spvIR.h

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//
// Copyright (C) 2014 LunarG, Inc.
//
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
//
// Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//
// Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
//
// Neither the name of 3Dlabs Inc. Ltd. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
// FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
// COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
// BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
// LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
// ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.

// SPIRV-IR
//
// Simple in-memory representation (IR) of SPIRV. Just for holding
// Each function's CFG of blocks. Has this hierarchy:
// - Module, which is a list of
// - Function, which is a list of
// - Block, which is a list of
// - Instruction
//

#pragma once
#ifndef spvIR_H
#define spvIR_H

#include "spirv.hpp"

#include <algorithm>
#include <cassert>
#include <functional>
#include <iostream>
#include <memory>
#include <vector>

namespace spv {

class Block;
class Function;
class Module;

const Id NoResult = 0;
const Id NoType = 0;

const Decoration NoPrecision = DecorationMax;

#ifdef __GNUC__
# define POTENTIALLY_UNUSED __attribute__((unused))
#else
# define POTENTIALLY_UNUSED
#endif

POTENTIALLY_UNUSED
const MemorySemanticsMask MemorySemanticsAllMemory =
 (MemorySemanticsMask)(MemorySemanticsUniformMemoryMask |
 MemorySemanticsWorkgroupMemoryMask |
 MemorySemanticsAtomicCounterMemoryMask |
 MemorySemanticsImageMemoryMask);

//
// SPIR-V IR instruction.
//

class Instruction {
public:
 Instruction(Id resultId, Id typeId, Op opCode) : resultId(resultId), typeId(typeId), opCode(opCode), block(nullptr) { }
 explicit Instruction(Op opCode) : resultId(NoResult), typeId(NoType), opCode(opCode), block(nullptr) { }
 virtual ~Instruction() {}
 void addIdOperand(Id id) { operands.push_back(id); }
 void addImmediateOperand(unsigned int immediate) { operands.push_back(immediate); }
 void addStringOperand(const char* str)
 {
 unsigned int word;
 char* wordString = (char*)&word;
 char* wordPtr = wordString;
 int charCount = 0;
 char c;
 do {
 c = *(str++);
 *(wordPtr++) = c;
 ++charCount;
 if (charCount == 4) {
 addImmediateOperand(word);
 wordPtr = wordString;
 charCount = 0;
 }
 } while (c != 0);

 // deal with partial last word
 if (charCount > 0) {
 // pad with 0s
 for (; charCount < 4; ++charCount)
 *(wordPtr++) = 0;
 addImmediateOperand(word);
 }
 }
 void setBlock(Block* b) { block = b; }
 Block* getBlock() const { return block; }
 Op getOpCode() const { return opCode; }
 int getNumOperands() const { return (int)operands.size(); }
 Id getResultId() const { return resultId; }
 Id getTypeId() const { return typeId; }
 Id getIdOperand(int op) const { return operands[op]; }
 unsigned int getImmediateOperand(int op) const { return operands[op]; }

 // Write out the binary form.
 void dump(std::vector<unsigned int>& out) const
 {
 // Compute the wordCount
 unsigned int wordCount = 1;
 if (typeId)
 ++wordCount;
 if (resultId)
 ++wordCount;
 wordCount += (unsigned int)operands.size();

 // Write out the beginning of the instruction
 out.push_back(((wordCount) << WordCountShift) | opCode);
 if (typeId)
 out.push_back(typeId);
 if (resultId)
 out.push_back(resultId);

 // Write out the operands
 for (int op = 0; op < (int)operands.size(); ++op)
 out.push_back(operands[op]);
 }

protected:
 Instruction(const Instruction&);
 Id resultId;
 Id typeId;
 Op opCode;
 std::vector<Id> operands;
 Block* block;
};

