PrologEpilogInserter.h revision 263508 
1//===-- PrologEpilogInserter.h - Prolog/Epilog code insertion -*- 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//
10// This pass is responsible for finalizing the functions frame layout, saving
11// callee saved registers, and for emitting prolog & epilog code for the
12// function.
13//
14// This pass must be run after register allocation.  After this pass is
15// executed, it is illegal to construct MO_FrameIndex operands.
16//
17//===----------------------------------------------------------------------===//
18
19#ifndef LLVM_CODEGEN_PEI_H
20#define LLVM_CODEGEN_PEI_H
21
22#include "llvm/ADT/DenseMap.h"
23#include "llvm/ADT/SparseBitVector.h"
24#include "llvm/CodeGen/MachineFunctionPass.h"
25#include "llvm/CodeGen/MachineLoopInfo.h"
26#include "llvm/CodeGen/Passes.h"
27#include "llvm/Target/TargetRegisterInfo.h"
28
29namespace llvm {
30  class RegScavenger;
31  class MachineBasicBlock;
32
33  class PEI : public MachineFunctionPass {
34  public:
35    static char ID;
36    PEI() : MachineFunctionPass(ID) {
37      initializePEIPass(*PassRegistry::getPassRegistry());
38    }
39
40    virtual void getAnalysisUsage(AnalysisUsage &AU) const;
41
42    /// runOnMachineFunction - Insert prolog/epilog code and replace abstract
43    /// frame indexes with appropriate references.
44    ///
45    bool runOnMachineFunction(MachineFunction &Fn);
46
47  private:
48    RegScavenger *RS;
49
50    // MinCSFrameIndex, MaxCSFrameIndex - Keeps the range of callee saved
51    // stack frame indexes.
52    unsigned MinCSFrameIndex, MaxCSFrameIndex;
53
54    // Entry and return blocks of the current function.
55    MachineBasicBlock* EntryBlock;
56    SmallVector<MachineBasicBlock*, 4> ReturnBlocks;
57
58    // Flag to control whether to use the register scavenger to resolve
59    // frame index materialization registers. Set according to
60    // TRI->requiresFrameIndexScavenging() for the curren function.
61    bool FrameIndexVirtualScavenging;
62
63    void calculateSets(MachineFunction &Fn);
64    void calculateCallsInformation(MachineFunction &Fn);
65    void calculateCalleeSavedRegisters(MachineFunction &Fn);
66    void insertCSRSpillsAndRestores(MachineFunction &Fn);
67    void calculateFrameObjectOffsets(MachineFunction &Fn);
68    void replaceFrameIndices(MachineFunction &Fn);
69    void replaceFrameIndices(MachineBasicBlock *BB, MachineFunction &Fn,
70                             int &SPAdj);
71    void scavengeFrameVirtualRegs(MachineFunction &Fn);
72    void insertPrologEpilogCode(MachineFunction &Fn);
73
74    // Convenience for recognizing return blocks.
75    bool isReturnBlock(MachineBasicBlock* MBB);
76  };
77} // End llvm namespace
78#endif
79