LibJS: Make Executable ref-counted and let instruction iterator co-own it

This ensures that the instruction stream pointed at by the instruction
iterator remains valid as long as the iterator exists.

Userland/Libraries/LibJS/Bytecode/Executable.cpp

@@ -5,9 +5,34 @@
  */
 
 #include <LibJS/Bytecode/Executable.h>
+#include <LibJS/SourceCode.h>
 
 namespace JS::Bytecode {
 
+Executable::Executable(
+    NonnullOwnPtr<IdentifierTable> identifier_table,
+    NonnullOwnPtr<StringTable> string_table,
+    NonnullOwnPtr<RegexTable> regex_table,
+    NonnullRefPtr<SourceCode const> source_code,
+    size_t number_of_property_lookup_caches,
+    size_t number_of_global_variable_caches,
+    size_t number_of_registers,
+    Vector<NonnullOwnPtr<BasicBlock>> basic_blocks,
+    bool is_strict_mode)
+    : basic_blocks(move(basic_blocks))
+    , string_table(move(string_table))
+    , identifier_table(move(identifier_table))
+    , regex_table(move(regex_table))
+    , source_code(move(source_code))
+    , number_of_registers(number_of_registers)
+    , is_strict_mode(is_strict_mode)
+{
+    property_lookup_caches.resize(number_of_property_lookup_caches);
+    global_variable_caches.resize(number_of_global_variable_caches);
+}
+
+Executable::~Executable() = default;
+
 void Executable::dump() const
 {
     dbgln("\033[33;1mJS::Bytecode::Executable\033[0m ({})", name);

Userland/Libraries/LibJS/Bytecode/Executable.h

@@ -31,7 +31,21 @@ struct SourceRecord {
     u32 source_end_offset {};
 };
 
-struct Executable {
+class Executable final : public RefCounted<Executable> {
+public:
+    Executable(
+        NonnullOwnPtr<IdentifierTable>,
+        NonnullOwnPtr<StringTable>,
+        NonnullOwnPtr<RegexTable>,
+        NonnullRefPtr<SourceCode const>,
+        size_t number_of_property_lookup_caches,
+        size_t number_of_global_variable_caches,
+        size_t number_of_registers,
+        Vector<NonnullOwnPtr<BasicBlock>>,
+        bool is_strict_mode);
+
+    ~Executable();
+
     DeprecatedFlyString name;
     Vector<PropertyLookupCache> property_lookup_caches;
     Vector<GlobalVariableCache> global_variable_caches;

Userland/Libraries/LibJS/Bytecode/Generator.cpp

@@ -20,7 +20,7 @@ Generator::Generator()
 {
 }
 
-CodeGenerationErrorOr<NonnullOwnPtr<Executable>> Generator::generate(ASTNode const& node, FunctionKind enclosing_function_kind)
+CodeGenerationErrorOr<NonnullRefPtr<Executable>> Generator::generate(ASTNode const& node, FunctionKind enclosing_function_kind)
 {
     Generator generator;
     generator.switch_to_basic_block(generator.make_block());
@@ -56,24 +56,18 @@ CodeGenerationErrorOr<NonnullOwnPtr<Executable>> Generator::generate(ASTNode con
     else if (is<FunctionExpression>(node))
         is_strict_mode = static_cast<FunctionExpression const&>(node).is_strict_mode();
 
-    Vector<PropertyLookupCache> property_lookup_caches;
-    property_lookup_caches.resize(generator.m_next_property_lookup_cache);
+    auto executable = adopt_ref(*new Executable(
+        move(generator.m_identifier_table),
+        move(generator.m_string_table),
+        move(generator.m_regex_table),
+        node.source_code(),
+        generator.m_next_property_lookup_cache,
+        generator.m_next_global_variable_cache,
+        generator.m_next_register,
+        move(generator.m_root_basic_blocks),
+        is_strict_mode));
 
