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// Copyright 2022 The Tint Authors.
//
// 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 SRC_TINT_IR_BLOCK_H_
#define SRC_TINT_IR_BLOCK_H_
#include <utility>
#include "src/tint/ir/instruction.h"
#include "src/tint/ir/terminator.h"
#include "src/tint/utils/vector.h"
// Forward declarations
namespace tint::ir {
class ControlInstruction;
} // namespace tint::ir
namespace tint::ir {
/// A block of statements. The instructions in the block are a linear list of instructions to
/// execute. The block will terminate with a Terminator instruction at the end.
class Block : public utils::Castable<Block> {
public:
/// Constructor
Block();
~Block() override;
/// @returns true if this is block has a terminator instruction
bool HasTerminator() {
return instructions_.last != nullptr && instructions_.last->Is<ir::Terminator>();
}
/// @return the terminator instruction for this block
ir::Terminator* Terminator() {
if (!HasTerminator()) {
return nullptr;
}
return instructions_.last->As<ir::Terminator>();
}
/// @returns the instructions in the block
Instruction* Instructions() { return instructions_.first; }
/// Iterator for the instructions inside a block
class Iterator {
public:
/// Constructor
/// @param inst the instruction to start iterating from
explicit Iterator(Instruction* inst) : inst_(inst) {}
~Iterator() = default;
/// Dereference operator
/// @returns the instruction for this iterator
Instruction* operator*() const { return inst_; }
/// Comparison operator
/// @param itr to compare against
/// @returns true if this iterator and @p itr point to the same instruction
bool operator==(const Iterator& itr) const { return itr.inst_ == inst_; }
/// Not equal operator
/// @param itr to compare against
/// @returns true if this iterator and @p itr point to different instructions
bool operator!=(const Iterator& itr) const { return !(*this == itr); }
/// Increment operator
/// @returns this iterator advanced to the next element
Iterator& operator++() {
inst_ = inst_->next;
return *this;
}
private:
Instruction* inst_ = nullptr;
};
/// @returns the iterator pointing to the start of the instruction list
Iterator begin() { return Iterator{instructions_.first}; }
/// @returns the ending iterator
Iterator end() { return Iterator{nullptr}; }
/// @returns the first instruction in the instruction list
Instruction* Front() { return instructions_.first; }
/// @returns the last instruction in the instruction list
Instruction* Back() { return instructions_.last; }
/// Adds the instruction to the beginning of the block
/// @param inst the instruction to add
/// @returns the instruction to allow calls to be chained
Instruction* Prepend(Instruction* inst);
/// Adds the instruction to the end of the block
/// @param inst the instruction to add
/// @returns the instruction to allow calls to be chained
Instruction* Append(Instruction* inst);
/// Adds the new instruction before the given instruction
/// @param before the instruction to insert before
/// @param inst the instruction to insert
void InsertBefore(Instruction* before, Instruction* inst);
/// Adds the new instruction after the given instruction
/// @param after the instruction to insert after
/// @param inst the instruction to insert
void InsertAfter(Instruction* after, Instruction* inst);
/// Replaces the target instruction with the new instruction
/// @param target the instruction to replace
/// @param inst the instruction to insert
void Replace(Instruction* target, Instruction* inst);
/// Removes the target instruction
/// @param inst the instruction to remove
void Remove(Instruction* inst);
/// @returns true if the block contains no instructions
bool IsEmpty() { return Length() == 0; }
/// @returns the number of instructions in the block
size_t Length() { return instructions_.count; }
/// @return the parent instruction that owns this block
ControlInstruction* Parent() { return parent_; }
/// @param parent the parent instruction that owns this block
void SetParent(ControlInstruction* parent) { parent_ = parent; }
private:
struct {
Instruction* first = nullptr;
Instruction* last = nullptr;
size_t count = 0;
} instructions_;
ControlInstruction* parent_ = nullptr;
};
} // namespace tint::ir
#endif // SRC_TINT_IR_BLOCK_H_