// Copyright (c) 2017 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_IR_CONTEXT_H_

#define SOURCE_OPT_IR_CONTEXT_H_

#include <algorithm>

#include <iostream>

#include <limits>

#include <map>

#include <memory>

#include <queue>

#include <unordered_map>

#include <unordered_set>

#include <utility>

#include <vector>

#include "source/assembly_grammar.h"

#include "source/enum_string_mapping.h"

#include "source/opt/cfg.h"

#include "source/opt/constants.h"

#include "source/opt/debug_info_manager.h"

#include "source/opt/decoration_manager.h"

#include "source/opt/def_use_manager.h"

#include "source/opt/dominator_analysis.h"

#include "source/opt/feature_manager.h"

#include "source/opt/fold.h"

#include "source/opt/liveness.h"

#include "source/opt/loop_descriptor.h"

#include "source/opt/module.h"

#include "source/opt/register_pressure.h"

#include "source/opt/scalar_analysis.h"

#include "source/opt/struct_cfg_analysis.h"

#include "source/opt/type_manager.h"

#include "source/opt/value_number_table.h"

#include "source/util/make_unique.h"

#include "source/util/string_utils.h"

namespace spvtools {

namespace opt {

class IRContext {

 public:

  // Available analyses.

  //

  // When adding a new analysis:

  //

  // 1. Enum values should be powers of 2. These are cast into uint32_t

  //    bitmasks, so we can have at most 31 analyses represented.

  //

  // 2. Make sure it gets invalidated or preserved by IRContext methods that add

  //    or remove IR elements (e.g., KillDef, KillInst, ReplaceAllUsesWith).

  //

  // 3. Add handling code in BuildInvalidAnalyses and InvalidateAnalyses

  enum Analysis {

    kAnalysisNone = 0 << 0,

    kAnalysisBegin = 1 << 0,

    kAnalysisDefUse = kAnalysisBegin,

    kAnalysisInstrToBlockMapping = 1 << 1,

    kAnalysisDecorations = 1 << 2,

    kAnalysisCombinators = 1 << 3,

    kAnalysisCFG = 1 << 4,

    kAnalysisDominatorAnalysis = 1 << 5,

    kAnalysisLoopAnalysis = 1 << 6,

    kAnalysisNameMap = 1 << 7,

    kAnalysisScalarEvolution = 1 << 8,

    kAnalysisRegisterPressure = 1 << 9,

    kAnalysisValueNumberTable = 1 << 10,

    kAnalysisStructuredCFG = 1 << 11,

    kAnalysisBuiltinVarId = 1 << 12,

    kAnalysisIdToFuncMapping = 1 << 13,

    kAnalysisConstants = 1 << 14,

    kAnalysisTypes = 1 << 15,

    kAnalysisDebugInfo = 1 << 16,

    kAnalysisLiveness = 1 << 17,

    kAnalysisEnd = 1 << 18

  };

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

  friend inline Analysis operator|(Analysis lhs, Analysis rhs);

  friend inline Analysis& operator|=(Analysis& lhs, Analysis rhs);

  friend inline Analysis operator<<(Analysis a, int shift);

  friend inline Analysis& operator<<=(Analysis& a, int shift);

  // Creates an |IRContext| that contains an owned |Module|

  IRContext(spv_target_env env, MessageConsumer c)

      : syntax_context_(spvContextCreate(env)),

        grammar_(syntax_context_),

        unique_id_(0),

        module_(new Module()),

        consumer_(std::move(c)),

        def_use_mgr_(nullptr),

        feature_mgr_(nullptr),

        valid_analyses_(kAnalysisNone),

        constant_mgr_(nullptr),

        type_mgr_(nullptr),

        id_to_name_(nullptr),

        max_id_bound_(kDefaultMaxIdBound),

        preserve_bindings_(false),

        preserve_spec_constants_(false) {

    SetContextMessageConsumer(syntax_context_, consumer_);

    module_->SetContext(this);

  }

  IRContext(spv_target_env env, std::unique_ptr<Module>&& m, MessageConsumer c)

      : syntax_context_(spvContextCreate(env)),

        grammar_(syntax_context_),

        unique_id_(0),

        module_(std::move(m)),

        consumer_(std::move(c)),

        def_use_mgr_(nullptr),

        feature_mgr_(nullptr),

        valid_analyses_(kAnalysisNone),

        type_mgr_(nullptr),

        id_to_name_(nullptr),

        max_id_bound_(kDefaultMaxIdBound),

        preserve_bindings_(false),

        preserve_spec_constants_(false) {

    SetContextMessageConsumer(syntax_context_, consumer_);

    module_->SetContext(this);

    InitializeCombinators();

  }

  ~IRContext() { spvContextDestroy(syntax_context_); }

  Module* module() const { return module_.get(); }

  // Returns a vector of pointers to constant-creation instructions in this

  // context.

  inline std::vector<Instruction*> GetConstants();

  inline std::vector<const Instruction*> GetConstants() const;

  // Iterators for annotation instructions contained in this context.

  inline Module::inst_iterator annotation_begin();

  inline Module::inst_iterator annotation_end();

  inline IteratorRange<Module::inst_iterator> annotations();

  inline IteratorRange<Module::const_inst_iterator> annotations() const;

