gem5/src/gpu-compute/kernel_cfg.cc
Tony Gutierrez 7ac38849ab gpu-compute: remove inst enums and use bit flag for attributes
this patch removes the GPUStaticInst enums that were defined in GPU.py.
instead, a simple set of attribute flags that can be set in the base
instruction class are used. this will help unify the attributes of HSAIL
and machine ISA instructions within the model itself.

because the static instrution now carries the attributes, a GPUDynInst
must carry a pointer to a valid GPUStaticInst so a new static kernel launch
instruction is added, which carries the attributes needed to perform a
the kernel launch.
2016-10-26 22:47:11 -04:00

297 lines
8.8 KiB
C++

/*
* Copyright (c) 2012-2015 Advanced Micro Devices, Inc.
* All rights reserved.
*
* For use for simulation and test purposes only
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2. 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.
*
* 3. Neither the name of the copyright holder 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 HOLDER 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.
*
* Author: Steve Reinhardt
*/
#include "gpu-compute/kernel_cfg.hh"
#include <algorithm>
#include <cassert>
#include <cstdio>
#include <cstring>
#include <iostream>
#include <iterator>
#include <map>
#include <string>
#include "gpu-compute/gpu_static_inst.hh"
void
ControlFlowInfo::assignImmediatePostDominators(
const std::vector<GPUStaticInst*>& instructions)
{
ControlFlowInfo cfg(instructions);
cfg.findImmediatePostDominators();
}
ControlFlowInfo::ControlFlowInfo(const std::vector<GPUStaticInst*>& insts) :
instructions(insts)
{
createBasicBlocks();
connectBasicBlocks();
}
BasicBlock*
ControlFlowInfo::basicBlock(int inst_num) const {
for (auto& block: basicBlocks) {
int first_block_id = block->firstInstruction->instNum();
if (inst_num >= first_block_id &&
inst_num < first_block_id + block->size) {
return block.get();
}
}
return nullptr;
}
GPUStaticInst*
ControlFlowInfo::lastInstruction(const BasicBlock* block) const
{
if (block->isExit()) {
return nullptr;
}
return instructions.at(block->firstInstruction->instNum() +
block->size - 1);
}
BasicBlock*
ControlFlowInfo::postDominator(const BasicBlock* block) const
{
if (block->isExit()) {
return nullptr;
}
return basicBlock(lastInstruction(block)->ipdInstNum());
}
void
ControlFlowInfo::createBasicBlocks()
{
assert(!instructions.empty());
std::set<int> leaders;
// first instruction is a leader
leaders.insert(0);
for (int i = 1; i < instructions.size(); i++) {
GPUStaticInst* instruction = instructions[i];
if (instruction->isBranch()) {
const int target_pc = instruction->getTargetPc();
leaders.insert(target_pc);
leaders.insert(i + 1);
}
}
size_t block_size = 0;
for (int i = 0; i < instructions.size(); i++) {
if (leaders.find(i) != leaders.end()) {
uint32_t id = basicBlocks.size();
if (id > 0) {
basicBlocks.back()->size = block_size;
}
block_size = 0;
basicBlocks.emplace_back(new BasicBlock(id, instructions[i]));
}
block_size++;
}
basicBlocks.back()->size = block_size;
// exit basic block
basicBlocks.emplace_back(new BasicBlock(basicBlocks.size(), nullptr));
}
void
ControlFlowInfo::connectBasicBlocks()
{
BasicBlock* exit_bb = basicBlocks.back().get();
for (auto& bb : basicBlocks) {
if (bb->isExit()) {
break;
}
GPUStaticInst* last = lastInstruction(bb.get());
if (last->isReturn()) {
bb->successorIds.insert(exit_bb->id);
continue;
}
if (last->isBranch()) {
const uint32_t target_pc = last->getTargetPc();
BasicBlock* target_bb = basicBlock(target_pc);
