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https://github.com/dart-lang/sdk
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Rename FlowModel.removePromotedAll to .conservativeJoin.
This makes the implementation consistent with the spec text in
1ed6bab4cc.
Change-Id: Ie25b928c5aacb45a18e85c6f9196b5b55f083478
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/152983
Reviewed-by: Konstantin Shcheglov <scheglov@google.com>
Commit-Queue: Paul Berry <paulberry@google.com>
This commit is contained in:
Paul Berry
commit-bot@chromium.org
parent
6d3928554c
commit
63feed82e1
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@ -1188,6 +1188,63 @@ class FlowModel<Variable, Type> {
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}());
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}
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/// Updates the state to indicate that the given [writtenVariables] are no
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/// longer promoted and are no longer definitely unassigned, and the given
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/// [capturedVariables] have been captured by closures.
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///
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/// This is used at the top of loops to conservatively cancel the promotion of
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/// variables that are modified within the loop, so that we correctly analyze
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/// code like the following:
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///
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/// if (x is int) {
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/// x.isEven; // OK, promoted to int
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/// while (true) {
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/// x.isEven; // ERROR: promotion lost
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/// x = 'foo';
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/// }
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/// }
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///
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/// Note that a more accurate analysis would be to iterate to a fixed point,
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/// and only remove promotions if it can be shown that they aren't restored
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/// later in the loop body. If we switch to a fixed point analysis, we should
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/// be able to remove this method.
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FlowModel<Variable, Type> conservativeJoin(
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Iterable<Variable> writtenVariables,
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Iterable<Variable> capturedVariables) {
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Map<Variable, VariableModel<Variable, Type>> newVariableInfo;
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for (Variable variable in writtenVariables) {
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VariableModel<Variable, Type> info = infoFor(variable);
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VariableModel<Variable, Type> newInfo =
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info.discardPromotionsAndMarkNotUnassigned();
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if (!identical(info, newInfo)) {
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(newVariableInfo ??=
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new Map<Variable, VariableModel<Variable, Type>>.from(
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variableInfo))[variable] = newInfo;
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}
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}
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for (Variable variable in capturedVariables) {
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VariableModel<Variable, Type> info = variableInfo[variable];
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if (info == null) {
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(newVariableInfo ??=
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new Map<Variable, VariableModel<Variable, Type>>.from(
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variableInfo))[variable] = new VariableModel<Variable, Type>(
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null, const [], false, false, true);
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} else if (!info.writeCaptured) {
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(newVariableInfo ??=
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new Map<Variable, VariableModel<Variable, Type>>.from(
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variableInfo))[variable] = info.writeCapture();
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}
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}
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FlowModel<Variable, Type> result = newVariableInfo == null
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? this
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: new FlowModel<Variable, Type>._(reachable, newVariableInfo);
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return result;
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}
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/// Register a declaration of the [variable].
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/// Should also be called for function parameters.
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///
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@ -1236,62 +1293,6 @@ class FlowModel<Variable, Type> {
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return new FlowModel<Variable, Type>._(reachable, newVariableInfo);
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}
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/// Updates the state to indicate that the given [writtenVariables] are no
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/// longer promoted; they are presumed to have their declared types.
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///
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/// This is used at the top of loops to conservatively cancel the promotion of
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/// variables that are modified within the loop, so that we correctly analyze
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/// code like the following:
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///
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/// if (x is int) {
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/// x.isEven; // OK, promoted to int
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/// while (true) {
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/// x.isEven; // ERROR: promotion lost
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/// x = 'foo';
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/// }
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/// }
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///
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/// Note that a more accurate analysis would be to iterate to a fixed point,
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/// and only remove promotions if it can be shown that they aren't restored
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/// later in the loop body. If we switch to a fixed point analysis, we should
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/// be able to remove this method.
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FlowModel<Variable, Type> removePromotedAll(
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Iterable<Variable> writtenVariables,
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Iterable<Variable> capturedVariables) {
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Map<Variable, VariableModel<Variable, Type>> newVariableInfo;
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for (Variable variable in writtenVariables) {
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VariableModel<Variable, Type> info = infoFor(variable);
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VariableModel<Variable, Type> newInfo =
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info.discardPromotionsAndMarkNotUnassigned();
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if (!identical(info, newInfo)) {
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(newVariableInfo ??=
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new Map<Variable, VariableModel<Variable, Type>>.from(
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variableInfo))[variable] = newInfo;
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}
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}
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for (Variable variable in capturedVariables) {
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VariableModel<Variable, Type> info = variableInfo[variable];
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if (info == null) {
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(newVariableInfo ??=
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new Map<Variable, VariableModel<Variable, Type>>.from(
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variableInfo))[variable] = new VariableModel<Variable, Type>(
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null, const [], false, false, true);
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} else if (!info.writeCaptured) {
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(newVariableInfo ??=
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new Map<Variable, VariableModel<Variable, Type>>.from(
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variableInfo))[variable] = info.writeCapture();
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}
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}
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FlowModel<Variable, Type> result = newVariableInfo == null
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? this
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: new FlowModel<Variable, Type>._(reachable, newVariableInfo);
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return result;
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}
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/// Updates the state to reflect a control path that is known to have
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/// previously passed through some [other] state.
