Factor out ActionStack from Interpreter (#951)

This commit is contained in:
Geoff Romer
2021-11-17 12:59:16 -08:00
committed by GitHub
parent 7a5b8434c8
commit 9642d7ad05
5 changed files with 437 additions and 351 deletions
+167 -275
View File
@@ -42,16 +42,7 @@ void Interpreter::PrintEnv(Env values, llvm::raw_ostream& out) {
// State Operations
//
auto Interpreter::CurrentScope() -> Scope& {
for (const std::unique_ptr<Action>& action : todo_) {
if (action->scope().has_value()) {
return *action->scope();
}
}
FATAL() << "No current scope";
}
auto Interpreter::CurrentEnv() -> Env { return CurrentScope().values(); }
auto Interpreter::CurrentEnv() -> Env { return todo_.CurrentScope().values(); }
// Returns the given name from the environment, printing an error if not found.
auto Interpreter::GetFromEnv(SourceLocation source_loc, const std::string& name)
@@ -64,11 +55,7 @@ auto Interpreter::GetFromEnv(SourceLocation source_loc, const std::string& name)
}
void Interpreter::PrintState(llvm::raw_ostream& out) {
out << "{\nstack: ";
llvm::ListSeparator sep(" :: ");
for (const std::unique_ptr<Action>& action : todo_) {
out << sep << *action;
}
out << "{\nstack: " << todo_;
out << "\nheap: " << heap_;
if (!todo_.IsEmpty()) {
out << "\nvalues: ";
@@ -355,8 +342,8 @@ void Interpreter::PatternAssignment(Nonnull<const Value*> pat,
}
}
auto Interpreter::StepLvalue() -> Transition {
Action& act = *todo_.Top();
void Interpreter::StepLvalue() {
Action& act = todo_.CurrentAction();
const Expression& exp = cast<LValAction>(act).expression();
if (trace_) {
llvm::outs() << "--- step lvalue " << exp << " (" << exp.source_loc()
@@ -369,33 +356,33 @@ auto Interpreter::StepLvalue() -> Transition {
Address pointer =
GetFromEnv(exp.source_loc(), cast<IdentifierExpression>(exp).name());
Nonnull<const Value*> v = arena_->New<PointerValue>(pointer);
return Done{v};
return todo_.FinishAction(v);
}
case ExpressionKind::FieldAccessExpression: {
if (act.pos() == 0) {
// { {e.f :: C, E, F} :: S, H}
// -> { e :: [].f :: C, E, F} :: S, H}
return Spawn{std::make_unique<LValAction>(
&cast<FieldAccessExpression>(exp).aggregate())};
return todo_.Spawn(std::make_unique<LValAction>(
&cast<FieldAccessExpression>(exp).aggregate()));
} else {
// { v :: [].f :: C, E, F} :: S, H}
// -> { { &v.f :: C, E, F} :: S, H }
Address aggregate = cast<PointerValue>(*act.results()[0]).value();
Address field = aggregate.SubobjectAddress(
cast<FieldAccessExpression>(exp).field());
return Done{arena_->New<PointerValue>(field)};
return todo_.FinishAction(arena_->New<PointerValue>(field));
}
}
case ExpressionKind::IndexExpression: {
if (act.pos() == 0) {
// { {e[i] :: C, E, F} :: S, H}
// -> { e :: [][i] :: C, E, F} :: S, H}
return Spawn{std::make_unique<LValAction>(
&cast<IndexExpression>(exp).aggregate())};
return todo_.Spawn(std::make_unique<LValAction>(
&cast<IndexExpression>(exp).aggregate()));
} else if (act.pos() == 1) {
return Spawn{std::make_unique<ExpressionAction>(
&cast<IndexExpression>(exp).offset())};
return todo_.Spawn(std::make_unique<ExpressionAction>(
&cast<IndexExpression>(exp).offset()));
} else {
// { v :: [][i] :: C, E, F} :: S, H}
// -> { { &v[i] :: C, E, F} :: S, H }
@@ -403,7 +390,7 @@ auto Interpreter::StepLvalue() -> Transition {
std::string f =
std::to_string(cast<IntValue>(*act.results()[1]).value());
Address field = aggregate.SubobjectAddress(f);
return Done{arena_->New<PointerValue>(field)};
return todo_.FinishAction(arena_->New<PointerValue>(field));
}
}
case ExpressionKind::TupleLiteral: {
@@ -413,10 +400,10 @@ auto Interpreter::StepLvalue() -> Transition {
// H}
// -> { { ek+1 :: (f1=v1,..., fk=vk, fk+1=[],...) :: C, E, F} :: S,
// H}
return Spawn{std::make_unique<LValAction>(
cast<TupleLiteral>(exp).fields()[act.pos()])};
return todo_.Spawn(std::make_unique<LValAction>(
cast<TupleLiteral>(exp).fields()[act.pos()]));