  // Iterators for capabilities instructions contained in this module.

  inline Module::inst_iterator capability_begin();

  inline Module::inst_iterator capability_end();

  inline IteratorRange<Module::inst_iterator> capabilities();

  inline IteratorRange<Module::const_inst_iterator> capabilities() const;

  // Iterators for extensions instructions contained in this module.

  inline Module::inst_iterator extension_begin();

  inline Module::inst_iterator extension_end();

  inline IteratorRange<Module::inst_iterator> extensions();

  inline IteratorRange<Module::const_inst_iterator> extensions() const;

  // Iterators for types, constants and global variables instructions.

  inline Module::inst_iterator types_values_begin();

  inline Module::inst_iterator types_values_end();

  inline IteratorRange<Module::inst_iterator> types_values();

  inline IteratorRange<Module::const_inst_iterator> types_values() const;

  // Iterators for ext_inst import instructions contained in this module.

  inline Module::inst_iterator ext_inst_import_begin();

  inline Module::inst_iterator ext_inst_import_end();

  inline IteratorRange<Module::inst_iterator> ext_inst_imports();

  inline IteratorRange<Module::const_inst_iterator> ext_inst_imports() const;

  // There are several kinds of debug instructions, according to where they can

  // appear in the logical layout of a module:

  //  - Section 7a:  OpString, OpSourceExtension, OpSource, OpSourceContinued

  //  - Section 7b:  OpName, OpMemberName

  //  - Section 7c:  OpModuleProcessed

  //  - Mostly anywhere: OpLine and OpNoLine

  //

  // Iterators for debug 1 instructions (excluding OpLine & OpNoLine) contained

  // in this module.  These are for layout section 7a.

  inline Module::inst_iterator debug1_begin();

  inline Module::inst_iterator debug1_end();

  inline IteratorRange<Module::inst_iterator> debugs1();

  inline IteratorRange<Module::const_inst_iterator> debugs1() const;

  // Iterators for debug 2 instructions (excluding OpLine & OpNoLine) contained

  // in this module.  These are for layout section 7b.

  inline Module::inst_iterator debug2_begin();

  inline Module::inst_iterator debug2_end();

  inline IteratorRange<Module::inst_iterator> debugs2();

  inline IteratorRange<Module::const_inst_iterator> debugs2() const;

  // Iterators for debug 3 instructions (excluding OpLine & OpNoLine) contained

  // in this module.  These are for layout section 7c.

  inline Module::inst_iterator debug3_begin();

  inline Module::inst_iterator debug3_end();

  inline IteratorRange<Module::inst_iterator> debugs3();

  inline IteratorRange<Module::const_inst_iterator> debugs3() const;

  // Iterators for debug info instructions (excluding OpLine & OpNoLine)

  // contained in this module.  These are OpExtInst &

  // OpExtInstWithForwardRefsKHR for DebugInfo extension placed between section

  // 9 and 10.

  inline Module::inst_iterator ext_inst_debuginfo_begin();

  inline Module::inst_iterator ext_inst_debuginfo_end();

  inline IteratorRange<Module::inst_iterator> ext_inst_debuginfo();

  inline IteratorRange<Module::const_inst_iterator> ext_inst_debuginfo() const;

  // Add |capability| to the module, if it is not already enabled.

  inline void AddCapability(spv::Capability capability);

  // Appends a capability instruction to this module.

  inline void AddCapability(std::unique_ptr<Instruction>&& c);

  // Removes instruction declaring `capability` from this module.

  // Returns true if the capability was removed, false otherwise.

  bool RemoveCapability(spv::Capability capability);

  // Appends an extension instruction to this module.

  inline void AddExtension(const std::string& ext_name);

  inline void AddExtension(std::unique_ptr<Instruction>&& e);

  // Removes instruction declaring `extension` from this module.

  // Returns true if the extension was removed, false otherwise.

  bool RemoveExtension(Extension extension);

  // Appends an extended instruction set instruction to this module.

  inline void AddExtInstImport(const std::string& name);

  inline void AddExtInstImport(std::unique_ptr<Instruction>&& e);

  // Set the memory model for this module.

  inline void SetMemoryModel(std::unique_ptr<Instruction>&& m);

  // Get the memory model for this module.

  inline const Instruction* GetMemoryModel() const;

  // Appends an entry point instruction to this module.

  inline void AddEntryPoint(std::unique_ptr<Instruction>&& e);

  // Appends an execution mode instruction to this module.

  inline void AddExecutionMode(std::unique_ptr<Instruction>&& e);

  // Appends a debug 1 instruction (excluding OpLine & OpNoLine) to this module.

  // "debug 1" instructions are the ones in layout section 7.a), see section

  // 2.4 Logical Layout of a Module from the SPIR-V specification.

  inline void AddDebug1Inst(std::unique_ptr<Instruction>&& d);

  // Appends a debug 2 instruction (excluding OpLine & OpNoLine) to this module.

