mirror of
https://github.com/LadybirdBrowser/ladybird.git
synced 2026-06-23 01:40:26 +00:00
1ce4242b4b
Store compact cache indexes in bytecode instructions instead of raw pointers to the executable cache vectors. This keeps the instruction stream independent from heap addresses and removes pointer fixups when materializing cached bytecode. Resolve the mutable cache pointers at execution time from the current Executable. Bytecode test expectations are updated for the smaller cache operands and resulting instruction offsets.
514 lines
19 KiB
C++
514 lines
19 KiB
C++
/*
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* Copyright (c) 2021-2025, Andreas Kling <andreas@ladybird.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <AK/BinarySearch.h>
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#include <AK/NumericLimits.h>
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#include <AK/QuickSort.h>
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#include <LibGC/Heap.h>
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#include <LibGC/HeapBlock.h>
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#include <LibJS/Bytecode/BasicBlock.h>
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#include <LibJS/Bytecode/Executable.h>
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#include <LibJS/Bytecode/FormatOperand.h>
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#include <LibJS/Bytecode/Instruction.h>
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#include <LibJS/Bytecode/Op.h>
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#include <LibJS/Bytecode/RegexTable.h>
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#include <LibJS/Runtime/Array.h>
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#include <LibJS/Runtime/ExternalMemory.h>
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#include <LibJS/Runtime/SharedFunctionInstanceData.h>
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#include <LibJS/Runtime/Value.h>
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#include <LibJS/SourceCode.h>
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namespace JS::Bytecode {
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GC_DEFINE_ALLOCATOR(Executable);
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GC_DEFINE_ALLOCATOR(ObjectPropertyIteratorCacheData);
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ObjectPropertyIteratorCacheData::ObjectPropertyIteratorCacheData(VM& vm, Vector<PropertyKey> properties, ObjectPropertyIteratorFastPath fast_path, u32 indexed_property_count, bool receiver_has_magical_length_property, GC::Ref<Shape> shape, GC::Ptr<PrototypeChainValidity> prototype_chain_validity)
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: m_properties(move(properties))
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, m_shape(shape)
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, m_prototype_chain_validity(prototype_chain_validity)
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, m_indexed_property_count(indexed_property_count)
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, m_receiver_has_magical_length_property(receiver_has_magical_length_property)
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, m_fast_path(fast_path)
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{
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// The iterator fast path returns JS Values directly, so materialize the
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// cached key list once up front instead of converting PropertyKeys during
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// every ObjectPropertyIteratorNext.
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m_property_values.ensure_capacity(indexed_property_count + m_properties.size());
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for (u32 i = 0; i < indexed_property_count; ++i)
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m_property_values.append(PropertyKey { i }.to_value(vm));
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for (auto const& key : m_properties)
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m_property_values.append(key.to_value(vm));
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if (m_shape->is_dictionary())
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m_shape_dictionary_generation = m_shape->dictionary_generation();
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}
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void ObjectPropertyIteratorCacheData::visit_edges(Visitor& visitor)
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{
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Base::visit_edges(visitor);
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visitor.visit(m_shape);
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visitor.visit(m_prototype_chain_validity);
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visitor.visit(m_property_values.span());
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for (auto& key : m_properties)
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key.visit_edges(visitor);
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}
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size_t ObjectPropertyIteratorCacheData::external_memory_size() const
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{
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auto size = vector_external_memory_size(m_properties);
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size = saturating_add_external_memory_size(size, vector_external_memory_size(m_property_values));
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return size;
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}
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Executable::Executable(
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Vector<u8> bytecode,
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NonnullOwnPtr<IdentifierTable> identifier_table,
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NonnullOwnPtr<PropertyKeyTable> property_key_table,
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NonnullOwnPtr<StringTable> string_table,
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NonnullOwnPtr<RegexTable> regex_table,
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Vector<Value> constants,
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NonnullRefPtr<SourceCode const> source_code,
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size_t number_of_property_lookup_caches,
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size_t number_of_global_variable_caches,
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size_t number_of_template_object_caches,
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size_t number_of_object_shape_caches,
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size_t number_of_object_property_iterator_caches,
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size_t number_of_registers,
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Strict strict)
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: GC::WeakContainer(heap())
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, bytecode(move(bytecode))
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, string_table(move(string_table))
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, identifier_table(move(identifier_table))
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, property_key_table(move(property_key_table))
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, regex_table(move(regex_table))
