//===-- Passes.h - Target independent code generation passes ----*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines interfaces to access the target independent code generation
// passes provided by the LLVM backend.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_CODEGEN_PASSES_H
#define LLVM_CODEGEN_PASSES_H

#include "llvm/Target/TargetMachine.h"
#include <string>

namespace llvm {

  class FunctionPass;
  class MachineFunctionPass;
  class PassInfo;
  class TargetLowering;
  class RegisterCoalescer;
  class raw_ostream;

  /// createUnreachableBlockEliminationPass - The LLVM code generator does not
  /// work well with unreachable basic blocks (what live ranges make sense for a
  /// block that cannot be reached?).  As such, a code generator should either
  /// not instruction select unreachable blocks, or it can run this pass as it's
  /// last LLVM modifying pass to clean up blocks that are not reachable from
  /// the entry block.
  FunctionPass *createUnreachableBlockEliminationPass();

  /// MachineFunctionPrinter pass - This pass prints out the machine function to
  /// the given stream, as a debugging tool.
  MachineFunctionPass *
  createMachineFunctionPrinterPass(raw_ostream &OS,
                                   const std::string &Banner ="");

  /// MachineLoopInfo pass - This pass is a loop analysis pass.
  /// 
  extern const PassInfo *const MachineLoopInfoID;

  /// MachineDominators pass - This pass is a machine dominators analysis pass.
  /// 
  extern const PassInfo *const MachineDominatorsID;

  /// PHIElimination pass - This pass eliminates machine instruction PHI nodes
  /// by inserting copy instructions.  This destroys SSA information, but is the
  /// desired input for some register allocators.  This pass is "required" by
  /// these register allocator like this: AU.addRequiredID(PHIEliminationID);
  ///
  extern const PassInfo *const PHIEliminationID;
  
  /// StrongPHIElimination pass - This pass eliminates machine instruction PHI
  /// nodes by inserting copy instructions.  This destroys SSA information, but
  /// is the desired input for some register allocators.  This pass is
  /// "required" by these register allocator like this:
  ///    AU.addRequiredID(PHIEliminationID);
  ///  This pass is still in development
  extern const PassInfo *const StrongPHIEliminationID;

  extern const PassInfo *const PreAllocSplittingID;

  /// SimpleRegisterCoalescing pass.  Aggressively coalesces every register
  /// copy it can.
  ///
  extern const PassInfo *const SimpleRegisterCoalescingID;

  /// TwoAddressInstruction pass - This pass reduces two-address instructions to
  /// use two operands. This destroys SSA information but it is desired by
  /// register allocators.
  extern const PassInfo *const TwoAddressInstructionPassID;

  /// UnreachableMachineBlockElimination pass - This pass removes unreachable
  /// machine basic blocks.
  extern const PassInfo *const UnreachableMachineBlockElimID;

  /// DeadMachineInstructionElim pass - This pass removes dead machine
  /// instructions.
  ///
  FunctionPass *createDeadMachineInstructionElimPass();

  /// Creates a register allocator as the user specified on the command line, or
  /// picks one that matches OptLevel.
  ///
  FunctionPass *createRegisterAllocator(CodeGenOpt::Level OptLevel);

  /// FastRegisterAllocation Pass - This pass register allocates as fast as
  /// possible. It is best suited for debug code where live ranges are short.
  ///
  FunctionPass *createFastRegisterAllocator();

  /// LinearScanRegisterAllocation Pass - This pass implements the linear scan
  /// register allocation algorithm, a global register allocator.
  ///
  FunctionPass *createLinearScanRegisterAllocator();

  /// PBQPRegisterAllocation Pass - This pass implements the Partitioned Boolean
  /// Quadratic Prograaming (PBQP) based register allocator.
  ///
  FunctionPass *createPBQPRegisterAllocator();

  /// SimpleRegisterCoalescing Pass - Coalesce all copies possible.  Can run
  /// independently of the register allocator.
  ///
  RegisterCoalescer *createSimpleRegisterCoalescer();

