| /* |
| * Copyright (C) 2014-2020 Apple 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: |
| * 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. |
| * |
| * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``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 APPLE INC. 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. |
| */ |
| |
| #include "config.h" |
| #include "DFGIntegerCheckCombiningPhase.h" |
| |
| #if ENABLE(DFG_JIT) |
| |
| #include "DFGGraph.h" |
| #include "DFGInsertionSet.h" |
| #include "DFGPhase.h" |
| #include "JSCJSValueInlines.h" |
| |
| namespace JSC { namespace DFG { |
| |
| namespace DFGIntegerCheckCombiningPhaseInternal { |
| static constexpr bool verbose = false; |
| } |
| |
| class IntegerCheckCombiningPhase : public Phase { |
| public: |
| enum RangeKind { |
| InvalidRangeKind, |
| |
| // This means we did ArithAdd with CheckOverflow. |
| Addition, |
| |
| // This means we did CheckInBounds on some length. |
| ArrayBounds |
| }; |
| |
| struct RangeKey { |
| struct Hash { |
| static unsigned hash(const RangeKey& key) { return key.hash(); } |
| static bool equal(const RangeKey& a, const RangeKey& b) { return a == b; } |
| static constexpr bool safeToCompareToEmptyOrDeleted = false; |
| }; |
| |
| static RangeKey addition(Edge edge) |
| { |
| RangeKey result; |
| result.m_kind = Addition; |
| result.m_source = edge.sanitized(); |
| result.m_key = nullptr; |
| return result; |
| } |
| |
| static RangeKey arrayBounds(Edge edge, Node* key) |
| { |
| RangeKey result; |
| result.m_kind = ArrayBounds; |
| result.m_source = edge.sanitized(); |
| result.m_key = key; |
| return result; |
| } |
| |
| bool operator!() const { return m_kind == InvalidRangeKind; } |
| |
| unsigned hash() const |
| { |
| return m_kind + m_source.hash() + PtrHash<Node*>::hash(m_key); |
| } |
| |
| bool operator==(const RangeKey& other) const |
| { |
| return m_kind == other.m_kind |
| && m_source == other.m_source |
| && m_key == other.m_key; |
| } |
| |
| void dump(PrintStream& out) const |
| { |
| switch (m_kind) { |
| case InvalidRangeKind: |
| out.print("InvalidRangeKind("); |
| break; |
| case Addition: |
| out.print("Addition("); |
| break; |
| case ArrayBounds: |
| out.print("ArrayBounds("); |
| break; |
| } |
| if (m_source) |
| out.print(m_source); |
| else |
| out.print("null"); |
| out.print(", "); |
| if (m_key) |
| out.print(m_key); |
| else |
| out.print("null"); |
| out.print(")"); |
| } |
| |
| RangeKind m_kind { InvalidRangeKind }; |
| Edge m_source; |
| Node* m_key { nullptr }; |
| }; |
| |
| struct RangeKeyAndAddend { |
| RangeKeyAndAddend() = default; |
| |
| RangeKeyAndAddend(RangeKey key, int32_t addend) |
| : m_key(key) |
| , m_addend(addend) |
| { |
| } |
| |
| bool operator!() const { return !m_key && !m_addend; } |
| |
| void dump(PrintStream& out) const |
| { |
| out.print(m_key, " + ", m_addend); |
| } |
| |
| RangeKey m_key; |
| int32_t m_addend { 0 }; |
| }; |
| |
| struct Range { |
| void dump(PrintStream& out) const |
| { |
| out.print("(", m_minBound, " @", m_minOrigin, ") .. (", m_maxBound, " @", m_maxOrigin, "), count = ", m_count, ", hoisted = ", m_hoisted); |
| } |
| |
| int32_t m_minBound { 0 }; |
| int32_t m_maxBound { 0 }; |
| CodeOrigin m_minOrigin; |
| CodeOrigin m_maxOrigin; |
| unsigned m_count { 0 }; // If this is zero then the bounds won't necessarily make sense. |
| bool m_hoisted { false }; |
| Node* m_dependency { nullptr }; |
| }; |
| |
| IntegerCheckCombiningPhase(Graph& graph) |
| : Phase(graph, "integer check combining") |
| , m_insertionSet(graph) |
| { |
| } |
| |
| bool run() |