  // "debug 2" instructions are the ones in layout section 7.b), see section

  // 2.4 Logical Layout of a Module from the SPIR-V specification.

  inline void AddDebug2Inst(std::unique_ptr<Instruction>&& d);

  // Appends a debug 3 instruction (OpModuleProcessed) to this module.

  // This is due to decision by the SPIR Working Group, pending publication.

  inline void AddDebug3Inst(std::unique_ptr<Instruction>&& d);

  // Appends a OpExtInst for DebugInfo to this module.

  inline void AddExtInstDebugInfo(std::unique_ptr<Instruction>&& d);

  // Appends an annotation instruction to this module.

  inline void AddAnnotationInst(std::unique_ptr<Instruction>&& a);

  // Appends a type-declaration instruction to this module.

  inline void AddType(std::unique_ptr<Instruction>&& t);

  // Appends a constant, global variable, or OpUndef instruction to this module.

  inline void AddGlobalValue(std::unique_ptr<Instruction>&& v);

  // Prepends a function declaration to this module.

  inline void AddFunctionDeclaration(std::unique_ptr<Function>&& f);

  // Appends a function to this module.

  inline void AddFunction(std::unique_ptr<Function>&& f);

  // Returns a pointer to a def-use manager.  If the def-use manager is

  // invalid, it is rebuilt first.

  analysis::DefUseManager* get_def_use_mgr() {

    if (!AreAnalysesValid(kAnalysisDefUse)) {

      BuildDefUseManager();

    }

    return def_use_mgr_.get();

  }

  // Returns a pointer to a liveness manager.  If the liveness manager is

  // invalid, it is rebuilt first.

  analysis::LivenessManager* get_liveness_mgr() {

    if (!AreAnalysesValid(kAnalysisLiveness)) {

      BuildLivenessManager();

    }

    return liveness_mgr_.get();

  }

  // Returns a pointer to a value number table.  If the liveness analysis is

  // invalid, it is rebuilt first.

  ValueNumberTable* GetValueNumberTable() {

    if (!AreAnalysesValid(kAnalysisValueNumberTable)) {

      BuildValueNumberTable();

    }

    return vn_table_.get();

  }

  // Returns a pointer to a StructuredCFGAnalysis.  If the analysis is invalid,

  // it is rebuilt first.

  StructuredCFGAnalysis* GetStructuredCFGAnalysis() {

    if (!AreAnalysesValid(kAnalysisStructuredCFG)) {

      BuildStructuredCFGAnalysis();

    }

    return struct_cfg_analysis_.get();

  }

  // Returns a pointer to a liveness analysis.  If the liveness analysis is

  // invalid, it is rebuilt first.

  LivenessAnalysis* GetLivenessAnalysis() {

    if (!AreAnalysesValid(kAnalysisRegisterPressure)) {

      BuildRegPressureAnalysis();

    }

    return reg_pressure_.get();

  }

  // Returns the basic block for instruction |instr|. Re-builds the instruction

  // block map, if needed.

  BasicBlock* get_instr_block(Instruction* instr) {

    if (!AreAnalysesValid(kAnalysisInstrToBlockMapping)) {

      BuildInstrToBlockMapping();

    }

    auto entry = instr_to_block_.find(instr);

    return (entry != instr_to_block_.end()) ? entry->second : nullptr;

  }

  // Returns the basic block for |id|. Re-builds the instruction block map, if

  // needed.

  //

  // |id| must be a registered definition.

  BasicBlock* get_instr_block(uint32_t id) {

    Instruction* def = get_def_use_mgr()->GetDef(id);

    return get_instr_block(def);

  }

  // Sets the basic block for |inst|. Re-builds the mapping if it has become

  // invalid.

  void set_instr_block(Instruction* inst, BasicBlock* block) {

    if (AreAnalysesValid(kAnalysisInstrToBlockMapping)) {

      instr_to_block_[inst] = block;

    }

  }

  // Returns a pointer the decoration manager.  If the decoration manager is

  // invalid, it is rebuilt first.

  analysis::DecorationManager* get_decoration_mgr() {

    if (!AreAnalysesValid(kAnalysisDecorations)) {

      BuildDecorationManager();

    }

    return decoration_mgr_.get();

  }

  // Returns a pointer to the constant manager.  If no constant manager has been

  // created yet, it creates one.  NOTE: Once created, the constant manager

  // remains active and it is never re-built.

  analysis::ConstantManager* get_constant_mgr() {

    if (!AreAnalysesValid(kAnalysisConstants)) {

      BuildConstantManager();

    }

    return constant_mgr_.get();

  }

  // Returns a pointer to the type manager.  If no type manager has been created

  // yet, it creates one. NOTE: Once created, the type manager remains active it

  // is never re-built.

  analysis::TypeManager* get_type_mgr() {

    if (!AreAnalysesValid(kAnalysisTypes)) {

      BuildTypeManager();

    }

    return type_mgr_.get();

  }

  // Returns a pointer to the debug information manager.  If no debug

  // information manager has been created yet, it creates one.

  // NOTE: Once created, the debug information manager remains active

  // it is never re-built.

  analysis::DebugInfoManager* get_debug_info_mgr() {

    if (!AreAnalysesValid(kAnalysisDebugInfo)) {

      BuildDebugInfoManager();

    }

    return debug_info_mgr_.get();

  }

  // Returns a pointer to the scalar evolution analysis. If it is invalid it

  // will be rebuilt first.

