Prune include of DataLayout.h from include/clang/Basic/TargetInfo.h. NFC

[bjope]

Summary

Use a forward declaration of DataLayout instead of including
DataLayout.h in clangs TargetInfo.h. This reduces include
dependencies toward DataLayout.h (and other headers such as
DerivedTypes.h, Type.h that is included by DataLayout.h).

Needed to move implemantation of TargetInfo::resetDataLayout
from TargetInfo.h to TargetInfo.cpp.

[rnk]

lgtm

It's interesting that Basic depends on IR at all.

clang/include/clang/Basic/TargetInfo.h

 #ifndef LLVM_CLANG_BASIC_TARGETINFO_H
 #define LLVM_CLANG_BASIC_TARGETINFO_H
 
 #include "clang/Basic/AddressSpaces.h"
 #include "clang/Basic/LLVM.h"
 #include "clang/Basic/Specifiers.h"
 #include "clang/Basic/TargetCXXABI.h"
 #include "clang/Basic/TargetOptions.h"
+#include "llvm/ADT/APFloat.h"
 #include "llvm/ADT/APInt.h"
+#include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/IntrusiveRefCntPtr.h"
 #include "llvm/ADT/Optional.h"
 #include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Triple.h"
-#include "llvm/IR/DataLayout.h"
 #include "llvm/Support/DataTypes.h"
 #include "llvm/Support/VersionTuple.h"
 #include <cassert>
 #include <string>
 #include <vector>
 
 namespace llvm {
 struct fltSemantics;
+class DataLayout;
 }
 
 namespace clang {
 class DiagnosticsEngine;
 class LangOptions;
 class CodeGenOptions;
 class MacroBuilder;
 class QualType;
protected:
 
   unsigned IsRenderScriptTarget : 1;
 
   unsigned HasAArch64SVETypes : 1;
 
   // TargetInfo Constructor.  Default initializes all fields.
   TargetInfo(const llvm::Triple &T);
 
-  void resetDataLayout(StringRef DL) {
-    DataLayout.reset(new llvm::DataLayout(DL));
-  }
+  void resetDataLayout(StringRef DL);
 
 public:
   /// Construct a target for the given options.
   ///
   /// \param Opts - The options to use to initialize the target. The target may
   /// modify the options to canonicalize the target feature information to match
   /// what the backend expects.
   static TargetInfo *

clang/lib/Basic/TargetInfo.cpp

 
 #include "clang/Basic/TargetInfo.h"
 #include "clang/Basic/AddressSpaces.h"
 #include "clang/Basic/CharInfo.h"
 #include "clang/Basic/Diagnostic.h"
 #include "clang/Basic/LangOptions.h"
 #include "llvm/ADT/APFloat.h"
 #include "llvm/ADT/STLExtras.h"
+#include "llvm/IR/DataLayout.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/TargetParser.h"
 #include <cstdlib>
 using namespace clang;
 
 static const LangASMap DefaultAddrSpaceMap = {0};
 
 // TargetInfo Constructor.
TargetInfo::TargetInfo(const llvm::Triple &T) : TargetOpts(), Triple(T) {
   // Default to an unknown platform name.
   PlatformName = "unknown";
   PlatformMinVersion = VersionTuple();
 }
 
 // Out of line virtual dtor for TargetInfo.
 TargetInfo::~TargetInfo() {}
 
+void TargetInfo::resetDataLayout(StringRef DL) {
+  DataLayout.reset(new llvm::DataLayout(DL));
+}
+
 bool
 TargetInfo::checkCFProtectionBranchSupported(DiagnosticsEngine &Diags) const {
   Diags.Report(diag::err_opt_not_valid_on_target) << "cf-protection=branch";
   return false;
 }
 
 bool
 TargetInfo::checkCFProtectionReturnSupported(DiagnosticsEngine &Diags) const {

clang/lib/Basic/Targets/AMDGPU.cpp

 
 #include "AMDGPU.h"
 #include "clang/Basic/Builtins.h"
 #include "clang/Basic/CodeGenOptions.h"
 #include "clang/Basic/LangOptions.h"
 #include "clang/Basic/MacroBuilder.h"
 #include "clang/Basic/TargetBuiltins.h"
 #include "llvm/ADT/StringSwitch.h"
+#include "llvm/IR/DataLayout.h"
 
 using namespace clang;
 using namespace clang::targets;
 
 namespace clang {
 namespace targets {
 
 // If you edit the description strings, make sure you update

clang/lib/Frontend/InitPreprocessor.cpp

 #include "clang/Frontend/FrontendDiagnostic.h"
 #include "clang/Frontend/FrontendOptions.h"
 #include "clang/Frontend/Utils.h"
 #include "clang/Lex/HeaderSearch.h"
 #include "clang/Lex/Preprocessor.h"
 #include "clang/Lex/PreprocessorOptions.h"
 #include "clang/Serialization/ASTReader.h"
 #include "llvm/ADT/APFloat.h"
+#include "llvm/IR/DataLayout.h"
 using namespace clang;
 
 static bool MacroBodyEndsInBackslash(StringRef MacroBody) {
   while (!MacroBody.empty() && isWhitespace(MacroBody.back()))
     MacroBody = MacroBody.drop_back();
   return !MacroBody.empty() && MacroBody.back() == '\\';
 }
 

clang/unittests/AST/DeclTest.cpp

 //===----------------------------------------------------------------------===//
 
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/Mangle.h"
 #include "clang/ASTMatchers/ASTMatchFinder.h"
 #include "clang/Basic/LLVM.h"
 #include "clang/Tooling/Tooling.h"
 #include "gtest/gtest.h"
+#include "llvm/IR/DataLayout.h"
 
 using namespace clang::ast_matchers;
 using namespace clang::tooling;
 using namespace clang;
 
 TEST(Decl, CleansUpAPValues) {
   MatchFinder Finder;
   std::unique_ptr<FrontendActionFactory> Factory(