  /// PrologEpilogCodeInserter Pass - This pass inserts prolog and epilog code,
  /// and eliminates abstract frame references.
  ///
  FunctionPass *createPrologEpilogCodeInserter();
  
  /// LowerSubregs Pass - This pass lowers subregs to register-register copies
  /// which yields suboptimal, but correct code if the register allocator
  /// cannot coalesce all subreg operations during allocation.
  ///
  FunctionPass *createLowerSubregsPass();

  /// createPostRAScheduler - This pass performs post register allocation
  /// scheduling.
  FunctionPass *createPostRAScheduler(CodeGenOpt::Level OptLevel);

  /// BranchFolding Pass - This pass performs machine code CFG based
  /// optimizations to delete branches to branches, eliminate branches to
  /// successor blocks (creating fall throughs), and eliminating branches over
  /// branches.
  FunctionPass *createBranchFoldingPass(bool DefaultEnableTailMerge);

  /// TailDuplicate Pass - Duplicate blocks with unconditional branches
  /// into tails of their predecessors.
  FunctionPass *createTailDuplicatePass(bool PreRegAlloc = false);

  /// IfConverter Pass - This pass performs machine code if conversion.
  FunctionPass *createIfConverterPass();

  /// Code Placement Pass - This pass optimize code placement and aligns loop
  /// headers to target specific alignment boundary.
  FunctionPass *createCodePlacementOptPass();

  /// IntrinsicLowering Pass - Performs target-independent LLVM IR
  /// transformations for highly portable strategies.
  FunctionPass *createGCLoweringPass();
  
  /// MachineCodeAnalysis Pass - Target-independent pass to mark safe points in
  /// machine code. Must be added very late during code generation, just prior
  /// to output, and importantly after all CFG transformations (such as branch
  /// folding).
  FunctionPass *createGCMachineCodeAnalysisPass();
  
  /// Deleter Pass - Releases GC metadata.
  /// 
  FunctionPass *createGCInfoDeleter();
  
  /// Creates a pass to print GC metadata.
  /// 
  FunctionPass *createGCInfoPrinter(raw_ostream &OS);
  
  /// createMachineCSEPass - This pass performs global CSE on machine
  /// instructions.
  FunctionPass *createMachineCSEPass();

  /// createMachineLICMPass - This pass performs LICM on machine instructions.
  /// 
  FunctionPass *createMachineLICMPass(bool PreRegAlloc = true);

  /// createMachineSinkingPass - This pass performs sinking on machine
  /// instructions.
  FunctionPass *createMachineSinkingPass();

  /// createOptimizeExtsPass - This pass performs sign / zero extension
  /// optimization by increasing uses of extended values.
  FunctionPass *createOptimizeExtsPass();

  /// createOptimizePHIsPass - This pass optimizes machine instruction PHIs
  /// to take advantage of opportunities created during DAG legalization.
  FunctionPass *createOptimizePHIsPass();

  /// createStackSlotColoringPass - This pass performs stack slot coloring.
  FunctionPass *createStackSlotColoringPass(bool);

  /// createStackProtectorPass - This pass adds stack protectors to functions.
  FunctionPass *createStackProtectorPass(const TargetLowering *tli);

  /// createMachineVerifierPass - This pass verifies cenerated machine code
  /// instructions for correctness.
  ///
  /// @param allowDoubleDefs ignore double definitions of
  ///        registers. Useful before LiveVariables has run.
  FunctionPass *createMachineVerifierPass(bool allowDoubleDefs);

  /// createDwarfEHPass - This pass mulches exception handling code into a form
  /// adapted to code generation.  Required if using dwarf exception handling.
  FunctionPass *createDwarfEHPass(const TargetMachine *tm, bool fast);

  /// createSjLjEHPass - This pass adapts exception handling code to use
  /// the GCC-style builtin setjmp/longjmp (sjlj) to handling EH control flow.
  FunctionPass *createSjLjEHPass(const TargetLowering *tli);

} // End llvm namespace

#endif