} else {
return Done{arena_->New<TupleValue>(act.results())};
return todo_.FinishAction(arena_->New<TupleValue>(act.results()));
}
}
case ExpressionKind::StructLiteral:
@@ -505,8 +492,8 @@ auto Interpreter::Convert(Nonnull<const Value*> value,
}
}
auto Interpreter::StepExp() -> Transition {
Action& act = *todo_.Top();
void Interpreter::StepExp() {
Action& act = todo_.CurrentAction();
const Expression& exp = cast<ExpressionAction>(act).expression();
if (trace_) {
llvm::outs() << "--- step exp " << exp << " (" << exp.source_loc()
@@ -517,11 +504,11 @@ auto Interpreter::StepExp() -> Transition {
if (act.pos() == 0) {
// { { e[i] :: C, E, F} :: S, H}
// -> { { e :: [][i] :: C, E, F} :: S, H}
return Spawn{std::make_unique<ExpressionAction>(
&cast<IndexExpression>(exp).aggregate())};
return todo_.Spawn(std::make_unique<ExpressionAction>(
&cast<IndexExpression>(exp).aggregate()));
} else if (act.pos() == 1) {
return Spawn{std::make_unique<ExpressionAction>(
&cast<IndexExpression>(exp).offset())};
return todo_.Spawn(std::make_unique<ExpressionAction>(
&cast<IndexExpression>(exp).offset()));
} else {
// { { v :: [][i] :: C, E, F} :: S, H}
// -> { { v_i :: C, E, F} : S, H}
@@ -531,7 +518,7 @@ auto Interpreter::StepExp() -> Transition {
FATAL_RUNTIME_ERROR_NO_LINE()
<< "index " << i << " out of range in " << tuple;
}
return Done{tuple.elements()[i]};
return todo_.FinishAction(tuple.elements()[i]);
}
}
case ExpressionKind::TupleLiteral: {
@@ -541,32 +528,33 @@ auto Interpreter::StepExp() -> Transition {
// H}
// -> { { ek+1 :: (f1=v1,..., fk=vk, fk+1=[],...) :: C, E, F} :: S,
// H}
return Spawn{std::make_unique<ExpressionAction>(
cast<TupleLiteral>(exp).fields()[act.pos()])};
return todo_.Spawn(std::make_unique<ExpressionAction>(
cast<TupleLiteral>(exp).fields()[act.pos()]));
} else {
return Done{arena_->New<TupleValue>(act.results())};
return todo_.FinishAction(arena_->New<TupleValue>(act.results()));
}
}
case ExpressionKind::StructLiteral: {
const auto& literal = cast<StructLiteral>(exp);
if (act.pos() < static_cast<int>(literal.fields().size())) {
return Spawn{std::make_unique<ExpressionAction>(
&literal.fields()[act.pos()].expression())};
return todo_.Spawn(std::make_unique<ExpressionAction>(
&literal.fields()[act.pos()].expression()));
} else {
return Done{CreateStruct(literal.fields(), act.results())};
return todo_.FinishAction(
CreateStruct(literal.fields(), act.results()));
}
}
case ExpressionKind::StructTypeLiteral: {
const auto& struct_type = cast<StructTypeLiteral>(exp);
if (act.pos() < static_cast<int>(struct_type.fields().size())) {
return Spawn{std::make_unique<ExpressionAction>(
&struct_type.fields()[act.pos()].expression())};
return todo_.Spawn(std::make_unique<ExpressionAction>(
&struct_type.fields()[act.pos()].expression()));
} else {
std::vector<NamedValue> fields;
for (size_t i = 0; i < struct_type.fields().size(); ++i) {
fields.push_back({struct_type.fields()[i].name(), act.results()[i]});
}
return Done{arena_->New<StructType>(std::move(fields))};
return todo_.FinishAction(arena_->New<StructType>(std::move(fields)));
}
}
case ExpressionKind::FieldAccessExpression: {
@@ -574,12 +562,13 @@ auto Interpreter::StepExp() -> Transition {
if (act.pos() == 0) {
// { { e.f :: C, E, F} :: S, H}
// -> { { e :: [].f :: C, E, F} :: S, H}
return Spawn{std::make_unique<ExpressionAction>(&access.aggregate())};
return todo_.Spawn(
std::make_unique<ExpressionAction>(&access.aggregate()));
} else {
// { { v :: [].f :: C, E, F} :: S, H}
// -> { { v_f :: C, E, F} : S, H}
return Done{act.results()[0]->GetField(
arena_, FieldPath(access.field()), exp.source_loc())};
return todo_.FinishAction(act.results()[0]->GetField(
arena_, FieldPath(access.field()), exp.source_loc()));
}
}
case ExpressionKind::IdentifierExpression: {
@@ -587,40 +576,43 @@ auto Interpreter::StepExp() -> Transition {
