[clang] [NFC] Minimize header includes (PR #66339)

[Bill Wendling via cfe-commits]

https://github.com/bwendling created https://github.com/llvm/llvm-project/pull/66339:

Minimize the headers included in header files to reduce the number of files that need recompiled after a change.

>From fafc158270aa454253d885111c297ab0aaaca7dc Mon Sep 17 00:00:00 2001
From: Bill Wendling <morbo at google.com>
Date: Thu, 14 Sep 2023 01:21:51 -0700
Subject: [PATCH] [NFC] Minimize header includes

Minimize the headers included in header files to reduce the number of
files that need recompiled after a change.
---
 .../include/clang/Basic/AttrSubjectMatchRules.h  |  4 +++-
 clang/include/clang/Basic/AttributeCommonInfo.h  |  4 +++-
 clang/include/clang/Basic/Attributes.h           |  4 ++--
 clang/lib/Basic/Attributes.cpp                   | 16 +++++++++++++++-
 clang/lib/Basic/IdentifierTable.cpp              |  4 +---
 clang/lib/Parse/ParseStmt.cpp                    |  1 +
 6 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/clang/include/clang/Basic/AttrSubjectMatchRules.h b/clang/include/clang/Basic/AttrSubjectMatchRules.h
index e3dcb943e59d424..bec8122ea930a6a 100644
--- a/clang/include/clang/Basic/AttrSubjectMatchRules.h
+++ b/clang/include/clang/Basic/AttrSubjectMatchRules.h
@@ -9,10 +9,12 @@
 #ifndef LLVM_CLANG_BASIC_ATTRSUBJECTMATCHRULES_H
 #define LLVM_CLANG_BASIC_ATTRSUBJECTMATCHRULES_H
 
-#include "clang/Basic/SourceLocation.h"
 #include "llvm/ADT/DenseMap.h"
 
 namespace clang {
+
+class SourceRange;
+
 namespace attr {
 
 /// A list of all the recognized kinds of attributes.
diff --git a/clang/include/clang/Basic/AttributeCommonInfo.h b/clang/include/clang/Basic/AttributeCommonInfo.h
index e57adc4bf5b99a2..7dc05418498d0ae 100644
--- a/clang/include/clang/Basic/AttributeCommonInfo.h
+++ b/clang/include/clang/Basic/AttributeCommonInfo.h
@@ -13,12 +13,14 @@
 
 #ifndef LLVM_CLANG_BASIC_ATTRIBUTECOMMONINFO_H
 #define LLVM_CLANG_BASIC_ATTRIBUTECOMMONINFO_H
+
 #include "clang/Basic/SourceLocation.h"
 #include "clang/Basic/TokenKinds.h"
 
 namespace clang {
-class IdentifierInfo;
+
 class ASTRecordWriter;
+class IdentifierInfo;
 
 class AttributeCommonInfo {
 public:
diff --git a/clang/include/clang/Basic/Attributes.h b/clang/include/clang/Basic/Attributes.h
index 3fc5fbacdb2cbd6..61666a6f4d9ac4a 100644
--- a/clang/include/clang/Basic/Attributes.h
+++ b/clang/include/clang/Basic/Attributes.h
@@ -10,12 +10,12 @@
 #define LLVM_CLANG_BASIC_ATTRIBUTES_H
 
 #include "clang/Basic/AttributeCommonInfo.h"
-#include "clang/Basic/LangOptions.h"
-#include "clang/Basic/TargetInfo.h"
 
 namespace clang {
 
 class IdentifierInfo;
+class LangOptions;
+class TargetInfo;
 
 /// Return the version number associated with the attribute if we
 /// recognize and implement the attribute specified by the given information.
diff --git a/clang/lib/Basic/Attributes.cpp b/clang/lib/Basic/Attributes.cpp
index 1308e2d72f25f5b..bb495216ca93ca5 100644
--- a/clang/lib/Basic/Attributes.cpp
+++ b/clang/lib/Basic/Attributes.cpp
@@ -1,8 +1,22 @@
+//===--- Attributes.cpp ---------------------------------------------------===//
+//
+// 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 AttributeCommonInfo interface.
+//
+//===----------------------------------------------------------------------===//
+
 #include "clang/Basic/Attributes.h"
 #include "clang/Basic/AttrSubjectMatchRules.h"
-#include "clang/Basic/AttributeCommonInfo.h"
 #include "clang/Basic/IdentifierTable.h"
+#include "clang/Basic/LangOptions.h"
 #include "clang/Basic/ParsedAttrInfo.h"
+#include "clang/Basic/TargetInfo.h"
+
 using namespace clang;
 
 static int hasAttributeImpl(AttributeCommonInfo::Syntax Syntax, StringRef Name,
diff --git a/clang/lib/Basic/IdentifierTable.cpp b/clang/lib/Basic/IdentifierTable.cpp
index afb30268f2973ce..e5599d545541085 100644
--- a/clang/lib/Basic/IdentifierTable.cpp
+++ b/clang/lib/Basic/IdentifierTable.cpp
@@ -25,7 +25,6 @@
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/Allocator.h"
-#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/raw_ostream.h"
 #include <cassert>
 #include <cstdio>
@@ -52,8 +51,7 @@ namespace {
 
 /// A simple identifier lookup iterator that represents an
 /// empty sequence of identifiers.
-class EmptyLookupIterator : public IdentifierIterator
-{
+class EmptyLookupIterator : public IdentifierIterator {
 public:
   StringRef Next() override { return StringRef(); }
 };
diff --git a/clang/lib/Parse/ParseStmt.cpp b/clang/lib/Parse/ParseStmt.cpp
index fb883c08a745cfa..2531147c23196ae 100644
--- a/clang/lib/Parse/ParseStmt.cpp
+++ b/clang/lib/Parse/ParseStmt.cpp
@@ -14,6 +14,7 @@
 #include "clang/AST/PrettyDeclStackTrace.h"
 #include "clang/Basic/Attributes.h"
 #include "clang/Basic/PrettyStackTrace.h"
+#include "clang/Basic/TargetInfo.h"
 #include "clang/Basic/TokenKinds.h"
 #include "clang/Parse/LoopHint.h"
 #include "clang/Parse/Parser.h"