// Copyright (c) 2016 Google Inc.

//

// Licensed under the Apache License, Version 2.0 (the "License");

// you may not use this file except in compliance with the License.

// You may obtain a copy of the License at

//

//     http://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing, software

// distributed under the License is distributed on an "AS IS" BASIS,

// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

// See the License for the specific language governing permissions and

// limitations under the License.

#ifndef SOURCE_OPT_PASS_H_

#define SOURCE_OPT_PASS_H_

#include <algorithm>

#include <map>

#include <unordered_map>

#include <unordered_set>

#include <utility>

#include "source/opt/basic_block.h"

#include "source/opt/def_use_manager.h"

#include "source/opt/ir_context.h"

#include "source/opt/module.h"

#include "source/util/status.h"

#include "spirv-tools/libspirv.hpp"

#include "types.h"

// Avoid unused variable warning/error on Linux

#ifndef NDEBUG

#define USE_ASSERT(x) assert(x)

#else

#define USE_ASSERT(x) ((void)(x))

#endif

namespace spvtools {

namespace opt {

// Abstract class of a pass. All passes should implement this abstract class

// and all analysis and transformation is done via the Process() method.

class Pass {

 public:

  // The status of processing a module using a pass.

  //

  // The numbers for the cases are assigned to make sure that Failure & anything

  // is Failure, SuccessWithChange & any success is SuccessWithChange.

  using Status = utils::Status;

  using ProcessFunction = std::function<bool(Function*)>;

  // Destructs the pass.

  virtual ~Pass() = default;

  // Returns a descriptive name for this pass.

  //

  // NOTE: When deriving a new pass class, make sure you make the name

  // compatible with the corresponding spirv-opt command-line flag. For example,

  // if you add the flag --my-pass to spirv-opt, make this function return

  // "my-pass" (no leading hyphens).

  virtual const char* name() const = 0;

  // Sets the message consumer to the given |consumer|. |consumer| which will be

  // invoked every time there is a message to be communicated to the outside.

  void SetMessageConsumer(MessageConsumer c) { consumer_ = std::move(c); }

  // Returns the reference to the message consumer for this pass.

  const MessageConsumer& consumer() const { return consumer_; }

  // Returns the def-use manager used for this pass. TODO(dnovillo): This should

  // be handled by the pass manager.

  analysis::DefUseManager* get_def_use_mgr() const {

    return context()->get_def_use_mgr();

  }

  analysis::DecorationManager* get_decoration_mgr() const {

    return context()->get_decoration_mgr();

  }

  FeatureManager* get_feature_mgr() const {

    return context()->get_feature_mgr();

  }

  // Returns a pointer to the current module for this pass.

  Module* get_module() const { return context_->module(); }

  // Sets the pointer to the current context for this pass.

  void SetContextForTesting(IRContext* ctx) { context_ = ctx; }

  // Returns a pointer to the current context for this pass.

  IRContext* context() const { return context_; }

  // Returns a pointer to the CFG for current module.

  CFG* cfg() const { return context()->cfg(); }

  // Run the pass on the given |module|. Returns Status::Failure if errors occur

  // when processing. Returns the corresponding Status::Success if processing is

  // successful to indicate whether changes are made to the module.  If there

  // were any changes it will also invalidate the analyses in the IRContext

  // that are not preserved.

  //

  // It is an error if |Run| is called twice with the same instance of the pass.

  // If this happens the return value will be |Failure|.

  Status Run(IRContext* ctx);

  // Returns the set of analyses that the pass is guaranteed to preserve.

  virtual IRContext::Analysis GetPreservedAnalyses() {

    return IRContext::kAnalysisNone;

  }

  // Return type id for |ptrInst|'s pointee

  uint32_t GetPointeeTypeId(const Instruction* ptrInst) const;

  // Return base type of |ty_id| type

  Instruction* GetBaseType(uint32_t ty_id);

  // Return true if |inst| returns scalar, vector or matrix type with base

  // float and |width|

  bool IsFloat(uint32_t ty_id, uint32_t width);

  // Return the id of OpConstantNull of type |type_id|. Create if necessary.

  uint32_t GetNullId(uint32_t type_id);

 protected:

  // Constructs a new pass.

  //

  // The constructed instance will have an empty message consumer, which just

  // ignores all messages from the library. Use SetMessageConsumer() to supply

  // one if messages are of concern.

  Pass();

  // Processes the given |module|. Returns Status::Failure if errors occur when

  // processing. Returns the corresponding Status::Success if processing is

  // successful to indicate whether changes are made to the module.

  virtual Status Process() = 0;

  // Return the next available SSA id and increment it.

  // TODO(1841): Handle id overflow.

  uint32_t TakeNextId() { return context_->TakeNextId(); }

  // Returns the id whose value is the same as |object_to_copy| except its type

  // is |new_type_id|.  Any instructions needed to generate this value will be

  // inserted before |insertion_position|. Returns 0 if a copy could not be

  // done.

  uint32_t GenerateCopy(Instruction* object_to_copy, uint32_t new_type_id,

                        Instruction* insertion_position);

 private:

  MessageConsumer consumer_;  // Message consumer.

  // The context that this pass belongs to.

  IRContext* context_;

  // An instance of a pass can only be run once because it is too hard to

  // enforce proper resetting of internal state for each instance.  This member

  // is used to check that we do not run the same instance twice.

  bool already_run_;

};

inline Pass::Status CombineStatus(Pass::Status a, Pass::Status b) {

  return std::min(a, b);

}

}  // namespace opt

}  // namespace spvtools

#endif  // SOURCE_OPT_PASS_H_