-    Vector<GlobalVariableCache> global_variable_caches;
-    global_variable_caches.resize(generator.m_next_global_variable_cache);
-
-    return adopt_own(*new Executable {
-        .name = {},
-        .property_lookup_caches = move(property_lookup_caches),
-        .global_variable_caches = move(global_variable_caches),
-        .basic_blocks = move(generator.m_root_basic_blocks),
-        .string_table = move(generator.m_string_table),
-        .identifier_table = move(generator.m_identifier_table),
-        .regex_table = move(generator.m_regex_table),
-        .source_code = node.source_code(),
-        .number_of_registers = generator.m_next_register,
-        .is_strict_mode = is_strict_mode,
-    });
+    return executable;
 }
 
 void Generator::grow(size_t additional_size)

Userland/Libraries/LibJS/Bytecode/Generator.h

@@ -30,7 +30,7 @@ public:
         Function,
         Block,
     };
-    static CodeGenerationErrorOr<NonnullOwnPtr<Executable>> generate(ASTNode const&, FunctionKind = FunctionKind::Normal);
+    static CodeGenerationErrorOr<NonnullRefPtr<Executable>> generate(ASTNode const&, FunctionKind = FunctionKind::Normal);
 
     Register allocate_register();
 

Userland/Libraries/LibJS/Bytecode/Instruction.h

@@ -178,13 +178,15 @@ public:
     UnrealizedSourceRange source_range() const;
     RefPtr<SourceCode> source_code() const;
 
+    Executable const* executable() const { return m_executable; }
+
 private:
     Instruction const& dereference() const { return *reinterpret_cast<Instruction const*>(m_ptr); }
 
     u8 const* m_begin { nullptr };
     u8 const* m_end { nullptr };
     u8 const* m_ptr { nullptr };
-    Executable const* m_executable { nullptr };
+    RefPtr<Executable const> m_executable;
 };
 
 }

Userland/Libraries/LibJS/Bytecode/Interpreter.cpp

@@ -407,7 +407,7 @@ void Interpreter::leave_unwind_context()
     unwind_contexts().take_last();
 }
 
-ThrowCompletionOr<NonnullOwnPtr<Bytecode::Executable>> compile(VM& vm, ASTNode const& node, FunctionKind kind, DeprecatedFlyString const& name)
+ThrowCompletionOr<NonnullRefPtr<Bytecode::Executable>> compile(VM& vm, ASTNode const& node, FunctionKind kind, DeprecatedFlyString const& name)
 {
     auto executable_result = Bytecode::Generator::generate(node, kind);
     if (executable_result.is_error())

Userland/Libraries/LibJS/Bytecode/Interpreter.h

@@ -110,6 +110,6 @@ private:
 
 extern bool g_dump_bytecode;
 
-ThrowCompletionOr<NonnullOwnPtr<Bytecode::Executable>> compile(VM&, ASTNode const& no, JS::FunctionKind kind, DeprecatedFlyString const& name);
+ThrowCompletionOr<NonnullRefPtr<Bytecode::Executable>> compile(VM&, ASTNode const& no, JS::FunctionKind kind, DeprecatedFlyString const& name);
 
 }

Userland/Libraries/LibJS/Forward.h

@@ -302,7 +302,7 @@ class MarkedVector;
 
 namespace Bytecode {
 class BasicBlock;
-struct Executable;
+class Executable;
 class Generator;
 class Instruction;
 class Interpreter;

Userland/Libraries/LibJS/Runtime/ECMAScriptFunctionObject.h

@@ -111,8 +111,8 @@ private:
     ThrowCompletionOr<void> function_declaration_instantiation();
 
     DeprecatedFlyString m_name;
-    OwnPtr<Bytecode::Executable> m_bytecode_executable;
-    Vector<OwnPtr<Bytecode::Executable>> m_default_parameter_bytecode_executables;
+    RefPtr<Bytecode::Executable> m_bytecode_executable;
+    Vector<NonnullRefPtr<Bytecode::Executable>> m_default_parameter_bytecode_executables;
     i32 m_function_length { 0 };
     Vector<DeprecatedFlyString> m_local_variables_names;