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, constants(move(constants))
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, source_code(move(source_code))
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, number_of_registers(number_of_registers)
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, is_strict_mode(strict == Strict::Yes)
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{
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property_lookup_caches.resize(number_of_property_lookup_caches);
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global_variable_caches.resize(number_of_global_variable_caches);
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template_object_caches.resize(number_of_template_object_caches);
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object_shape_caches.resize(number_of_object_shape_caches);
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object_property_iterator_caches.resize(number_of_object_property_iterator_caches);
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asm_constants_size = this->constants.size();
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asm_constants_data = this->constants.data();
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}
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Executable::~Executable() = default;
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static SourceMapEntry const* first_real_source_map_entry(Executable const& executable)
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{
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SourceMapEntry const* first_entry = nullptr;
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for (auto const& entry : executable.source_map) {
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if (entry.line == 0 && entry.column == 0)
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continue;
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if (!first_entry || entry.line < first_entry->line || (entry.line == first_entry->line && entry.column < first_entry->column))
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first_entry = &entry;
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}
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return first_entry;
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}
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static void dump_header(StringBuilder& output, Executable const& executable, bool use_color)
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{
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auto const white_bold = use_color ? "\033[37;1m"sv : ""sv;
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auto const reset = use_color ? "\033[0m"sv : ""sv;
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auto const* first_source_map_entry = first_real_source_map_entry(executable);
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u32 hash = 2166136261u; // FNV-1a offset basis
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auto update_hash = [&](u32 value) {
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for (size_t i = 0; i < sizeof(value); ++i) {
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hash ^= (value >> (i * 8)) & 0xFF;
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hash *= 16777619u;
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}
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};
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auto update_hash_with_code_unit = [&](u16 code_unit) {
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hash ^= code_unit & 0xFF;
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hash *= 16777619u;
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hash ^= (code_unit >> 8) & 0xFF;
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hash *= 16777619u;
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};
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auto name_view = executable.name.view();
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for (size_t i = 0; i < name_view.length_in_code_units(); ++i)
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update_hash_with_code_unit(name_view.code_unit_at(i));
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if (first_source_map_entry) {
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update_hash(first_source_map_entry->line);
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update_hash(first_source_map_entry->column);
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}
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update_hash(static_cast<u32>(min(executable.bytecode.size(), static_cast<size_t>(NumericLimits<u32>::max()))));
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if (executable.name.is_empty())
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output.appendff("{}${:08x}{}", white_bold, hash, reset);
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else
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output.appendff("{}{}${:08x}{}", white_bold, executable.name, hash, reset);
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// Show source location if available.
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if (first_source_map_entry) {
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auto filename = executable.source_code->filename();
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if (!filename.is_empty()) {
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// Show just the basename to keep output portable across machines.
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auto last_slash = filename.bytes_as_string_view().find_last('/');
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if (last_slash.has_value())
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filename = MUST(filename.substring_from_byte_offset(last_slash.value() + 1));
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output.appendff(" {}:{}:{}", filename, first_source_map_entry->line, first_source_map_entry->column);
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} else {
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output.appendff(" line {}, column {}", first_source_map_entry->line, first_source_map_entry->column);
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}
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}
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output.append('\n');
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}
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static bool instruction_is_terminator(Instruction const& instruction)
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{
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#define __BYTECODE_OP(op) \
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case Instruction::Type::op: \
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return Op::op::IsTerminator;
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switch (instruction.type()) {
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ENUMERATE_BYTECODE_OPS(__BYTECODE_OP)
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default:
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VERIFY_NOT_REACHED();
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}
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#undef __BYTECODE_OP
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}
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static Vector<u32> collect_basic_block_start_offsets(Executable const& executable)
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{
