[llvm] Cleanup header dependencies in ADT and Support

The cleanup was manual, but assisted by "include-what-you-use". It consists in

1. Removing unused forward declaration. No impact expected.
2. Removing unused headers in .cpp files. No impact expected.
3. Removing unused headers in .h files. This removes implicit dependencies and
   is generally considered a good thing, but this may break downstream builds.
   I've updated llvm, clang, lld, lldb and mlir deps, and included a list of the
   modification in the second part of the commit.
4. Replacing header inclusion by forward declaration. This has the same impact
   as 3.

Notable changes:

- llvm/Support/TargetParser.h no longer includes llvm/Support/AArch64TargetParser.h nor llvm/Support/ARMTargetParser.h
- llvm/Support/TypeSize.h no longer includes llvm/Support/WithColor.h
- llvm/Support/YAMLTraits.h no longer includes llvm/Support/Regex.h
- llvm/ADT/SmallVector.h no longer includes llvm/Support/MemAlloc.h nor llvm/Support/ErrorHandling.h

You may need to add some of these headers in your compilation units, if needs be.

As an hint to the impact of the cleanup, running

clang++ -E  -Iinclude -I../llvm/include ../llvm/lib/Support/*.cpp -std=c++14 -fno-rtti -fno-exceptions | wc -l

before: 8000919 lines
after:  7917500 lines

Reduced dependencies also helps incremental rebuilds and is more ccache
friendly, something not shown by the above metric :-)

Discourse thread on the topic: https://llvm.discourse.group/t/include-what-you-use-include-cleanup/5831

Author: serge-sans-paille

clang/lib/Basic/Targets/AArch64.h

@@ -15,6 +15,7 @@
 
 #include "OSTargets.h"
 #include "clang/Basic/TargetBuiltins.h"
+#include "llvm/Support/AArch64TargetParser.h"
 #include "llvm/Support/TargetParser.h"
 
 namespace clang {

clang/lib/Basic/Targets/ARM.h

@@ -18,6 +18,7 @@
 #include "clang/Basic/TargetOptions.h"
 #include "llvm/ADT/Triple.h"
 #include "llvm/Support/Compiler.h"
+#include "llvm/Support/ARMTargetParser.h"
 #include "llvm/Support/TargetParser.h"
 
 namespace clang {

clang/lib/Driver/SanitizerArgs.cpp

@@ -16,6 +16,7 @@
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/SpecialCaseList.h"
+#include "llvm/Support/AArch64TargetParser.h"
 #include "llvm/Support/TargetParser.h"
 #include "llvm/Support/VirtualFileSystem.h"
 #include "llvm/Transforms/Instrumentation/AddressSanitizerOptions.h"

clang/lib/Driver/ToolChains/Arch/AArch64.cpp

@@ -11,6 +11,7 @@
 #include "clang/Driver/DriverDiagnostic.h"
 #include "clang/Driver/Options.h"
 #include "llvm/Option/ArgList.h"
+#include "llvm/Support/AArch64TargetParser.h"
 #include "llvm/Support/TargetParser.h"
 #include "llvm/Support/Host.h"
 

clang/lib/Driver/ToolChains/Arch/ARM.cpp

@@ -12,6 +12,7 @@
 #include "clang/Driver/Options.h"
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/Option/ArgList.h"
+#include "llvm/Support/ARMTargetParser.h"
 #include "llvm/Support/TargetParser.h"
 #include "llvm/Support/Host.h"
 

clang/lib/Driver/ToolChains/Arch/ARM.h

@@ -13,6 +13,7 @@
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Triple.h"
 #include "llvm/Option/Option.h"
+#include "llvm/Support/ARMTargetParser.h"
 #include "llvm/Support/TargetParser.h"
 #include <string>
 #include <vector>

clang/tools/libclang/BuildSystem.cpp

@@ -16,6 +16,7 @@
 #include "llvm/Support/CBindingWrapping.h"
 #include "llvm/Support/Chrono.h"
 #include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/MemAlloc.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/VirtualFileSystem.h"
 #include "llvm/Support/raw_ostream.h"

lldb/source/Host/common/Socket.cpp

@@ -18,6 +18,7 @@
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/Support/Errno.h"
 #include "llvm/Support/Error.h"
+#include "llvm/Support/Regex.h"
 #include "llvm/Support/WindowsError.h"
 