  ScalarEvolutionAnalysis* GetScalarEvolutionAnalysis() {

    if (!AreAnalysesValid(kAnalysisScalarEvolution)) {

      BuildScalarEvolutionAnalysis();

    }

    return scalar_evolution_analysis_.get();

  }

  // Build the map from the ids to the OpName and OpMemberName instruction

  // associated with it.

  inline void BuildIdToNameMap();

  // Returns a range of instrucions that contain all of the OpName and

  // OpMemberNames associated with the given id.

  inline IteratorRange<std::multimap<uint32_t, Instruction*>::iterator>

  GetNames(uint32_t id);

  // Returns an OpMemberName instruction that targets |struct_type_id| at

  // index |index|. Returns nullptr if no such instruction exists.

  // While the SPIR-V spec does not prohibit having multiple OpMemberName

  // instructions for the same structure member, it is hard to imagine a member

  // having more than one name. This method returns the first one it finds.

  inline Instruction* GetMemberName(uint32_t struct_type_id, uint32_t index);

  // Copy names from |old_id| to |new_id|. Only copy member name if index is

  // less than |max_member_index|.

  inline void CloneNames(const uint32_t old_id, const uint32_t new_id,

                         const uint32_t max_member_index = UINT32_MAX);

  // 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_; }

  // Rebuilds the analyses in |set| that are invalid.

  void BuildInvalidAnalyses(Analysis set);

  // Invalidates all of the analyses except for those in |preserved_analyses|.

  void InvalidateAnalysesExceptFor(Analysis preserved_analyses);

  // Invalidates the analyses marked in |analyses_to_invalidate|.

  void InvalidateAnalyses(Analysis analyses_to_invalidate);

  // Deletes the instruction defining the given |id|. Returns true on

  // success, false if the given |id| is not defined at all. This method also

  // erases the name, decorations, and definition of |id|.

  //

  // Pointers and iterators pointing to the deleted instructions become invalid.

  // However other pointers and iterators are still valid.

  bool KillDef(uint32_t id);

  // Deletes the given instruction |inst|. This method erases the

  // information of the given instruction's uses of its operands. If |inst|

  // defines a result id, its name and decorations will also be deleted.

  //

  // Pointer and iterator pointing to the deleted instructions become invalid.

  // However other pointers and iterators are still valid.

  //

  // Note that if an instruction is not in an instruction list, the memory may

  // not be safe to delete, so the instruction is turned into a OpNop instead.

  // This can happen with OpLabel.

  //

  // Returns a pointer to the instruction after |inst| or |nullptr| if no such

  // instruction exists.

  Instruction* KillInst(Instruction* inst);

  // Deletes all the instruction in the range [`begin`; `end`[, for which the

  // unary predicate `condition` returned true.

  // Returns true if at least one instruction was removed, false otherwise.

  //

  // Pointer and iterator pointing to the deleted instructions become invalid.

  // However other pointers and iterators are still valid.

  bool KillInstructionIf(Module::inst_iterator begin, Module::inst_iterator end,

                         std::function<bool(Instruction*)> condition);

  // Collects the non-semantic instruction tree that uses |inst|'s result id

  // to be killed later.

  void CollectNonSemanticTree(Instruction* inst,

                              std::unordered_set<Instruction*>* to_kill);

  // Collect function reachable from |entryId|, returns |funcs|

  void CollectCallTreeFromRoots(unsigned entryId,

                                std::unordered_set<uint32_t>* funcs);

  // Returns true if all of the given analyses are valid.

  bool AreAnalysesValid(Analysis set) { return (set & valid_analyses_) == set; }

  // Replaces all uses of |before| id with |after| id. Returns true if any

  // replacement happens. This method does not kill the definition of the

  // |before| id. If |after| is the same as |before|, does nothing and returns

  // false.

  //

  // |before| and |after| must be registered definitions in the DefUseManager.

  bool ReplaceAllUsesWith(uint32_t before, uint32_t after);

  // Replace all uses of |before| id with |after| id if those uses

  // (instruction) return true for |predicate|. Returns true if

  // any replacement happens. This method does not kill the definition of the

  // |before| id. If |after| is the same as |before|, does nothing and return

  // false.

  bool ReplaceAllUsesWithPredicate(

      uint32_t before, uint32_t after,

      const std::function<bool(Instruction*)>& predicate);

  // Returns true if all of the analyses that are suppose to be valid are

  // actually valid.

  bool IsConsistent();

  // The IRContext will look at the def and uses of |inst| and update any valid

  // analyses will be updated accordingly.

  inline void AnalyzeDefUse(Instruction* inst);

  // Informs the IRContext that the uses of |inst| are going to change, and that

  // is should forget everything it know about the current uses.  Any valid

  // analyses will be updated accordingly.

  void ForgetUses(Instruction* inst);

  // The IRContext will look at the uses of |inst| and update any valid analyses

  // will be updated accordingly.

  void AnalyzeUses(Instruction* inst);

  // Kill all name and decorate ops targeting |id|.

  void KillNamesAndDecorates(uint32_t id);

  // Kill all name and decorate ops targeting the result id of |inst|.

  void KillNamesAndDecorates(Instruction* inst);

  // Change operands of debug instruction to DebugInfoNone.

  void KillOperandFromDebugInstructions(Instruction* inst);

  // Returns the next unique id for use by an instruction.

  inline uint32_t TakeNextUniqueId() {

    assert(unique_id_ != std::numeric_limits<uint32_t>::max());

    // Skip zero.

    return ++unique_id_;

  }

  // Returns true if |inst| is a combinator in the current context.

