[vm] Simplify evaluation of asserts

Since Dart 2, assert statements only accept bool conditions,
so evaluation of the assert condition can be simplified in the VM.

TEST=existing

Change-Id: I0f54ad66b9d9aef707fef4eac192128a3994e7c9
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/425920
Reviewed-by: Alexander Aprelev <[email protected]>
Commit-Queue: Alexander Markov <[email protected]>

Author: alexmarkov

runtime/lib/errors.cc

@@ -11,18 +11,10 @@
 
 namespace dart {
 
+#if !defined(DART_PRECOMPILED_RUNTIME)
 // Scan the stack until we hit the first function in the _AssertionError
 // class. We then return the next frame's script taking inlining into account.
 static ScriptPtr FindScript(DartFrameIterator* iterator) {
-#if defined(DART_PRECOMPILED_RUNTIME)
-  // The precompiled runtime faces two issues in recovering the correct
-  // assertion text. First, the precompiled runtime does not include
-  // the inlining meta-data so we cannot walk the inline-aware stack trace.
-  // Second, the script text itself is missing so whatever script is returned
-  // from here will be missing the assertion expression text.
-  iterator->NextFrame();  // Skip _AssertionError._evaluateAssertion frame
-  return Exceptions::GetCallerScript(iterator);
-#else
   StackFrame* stack_frame = iterator->NextFrame();
   Code& code = Code::Handle();
   Function& func = Function::Handle();
@@ -60,15 +52,18 @@ static ScriptPtr FindScript(DartFrameIterator* iterator) {
   }
   UNREACHABLE();
   return Script::null();
-#endif  // defined(DART_PRECOMPILED_RUNTIME)
 }
+#endif  // !defined(DART_PRECOMPILED_RUNTIME)
 
 // Allocate and throw a new AssertionError.
 // Arg0: index of the first token of the failed assertion.
 // Arg1: index of the first token after the failed assertion.
 // Arg2: Message object or null.
 // Return value: none, throws an exception.
 DEFINE_NATIVE_ENTRY(AssertionError_throwNew, 0, 3) {
+#if defined(DART_PRECOMPILED_RUNTIME)
+  UNREACHABLE();
+#else
   // No need to type check the arguments. This function can only be called
   // internally from the VM.
   const TokenPosition assertion_start = TokenPosition::Deserialize(
@@ -114,6 +109,7 @@ DEFINE_NATIVE_ENTRY(AssertionError_throwNew, 0, 3) {
   Exceptions::ThrowByType(Exceptions::kAssertion, args);
   UNREACHABLE();
   return Object::null();
+#endif
 }
 
 // Allocate and throw a new AssertionError.

runtime/vm/compiler/frontend/kernel_binary_flowgraph.cc

@@ -1521,10 +1521,6 @@ Fragment StreamingFlowGraphBuilder::Return(TokenPosition position) {
                                      /*omit_result_type_check=*/false);
 }
 
-Fragment StreamingFlowGraphBuilder::EvaluateAssertion() {
-  return flow_graph_builder_->EvaluateAssertion();
-}
-
 Fragment StreamingFlowGraphBuilder::RethrowException(TokenPosition position,
                                                      int catch_try_index) {
   return flow_graph_builder_->RethrowException(position, catch_try_index);
@@ -4626,28 +4622,22 @@ Fragment StreamingFlowGraphBuilder::BuildAssertStatement(
   TargetEntryInstr* otherwise;
 
   Fragment instructions;
-  // Asserts can be of the following two kinds:
-  //
-  //    * `assert(expr)`
-  //    * `assert(() { ... })`
-  //
-  // The call to `_AssertionError._evaluateAssertion()` will take care of both
-  // and returns a boolean.
   instructions += BuildExpression(position);  // read condition.
 
   const TokenPosition condition_start_offset =
       ReadPosition();  // read condition start offset.
   const TokenPosition condition_end_offset =
       ReadPosition();  // read condition end offset.
 