 #if LLDB_ENABLE_POSIX

llvm/include/llvm/ADT/Optional.h

@@ -21,7 +21,6 @@
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/type_traits.h"
 #include <cassert>
-#include <memory>
 #include <new>
 #include <utility>
 

llvm/include/llvm/ADT/SmallVector.h

@@ -15,8 +15,6 @@
 
 #include "llvm/ADT/iterator_range.h"
 #include "llvm/Support/Compiler.h"
-#include "llvm/Support/ErrorHandling.h"
-#include "llvm/Support/MemAlloc.h"
 #include "llvm/Support/type_traits.h"
 #include <algorithm>
 #include <cassert>

llvm/include/llvm/MC/MCStreamer.h

@@ -27,6 +27,7 @@
 #include "llvm/Support/Error.h"
 #include "llvm/Support/MD5.h"
 #include "llvm/Support/SMLoc.h"
+#include "llvm/Support/ARMTargetParser.h"
 #include "llvm/Support/TargetParser.h"
 #include "llvm/Support/VersionTuple.h"
 #include <cassert>

llvm/include/llvm/Object/ELFObjectFile.h

@@ -34,6 +34,7 @@
 #include "llvm/Support/Error.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/ScopedPrinter.h"
 #include <cassert>
 #include <cstdint>
 #include <system_error>

llvm/include/llvm/Support/AArch64TargetParser.h

@@ -14,7 +14,6 @@
 #ifndef LLVM_SUPPORT_AARCH64TARGETPARSER_H
 #define LLVM_SUPPORT_AARCH64TARGETPARSER_H
 
-#include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/ARMTargetParser.h"
 #include <vector>

llvm/include/llvm/Support/ARMAttributeParser.h

@@ -11,14 +11,13 @@
 
 #include "ARMBuildAttributes.h"
 #include "ELFAttributeParser.h"
-#include "ScopedPrinter.h"
-#include "llvm/ADT/ArrayRef.h"
-#include "llvm/Support/DataExtractor.h"
-#include "llvm/Support/Endian.h"
+#include "llvm/ADT/StringRef.h"
 #include "llvm/Support/Error.h"
 
 namespace llvm {
 
+class ScopedPrinter;
+
 class ARMAttributeParser : public ELFAttributeParser {
   struct DisplayHandler {
     ARMBuildAttrs::AttrType attribute;

llvm/include/llvm/Support/Allocator.h

@@ -22,16 +22,12 @@
 #include "llvm/Support/Alignment.h"
 #include "llvm/Support/AllocatorBase.h"
 #include "llvm/Support/Compiler.h"
-#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/MathExtras.h"
-#include "llvm/Support/MemAlloc.h"
 #include <algorithm>
 #include <cassert>
 #include <cstddef>
 #include <cstdint>
-#include <cstdlib>
 #include <iterator>
-#include <type_traits>
 #include <utility>
 
 namespace llvm {

llvm/include/llvm/Support/BinaryStreamReader.h

@@ -10,15 +10,13 @@
 #define LLVM_SUPPORT_BINARYSTREAMREADER_H
 
 #include "llvm/ADT/ArrayRef.h"
-#include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/Alignment.h"
 #include "llvm/Support/BinaryStreamArray.h"
 #include "llvm/Support/BinaryStreamRef.h"
 #include "llvm/Support/ConvertUTF.h"
 #include "llvm/Support/Endian.h"
 #include "llvm/Support/Error.h"
-#include "llvm/Support/type_traits.h"
 #include <type_traits>
 
 namespace llvm {

llvm/include/llvm/Support/BinaryStreamRef.h

@@ -14,7 +14,6 @@
 #include "llvm/Support/BinaryStream.h"
 #include "llvm/Support/BinaryStreamError.h"
 #include "llvm/Support/Error.h"
-#include <algorithm>
 #include <cstdint>
 #include <memory>
 