| { |
| ASSERT(m_graph.m_form == SSA); |
| |
| m_changed = false; |
| |
| for (BlockIndex blockIndex = m_graph.numBlocks(); blockIndex--;) |
| handleBlock(blockIndex); |
| |
| return m_changed; |
| } |
| |
| private: |
| void handleBlock(BlockIndex blockIndex) |
| { |
| BasicBlock* block = m_graph.block(blockIndex); |
| if (!block) |
| return; |
| |
| m_map.clear(); |
| |
| // First we collect Ranges. If operations within the range have enough redundancy, |
| // we hoist. And then we remove additions and checks that fall within the max range. |
| |
| for (auto* node : *block) { |
| RangeKeyAndAddend data = rangeKeyAndAddend(node); |
| if (DFGIntegerCheckCombiningPhaseInternal::verbose) |
| dataLog("For ", node, ": ", data, "\n"); |
| if (!data) |
| continue; |
| |
| Range& range = m_map.add(data.m_key, Range { }).iterator->value; |
| if (DFGIntegerCheckCombiningPhaseInternal::verbose) |
| dataLog(" Range: ", range, "\n"); |
| if (range.m_count) { |
| if (data.m_addend > range.m_maxBound) { |
| range.m_maxBound = data.m_addend; |
| range.m_maxOrigin = node->origin.semantic; |
| } else if (data.m_addend < range.m_minBound) { |
| range.m_minBound = data.m_addend; |
| range.m_minOrigin = node->origin.semantic; |
| } |
| } else { |
| range.m_maxBound = data.m_addend; |
| range.m_minBound = data.m_addend; |
| range.m_minOrigin = node->origin.semantic; |
| range.m_maxOrigin = node->origin.semantic; |
| } |
| range.m_count++; |
| if (DFGIntegerCheckCombiningPhaseInternal::verbose) |
| dataLog(" New range: ", range, "\n"); |
| } |
| |
| for (unsigned nodeIndex = 0; nodeIndex < block->size(); ++nodeIndex) { |
| Node* node = block->at(nodeIndex); |
| RangeKeyAndAddend data = rangeKeyAndAddend(node); |
| if (!data) |
| continue; |
| Range range = m_map.get(data.m_key); |
| if (!isValid(data.m_key, range)) |
| continue; |
| |
| // Do the hoisting. |
| if (!range.m_hoisted) { |
| NodeOrigin minOrigin = node->origin.withSemantic(range.m_minOrigin); |
| NodeOrigin maxOrigin = node->origin.withSemantic(range.m_maxOrigin); |
| |
| switch (data.m_key.m_kind) { |
| case Addition: { |
| if (range.m_minBound < 0) |
| insertAdd(nodeIndex, minOrigin, data.m_key.m_source, range.m_minBound); |
| if (range.m_maxBound > 0) |
| insertAdd(nodeIndex, maxOrigin, data.m_key.m_source, range.m_maxBound); |
| break; |
| } |
| |
| case ArrayBounds: { |
| Node* minNode; |
| Node* maxNode; |
| |
| if (!data.m_key.m_source) { |
| // data.m_key.m_source being null means that we're comparing against int32 constants (see rangeKeyAndAddend()). |
| // Since CheckInBounds does an unsigned comparison, if the minBound >= 0, it is also covered by the |
| // maxBound comparison. However, if minBound < 0, then CheckInBounds should always fail its speculation check. |
| // We'll force an OSR exit in that case. |
| minNode = nullptr; |
| if (range.m_minBound < 0) |
| m_insertionSet.insertNode(nodeIndex, SpecNone, ForceOSRExit, node->origin); |
| maxNode = m_insertionSet.insertConstant( |
| nodeIndex, maxOrigin, jsNumber(range.m_maxBound)); |
| } else { |
| minNode = insertAdd( |
| nodeIndex, minOrigin, data.m_key.m_source, range.m_minBound, |
| Arith::Unchecked); |
| maxNode = insertAdd( |
| nodeIndex, maxOrigin, data.m_key.m_source, range.m_maxBound, |
| Arith::Unchecked); |
| } |
| |
| Node* minCheck = nullptr; |
| if (minNode) { |
| minCheck = m_insertionSet.insertNode( |
| nodeIndex, SpecNone, CheckInBounds, node->origin, |
| Edge(minNode, Int32Use), Edge(data.m_key.m_key, Int32Use)); |
| } |
| m_map.find(data.m_key)->value.m_dependency = m_insertionSet.insertNode( |