//
// SPIR-V IR block.
//

class Block {
public:
 Block(Id id, Function& parent);
 virtual ~Block()
 {
 }

 Id getId() { return instructions.front()->getResultId(); }

 Function& getParent() const { return parent; }
 void addInstruction(std::unique_ptr<Instruction> inst);
 void addPredecessor(Block* pred) { predecessors.push_back(pred); pred->successors.push_back(this);}
 void addLocalVariable(std::unique_ptr<Instruction> inst) { localVariables.push_back(std::move(inst)); }
 const std::vector<Block*>& getPredecessors() const { return predecessors; }
 const std::vector<Block*>& getSuccessors() const { return successors; }
 const std::vector<std::unique_ptr<Instruction> >& getInstructions() const {
 return instructions;
 }
 void setUnreachable() { unreachable = true; }
 bool isUnreachable() const { return unreachable; }
 // Returns the block's merge instruction, if one exists (otherwise null).
 const Instruction* getMergeInstruction() const {
 if (instructions.size() < 2) return nullptr;
 const Instruction* nextToLast = (instructions.cend() - 2)->get();
 switch (nextToLast->getOpCode()) {
 case OpSelectionMerge:
 case OpLoopMerge:
 return nextToLast;
 default:
 return nullptr;
 }
 return nullptr;
 }

 bool isTerminated() const
 {
 switch (instructions.back()->getOpCode()) {
 case OpBranch:
 case OpBranchConditional:
 case OpSwitch:
 case OpKill:
 case OpReturn:
 case OpReturnValue:
 return true;
 default:
 return false;
 }
 }

 void dump(std::vector<unsigned int>& out) const
 {
 instructions[0]->dump(out);
 for (int i = 0; i < (int)localVariables.size(); ++i)
 localVariables[i]->dump(out);
 for (int i = 1; i < (int)instructions.size(); ++i)
 instructions[i]->dump(out);
 }

protected:
 Block(const Block&);
 Block& operator=(Block&);

 // To enforce keeping parent and ownership in sync:
 friend Function;

 std::vector<std::unique_ptr<Instruction> > instructions;
 std::vector<Block*> predecessors, successors;
 std::vector<std::unique_ptr<Instruction> > localVariables;
 Function& parent;

 // track whether this block is known to be uncreachable (not necessarily
 // true for all unreachable blocks, but should be set at least
 // for the extraneous ones introduced by the builder).
 bool unreachable;
};

// Traverses the control-flow graph rooted at root in an order suited for
// readable code generation. Invokes callback at every node in the traversal
// order.
void inReadableOrder(Block* root, std::function<void(Block*)> callback);

//
// SPIR-V IR Function.
//

class Function {
public:
 Function(Id id, Id resultType, Id functionType, Id firstParam, Module& parent);
 virtual ~Function()
 {
 for (int i = 0; i < (int)parameterInstructions.size(); ++i)
 delete parameterInstructions[i];

 for (int i = 0; i < (int)blocks.size(); ++i)
 delete blocks[i];
 }
 Id getId() const { return functionInstruction.getResultId(); }
 Id getParamId(int p) const { return parameterInstructions[p]->getResultId(); }
 Id getParamType(int p) const { return parameterInstructions[p]->getTypeId(); }

 void addBlock(Block* block) { blocks.push_back(block); }
 void removeBlock(Block* block)
 {
 auto found = find(blocks.begin(), blocks.end(), block);
 assert(found != blocks.end());
 blocks.erase(found);
 delete block;
 }

 Module& getParent() const { return parent; }
 Block* getEntryBlock() const { return blocks.front(); }
 Block* getLastBlock() const { return blocks.back(); }
 const std::vector<Block*>& getBlocks() const { return blocks; }
 void addLocalVariable(std::unique_ptr<Instruction> inst);
 Id getReturnType() const { return functionInstruction.getTypeId(); }

 void setImplicitThis() { implicitThis = true; }
 bool hasImplicitThis() const { return implicitThis; }

 void dump(std::vector<unsigned int>& out) const
 {
 // OpFunction
 functionInstruction.dump(out);