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Vector<u32> offsets;
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auto append_offset = [&](size_t offset) {
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VERIFY(offset <= NumericLimits<u32>::max());
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auto offset32 = static_cast<u32>(offset);
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if (!offsets.contains_slow(offset32))
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offsets.append(offset32);
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};
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auto append_instruction_offset = [&](size_t offset) {
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if (offset < executable.bytecode.size())
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append_offset(offset);
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};
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append_offset(0);
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for (InstructionStreamIterator it(executable.bytecode, &executable); !it.at_end(); ++it) {
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auto const& instruction = *it;
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auto next_offset = it.offset() + instruction.length();
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const_cast<Instruction&>(instruction).visit_labels([&](Label& label) {
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append_offset(label.address());
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});
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if (instruction_is_terminator(instruction) && next_offset < executable.bytecode.size())
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append_offset(next_offset);
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}
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for (auto const& handler : executable.exception_handlers) {
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append_instruction_offset(handler.start_offset);
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append_instruction_offset(handler.end_offset);
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append_instruction_offset(handler.handler_offset);
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}
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quick_sort(offsets);
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return offsets;
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}
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Optional<size_t> Executable::basic_block_index_for_offset(size_t offset) const
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{
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VERIFY(offset <= NumericLimits<u32>::max());
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auto basic_block_start_offsets = collect_basic_block_start_offsets(*this);
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size_t index = 0;
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if (binary_search(basic_block_start_offsets, static_cast<u32>(offset), &index))
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return index;
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return {};
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}
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static void dump_metadata(StringBuilder& output, Executable const& executable, bool use_color)
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{
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auto const green = use_color ? "\033[32m"sv : ""sv;
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auto const yellow = use_color ? "\033[33m"sv : ""sv;
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auto const blue = use_color ? "\033[34m"sv : ""sv;
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auto const cyan = use_color ? "\033[36m"sv : ""sv;
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auto const reset = use_color ? "\033[0m"sv : ""sv;
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output.appendff(" {}Registers{}: {}\n", green, reset, executable.number_of_registers);
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output.appendff(" {}Blocks{}: {}\n", green, reset, collect_basic_block_start_offsets(executable).size());
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if (!executable.local_variable_names.is_empty()) {
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output.appendff(" {}Locals{}: ", green, reset);
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for (size_t i = 0; i < executable.local_variable_names.size(); ++i) {
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if (i != 0)
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output.append(", "sv);
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output.appendff("{}{}~{}{}", blue, executable.local_variable_names[i].name, i, reset);
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}
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output.append('\n');
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}
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if (!executable.constants.is_empty()) {
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output.appendff(" {}Constants{}:\n", green, reset);
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for (size_t i = 0; i < executable.constants.size(); ++i) {
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auto value = executable.constants[i];
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output.append(" "sv);
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output.appendff("{}[{}]{} = ", yellow, i, reset);
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output.append(cyan);
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if (value.is_special_empty_value())
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output.append("<Empty>"sv);
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else if (value.is_boolean())
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output.appendff("Bool({})", value.as_bool() ? "true"sv : "false"sv);
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else if (value.is_int32())
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output.appendff("Int32({})", value.as_i32());
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else if (value.is_double())
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output.appendff("Double({})", value.as_double());
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else if (value.is_bigint())
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output.appendff("BigInt({})", MUST(value.as_bigint().to_string()));
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else if (value.is_string())
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output.appendff("String(\"{}\")", value.as_string().utf8_string_view());
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else if (value.is_undefined())
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output.append("Undefined"sv);
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else if (value.is_null())
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output.append("Null"sv);
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else
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output.appendff("Value({})", value);
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output.append(reset);
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output.append('\n');
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}
