ladybird/Userland/Libraries/LibJS/Bytecode/Executable.h
Timothy Flynn 9bbd3103a8 LibJS: Include identifier information in nullish property read access
When a GetById / GetByValue bytecode operation results in accessing a
nullish object, we now include the name of the property and the object
being accessed in the exception message (if available). This should make
it easier to debug live websites.

For example, the following errors would all previously produce a generic
error message of "ToObject on null or undefined":

  > foo = null
  > foo.bar
  Uncaught exception:
  [TypeError] Cannot access property "bar" on null object "foo"
      at <unknown>

  > foo = { bar: undefined }
  > foo.bar.baz
  Uncaught exception:
  [TypeError] Cannot access property "baz" on undefined object "foo.bar"
      at <unknown>

Note we certainly don't capture all possible nullish property read
accesses here. This just covers cases I've seen most on live websites;
we can cover more cases as they arise.
2024-03-29 21:57:19 +01:00

90 lines
2.5 KiB
C++

/*
* Copyright (c) 2021-2024, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/DeprecatedFlyString.h>
#include <AK/HashMap.h>
#include <AK/NonnullOwnPtr.h>
#include <AK/OwnPtr.h>
#include <AK/WeakPtr.h>
#include <LibJS/Bytecode/IdentifierTable.h>
#include <LibJS/Bytecode/Label.h>
#include <LibJS/Bytecode/StringTable.h>
#include <LibJS/Forward.h>
#include <LibJS/Heap/Cell.h>
#include <LibJS/Heap/CellAllocator.h>
#include <LibJS/Runtime/EnvironmentCoordinate.h>
namespace JS::Bytecode {
struct PropertyLookupCache {
WeakPtr<Shape> shape;
Optional<u32> property_offset;
};
struct GlobalVariableCache : public PropertyLookupCache {
u64 environment_serial_number { 0 };
};
using EnvironmentVariableCache = Optional<EnvironmentCoordinate>;
struct SourceRecord {
u32 source_start_offset {};
u32 source_end_offset {};
};
class Executable final : public Cell {
JS_CELL(Executable, Cell);
JS_DECLARE_ALLOCATOR(Executable);
public:
Executable(
NonnullOwnPtr<IdentifierTable>,
NonnullOwnPtr<StringTable>,
NonnullOwnPtr<RegexTable>,
Vector<Value> constants,
NonnullRefPtr<SourceCode const>,
size_t number_of_property_lookup_caches,
size_t number_of_global_variable_caches,
size_t number_of_environment_variable_caches,
size_t number_of_registers,
Vector<NonnullOwnPtr<BasicBlock>>,
bool is_strict_mode);
virtual ~Executable() override;
DeprecatedFlyString name;
Vector<PropertyLookupCache> property_lookup_caches;
Vector<GlobalVariableCache> global_variable_caches;
Vector<EnvironmentVariableCache> environment_variable_caches;
Vector<NonnullOwnPtr<BasicBlock>> basic_blocks;
NonnullOwnPtr<StringTable> string_table;
NonnullOwnPtr<IdentifierTable> identifier_table;
NonnullOwnPtr<RegexTable> regex_table;
Vector<Value> constants;
NonnullRefPtr<SourceCode const> source_code;
size_t number_of_registers { 0 };
bool is_strict_mode { false };
ByteString const& get_string(StringTableIndex index) const { return string_table->get(index); }
DeprecatedFlyString const& get_identifier(IdentifierTableIndex index) const { return identifier_table->get(index); }
Optional<DeprecatedFlyString const&> get_identifier(Optional<IdentifierTableIndex> const& index) const
{
if (!index.has_value())
return {};
return get_identifier(*index);
}
void dump() const;
private:
virtual void visit_edges(Visitor&) override;
};
}