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The specializations were broken. For example, void foo(const CallGraph *G) { auto I = GraphTraits<const CallGraph *>::nodes_begin(G); auto K = I++; ... } or void bar(const CallGraphNode *N) { auto I = GraphTraits<const CallGraphNode *>::nodes_begin(G); auto K = I++; .... } would not compile. Patch by Speziale Ettore! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222149 91177308-0d34-0410-b5e6-96231b3b80d8
485 lines
18 KiB
C++
485 lines
18 KiB
C++
//===- CallGraph.h - Build a Module's call graph ----------------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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/// \file
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///
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/// This file provides interfaces used to build and manipulate a call graph,
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/// which is a very useful tool for interprocedural optimization.
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///
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/// Every function in a module is represented as a node in the call graph. The
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/// callgraph node keeps track of which functions are called by the function
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/// corresponding to the node.
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///
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/// A call graph may contain nodes where the function that they correspond to
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/// is null. These 'external' nodes are used to represent control flow that is
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/// not represented (or analyzable) in the module. In particular, this
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/// analysis builds one external node such that:
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/// 1. All functions in the module without internal linkage will have edges
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/// from this external node, indicating that they could be called by
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/// functions outside of the module.
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/// 2. All functions whose address is used for something more than a direct
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/// call, for example being stored into a memory location will also have
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/// an edge from this external node. Since they may be called by an
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/// unknown caller later, they must be tracked as such.
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///
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/// There is a second external node added for calls that leave this module.
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/// Functions have a call edge to the external node iff:
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/// 1. The function is external, reflecting the fact that they could call
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/// anything without internal linkage or that has its address taken.
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/// 2. The function contains an indirect function call.
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///
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/// As an extension in the future, there may be multiple nodes with a null
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/// function. These will be used when we can prove (through pointer analysis)
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/// that an indirect call site can call only a specific set of functions.
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///
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/// Because of these properties, the CallGraph captures a conservative superset
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/// of all of the caller-callee relationships, which is useful for
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/// transformations.
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///
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/// The CallGraph class also attempts to figure out what the root of the
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/// CallGraph is, which it currently does by looking for a function named
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/// 'main'. If no function named 'main' is found, the external node is used as
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/// the entry node, reflecting the fact that any function without internal
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/// linkage could be called into (which is common for libraries).
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///
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_ANALYSIS_CALLGRAPH_H
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#define LLVM_ANALYSIS_CALLGRAPH_H
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#include "llvm/ADT/GraphTraits.h"
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#include "llvm/ADT/STLExtras.h"
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#include "llvm/IR/CallSite.h"
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#include "llvm/IR/Function.h"
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#include "llvm/IR/ValueHandle.h"
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#include "llvm/Pass.h"
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#include <map>
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namespace llvm {
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class Function;
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class Module;
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class CallGraphNode;
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/// \brief The basic data container for the call graph of a \c Module of IR.
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///
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/// This class exposes both the interface to the call graph for a module of IR.
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///
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/// The core call graph itself can also be updated to reflect changes to the IR.
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class CallGraph {
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Module &M;
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typedef std::map<const Function *, CallGraphNode *> FunctionMapTy;
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/// \brief A map from \c Function* to \c CallGraphNode*.
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FunctionMapTy FunctionMap;
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/// \brief Root is root of the call graph, or the external node if a 'main'
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/// function couldn't be found.
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CallGraphNode *Root;
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/// \brief This node has edges to all external functions and those internal
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/// functions that have their address taken.
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CallGraphNode *ExternalCallingNode;
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/// \brief This node has edges to it from all functions making indirect calls
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/// or calling an external function.
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CallGraphNode *CallsExternalNode;
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/// \brief Replace the function represented by this node by another.
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///
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/// This does not rescan the body of the function, so it is suitable when
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/// splicing the body of one function to another while also updating all
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/// callers from the old function to the new.
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void spliceFunction(const Function *From, const Function *To);
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/// \brief Add a function to the call graph, and link the node to all of the
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/// functions that it calls.
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void addToCallGraph(Function *F);
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public:
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CallGraph(Module &M);
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~CallGraph();
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void print(raw_ostream &OS) const;
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void dump() const;
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typedef FunctionMapTy::iterator iterator;
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typedef FunctionMapTy::const_iterator const_iterator;
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/// \brief Returns the module the call graph corresponds to.
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Module &getModule() const { return M; }
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inline iterator begin() { return FunctionMap.begin(); }
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inline iterator end() { return FunctionMap.end(); }
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inline const_iterator begin() const { return FunctionMap.begin(); }
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inline const_iterator end() const { return FunctionMap.end(); }
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/// \brief Returns the call graph node for the provided function.
