[dart2wasm] Bypass list indexing checks inside type checks
Apart from improving the performance of type checks, this avoids type
checks inside type checks, which could lead to infinite recursion.
The recursion problem was hidden by the type check specialization for
simple interface type checks and exposed by `--verify-type-checks`.
Change-Id: Icbaebd6d68e6576a784fe3efaee81d4479adba5a
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/336422
Reviewed-by: Ömer Ağacan <omersa@google.com>
diff --git a/sdk/lib/_internal/wasm/lib/type.dart b/sdk/lib/_internal/wasm/lib/type.dart
index e24e4f3..41bde92 100644
--- a/sdk/lib/_internal/wasm/lib/type.dart
+++ b/sdk/lib/_internal/wasm/lib/type.dart
@@ -28,6 +28,15 @@
bool get isNotEmpty => length != 0;
}
+// Direct getter to bypass the covariance check and the bounds check when
+// indexing into a Dart list. This makes the indexing more efficient and avoids
+// performing type checks while performing type checks.
+extension _BypassListIndexingChecks<T> on List<T> {
+ @pragma("wasm:prefer-inline")
+ T _getUnchecked(int index) =>
+ unsafeCast(unsafeCast<_ListBase<T>>(this)._data.read(index));
+}
+
// TODO(joshualitt): Once we have RTI fully working, we'd like to explore
// implementing [isSubtype] using inheritance.
// TODO(joshualitt): We can cache the result of [_FutureOrType.asFuture].
@@ -361,15 +370,22 @@
if (requiredParameterCount != other.requiredParameterCount) return false;
if (namedParameters.length != other.namedParameters.length) return false;
for (int i = 0; i < typeParameterBounds.length; i++) {
- if (typeParameterBounds[i] != other.typeParameterBounds[i]) return false;
+ if (typeParameterBounds._getUnchecked(i) !=
+ other.typeParameterBounds._getUnchecked(i)) {
+ return false;
+ }
}
for (int i = 0; i < positionalParameters.length; i++) {
- if (positionalParameters[i] != other.positionalParameters[i]) {
+ if (positionalParameters._getUnchecked(i) !=
+ other.positionalParameters._getUnchecked(i)) {
return false;
}
}
for (int i = 0; i < namedParameters.length; i++) {
- if (namedParameters[i] != other.namedParameters[i]) return false;
+ if (namedParameters._getUnchecked(i) !=
+ other.namedParameters._getUnchecked(i)) {
+ return false;
+ }
}
return true;
}
@@ -378,16 +394,16 @@
int get hashCode {
int hash = mix64(ClassID.cidFunctionType);
for (int i = 0; i < typeParameterBounds.length; i++) {
- hash = mix64(hash ^ typeParameterBounds[i].hashCode);
+ hash = mix64(hash ^ typeParameterBounds._getUnchecked(i).hashCode);
}
hash = mix64(hash ^ (isDeclaredNullable ? 1 : 0));
hash = mix64(hash ^ returnType.hashCode);
for (int i = 0; i < positionalParameters.length; i++) {
- hash = mix64(hash ^ positionalParameters[i].hashCode);
+ hash = mix64(hash ^ positionalParameters._getUnchecked(i).hashCode);
}
hash = mix64(hash ^ requiredParameterCount);
for (int i = 0; i < namedParameters.length; i++) {
- hash = mix64(hash ^ namedParameters[i].hashCode);
+ hash = mix64(hash ^ namedParameters._getUnchecked(i).hashCode);
}
return hash;
}
@@ -400,7 +416,7 @@
for (int i = 0; i < typeParameterBounds.length; i++) {
if (i > 0) s.write(", ");
s.write("X${typeParameterOffset + i}");
- final bound = typeParameterBounds[i];
+ final bound = typeParameterBounds._getUnchecked(i);
if (!(bound.isTop && bound.isDeclaredNullable)) {
s.write(" extends ");
s.write(bound);
@@ -412,7 +428,7 @@
for (int i = 0; i < positionalParameters.length; i++) {
if (i > 0) s.write(", ");
if (i == requiredParameterCount) s.write("[");
- s.write(positionalParameters[i]);
+ s.write(positionalParameters._getUnchecked(i));
}
if (requiredParameterCount < positionalParameters.length) s.write("]");
if (namedParameters.isNotEmpty) {
@@ -420,7 +436,7 @@
s.write("{");
for (int i = 0; i < namedParameters.length; i++) {
if (i > 0) s.write(", ");
- s.write(namedParameters[i]);
+ s.write(namedParameters._getUnchecked(i));
}
s.write("}");
}
@@ -465,7 +481,7 @@
final int numNames = names.length;
for (int i = 0; i < numPositionals; i += 1) {
- buffer.write(fieldTypes[i]);
+ buffer.write(fieldTypes._getUnchecked(i));
if (i != fieldTypes.length - 1) {
buffer.write(', ');
}
@@ -474,8 +490,8 @@
if (names.isNotEmpty) {
buffer.write('{');
for (int i = 0; i < numNames; i += 1) {
- final String fieldName = names[i];
- final _Type fieldType = fieldTypes[numPositionals + i];
+ final String fieldName = names._getUnchecked(i);
+ final _Type fieldType = fieldTypes._getUnchecked(numPositionals + i);
buffer.write(fieldType);
buffer.write(' ');
buffer.write(fieldName);
@@ -503,7 +519,8 @@
}
for (int fieldIdx = 0; fieldIdx < fieldTypes.length; fieldIdx += 1) {
- if (fieldTypes[fieldIdx] != other.fieldTypes[fieldIdx]) {
+ if (fieldTypes._getUnchecked(fieldIdx) !=
+ other.fieldTypes._getUnchecked(fieldIdx)) {
return false;
}
}
@@ -562,7 +579,8 @@
/// Look up the bound of a type parameter in its adjusted environment.
