source/opt/constants.cpp - external/github.com/KhronosGroup/SPIRV-Tools - Git at Google

 // 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.

 #include "source/opt/constants.h"

 #include <unordered_map>
 #include <vector>

 #include "source/opt/ir_context.h"

 namespace spvtools {
 namespace opt {
 namespace analysis {

 float Constant::GetFloat() const {
   assert(type()->AsFloat() != nullptr && type()->AsFloat()->width() == 32);

   if (const FloatConstant* fc = AsFloatConstant()) {
     return fc->GetFloatValue();
   } else {
     assert(AsNullConstant() && "Must be a floating point constant.");
     return 0.0f;
   }
 }

 double Constant::GetDouble() const {
   assert(type()->AsFloat() != nullptr && type()->AsFloat()->width() == 64);

   if (const FloatConstant* fc = AsFloatConstant()) {
     return fc->GetDoubleValue();
   } else {
     assert(AsNullConstant() && "Must be a floating point constant.");
     return 0.0;
   }
 }

 double Constant::GetValueAsDouble() const {
   assert(type()->AsFloat() != nullptr);
   if (type()->AsFloat()->width() == 32) {
     return GetFloat();
   } else {
     assert(type()->AsFloat()->width() == 64);
     return GetDouble();
   }
 }

 uint32_t Constant::GetU32() const {
   assert(type()->AsInteger() != nullptr);
   assert(type()->AsInteger()->width() == 32);

   if (const IntConstant* ic = AsIntConstant()) {
     return ic->GetU32BitValue();
   } else {
     assert(AsNullConstant() && "Must be an integer constant.");
     return 0u;
   }
 }

 uint64_t Constant::GetU64() const {
   assert(type()->AsInteger() != nullptr);
   assert(type()->AsInteger()->width() == 64);

   if (const IntConstant* ic = AsIntConstant()) {
     return ic->GetU64BitValue();
   } else {
     assert(AsNullConstant() && "Must be an integer constant.");
     return 0u;
   }
 }

 int32_t Constant::GetS32() const {
   assert(type()->AsInteger() != nullptr);
   assert(type()->AsInteger()->width() == 32);

   if (const IntConstant* ic = AsIntConstant()) {
     return ic->GetS32BitValue();
   } else {
     assert(AsNullConstant() && "Must be an integer constant.");
     return 0;
   }
 }

 int64_t Constant::GetS64() const {
   assert(type()->AsInteger() != nullptr);
   assert(type()->AsInteger()->width() == 64);

   if (const IntConstant* ic = AsIntConstant()) {
     return ic->GetS64BitValue();
   } else {
     assert(AsNullConstant() && "Must be an integer constant.");
     return 0;
   }
 }

 uint64_t Constant::GetZeroExtendedValue() const {
   const auto* int_type = type()->AsInteger();
   assert(int_type != nullptr);
   const auto width = int_type->width();
   assert(width <= 64);

   uint64_t value = 0;
   if (const IntConstant* ic = AsIntConstant()) {
     if (width <= 32) {
       value = ic->GetU32BitValue();
     } else {
       value = ic->GetU64BitValue();
     }
   } else {
     assert(AsNullConstant() && "Must be an integer constant.");
   }
   return value;
 }

 int64_t Constant::GetSignExtendedValue() const {
   const auto* int_type = type()->AsInteger();
   assert(int_type != nullptr);
   const auto width = int_type->width();
   assert(width <= 64);

   int64_t value = 0;
   if (const IntConstant* ic = AsIntConstant()) {
     if (width <= 32) {
       // Let the C++ compiler do the sign extension.
       value = int64_t(ic->GetS32BitValue());
     } else {
       value = ic->GetS64BitValue();
     }
   } else {
     assert(AsNullConstant() && "Must be an integer constant.");
   }
   return value;
 }

 ConstantManager::ConstantManager(IRContext* ctx) : ctx_(ctx) {
   // Populate the constant table with values from constant declarations in the
   // module.  The values of each OpConstant declaration is the identity
   // assignment (i.e., each constant is its own value).
   for (const auto& inst : ctx_->module()->GetConstants()) {
     MapInst(inst);
   }
 }

