mirror of
https://github.com/carbon-language/carbon-lang.git
synced 2026-09-25 20:30:14 +01:00
Geoff Romer
d177a08e01
Prior to this change, `__await` would make a deep copy of the continuation stack, but shallow-copy the individual stack frames within it. As a result, continuations appeared to have shallow semantics so long as the continuation stack had only a single frame. This change also removes an obsolete test from the brief period when we intended continuations to have deep-copy semantics, which has been passing basically by accident.
536 lines
18 KiB
C++
536 lines
18 KiB
C++
// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
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// Exceptions. See /LICENSE for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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#include "executable_semantics/interpreter/value.h"
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#include <algorithm>
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#include "common/check.h"
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#include "executable_semantics/common/arena.h"
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#include "executable_semantics/common/error.h"
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#include "executable_semantics/interpreter/frame.h"
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#include "llvm/ADT/StringExtras.h"
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#include "llvm/Support/Casting.h"
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namespace Carbon {
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using llvm::cast;
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auto FindInVarValues(const std::string& field, const VarValues& inits)
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-> std::optional<Nonnull<const Value*>> {
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for (auto& i : inits) {
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if (i.first == field) {
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return i.second;
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}
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}
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return std::nullopt;
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}
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auto FieldsEqual(const VarValues& ts1, const VarValues& ts2) -> bool {
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if (ts1.size() == ts2.size()) {
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for (auto& iter1 : ts1) {
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auto t2 = FindInVarValues(iter1.first, ts2);
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if (!t2) {
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return false;
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}
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if (!TypeEqual(iter1.second, *t2)) {
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return false;
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}
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}
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return true;
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} else {
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return false;
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}
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}
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auto StructValue::FindField(const std::string& name) const
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-> std::optional<Nonnull<const Value*>> {
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for (const TupleElement& element : elements_) {
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if (element.name == name) {
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return element.value;
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}
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}
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return std::nullopt;
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}
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auto TupleValue::FindField(const std::string& name) const
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-> std::optional<Nonnull<const Value*>> {
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for (const TupleElement& element : elements) {
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if (element.name == name) {
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return element.value;
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}
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}
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return std::nullopt;
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}
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namespace {
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auto GetMember(Nonnull<Arena*> arena, Nonnull<const Value*> v,
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const std::string& f, SourceLocation source_loc)
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-> Nonnull<const Value*> {
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switch (v->kind()) {
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case Value::Kind::StructValue: {
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std::optional<Nonnull<const Value*>> field =
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cast<StructValue>(*v).FindField(f);
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if (field == std::nullopt) {
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FATAL_RUNTIME_ERROR(source_loc) << "member " << f << " not in " << *v;
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}
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return *field;
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}
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case Value::Kind::NominalClassValue: {
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std::optional<Nonnull<const Value*>> field =
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cast<TupleValue>(*cast<NominalClassValue>(*v).Inits()).FindField(f);
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if (field == std::nullopt) {
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FATAL_RUNTIME_ERROR(source_loc) << "member " << f << " not in " << *v;
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}
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return *field;
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}
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case Value::Kind::TupleValue: {
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std::optional<Nonnull<const Value*>> field =
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cast<TupleValue>(*v).FindField(f);
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if (!field) {
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FATAL_RUNTIME_ERROR(source_loc) << "field " << f << " not in " << *v;
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}
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return *field;
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}
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case Value::Kind::ChoiceType: {
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const auto& choice = cast<ChoiceType>(*v);
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if (!FindInVarValues(f, choice.Alternatives())) {
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FATAL_RUNTIME_ERROR(source_loc)
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<< "alternative " << f << " not in " << *v;
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}
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return arena->New<AlternativeConstructorValue>(f, choice.Name());
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}
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default:
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FATAL() << "field access not allowed for value " << *v;
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}
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}
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} // namespace
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auto Value::GetField(Nonnull<Arena*> arena, const FieldPath& path,
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SourceLocation source_loc) const -> Nonnull<const Value*> {
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Nonnull<const Value*> value(this);
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for (const std::string& field : path.components) {
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value = GetMember(arena, value, field, source_loc);
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}
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return value;
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}
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namespace {
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auto SetFieldImpl(Nonnull<Arena*> arena, Nonnull<const Value*> value,
