Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 1 | // Copyright 2015 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. |
| 4 | |
| 5 | #include "src/compiler/js-inlining-heuristic.h" |
| 6 | |
| 7 | #include "src/compiler.h" |
| 8 | #include "src/compiler/node-matchers.h" |
| 9 | #include "src/objects-inl.h" |
| 10 | |
| 11 | namespace v8 { |
| 12 | namespace internal { |
| 13 | namespace compiler { |
| 14 | |
| 15 | Reduction JSInliningHeuristic::Reduce(Node* node) { |
| 16 | if (!IrOpcode::IsInlineeOpcode(node->opcode())) return NoChange(); |
| 17 | |
| 18 | // Check if we already saw that {node} before, and if so, just skip it. |
| 19 | if (seen_.find(node->id()) != seen_.end()) return NoChange(); |
| 20 | seen_.insert(node->id()); |
| 21 | |
| 22 | Node* callee = node->InputAt(0); |
| 23 | HeapObjectMatcher match(callee); |
| 24 | if (!match.HasValue() || !match.Value()->IsJSFunction()) return NoChange(); |
| 25 | Handle<JSFunction> function = Handle<JSFunction>::cast(match.Value()); |
| 26 | |
| 27 | // Functions marked with %SetForceInlineFlag are immediately inlined. |
| 28 | if (function->shared()->force_inline()) { |
| 29 | return inliner_.ReduceJSCall(node, function); |
| 30 | } |
| 31 | |
| 32 | // Handling of special inlining modes right away: |
| 33 | // - For restricted inlining: stop all handling at this point. |
| 34 | // - For stressing inlining: immediately handle all functions. |
| 35 | switch (mode_) { |
| 36 | case kRestrictedInlining: |
| 37 | return NoChange(); |
| 38 | case kStressInlining: |
| 39 | return inliner_.ReduceJSCall(node, function); |
| 40 | case kGeneralInlining: |
| 41 | break; |
| 42 | } |
| 43 | |
| 44 | // --------------------------------------------------------------------------- |
| 45 | // Everything below this line is part of the inlining heuristic. |
| 46 | // --------------------------------------------------------------------------- |
| 47 | |
| 48 | // Built-in functions are handled by the JSBuiltinReducer. |
| 49 | if (function->shared()->HasBuiltinFunctionId()) return NoChange(); |
| 50 | |
| 51 | // Don't inline builtins. |
| 52 | if (function->shared()->IsBuiltin()) return NoChange(); |
| 53 | |
| 54 | // Quick check on source code length to avoid parsing large candidate. |
| 55 | if (function->shared()->SourceSize() > FLAG_max_inlined_source_size) { |
| 56 | return NoChange(); |
| 57 | } |
| 58 | |
| 59 | // Quick check on the size of the AST to avoid parsing large candidate. |
| 60 | if (function->shared()->ast_node_count() > FLAG_max_inlined_nodes) { |
| 61 | return NoChange(); |
| 62 | } |
| 63 | |
| 64 | // Avoid inlining within or across the boundary of asm.js code. |
| 65 | if (info_->shared_info()->asm_function()) return NoChange(); |
| 66 | if (function->shared()->asm_function()) return NoChange(); |
| 67 | |
| 68 | // Stop inlinining once the maximum allowed level is reached. |
| 69 | int level = 0; |
| 70 | for (Node* frame_state = NodeProperties::GetFrameStateInput(node, 0); |
| 71 | frame_state->opcode() == IrOpcode::kFrameState; |
| 72 | frame_state = NodeProperties::GetFrameStateInput(frame_state, 0)) { |
| 73 | if (++level > FLAG_max_inlining_levels) return NoChange(); |
| 74 | } |
| 75 | |
| 76 | // Gather feedback on how often this call site has been hit before. |
| 77 | int calls = -1; // Same default as CallICNexus::ExtractCallCount. |
| 78 | // TODO(turbofan): We also want call counts for constructor calls. |
| 79 | if (node->opcode() == IrOpcode::kJSCallFunction) { |
| 80 | CallFunctionParameters p = CallFunctionParametersOf(node->op()); |
| 81 | if (p.feedback().IsValid()) { |
| 82 | CallICNexus nexus(p.feedback().vector(), p.feedback().slot()); |
| 83 | calls = nexus.ExtractCallCount(); |
| 84 | } |
| 85 | } |
| 86 | |
| 87 | // --------------------------------------------------------------------------- |
| 88 | // Everything above this line is part of the inlining heuristic. |
| 89 | // --------------------------------------------------------------------------- |
| 90 | |
| 91 | // In the general case we remember the candidate for later. |
| 92 | candidates_.insert({function, node, calls}); |
| 93 | return NoChange(); |
| 94 | } |
| 95 | |
| 96 | |
| 97 | void JSInliningHeuristic::Finalize() { |
| 98 | if (candidates_.empty()) return; // Nothing to do without candidates. |
| 99 | if (FLAG_trace_turbo_inlining) PrintCandidates(); |
| 100 | |
| 101 | // We inline at most one candidate in every iteration of the fixpoint. |
| 102 | // This is to ensure that we don't consume the full inlining budget |
| 103 | // on things that aren't called very often. |
| 104 | // TODO(bmeurer): Use std::priority_queue instead of std::set here. |
| 105 | while (!candidates_.empty()) { |
| 106 | if (cumulative_count_ > FLAG_max_inlined_nodes_cumulative) return; |
| 107 | auto i = candidates_.begin(); |
| 108 | Candidate candidate = *i; |
| 109 | candidates_.erase(i); |
| 110 | // Make sure we don't try to inline dead candidate nodes. |
| 111 | if (!candidate.node->IsDead()) { |
| 112 | Reduction r = inliner_.ReduceJSCall(candidate.node, candidate.function); |
| 113 | if (r.Changed()) { |
| 114 | cumulative_count_ += candidate.function->shared()->ast_node_count(); |
| 115 | return; |
| 116 | } |
| 117 | } |
| 118 | } |
| 119 | } |
| 120 | |
| 121 | |
| 122 | bool JSInliningHeuristic::CandidateCompare::operator()( |
| 123 | const Candidate& left, const Candidate& right) const { |
| 124 | return left.node != right.node && left.calls >= right.calls; |
| 125 | } |
| 126 | |
| 127 | |
| 128 | void JSInliningHeuristic::PrintCandidates() { |
| 129 | PrintF("Candidates for inlining (size=%zu):\n", candidates_.size()); |
| 130 | for (const Candidate& candidate : candidates_) { |
| 131 | PrintF(" id:%d, calls:%d, size[source]:%d, size[ast]:%d / %s\n", |
| 132 | candidate.node->id(), candidate.calls, |
| 133 | candidate.function->shared()->SourceSize(), |
| 134 | candidate.function->shared()->ast_node_count(), |
| 135 | candidate.function->shared()->DebugName()->ToCString().get()); |
| 136 | } |
| 137 | } |
| 138 | |
| 139 | } // namespace compiler |
| 140 | } // namespace internal |
| 141 | } // namespace v8 |