bb->successorIds.insert(target_bb->id);
}
// Unconditional jump instructions have a unique successor
if (!last->isUnconditionalJump()) {
BasicBlock* next_bb = basicBlock(last->instNum() + 1);
bb->successorIds.insert(next_bb->id);
}
}
}
// In-place set intersection
static void
intersect(std::set<uint32_t>& a, const std::set<uint32_t>& b)
{
std::set<uint32_t>::iterator it = a.begin();
while (it != a.end()) {
it = b.find(*it) != b.end() ? ++it : a.erase(it);
}
}
void
ControlFlowInfo::findPostDominators()
{
// the only postdominator of the exit block is itself
basicBlocks.back()->postDominatorIds.insert(basicBlocks.back()->id);
//copy all basic blocks to all postdominator lists except for exit block
for (auto& block : basicBlocks) {
if (!block->isExit()) {
for (uint32_t i = 0; i < basicBlocks.size(); i++) {
block->postDominatorIds.insert(i);
}
}
}
bool change = true;
while (change) {
change = false;
for (int h = basicBlocks.size() - 2; h >= 0; --h) {
size_t num_postdominators =
basicBlocks[h]->postDominatorIds.size();
for (int s : basicBlocks[h]->successorIds) {
intersect(basicBlocks[h]->postDominatorIds,
basicBlocks[s]->postDominatorIds);
}
basicBlocks[h]->postDominatorIds.insert(h);
change |= (num_postdominators
!= basicBlocks[h]->postDominatorIds.size());
}
}
}
// In-place set difference
static void
setDifference(std::set<uint32_t>&a,
const std::set<uint32_t>& b, uint32_t exception)
{
for (uint32_t b_elem : b) {
if (b_elem != exception) {
a.erase(b_elem);
}
}
}
void
ControlFlowInfo::findImmediatePostDominators()
{
assert(basicBlocks.size() > 1); // Entry and exit blocks must be present
findPostDominators();
for (auto& basicBlock : basicBlocks) {
if (basicBlock->isExit()) {
continue;
}
std::set<uint32_t> candidates = basicBlock->postDominatorIds;
candidates.erase(basicBlock->id);
for (uint32_t postDominatorId : basicBlock->postDominatorIds) {
if (postDominatorId != basicBlock->id) {
setDifference(candidates,
basicBlocks[postDominatorId]->postDominatorIds,
postDominatorId);
}
}
assert(candidates.size() == 1);
GPUStaticInst* last_instruction = lastInstruction(basicBlock.get());
BasicBlock* ipd_block = basicBlocks[*(candidates.begin())].get();
if (!ipd_block->isExit()) {
GPUStaticInst* ipd_first_inst = ipd_block->firstInstruction;
last_instruction->ipdInstNum(ipd_first_inst->instNum());
} else {
last_instruction->ipdInstNum(last_instruction->instNum() + 1);
}
}
}
void
ControlFlowInfo::printPostDominators() const
{
for (auto& block : basicBlocks) {
std::cout << "PD(" << block->id << ") = {";
std::copy(block->postDominatorIds.begin(),
block->postDominatorIds.end(),
std::ostream_iterator<uint32_t>(std::cout, ", "));
std::cout << "}" << std::endl;
}
}
void
ControlFlowInfo::printImmediatePostDominators() const
{
for (const auto& block : basicBlocks) {
if (block->isExit()) {
continue;
}
std::cout << "IPD(" << block->id << ") = ";
std::cout << postDominator(block.get())->id << ", ";
}
std::cout << std::endl;
}
void
ControlFlowInfo::printBasicBlocks() const
{
for (GPUStaticInst* inst : instructions) {
int inst_num = inst->instNum();
std::cout << inst_num << " [" << basicBlock(inst_num)->id
<< "]: " << inst->disassemble();
if (inst->isBranch()) {
std::cout << ", PC = " << inst->getTargetPc();
}
std::cout << std::endl;
}
}
void
ControlFlowInfo::printBasicBlockDot() const
{
printf("digraph {\n");
for (const auto& basic_block : basicBlocks) {
printf("\t");
for (uint32_t successorId : basic_block->successorIds) {
printf("%d -> %d; ", basic_block->id, successorId);
}
printf("\n");
}
printf("}\n");
}