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std::vector<std::string>::const_iterator path_begin,
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std::vector<std::string>::const_iterator path_end,
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Nonnull<const Value*> field_value, SourceLocation source_loc)
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-> Nonnull<const Value*> {
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if (path_begin == path_end) {
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return field_value;
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}
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switch (value->kind()) {
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case Value::Kind::StructValue: {
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std::vector<TupleElement> elements = cast<StructValue>(*value).elements();
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auto it = std::find_if(elements.begin(), elements.end(),
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[path_begin](const TupleElement& element) {
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return element.name == *path_begin;
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});
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if (it == elements.end()) {
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FATAL_RUNTIME_ERROR(source_loc)
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<< "field " << *path_begin << " not in " << *value;
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}
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it->value = SetFieldImpl(arena, it->value, path_begin + 1, path_end,
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field_value, source_loc);
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return arena->New<StructValue>(elements);
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}
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case Value::Kind::NominalClassValue: {
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return SetFieldImpl(arena, cast<NominalClassValue>(*value).Inits(),
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path_begin, path_end, field_value, source_loc);
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}
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case Value::Kind::TupleValue: {
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std::vector<TupleElement> elements = cast<TupleValue>(*value).Elements();
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auto it = std::find_if(elements.begin(), elements.end(),
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[path_begin](const TupleElement& element) {
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return element.name == *path_begin;
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});
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if (it == elements.end()) {
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FATAL_RUNTIME_ERROR(source_loc)
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<< "field " << *path_begin << " not in " << *value;
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}
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it->value = SetFieldImpl(arena, it->value, path_begin + 1, path_end,
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field_value, source_loc);
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return arena->New<TupleValue>(elements);
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}
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default:
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FATAL() << "field access not allowed for value " << *value;
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}
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}
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} // namespace
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auto Value::SetField(Nonnull<Arena*> arena, const FieldPath& path,
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Nonnull<const Value*> field_value,
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SourceLocation source_loc) const -> Nonnull<const Value*> {
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return SetFieldImpl(arena, Nonnull<const Value*>(this),
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path.components.begin(), path.components.end(),
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field_value, source_loc);
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}
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void Value::Print(llvm::raw_ostream& out) const {
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switch (kind()) {
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case Value::Kind::AlternativeConstructorValue: {
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const auto& alt = cast<AlternativeConstructorValue>(*this);
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out << alt.ChoiceName() << "." << alt.AltName();
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break;
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}
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case Value::Kind::BindingPlaceholderValue: {
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const auto& placeholder = cast<BindingPlaceholderValue>(*this);
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if (placeholder.Name().has_value()) {
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out << *placeholder.Name();
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} else {
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out << "_";
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}
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out << ": " << *placeholder.Type();
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break;
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}
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case Value::Kind::AlternativeValue: {
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const auto& alt = cast<AlternativeValue>(*this);
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out << "alt " << alt.ChoiceName() << "." << alt.AltName() << " "
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<< *alt.Argument();
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break;
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}
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case Value::Kind::StructValue: {
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const auto& struct_val = cast<StructValue>(*this);
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out << "{";
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llvm::ListSeparator sep;
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for (const TupleElement& element : struct_val.elements()) {
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out << sep << "." << element.name << " = " << *element.value;
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}
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out << "}";
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break;
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}
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case Value::Kind::NominalClassValue: {
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const auto& s = cast<NominalClassValue>(*this);
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out << cast<NominalClassType>(*s.Type()).Name() << *s.Inits();
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break;
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}
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case Value::Kind::TupleValue: {
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out << "(";
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llvm::ListSeparator sep;
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for (const TupleElement& element : cast<TupleValue>(*this).Elements()) {
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out << sep << element.name << " = " << *element.value;
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}
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out << ")";
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break;
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}
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case Value::Kind::IntValue:
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out << cast<IntValue>(*this).Val();
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break;
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case Value::Kind::BoolValue:
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out << (cast<BoolValue>(*this).Val() ? "true" : "false");
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break;
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case Value::Kind::FunctionValue:
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out << "fun<" << cast<FunctionValue>(*this).Name() << ">";
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break;
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case Value::Kind::PointerValue:
