120 lines
4.6 KiB
C++
120 lines
4.6 KiB
C++
// Copyright (c) 2018 Google LLC
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "source/reduce/reduction_util.h"
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#include "source/opt/ir_context.h"
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#include "source/util/make_unique.h"
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namespace spvtools {
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namespace reduce {
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const uint32_t kTrueBranchOperandIndex = 1;
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const uint32_t kFalseBranchOperandIndex = 2;
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uint32_t FindOrCreateGlobalVariable(opt::IRContext* context,
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uint32_t pointer_type_id) {
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for (auto& inst : context->module()->types_values()) {
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if (inst.opcode() != SpvOpVariable) {
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continue;
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}
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if (inst.type_id() == pointer_type_id) {
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return inst.result_id();
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}
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}
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const uint32_t variable_id = context->TakeNextId();
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auto variable_inst = MakeUnique<opt::Instruction>(
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context, SpvOpVariable, pointer_type_id, variable_id,
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opt::Instruction::OperandList(
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{{SPV_OPERAND_TYPE_STORAGE_CLASS,
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{static_cast<uint32_t>(context->get_type_mgr()
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->GetType(pointer_type_id)
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->AsPointer()
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->storage_class())}}}));
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context->module()->AddGlobalValue(std::move(variable_inst));
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return variable_id;
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}
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uint32_t FindOrCreateFunctionVariable(opt::IRContext* context,
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opt::Function* function,
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uint32_t pointer_type_id) {
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// The pointer type of a function variable must have Function storage class.
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assert(context->get_type_mgr()
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->GetType(pointer_type_id)
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->AsPointer()
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->storage_class() == SpvStorageClassFunction);
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// Go through the instructions in the function's first block until we find a
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// suitable variable, or go past all the variables.
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opt::BasicBlock::iterator iter = function->begin()->begin();
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for (;; ++iter) {
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// We will either find a suitable variable, or find a non-variable
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// instruction; we won't exhaust all instructions.
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assert(iter != function->begin()->end());
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if (iter->opcode() != SpvOpVariable) {
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// If we see a non-variable, we have gone through all the variables.
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break;
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}
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if (iter->type_id() == pointer_type_id) {
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return iter->result_id();
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}
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}
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// At this point, iter refers to the first non-function instruction of the
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// function's entry block.
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const uint32_t variable_id = context->TakeNextId();
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auto variable_inst = MakeUnique<opt::Instruction>(
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context, SpvOpVariable, pointer_type_id, variable_id,
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opt::Instruction::OperandList(
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{{SPV_OPERAND_TYPE_STORAGE_CLASS, {SpvStorageClassFunction}}}));
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iter->InsertBefore(std::move(variable_inst));
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return variable_id;
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}
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uint32_t FindOrCreateGlobalUndef(opt::IRContext* context, uint32_t type_id) {
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for (auto& inst : context->module()->types_values()) {
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if (inst.opcode() != SpvOpUndef) {
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continue;
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}
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if (inst.type_id() == type_id) {
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return inst.result_id();
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}
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}
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const uint32_t undef_id = context->TakeNextId();
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auto undef_inst = MakeUnique<opt::Instruction>(
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context, SpvOpUndef, type_id, undef_id, opt::Instruction::OperandList());
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assert(undef_id == undef_inst->result_id());
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context->module()->AddGlobalValue(std::move(undef_inst));
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return undef_id;
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}
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void AdaptPhiInstructionsForRemovedEdge(uint32_t from_id,
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opt::BasicBlock* to_block) {
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to_block->ForEachPhiInst([&from_id](opt::Instruction* phi_inst) {
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opt::Instruction::OperandList new_in_operands;
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// Go through the OpPhi's input operands in (variable, parent) pairs.
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for (uint32_t index = 0; index < phi_inst->NumInOperands(); index += 2) {
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// Keep all pairs where the parent is not the block from which the edge
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// is being removed.
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if (phi_inst->GetInOperand(index + 1).words[0] != from_id) {
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new_in_operands.push_back(phi_inst->GetInOperand(index));
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new_in_operands.push_back(phi_inst->GetInOperand(index + 1));
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}
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}
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phi_inst->SetInOperands(std::move(new_in_operands));
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});
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}
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} // namespace reduce
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} // namespace spvtools
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