 Type* ConstantManager::GetType(const Instruction* inst) const {
   return context()->get_type_mgr()->GetType(inst->type_id());
 }

 std::vector<const Constant*> ConstantManager::GetOperandConstants(
     Instruction* inst) const {
   std::vector<const Constant*> constants;
   for (uint32_t i = 0; i < inst->NumInOperands(); i++) {
     const Operand* operand = &inst->GetInOperand(i);
     if (operand->type != SPV_OPERAND_TYPE_ID) {
       constants.push_back(nullptr);
     } else {
       uint32_t id = operand->words[0];
       const analysis::Constant* constant = FindDeclaredConstant(id);
       constants.push_back(constant);
     }
   }
   return constants;
 }

 uint32_t ConstantManager::FindDeclaredConstant(const Constant* c,
                                                uint32_t type_id) const {
   c = FindConstant(c);
   if (c == nullptr) {
     return 0;
   }

   for (auto range = const_val_to_id_.equal_range(c);
        range.first != range.second; ++range.first) {
     Instruction* const_def =
         context()->get_def_use_mgr()->GetDef(range.first->second);
     if (type_id == 0 || const_def->type_id() == type_id) {
       return range.first->second;
     }
   }
   return 0;
 }

 std::vector<const Constant*> ConstantManager::GetConstantsFromIds(
     const std::vector<uint32_t>& ids) const {
   std::vector<const Constant*> constants;
   for (uint32_t id : ids) {
     if (const Constant* c = FindDeclaredConstant(id)) {
       constants.push_back(c);
     } else {
       return {};
     }
   }
   return constants;
 }

 Instruction* ConstantManager::BuildInstructionAndAddToModule(
     const Constant* new_const, Module::inst_iterator* pos, uint32_t type_id) {
   // TODO(1841): Handle id overflow.
   uint32_t new_id = context()->TakeNextId();
   if (new_id == 0) {
     return nullptr;
   }

   auto new_inst = CreateInstruction(new_id, new_const, type_id);
   if (!new_inst) {
     return nullptr;
   }
   auto* new_inst_ptr = new_inst.get();
   *pos = pos->InsertBefore(std::move(new_inst));
   ++(*pos);
   context()->get_def_use_mgr()->AnalyzeInstDefUse(new_inst_ptr);
   MapConstantToInst(new_const, new_inst_ptr);
   return new_inst_ptr;
 }

 Instruction* ConstantManager::GetDefiningInstruction(
     const Constant* c, uint32_t type_id, Module::inst_iterator* pos) {
   uint32_t decl_id = FindDeclaredConstant(c, type_id);
   if (decl_id == 0) {
     auto iter = context()->types_values_end();
     if (pos == nullptr) pos = &iter;
     return BuildInstructionAndAddToModule(c, pos, type_id);
   } else {
     auto def = context()->get_def_use_mgr()->GetDef(decl_id);
     assert(def != nullptr);
     assert((type_id == 0 || def->type_id() == type_id) &&
            "This constant already has an instruction with a different type.");
     return def;
   }
 }

 std::unique_ptr<Constant> ConstantManager::CreateConstant(
     const Type* type, const std::vector<uint32_t>& literal_words_or_ids) const {
   if (literal_words_or_ids.size() == 0) {
     // Constant declared with OpConstantNull
     return MakeUnique<NullConstant>(type);
   } else if (auto* bt = type->AsBool()) {
     assert(literal_words_or_ids.size() == 1 &&
            "Bool constant should be declared with one operand");
     return MakeUnique<BoolConstant>(bt, literal_words_or_ids.front());
   } else if (auto* it = type->AsInteger()) {
     return MakeUnique<IntConstant>(it, literal_words_or_ids);
   } else if (auto* ft = type->AsFloat()) {
     return MakeUnique<FloatConstant>(ft, literal_words_or_ids);
   } else if (auto* vt = type->AsVector()) {
     auto components = GetConstantsFromIds(literal_words_or_ids);
     if (components.empty()) return nullptr;
     // All components of VectorConstant must be of type Bool, Integer or Float.
     if (!std::all_of(components.begin(), components.end(),
                      [](const Constant* c) {
                        if (c->type()->AsBool() || c->type()->AsInteger() ||
                            c->type()->AsFloat()) {
                          return true;
                        } else {
                          return false;
                        }
                      }))
       return nullptr;
     // All components of VectorConstant must be in the same type.
     const auto* component_type = components.front()->type();
     if (!std::all_of(components.begin(), components.end(),
                      [&component_type](const Constant* c) {
                        if (c->type() == component_type) return true;
                        return false;
                      }))
       return nullptr;
     return MakeUnique<VectorConstant>(vt, components);
   } else if (auto* mt = type->AsMatrix()) {
     auto components = GetConstantsFromIds(literal_words_or_ids);
     if (components.empty()) return nullptr;
     return MakeUnique<MatrixConstant>(mt, components);
   } else if (auto* st = type->AsStruct()) {
     auto components = GetConstantsFromIds(literal_words_or_ids);
     if (components.empty()) return nullptr;
     return MakeUnique<StructConstant>(st, components);
   } else if (auto* at = type->AsArray()) {
     auto components = GetConstantsFromIds(literal_words_or_ids);
     if (components.empty()) return nullptr;
     return MakeUnique<ArrayConstant>(at, components);
   } else {
     return nullptr;
   }
 }