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inline const CallGraphNode *operator[](const Function *F) const {
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const_iterator I = FunctionMap.find(F);
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assert(I != FunctionMap.end() && "Function not in callgraph!");
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return I->second;
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}
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/// \brief Returns the call graph node for the provided function.
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inline CallGraphNode *operator[](const Function *F) {
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const_iterator I = FunctionMap.find(F);
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assert(I != FunctionMap.end() && "Function not in callgraph!");
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return I->second;
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}
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/// \brief Returns the \c CallGraphNode which is used to represent
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/// undetermined calls into the callgraph.
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CallGraphNode *getExternalCallingNode() const { return ExternalCallingNode; }
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CallGraphNode *getCallsExternalNode() const { return CallsExternalNode; }
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//===---------------------------------------------------------------------
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// Functions to keep a call graph up to date with a function that has been
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// modified.
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//
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/// \brief Unlink the function from this module, returning it.
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///
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/// Because this removes the function from the module, the call graph node is
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/// destroyed. This is only valid if the function does not call any other
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/// functions (ie, there are no edges in it's CGN). The easiest way to do
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/// this is to dropAllReferences before calling this.
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Function *removeFunctionFromModule(CallGraphNode *CGN);
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/// \brief Similar to operator[], but this will insert a new CallGraphNode for
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/// \c F if one does not already exist.
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CallGraphNode *getOrInsertFunction(const Function *F);
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};
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/// \brief A node in the call graph for a module.
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///
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/// Typically represents a function in the call graph. There are also special
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/// "null" nodes used to represent theoretical entries in the call graph.
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class CallGraphNode {
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public:
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/// \brief A pair of the calling instruction (a call or invoke)
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/// and the call graph node being called.
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typedef std::pair<WeakVH, CallGraphNode *> CallRecord;
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public:
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typedef std::vector<CallRecord> CalledFunctionsVector;
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/// \brief Creates a node for the specified function.
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inline CallGraphNode(Function *F) : F(F), NumReferences(0) {}
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~CallGraphNode() {
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assert(NumReferences == 0 && "Node deleted while references remain");
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}
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typedef std::vector<CallRecord>::iterator iterator;
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typedef std::vector<CallRecord>::const_iterator const_iterator;
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/// \brief Returns the function that this call graph node represents.
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Function *getFunction() const { return F; }
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inline iterator begin() { return CalledFunctions.begin(); }
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inline iterator end() { return CalledFunctions.end(); }
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inline const_iterator begin() const { return CalledFunctions.begin(); }
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inline const_iterator end() const { return CalledFunctions.end(); }
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inline bool empty() const { return CalledFunctions.empty(); }
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inline unsigned size() const { return (unsigned)CalledFunctions.size(); }
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/// \brief Returns the number of other CallGraphNodes in this CallGraph that
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/// reference this node in their callee list.
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unsigned getNumReferences() const { return NumReferences; }
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/// \brief Returns the i'th called function.
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CallGraphNode *operator[](unsigned i) const {
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assert(i < CalledFunctions.size() && "Invalid index");
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return CalledFunctions[i].second;
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}
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/// \brief Print out this call graph node.
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void dump() const;
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void print(raw_ostream &OS) const;
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//===---------------------------------------------------------------------
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// Methods to keep a call graph up to date with a function that has been
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// modified
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//
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/// \brief Removes all edges from this CallGraphNode to any functions it
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/// calls.
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void removeAllCalledFunctions() {
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while (!CalledFunctions.empty()) {
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CalledFunctions.back().second->DropRef();
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CalledFunctions.pop_back();
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}
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}
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/// \brief Moves all the callee information from N to this node.
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void stealCalledFunctionsFrom(CallGraphNode *N) {
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assert(CalledFunctions.empty() &&
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"Cannot steal callsite information if I already have some");
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std::swap(CalledFunctions, N->CalledFunctions);
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}
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/// \brief Adds a function to the list of functions called by this one.
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void addCalledFunction(CallSite CS, CallGraphNode *M) {
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assert(!CS.getInstruction() || !CS.getCalledFunction() ||
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!CS.getCalledFunction()->isIntrinsic());
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CalledFunctions.push_back(std::make_pair(CS.getInstruction(), M));
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M->AddRef();
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}
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void removeCallEdge(iterator I) {
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I->second->DropRef();
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*I = CalledFunctions.back();
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CalledFunctions.pop_back();
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}
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/// \brief Removes the edge in the node for the specified call site.
