Merge "Update prebuilt Clang to r353983." into p9.0HEADp9.0-backupp9.0

1 files changed, 508 insertions, 0 deletions

diff --git a/clang-r353983/include/llvm/Analysis/CallGraph.h b/clang-r353983/include/llvm/Analysis/CallGraph.h
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+//===- CallGraph.h - Build a Module's call graph ----------------*- 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
+///
+/// This file provides interfaces used to build and manipulate a call graph,
+/// which is a very useful tool for interprocedural optimization.
+///
+/// Every function in a module is represented as a node in the call graph.  The
+/// callgraph node keeps track of which functions are called by the function
+/// corresponding to the node.
+///
+/// A call graph may contain nodes where the function that they correspond to
+/// is null.  These 'external' nodes are used to represent control flow that is
+/// not represented (or analyzable) in the module.  In particular, this
+/// analysis builds one external node such that:
+///   1. All functions in the module without internal linkage will have edges
+///      from this external node, indicating that they could be called by
+///      functions outside of the module.
+///   2. All functions whose address is used for something more than a direct
+///      call, for example being stored into a memory location will also have
+///      an edge from this external node.  Since they may be called by an
+///      unknown caller later, they must be tracked as such.
+///
+/// There is a second external node added for calls that leave this module.
+/// Functions have a call edge to the external node iff:
+///   1. The function is external, reflecting the fact that they could call
+///      anything without internal linkage or that has its address taken.
+///   2. The function contains an indirect function call.
+///
+/// As an extension in the future, there may be multiple nodes with a null
+/// function.  These will be used when we can prove (through pointer analysis)
+/// that an indirect call site can call only a specific set of functions.
+///
+/// Because of these properties, the CallGraph captures a conservative superset
+/// of all of the caller-callee relationships, which is useful for
+/// transformations.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_ANALYSIS_CALLGRAPH_H
+#define LLVM_ANALYSIS_CALLGRAPH_H
+
+#include "llvm/ADT/GraphTraits.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/IR/CallSite.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/Intrinsics.h"
+#include "llvm/IR/PassManager.h"
+#include "llvm/IR/ValueHandle.h"
+#include "llvm/Pass.h"
+#include <cassert>
+#include <map>
+#include <memory>
+#include <utility>
+#include <vector>
+
+namespace llvm {
+
+class CallGraphNode;
+class Module;
+class raw_ostream;
+
+/// The basic data container for the call graph of a \c Module of IR.
+///
+/// This class exposes both the interface to the call graph for a module of IR.
+///
+/// The core call graph itself can also be updated to reflect changes to the IR.
+class CallGraph {
+  Module &M;
+
+  using FunctionMapTy =
+      std::map<const Function *, std::unique_ptr<CallGraphNode>>;
+
+  /// A map from \c Function* to \c CallGraphNode*.
+  FunctionMapTy FunctionMap;
+
+  /// This node has edges to all external functions and those internal
+  /// functions that have their address taken.
+  CallGraphNode *ExternalCallingNode;
+
+  /// This node has edges to it from all functions making indirect calls
+  /// or calling an external function.
+  std::unique_ptr<CallGraphNode> CallsExternalNode;
+
+  /// Replace the function represented by this node by another.
+  ///
+  /// This does not rescan the body of the function, so it is suitable when
+  /// splicing the body of one function to another while also updating all
+  /// callers from the old function to the new.
+  void spliceFunction(const Function *From, const Function *To);
+
+  /// Add a function to the call graph, and link the node to all of the
+  /// functions that it calls.
+  void addToCallGraph(Function *F);
+
+public:
+  explicit CallGraph(Module &M);
+  CallGraph(CallGraph &&Arg);
+  ~CallGraph();
+
+  void print(raw_ostream &OS) const;
+  void dump() const;
+
+  using iterator = FunctionMapTy::iterator;
+  using const_iterator = FunctionMapTy::const_iterator;
+
+  /// Returns the module the call graph corresponds to.
+  Module &getModule() const { return M; }
+
+  inline iterator begin() { return FunctionMap.begin(); }
+  inline iterator end() { return FunctionMap.end(); }
+  inline const_iterator begin() const { return FunctionMap.begin(); }
+  inline const_iterator end() const { return FunctionMap.end(); }
+
+  /// Returns the call graph node for the provided function.
+  inline const CallGraphNode *operator[](const Function *F) const {
+    const_iterator I = FunctionMap.find(F);
+    assert(I != FunctionMap.end() && "Function not in callgraph!");
+    return I->second.get();
+  }
+
+  /// Returns the call graph node for the provided function.
+  inline CallGraphNode *operator[](const Function *F) {
+    const_iterator I = FunctionMap.find(F);
+    assert(I != FunctionMap.end() && "Function not in callgraph!");
+    return I->second.get();
+  }
+
+  /// Returns the \c CallGraphNode which is used to represent
+  /// undetermined calls into the callgraph.