 const Constant* ConstantManager::GetConstantFromInst(const Instruction* inst) {
   std::vector<uint32_t> literal_words_or_ids;

   // Collect the constant defining literals or component ids.
   for (uint32_t i = 0; i < inst->NumInOperands(); i++) {
     literal_words_or_ids.insert(literal_words_or_ids.end(),
                                 inst->GetInOperand(i).words.begin(),
                                 inst->GetInOperand(i).words.end());
   }

   switch (inst->opcode()) {
     // OpConstant{True|False} have the value embedded in the opcode. So they
     // are not handled by the for-loop above. Here we add the value explicitly.
     case SpvOp::SpvOpConstantTrue:
       literal_words_or_ids.push_back(true);
       break;
     case SpvOp::SpvOpConstantFalse:
       literal_words_or_ids.push_back(false);
       break;
     case SpvOp::SpvOpConstantNull:
     case SpvOp::SpvOpConstant:
     case SpvOp::SpvOpConstantComposite:
     case SpvOp::SpvOpSpecConstantComposite:
       break;
     default:
       return nullptr;
   }

   return GetConstant(GetType(inst), literal_words_or_ids);
 }

 std::unique_ptr<Instruction> ConstantManager::CreateInstruction(
     uint32_t id, const Constant* c, uint32_t type_id) const {
   uint32_t type =
       (type_id == 0) ? context()->get_type_mgr()->GetId(c->type()) : type_id;
   if (c->AsNullConstant()) {
     return MakeUnique<Instruction>(context(), SpvOp::SpvOpConstantNull, type,
                                    id, std::initializer_list<Operand>{});
   } else if (const BoolConstant* bc = c->AsBoolConstant()) {
     return MakeUnique<Instruction>(
         context(),
         bc->value() ? SpvOp::SpvOpConstantTrue : SpvOp::SpvOpConstantFalse,
         type, id, std::initializer_list<Operand>{});
   } else if (const IntConstant* ic = c->AsIntConstant()) {
     return MakeUnique<Instruction>(
         context(), SpvOp::SpvOpConstant, type, id,
         std::initializer_list<Operand>{
             Operand(spv_operand_type_t::SPV_OPERAND_TYPE_TYPED_LITERAL_NUMBER,
                     ic->words())});
   } else if (const FloatConstant* fc = c->AsFloatConstant()) {
     return MakeUnique<Instruction>(
         context(), SpvOp::SpvOpConstant, type, id,
         std::initializer_list<Operand>{
             Operand(spv_operand_type_t::SPV_OPERAND_TYPE_TYPED_LITERAL_NUMBER,
                     fc->words())});
   } else if (const CompositeConstant* cc = c->AsCompositeConstant()) {
     return CreateCompositeInstruction(id, cc, type_id);
   } else {
     return nullptr;
   }
 }

 std::unique_ptr<Instruction> ConstantManager::CreateCompositeInstruction(
     uint32_t result_id, const CompositeConstant* cc, uint32_t type_id) const {
   std::vector<Operand> operands;
   Instruction* type_inst = context()->get_def_use_mgr()->GetDef(type_id);
   uint32_t component_index = 0;
   for (const Constant* component_const : cc->GetComponents()) {
     uint32_t component_type_id = 0;
     if (type_inst && type_inst->opcode() == SpvOpTypeStruct) {
       component_type_id = type_inst->GetSingleWordInOperand(component_index);
     } else if (type_inst && type_inst->opcode() == SpvOpTypeArray) {
       component_type_id = type_inst->GetSingleWordInOperand(0);
     }
     uint32_t id = FindDeclaredConstant(component_const, component_type_id);