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///
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/// Note that this method takes linear time, so it should be used sparingly.
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void removeCallEdgeFor(CallSite CS);
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/// \brief Removes all call edges from this node to the specified callee
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/// function.
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///
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/// This takes more time to execute than removeCallEdgeTo, so it should not
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/// be used unless necessary.
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void removeAnyCallEdgeTo(CallGraphNode *Callee);
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/// \brief Removes one edge associated with a null callsite from this node to
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/// the specified callee function.
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void removeOneAbstractEdgeTo(CallGraphNode *Callee);
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/// \brief Replaces the edge in the node for the specified call site with a
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/// new one.
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///
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/// Note that this method takes linear time, so it should be used sparingly.
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void replaceCallEdge(CallSite CS, CallSite NewCS, CallGraphNode *NewNode);
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private:
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friend class CallGraph;
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AssertingVH<Function> F;
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std::vector<CallRecord> CalledFunctions;
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/// \brief The number of times that this CallGraphNode occurs in the
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/// CalledFunctions array of this or other CallGraphNodes.
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unsigned NumReferences;
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CallGraphNode(const CallGraphNode &) LLVM_DELETED_FUNCTION;
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void operator=(const CallGraphNode &) LLVM_DELETED_FUNCTION;
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void DropRef() { --NumReferences; }
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void AddRef() { ++NumReferences; }
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/// \brief A special function that should only be used by the CallGraph class.
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void allReferencesDropped() { NumReferences = 0; }
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};
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/// \brief An analysis pass to compute the \c CallGraph for a \c Module.
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///
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/// This class implements the concept of an analysis pass used by the \c
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/// ModuleAnalysisManager to run an analysis over a module and cache the
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/// resulting data.
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class CallGraphAnalysis {
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public:
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/// \brief A formulaic typedef to inform clients of the result type.
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typedef CallGraph Result;
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static void *ID() { return (void *)&PassID; }
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/// \brief Compute the \c CallGraph for the module \c M.
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///
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/// The real work here is done in the \c CallGraph constructor.
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CallGraph run(Module *M) { return CallGraph(*M); }
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private:
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static char PassID;
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};
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/// \brief The \c ModulePass which wraps up a \c CallGraph and the logic to
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/// build it.
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///
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/// This class exposes both the interface to the call graph container and the
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/// module pass which runs over a module of IR and produces the call graph. The
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/// call graph interface is entirelly a wrapper around a \c CallGraph object
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/// which is stored internally for each module.
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class CallGraphWrapperPass : public ModulePass {
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std::unique_ptr<CallGraph> G;
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public:
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static char ID; // Class identification, replacement for typeinfo
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CallGraphWrapperPass();
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virtual ~CallGraphWrapperPass();
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/// \brief The internal \c CallGraph around which the rest of this interface
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/// is wrapped.
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const CallGraph &getCallGraph() const { return *G; }
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CallGraph &getCallGraph() { return *G; }
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typedef CallGraph::iterator iterator;
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typedef CallGraph::const_iterator const_iterator;
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/// \brief Returns the module the call graph corresponds to.
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Module &getModule() const { return G->getModule(); }
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inline iterator begin() { return G->begin(); }
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inline iterator end() { return G->end(); }
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inline const_iterator begin() const { return G->begin(); }
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inline const_iterator end() const { return G->end(); }
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/// \brief Returns the call graph node for the provided function.
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inline const CallGraphNode *operator[](const Function *F) const {
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return (*G)[F];
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}
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/// \brief Returns the call graph node for the provided function.
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inline CallGraphNode *operator[](const Function *F) { return (*G)[F]; }
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/// \brief Returns the \c CallGraphNode which is used to represent
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/// undetermined calls into the callgraph.
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CallGraphNode *getExternalCallingNode() const {
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return G->getExternalCallingNode();
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}
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CallGraphNode *getCallsExternalNode() const {
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return G->getCallsExternalNode();
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}
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//===---------------------------------------------------------------------
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// Functions to keep a call graph up to date with a function that has been
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// modified.
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//
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/// \brief Unlink the function from this module, returning it.
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///
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/// Because this removes the function from the module, the call graph node is
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/// destroyed. This is only valid if the function does not call any other
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/// functions (ie, there are no edges in it's CGN). The easiest way to do
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/// this is to dropAllReferences before calling this.
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Function *removeFunctionFromModule(CallGraphNode *CGN) {
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return G->removeFunctionFromModule(CGN);
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}
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/// \brief Similar to operator[], but this will insert a new CallGraphNode for
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/// \c F if one does not already exist.