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///
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@ -2383,7 +2384,7 @@ class _FlowAnalysisImpl<Node, Statement extends Node, Expression, Variable,
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_BranchTargetContext<Variable, Type> context =
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new _BranchTargetContext<Variable, Type>();
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_stack.add(context);
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_current = _current.removePromotedAll(info._written, info._captured);
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_current = _current.conservativeJoin(info._written, info._captured);
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_statementToContext[doStatement] = context;
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}
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@ -2453,7 +2454,7 @@ class _FlowAnalysisImpl<Node, Statement extends Node, Expression, Variable,
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void for_conditionBegin(Node node) {
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AssignedVariablesNodeInfo<Variable> info =
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_assignedVariables._getInfoForNode(node);
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_current = _current.removePromotedAll(info._written, info._captured);
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_current = _current.conservativeJoin(info._written, info._captured);
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}
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@override
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@ -2481,7 +2482,7 @@ class _FlowAnalysisImpl<Node, Statement extends Node, Expression, Variable,
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_SimpleStatementContext<Variable, Type> context =
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new _SimpleStatementContext<Variable, Type>(_current);
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_stack.add(context);
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_current = _current.removePromotedAll(info._written, info._captured);
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_current = _current.conservativeJoin(info._written, info._captured);
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if (loopVariable != null) {
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_current = _current.write(loopVariable, writtenType, typeOperations);
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}
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@ -2499,9 +2500,9 @@ class _FlowAnalysisImpl<Node, Statement extends Node, Expression, Variable,
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AssignedVariablesNodeInfo<Variable> info =
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_assignedVariables._getInfoForNode(node);
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++_functionNestingLevel;
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_current = _current.removePromotedAll(const [], info._written);
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_current = _current.conservativeJoin(const [], info._written);
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_stack.add(new _SimpleContext(_current));
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_current = _current.removePromotedAll(_assignedVariables._anywhere._written,
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_current = _current.conservativeJoin(_assignedVariables._anywhere._written,
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_assignedVariables._anywhere._captured);
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}
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@ -2726,7 +2727,7 @@ class _FlowAnalysisImpl<Node, Statement extends Node, Expression, Variable,
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_stack.last as _SimpleStatementContext<Variable, Type>;
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if (hasLabel) {
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_current =
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context._previous.removePromotedAll(info._written, info._captured);
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context._previous.conservativeJoin(info._written, info._captured);
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} else {
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_current = context._previous;
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}
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@ -2772,7 +2773,7 @@ class _FlowAnalysisImpl<Node, Statement extends Node, Expression, Variable,
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AssignedVariablesNodeInfo<Variable> info =
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_assignedVariables._getInfoForNode(body);
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FlowModel<Variable, Type> beforeCatch =
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beforeBody.removePromotedAll(info._written, info._captured);
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beforeBody.conservativeJoin(info._written, info._captured);
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context._beforeCatch = beforeCatch;
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context._afterBodyAndCatches = afterBody;
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@ -2830,7 +2831,7 @@ class _FlowAnalysisImpl<Node, Statement extends Node, Expression, Variable,
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_stack.last as _TryContext<Variable, Type>;
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context._afterBodyAndCatches = _current;
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_current = _join(_current,
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context._previous.removePromotedAll(info._written, info._captured));
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context._previous.conservativeJoin(info._written, info._captured));
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}
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@override
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@ -2854,7 +2855,7 @@ class _FlowAnalysisImpl<Node, Statement extends Node, Expression, Variable,
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void whileStatement_conditionBegin(Node node) {
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AssignedVariablesNodeInfo<Variable> info =
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_assignedVariables._getInfoForNode(node);
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_current = _current.removePromotedAll(info._written, info._captured);
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_current = _current.conservativeJoin(info._written, info._captured);
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}
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@override
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@ -2000,7 +2000,7 @@ main() {
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x: _matchVariableModel(chain: null),
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});
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var s2 = s1.removePromotedAll([], [x]);
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var s2 = s1.conservativeJoin([], [x]);
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expect(s2.variableInfo, {
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x: _matchVariableModel(chain: null, writeCaptured: true),
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});
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@ -2432,14 +2432,14 @@ main() {
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});
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});
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group('removePromotedAll', () {
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group('conservativeJoin', () {
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test('unchanged', () {
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var h = _Harness();
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var s1 = FlowModel<_Var, _Type>(true)
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.declare(intQVar, true)
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.tryPromoteForTypeCheck(h, objectQVar, _Type('int'))
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.ifTrue;
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var s2 = s1.removePromotedAll([intQVar], []);
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var s2 = s1.conservativeJoin([intQVar], []);
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expect(s2, same(s1));
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});
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@ -2450,7 +2450,7 @@ main() {
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.ifTrue
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.tryPromoteForTypeCheck(h, intQVar, _Type('int'))
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.ifTrue;
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var s2 = s1.removePromotedAll([intQVar], []);
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var s2 = s1.conservativeJoin([intQVar], []);
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expect(s2.reachable, true);
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expect(s2.variableInfo, {
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objectQVar: _matchVariableModel(chain: ['int'], ofInterest: ['int']),
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@ -2465,7 +2465,7 @@ main() {
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.ifTrue
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.tryPromoteForTypeCheck(h, intQVar, _Type('int'))
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.ifTrue;
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var s2 = s1.removePromotedAll([], [intQVar]);
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var s2 = s1.conservativeJoin([], [intQVar]);
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expect(s2.reachable, true);
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expect(s2.variableInfo, {
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objectQVar: _matchVariableModel(chain: ['int'], ofInterest: ['int']),
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@ -2518,8 +2518,8 @@ main() {
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.declare(c, false)
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.declare(d, false);
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// In s1, a and b are write captured. In s2, a and c are.
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var s1 = s0.removePromotedAll([a, b], [a, b]);
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var s2 = s1.removePromotedAll([a, c], [a, c]);
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var s1 = s0.conservativeJoin([a, b], [a, b]);
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var s2 = s1.conservativeJoin([a, c], [a, c]);
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var result = s2.restrict(h, s1, Set());
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expect(
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result.infoFor(a),
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