  // |combinator_ops_| is built if it has not been already.

  inline bool IsCombinatorInstruction(const Instruction* inst) {

    if (!AreAnalysesValid(kAnalysisCombinators)) {

      InitializeCombinators();

    }

    constexpr uint32_t kExtInstSetIdInIndx = 0;

    constexpr uint32_t kExtInstInstructionInIndx = 1;

    if (inst->opcode() != spv::Op::OpExtInst) {

      return combinator_ops_[0].count(uint32_t(inst->opcode())) != 0;

    } else {

      uint32_t set = inst->GetSingleWordInOperand(kExtInstSetIdInIndx);

      auto op = inst->GetSingleWordInOperand(kExtInstInstructionInIndx);

      return combinator_ops_[set].count(op) != 0;

    }

  }

  // Returns a pointer to the CFG for all the functions in |module_|.

  CFG* cfg() {

    if (!AreAnalysesValid(kAnalysisCFG)) {

      BuildCFG();

    }

    return cfg_.get();

  }

  // Gets the loop descriptor for function |f|.

  LoopDescriptor* GetLoopDescriptor(const Function* f);

  // Gets the dominator analysis for function |f|.

  DominatorAnalysis* GetDominatorAnalysis(const Function* f);

  // Gets the postdominator analysis for function |f|.

  PostDominatorAnalysis* GetPostDominatorAnalysis(const Function* f);

  // Remove the dominator tree of |f| from the cache.

  inline void RemoveDominatorAnalysis(const Function* f) {

    dominator_trees_.erase(f);

  }

  // Remove the postdominator tree of |f| from the cache.

  inline void RemovePostDominatorAnalysis(const Function* f) {

    post_dominator_trees_.erase(f);

  }

  // Return the next available SSA id and increment it.  Returns 0 if the

  // maximum SSA id has been reached.

  inline uint32_t TakeNextId() {

    uint32_t next_id = module()->TakeNextIdBound();

    if (next_id == 0) {

      if (consumer()) {

        std::string message = "ID overflow. Try running compact-ids.";

        consumer()(SPV_MSG_ERROR, "", {0, 0, 0}, message.c_str());

      }

#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION

      // If TakeNextId returns 0, it is very likely that execution will

      // subsequently fail. Such failures are false alarms from a fuzzing point

      // of view: they are due to the fact that too many ids were used, rather

      // than being due to an actual bug. Thus, during a fuzzing build, it is

      // preferable to bail out when ID overflow occurs.

      //

      // A zero exit code is returned here because a non-zero code would cause

      // ClusterFuzz/OSS-Fuzz to regard the termination as a crash, and spurious

      // crash reports is what this guard aims to avoid.

      exit(0);

#endif

    }

    return next_id;

  }

  FeatureManager* get_feature_mgr() {

    if (!feature_mgr_.get()) {

      AnalyzeFeatures();

    }

    return feature_mgr_.get();

  }

  void ResetFeatureManager() { feature_mgr_.reset(nullptr); }

  // Returns the grammar for this context.

  const AssemblyGrammar& grammar() const { return grammar_; }

  // If |inst| has not yet been analysed by the def-use manager, then analyse

  // its definitions and uses.

  inline void UpdateDefUse(Instruction* inst);

  const InstructionFolder& get_instruction_folder() {

    if (!inst_folder_) {

      inst_folder_ = MakeUnique<InstructionFolder>(this);

    }

    return *inst_folder_;

  }

  uint32_t max_id_bound() const { return max_id_bound_; }

  void set_max_id_bound(uint32_t new_bound) { max_id_bound_ = new_bound; }

  bool preserve_bindings() const { return preserve_bindings_; }

  void set_preserve_bindings(bool should_preserve_bindings) {

    preserve_bindings_ = should_preserve_bindings;

  }

  bool preserve_spec_constants() const { return preserve_spec_constants_; }

  void set_preserve_spec_constants(bool should_preserve_spec_constants) {

    preserve_spec_constants_ = should_preserve_spec_constants;

  }

  // Return id of input variable only decorated with |builtin|, if in module.

  // Create variable and return its id otherwise. If builtin not currently

  // supported, return 0.

  uint32_t GetBuiltinInputVarId(uint32_t builtin);

  // Returns the function whose id is |id|, if one exists.  Returns |nullptr|

  // otherwise.