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CallGraphNode *getOrInsertFunction(const Function *F) {
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return G->getOrInsertFunction(F);
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}
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//===---------------------------------------------------------------------
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// Implementation of the ModulePass interface needed here.
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//
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void getAnalysisUsage(AnalysisUsage &AU) const override;
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bool runOnModule(Module &M) override;
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void releaseMemory() override;
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void print(raw_ostream &o, const Module *) const override;
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void dump() const;
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};
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//===----------------------------------------------------------------------===//
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// GraphTraits specializations for call graphs so that they can be treated as
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// graphs by the generic graph algorithms.
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//
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// Provide graph traits for tranversing call graphs using standard graph
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// traversals.
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template <> struct GraphTraits<CallGraphNode *> {
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typedef CallGraphNode NodeType;
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typedef CallGraphNode::CallRecord CGNPairTy;
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typedef std::pointer_to_unary_function<CGNPairTy, CallGraphNode *>
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CGNDerefFun;
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static NodeType *getEntryNode(CallGraphNode *CGN) { return CGN; }
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typedef mapped_iterator<NodeType::iterator, CGNDerefFun> ChildIteratorType;
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static inline ChildIteratorType child_begin(NodeType *N) {
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return map_iterator(N->begin(), CGNDerefFun(CGNDeref));
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}
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static inline ChildIteratorType child_end(NodeType *N) {
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return map_iterator(N->end(), CGNDerefFun(CGNDeref));
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}
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static CallGraphNode *CGNDeref(CGNPairTy P) { return P.second; }
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};
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template <> struct GraphTraits<const CallGraphNode *> {
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typedef const CallGraphNode NodeType;
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typedef CallGraphNode::CallRecord CGNPairTy;
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typedef std::pointer_to_unary_function<CGNPairTy, const CallGraphNode *>
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CGNDerefFun;
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static NodeType *getEntryNode(const CallGraphNode *CGN) { return CGN; }
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typedef mapped_iterator<NodeType::const_iterator, CGNDerefFun>
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ChildIteratorType;
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static inline ChildIteratorType child_begin(NodeType *N) {
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return map_iterator(N->begin(), CGNDerefFun(CGNDeref));
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}
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static inline ChildIteratorType child_end(NodeType *N) {
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return map_iterator(N->end(), CGNDerefFun(CGNDeref));
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}
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static const CallGraphNode *CGNDeref(CGNPairTy P) { return P.second; }
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};
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template <>
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struct GraphTraits<CallGraph *> : public GraphTraits<CallGraphNode *> {
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static NodeType *getEntryNode(CallGraph *CGN) {
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return CGN->getExternalCallingNode(); // Start at the external node!
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}
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typedef std::pair<const Function *, CallGraphNode *> PairTy;
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typedef std::pointer_to_unary_function<PairTy, CallGraphNode &> DerefFun;
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// nodes_iterator/begin/end - Allow iteration over all nodes in the graph
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typedef mapped_iterator<CallGraph::iterator, DerefFun> nodes_iterator;
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static nodes_iterator nodes_begin(CallGraph *CG) {
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return map_iterator(CG->begin(), DerefFun(CGdereference));
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}
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static nodes_iterator nodes_end(CallGraph *CG) {
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return map_iterator(CG->end(), DerefFun(CGdereference));
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}
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static CallGraphNode &CGdereference(PairTy P) { return *P.second; }
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};
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template <>
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struct GraphTraits<const CallGraph *> : public GraphTraits<
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const CallGraphNode *> {
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static NodeType *getEntryNode(const CallGraph *CGN) {
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return CGN->getExternalCallingNode(); // Start at the external node!
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}
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typedef std::pair<const Function *, const CallGraphNode *> PairTy;
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typedef std::pointer_to_unary_function<PairTy, const CallGraphNode &>
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DerefFun;
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// nodes_iterator/begin/end - Allow iteration over all nodes in the graph
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typedef mapped_iterator<CallGraph::const_iterator, DerefFun> nodes_iterator;
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static nodes_iterator nodes_begin(const CallGraph *CG) {
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return map_iterator(CG->begin(), DerefFun(CGdereference));
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}
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static nodes_iterator nodes_end(const CallGraph *CG) {
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return map_iterator(CG->end(), DerefFun(CGdereference));
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}
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static const CallGraphNode &CGdereference(PairTy P) { return *P.second; }
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};
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} // End llvm namespace
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#endif
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