+  CallGraphNode *getExternalCallingNode() const { return ExternalCallingNode; }
+
+  CallGraphNode *getCallsExternalNode() const {
+    return CallsExternalNode.get();
+  }
+
+  //===---------------------------------------------------------------------
+  // Functions to keep a call graph up to date with a function that has been
+  // modified.
+  //
+
+  /// Unlink the function from this module, returning it.
+  ///
+  /// Because this removes the function from the module, the call graph node is
+  /// destroyed.  This is only valid if the function does not call any other
+  /// functions (ie, there are no edges in it's CGN).  The easiest way to do
+  /// this is to dropAllReferences before calling this.
+  Function *removeFunctionFromModule(CallGraphNode *CGN);
+
+  /// Similar to operator[], but this will insert a new CallGraphNode for
+  /// \c F if one does not already exist.
+  CallGraphNode *getOrInsertFunction(const Function *F);
+};
+
+/// A node in the call graph for a module.
+///
+/// Typically represents a function in the call graph. There are also special
+/// "null" nodes used to represent theoretical entries in the call graph.
+class CallGraphNode {
+public:
+  /// A pair of the calling instruction (a call or invoke)
+  /// and the call graph node being called.
+  using CallRecord = std::pair<WeakTrackingVH, CallGraphNode *>;
+
+public:
+  using CalledFunctionsVector = std::vector<CallRecord>;
+
+  /// Creates a node for the specified function.
+  inline CallGraphNode(Function *F) : F(F) {}
+
+  CallGraphNode(const CallGraphNode &) = delete;
+  CallGraphNode &operator=(const CallGraphNode &) = delete;
+
+  ~CallGraphNode() {
+    assert(NumReferences == 0 && "Node deleted while references remain");
+  }
+
+  using iterator = std::vector<CallRecord>::iterator;
+  using const_iterator = std::vector<CallRecord>::const_iterator;
+
+  /// Returns the function that this call graph node represents.
+  Function *getFunction() const { return F; }
+
+  inline iterator begin() { return CalledFunctions.begin(); }
+  inline iterator end() { return CalledFunctions.end(); }
+  inline const_iterator begin() const { return CalledFunctions.begin(); }
+  inline const_iterator end() const { return CalledFunctions.end(); }
+  inline bool empty() const { return CalledFunctions.empty(); }
+  inline unsigned size() const { return (unsigned)CalledFunctions.size(); }
+
+  /// Returns the number of other CallGraphNodes in this CallGraph that
+  /// reference this node in their callee list.
+  unsigned getNumReferences() const { return NumReferences; }
+
+  /// Returns the i'th called function.
+  CallGraphNode *operator[](unsigned i) const {
+    assert(i < CalledFunctions.size() && "Invalid index");
+    return CalledFunctions[i].second;
+  }
+
+  /// Print out this call graph node.
+  void dump() const;
+  void print(raw_ostream &OS) const;
+
+  //===---------------------------------------------------------------------
+  // Methods to keep a call graph up to date with a function that has been
+  // modified
+  //
+
+  /// Removes all edges from this CallGraphNode to any functions it
+  /// calls.
+  void removeAllCalledFunctions() {
+    while (!CalledFunctions.empty()) {
+      CalledFunctions.back().second->DropRef();
+      CalledFunctions.pop_back();
+    }
+  }
+
+  /// Moves all the callee information from N to this node.
+  void stealCalledFunctionsFrom(CallGraphNode *N) {
+    assert(CalledFunctions.empty() &&
+           "Cannot steal callsite information if I already have some");
+    std::swap(CalledFunctions, N->CalledFunctions);
+  }
+
+  /// Adds a function to the list of functions called by this one.
+  void addCalledFunction(CallSite CS, CallGraphNode *M) {
+    assert(!CS.getInstruction() || !CS.getCalledFunction() ||
+           !CS.getCalledFunction()->isIntrinsic() ||
+           !Intrinsic::isLeaf(CS.getCalledFunction()->getIntrinsicID()));
+    CalledFunctions.emplace_back(CS.getInstruction(), M);
+    M->AddRef();
+  }
+
+  void removeCallEdge(iterator I) {
+    I->second->DropRef();
+    *I = CalledFunctions.back();
+    CalledFunctions.pop_back();
+  }
+
+  /// Removes the edge in the node for the specified call site.
+  ///
+  /// Note that this method takes linear time, so it should be used sparingly.
+  void removeCallEdgeFor(CallSite CS);
+
+  /// Removes all call edges from this node to the specified callee
+  /// function.
+  ///
+  /// This takes more time to execute than removeCallEdgeTo, so it should not
+  /// be used unless necessary.
+  void removeAnyCallEdgeTo(CallGraphNode *Callee);
+
+  /// Removes one edge associated with a null callsite from this node to
+  /// the specified callee function.