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out << "ptr<" << cast<PointerValue>(*this).Val() << ">";
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break;
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case Value::Kind::BoolType:
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out << "Bool";
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break;
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case Value::Kind::IntType:
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out << "i32";
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break;
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case Value::Kind::TypeType:
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out << "Type";
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break;
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case Value::Kind::AutoType:
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out << "auto";
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break;
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case Value::Kind::ContinuationType:
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out << "Continuation";
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break;
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case Value::Kind::PointerType:
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out << *cast<PointerType>(*this).Type() << "*";
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break;
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case Value::Kind::FunctionType: {
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const auto& fn_type = cast<FunctionType>(*this);
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out << "fn ";
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if (fn_type.Deduced().size() > 0) {
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out << "[";
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unsigned int i = 0;
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for (const auto& deduced : fn_type.Deduced()) {
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if (i != 0) {
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out << ", ";
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}
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out << deduced.name << ":! " << *deduced.type;
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++i;
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}
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out << "]";
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}
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out << *fn_type.Param() << " -> " << *fn_type.Ret();
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break;
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}
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case Value::Kind::StructType: {
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out << "{";
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llvm::ListSeparator sep;
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for (const auto& [name, type] : cast<StructType>(*this).fields()) {
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out << sep << "." << name << ": " << *type;
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}
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out << "}";
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break;
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}
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case Value::Kind::NominalClassType:
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out << "class " << cast<NominalClassType>(*this).Name();
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break;
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case Value::Kind::ChoiceType:
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out << "choice " << cast<ChoiceType>(*this).Name();
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break;
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case Value::Kind::VariableType:
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out << cast<VariableType>(*this).Name();
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break;
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case Value::Kind::ContinuationValue: {
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out << "{";
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llvm::ListSeparator sep(" :: ");
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for (Nonnull<Frame*> frame : *cast<ContinuationValue>(*this).Stack()) {
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out << sep << *frame;
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}
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out << "}";
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break;
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}
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case Value::Kind::StringType:
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out << "String";
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break;
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case Value::Kind::StringValue:
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out << "\"";
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out.write_escaped(cast<StringValue>(*this).Val());
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out << "\"";
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break;
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}
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}
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auto CopyVal(Nonnull<Arena*> arena, Nonnull<const Value*> val,
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SourceLocation source_loc) -> Nonnull<const Value*> {
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switch (val->kind()) {
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case Value::Kind::TupleValue: {
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std::vector<TupleElement> elements;
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for (const TupleElement& element : cast<TupleValue>(*val).Elements()) {
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elements.push_back(
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{.name = element.name,
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.value = CopyVal(arena, element.value, source_loc)});
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}
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return arena->New<TupleValue>(std::move(elements));
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}
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case Value::Kind::AlternativeValue: {
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const auto& alt = cast<AlternativeValue>(*val);
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Nonnull<const Value*> arg = CopyVal(arena, alt.Argument(), source_loc);
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return arena->New<AlternativeValue>(alt.AltName(), alt.ChoiceName(), arg);
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}
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case Value::Kind::StructValue: {
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std::vector<TupleElement> elements;
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for (const TupleElement& element : cast<StructValue>(*val).elements()) {
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elements.push_back(
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{.name = element.name,
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.value = CopyVal(arena, element.value, source_loc)});
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}
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return arena->New<StructValue>(std::move(elements));
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}
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case Value::Kind::NominalClassValue: {
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const auto& s = cast<NominalClassValue>(*val);
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Nonnull<const Value*> inits = CopyVal(arena, s.Inits(), source_loc);
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return arena->New<NominalClassValue>(s.Type(), inits);
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}
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case Value::Kind::IntValue:
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return arena->New<IntValue>(cast<IntValue>(*val).Val());
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case Value::Kind::BoolValue:
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return arena->New<BoolValue>(cast<BoolValue>(*val).Val());
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case Value::Kind::FunctionValue: {
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const auto& fn_value = cast<FunctionValue>(*val);
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return arena->New<FunctionValue>(fn_value.Name(), fn_value.Param(),
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fn_value.Body());
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}
