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LibJS: Make one compact allocation for CallExpression and its Arguments

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Instead of CallExpression storing its arguments in a Vector<Argument>,
we now custom-allocate the memory slot for CallExpression (and its
subclass NewExpression) so that it fits both CallExpression and its list
of Arguments in one allocation.

This reduces memory usage on twitter.com/awesomekling by 8.8 MiB :^)
This commit is contained in:
Andreas Kling 2022-11-26 19:51:50 +01:00 • committed by Linus Groh
parent 8a8d8ecb35
commit b894acd6b2
4 changed files with 56 additions and 32 deletions
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62
Userland/Libraries/LibJS/AST.h
View file

@ -1472,19 +1472,18 @@ public:
virtual Bytecode::CodeGenerationErrorOr<void> generate_bytecode(Bytecode::Generator&) const override;
};
class CallExpression : public Expression {
public:
struct Argument {
NonnullRefPtr<Expression> value;
bool is_spread;
};
struct CallExpressionArgument {
NonnullRefPtr<Expression> value;
bool is_spread;
};
CallExpression(SourceRange source_range, NonnullRefPtr<Expression> callee, Vector<Argument> arguments = {})
: Expression(source_range)
, m_callee(move(callee))
, m_arguments(move(arguments))
{
}
class CallExpression : public ASTNodeWithTailArray<CallExpression, Expression, CallExpressionArgument> {
friend class ASTNodeWithTailArray;
public:
using Argument = CallExpressionArgument;
static NonnullRefPtr<CallExpression> create(SourceRange, NonnullRefPtr<Expression> callee, Span<Argument const> arguments);
virtual Completion execute(Interpreter&) const override;
virtual void dump(int indent) const override;
@ -1492,6 +1491,22 @@ public:
Expression const& callee() const { return m_callee; }
Span<Argument const> arguments() const { return tail_span(); }
protected:
CallExpression(SourceRange source_range, NonnullRefPtr<Expression> callee, Span<Argument const> arguments)
: ASTNodeWithTailArray(move(source_range), arguments)
, m_callee(move(callee))
{
}
private:
struct ThisAndCallee {
Value this_value;
Value callee;
};
ThrowCompletionOr<ThisAndCallee> compute_this_and_callee(Interpreter&, Reference const&) const;
protected:
virtual bool is_call_expression() const override { return true; }
@ -1499,28 +1514,27 @@ protected:
Optional<DeprecatedString> expression_string() const;
NonnullRefPtr<Expression> m_callee;
Vector<Argument> const m_arguments;
private:
struct ThisAndCallee {
Value this_value;
Value callee;
};
ThrowCompletionOr<ThisAndCallee> compute_this_and_callee(Interpreter&, Reference const&) const;
};
class NewExpression final : public CallExpression {
friend class ASTNodeWithTailArray;
public:
NewExpression(SourceRange source_range, NonnullRefPtr<Expression> callee, Vector<Argument> arguments = {})
: CallExpression(source_range, move(callee), move(arguments))
{
}
static NonnullRefPtr<NewExpression> create(SourceRange, NonnullRefPtr<Expression> callee, Span<Argument const> arguments);
virtual Completion execute(Interpreter&) const override;
virtual bool is_new_expression() const override { return true; }
private:
NewExpression(SourceRange source_range, NonnullRefPtr<Expression> callee, Span<Argument const> arguments)
: CallExpression(move(source_range), move(callee), arguments)
{
}
};
static_assert(sizeof(NewExpression) == sizeof(CallExpression), "Adding members to NewExpression will break CallExpression memory layout");
class SuperCall final : public Expression {
public:
// This is here to be able to make a constructor like