const auto& ident = cast<IdentifierExpression>(exp);
// { {x :: C, E, F} :: S, H} -> { {H(E(x)) :: C, E, F} :: S, H}
Address pointer = GetFromEnv(exp.source_loc(), ident.name());
return Done{heap_.Read(pointer, exp.source_loc())};
return todo_.FinishAction(heap_.Read(pointer, exp.source_loc()));
}
case ExpressionKind::IntLiteral:
CHECK(act.pos() == 0);
// { {n :: C, E, F} :: S, H} -> { {n' :: C, E, F} :: S, H}
return Done{arena_->New<IntValue>(cast<IntLiteral>(exp).value())};
return todo_.FinishAction(
arena_->New<IntValue>(cast<IntLiteral>(exp).value()));
case ExpressionKind::BoolLiteral:
CHECK(act.pos() == 0);
// { {n :: C, E, F} :: S, H} -> { {n' :: C, E, F} :: S, H}
return Done{arena_->New<BoolValue>(cast<BoolLiteral>(exp).value())};
return todo_.FinishAction(
arena_->New<BoolValue>(cast<BoolLiteral>(exp).value()));
case ExpressionKind::PrimitiveOperatorExpression: {
const auto& op = cast<PrimitiveOperatorExpression>(exp);
if (act.pos() != static_cast<int>(op.arguments().size())) {
// { {v :: op(vs,[],e,es) :: C, E, F} :: S, H}
// -> { {e :: op(vs,v,[],es) :: C, E, F} :: S, H}
Nonnull<const Expression*> arg = op.arguments()[act.pos()];
return Spawn{std::make_unique<ExpressionAction>(arg)};
return todo_.Spawn(std::make_unique<ExpressionAction>(arg));
} else {
// { {v :: op(vs,[]) :: C, E, F} :: S, H}
// -> { {eval_prim(op, (vs,v)) :: C, E, F} :: S, H}
return Done{EvalPrim(op.op(), act.results(), exp.source_loc())};
return todo_.FinishAction(
EvalPrim(op.op(), act.results(), exp.source_loc()));
}
}
case ExpressionKind::CallExpression:
if (act.pos() == 0) {
// { {e1(e2) :: C, E, F} :: S, H}
// -> { {e1 :: [](e2) :: C, E, F} :: S, H}
return Spawn{std::make_unique<ExpressionAction>(
&cast<CallExpression>(exp).function())};
return todo_.Spawn(std::make_unique<ExpressionAction>(
&cast<CallExpression>(exp).function()));
} else if (act.pos() == 1) {
// { { v :: [](e) :: C, E, F} :: S, H}
// -> { { e :: v([]) :: C, E, F} :: S, H}
return Spawn{std::make_unique<ExpressionAction>(
&cast<CallExpression>(exp).argument())};
return todo_.Spawn(std::make_unique<ExpressionAction>(
&cast<CallExpression>(exp).argument()));
} else if (act.pos() == 2) {
// { { v2 :: v1([]) :: C, E, F} :: S, H}
// -> { {C',E',F'} :: {C, E, F} :: S, H}
@@ -628,15 +620,29 @@ auto Interpreter::StepExp() -> Transition {
case Value::Kind::AlternativeConstructorValue: {
const auto& alt =
cast<AlternativeConstructorValue>(*act.results()[0]);
return Done{arena_->New<AlternativeValue>(
alt.alt_name(), alt.choice_name(), act.results()[1])};
return todo_.FinishAction(arena_->New<AlternativeValue>(
alt.alt_name(), alt.choice_name(), act.results()[1]));
}
case Value::Kind::FunctionValue: {
const FunctionDeclaration& function =
cast<FunctionValue>(*act.results()[0]).declaration();
Nonnull<const Value*> converted_args = Convert(
act.results()[1], &function.param_pattern().static_type());
std::optional<Env> matches =
PatternMatch(&function.param_pattern().value(), converted_args,
exp.source_loc());
CHECK(matches.has_value())
<< "internal error in call_function, pattern match failed";
Scope new_scope(globals_, &heap_);
for (const auto& [name, value] : *matches) {
new_scope.AddLocal(name, value);
}
CHECK(function.body().has_value())
<< "Calling a function that's missing a body";
return todo_.Spawn(
std::make_unique<StatementAction>(*function.body()),
std::move(new_scope));
}
case Value::Kind::FunctionValue:
return CallFunction{
.function =
&cast<FunctionValue>(*act.results()[0]).declaration(),
.args = act.results()[1],
.source_loc = exp.source_loc()};
default:
FATAL_RUNTIME_ERROR(exp.source_loc())
<< "in call, expected a function, not " << *act.results()[0];
@@ -644,9 +650,9 @@ auto Interpreter::StepExp() -> Transition {
} else if (act.pos() == 3) {
if (act.results().size() < 3) {
// Control fell through without explicit return.
