Include Region.h in OperationSupport.h instead of forward declaring it (NFC)

[mehdi_amini]

Summary

This fixes the build on gcc5 toolchain where sizeof is required for
types used in SmallVector now.
This is a consequence of using std::is_trivially_copy_constructible
instead of the LLVM variant: https://reviews.llvm.org/D92543

[miyuki]

Hi. This also affects llvm/lib/CodeGen/AsmPrinter/DebugLocStream.cpp and llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp (forward declarations of llvm::DwarfCompileUnit and llvm::DwarfTypeUnit).

[miyuki]

And another group of errors looks related as well:

[41/4081] Building CXX object lib/CodeGen/GlobalISel/CMakeFiles/LLVMGlobalISel.dir/RegBankSelect.cpp.o
FAILED: CCACHE_DIR=/work/ccache/llvm CCACHE_MAXSIZE=20G CCACHE_CPP2=yes /usr/bin/ccache /arm/devsys-tools/collections/gcc/7.3.0/1/linux_3.2-ubuntu_12.04-x86_64/gcc-4.6.3-SYSTEM/bin/g++  -DGTEST_HAS_RTTI=0 -D_DEBUG -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -Ilib/CodeGen/GlobalISel -I/work/repos/llvm/src/llvm/lib/CodeGen/GlobalISel -Iinclude -I/work/repos/llvm/src/llvm/include -fPIC -fvisibility-inlines-hidden -Werror=date-time -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wno-missing-field-initializers -pedantic -Wno-long-long -Wimplicit-fallthrough -Wno-maybe-uninitialized -Wno-noexcept-type -Wdelete-non-virtual-dtor -Wno-comment -fdiagnostics-color -g -fPIC    -fno-exceptions -fno-rtti -std=c++14 -MD -MT lib/CodeGen/GlobalISel/CMakeFiles/LLVMGlobalISel.dir/RegBankSelect.cpp.o -MF lib/CodeGen/GlobalISel/CMakeFiles/LLVMGlobalISel.dir/RegBankSelect.cpp.o.d -o lib/CodeGen/GlobalISel/CMakeFiles/LLVMGlobalISel.dir/RegBankSelect.cpp.o -c /work/repos/llvm/src/llvm/lib/CodeGen/GlobalISel/RegBankSelect.cpp
In file included from /arm/devsys-tools/collections/gcc/7.3.0/1/linux_3.2-ubuntu_12.04-x86_64/gcc-4.6.3-SYSTEM/include/c++/7.3.0/bits/char_traits.h:39:0,
                 from /arm/devsys-tools/collections/gcc/7.3.0/1/linux_3.2-ubuntu_12.04-x86_64/gcc-4.6.3-SYSTEM/include/c++/7.3.0/string:40,
                 from /work/repos/llvm/src/llvm/include/llvm/Support/ErrorHandling.h:18,
                 from /work/repos/llvm/src/llvm/include/llvm/ADT/SmallVector.h:18,
                 from /work/repos/llvm/src/llvm/include/llvm/CodeGen/GlobalISel/RegBankSelect.h:66,
                 from /work/repos/llvm/src/llvm/lib/CodeGen/GlobalISel/RegBankSelect.cpp:12:
/arm/devsys-tools/collections/gcc/7.3.0/1/linux_3.2-ubuntu_12.04-x86_64/gcc-4.6.3-SYSTEM/include/c++/7.3.0/bits/stl_algobase.h: In instantiation of 'static _OI std::__copy_move<false, false, std::random_access_iterator_tag>::__copy_m(_II, _II, _OI) [with _II = const std::unique_ptr<llvm::RegBankSelect::InsertPoint>*; _OI = std::unique_ptr<llvm::RegBankSelect::InsertPoint>*]':
/arm/devsys-tools/collections/gcc/7.3.0/1/linux_3.2-ubuntu_12.04-x86_64/gcc-4.6.3-SYSTEM/include/c++/7.3.0/bits/stl_algobase.h:386:44:   required from '_OI std::__copy_move_a(_II, _II, _OI) [with bool _IsMove = false; _II = const std::unique_ptr<llvm::RegBankSelect::InsertPoint>*; _OI = std::unique_ptr<llvm::RegBankSelect::InsertPoint>*]'
/arm/devsys-tools/collections/gcc/7.3.0/1/linux_3.2-ubuntu_12.04-x86_64/gcc-4.6.3-SYSTEM/include/c++/7.3.0/bits/stl_algobase.h:422:45:   required from '_OI std::__copy_move_a2(_II, _II, _OI) [with bool _IsMove = false; _II = const std::unique_ptr<llvm::RegBankSelect::InsertPoint>*; _OI = std::unique_ptr<llvm::RegBankSelect::InsertPoint>*]'
/arm/devsys-tools/collections/gcc/7.3.0/1/linux_3.2-ubuntu_12.04-x86_64/gcc-4.6.3-SYSTEM/include/c++/7.3.0/bits/stl_algobase.h:455:8:   required from '_OI std::copy(_II, _II, _OI) [with _II = const std::unique_ptr<llvm::RegBankSelect::InsertPoint>*; _OI = std::unique_ptr<llvm::RegBankSelect::InsertPoint>*]'
/work/repos/llvm/src/llvm/include/llvm/ADT/SmallVector.h:842:25:   required from 'llvm::SmallVectorImpl<T>& llvm::SmallVectorImpl<T>::operator=(const llvm::SmallVectorImpl<T>&) [with T = std::unique_ptr<llvm::RegBankSelect::InsertPoint>]'
/work/repos/llvm/src/llvm/include/llvm/ADT/SmallVector.h:995:36:   required from 'llvm::SmallVector<T, N>::SmallVector(const llvm::SmallVector<T, N>&) [with T = std::unique_ptr<llvm::RegBankSelect::InsertPoint>; unsigned int N = 2]'
/work/repos/llvm/src/llvm/include/llvm/CodeGen/GlobalISel/RegBankSelect.h:313:9:   required from 'struct std::is_trivially_copy_constructible<llvm::RegBankSelect::RepairingPlacement>'
/work/repos/llvm/src/llvm/include/llvm/ADT/SmallVector.h:281:79:   required from 'class llvm::SmallVectorImpl<llvm::RegBankSelect::RepairingPlacement>'
/work/repos/llvm/src/llvm/include/llvm/ADT/SmallVector.h:960:22:   required from 'class llvm::SmallVector<llvm::RegBankSelect::RepairingPlacement, 4>'
/work/repos/llvm/src/llvm/lib/CodeGen/GlobalISel/RegBankSelect.cpp:297:38:   required from here
/arm/devsys-tools/collections/gcc/7.3.0/1/linux_3.2-ubuntu_12.04-x86_64/gcc-4.6.3-SYSTEM/include/c++/7.3.0/bits/stl_algobase.h:324:18: error: use of deleted function 'std::unique_ptr<_Tp, _Dp>& std::unique_ptr<_Tp, _Dp>::operator=(const std::unique_ptr<_Tp, _Dp>&) [with _Tp = llvm::RegBankSelect::InsertPoint; _Dp = std::default_delete<llvm::RegBankSelect::InsertPoint>]'
        *__result = *__first;
        ~~~~~~~~~~^~~~~~~~~~