llvm/include/llvm/Support/BinaryStreamWriter.h

@@ -10,7 +10,6 @@
 #define LLVM_SUPPORT_BINARYSTREAMWRITER_H
 
 #include "llvm/ADT/ArrayRef.h"
-#include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/BinaryStreamArray.h"
 #include "llvm/Support/BinaryStreamError.h"

llvm/include/llvm/Support/BlockFrequency.h

@@ -13,12 +13,11 @@
 #ifndef LLVM_SUPPORT_BLOCKFREQUENCY_H
 #define LLVM_SUPPORT_BLOCKFREQUENCY_H
 
-#include "llvm/Support/BranchProbability.h"
-#include "llvm/Support/DataTypes.h"
+#include <cstdint>
 
 namespace llvm {
 
-class raw_ostream;
+class BranchProbability;
 
 // This class represents Block Frequency as a 64-bit value.
 class BlockFrequency {

llvm/include/llvm/Support/BranchProbability.h

@@ -16,7 +16,6 @@
 #include "llvm/Support/DataTypes.h"
 #include <algorithm>
 #include <cassert>
-#include <climits>
 #include <numeric>
 
 namespace llvm {

llvm/include/llvm/Support/ConvertUTF.h

@@ -91,7 +91,6 @@
 
 #include <cstddef>
 #include <string>
-#include <system_error>
 
 // Wrap everything in namespace llvm so that programs can link with llvm and
 // their own version of the unicode libraries.

llvm/include/llvm/Support/ELFAttributeParser.h

@@ -10,15 +10,16 @@
 #define LLVM_SUPPORT_ELFATTRIBUTEPARSER_H
 
 #include "ELFAttributes.h"
-#include "ScopedPrinter.h"
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/Support/DataExtractor.h"
+#include "llvm/Support/Endian.h"
 #include "llvm/Support/Error.h"
 
 #include <unordered_map>
 
 namespace llvm {
 class StringRef;
+class ScopedPrinter;
 
 class ELFAttributeParser {
   StringRef vendor;

llvm/include/llvm/Support/Error.h

@@ -14,7 +14,6 @@
 #define LLVM_SUPPORT_ERROR_H
 
 #include "llvm-c/Error.h"
-#include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/Twine.h"

llvm/include/llvm/Support/ExtensibleRTTI.h

@@ -62,8 +62,6 @@
 
 namespace llvm {
 
-template <typename ThisT, typename ParentT> class RTTIExtends;
-
 /// Base class for the extensible RTTI hierarchy.
 ///
 /// This class defines virtual methods, dynamicClassID and isA, that enable

llvm/include/llvm/Support/FileCollector.h

@@ -9,7 +9,6 @@
 #ifndef LLVM_SUPPORT_FILECOLLECTOR_H
 #define LLVM_SUPPORT_FILECOLLECTOR_H
 
-#include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringSet.h"
 #include "llvm/Support/VirtualFileSystem.h"

llvm/include/llvm/Support/FileUtilities.h

@@ -15,10 +15,10 @@
 #define LLVM_SUPPORT_FILEUTILITIES_H
 
 #include "llvm/ADT/StringRef.h"
-#include "llvm/Support/Errc.h"
-#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/Error.h"
 #include "llvm/Support/FileSystem.h"
-#include "llvm/Support/Path.h"
+
+#include <system_error>
 
 namespace llvm {
 

llvm/include/llvm/Support/FormatVariadic.h

@@ -29,16 +29,17 @@
 #include "llvm/ADT/Optional.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/FormatCommon.h"
 #include "llvm/Support/FormatProviders.h"
 #include "llvm/Support/FormatVariadicDetails.h"
 #include "llvm/Support/raw_ostream.h"
+#include <array>
 #include <cstddef>
 #include <string>
 #include <tuple>
 #include <utility>
-#include <vector>
 
 namespace llvm {
 

llvm/include/llvm/Support/GraphWriter.h

@@ -28,8 +28,6 @@
 #include "llvm/Support/DOTGraphTraits.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/raw_ostream.h"
-#include <algorithm>
-#include <cstddef>
 #include <iterator>
 #include <string>
 #include <type_traits>

llvm/include/llvm/Support/ItaniumManglingCanonicalizer.h

@@ -14,7 +14,6 @@
 #ifndef LLVM_SUPPORT_ITANIUMMANGLINGCANONICALIZER_H
 #define LLVM_SUPPORT_ITANIUMMANGLINGCANONICALIZER_H
 