return Done{TupleValue::Empty()};
return todo_.FinishAction(TupleValue::Empty());
} else {
return Done{act.results()[2]};
return todo_.FinishAction(act.results()[2]);
}
} else {
FATAL() << "in handle_value with Call pos " << act.pos();
@@ -661,55 +667,56 @@ auto Interpreter::StepExp() -> Transition {
CHECK(pointee->kind() == Value::Kind::StringValue);
// TODO: This could eventually use something like llvm::formatv.
llvm::outs() << cast<StringValue>(*pointee).value();
return Done{TupleValue::Empty()};
return todo_.FinishAction(TupleValue::Empty());
}
case ExpressionKind::IntTypeLiteral: {
CHECK(act.pos() == 0);
return Done{arena_->New<IntType>()};
return todo_.FinishAction(arena_->New<IntType>());
}
case ExpressionKind::BoolTypeLiteral: {
CHECK(act.pos() == 0);
return Done{arena_->New<BoolType>()};
return todo_.FinishAction(arena_->New<BoolType>());
}
case ExpressionKind::TypeTypeLiteral: {
CHECK(act.pos() == 0);
return Done{arena_->New<TypeType>()};
return todo_.FinishAction(arena_->New<TypeType>());
}
case ExpressionKind::FunctionTypeLiteral: {
if (act.pos() == 0) {
return Spawn{std::make_unique<ExpressionAction>(
&cast<FunctionTypeLiteral>(exp).parameter())};
return todo_.Spawn(std::make_unique<ExpressionAction>(
&cast<FunctionTypeLiteral>(exp).parameter()));
} else if (act.pos() == 1) {
// { { pt :: fn [] -> e :: C, E, F} :: S, H}
// -> { { e :: fn pt -> []) :: C, E, F} :: S, H}
return Spawn{std::make_unique<ExpressionAction>(
&cast<FunctionTypeLiteral>(exp).return_type())};
return todo_.Spawn(std::make_unique<ExpressionAction>(
&cast<FunctionTypeLiteral>(exp).return_type()));
} else {
// { { rt :: fn pt -> [] :: C, E, F} :: S, H}
// -> { fn pt -> rt :: {C, E, F} :: S, H}
return Done{arena_->New<FunctionType>(
return todo_.FinishAction(arena_->New<FunctionType>(
std::vector<Nonnull<const GenericBinding*>>(), act.results()[0],
act.results()[1])};
act.results()[1]));
}
}
case ExpressionKind::ContinuationTypeLiteral: {
CHECK(act.pos() == 0);
return Done{arena_->New<ContinuationType>()};
return todo_.FinishAction(arena_->New<ContinuationType>());
}
case ExpressionKind::StringLiteral:
CHECK(act.pos() == 0);
// { {n :: C, E, F} :: S, H} -> { {n' :: C, E, F} :: S, H}
return Done{arena_->New<StringValue>(cast<StringLiteral>(exp).value())};
return todo_.FinishAction(
arena_->New<StringValue>(cast<StringLiteral>(exp).value()));
case ExpressionKind::StringTypeLiteral: {
CHECK(act.pos() == 0);
return Done{arena_->New<StringType>()};
return todo_.FinishAction(arena_->New<StringType>());
}
} // switch (exp->kind)
}
auto Interpreter::StepPattern() -> Transition {
Action& act = *todo_.Top();
void Interpreter::StepPattern() {
Action& act = todo_.CurrentAction();
const Pattern& pattern = cast<PatternAction>(act).pattern();
if (trace_) {
llvm::outs() << "--- step pattern " << pattern << " ("
@@ -718,15 +725,15 @@ auto Interpreter::StepPattern() -> Transition {
switch (pattern.kind()) {
case PatternKind::AutoPattern: {
CHECK(act.pos() == 0);
return Done{arena_->New<AutoType>()};
return todo_.FinishAction(arena_->New<AutoType>());
}
case PatternKind::BindingPattern: {
const auto& binding = cast<BindingPattern>(pattern);
if (act.pos() == 0) {
return Spawn{std::make_unique<PatternAction>(&binding.type())};
return todo_.Spawn(std::make_unique<PatternAction>(&binding.type()));
} else {
return Done{arena_->New<BindingPlaceholderValue>(binding.name(),
act.results()[0])};
return todo_.FinishAction(arena_->New<BindingPlaceholderValue>(
binding.name(), act.results()[0]));
}
}
case PatternKind::TuplePattern: {