  Function* GetFunction(uint32_t id) {

    if (!AreAnalysesValid(kAnalysisIdToFuncMapping)) {

      BuildIdToFuncMapping();

    }

    auto entry = id_to_func_.find(id);

    return (entry != id_to_func_.end()) ? entry->second : nullptr;

  }

  Function* GetFunction(Instruction* inst) {

    if (inst->opcode() != spv::Op::OpFunction) {

      return nullptr;

    }

    return GetFunction(inst->result_id());

  }

  // Add to |todo| all ids of functions called directly from |func|.

  void AddCalls(const Function* func, std::queue<uint32_t>* todo);

  // Applies |pfn| to every function in the call trees that are rooted at the

  // entry points.  Returns true if any call |pfn| returns true.  By convention

  // |pfn| should return true if it modified the module.

  bool ProcessEntryPointCallTree(ProcessFunction& pfn);

  // Applies |pfn| to every function in the call trees rooted at the entry

  // points and exported functions.  Returns true if any call |pfn| returns

  // true.  By convention |pfn| should return true if it modified the module.

  bool ProcessReachableCallTree(ProcessFunction& pfn);

  // Applies |pfn| to every function in the call trees rooted at the elements of

  // |roots|.  Returns true if any call to |pfn| returns true.  By convention

  // |pfn| should return true if it modified the module.  After returning

  // |roots| will be empty.

  bool ProcessCallTreeFromRoots(ProcessFunction& pfn,

                                std::queue<uint32_t>* roots);

  // Emits a error message to the message consumer indicating the error

  // described by |message| occurred in |inst|.

  void EmitErrorMessage(std::string message, Instruction* inst);

  // Returns true if and only if there is a path to |bb| from the entry block of

  // the function that contains |bb|.

  bool IsReachable(const opt::BasicBlock& bb);

  // Return the stage of the module. Will generate error if entry points don't

  // all have the same stage.

  spv::ExecutionModel GetStage();

  // Returns true of the current target environment is at least that of the

  // given environment.

  bool IsTargetEnvAtLeast(spv_target_env env) {

    // A bit of a hack. We assume that the target environments are appended to

    // the enum, so that there is an appropriate order.

    return syntax_context_->target_env >= env;

  }

  // Return the target environment for the current context.

  spv_target_env GetTargetEnv() const { return syntax_context_->target_env; }

 private:

  // Builds the def-use manager from scratch, even if it was already valid.

  void BuildDefUseManager() {

    def_use_mgr_ = MakeUnique<analysis::DefUseManager>(module());

    valid_analyses_ = valid_analyses_ | kAnalysisDefUse;

  }

  // Builds the liveness manager from scratch, even if it was already valid.

  void BuildLivenessManager() {

    liveness_mgr_ = MakeUnique<analysis::LivenessManager>(this);

    valid_analyses_ = valid_analyses_ | kAnalysisLiveness;

  }

  // Builds the instruction-block map for the whole module.

  void BuildInstrToBlockMapping() {

    instr_to_block_.clear();

    for (auto& fn : *module_) {

      for (auto& block : fn) {

        block.ForEachInst([this, &block](Instruction* inst) {

          instr_to_block_[inst] = █

        });

      }

    }

    valid_analyses_ = valid_analyses_ | kAnalysisInstrToBlockMapping;

  }

  // Builds the instruction-function map for the whole module.

  void BuildIdToFuncMapping() {

    id_to_func_.clear();

    for (auto& fn : *module_) {

      id_to_func_[fn.result_id()] = &fn;

    }

    valid_analyses_ = valid_analyses_ | kAnalysisIdToFuncMapping;

  }

  void BuildDecorationManager() {

    decoration_mgr_ = MakeUnique<analysis::DecorationManager>(module());

    valid_analyses_ = valid_analyses_ | kAnalysisDecorations;

  }

  void BuildCFG() {

    cfg_ = MakeUnique<CFG>(module());

    valid_analyses_ = valid_analyses_ | kAnalysisCFG;

  }

  void BuildScalarEvolutionAnalysis() {

    scalar_evolution_analysis_ = MakeUnique<ScalarEvolutionAnalysis>(this);

    valid_analyses_ = valid_analyses_ | kAnalysisScalarEvolution;

  }

  // Builds the liveness analysis from scratch, even if it was already valid.

  void BuildRegPressureAnalysis() {

    reg_pressure_ = MakeUnique<LivenessAnalysis>(this);

    valid_analyses_ = valid_analyses_ | kAnalysisRegisterPressure;

  }

  // Builds the value number table analysis from scratch, even if it was already

  // valid.

  void BuildValueNumberTable() {

    vn_table_ = MakeUnique<ValueNumberTable>(this);

    valid_analyses_ = valid_analyses_ | kAnalysisValueNumberTable;

  }

  // Builds the structured CFG analysis from scratch, even if it was already

  // valid.

  void BuildStructuredCFGAnalysis() {

    struct_cfg_analysis_ = MakeUnique<StructuredCFGAnalysis>(this);

    valid_analyses_ = valid_analyses_ | kAnalysisStructuredCFG;

  }

  // Builds the constant manager from scratch, even if it was already

  // valid.

  void BuildConstantManager() {

    constant_mgr_ = MakeUnique<analysis::ConstantManager>(this);

    valid_analyses_ = valid_analyses_ | kAnalysisConstants;

