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-rw-r--r--src/gpu-compute/kernel_cfg.cc296
1 files changed, 296 insertions, 0 deletions
diff --git a/src/gpu-compute/kernel_cfg.cc b/src/gpu-compute/kernel_cfg.cc
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+/*
+ * 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->o_type == Enums::OT_BRANCH) {
+ 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->o_type == Enums::OT_RET) {
+ bb->successorIds.insert(exit_bb->id);
+ break;
+ }
+ if (last->o_type == Enums::OT_BRANCH) {
+ 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->unconditionalJumpInstruction()) {
+ 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->o_type == Enums::OT_BRANCH) {
+ 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");
+}
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