@@ -736,40 +743,40 @@ auto Interpreter::StepPattern() -> Transition {
// H}
// -> { { ek+1 :: (f1=v1,..., fk=vk, fk+1=[],...) :: C, E, F} :: S,
// H}
return Spawn{
std::make_unique<PatternAction>(tuple.fields()[act.pos()])};
return todo_.Spawn(
std::make_unique<PatternAction>(tuple.fields()[act.pos()]));
} else {
return Done{arena_->New<TupleValue>(act.results())};
return todo_.FinishAction(arena_->New<TupleValue>(act.results()));
}
}
case PatternKind::AlternativePattern: {
const auto& alternative = cast<AlternativePattern>(pattern);
if (act.pos() == 0) {
return Spawn{
std::make_unique<ExpressionAction>(&alternative.choice_type())};
return todo_.Spawn(
std::make_unique<ExpressionAction>(&alternative.choice_type()));
} else if (act.pos() == 1) {
return Spawn{std::make_unique<PatternAction>(&alternative.arguments())};
return todo_.Spawn(
std::make_unique<PatternAction>(&alternative.arguments()));
} else {
CHECK(act.pos() == 2);
const auto& choice_type = cast<ChoiceType>(*act.results()[0]);
return Done{arena_->New<AlternativeValue>(
return todo_.FinishAction(arena_->New<AlternativeValue>(
alternative.alternative_name(), choice_type.name(),
act.results()[1])};
act.results()[1]));
}
}
case PatternKind::ExpressionPattern:
return Delegate{std::make_unique<ExpressionAction>(
&cast<ExpressionPattern>(pattern).expression())};
if (act.pos() == 0) {
return todo_.Spawn(std::make_unique<ExpressionAction>(
&cast<ExpressionPattern>(pattern).expression()));
} else {
return todo_.FinishAction(act.results()[0]);
}
}
}
static auto IsRunAction(const Action& action) -> bool {
const auto* statement = dyn_cast<StatementAction>(&action);
return statement != nullptr && llvm::isa<Run>(statement->statement());
}
auto Interpreter::StepStmt() -> Transition {
Action& act = *todo_.Top();
void Interpreter::StepStmt() {
Action& act = todo_.CurrentAction();
const Statement& stmt = cast<StatementAction>(act).statement();
if (trace_) {
llvm::outs() << "--- step stmt ";
@@ -783,12 +790,12 @@ auto Interpreter::StepStmt() -> Transition {
// { { (match (e) ...) :: C, E, F} :: S, H}
// -> { { e :: (match ([]) ...) :: C, E, F} :: S, H}
act.StartScope(Scope(CurrentEnv(), &heap_));
return Spawn{
std::make_unique<ExpressionAction>(&match_stmt.expression())};
return todo_.Spawn(
std::make_unique<ExpressionAction>(&match_stmt.expression()));
} else {
int clause_num = act.pos() - 1;
if (clause_num >= static_cast<int>(match_stmt.clauses().size())) {
return Done{};
return todo_.FinishAction();
}
auto c = match_stmt.clauses()[clause_num];
std::optional<Env> matches =
@@ -802,9 +809,9 @@ auto Interpreter::StepStmt() -> Transition {
for (const auto& [name, value] : *matches) {
act.scope()->AddLocal(name, value);
}
return Spawn{std::make_unique<StatementAction>(&c.statement())};
return todo_.Spawn(std::make_unique<StatementAction>(&c.statement()));
} else {
return RunAgain{};
return todo_.RunAgain();
}
}
}
@@ -813,40 +820,40 @@ auto Interpreter::StepStmt() -> Transition {
// { { (while (e) s) :: C, E, F} :: S, H}
// -> { { e :: (while ([]) s) :: C, E, F} :: S, H}
act.Clear();
return Spawn{
std::make_unique<ExpressionAction>(&cast<While>(stmt).condition())};
return todo_.Spawn(
std::make_unique<ExpressionAction>(&cast<While>(stmt).condition()));
} else {
Nonnull<const Value*> condition =
Convert(act.results().back(), arena_->New<BoolType>());
if (cast<BoolValue>(*condition).value()) {
// { {true :: (while ([]) s) :: C, E, F} :: S, H}
// -> { { s :: (while (e) s) :: C, E, F } :: S, H}
return Spawn{
std::make_unique<StatementAction>(&cast<While>(stmt).body())};