| nodeIndex, SpecNone, CheckInBounds, node->origin, |
| Edge(maxNode, Int32Use), Edge(data.m_key.m_key, Int32Use), Edge(minCheck, UntypedUse)); |
| break; |
| } |
| |
| default: |
| RELEASE_ASSERT_NOT_REACHED(); |
| } |
| |
| m_changed = true; |
| m_map.find(data.m_key)->value.m_hoisted = true; |
| } |
| |
| // Do the elimination. |
| switch (data.m_key.m_kind) { |
| case Addition: |
| node->setArithMode(Arith::Unchecked); |
| m_changed = true; |
| break; |
| |
| case ArrayBounds: |
| ASSERT(node->op() == CheckInBounds); |
| if (UNLIKELY(Options::validateBoundsCheckElimination())) |
| m_insertionSet.insertNode(nodeIndex, SpecNone, AssertInBounds, node->origin, node->child1(), node->child2()); |
| node->convertToIdentityOn(m_map.get(data.m_key).m_dependency); |
| m_changed = true; |
| break; |
| |
| default: |
| RELEASE_ASSERT_NOT_REACHED(); |
| } |
| } |
| |
| m_insertionSet.execute(block); |
| } |
| |
| RangeKeyAndAddend rangeKeyAndAddend(Node* node) |
| { |
| switch (node->op()) { |
| case ArithAdd: { |
| if (node->arithMode() != Arith::CheckOverflow |
| && node->arithMode() != Arith::CheckOverflowAndNegativeZero) |
| break; |
| if (!node->child2()->isInt32Constant()) |
| break; |
| return RangeKeyAndAddend( |
| RangeKey::addition(node->child1()), |
| node->child2()->asInt32()); |
| } |
| |
| case CheckInBounds: { |
| Edge source; |
| int32_t addend; |
| Node* key = node->child2().node(); |
| |
| Edge index = node->child1(); |
| |
| if (index->isInt32Constant()) { |
| source = Edge(); |
| addend = index->asInt32(); |
| } else if ( |
| index->op() == ArithAdd |
| && index->isBinaryUseKind(Int32Use) |
| && index->child2()->isInt32Constant()) { |
| source = index->child1(); |
| addend = index->child2()->asInt32(); |
| } else { |
| source = index; |
| addend = 0; |
| } |
| |
| return RangeKeyAndAddend(RangeKey::arrayBounds(source, key), addend); |
| } |
| |
| default: |
| break; |
| } |
| |
| return RangeKeyAndAddend(); |
| } |
| |
| bool isValid(const RangeKey& key, const Range& range) |
| { |
| if (range.m_count < 2) |
| return false; |
| |
| switch (key.m_kind) { |
| case ArrayBounds: { |
| // Have to do this carefully because C++ compilers are too smart. But all we're really doing is detecting if |
| // the difference between the bounds is 2^31 or more. If it was, then we'd have to worry about wrap-around. |
| // The way we'd like to write this expression is (range.m_maxBound - range.m_minBound) >= 0, but that is a |
| // signed subtraction and compare, which allows the C++ compiler to do anything it wants in case of |
| // wrap-around. |
| uint32_t maxBound = range.m_maxBound; |
| uint32_t minBound = range.m_minBound; |
| uint32_t unsignedDifference = maxBound - minBound; |
| return !(unsignedDifference >> 31); |
| } |
| |
| default: |
| return true; |
| } |
| } |
| |
| Node* insertAdd( |
| unsigned nodeIndex, NodeOrigin origin, Edge source, int32_t addend, |
| Arith::Mode arithMode = Arith::CheckOverflow) |
| { |
| if (!addend) |
| return source.node(); |
| return m_insertionSet.insertNode( |
| nodeIndex, source->prediction(), source->result(), |
| ArithAdd, origin, OpInfo(arithMode), source, |
| m_insertionSet.insertConstantForUse( |
| nodeIndex, origin, jsNumber(addend), source.useKind())); |
| } |
| |
| using RangeMap = HashMap<GenericHashKey<RangeKey, RangeKey::Hash>, Range>; |
| RangeMap m_map; |
| |
| InsertionSet m_insertionSet; |
| bool m_changed; |
| }; |
| |
| bool performIntegerCheckCombining(Graph& graph) |
| { |
| return runPhase<IntegerCheckCombiningPhase>(graph); |
| } |
| |
| } } // namespace JSC::DFG |
| |
| #endif // ENABLE(DFG_JIT) |
| |
