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https://github.com/carbon-language/carbon-lang.git
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Separate alive flag from the Value class (#408)
* separate the alive flag from the Value class * restored KillValue, added KillAddress * added comments * Update executable_semantics/interpreter/interpreter.cpp Co-authored-by: Dave Abrahams <dabrahams@google.com> * Update executable_semantics/interpreter/interpreter.cpp Co-authored-by: Dave Abrahams <dabrahams@google.com> * Update executable_semantics/interpreter/interpreter.cpp Co-authored-by: Dave Abrahams <dabrahams@google.com> * finish edits from Dave Co-authored-by: Dave Abrahams <dabrahams@google.com>
This commit is contained in:
Jeremy G. Siek
committed by
GitHub
GitHub
co-authored by
Dave Abrahams
Dave Abrahams
parent
b8f6602857
commit
1da97fc9cf
@@ -49,23 +49,27 @@ auto AllocateValue(Value* v) -> Address {
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// or to leave it up to the caller.
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Address a = state->heap.size();
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state->heap.push_back(v);
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state->alive.push_back(true);
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return a;
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}
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auto CopyVal(Value* val, int line_num) -> Value* {
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CheckAlive(val, line_num);
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switch (val->tag) {
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case ValKind::TupleV: {
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auto elts = new std::vector<std::pair<std::string, Address>>();
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for (auto& i : *val->u.tuple.elts) {
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CheckAlive(i.second, line_num);
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Value* elt = CopyVal(state->heap[i.second], line_num);
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elts->push_back(make_pair(i.first, AllocateValue(elt)));
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Address new_address = AllocateValue(elt);
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elts->push_back(make_pair(i.first, new_address));
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}
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return MakeTupleVal(elts);
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}
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case ValKind::AltV: {
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Value* arg = CopyVal(val->u.alt.arg, line_num);
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return MakeAltVal(*val->u.alt.alt_name, *val->u.alt.choice_name, arg);
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Value* arg = CopyVal(state->heap[val->u.alt.argument], line_num);
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Address argument_address = AllocateValue(arg);
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return MakeAltVal(*val->u.alt.alt_name, *val->u.alt.choice_name,
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argument_address);
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}
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case ValKind::StructV: {
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Value* inits = CopyVal(val->u.struct_val.inits, line_num);
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@@ -112,24 +116,20 @@ auto CopyVal(Value* val, int line_num) -> Value* {
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}
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}
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void KillValue(Value* val) {
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val->alive = false;
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void KillObject(Address address);
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// Marks all of the sub-objects of this value as dead.
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void KillSubObjects(Value* val) {
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switch (val->tag) {
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case ValKind::AltV:
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KillValue(val->u.alt.arg);
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KillObject(val->u.alt.argument);
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break;
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case ValKind::StructV:
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KillValue(val->u.struct_val.inits);
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KillSubObjects(val->u.struct_val.inits);
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break;
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case ValKind::TupleV:
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for (auto& elt : *val->u.tuple.elts) {
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if (state->heap[elt.second]->alive) {
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KillValue(state->heap[elt.second]);
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} else {
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std::cerr << "runtime error, killing an already dead value"
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<< std::endl;
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exit(-1);
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}
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KillObject(elt.second);
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}
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break;
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default:
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@@ -137,6 +137,17 @@ void KillValue(Value* val) {
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}
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}
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// Marks the object at this address, and all of its sub-objects, as dead.
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void KillObject(Address address) {
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if (state->alive[address]) {
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state->alive[address] = false;
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KillSubObjects(state->heap[address]);
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} else {
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std::cerr << "runtime error, killing an already dead value" << std::endl;
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exit(-1);
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}
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}
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void PrintEnv(Env env, std::ostream& out) {
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for (const auto& [name, value] : env) {
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out << name << ": ";
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@@ -198,7 +209,6 @@ void PrintState(std::ostream& out) {
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//
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auto ValToInt(Value* v, int line_num) -> int {
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CheckAlive(v, line_num);
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switch (v->tag) {
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case ValKind::IntV:
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return v->u.integer;
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@@ -210,7 +220,6 @@ auto ValToInt(Value* v, int line_num) -> int {
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}
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auto ValToBool(Value* v, int line_num) -> int {
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CheckAlive(v, line_num);
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switch (v->tag) {
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case ValKind::BoolV:
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return v->u.boolean;
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@@ -221,7 +230,7 @@ auto ValToBool(Value* v, int line_num) -> int {
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}
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auto ValToPtr(Value* v, int line_num) -> Address {
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CheckAlive(v, line_num);
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CheckAlive(v->u.ptr, line_num);
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switch (v->tag) {
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case ValKind::PtrV:
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return v->u.ptr;
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@@ -317,7 +326,6 @@ auto VariableDeclaration::InitGlobals(Env& globals) const -> void {
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// E is the environment (functions + parameters + locals)
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// F is the function
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void CallFunction(int line_num, std::vector<Value*> operas, State* state) {
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CheckAlive(operas[0], line_num);
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switch (operas[0]->tag) {
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case ValKind::FunV: {
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// Bind arguments to parameters
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@@ -345,8 +353,9 @@ void CallFunction(int line_num, std::vector<Value*> operas, State* state) {
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}
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case ValKind::AltConsV: {
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Value* arg = CopyVal(operas[1], line_num);
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Value* av = MakeAltVal(*operas[0]->u.alt_cons.alt_name,
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*operas[0]->u.alt_cons.choice_name, arg);
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Value* av =
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MakeAltVal(*operas[0]->u.alt_cons.alt_name,
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*operas[0]->u.alt_cons.choice_name, AllocateValue(arg));
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Frame* frame = state->stack.Top();
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frame->todo.Push(MakeValAct(av));
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break;
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@@ -366,7 +375,7 @@ void KillScope(int line_num, Scope* scope) {
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std::cerr << "internal error in KillScope" << std::endl;
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exit(-1);
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}
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KillValue(state->heap[*a]);
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KillObject(*a);
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}
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}
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@@ -444,7 +453,8 @@ auto PatternMatch(Value* p, Value* v, Env env, std::list<std::string>* vars,
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return std::nullopt;
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}
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std::optional<Env> env_with_matches =
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PatternMatch(p->u.alt.arg, v->u.alt.arg, env, vars, line_num);
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PatternMatch(state->heap[p->u.alt.argument],
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state->heap[v->u.alt.argument], env, vars, line_num);
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if (!env_with_matches) {
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return std::nullopt;
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}
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@@ -525,7 +535,8 @@ void PatternAssignment(Value* pat, Value* val, int line_num) {
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std::cerr << "internal error in pattern assignment" << std::endl;
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exit(-1);
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}
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PatternAssignment(pat->u.alt.arg, val->u.alt.arg, line_num);
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PatternAssignment(state->heap[pat->u.alt.argument],
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state->heap[val->u.alt.argument], line_num);
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break;
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}
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default:
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@@ -569,7 +580,7 @@ void StepLvalue() {
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exit(-1);
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}
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Value* v = MakePtrVal(*pointer);
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CheckAlive(v, exp->line_num);
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CheckAlive(*pointer, exp->line_num);
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frame->todo.Pop();
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frame->todo.Push(MakeValAct(v));
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break;
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@@ -950,7 +961,7 @@ void HandleValue() {
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}
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switch (act->tag) {
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case ActionKind::DeleteTmpAction: {
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KillValue(state->heap[act->u.delete_tmp]);
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KillObject(act->u.delete_tmp);
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frame->todo.Pop(2);
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frame->todo.Push(val_act);
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break;
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