return todo_.Spawn(
std::make_unique<StatementAction>(&cast<While>(stmt).body()));
} else {
// { {false :: (while ([]) s) :: C, E, F} :: S, H}
// -> { { C, E, F } :: S, H}
return Done{};
return todo_.FinishAction();
}
}
case StatementKind::Break: {
CHECK(act.pos() == 0);
// { { break; :: ... :: (while (e) s) :: C, E, F} :: S, H}
// -> { { C, E', F} :: S, H}
return UnwindPast{.ast_node = &cast<Break>(stmt).loop()};
return todo_.UnwindPast(&cast<Break>(stmt).loop());
}
case StatementKind::Continue: {
CHECK(act.pos() == 0);
// { { continue; :: ... :: (while (e) s) :: C, E, F} :: S, H}
// -> { { (while (e) s) :: C, E', F} :: S, H}
return UnwindTo{.ast_node = &cast<Continue>(stmt).loop()};
return todo_.UnwindTo(&cast<Continue>(stmt).loop());
}
case StatementKind::Block: {
const auto& block = cast<Block>(stmt);
if (act.pos() >= static_cast<int>(block.statements().size())) {
// If the position is past the end of the block, end processing. Note
// that empty blocks immediately end.
return Done{};
return todo_.FinishAction();
}
// Initialize a scope when starting a block.
if (act.pos() == 0) {
@@ -854,15 +861,16 @@ auto Interpreter::StepStmt() -> Transition {
}
// Process the next statement in the block. The position will be
// incremented as part of Spawn.
return Spawn{
std::make_unique<StatementAction>(block.statements()[act.pos()])};
return todo_.Spawn(
std::make_unique<StatementAction>(block.statements()[act.pos()]));
}
case StatementKind::VariableDefinition: {
const auto& definition = cast<VariableDefinition>(stmt);
if (act.pos() == 0) {
// { {(var x = e) :: C, E, F} :: S, H}
// -> { {e :: (var x = []) :: C, E, F} :: S, H}
return Spawn{std::make_unique<ExpressionAction>(&definition.init())};
return todo_.Spawn(
std::make_unique<ExpressionAction>(&definition.init()));
} else {
// { { v :: (x = []) :: C, E, F} :: S, H}
// -> { { C, E(x := a), F} :: S, H(a := copy(v))}
@@ -876,79 +884,80 @@ auto Interpreter::StepStmt() -> Transition {
<< stmt.source_loc()
<< ": internal error in variable definition, match failed";
for (const auto& [name, value] : *matches) {
Scope& current_scope = CurrentScope();
Scope& current_scope = todo_.CurrentScope();
current_scope.AddLocal(name, value);
}
return Done{};
return todo_.FinishAction();
}
}
case StatementKind::ExpressionStatement:
if (act.pos() == 0) {
// { {e :: C, E, F} :: S, H}
// -> { {e :: C, E, F} :: S, H}
return Spawn{std::make_unique<ExpressionAction>(
&cast<ExpressionStatement>(stmt).expression())};
return todo_.Spawn(std::make_unique<ExpressionAction>(
&cast<ExpressionStatement>(stmt).expression()));
} else {
return Done{};
return todo_.FinishAction();
}
case StatementKind::Assign: {
const auto& assign = cast<Assign>(stmt);
if (act.pos() == 0) {
// { {(lv = e) :: C, E, F} :: S, H}
// -> { {lv :: ([] = e) :: C, E, F} :: S, H}
return Spawn{std::make_unique<LValAction>(&assign.lhs())};
return todo_.Spawn(std::make_unique<LValAction>(&assign.lhs()));
} else if (act.pos() == 1) {
// { { a :: ([] = e) :: C, E, F} :: S, H}
// -> { { e :: (a = []) :: C, E, F} :: S, H}
return Spawn{std::make_unique<ExpressionAction>(&assign.rhs())};
return todo_.Spawn(std::make_unique<ExpressionAction>(&assign.rhs()));
} else {
// { { v :: (a = []) :: C, E, F} :: S, H}
// -> { { C, E, F} :: S, H(a := v)}
auto pat = act.results()[0];
auto val = Convert(act.results()[1], &assign.lhs().static_type());
PatternAssignment(pat, val, stmt.source_loc());
return Done{};
return todo_.FinishAction();
}
}
case StatementKind::If:
if (act.pos() == 0) {