     if (id == 0) {
       // Cannot get the id of the component constant, while all components
       // should have been added to the module prior to the composite constant.
       // Cannot create OpConstantComposite instruction in this case.
       return nullptr;
     }
     operands.emplace_back(spv_operand_type_t::SPV_OPERAND_TYPE_ID,
                           std::initializer_list<uint32_t>{id});
     component_index++;
   }
   uint32_t type =
       (type_id == 0) ? context()->get_type_mgr()->GetId(cc->type()) : type_id;
   return MakeUnique<Instruction>(context(), SpvOp::SpvOpConstantComposite, type,
                                  result_id, std::move(operands));
 }

 const Constant* ConstantManager::GetConstant(
     const Type* type, const std::vector<uint32_t>& literal_words_or_ids) {
   auto cst = CreateConstant(type, literal_words_or_ids);
   return cst ? RegisterConstant(std::move(cst)) : nullptr;
 }

 std::vector<const analysis::Constant*> Constant::GetVectorComponents(
     analysis::ConstantManager* const_mgr) const {
   std::vector<const analysis::Constant*> components;
   const analysis::VectorConstant* a = this->AsVectorConstant();
   const analysis::Vector* vector_type = this->type()->AsVector();
   assert(vector_type != nullptr);
   if (a != nullptr) {
     for (uint32_t i = 0; i < vector_type->element_count(); ++i) {
       components.push_back(a->GetComponents()[i]);
     }
   } else {
     const analysis::Type* element_type = vector_type->element_type();
     const analysis::Constant* element_null_const =
         const_mgr->GetConstant(element_type, {});
     for (uint32_t i = 0; i < vector_type->element_count(); ++i) {
       components.push_back(element_null_const);
     }
   }
   return components;
 }

 }  // namespace analysis
 }  // namespace opt
 }  // namespace spvtools
	// 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.

	#include "source/opt/constants.h"

	#include <unordered_map>
	#include <vector>

	#include "source/opt/ir_context.h"

	namespace spvtools {
	namespace opt {
	namespace analysis {

	float Constant::GetFloat() const {
	assert(type()->AsFloat() != nullptr && type()->AsFloat()->width() == 32);

	if (const FloatConstant* fc = AsFloatConstant()) {
	return fc->GetFloatValue();
	} else {
	assert(AsNullConstant() && "Must be a floating point constant.");
	return 0.0f;
	}
	}

	double Constant::GetDouble() const {
	assert(type()->AsFloat() != nullptr && type()->AsFloat()->width() == 64);

	if (const FloatConstant* fc = AsFloatConstant()) {
	return fc->GetDoubleValue();
	} else {
	assert(AsNullConstant() && "Must be a floating point constant.");
	return 0.0;
	}
	}

	double Constant::GetValueAsDouble() const {
	assert(type()->AsFloat() != nullptr);
	if (type()->AsFloat()->width() == 32) {
	return GetFloat();
	} else {
	assert(type()->AsFloat()->width() == 64);
	return GetDouble();
	}
	}

	uint32_t Constant::GetU32() const {
	assert(type()->AsInteger() != nullptr);
	assert(type()->AsInteger()->width() == 32);

	if (const IntConstant* ic = AsIntConstant()) {
	return ic->GetU32BitValue();
	} else {
	assert(AsNullConstant() && "Must be an integer constant.");
	return 0u;
	}
	}

	uint64_t Constant::GetU64() const {
	assert(type()->AsInteger() != nullptr);
	assert(type()->AsInteger()->width() == 64);

	if (const IntConstant* ic = AsIntConstant()) {
	return ic->GetU64BitValue();
	} else {
	assert(AsNullConstant() && "Must be an integer constant.");
	return 0u;
	}
	}

	int32_t Constant::GetS32() const {
	assert(type()->AsInteger() != nullptr);
	assert(type()->AsInteger()->width() == 32);

