1 // Copyright 2014 the V8 project authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
5 #include "src/compiler.h"
6 #include "src/compiler/all-nodes.h"
7 #include "src/compiler/common-operator.h"
8 #include "src/compiler/control-reducer.h"
9 #include "src/compiler/frame.h"
10 #include "src/compiler/graph.h"
11 #include "src/compiler/graph-visualizer.h"
12 #include "src/compiler/js-graph.h"
13 #include "src/compiler/loop-analysis.h"
14 #include "src/compiler/node.h"
15 #include "src/compiler/node-marker.h"
16 #include "src/compiler/osr.h"
17 #include "src/scopes.h"
23 OsrHelper::OsrHelper(CompilationInfo* info)
24 : parameter_count_(info->scope()->num_parameters()),
25 stack_slot_count_(info->scope()->num_stack_slots() +
26 info->osr_expr_stack_height()) {}
30 #define TRACE_COND (FLAG_trace_turbo_graph && FLAG_trace_osr)
32 #define TRACE_COND false
37 if (TRACE_COND) PrintF(__VA_ARGS__); \
41 // Peel outer loops and rewire the graph so that control reduction can
42 // produce a properly formed graph.
43 static void PeelOuterLoopsForOsr(Graph* graph, CommonOperatorBuilder* common,
44 Zone* tmp_zone, Node* dead,
45 LoopTree* loop_tree, LoopTree::Loop* osr_loop,
46 Node* osr_normal_entry, Node* osr_loop_entry) {
47 const int original_count = graph->NodeCount();
48 AllNodes all(tmp_zone, graph);
49 NodeVector tmp_inputs(tmp_zone);
50 Node* sentinel = graph->NewNode(dead->op());
52 // Make a copy of the graph for each outer loop.
53 ZoneVector<NodeVector*> copies(tmp_zone);
54 for (LoopTree::Loop* loop = osr_loop->parent(); loop; loop = loop->parent()) {
55 void* stuff = tmp_zone->New(sizeof(NodeVector));
57 new (stuff) NodeVector(original_count, sentinel, tmp_zone);
58 copies.push_back(mapping);
59 TRACE("OsrDuplication #%zu, depth %zu, header #%d:%s\n", copies.size(),
60 loop->depth(), loop_tree->HeaderNode(loop)->id(),
61 loop_tree->HeaderNode(loop)->op()->mnemonic());
63 // Prepare the mapping for OSR values and the OSR loop entry.
64 mapping->at(osr_normal_entry->id()) = dead;
65 mapping->at(osr_loop_entry->id()) = dead;
67 // The outer loops are dead in this copy.
68 for (LoopTree::Loop* outer = loop->parent(); outer;
69 outer = outer->parent()) {
70 for (Node* node : loop_tree->HeaderNodes(outer)) {
71 mapping->at(node->id()) = dead;
72 TRACE(" ---- #%d:%s -> dead (header)\n", node->id(),
73 node->op()->mnemonic());
78 for (size_t i = 0; i < all.live.size(); i++) {
79 Node* orig = all.live[i];
80 Node* copy = mapping->at(orig->id());
81 if (copy != sentinel) {
82 // Mapping already exists.
85 if (orig->InputCount() == 0 || orig->opcode() == IrOpcode::kParameter ||
86 orig->opcode() == IrOpcode::kOsrValue) {
87 // No need to copy leaf nodes or parameters.
88 mapping->at(orig->id()) = orig;
94 for (Node* input : orig->inputs()) {
95 tmp_inputs.push_back(mapping->at(input->id()));
97 copy = graph->NewNode(orig->op(), orig->InputCount(), &tmp_inputs[0]);
98 if (NodeProperties::IsTyped(orig)) {
99 NodeProperties::SetBounds(copy, NodeProperties::GetBounds(orig));
101 mapping->at(orig->id()) = copy;
102 TRACE(" copy #%d:%s -> #%d\n", orig->id(), orig->op()->mnemonic(),
106 // Fix missing inputs.
107 for (Node* orig : all.live) {
108 Node* copy = mapping->at(orig->id());
109 for (int j = 0; j < copy->InputCount(); j++) {
110 if (copy->InputAt(j) == sentinel) {
111 copy->ReplaceInput(j, mapping->at(orig->InputAt(j)->id()));
116 // Construct the entry into this loop from previous copies.
118 // Gather the live loop header nodes, {loop_header} first.
119 Node* loop_header = loop_tree->HeaderNode(loop);
120 NodeVector header_nodes(tmp_zone);
121 header_nodes.reserve(loop->HeaderSize());
122 header_nodes.push_back(loop_header); // put the loop header first.