// { {(if (e) then_stmt else else_stmt) :: C, E, F} :: S, H}
// -> { { e :: (if ([]) then_stmt else else_stmt) :: C, E, F} :: S, H}
return Spawn{
std::make_unique<ExpressionAction>(&cast<If>(stmt).condition())};
} else {
return todo_.Spawn(
std::make_unique<ExpressionAction>(&cast<If>(stmt).condition()));
} else if (act.pos() == 1) {
Nonnull<const Value*> condition =
Convert(act.results()[0], arena_->New<BoolType>());
if (cast<BoolValue>(*condition).value()) {
// { {true :: if ([]) then_stmt else else_stmt :: C, E, F} ::
// S, H}
// -> { { then_stmt :: C, E, F } :: S, H}
return Delegate{
std::make_unique<StatementAction>(&cast<If>(stmt).then_block())};
return todo_.Spawn(
std::make_unique<StatementAction>(&cast<If>(stmt).then_block()));
} else if (cast<If>(stmt).else_block()) {
// { {false :: if ([]) then_stmt else else_stmt :: C, E, F} ::
// S, H}
// -> { { else_stmt :: C, E, F } :: S, H}
return Delegate{
std::make_unique<StatementAction>(*cast<If>(stmt).else_block())};
return todo_.Spawn(
std::make_unique<StatementAction>(*cast<If>(stmt).else_block()));
} else {
return Done{};
return todo_.FinishAction();
}
} else {
return todo_.FinishAction();
}
case StatementKind::Return:
if (act.pos() == 0) {
// { {return e :: C, E, F} :: S, H}
// -> { {e :: return [] :: C, E, F} :: S, H}
return Spawn{std::make_unique<ExpressionAction>(
&cast<Return>(stmt).expression())};
return todo_.Spawn(std::make_unique<ExpressionAction>(
&cast<Return>(stmt).expression()));
} else {
// { {v :: return [] :: C, E, F} :: {C', E', F'} :: S, H}
// -> { {v :: C', E', F'} :: S, H}
const FunctionDeclaration& function = cast<Return>(stmt).function();
return UnwindPast{
.ast_node = *function.body(),
.result = Convert(act.results()[0],
&function.return_term().static_type())};
return todo_.UnwindPast(
*function.body(),
Convert(act.results()[0], &function.return_term().static_type()));
}
case StatementKind::Continuation: {
CHECK(act.pos() == 0);
@@ -965,171 +974,55 @@ auto Interpreter::StepStmt() -> Transition {
AllocationId continuation_address =
heap_.AllocateValue(arena_->New<ContinuationValue>(fragment));
// Bind the continuation object to the continuation variable
CurrentScope().AddLocal(cast<Continuation>(stmt).continuation_variable(),
continuation_address);
return Done{};
todo_.CurrentScope().AddLocal(
cast<Continuation>(stmt).continuation_variable(),
continuation_address);
return todo_.FinishAction();
}
case StatementKind::Run: {
auto& run = cast<Run>(stmt);
if (act.pos() == 0) {
// Evaluate the argument of the run statement.
return Spawn{std::make_unique<ExpressionAction>(&run.argument())};
return todo_.Spawn(std::make_unique<ExpressionAction>(&run.argument()));
} else if (act.pos() == 1) {
// Push the continuation onto the current stack.
cast<const ContinuationValue>(*act.results()[0])
.stack()
.RestoreTo(todo_);
act.set_pos(2);
return ManualTransition{};
return todo_.Resume(cast<const ContinuationValue>(act.results()[0]));
} else {
return Done{};
return todo_.FinishAction();
}
}
case StatementKind::Await:
CHECK(act.pos() == 0);
// Pause the current continuation
todo_.Pop();
std::vector<std::unique_ptr<Action>> paused;
while (!IsRunAction(*todo_.Top())) {
paused.push_back(todo_.Pop());
}
const auto& continuation =
cast<const ContinuationValue>(*todo_.Top()->results()[0]);
// Update the continuation with the paused stack.
continuation.stack().StoreReversed(std::move(paused));
return ManualTransition{};
return todo_.Suspend();
}
}
class Interpreter::DoTransition {
public:
// Does not take ownership of interpreter.