	if (const IntConstant* ic = AsIntConstant()) {
	return ic->GetS32BitValue();
	} else {
	assert(AsNullConstant() && "Must be an integer constant.");
	return 0;
	}
	}

	int64_t Constant::GetS64() const {
	assert(type()->AsInteger() != nullptr);
	assert(type()->AsInteger()->width() == 64);

	if (const IntConstant* ic = AsIntConstant()) {
	return ic->GetS64BitValue();
	} else {
	assert(AsNullConstant() && "Must be an integer constant.");
	return 0;
	}
	}

	uint64_t Constant::GetZeroExtendedValue() const {
	const auto* int_type = type()->AsInteger();
	assert(int_type != nullptr);
	const auto width = int_type->width();
	assert(width <= 64);

	uint64_t value = 0;
	if (const IntConstant* ic = AsIntConstant()) {
	if (width <= 32) {
	value = ic->GetU32BitValue();
	} else {
	value = ic->GetU64BitValue();
	}
	} else {
	assert(AsNullConstant() && "Must be an integer constant.");
	}
	return value;
	}

	int64_t Constant::GetSignExtendedValue() const {
	const auto* int_type = type()->AsInteger();
	assert(int_type != nullptr);
	const auto width = int_type->width();
	assert(width <= 64);

	int64_t value = 0;
	if (const IntConstant* ic = AsIntConstant()) {
	if (width <= 32) {
	// Let the C++ compiler do the sign extension.
	value = int64_t(ic->GetS32BitValue());
	} else {
	value = ic->GetS64BitValue();
	}
	} else {
	assert(AsNullConstant() && "Must be an integer constant.");
	}
	return value;
	}

	ConstantManager::ConstantManager(IRContext* ctx) : ctx_(ctx) {
	// Populate the constant table with values from constant declarations in the
	// module. The values of each OpConstant declaration is the identity
	// assignment (i.e., each constant is its own value).
	for (const auto& inst : ctx_->module()->GetConstants()) {
	MapInst(inst);
	}
	}

	Type* ConstantManager::GetType(const Instruction* inst) const {
	return context()->get_type_mgr()->GetType(inst->type_id());
	}

	std::vector<const Constant*> ConstantManager::GetOperandConstants(
	Instruction* inst) const {
	std::vector<const Constant*> constants;
	for (uint32_t i = 0; i < inst->NumInOperands(); i++) {
	const Operand* operand = &inst->GetInOperand(i);
	if (operand->type != SPV_OPERAND_TYPE_ID) {
	constants.push_back(nullptr);
	} else {
	uint32_t id = operand->words[0];
	const analysis::Constant* constant = FindDeclaredConstant(id);
	constants.push_back(constant);
	}
	}
	return constants;
	}

	uint32_t ConstantManager::FindDeclaredConstant(const Constant* c,
	uint32_t type_id) const {
	c = FindConstant(c);
	if (c == nullptr) {
	return 0;
	}

	for (auto range = const_val_to_id_.equal_range(c);
	range.first != range.second; ++range.first) {
	Instruction* const_def =
	context()->get_def_use_mgr()->GetDef(range.first->second);
	if (type_id == 0 \|\| const_def->type_id() == type_id) {
	return range.first->second;
	}
	}
	return 0;
	}

	std::vector<const Constant*> ConstantManager::GetConstantsFromIds(
	const std::vector<uint32_t>& ids) const {
	std::vector<const Constant*> constants;
	for (uint32_t id : ids) {
	if (const Constant* c = FindDeclaredConstant(id)) {
	constants.push_back(c);
	} else {
	return {};
	}
	}
	return constants;
	}

	Instruction* ConstantManager::BuildInstructionAndAddToModule(
	const Constant* new_const, Module::inst_iterator* pos, uint32_t type_id) {
	// TODO(1841): Handle id overflow.
	uint32_t new_id = context()->TakeNextId();
	if (new_id == 0) {
	return nullptr;
	}

	auto new_inst = CreateInstruction(new_id, new_const, type_id);
	if (!new_inst) {
	return nullptr;
	}
	auto* new_inst_ptr = new_inst.get();
	*pos = pos->InsertBefore(std::move(new_inst));
	++(*pos);
	context()->get_def_use_mgr()->AnalyzeInstDefUse(new_inst_ptr);
	MapConstantToInst(new_const, new_inst_ptr);
	return new_inst_ptr;
	}