+  void removeOneAbstractEdgeTo(CallGraphNode *Callee);
+
+  /// Replaces the edge in the node for the specified call site with a
+  /// new one.
+  ///
+  /// Note that this method takes linear time, so it should be used sparingly.
+  void replaceCallEdge(CallSite CS, CallSite NewCS, CallGraphNode *NewNode);
+
+private:
+  friend class CallGraph;
+
+  Function *F;
+
+  std::vector<CallRecord> CalledFunctions;
+
+  /// The number of times that this CallGraphNode occurs in the
+  /// CalledFunctions array of this or other CallGraphNodes.
+  unsigned NumReferences = 0;
+
+  void DropRef() { --NumReferences; }
+  void AddRef() { ++NumReferences; }
+
+  /// A special function that should only be used by the CallGraph class.
+  void allReferencesDropped() { NumReferences = 0; }
+};
+
+/// An analysis pass to compute the \c CallGraph for a \c Module.
+///
+/// This class implements the concept of an analysis pass used by the \c
+/// ModuleAnalysisManager to run an analysis over a module and cache the
+/// resulting data.
+class CallGraphAnalysis : public AnalysisInfoMixin<CallGraphAnalysis> {
+  friend AnalysisInfoMixin<CallGraphAnalysis>;
+
+  static AnalysisKey Key;
+
+public:
+  /// A formulaic type to inform clients of the result type.
+  using Result = CallGraph;
+
+  /// Compute the \c CallGraph for the module \c M.
+  ///
+  /// The real work here is done in the \c CallGraph constructor.
+  CallGraph run(Module &M, ModuleAnalysisManager &) { return CallGraph(M); }
+};
+
+/// Printer pass for the \c CallGraphAnalysis results.
+class CallGraphPrinterPass : public PassInfoMixin<CallGraphPrinterPass> {
+  raw_ostream &OS;
+
+public:
+  explicit CallGraphPrinterPass(raw_ostream &OS) : OS(OS) {}
+
+  PreservedAnalyses run(Module &M, ModuleAnalysisManager &AM);
+};
+
+/// The \c ModulePass which wraps up a \c CallGraph and the logic to
+/// build it.
+///
+/// This class exposes both the interface to the call graph container and the
+/// module pass which runs over a module of IR and produces the call graph. The
+/// call graph interface is entirelly a wrapper around a \c CallGraph object
+/// which is stored internally for each module.
+class CallGraphWrapperPass : public ModulePass {
+  std::unique_ptr<CallGraph> G;
+
+public:
+  static char ID; // Class identification, replacement for typeinfo
+
+  CallGraphWrapperPass();
+  ~CallGraphWrapperPass() override;
+
+  /// The internal \c CallGraph around which the rest of this interface
+  /// is wrapped.
+  const CallGraph &getCallGraph() const { return *G; }
+  CallGraph &getCallGraph() { return *G; }
+
+  using iterator = CallGraph::iterator;
+  using const_iterator = CallGraph::const_iterator;
+
+  /// Returns the module the call graph corresponds to.
+  Module &getModule() const { return G->getModule(); }
+
+  inline iterator begin() { return G->begin(); }
+  inline iterator end() { return G->end(); }
+  inline const_iterator begin() const { return G->begin(); }
+  inline const_iterator end() const { return G->end(); }
+
+  /// Returns the call graph node for the provided function.
+  inline const CallGraphNode *operator[](const Function *F) const {
+    return (*G)[F];
+  }
+
+  /// Returns the call graph node for the provided function.
+  inline CallGraphNode *operator[](const Function *F) { return (*G)[F]; }
+
+  /// Returns the \c CallGraphNode which is used to represent
+  /// undetermined calls into the callgraph.
+  CallGraphNode *getExternalCallingNode() const {
+    return G->getExternalCallingNode();
+  }
+
+  CallGraphNode *getCallsExternalNode() const {
+    return G->getCallsExternalNode();
+  }
+
+  //===---------------------------------------------------------------------
+  // Functions to keep a call graph up to date with a function that has been
+  // modified.
+  //
+
+  /// Unlink the function from this module, returning it.
+  ///
+  /// Because this removes the function from the module, the call graph node is
+  /// destroyed.  This is only valid if the function does not call any other
+  /// functions (ie, there are no edges in it's CGN).  The easiest way to do
+  /// this is to dropAllReferences before calling this.
+  Function *removeFunctionFromModule(CallGraphNode *CGN) {
+    return G->removeFunctionFromModule(CGN);
+  }
+
+  /// Similar to operator[], but this will insert a new CallGraphNode for
+  /// \c F if one does not already exist.
+  CallGraphNode *getOrInsertFunction(const Function *F) {
+    return G->getOrInsertFunction(F);
+  }
+
+  //===---------------------------------------------------------------------
+  // Implementation of the ModulePass interface needed here.
