[clang] Move `ApplyHeaderSearchOptions` from Frontend to Lex

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`.

Reviewed By: thakis

Differential Revision: https://reviews.llvm.org/D117024

clang/include/clang/Frontend/Utils.h

@@ -32,12 +32,6 @@
 #include <utility>
 #include <vector>
 
-namespace llvm {
-
-class Triple;
-
-} // namespace llvm
-
 namespace clang {
 
 class ASTReader;
@@ -46,20 +40,11 @@ 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,

clang/include/clang/Lex/HeaderSearch.h

@@ -34,6 +34,12 @@
 #include <utility>
 #include <vector>
 
+namespace llvm {
+
+class Triple;
+
+} // namespace llvm
+
 namespace clang {
 
 class DiagnosticsEngine;
@@ -853,6 +859,12 @@ private:
                                         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

@@ -24,7 +24,6 @@ add_clang_library(clangFrontend
   FrontendActions.cpp
   FrontendOptions.cpp
   HeaderIncludeGen.cpp
-  InitHeaderSearch.cpp
   InitPreprocessor.cpp
   LayoutOverrideSource.cpp
   LogDiagnosticPrinter.cpp

clang/lib/Lex/CMakeLists.txt

@@ -6,6 +6,7 @@ add_clang_library(clangLex
   DependencyDirectivesSourceMinimizer.cpp
   HeaderMap.cpp
   HeaderSearch.cpp
+  InitHeaderSearch.cpp
   Lexer.cpp
   LiteralSupport.cpp
   MacroArgs.cpp

clang/lib/Lex/InitHeaderSearch.cpp

@@ -10,11 +10,10 @@
 //
 //===----------------------------------------------------------------------===//
 
+#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"

clang/unittests/Lex/CMakeLists.txt

@@ -15,7 +15,6 @@ clang_target_link_libraries(LexTests
   PRIVATE
   clangAST
   clangBasic
-  clangFrontend
   clangLex
   clangParse
   clangSema

clang/unittests/Lex/HeaderSearchTest.cpp

@@ -15,8 +15,6 @@
 #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"