-  instructions += EvaluateAssertion();
   instructions += RecordCoverage(condition_start_offset);
   instructions += Constant(Bool::True());
   instructions += BranchIfEqual(&then, &otherwise);
 
   const Class& klass =
       Class::ZoneHandle(Z, Library::LookupCoreClass(Symbols::AssertionError()));
   ASSERT(!klass.IsNull());
+  const auto& error = klass.EnsureIsFinalized(thread());
+  ASSERT(error == Error::null());
 
   Fragment otherwise_fragment(otherwise);
   if (CompilerState::Current().is_aot()) {

runtime/vm/compiler/frontend/kernel_binary_flowgraph.h

@@ -158,7 +158,6 @@ class StreamingFlowGraphBuilder : public KernelReaderHelper {
   Fragment LoadLocal(LocalVariable* variable);
   IndirectGotoInstr* IndirectGoto(intptr_t target_count);
   Fragment Return(TokenPosition position);
-  Fragment EvaluateAssertion();
   Fragment RethrowException(TokenPosition position, int catch_try_index);
   Fragment ThrowNoSuchMethodError(TokenPosition position,
                                   const Function& target,

runtime/vm/compiler/frontend/kernel_to_il.cc

@@ -2281,19 +2281,6 @@ bool FlowGraphBuilder::NeedsDebugStepCheck(Value* value,
   return false;
 }
 
-Fragment FlowGraphBuilder::EvaluateAssertion() {
-  const Class& klass =
-      Class::ZoneHandle(Z, Library::LookupCoreClass(Symbols::AssertionError()));
-  ASSERT(!klass.IsNull());
-  const auto& error = klass.EnsureIsFinalized(H.thread());
-  ASSERT(error == Error::null());
-  const Function& target = Function::ZoneHandle(
-      Z, klass.LookupStaticFunctionAllowPrivate(Symbols::EvaluateAssertion()));
-  ASSERT(!target.IsNull());
-  return StaticCall(TokenPosition::kNoSource, target, /* argument_count = */ 1,
-                    ICData::kStatic);
-}
-
 Fragment FlowGraphBuilder::CheckAssignable(const AbstractType& dst_type,
                                            const String& dst_name,
                                            AssertAssignableInstr::Kind kind,

runtime/vm/compiler/frontend/kernel_to_il.h

@@ -277,7 +277,6 @@ class FlowGraphBuilder : public BaseFlowGraphBuilder {
   Fragment BuildImplicitClosureCreation(TokenPosition position,
                                         const Function& target);
 
-  Fragment EvaluateAssertion();
   Fragment CheckVariableTypeInCheckedMode(const AbstractType& dst_type,
                                           const String& name_symbol);
   Fragment CheckAssignable(

runtime/vm/symbols.h

@@ -100,7 +100,6 @@ class ObjectPointerVisitor;
   V(EqualOperator, "==")                                                       \
   V(Error, "Error")                                                            \
   V(EvalSourceUri, "evaluate:source")                                          \
-  V(EvaluateAssertion, "_evaluateAssertion")                                   \
   V(ExceptionHandlers, "ExceptionHandlers")                                    \
   V(ExceptionVar, ":exception_var")                                            \
   V(Expando, "Expando")                                                        \

sdk/lib/_internal/vm/lib/errors_patch.dart

@@ -66,20 +66,6 @@ class _AssertionError extends Error implements AssertionError {
     Object? message,
   );
 
-  @pragma("vm:entry-point", "call")
-  static bool _evaluateAssertion(condition) {
-    if (identical(condition, true) || identical(condition, false)) {
-      return condition;
-    }
-    if (condition is _Closure) {
-      return (condition as dynamic Function())();
-    }
-    if (condition is Function) {
-      condition = (condition as dynamic Function())();
-    }
-    return condition;
-  }
-
   String get _messageString {
     final msg = message;
     if (msg == null) return "is not true.";