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      1 //===-- MachineFunctionPass.h - Pass for MachineFunctions --------*-C++ -*-===//
      2 //
      3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
      4 // See https://llvm.org/LICENSE.txt for license information.
      5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
      6 //
      7 //===----------------------------------------------------------------------===//
      8 //
      9 // This file defines the MachineFunctionPass class.  MachineFunctionPass's are
     10 // just FunctionPass's, except they operate on machine code as part of a code
     11 // generator.  Because they operate on machine code, not the LLVM
     12 // representation, MachineFunctionPass's are not allowed to modify the LLVM
     13 // representation.  Due to this limitation, the MachineFunctionPass class takes
     14 // care of declaring that no LLVM passes are invalidated.
     15 //
     16 //===----------------------------------------------------------------------===//
     17 
     18 #ifndef LLVM_CODEGEN_MACHINEFUNCTIONPASS_H
     19 #define LLVM_CODEGEN_MACHINEFUNCTIONPASS_H
     20 
     21 #include "llvm/CodeGen/MachineFunction.h"
     22 #include "llvm/Pass.h"
     23 
     24 namespace llvm {
     25 
     26 /// MachineFunctionPass - This class adapts the FunctionPass interface to
     27 /// allow convenient creation of passes that operate on the MachineFunction
     28 /// representation. Instead of overriding runOnFunction, subclasses
     29 /// override runOnMachineFunction.
     30 class MachineFunctionPass : public FunctionPass {
     31 public:
     32   bool doInitialization(Module&) override {
     33     // Cache the properties info at module-init time so we don't have to
     34     // construct them for every function.
     35     RequiredProperties = getRequiredProperties();
     36     SetProperties = getSetProperties();
     37     ClearedProperties = getClearedProperties();
     38     return false;
     39   }
     40 protected:
     41   explicit MachineFunctionPass(char &ID) : FunctionPass(ID) {}
     42 
     43   /// runOnMachineFunction - This method must be overloaded to perform the
     44   /// desired machine code transformation or analysis.
     45   ///
     46   virtual bool runOnMachineFunction(MachineFunction &MF) = 0;
     47 
     48   /// getAnalysisUsage - Subclasses that override getAnalysisUsage
     49   /// must call this.
     50   ///
     51   /// For MachineFunctionPasses, calling AU.preservesCFG() indicates that
     52   /// the pass does not modify the MachineBasicBlock CFG.
     53   ///
     54   void getAnalysisUsage(AnalysisUsage &AU) const override;
     55 
     56   virtual MachineFunctionProperties getRequiredProperties() const {
     57     return MachineFunctionProperties();
     58   }
     59   virtual MachineFunctionProperties getSetProperties() const {
     60     return MachineFunctionProperties();
     61   }
     62   virtual MachineFunctionProperties getClearedProperties() const {
     63     return MachineFunctionProperties();
     64   }
     65 
     66 private:
     67   MachineFunctionProperties RequiredProperties;
     68   MachineFunctionProperties SetProperties;
     69   MachineFunctionProperties ClearedProperties;
     70 
     71   /// createPrinterPass - Get a machine function printer pass.
     72   Pass *createPrinterPass(raw_ostream &O,
     73                           const std::string &Banner) const override;
     74 
     75   bool runOnFunction(Function &F) override;
     76 };
     77 
     78 } // End llvm namespace
     79 
     80 #endif
     81