_Type lookupAdjusted(_FunctionTypeParameterType param) {
- return type.typeParameterBounds[param.index - type.typeParameterOffset];
+ return type.typeParameterBounds
+ ._getUnchecked(param.index - type.typeParameterOffset);
}
}
@@ -587,7 +605,8 @@
// [type] as nullable.
// Note: This will throw if the required nullability is impossible to
// generate.
- _Type substitution = substitutions[typeParameter.environmentIndex];
+ _Type substitution =
+ substitutions._getUnchecked(typeParameter.environmentIndex);
if (typeParameter.isDeclaredNullable) return substitution.asNullable;
return substitution;
}
@@ -598,8 +617,8 @@
_FunctionType? rootFunction) {
if (rootFunction != null &&
typeParameter.index >= rootFunction.typeParameterOffset) {
- _Type substitution =
- substitutions[typeParameter.index - rootFunction.typeParameterOffset];
+ _Type substitution = substitutions._getUnchecked(
+ typeParameter.index - rootFunction.typeParameterOffset);
if (typeParameter.isDeclaredNullable) return substitution.asNullable;
return substitution;
} else {
@@ -741,15 +760,22 @@
// Otherwise, check if [s] is a subtype of [t], and if it is then compare
// [s]'s type substitutions with [t]'s type arguments.
- List<int> sSupers = typeRulesSupers[sId];
+ List<int> sSupers = typeRulesSupers._getUnchecked(sId);
if (sSupers.isEmpty) return false;
- int sSuperIndexOfT = sSupers.indexOf(tId);
+ int sSuperIndexOfT = -1;
+ for (int i = 0; i < sSupers.length; i++) {
+ if (sSupers._getUnchecked(i) == tId) {
+ sSuperIndexOfT = i;
+ break;
+ }
+ }
if (sSuperIndexOfT == -1) return false;
- assert(sSuperIndexOfT < typeRulesSubstitutions[sId].length);
+ assert(sSuperIndexOfT < typeRulesSubstitutions._getUnchecked(sId).length);
// Return early if we don't have to check type arguments.
WasmObjectArray<_Type> sTypeArguments = s.typeArguments;
- List<_Type> substitutions = typeRulesSubstitutions[sId][sSuperIndexOfT];
+ List<_Type> substitutions =
+ typeRulesSubstitutions._getUnchecked(sId)._getUnchecked(sSuperIndexOfT);
if (substitutions.isEmpty && sTypeArguments.isEmpty) {
return true;
}
@@ -771,7 +797,7 @@
WasmObjectArray<_Type>(substitutions.length, _literal<dynamic>());
for (int i = 0; i < substitutions.length; i++) {
substituted[i] = substituteTypeArgument(
- substitutions[i], typeArgumentsForSubstitution, null);
+ substitutions._getUnchecked(i), typeArgumentsForSubstitution, null);
}
return areTypeArgumentsSubtypes(substituted, sEnv, t.typeArguments, tEnv);
}
@@ -788,8 +814,8 @@
int tTypeParameterCount = t.typeParameterBounds.length;
if (sTypeParameterCount != tTypeParameterCount) return false;
for (int i = 0; i < sTypeParameterCount; i++) {
- if (!areEquivalent(
- s.typeParameterBounds[i], sEnv, t.typeParameterBounds[i], tEnv)) {
+ if (!areEquivalent(s.typeParameterBounds._getUnchecked(i), sEnv,
+ t.typeParameterBounds._getUnchecked(i), tEnv)) {
return false;
}
}
@@ -816,8 +842,8 @@
// Check all [t] positional arguments are subtypes of [s] positional
// arguments.