	Instruction* ConstantManager::GetDefiningInstruction(
	const Constant* c, uint32_t type_id, Module::inst_iterator* pos) {
	uint32_t decl_id = FindDeclaredConstant(c, type_id);
	if (decl_id == 0) {
	auto iter = context()->types_values_end();
	if (pos == nullptr) pos = &iter;
	return BuildInstructionAndAddToModule(c, pos, type_id);
	} else {
	auto def = context()->get_def_use_mgr()->GetDef(decl_id);
	assert(def != nullptr);
	assert((type_id == 0 \|\| def->type_id() == type_id) &&
	"This constant already has an instruction with a different type.");
	return def;
	}
	}

	std::unique_ptr<Constant> ConstantManager::CreateConstant(
	const Type* type, const std::vector<uint32_t>& literal_words_or_ids) const {
	if (literal_words_or_ids.size() == 0) {
	// Constant declared with OpConstantNull
	return MakeUnique<NullConstant>(type);
	} else if (auto* bt = type->AsBool()) {
	assert(literal_words_or_ids.size() == 1 &&
	"Bool constant should be declared with one operand");
	return MakeUnique<BoolConstant>(bt, literal_words_or_ids.front());
	} else if (auto* it = type->AsInteger()) {
	return MakeUnique<IntConstant>(it, literal_words_or_ids);
	} else if (auto* ft = type->AsFloat()) {
	return MakeUnique<FloatConstant>(ft, literal_words_or_ids);
	} else if (auto* vt = type->AsVector()) {
	auto components = GetConstantsFromIds(literal_words_or_ids);
	if (components.empty()) return nullptr;
	// All components of VectorConstant must be of type Bool, Integer or Float.
	if (!std::all_of(components.begin(), components.end(),
	[](const Constant* c) {
	if (c->type()->AsBool() \|\| c->type()->AsInteger() \|\|
	c->type()->AsFloat()) {
	return true;
	} else {
	return false;
	}
	}))
	return nullptr;
	// All components of VectorConstant must be in the same type.
	const auto* component_type = components.front()->type();
	if (!std::all_of(components.begin(), components.end(),
	[&component_type](const Constant* c) {
	if (c->type() == component_type) return true;
	return false;
	}))
	return nullptr;
	return MakeUnique<VectorConstant>(vt, components);
	} else if (auto* mt = type->AsMatrix()) {
	auto components = GetConstantsFromIds(literal_words_or_ids);
	if (components.empty()) return nullptr;
	return MakeUnique<MatrixConstant>(mt, components);
	} else if (auto* st = type->AsStruct()) {
	auto components = GetConstantsFromIds(literal_words_or_ids);
	if (components.empty()) return nullptr;
	return MakeUnique<StructConstant>(st, components);
	} else if (auto* at = type->AsArray()) {
	auto components = GetConstantsFromIds(literal_words_or_ids);
	if (components.empty()) return nullptr;
	return MakeUnique<ArrayConstant>(at, components);
	} else {
	return nullptr;
	}
	}

	const Constant* ConstantManager::GetConstantFromInst(const Instruction* inst) {
	std::vector<uint32_t> literal_words_or_ids;

	// Collect the constant defining literals or component ids.
	for (uint32_t i = 0; i < inst->NumInOperands(); i++) {
	literal_words_or_ids.insert(literal_words_or_ids.end(),
	inst->GetInOperand(i).words.begin(),
	inst->GetInOperand(i).words.end());
	}

	switch (inst->opcode()) {
	// OpConstant{True\|False} have the value embedded in the opcode. So they
	// are not handled by the for-loop above. Here we add the value explicitly.
	case SpvOp::SpvOpConstantTrue:
	literal_words_or_ids.push_back(true);
	break;
	case SpvOp::SpvOpConstantFalse:
	literal_words_or_ids.push_back(false);
	break;
	case SpvOp::SpvOpConstantNull:
	case SpvOp::SpvOpConstant:
	case SpvOp::SpvOpConstantComposite:
	case SpvOp::SpvOpSpecConstantComposite:
	break;
	default:
	return nullptr;
	}

