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LibJS: More properly implement scoping rules in bytecode codegen

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Now we emit CreateVariable and SetVariable with the appropriate
initialization/environment modes, much closer to the spec.
This makes a whole lot of things like let/const variables, function
and variable hoisting and some other things work :^)
This commit is contained in:
Ali Mohammad Pur 2022-02-12 19:48:45 +03:30 • committed by Linus Groh
parent c7e6b65fd2
commit 1bbfaf8627
12 changed files with 503 additions and 38 deletions
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72
Userland/Libraries/LibJS/Bytecode/Op.h
View file

@ -282,11 +282,34 @@ private:
Register m_lhs;
};
class SetVariable final : public Instruction {
enum class EnvironmentMode {
Lexical,
Var,
};
class CreateEnvironment final : public Instruction {
public:
explicit SetVariable(IdentifierTableIndex identifier)
: Instruction(Type::SetVariable)
explicit CreateEnvironment(EnvironmentMode mode)
: Instruction(Type::CreateEnvironment)
, m_mode(mode)
{
}
ThrowCompletionOr<void> execute_impl(Bytecode::Interpreter&) const;
String to_string_impl(Bytecode::Executable const&) const;
void replace_references_impl(BasicBlock const&, BasicBlock const&) { }
private:
EnvironmentMode m_mode { EnvironmentMode::Lexical };
};
class CreateVariable final : public Instruction {
public:
explicit CreateVariable(IdentifierTableIndex identifier, EnvironmentMode mode, bool is_immutable)
: Instruction(Type::CreateVariable)
, m_identifier(identifier)
, m_mode(mode)
, m_is_immutable(is_immutable)
{
}
@ -296,6 +319,33 @@ public:
private:
IdentifierTableIndex m_identifier;
EnvironmentMode m_mode;
bool m_is_immutable { false };
};
class SetVariable final : public Instruction {
public:
enum class InitializationMode {
Initialize,
Set,
InitializeOrSet,
};
explicit SetVariable(IdentifierTableIndex identifier, InitializationMode initialization_mode = InitializationMode::Set, EnvironmentMode mode = EnvironmentMode::Lexical)
: Instruction(Type::SetVariable)
, m_identifier(identifier)
, m_mode(mode)
, m_initialization_mode(initialization_mode)
{
}
ThrowCompletionOr<void> execute_impl(Bytecode::Interpreter&) const;
String to_string_impl(Bytecode::Executable const&) const;
void replace_references_impl(BasicBlock const&, BasicBlock const&) { }
private:
IdentifierTableIndex m_identifier;
EnvironmentMode m_mode;
InitializationMode m_initialization_mode { InitializationMode::Set };
};
class GetVariable final : public Instruction {
@ -599,6 +649,22 @@ private:
Optional<Label> m_finalizer_target;
};
class LeaveEnvironment final : public Instruction {
public:
LeaveEnvironment(EnvironmentMode mode)
: Instruction(Type::LeaveEnvironment)
, m_mode(mode)
{
}
ThrowCompletionOr<void> execute_impl(Bytecode::Interpreter&) const;
String to_string_impl(Bytecode::Executable const&) const;
void replace_references_impl(BasicBlock const&, BasicBlock const&) { }
private:
EnvironmentMode m_mode { EnvironmentMode::Lexical };
};
class LeaveUnwindContext final : public Instruction {
public:
LeaveUnwindContext()