-#include <cstddef>
 #include <cstdint>
 
 namespace llvm {

llvm/include/llvm/Support/RISCVISAInfo.h

@@ -9,8 +9,6 @@
 #ifndef LLVM_SUPPORT_RISCVISAINFO_H
 #define LLVM_SUPPORT_RISCVISAINFO_H
 
-#include "llvm/ADT/Optional.h"
-#include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/Error.h"
 

llvm/include/llvm/Support/SymbolRemappingReader.h

@@ -62,10 +62,11 @@
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/ItaniumManglingCanonicalizer.h"
-#include "llvm/Support/MemoryBuffer.h"
 
 namespace llvm {
 
+class MemoryBuffer;
+
 class SymbolRemappingParseError : public ErrorInfo<SymbolRemappingParseError> {
 public:
   SymbolRemappingParseError(StringRef File, int64_t Line, const Twine &Message)

llvm/include/llvm/Support/TargetParser.h

@@ -17,8 +17,6 @@
 // FIXME: vector is used because that's what clang uses for subtarget feature
 // lists, but SmallVector would probably be better
 #include "llvm/ADT/Triple.h"
-#include "llvm/Support/AArch64TargetParser.h"
-#include "llvm/Support/ARMTargetParser.h"
 #include "llvm/Support/RISCVISAInfo.h"
 #include <vector>
 

llvm/include/llvm/Support/TimeProfiler.h

@@ -10,10 +10,11 @@
 #define LLVM_SUPPORT_TIMEPROFILER_H
 
 #include "llvm/Support/Error.h"
-#include "llvm/Support/raw_ostream.h"
 
 namespace llvm {
 
+class raw_pwrite_stream;
+
 struct TimeTraceProfiler;
 TimeTraceProfiler *getTimeTraceProfilerInstance();
 

llvm/include/llvm/Support/Timer.h

@@ -14,12 +14,10 @@
 #include "llvm/Support/DataTypes.h"
 #include <cassert>
 #include <string>
-#include <utility>
 #include <vector>
 
 namespace llvm {
 
-class Timer;
 class TimerGroup;
 class raw_ostream;
 

llvm/include/llvm/Support/TrigramIndex.h

@@ -33,7 +33,6 @@
 #include <vector>
 
 namespace llvm {
-class StringRef;
 
 class TrigramIndex {
  public:

llvm/include/llvm/Support/TypeSize.h

@@ -17,7 +17,7 @@
 
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/Support/MathExtras.h"
-#include "llvm/Support/WithColor.h"
+#include "llvm/Support/raw_ostream.h"
 
 #include <algorithm>
 #include <array>

llvm/include/llvm/Support/YAMLTraits.h

@@ -18,17 +18,13 @@
 #include "llvm/Support/AlignOf.h"
 #include "llvm/Support/Allocator.h"
 #include "llvm/Support/Endian.h"
-#include "llvm/Support/Regex.h"
 #include "llvm/Support/SMLoc.h"
 #include "llvm/Support/SourceMgr.h"
 #include "llvm/Support/VersionTuple.h"
 #include "llvm/Support/YAMLParser.h"
 #include "llvm/Support/raw_ostream.h"
 #include <cassert>
 #include <cctype>
-#include <cstddef>
-#include <cstdint>
-#include <iterator>
 #include <map>
 #include <memory>
 #include <new>

llvm/lib/Debuginfod/Debuginfod.cpp

@@ -21,8 +21,10 @@
 #include "llvm/Debuginfod/HTTPClient.h"
 #include "llvm/Support/CachePruning.h"
 #include "llvm/Support/Caching.h"
+#include "llvm/Support/Errc.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/FileUtilities.h"
+#include "llvm/Support/Path.h"
 #include "llvm/Support/xxhash.h"
 
 namespace llvm {