123 for (Node* node : loop_tree->HeaderNodes(loop)) {
124 if (node != loop_header && all.IsLive(node)) {
125 header_nodes.push_back(node);
129 // Gather backedges from the previous copies of the inner loops of {loop}.
130 NodeVectorVector backedges(tmp_zone);
131 TRACE("Gathering backedges...\n");
132 for (int i = 1; i < loop_header->InputCount(); i++) {
134 Node* control = loop_header->InputAt(i);
135 size_t incoming_depth = 0;
136 for (int j = 0; j < control->op()->ControlInputCount(); j++) {
137 Node* k = NodeProperties::GetControlInput(control, j);
139 std::max(incoming_depth, loop_tree->ContainingLoop(k)->depth());
142 TRACE(" edge @%d #%d:%s, incoming depth %zu\n", i, control->id(),
143 control->op()->mnemonic(), incoming_depth);
146 for (int pos = static_cast<int>(copies.size()) - 1; pos >= 0; pos--) {
147 backedges.push_back(NodeVector(tmp_zone));
148 backedges.back().reserve(header_nodes.size());
150 NodeVector* previous_map = pos > 0 ? copies[pos - 1] : nullptr;
152 for (Node* node : header_nodes) {
153 Node* input = node->InputAt(i);
154 if (previous_map) input = previous_map->at(input->id());
155 backedges.back().push_back(input);
156 TRACE(" node #%d:%s(@%d) = #%d:%s\n", node->id(),
157 node->op()->mnemonic(), i, input->id(),
158 input->op()->mnemonic());
163 int backedge_count = static_cast<int>(backedges.size());
164 if (backedge_count == 1) {
165 // Simple case of single backedge, therefore a single entry.
167 for (Node* node : header_nodes) {
168 Node* copy = mapping->at(node->id());
169 Node* input = backedges[0][index];
170 copy->ReplaceInput(0, input);
171 TRACE(" header #%d:%s(0) => #%d:%s\n", copy->id(),
172 copy->op()->mnemonic(), input->id(), input->op()->mnemonic());
176 // Complex case of multiple backedges from previous copies requires
177 // merging the backedges to create the entry into the loop header.
178 Node* merge = nullptr;
180 for (Node* node : header_nodes) {
181 // Gather edge inputs into {tmp_inputs}.
183 for (int edge = 0; edge < backedge_count; edge++) {
184 tmp_inputs.push_back(backedges[edge][index]);
186 Node* copy = mapping->at(node->id());
188 if (node == loop_header) {
189 // Create the merge for the entry into the loop header.
190 input = merge = graph->NewNode(common->Merge(backedge_count),
191 backedge_count, &tmp_inputs[0]);
192 copy->ReplaceInput(0, merge);
194 // Create a phi that merges values at entry into the loop header.
195 DCHECK_NOT_NULL(merge);
196 DCHECK(IrOpcode::IsPhiOpcode(node->opcode()));
197 tmp_inputs.push_back(merge);
198 Node* phi = input = graph->NewNode(
199 common->ResizeMergeOrPhi(node->op(), backedge_count),
200 backedge_count + 1, &tmp_inputs[0]);
201 copy->ReplaceInput(0, phi);
206 TRACE(" header #%d:%s(0) => #%d:%s(", copy->id(),
207 copy->op()->mnemonic(), input->id(), input->op()->mnemonic());
208 for (size_t i = 0; i < tmp_inputs.size(); i++) {
209 if (i > 0) TRACE(", ");
210 Node* input = tmp_inputs[i];
211 TRACE("#%d:%s", input->id(), input->op()->mnemonic());
221 // Kill the outer loops in the original graph.
222 TRACE("Killing outer loop headers...\n");
223 for (LoopTree::Loop* outer = osr_loop->parent(); outer;
224 outer = outer->parent()) {
225 Node* loop_header = loop_tree->HeaderNode(outer);
226 loop_header->ReplaceUses(dead);
227 TRACE(" ---- #%d:%s\n", loop_header->id(), loop_header->op()->mnemonic());
230 // Merge the ends of the graph copies.
231 Node* end = graph->end();
233 for (int i = -1; i < static_cast<int>(copies.size()); i++) {
234 Node* input = end->InputAt(0);
235 if (i >= 0) input = copies[i]->at(input->id());
236 if (input->opcode() == IrOpcode::kMerge) {
237 for (Node* node : input->inputs()) tmp_inputs.push_back(node);
239 tmp_inputs.push_back(input);
242 int count = static_cast<int>(tmp_inputs.size());
243 Node* merge = graph->NewNode(common->Merge(count), count, &tmp_inputs[0]);
244 end->ReplaceInput(0, merge);
246 if (FLAG_trace_turbo_graph) { // Simple textual RPO.
