Workaround an assertion failure during module build

[steven_wu]

Summary

After the change in https://reviews.llvm.org/D131858, clang cannot
bootstrap itself with modules due to assertion failure:
(lvaluePath->getType() == elemTy && "Unexpected type reference!")

Workaround the assertion by converting some of the includes into forward
declares.

llvm/include/llvm/ExecutionEngine/Orc/CompileOnDemandLayer.h

 #include "llvm/IR/GlobalValue.h"
 #include "llvm/IR/GlobalVariable.h"
 #include "llvm/IR/Instruction.h"
 #include "llvm/IR/Mangler.h"
 #include "llvm/IR/Module.h"
 #include "llvm/IR/Type.h"
 #include "llvm/Support/Casting.h"
 #include "llvm/Support/raw_ostream.h"
-#include "llvm/Transforms/Utils/ValueMapper.h"
 #include <algorithm>
 #include <cassert>
 #include <functional>
 #include <iterator>
 #include <list>
 #include <memory>
 #include <set>
 #include <utility>

llvm/include/llvm/ExecutionEngine/Orc/IndirectionUtils.h

 #ifndef LLVM_EXECUTIONENGINE_ORC_INDIRECTIONUTILS_H
 #define LLVM_EXECUTIONENGINE_ORC_INDIRECTIONUTILS_H
 
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ExecutionEngine/JITSymbol.h"
 #include "llvm/ExecutionEngine/Orc/Core.h"
 #include "llvm/ExecutionEngine/Orc/OrcABISupport.h"
+#include "llvm/IR/ValueHandle.h"
+#include "llvm/IR/ValueMap.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/Memory.h"
 #include "llvm/Support/Process.h"
-#include "llvm/Transforms/Utils/ValueMapper.h"
 #include <algorithm>
 #include <cassert>
 #include <cstdint>
 #include <functional>
 #include <future>
 #include <map>
 #include <memory>
 #include <system_error>

 class GlobalVariable;
 class Module;
 class PointerType;
 class Triple;
 class Twine;
 class Value;
 class MCDisassembler;
 class MCInstrAnalysis;
+class ValueMaterializer;
+
+using ValueToValueMapTy = ValueMap<const Value *, WeakTrackingVH>;
 
 namespace jitlink {
 class LinkGraph;
 class Symbol;
 } // namespace jitlink
 
 namespace orc {
 

llvm/include/llvm/ExecutionEngine/Orc/SpeculateAnalyses.h

 //===-- SpeculateAnalyses.h  --*- C++ -*-===//
 //
 // 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
 //
 //===----------------------------------------------------------------------===//
 /// \file
 /// Contains the Analyses and Result Interpretation to select likely functions
 /// to Speculatively compile before they are called. [Purely Experimentation]
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_EXECUTIONENGINE_ORC_SPECULATEANALYSES_H
 #define LLVM_EXECUTIONENGINE_ORC_SPECULATEANALYSES_H
 
-#include "llvm/Analysis/BranchProbabilityInfo.h"
 #include "llvm/ExecutionEngine/Orc/Core.h"
 #include "llvm/ExecutionEngine/Orc/Speculation.h"
 
 #include <vector>
 
 namespace llvm {
 
+class BranchProbabilityInfo;
+
 namespace orc {
 
 // Provides common code.
 class SpeculateQuery {
 protected:
   void findCalles(const BasicBlock *, DenseSet<StringRef> &);
   bool isStraightLine(const Function &F);