explicit DoTransition(Interpreter* interpreter) : interpreter(interpreter) {}
void operator()(const Done& done) {
std::unique_ptr<Action> act = interpreter->todo_.Pop();
switch (act->kind()) {
case Action::Kind::ExpressionAction:
case Action::Kind::LValAction:
case Action::Kind::PatternAction:
CHECK(done.result.has_value());
interpreter->todo_.Top()->AddResult(*done.result);
break;
case Action::Kind::StatementAction:
CHECK(!done.result.has_value());
break;
case Action::Kind::ScopeAction:
if (done.result.has_value()) {
interpreter->todo_.Top()->AddResult(*done.result);
}
break;
}
}
void operator()(Spawn spawn) {
Action& action = *interpreter->todo_.Top();
action.set_pos(action.pos() + 1);
interpreter->todo_.Push(std::move(spawn.child));
}
void operator()(Delegate delegate) {
std::unique_ptr<Action> act = interpreter->todo_.Pop();
if (act->scope().has_value()) {
delegate.delegate->StartScope(std::move(*act->scope()));
}
interpreter->todo_.Push(std::move(delegate.delegate));
}
void operator()(const RunAgain&) {
Action& action = *interpreter->todo_.Top();
action.set_pos(action.pos() + 1);
}
void operator()(const UnwindTo& unwind_to) { DoUnwindTo(unwind_to.ast_node); }
void operator()(const UnwindPast& unwind_past) {
DoUnwindTo(unwind_past.ast_node);
// Unwind past the statement and return a result if needed.
interpreter->todo_.Pop();
if (unwind_past.result.has_value()) {
interpreter->todo_.Top()->AddResult(*unwind_past.result);
}
}
void operator()(const CallFunction& call) {
Action& action = *interpreter->todo_.Top();
action.set_pos(action.pos() + 1);
Nonnull<const Value*> converted_args = interpreter->Convert(
call.args, &call.function->param_pattern().static_type());
std::optional<Env> matches =
interpreter->PatternMatch(&call.function->param_pattern().value(),
converted_args, call.source_loc);
CHECK(matches.has_value())
<< "internal error in call_function, pattern match failed";
// Create the new frame and push it on the stack
Scope new_scope(interpreter->globals_, &interpreter->heap_);
for (const auto& [name, value] : *matches) {
new_scope.AddLocal(name, value);
}
interpreter->todo_.Push(
std::make_unique<ScopeAction>(std::move(new_scope)));
CHECK(call.function->body()) << "Calling a function that's missing a body";
interpreter->todo_.Push(
std::make_unique<StatementAction>(*call.function->body()));
}
void operator()(const ManualTransition&) {}
private:
// Unwinds to the indicated node.
void DoUnwindTo(Nonnull<const Statement*> ast_node) {
while (true) {
if (const auto* statement_action =
dyn_cast<StatementAction>(interpreter->todo_.Top().get());
statement_action != nullptr &&
&statement_action->statement() == ast_node) {
break;
}
interpreter->todo_.Pop();
}
}
Nonnull<Interpreter*> interpreter;
};
// State transition.
void Interpreter::Step() {
Action& act = *todo_.Top();
Action& act = todo_.CurrentAction();
switch (act.kind()) {
case Action::Kind::LValAction:
std::visit(DoTransition(this), StepLvalue());
StepLvalue();
break;
case Action::Kind::ExpressionAction:
std::visit(DoTransition(this), StepExp());
StepExp();
break;
case Action::Kind::PatternAction:
std::visit(DoTransition(this), StepPattern());
StepPattern();
break;
case Action::Kind::StatementAction:
std::visit(DoTransition(this), StepStmt());
StepStmt();
break;
case Action::Kind::ScopeAction:
if (act.results().empty()) {
std::visit(DoTransition(this), Transition{Done{}});
} else {
CHECK(act.results().size() == 1);
std::visit(DoTransition(this), Transition{Done{act.results()[0]}});
}
FATAL() << "ScopeAction escaped ActionStack";
} // switch
}
auto Interpreter::ExecuteAction(std::unique_ptr<Action> action, Env values,
bool trace_steps) -> Nonnull<const Value*> {
todo_ = {};
todo_.Push(std::make_unique<ScopeAction>(Scope(values, &heap_)));
todo_.Push(std::move(action));
todo_.Start(std::move(action), Scope(values, &heap_));
while (todo_.Count() > 1) {
while (!todo_.IsEmpty()) {
Step();
if (trace_steps) {
PrintState(llvm::outs());
@@ -1141,8 +1034,7 @@ auto Interpreter::ExecuteAction(std::unique_ptr<Action> action, Env values,
fragment->Clear();
}
CHECK(todo_.Top()->results().size() == 1);
return todo_.Top()->results()[0];
return todo_.result();
}
auto Interpreter::InterpProgram(llvm::ArrayRef<Nonnull<Declaration*>> fs,