  }

  // Builds the type manager from scratch, even if it was already

  // valid.

  void BuildTypeManager() {

    type_mgr_ = MakeUnique<analysis::TypeManager>(consumer(), this);

    valid_analyses_ = valid_analyses_ | kAnalysisTypes;

  }

  // Builds the debug information manager from scratch, even if it was

  // already valid.

  void BuildDebugInfoManager() {

    debug_info_mgr_ = MakeUnique<analysis::DebugInfoManager>(this);

    valid_analyses_ = valid_analyses_ | kAnalysisDebugInfo;

  }

  // Removes all computed dominator and post-dominator trees. This will force

  // the context to rebuild the trees on demand.

  void ResetDominatorAnalysis() {

    // Clear the cache.

    dominator_trees_.clear();

    post_dominator_trees_.clear();

    valid_analyses_ = valid_analyses_ | kAnalysisDominatorAnalysis;

  }

  // Removes all computed loop descriptors.

  void ResetLoopAnalysis() {

    // Clear the cache.

    loop_descriptors_.clear();

    valid_analyses_ = valid_analyses_ | kAnalysisLoopAnalysis;

  }

  // Removes all computed loop descriptors.

  void ResetBuiltinAnalysis() {

    // Clear the cache.

    builtin_var_id_map_.clear();

    valid_analyses_ = valid_analyses_ | kAnalysisBuiltinVarId;

  }

  // Analyzes the features in the owned module. Builds the manager if required.

  void AnalyzeFeatures() {

    feature_mgr_ =

        std::unique_ptr<FeatureManager>(new FeatureManager(grammar_));

    feature_mgr_->Analyze(module());

  }

  // Scans a module looking for it capabilities, and initializes combinator_ops_

  // accordingly.

  void InitializeCombinators();

  // Add the combinator opcode for the given capability to combinator_ops_.

  void AddCombinatorsForCapability(uint32_t capability);

  // Add the combinator opcode for the given extension to combinator_ops_.

  void AddCombinatorsForExtension(Instruction* extension);

  // Remove |inst| from |id_to_name_| if it is in map.

  void RemoveFromIdToName(const Instruction* inst);

  // Returns true if it is suppose to be valid but it is incorrect.  Returns

  // true if the cfg is invalidated.

  bool CheckCFG();

  // Return id of input variable only decorated with |builtin|, if in module.

  // Return 0 otherwise.

  uint32_t FindBuiltinInputVar(uint32_t builtin);

  // Add |var_id| to all entry points in module.

  void AddVarToEntryPoints(uint32_t var_id);

  // The SPIR-V syntax context containing grammar tables for opcodes and

  // operands.

  spv_context syntax_context_;

  // Auxiliary object for querying SPIR-V grammar facts.

  AssemblyGrammar grammar_;

  // An unique identifier for instructions in |module_|. Can be used to order

  // instructions in a container.

  //

  // This member is initialized to 0, but always issues this value plus one.

  // Therefore, 0 is not a valid unique id for an instruction.

  uint32_t unique_id_;

  // The module being processed within this IR context.

  std::unique_ptr<Module> module_;

  // A message consumer for diagnostics.

  MessageConsumer consumer_;

  // The def-use manager for |module_|.

  std::unique_ptr<analysis::DefUseManager> def_use_mgr_;

  // The instruction decoration manager for |module_|.

  std::unique_ptr<analysis::DecorationManager> decoration_mgr_;

  // The feature manager for |module_|.

  std::unique_ptr<FeatureManager> feature_mgr_;

  // A map from instructions to the basic block they belong to. This mapping is

  // built on-demand when get_instr_block() is called.

  //

  // NOTE: Do not traverse this map. Ever. Use the function and basic block

  // iterators to traverse instructions.

  std::unordered_map<Instruction*, BasicBlock*> instr_to_block_;

  // A map from ids to the function they define. This mapping is

  // built on-demand when GetFunction() is called.

  //

  // NOTE: Do not traverse this map. Ever. Use the function and basic block

  // iterators to traverse instructions.

  std::unordered_map<uint32_t, Function*> id_to_func_;

  // A bitset indicating which analyzes are currently valid.

  Analysis valid_analyses_;

  // Opcodes of shader capability core executable instructions

  // without side-effect.

  std::unordered_map<uint32_t, std::unordered_set<uint32_t>> combinator_ops_;

  // Opcodes of shader capability core executable instructions

  // without side-effect.

  std::unordered_map<uint32_t, uint32_t> builtin_var_id_map_;

  // The CFG for all the functions in |module_|.

  std::unique_ptr<CFG> cfg_;

  // Each function in the module will create its own dominator tree. We cache

  // the result so it doesn't need to be rebuilt each time.

  std::map<const Function*, DominatorAnalysis> dominator_trees_;

  std::map<const Function*, PostDominatorAnalysis> post_dominator_trees_;

  // Cache of loop descriptors for each function.

  std::unordered_map<const Function*, LoopDescriptor> loop_descriptors_;

  // Constant manager for |module_|.

  std::unique_ptr<analysis::ConstantManager> constant_mgr_;

  // Type manager for |module_|.