[384/4081] Building CXX object lib/Analysis/CMakeFiles/LLVMAnalysis.dir/LoopCacheAnalysis.cpp.o
FAILED: CCACHE_DIR=/work/ccache/llvm CCACHE_MAXSIZE=20G CCACHE_CPP2=yes /usr/bin/ccache /arm/devsys-tools/collections/gcc/7.3.0/1/linux_3.2-ubuntu_12.04-x86_64/gcc-4.6.3-SYSTEM/bin/g++  -DGTEST_HAS_RTTI=0 -D_DEBUG -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -Ilib/Analysis -I/work/repos/llvm/src/llvm/lib/Analysis -Iinclude -I/work/repos/llvm/src/llvm/include -fPIC -fvisibility-inlines-hidden -Werror=date-time -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wno-missing-field-initializers -pedantic -Wno-long-long -Wimplicit-fallthrough -Wno-maybe-uninitialized -Wno-noexcept-type -Wdelete-non-virtual-dtor -Wno-comment -fdiagnostics-color -g -fPIC    -fno-exceptions -fno-rtti -std=c++14 -MD -MT lib/Analysis/CMakeFiles/LLVMAnalysis.dir/LoopCacheAnalysis.cpp.o -MF lib/Analysis/CMakeFiles/LLVMAnalysis.dir/LoopCacheAnalysis.cpp.o.d -o lib/Analysis/CMakeFiles/LLVMAnalysis.dir/LoopCacheAnalysis.cpp.o -c /work/repos/llvm/src/llvm/lib/Analysis/LoopCacheAnalysis.cpp
In file included from /arm/devsys-tools/collections/gcc/7.3.0/1/linux_3.2-ubuntu_12.04-x86_64/gcc-4.6.3-SYSTEM/include/c++/7.3.0/memory:62:0,
                 from /work/repos/llvm/src/llvm/include/llvm/ADT/Optional.h:22,
                 from /work/repos/llvm/src/llvm/include/llvm/ADT/PostOrderIterator.h:19,
                 from /work/repos/llvm/src/llvm/include/llvm/Analysis/LoopAnalysisManager.h:32,
                 from /work/repos/llvm/src/llvm/include/llvm/Analysis/LoopCacheAnalysis.h:17,
                 from /work/repos/llvm/src/llvm/lib/Analysis/LoopCacheAnalysis.cpp:28:
/arm/devsys-tools/collections/gcc/7.3.0/1/linux_3.2-ubuntu_12.04-x86_64/gcc-4.6.3-SYSTEM/include/c++/7.3.0/bits/stl_algobase.h: In instantiation of 'static _OI std::__copy_move<false, false, std::random_access_iterator_tag>::__copy_m(_II, _II, _OI) [with _II = const std::unique_ptr<llvm::IndexedReference>*; _OI = std::unique_ptr<llvm::IndexedReference>*]':
/arm/devsys-tools/collections/gcc/7.3.0/1/linux_3.2-ubuntu_12.04-x86_64/gcc-4.6.3-SYSTEM/include/c++/7.3.0/bits/stl_algobase.h:386:44:   required from '_OI std::__copy_move_a(_II, _II, _OI) [with bool _IsMove = false; _II = const std::unique_ptr<llvm::IndexedReference>*; _OI = std::unique_ptr<llvm::IndexedReference>*]'
/arm/devsys-tools/collections/gcc/7.3.0/1/linux_3.2-ubuntu_12.04-x86_64/gcc-4.6.3-SYSTEM/include/c++/7.3.0/bits/stl_algobase.h:422:45:   required from '_OI std::__copy_move_a2(_II, _II, _OI) [with bool _IsMove = false; _II = const std::unique_ptr<llvm::IndexedReference>*; _OI = std::unique_ptr<llvm::IndexedReference>*]'
/arm/devsys-tools/collections/gcc/7.3.0/1/linux_3.2-ubuntu_12.04-x86_64/gcc-4.6.3-SYSTEM/include/c++/7.3.0/bits/stl_algobase.h:455:8:   required from '_OI std::copy(_II, _II, _OI) [with _II = const std::unique_ptr<llvm::IndexedReference>*; _OI = std::unique_ptr<llvm::IndexedReference>*]'
/work/repos/llvm/src/llvm/include/llvm/ADT/SmallVector.h:842:25:   required from 'llvm::SmallVectorImpl<T>& llvm::SmallVectorImpl<T>::operator=(const llvm::SmallVectorImpl<T>&) [with T = std::unique_ptr<llvm::IndexedReference>]'
/work/repos/llvm/src/llvm/include/llvm/ADT/SmallVector.h:995:36:   required from 'llvm::SmallVector<T, N>::SmallVector(const llvm::SmallVector<T, N>&) [with T = std::unique_ptr<llvm::IndexedReference>; unsigned int N = 8]'
/arm/devsys-tools/collections/gcc/7.3.0/1/linux_3.2-ubuntu_12.04-x86_64/gcc-4.6.3-SYSTEM/include/c++/7.3.0/type_traits:1406:12:   required from 'struct std::is_trivially_copy_constructible<llvm::SmallVector<std::unique_ptr<llvm::IndexedReference>, 8> >'
/work/repos/llvm/src/llvm/include/llvm/ADT/SmallVector.h:281:79:   required from 'class llvm::SmallVectorImpl<llvm::SmallVector<std::unique_ptr<llvm::IndexedReference>, 8> >'
/work/repos/llvm/src/llvm/include/llvm/ADT/SmallVector.h:960:22:   required from 'class llvm::SmallVector<llvm::SmallVector<std::unique_ptr<llvm::IndexedReference>, 8>, 8>'
/work/repos/llvm/src/llvm/lib/Analysis/LoopCacheAnalysis.cpp:522:21:   required from here
/arm/devsys-tools/collections/gcc/7.3.0/1/linux_3.2-ubuntu_12.04-x86_64/gcc-4.6.3-SYSTEM/include/c++/7.3.0/bits/stl_algobase.h:324:18: error: use of deleted function 'std::unique_ptr<_Tp, _Dp>& std::unique_ptr<_Tp, _Dp>::operator=(const std::unique_ptr<_Tp, _Dp>&) [with _Tp = llvm::IndexedReference; _Dp = std::default_delete<llvm::IndexedReference>]'
        *__result = *__first;
        ~~~~~~~~~~^~~~~~~~~~

