SPIRV-Tools/source/opt/def_use_manager.h
Alan Baker 6587d3f8a3 Adding early exit versions of several ForEach* methods
* Looked through code for instances where code would benefit from early
exit
 * Added a corresponding WhileEach* method and updated the code
2018-01-12 17:05:09 -05:00

252 lines
10 KiB
C++

// 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 LIBSPIRV_OPT_DEF_USE_MANAGER_H_
#define LIBSPIRV_OPT_DEF_USE_MANAGER_H_
#include <list>
#include <set>
#include <unordered_map>
#include <vector>
#include "instruction.h"
#include "module.h"
#include "spirv-tools/libspirv.hpp"
namespace spvtools {
namespace opt {
namespace analysis {
// Class for representing a use of id. Note that:
// * Result type id is a use.
// * Ids referenced in OpSectionMerge & OpLoopMerge are considered as use.
// * Ids referenced in OpPhi's in operands are considered as use.
struct Use {
ir::Instruction* inst; // Instruction using the id.
uint32_t operand_index; // logical operand index of the id use. This can be
// the index of result type id.
};
inline bool operator==(const Use& lhs, const Use& rhs) {
return lhs.inst == rhs.inst && lhs.operand_index == rhs.operand_index;
}
inline bool operator!=(const Use& lhs, const Use& rhs) { return !(lhs == rhs); }
inline bool operator<(const Use& lhs, const Use& rhs) {
if (lhs.inst < rhs.inst) return true;
if (lhs.inst > rhs.inst) return false;
return lhs.operand_index < rhs.operand_index;
}
// Definition and user pair.
//
// The first element of the pair is the definition.
// The second element of the pair is the user.
//
// Definition should never be null. User can be null, however, such an entry
// should be used only for searching (e.g. all users of a particular definition)
// and never stored in a container.
using UserEntry = std::pair<ir::Instruction*, ir::Instruction*>;
// Orders UserEntry for use in associative containers (i.e. less than ordering).
//
// The definition of an UserEntry is treated as the major key and the users as
// the minor key so that all the users of a particular definition are
// consecutive in a container.
//
// A null user always compares less than a real user. This is done to provide
// easy values to search for the beginning of the users of a particular
// definition (i.e. using {def, nullptr}).
struct UserEntryLess {
bool operator()(const UserEntry& lhs, const UserEntry& rhs) const {
// If lhs.first and rhs.first are both null, fall through to checking the
// second entries.
if (!lhs.first && rhs.first) return true;
if (lhs.first && !rhs.first) return false;
// If neither definition is null, then compare unique ids.
if (lhs.first && rhs.first) {
if (lhs.first->unique_id() < rhs.first->unique_id()) return true;
if (rhs.first->unique_id() < lhs.first->unique_id()) return false;
}
// Return false on equality.
if (!lhs.second && !rhs.second) return false;
if (!lhs.second) return true;
if (!rhs.second) return false;
// If neither user is null then compare unique ids.
return lhs.second->unique_id() < rhs.second->unique_id();
}
};
// A class for analyzing and managing defs and uses in an ir::Module.
class DefUseManager {
public:
using IdToDefMap = std::unordered_map<uint32_t, ir::Instruction*>;
using IdToUsersMap = std::set<UserEntry, UserEntryLess>;
// Constructs a def-use manager from the given |module|. All internal messages
// will be communicated to the outside via the given message |consumer|. This
// instance only keeps a reference to the |consumer|, so the |consumer| should
// outlive this instance.
DefUseManager(ir::Module* module) { AnalyzeDefUse(module); }
DefUseManager(const DefUseManager&) = delete;
DefUseManager(DefUseManager&&) = delete;
DefUseManager& operator=(const DefUseManager&) = delete;
DefUseManager& operator=(DefUseManager&&) = delete;
// Analyzes the defs in the given |inst|.
void AnalyzeInstDef(ir::Instruction* inst);
// Analyzes the uses in the given |inst|.
//
// All operands of |inst| must be analyzed as defs.
void AnalyzeInstUse(ir::Instruction* inst);
// Analyzes the defs and uses in the given |inst|.
void AnalyzeInstDefUse(ir::Instruction* inst);
// Returns the def instruction for the given |id|. If there is no instruction
// defining |id|, returns nullptr.
ir::Instruction* GetDef(uint32_t id);
const ir::Instruction* GetDef(uint32_t id) const;
// Runs the given function |f| on each unique user instruction of |def| (or
// |id|).
//
// If one instruction uses |def| in multiple operands, that instruction will
// only be visited once.