	return GetConstant(GetType(inst), literal_words_or_ids);
	}

	std::unique_ptr<Instruction> ConstantManager::CreateInstruction(
	uint32_t id, const Constant* c, uint32_t type_id) const {
	uint32_t type =
	(type_id == 0) ? context()->get_type_mgr()->GetId(c->type()) : type_id;
	if (c->AsNullConstant()) {
	return MakeUnique<Instruction>(context(), SpvOp::SpvOpConstantNull, type,
	id, std::initializer_list<Operand>{});
	} else if (const BoolConstant* bc = c->AsBoolConstant()) {
	return MakeUnique<Instruction>(
	context(),
	bc->value() ? SpvOp::SpvOpConstantTrue : SpvOp::SpvOpConstantFalse,
	type, id, std::initializer_list<Operand>{});
	} else if (const IntConstant* ic = c->AsIntConstant()) {
	return MakeUnique<Instruction>(
	context(), SpvOp::SpvOpConstant, type, id,
	std::initializer_list<Operand>{
	Operand(spv_operand_type_t::SPV_OPERAND_TYPE_TYPED_LITERAL_NUMBER,
	ic->words())});
	} else if (const FloatConstant* fc = c->AsFloatConstant()) {
	return MakeUnique<Instruction>(
	context(), SpvOp::SpvOpConstant, type, id,
	std::initializer_list<Operand>{
	Operand(spv_operand_type_t::SPV_OPERAND_TYPE_TYPED_LITERAL_NUMBER,
	fc->words())});
	} else if (const CompositeConstant* cc = c->AsCompositeConstant()) {
	return CreateCompositeInstruction(id, cc, type_id);
	} else {
	return nullptr;
	}
	}

	std::unique_ptr<Instruction> ConstantManager::CreateCompositeInstruction(
	uint32_t result_id, const CompositeConstant* cc, uint32_t type_id) const {
	std::vector<Operand> operands;
	Instruction* type_inst = context()->get_def_use_mgr()->GetDef(type_id);
	uint32_t component_index = 0;
	for (const Constant* component_const : cc->GetComponents()) {
	uint32_t component_type_id = 0;
	if (type_inst && type_inst->opcode() == SpvOpTypeStruct) {
	component_type_id = type_inst->GetSingleWordInOperand(component_index);
	} else if (type_inst && type_inst->opcode() == SpvOpTypeArray) {
	component_type_id = type_inst->GetSingleWordInOperand(0);
	}
	uint32_t id = FindDeclaredConstant(component_const, component_type_id);

	if (id == 0) {
	// Cannot get the id of the component constant, while all components
	// should have been added to the module prior to the composite constant.
	// Cannot create OpConstantComposite instruction in this case.
	return nullptr;
	}
	operands.emplace_back(spv_operand_type_t::SPV_OPERAND_TYPE_ID,
	std::initializer_list<uint32_t>{id});
	component_index++;
	}
	uint32_t type =
	(type_id == 0) ? context()->get_type_mgr()->GetId(cc->type()) : type_id;
	return MakeUnique<Instruction>(context(), SpvOp::SpvOpConstantComposite, type,
	result_id, std::move(operands));
	}

	const Constant* ConstantManager::GetConstant(
	const Type* type, const std::vector<uint32_t>& literal_words_or_ids) {
	auto cst = CreateConstant(type, literal_words_or_ids);
	return cst ? RegisterConstant(std::move(cst)) : nullptr;
	}

	std::vector<const analysis::Constant*> Constant::GetVectorComponents(
	analysis::ConstantManager* const_mgr) const {
	std::vector<const analysis::Constant*> components;
	const analysis::VectorConstant* a = this->AsVectorConstant();
	const analysis::Vector* vector_type = this->type()->AsVector();
	assert(vector_type != nullptr);
	if (a != nullptr) {
	for (uint32_t i = 0; i < vector_type->element_count(); ++i) {
	components.push_back(a->GetComponents()[i]);
	}
	} else {
	const analysis::Type* element_type = vector_type->element_type();
	const analysis::Constant* element_null_const =
	const_mgr->GetConstant(element_type, {});
	for (uint32_t i = 0; i < vector_type->element_count(); ++i) {
	components.push_back(element_null_const);
	}
	}
	return components;
	}

	} // namespace analysis
	} // namespace opt
	} // namespace spvtools