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case Value::Kind::PointerValue:
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return arena->New<PointerValue>(cast<PointerValue>(*val).Val());
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case Value::Kind::ContinuationValue:
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return arena->New<ContinuationValue>(
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cast<ContinuationValue>(*val).Stack());
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case Value::Kind::FunctionType: {
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const auto& fn_type = cast<FunctionType>(*val);
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return arena->New<FunctionType>(
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fn_type.Deduced(), CopyVal(arena, fn_type.Param(), source_loc),
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CopyVal(arena, fn_type.Ret(), source_loc));
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}
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case Value::Kind::PointerType:
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return arena->New<PointerType>(
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CopyVal(arena, cast<PointerType>(*val).Type(), source_loc));
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case Value::Kind::IntType:
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return arena->New<IntType>();
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case Value::Kind::BoolType:
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return arena->New<BoolType>();
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case Value::Kind::TypeType:
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return arena->New<TypeType>();
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case Value::Kind::AutoType:
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return arena->New<AutoType>();
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case Value::Kind::ContinuationType:
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return arena->New<ContinuationType>();
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case Value::Kind::StringType:
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return arena->New<StringType>();
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case Value::Kind::StringValue:
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return arena->New<StringValue>(cast<StringValue>(*val).Val());
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case Value::Kind::StructType: {
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VarValues fields;
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for (const auto& [name, type] : cast<StructType>(*val).fields()) {
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fields.push_back({name, CopyVal(arena, type, source_loc)});
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}
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return arena->New<StructType>(fields);
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}
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case Value::Kind::VariableType:
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case Value::Kind::NominalClassType:
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case Value::Kind::ChoiceType:
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case Value::Kind::BindingPlaceholderValue:
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case Value::Kind::AlternativeConstructorValue:
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// TODO: These should be copied so that they don't get destructed.
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return val;
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}
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}
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auto TypeEqual(Nonnull<const Value*> t1, Nonnull<const Value*> t2) -> bool {
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if (t1->kind() != t2->kind()) {
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return false;
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}
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switch (t1->kind()) {
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case Value::Kind::PointerType:
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return TypeEqual(cast<PointerType>(*t1).Type(),
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cast<PointerType>(*t2).Type());
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case Value::Kind::FunctionType: {
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const auto& fn1 = cast<FunctionType>(*t1);
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const auto& fn2 = cast<FunctionType>(*t2);
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return TypeEqual(fn1.Param(), fn2.Param()) &&
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TypeEqual(fn1.Ret(), fn2.Ret());
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}
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case Value::Kind::StructType: {
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const auto& struct1 = cast<StructType>(*t1);
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const auto& struct2 = cast<StructType>(*t2);
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if (struct1.fields().size() != struct2.fields().size()) {
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return false;
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}
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for (size_t i = 0; i < struct1.fields().size(); ++i) {
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if (struct1.fields()[i].first != struct2.fields()[i].first ||
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!TypeEqual(struct1.fields()[i].second,
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struct2.fields()[i].second)) {
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return false;
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}
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}
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return true;
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}
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case Value::Kind::NominalClassType:
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return cast<NominalClassType>(*t1).Name() ==
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cast<NominalClassType>(*t2).Name();
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case Value::Kind::ChoiceType:
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return cast<ChoiceType>(*t1).Name() == cast<ChoiceType>(*t2).Name();
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case Value::Kind::TupleValue: {
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const auto& tup1 = cast<TupleValue>(*t1);
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const auto& tup2 = cast<TupleValue>(*t2);
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if (tup1.Elements().size() != tup2.Elements().size()) {
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return false;
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}
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for (size_t i = 0; i < tup1.Elements().size(); ++i) {
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if (tup1.Elements()[i].name != tup2.Elements()[i].name ||
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!TypeEqual(tup1.Elements()[i].value, tup2.Elements()[i].value)) {
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return false;
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}
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}
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return true;
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}
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case Value::Kind::IntType:
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case Value::Kind::BoolType:
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case Value::Kind::ContinuationType:
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case Value::Kind::TypeType:
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case Value::Kind::StringType:
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return true;
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case Value::Kind::VariableType:
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return cast<VariableType>(*t1).Name() == cast<VariableType>(*t2).Name();
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default:
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FATAL() << "TypeEqual used to compare non-type values\n"
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<< *t1 << "\n"
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<< *t2;
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}
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}
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// Returns true if all the fields of the two tuples contain equal values
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// and returns false otherwise.