//
// |def| (or |id|) must be registered as a definition.
void ForEachUser(const ir::Instruction* def,
const std::function<void(ir::Instruction*)>& f) const;
void ForEachUser(uint32_t id,
const std::function<void(ir::Instruction*)>& f) const;
// Runs the given function |f| on each unique user instruction of |def| (or
// |id|). If |f| returns false, iteration is terminated and this function
// returns false.
//
// If one instruction uses |def| in multiple operands, that instruction will
// be only be visited once.
//
// |def| (or |id|) must be registered as a definition.
bool WhileEachUser(const ir::Instruction* def,
const std::function<bool(ir::Instruction*)>& f) const;
bool WhileEachUser(uint32_t id,
const std::function<bool(ir::Instruction*)>& f) const;
// Runs the given function |f| on each unique use of |def| (or
// |id|).
//
// If one instruction uses |def| in multiple operands, each operand will be
// visited separately.
//
// |def| (or |id|) must be registered as a definition.
void ForEachUse(const ir::Instruction* def,
const std::function<void(ir::Instruction*,
uint32_t operand_index)>& f) const;
void ForEachUse(uint32_t id,
const std::function<void(ir::Instruction*,
uint32_t operand_index)>& f) const;
// Runs the given function |f| on each unique use of |def| (or
// |id|). If |f| returns false, iteration is terminated and this function
// returns false.
//
// If one instruction uses |def| in multiple operands, each operand will be
// visited separately.
//
// |def| (or |id|) must be registered as a definition.
bool WhileEachUse(const ir::Instruction* def,
const std::function<bool(ir::Instruction*,
uint32_t operand_index)>& f) const;
bool WhileEachUse(uint32_t id,
const std::function<bool(ir::Instruction*,
uint32_t operand_index)>& f) const;
// Returns the number of users of |def| (or |id|).
uint32_t NumUsers(const ir::Instruction* def) const;
uint32_t NumUsers(uint32_t id) const;
// Returns the number of uses of |def| (or |id|).
uint32_t NumUses(const ir::Instruction* def) const;
uint32_t NumUses(uint32_t id) const;
// Returns the annotation instrunctions which are a direct use of the given
// |id|. This means when the decorations are applied through decoration
// group(s), this function will just return the OpGroupDecorate
// instrcution(s) which refer to the given id as an operand. The OpDecorate
// instructions which decorate the decoration group will not be returned.
std::vector<ir::Instruction*> GetAnnotations(uint32_t id) const;
// Returns the map from ids to their def instructions.
const IdToDefMap& id_to_defs() const { return id_to_def_; }
// Returns the map from instructions to their users.
const IdToUsersMap& id_to_users() const { return id_to_users_; }
// Clear the internal def-use record of the given instruction |inst|. This
// method will update the use information of the operand ids of |inst|. The
// record: |inst| uses an |id|, will be removed from the use records of |id|.
// If |inst| defines an result id, the use record of this result id will also
// be removed. Does nothing if |inst| was not analyzed before.
void ClearInst(ir::Instruction* inst);
// Erases the records that a given instruction uses its operand ids.
void EraseUseRecordsOfOperandIds(const ir::Instruction* inst);
friend bool operator==(const DefUseManager&, const DefUseManager&);
friend bool operator!=(const DefUseManager& lhs, const DefUseManager& rhs) {
return !(lhs == rhs);
}
private:
using InstToUsedIdsMap =
std::unordered_map<const ir::Instruction*, std::vector<uint32_t>>;
// Returns the first location that {|def|, nullptr} could be inserted into the
// users map without violating ordering.
IdToUsersMap::const_iterator UsersBegin(const ir::Instruction* def) const;
// Returns true if |iter| has not reached the end of |def|'s users.
//
// In the first version |iter| is compared against the end of the map for
// validity before other checks. In the second version, |iter| is compared
// against |cached_end| for validity before other checks. This allows caching
// the map's end which is a performance improvement on some platforms.
bool UsersNotEnd(const IdToUsersMap::const_iterator& iter,
const ir::Instruction* def) const;
bool UsersNotEnd(const IdToUsersMap::const_iterator& iter,
const IdToUsersMap::const_iterator& cached_end,
const ir::Instruction* def) const;
// Analyzes the defs and uses in the given |module| and populates data
// structures in this class. Does nothing if |module| is nullptr.
void AnalyzeDefUse(ir::Module* module);
IdToDefMap id_to_def_; // Mapping from ids to their definitions
IdToUsersMap id_to_users_; // Mapping from ids to their users
// Mapping from instructions to the ids used in the instruction.
InstToUsedIdsMap inst_to_used_ids_;
};
} // namespace analysis
} // namespace opt
} // namespace spvtools
#endif // LIBSPIRV_OPT_DEF_USE_MANAGER_H_