+  //
+
+  void getAnalysisUsage(AnalysisUsage &AU) const override;
+  bool runOnModule(Module &M) override;
+  void releaseMemory() override;
+
+  void print(raw_ostream &o, const Module *) const override;
+  void dump() const;
+};
+
+//===----------------------------------------------------------------------===//
+// GraphTraits specializations for call graphs so that they can be treated as
+// graphs by the generic graph algorithms.
+//
+
+// Provide graph traits for tranversing call graphs using standard graph
+// traversals.
+template <> struct GraphTraits<CallGraphNode *> {
+  using NodeRef = CallGraphNode *;
+  using CGNPairTy = CallGraphNode::CallRecord;
+
+  static NodeRef getEntryNode(CallGraphNode *CGN) { return CGN; }
+  static CallGraphNode *CGNGetValue(CGNPairTy P) { return P.second; }
+
+  using ChildIteratorType =
+      mapped_iterator<CallGraphNode::iterator, decltype(&CGNGetValue)>;
+
+  static ChildIteratorType child_begin(NodeRef N) {
+    return ChildIteratorType(N->begin(), &CGNGetValue);
+  }
+
+  static ChildIteratorType child_end(NodeRef N) {
+    return ChildIteratorType(N->end(), &CGNGetValue);
+  }
+};
+
+template <> struct GraphTraits<const CallGraphNode *> {
+  using NodeRef = const CallGraphNode *;
+  using CGNPairTy = CallGraphNode::CallRecord;
+  using EdgeRef = const CallGraphNode::CallRecord &;
+
+  static NodeRef getEntryNode(const CallGraphNode *CGN) { return CGN; }
+  static const CallGraphNode *CGNGetValue(CGNPairTy P) { return P.second; }
+
+  using ChildIteratorType =
+      mapped_iterator<CallGraphNode::const_iterator, decltype(&CGNGetValue)>;
+  using ChildEdgeIteratorType = CallGraphNode::const_iterator;
+
+  static ChildIteratorType child_begin(NodeRef N) {
+    return ChildIteratorType(N->begin(), &CGNGetValue);
+  }
+
+  static ChildIteratorType child_end(NodeRef N) {
+    return ChildIteratorType(N->end(), &CGNGetValue);
+  }
+
+  static ChildEdgeIteratorType child_edge_begin(NodeRef N) {
+    return N->begin();
+  }
+  static ChildEdgeIteratorType child_edge_end(NodeRef N) { return N->end(); }
+
+  static NodeRef edge_dest(EdgeRef E) { return E.second; }
+};
+
+template <>
+struct GraphTraits<CallGraph *> : public GraphTraits<CallGraphNode *> {
+  using PairTy =
+      std::pair<const Function *const, std::unique_ptr<CallGraphNode>>;
+
+  static NodeRef getEntryNode(CallGraph *CGN) {
+    return CGN->getExternalCallingNode(); // Start at the external node!
+  }
+
+  static CallGraphNode *CGGetValuePtr(const PairTy &P) {
+    return P.second.get();
+  }
+
+  // nodes_iterator/begin/end - Allow iteration over all nodes in the graph
+  using nodes_iterator =
+      mapped_iterator<CallGraph::iterator, decltype(&CGGetValuePtr)>;
+
+  static nodes_iterator nodes_begin(CallGraph *CG) {
+    return nodes_iterator(CG->begin(), &CGGetValuePtr);
+  }
+
+  static nodes_iterator nodes_end(CallGraph *CG) {
+    return nodes_iterator(CG->end(), &CGGetValuePtr);
+  }
+};
+
+template <>
+struct GraphTraits<const CallGraph *> : public GraphTraits<
+                                            const CallGraphNode *> {
+  using PairTy =
+      std::pair<const Function *const, std::unique_ptr<CallGraphNode>>;
+
+  static NodeRef getEntryNode(const CallGraph *CGN) {
+    return CGN->getExternalCallingNode(); // Start at the external node!
+  }
+
+  static const CallGraphNode *CGGetValuePtr(const PairTy &P) {
+    return P.second.get();
+  }
+
+  // nodes_iterator/begin/end - Allow iteration over all nodes in the graph
+  using nodes_iterator =
+      mapped_iterator<CallGraph::const_iterator, decltype(&CGGetValuePtr)>;
+
+  static nodes_iterator nodes_begin(const CallGraph *CG) {
+    return nodes_iterator(CG->begin(), &CGGetValuePtr);
+  }
+
+  static nodes_iterator nodes_end(const CallGraph *CG) {
+    return nodes_iterator(CG->end(), &CGGetValuePtr);
+  }
+};
+
+} // end namespace llvm
+
+#endif // LLVM_ANALYSIS_CALLGRAPH_H