchTest.cpp

 #include "HeaderMapTestUtils.h"
 #include "clang/Basic/Diagnostic.h"
 #include "clang/Basic/DiagnosticOptions.h"
 #include "clang/Basic/FileManager.h"
 #include "clang/Basic/LangOptions.h"
 #include "clang/Basic/SourceManager.h"
 #include "clang/Basic/TargetInfo.h"
 #include "clang/Basic/TargetOptions.h"
-#include "clang/Frontend/Utils.h"
-#include "clang/Lex/HeaderSearch.h"
 #include "clang/Lex/HeaderSearchOptions.h"
 #include "clang/Serialization/InMemoryModuleCache.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "gtest/gtest.h"
 
 namespace clang {
 namespace {