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}
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}
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static void dump_bytecode(StringBuilder& output, Executable const& executable, bool use_color)
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{
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auto const magenta = use_color ? "\033[35;1m"sv : ""sv;
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auto const reset = use_color ? "\033[0m"sv : ""sv;
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InstructionStreamIterator it(executable.bytecode, &executable);
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auto basic_block_start_offsets = collect_basic_block_start_offsets(executable);
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size_t basic_block_offset_index = 0;
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while (!it.at_end()) {
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if (basic_block_offset_index < basic_block_start_offsets.size()
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&& it.offset() == basic_block_start_offsets[basic_block_offset_index]) {
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if (basic_block_offset_index > 0)
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output.append('\n');
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output.appendff("{}block{}{}:\n", magenta, basic_block_offset_index, reset);
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++basic_block_offset_index;
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}
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output.appendff(" [{:4x}] {}\n", it.offset(), (*it).to_byte_string(executable));
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++it;
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}
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}
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void Executable::dump() const
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{
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StringBuilder output;
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dump_header(output, *this, true);
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dump_metadata(output, *this, true);
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output.append('\n');
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dump_bytecode(output, *this, true);
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if (!exception_handlers.is_empty()) {
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output.append("\nException handlers:\n"sv);
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for (auto const& handler : exception_handlers) {
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output.appendff(" [{:4x} .. {:4x}] => handler ", handler.start_offset, handler.end_offset);
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Label handler_label(static_cast<u32>(handler.handler_offset));
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output.appendff("{}\n", format_label(""sv, handler_label, *this));
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}
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}
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output.append('\n');
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warnln("{}", output.string_view());
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}
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String Executable::dump_to_string() const
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{
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StringBuilder output;
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dump_header(output, *this, false);
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dump_metadata(output, *this, false);
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output.append('\n');
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dump_bytecode(output, *this, false);
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if (!exception_handlers.is_empty()) {
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output.append("\nException handlers:\n"sv);
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for (auto const& handler : exception_handlers) {
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output.appendff(" [{:4x} .. {:4x}] => handler ", handler.start_offset, handler.end_offset);
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Label handler_label(static_cast<u32>(handler.handler_offset));
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output.appendff("{}\n", format_label(""sv, handler_label, *this));
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}
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}
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return output.to_string_without_validation();
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}
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void Executable::visit_edges(Visitor& visitor)
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{
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Base::visit_edges(visitor);
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visitor.visit(constants);
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for (auto& cache : template_object_caches)
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visitor.visit(cache.cached_template_object);
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for (auto& cache : object_property_iterator_caches)
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visitor.visit(cache.data);
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for (auto& cache : object_property_iterator_caches)
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visitor.visit(cache.reusable_property_name_iterator);
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for (auto& data : shared_function_data)
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visitor.visit(data);
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for (auto& blueprint : class_blueprints) {
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for (auto& element : blueprint.elements) {
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if (element.literal_value.has_value() && element.literal_value->is_cell())
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visitor.visit(element.literal_value->as_cell());
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}
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}
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property_key_table->visit_edges(visitor);
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}
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size_t Executable::external_memory_size() const
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{
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size_t size = vector_external_memory_size(bytecode);
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size = saturating_add_external_memory_size(size, vector_external_memory_size(property_lookup_caches));
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size = saturating_add_external_memory_size(size, vector_external_memory_size(global_variable_caches));
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size = saturating_add_external_memory_size(size, vector_external_memory_size(template_object_caches));
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size = saturating_add_external_memory_size(size, vector_external_memory_size(object_shape_caches));