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static auto FieldsValueEqual(const std::vector<TupleElement>& ts1,
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const std::vector<TupleElement>& ts2,
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SourceLocation source_loc) -> bool {
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if (ts1.size() != ts2.size()) {
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return false;
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}
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for (const TupleElement& element : ts1) {
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auto iter = std::find_if(
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ts2.begin(), ts2.end(),
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[&](const TupleElement& e2) { return e2.name == element.name; });
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if (iter == ts2.end()) {
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return false;
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}
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if (!ValueEqual(element.value, iter->value, source_loc)) {
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return false;
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}
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}
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return true;
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}
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// Returns true if the two values are equal and returns false otherwise.
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//
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// This function implements the `==` operator of Carbon.
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auto ValueEqual(Nonnull<const Value*> v1, Nonnull<const Value*> v2,
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SourceLocation source_loc) -> bool {
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|
if (v1->kind() != v2->kind()) {
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|
return false;
|
|
}
|
|
switch (v1->kind()) {
|
|
case Value::Kind::IntValue:
|
|
return cast<IntValue>(*v1).Val() == cast<IntValue>(*v2).Val();
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|
case Value::Kind::BoolValue:
|
|
return cast<BoolValue>(*v1).Val() == cast<BoolValue>(*v2).Val();
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|
case Value::Kind::PointerValue:
|
|
return cast<PointerValue>(*v1).Val() == cast<PointerValue>(*v2).Val();
|
|
case Value::Kind::FunctionValue: {
|
|
std::optional<Nonnull<const Statement*>> body1 =
|
|
cast<FunctionValue>(*v1).Body();
|
|
std::optional<Nonnull<const Statement*>> body2 =
|
|
cast<FunctionValue>(*v2).Body();
|
|
return body1.has_value() == body2.has_value() &&
|
|
(!body1.has_value() || *body1 == *body2);
|
|
}
|
|
case Value::Kind::TupleValue:
|
|
return FieldsValueEqual(cast<TupleValue>(*v1).Elements(),
|
|
cast<TupleValue>(*v2).Elements(), source_loc);
|
|
case Value::Kind::StructValue:
|
|
return FieldsValueEqual(cast<StructValue>(*v1).elements(),
|
|
cast<StructValue>(*v2).elements(), source_loc);
|
|
case Value::Kind::StringValue:
|
|
return cast<StringValue>(*v1).Val() == cast<StringValue>(*v2).Val();
|
|
case Value::Kind::IntType:
|
|
case Value::Kind::BoolType:
|
|
case Value::Kind::TypeType:
|
|
case Value::Kind::FunctionType:
|
|
case Value::Kind::PointerType:
|
|
case Value::Kind::AutoType:
|
|
case Value::Kind::StructType:
|
|
case Value::Kind::NominalClassType:
|
|
case Value::Kind::ChoiceType:
|
|
case Value::Kind::ContinuationType:
|
|
case Value::Kind::VariableType:
|
|
case Value::Kind::StringType:
|
|
return TypeEqual(v1, v2);
|
|
case Value::Kind::NominalClassValue:
|
|
case Value::Kind::AlternativeValue:
|
|
case Value::Kind::BindingPlaceholderValue:
|
|
case Value::Kind::AlternativeConstructorValue:
|
|
case Value::Kind::ContinuationValue:
|
|
FATAL() << "ValueEqual does not support this kind of value: " << *v1;
|
|
}
|
|
}
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|
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} // namespace Carbon
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