  std::unique_ptr<analysis::TypeManager> type_mgr_;

  // Debug information manager for |module_|.

  std::unique_ptr<analysis::DebugInfoManager> debug_info_mgr_;

  // A map from an id to its corresponding OpName and OpMemberName instructions.

  std::unique_ptr<std::multimap<uint32_t, Instruction*>> id_to_name_;

  // The cache scalar evolution analysis node.

  std::unique_ptr<ScalarEvolutionAnalysis> scalar_evolution_analysis_;

  // The liveness analysis |module_|.

  std::unique_ptr<LivenessAnalysis> reg_pressure_;

  std::unique_ptr<ValueNumberTable> vn_table_;

  std::unique_ptr<InstructionFolder> inst_folder_;

  std::unique_ptr<StructuredCFGAnalysis> struct_cfg_analysis_;

  // The liveness manager for |module_|.

  std::unique_ptr<analysis::LivenessManager> liveness_mgr_;

  // The maximum legal value for the id bound.

  uint32_t max_id_bound_;

  // Whether all bindings within |module_| should be preserved.

  bool preserve_bindings_;

  // Whether all specialization constants within |module_|

  // should be preserved.

  bool preserve_spec_constants_;

};

inline IRContext::Analysis operator|(IRContext::Analysis lhs,

                                     IRContext::Analysis rhs) {

  return static_cast<IRContext::Analysis>(static_cast<int>(lhs) |

                                          static_cast<int>(rhs));

}

inline IRContext::Analysis& operator|=(IRContext::Analysis& lhs,

                                       IRContext::Analysis rhs) {

  lhs = lhs | rhs;

  return lhs;

}

inline IRContext::Analysis operator<<(IRContext::Analysis a, int shift) {

  return static_cast<IRContext::Analysis>(static_cast<int>(a) << shift);

}

inline IRContext::Analysis& operator<<=(IRContext::Analysis& a, int shift) {

  a = static_cast<IRContext::Analysis>(static_cast<int>(a) << shift);

  return a;

}

std::vector<Instruction*> IRContext::GetConstants() {

  return module()->GetConstants();

}

std::vector<const Instruction*> IRContext::GetConstants() const {

  return ((const Module*)module())->GetConstants();

}

Module::inst_iterator IRContext::annotation_begin() {

  return module()->annotation_begin();

}

Module::inst_iterator IRContext::annotation_end() {

  return module()->annotation_end();

}

IteratorRange<Module::inst_iterator> IRContext::annotations() {

  return module_->annotations();

}

IteratorRange<Module::const_inst_iterator> IRContext::annotations() const {

  return ((const Module*)module_.get())->annotations();

}

Module::inst_iterator IRContext::capability_begin() {

  return module()->capability_begin();

}

Module::inst_iterator IRContext::capability_end() {

  return module()->capability_end();

}

IteratorRange<Module::inst_iterator> IRContext::capabilities() {

  return module()->capabilities();

}

IteratorRange<Module::const_inst_iterator> IRContext::capabilities() const {

  return ((const Module*)module())->capabilities();

}

Module::inst_iterator IRContext::extension_begin() {

  return module()->extension_begin();

}

Module::inst_iterator IRContext::extension_end() {

  return module()->extension_end();

}

IteratorRange<Module::inst_iterator> IRContext::extensions() {

  return module()->extensions();

}

IteratorRange<Module::const_inst_iterator> IRContext::extensions() const {

  return ((const Module*)module())->extensions();

}

Module::inst_iterator IRContext::types_values_begin() {

  return module()->types_values_begin();

}

Module::inst_iterator IRContext::types_values_end() {

  return module()->types_values_end();

}

IteratorRange<Module::inst_iterator> IRContext::types_values() {

  return module()->types_values();

}

IteratorRange<Module::const_inst_iterator> IRContext::types_values() const {

  return ((const Module*)module_.get())->types_values();

}

Module::inst_iterator IRContext::ext_inst_import_begin() {

  return module()->ext_inst_import_begin();

}

Module::inst_iterator IRContext::ext_inst_import_end() {

  return module()->ext_inst_import_end();

}

IteratorRange<Module::inst_iterator> IRContext::ext_inst_imports() {

  return module()->ext_inst_imports();

}

IteratorRange<Module::const_inst_iterator> IRContext::ext_inst_imports() const {

  return ((const Module*)module_.get())->ext_inst_imports();

}

Module::inst_iterator IRContext::debug1_begin() {

  return module()->debug1_begin();

}

Module::inst_iterator IRContext::debug1_end() { return module()->debug1_end(); }

IteratorRange<Module::inst_iterator> IRContext::debugs1() {

  return module()->debugs1();

}

IteratorRange<Module::const_inst_iterator> IRContext::debugs1() const {

  return ((const Module*)module_.get())->debugs1();

}

Module::inst_iterator IRContext::debug2_begin() {

  return module()->debug2_begin();

}

Module::inst_iterator IRContext::debug2_end() { return module()->debug2_end(); }

IteratorRange<Module::inst_iterator> IRContext::debugs2() {

  return module()->debugs2();

}

IteratorRange<Module::const_inst_iterator> IRContext::debugs2() const {