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diff --git a/lib/Transforms/Instrumentation/ValueProfileCollector.cpp b/lib/Transforms/Instrumentation/ValueProfileCollector.cpp
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+++ b/lib/Transforms/Instrumentation/ValueProfileCollector.cpp
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+//===- ValueProfileCollector.cpp - determine what to value profile --------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// The implementation of the ValueProfileCollector via ValueProfileCollectorImpl
+//
+//===----------------------------------------------------------------------===//
+
+#include "ValueProfilePlugins.inc"
+#include "llvm/IR/InstIterator.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/InitializePasses.h"
+
+#include <cassert>
+
+using namespace llvm;
+
+namespace {
+
+/// A plugin-based class that takes an arbitrary number of Plugin types.
+/// Each plugin type must satisfy the following API:
+///  1) the constructor must take a `Function &f`. Typically, the plugin would
+///     scan the function looking for candidates.
+///  2) contain a member function with the following signature and name:
+///        void run(std::vector<CandidateInfo> &Candidates);
+///    such that the plugin would append its result into the vector parameter.
+///
+/// Plugins are defined in ValueProfilePlugins.inc
+template <class... Ts> class PluginChain;
+
+/// The type PluginChainFinal is the final chain of plugins that will be used by
+/// ValueProfileCollectorImpl.
+using PluginChainFinal = PluginChain<VP_PLUGIN_LIST>;
+
+template <> class PluginChain<> {
+public:
+  PluginChain(Function &F) {}
+  void get(InstrProfValueKind K, std::vector<CandidateInfo> &Candidates) {}
+};
+
+template <class PluginT, class... Ts>
+class PluginChain<PluginT, Ts...> : public PluginChain<Ts...> {
+  PluginT Plugin;
+  using Base = PluginChain<Ts...>;
+
+public:
+  PluginChain(Function &F) : PluginChain<Ts...>(F), Plugin(F) {}
+
+  void get(InstrProfValueKind K, std::vector<CandidateInfo> &Candidates) {
+    if (K == PluginT::Kind)
+      Plugin.run(Candidates);
+    Base::get(K, Candidates);
+  }
+};
+
+} // end anonymous namespace
+
+/// ValueProfileCollectorImpl inherits the API of PluginChainFinal.
+class ValueProfileCollector::ValueProfileCollectorImpl : public PluginChainFinal {
+public:
+  using PluginChainFinal::PluginChainFinal;
+};
+
+ValueProfileCollector::ValueProfileCollector(Function &F)
+    : PImpl(new ValueProfileCollectorImpl(F)) {}
+
+ValueProfileCollector::~ValueProfileCollector() = default;
+
+std::vector<CandidateInfo>
+ValueProfileCollector::get(InstrProfValueKind Kind) const {
+  std::vector<CandidateInfo> Result;
+  PImpl->get(Kind, Result);
+  return Result;
+}