 // OpFunctionParameter
 for (int p = 0; p < (int)parameterInstructions.size(); ++p)
 parameterInstructions[p]->dump(out);

 // Blocks
 inReadableOrder(blocks[0], [&out](const Block* b) { b->dump(out); });
 Instruction end(0, 0, OpFunctionEnd);
 end.dump(out);
 }

protected:
 Function(const Function&);
 Function& operator=(Function&);

 Module& parent;
 Instruction functionInstruction;
 std::vector<Instruction*> parameterInstructions;
 std::vector<Block*> blocks;
 bool implicitThis; // true if this is a member function expecting to be passed a 'this' as the first argument
};

//
// SPIR-V IR Module.
//

class Module {
public:
 Module() {}
 virtual ~Module()
 {
 // TODO delete things
 }

 void addFunction(Function *fun) { functions.push_back(fun); }

 void mapInstruction(Instruction *instruction)
 {
 spv::Id resultId = instruction->getResultId();
 // map the instruction's result id
 if (resultId >= idToInstruction.size())
 idToInstruction.resize(resultId + 16);
 idToInstruction[resultId] = instruction;
 }

 Instruction* getInstruction(Id id) const { return idToInstruction[id]; }
 const std::vector<Function*>& getFunctions() const { return functions; }
 spv::Id getTypeId(Id resultId) const { return idToInstruction[resultId]->getTypeId(); }
 StorageClass getStorageClass(Id typeId) const
 {
 assert(idToInstruction[typeId]->getOpCode() == spv::OpTypePointer);
 return (StorageClass)idToInstruction[typeId]->getImmediateOperand(0);
 }

 void dump(std::vector<unsigned int>& out) const
 {
 for (int f = 0; f < (int)functions.size(); ++f)
 functions[f]->dump(out);
 }

protected:
 Module(const Module&);
 std::vector<Function*> functions;

 // map from result id to instruction having that result id
 std::vector<Instruction*> idToInstruction;

 // map from a result id to its type id
};

//
// Implementation (it's here due to circular type definitions).
//

// Add both
// - the OpFunction instruction
// - all the OpFunctionParameter instructions
__inline Function::Function(Id id, Id resultType, Id functionType, Id firstParamId, Module& parent)
 : parent(parent), functionInstruction(id, resultType, OpFunction), implicitThis(false)
{
 // OpFunction
 functionInstruction.addImmediateOperand(FunctionControlMaskNone);
 functionInstruction.addIdOperand(functionType);
 parent.mapInstruction(&functionInstruction);
 parent.addFunction(this);

 // OpFunctionParameter
 Instruction* typeInst = parent.getInstruction(functionType);
 int numParams = typeInst->getNumOperands() - 1;
 for (int p = 0; p < numParams; ++p) {
 Instruction* param = new Instruction(firstParamId + p, typeInst->getIdOperand(p + 1), OpFunctionParameter);
 parent.mapInstruction(param);
 parameterInstructions.push_back(param);
 }
}

__inline void Function::addLocalVariable(std::unique_ptr<Instruction> inst)
{
 Instruction* raw_instruction = inst.get();
 blocks[0]->addLocalVariable(std::move(inst));
 parent.mapInstruction(raw_instruction);
}

__inline Block::Block(Id id, Function& parent) : parent(parent), unreachable(false)
{
 instructions.push_back(std::unique_ptr<Instruction>(new Instruction(id, NoType, OpLabel)));
 instructions.back()->setBlock(this);
 parent.getParent().mapInstruction(instructions.back().get());
}

__inline void Block::addInstruction(std::unique_ptr<Instruction> inst)
{
 Instruction* raw_instruction = inst.get();
 instructions.push_back(std::move(inst));
 raw_instruction->setBlock(this);
 if (raw_instruction->getResultId())
 parent.getParent().mapInstruction(raw_instruction);
}

}; // end spv namespace

#endif // spvIR_H