(the host compiler is GCC 7.3)

mlir/include/mlir/IR/OperationSupport.h

 
 #ifndef MLIR_IR_OPERATION_SUPPORT_H
 #define MLIR_IR_OPERATION_SUPPORT_H
 
 #include "mlir/IR/Attributes.h"
 #include "mlir/IR/BlockSupport.h"
 #include "mlir/IR/Identifier.h"
 #include "mlir/IR/Location.h"
+#include "mlir/IR/Region.h"
 #include "mlir/IR/TypeRange.h"
 #include "mlir/IR/Types.h"
 #include "mlir/IR/Value.h"
 #include "mlir/Support/InterfaceSupport.h"
 #include "llvm/ADT/BitmaskEnum.h"
 #include "llvm/ADT/PointerUnion.h"
 #include "llvm/Support/PointerLikeTypeTraits.h"
 #include "llvm/Support/TrailingObjects.h"
 #include <memory>
 
 namespace mlir {
 class Dialect;
 class Operation;
 struct OperationState;
 class OpAsmParser;
 class OpAsmParserResult;
 class OpAsmPrinter;
 class OperandRange;
 class OpFoldResult;
 class ParseResult;
 class Pattern;
-class Region;
 class ResultRange;
 class RewritePattern;
 class Type;
 class Value;
 class ValueRange;
 template <typename ValueRangeT> class ValueTypeRange;
 
 class OwningRewritePatternList;