unittests/IR/CFGBuilder.h

   1 //===- CFGBuilder.h - CFG building and updating utility ----------*- C++ -*-==//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 /// \file
  10 /// CFGBuilders provides utilities fo building and updating CFG for testing
  11 /// purposes.
  12 ///
  13 //===----------------------------------------------------------------------===//
  14
  15 #ifndef LLVM_UNITTESTS_CFG_BUILDER_H
  16 #define LLVM_UNITTESTS_CFG_BUILDER_H
  17
  18 #include "llvm/ADT/DenseMap.h"
  19 #include "llvm/ADT/Optional.h"
  20 #include "llvm/ADT/StringMap.h"
  21 #include "llvm/ADT/StringRef.h"
  22 #include "llvm/Support/Debug.h"
  23
  24 #include <memory>
  25 #include <set>
  26 #include <tuple>
  27 #include <vector>
  28
  29 namespace llvm {
  30
  31 class LLVMContext;
  32 class Module;
  33 class Function;
  34 class BasicBlock;
  35 class raw_ostream;
  36
  37 struct CFGHolder {
  38   std::unique_ptr<LLVMContext> Context;
  39   std::unique_ptr<Module> M;
  40   Function *F;
  41
  42   CFGHolder(StringRef ModuleName = "m", StringRef FunctionName = "foo");
  43   ~CFGHolder(); // Defined in the .cpp file so we can use forward declarations.
  44 };
  45
  46 /// \brief
  47 /// CFGBuilder builds IR with specific CFG, based on the supplied list of arcs.
  48 /// It's able to apply the provided updates and automatically modify the IR.
  49 ///
  50 /// Internally it makes every basic block end with either SwitchInst or with
  51 /// UnreachableInst. When all arc to a BB are deleted, the BB remains in the
  52 /// function and doesn't get deleted.
  53 ///
  54 class CFGBuilder {
  55 public:
  56   struct Arc {
  57     StringRef From;
  58     StringRef To;
  59
  60     friend bool operator<(const Arc &LHS, const Arc &RHS) {
  61       return std::tie(LHS.From, LHS.To) <
  62              std::tie(RHS.From, RHS.To);
  63     }
  64   };
  65
  66   enum class ActionKind { Insert, Delete };
  67   struct Update {
  68     ActionKind Action;
  69     Arc Edge;
  70   };
  71
  72   CFGBuilder(Function *F, const std::vector<Arc> &InitialArcs,
  73              std::vector<Update> Updates);
  74
  75   BasicBlock *getOrAddBlock(StringRef BlockName);
  76   Optional<Update> getNextUpdate() const;
  77   Optional<Update> applyUpdate();
  78   void dump(raw_ostream &OS = dbgs()) const;
  79
  80 private:
  81   void buildCFG(const std::vector<Arc> &Arcs);
  82   bool connect(const Arc &A);
  83   bool disconnect(const Arc &A);
  84
  85   Function *F;
  86   unsigned UpdateIdx = 0;
  87   StringMap<BasicBlock *> NameToBlock;
  88   std::set<Arc> Arcs;
  89   std::vector<Update> Updates;
  90 };
  91
  92 } // namespace llvm
  93
  94 #endif