248 os << "-- Graph after OSR duplication -- " << std::endl;
254 static void TransferOsrValueTypesFromLoopPhis(Zone* zone, Node* osr_loop_entry,
256 // Find the index of the osr loop entry into the loop.
258 for (index = 0; index < osr_loop->InputCount(); index++) {
259 if (osr_loop->InputAt(index) == osr_loop_entry) break;
261 if (index == osr_loop->InputCount()) return;
263 for (Node* osr_value : osr_loop_entry->uses()) {
264 if (osr_value->opcode() != IrOpcode::kOsrValue) continue;
266 for (Node* phi : osr_value->uses()) {
267 if (phi->opcode() != IrOpcode::kPhi) continue;
268 if (NodeProperties::GetControlInput(phi) != osr_loop) continue;
269 if (phi->InputAt(index) != osr_value) continue;
270 if (NodeProperties::IsTyped(phi)) {
271 // Transfer the type from the phi to the OSR value itself.
272 Bounds phi_bounds = NodeProperties::GetBounds(phi);
274 NodeProperties::SetBounds(osr_value, phi_bounds);
276 Bounds osr_bounds = NodeProperties::GetBounds(osr_value);
277 NodeProperties::SetBounds(osr_value,
278 Bounds::Both(phi_bounds, osr_bounds, zone));
283 if (unknown) NodeProperties::SetBounds(osr_value, Bounds::Unbounded(zone));
288 bool OsrHelper::Deconstruct(JSGraph* jsgraph, CommonOperatorBuilder* common,
290 Graph* graph = jsgraph->graph();
291 Node* osr_normal_entry = nullptr;
292 Node* osr_loop_entry = nullptr;
293 Node* osr_loop = nullptr;
295 for (Node* node : graph->start()->uses()) {
296 if (node->opcode() == IrOpcode::kOsrLoopEntry) {
297 osr_loop_entry = node; // found the OSR loop entry
298 } else if (node->opcode() == IrOpcode::kOsrNormalEntry) {
299 osr_normal_entry = node;
303 if (osr_loop_entry == nullptr) {
304 // No OSR entry found, do nothing.
305 CHECK(osr_normal_entry);
309 for (Node* use : osr_loop_entry->uses()) {
310 if (use->opcode() == IrOpcode::kLoop) {
311 CHECK(!osr_loop); // should be only one OSR loop.
312 osr_loop = use; // found the OSR loop.
316 CHECK(osr_loop); // Should have found the OSR loop.
318 // Transfer the types from loop phis to the OSR values which flow into them.
319 TransferOsrValueTypesFromLoopPhis(graph->zone(), osr_loop_entry, osr_loop);
321 // Analyze the graph to determine how deeply nested the OSR loop is.
322 LoopTree* loop_tree = LoopFinder::BuildLoopTree(graph, tmp_zone);
324 Node* dead = jsgraph->DeadControl();
325 LoopTree::Loop* loop = loop_tree->ContainingLoop(osr_loop);
326 if (loop->depth() > 0) {
327 PeelOuterLoopsForOsr(graph, common, tmp_zone, dead, loop_tree, loop,
328 osr_normal_entry, osr_loop_entry);
331 // Replace the normal entry with {Dead} and the loop entry with {Start}
332 // and run the control reducer to clean up the graph.
333 osr_normal_entry->ReplaceUses(dead);
334 osr_normal_entry->Kill();
335 osr_loop_entry->ReplaceUses(graph->start());
336 osr_loop_entry->Kill();
338 // Normally the control reducer removes loops whose first input is dead,
339 // but we need to avoid that because the osr_loop is reachable through
340 // the second input, so reduce it and its phis manually.
341 osr_loop->ReplaceInput(0, dead);
342 Node* node = ControlReducer::ReduceMerge(jsgraph, common, osr_loop);
343 if (node != osr_loop) osr_loop->ReplaceUses(node);
345 // Run the normal control reduction, which naturally trims away the dead
346 // parts of the graph.
347 ControlReducer::ReduceGraph(tmp_zone, jsgraph, common);
353 void OsrHelper::SetupFrame(Frame* frame) {
354 // The optimized frame will subsume the unoptimized frame. Do so by reserving
355 // the first spill slots.
356 frame->ReserveSpillSlots(UnoptimizedFrameSlots());
357 // The frame needs to be adjusted by the number of unoptimized frame slots.
358 frame->SetOsrStackSlotCount(static_cast<int>(UnoptimizedFrameSlots()));
362 } // namespace compiler
363 } // namespace internal