for (int i = 0; i < tPositionalLength; i++) {
- _Type sParameter = sPositional[i];
- _Type tParameter = tPositional[i];
+ _Type sParameter = sPositional._getUnchecked(i);
+ _Type tParameter = tPositional._getUnchecked(i);
if (!isSubtype(tParameter, tEnv, sParameter, sEnv)) {
return false;
}
@@ -831,11 +857,11 @@
int tNamedLength = tNamed.length;
int sIndex = 0;
for (int tIndex = 0; tIndex < tNamedLength; tIndex++) {
- _NamedParameter tNamedParameter = tNamed[tIndex];
+ _NamedParameter tNamedParameter = tNamed._getUnchecked(tIndex);
String tName = tNamedParameter.name;
while (true) {
if (sIndex >= sNamedLength) return false;
- _NamedParameter sNamedParameter = sNamed[sIndex];
+ _NamedParameter sNamedParameter = sNamed._getUnchecked(sIndex);
String sName = sNamedParameter.name;
sIndex++;
int sNameComparedToTName = sName.compareTo(tName);
@@ -855,7 +881,7 @@
}
}
while (sIndex < sNamedLength) {
- if (sNamed[sIndex].isRequired) return false;
+ if (sNamed._getUnchecked(sIndex).isRequired) return false;
sIndex++;
}
return true;
@@ -871,8 +897,8 @@
final int numFields = s.fieldTypes.length;
for (int fieldIdx = 0; fieldIdx < numFields; fieldIdx += 1) {
- if (!isSubtype(
- s.fieldTypes[fieldIdx], sEnv, t.fieldTypes[fieldIdx], tEnv)) {
+ if (!isSubtype(s.fieldTypes._getUnchecked(fieldIdx), sEnv,
+ t.fieldTypes._getUnchecked(fieldIdx), tEnv)) {
return false;
}
}
@@ -1063,7 +1089,8 @@
int namedParamIdx = 0;
int namedArgIdx = 0;
while (namedParamIdx < functionType.namedParameters.length) {
- _NamedParameter param = functionType.namedParameters[namedParamIdx];
+ _NamedParameter param =
+ functionType.namedParameters._getUnchecked(namedParamIdx);
if (namedArgIdx * 2 >= namedArguments.length) {
if (param.isRequired) {
@@ -1073,7 +1100,8 @@
continue;
}
- String argName = _symbolToString(namedArguments[namedArgIdx * 2] as Symbol);
+ String argName = _symbolToString(
+ namedArguments._getUnchecked(namedArgIdx * 2) as Symbol);
final cmp = argName.compareTo(param.name);
@@ -1116,9 +1144,11 @@
if (!typeArguments.isEmpty) {
for (int i = 0; i < typeArguments.length; i += 1) {
- final typeArgument = typeArguments[i];
+ final typeArgument = typeArguments._getUnchecked(i);
final paramBound = _TypeUniverse.substituteTypeArgument(
- functionType.typeParameterBounds[i], typeArguments, functionType);
+ functionType.typeParameterBounds._getUnchecked(i),
+ typeArguments,
+ functionType);
if (!_typeUniverse.isSubtype(typeArgument, null, paramBound, null)) {
final stackTrace = StackTrace.current;
final typeError = _TypeError.fromMessageAndStackTrace(
@@ -1135,8 +1165,8 @@
// Check positional arguments
for (int i = 0; i < positionalArguments.length; i += 1) {
- final Object? arg = positionalArguments[i];
- final _Type paramTy = functionType.positionalParameters[i];
+ final Object? arg = positionalArguments._getUnchecked(i);
+ final _Type paramTy = functionType.positionalParameters._getUnchecked(i);
if (!_isSubtype(arg, paramTy)) {
// TODO(50991): Positional parameter names not available in runtime
_TypeError._throwArgumentTypeCheckError(
@@ -1149,11 +1179,13 @@
int namedParamIdx = 0;
int namedArgIdx = 0;
while (namedArgIdx * 2 < namedArguments.length) {
- final String argName =
- _symbolToString(namedArguments[namedArgIdx * 2] as Symbol);
- if (argName == functionType.namedParameters[namedParamIdx].name) {
- final arg = namedArguments[namedArgIdx * 2 + 1];
- final paramTy = functionType.namedParameters[namedParamIdx].type;
+ final String argName = _symbolToString(
+ namedArguments._getUnchecked(namedArgIdx * 2) as Symbol);
+ if (argName ==
+ functionType.namedParameters._getUnchecked(namedParamIdx).name) {
+ final arg = namedArguments._getUnchecked(namedArgIdx * 2 + 1);
+ final paramTy =
+ functionType.namedParameters._getUnchecked(namedParamIdx).type;
if (!_isSubtype(arg, paramTy)) {
_TypeError._throwArgumentTypeCheckError(
arg, paramTy, argName, StackTrace.current);