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for (auto const& cache : object_shape_caches)
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size = saturating_add_external_memory_size(size, vector_external_memory_size(cache.property_offsets));
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size = saturating_add_external_memory_size(size, vector_external_memory_size(object_property_iterator_caches));
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size = saturating_add_external_memory_size(size, string_table->external_memory_size());
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size = saturating_add_external_memory_size(size, identifier_table->external_memory_size());
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size = saturating_add_external_memory_size(size, property_key_table->external_memory_size());
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size = saturating_add_external_memory_size(size, regex_table->external_memory_size());
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size = saturating_add_external_memory_size(size, vector_external_memory_size(constants));
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size = saturating_add_external_memory_size(size, vector_external_memory_size(shared_function_data));
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size = saturating_add_external_memory_size(size, vector_external_memory_size(class_blueprints));
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for (auto const& blueprint : class_blueprints)
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size = saturating_add_external_memory_size(size, vector_external_memory_size(blueprint.elements));
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size = saturating_add_external_memory_size(size, vector_external_memory_size(exception_handlers));
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size = saturating_add_external_memory_size(size, vector_external_memory_size(source_map));
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size = saturating_add_external_memory_size(size, vector_external_memory_size(local_variable_names));
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size = saturating_add_external_memory_size(size, hash_map_external_memory_size(m_source_range_cache));
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return size;
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}
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static Vector<PropertyLookupCache*>& static_property_lookup_caches()
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{
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static Vector<PropertyLookupCache*> caches;
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return caches;
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}
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StaticPropertyLookupCache::StaticPropertyLookupCache()
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{
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static_property_lookup_caches().append(this);
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}
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static bool cell_is_dead(Cell const* cell)
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{
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auto* block = GC::HeapBlock::from_cell(cell);
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if (!GC::Heap::the().is_live_heap_block(block))
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return true;
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return cell->state() != Cell::State::Live || !cell->is_marked();
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}
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static void clear_cache_entry_if_dead(PropertyLookupCache::Entry& entry)
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{
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if (entry.from_shape && cell_is_dead(entry.from_shape))
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entry.from_shape = nullptr;
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if (entry.shape && cell_is_dead(entry.shape))
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entry.shape = nullptr;
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if (entry.prototype && cell_is_dead(entry.prototype))
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entry.prototype = nullptr;
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if (entry.prototype_chain_validity && cell_is_dead(entry.prototype_chain_validity))
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entry.prototype_chain_validity = nullptr;
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}
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void StaticPropertyLookupCache::sweep_all()
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{
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for (auto* cache : static_property_lookup_caches()) {
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for (auto& entry : cache->entries)
|
|
clear_cache_entry_if_dead(entry);
|
|
}
|
|
}
|
|
|
|
void Executable::remove_dead_cells(Badge<GC::Heap>)
|
|
{
|
|
for (auto& cache : property_lookup_caches) {
|
|
for (auto& entry : cache.entries)
|
|
clear_cache_entry_if_dead(entry);
|
|
}
|
|
for (auto& cache : global_variable_caches) {
|
|
for (auto& entry : cache.entries)
|
|
clear_cache_entry_if_dead(entry);
|
|
}
|
|
for (auto& cache : object_shape_caches) {
|
|
auto* shape = cache.shape.ptr();
|
|
if (shape && cell_is_dead(shape))
|
|
cache.shape = nullptr;
|
|
}
|
|
}
|
|
|
|
Optional<Executable::ExceptionHandlers const&> Executable::exception_handlers_for_offset(size_t offset) const
|
|
{
|
|
// NB: exception_handlers is sorted by start_offset.
|
|
auto* entry = binary_search(exception_handlers, offset, nullptr, [](size_t needle, ExceptionHandlers const& entry) -> int {
|
|
if (needle < entry.start_offset)
|
|
return -1;
|
|
if (needle >= entry.end_offset)
|
|
return 1;
|
|
return 0;
|
|
});
|
|
if (!entry)
|
|
return {};
|
|
return *entry;
|
|
}
|
|
|
|
Optional<SourceRange> Executable::source_range_at(size_t offset) const
|
|
{
|
|
if (offset >= bytecode.size())
|
|
return {};
|
|
if (source_map.is_empty())
|
|
return {};
|
|
size_t low = 0;
|
|
size_t high = source_map.size();
|
|
while (low < high) {
|
|
auto middle = low + (high - low) / 2;
|
|
if (source_map[middle].bytecode_offset <= offset)
|
|
low = middle + 1;
|
|
else
|
|
high = middle;
|
|
}
|
|
if (low == 0)
|
|
return {};
|
|
auto& entry = source_map[low - 1];
|
|
return SourceRange {
|
|
.code = source_code,
|
|
.start = { .line = entry.line, .column = entry.column },
|
|
};
|
|
}
|
|
|
|
SourceRange const& Executable::get_source_range(u32 program_counter)
|
|
{
|
|
return m_source_range_cache.ensure(program_counter, [&] {
|
|
if (auto source_range = source_range_at(program_counter); source_range.has_value())
|
|
return *source_range;
|
|
static SourceRange dummy { SourceCode::create({}, Utf16String {}), {} };
|
|
return dummy;
|
|
});
|
|
}
|
|
|
|
Operand Executable::original_operand_from_raw(u32 raw) const
|
|
{
|
|
// NB: Layout is [registers | locals | constants | arguments]
|
|
if (raw < number_of_registers)
|
|
return Operand { Operand::Type::Register, raw };
|
|
if (raw < registers_and_locals_count)
|
|
return Operand { Operand::Type::Local, raw - local_index_base };
|
|
if (raw < argument_index_base)
|
|
return Operand { Operand::Type::Constant, raw - registers_and_locals_count };
|
|
return Operand { Operand::Type::Argument, raw - argument_index_base };
|
|
}
|
|
|
|
}
|