async Task <IVariableInformation> EvaluateLldbExpressionWithMetricsAsync(
VsExpression expression, IVariableInformation variable, NatvisScope natvisScope,
string displayName, ExpressionEvaluationStrategy strategy,
ExpressionEvaluationRecorder.StepsRecorder stepsRecorder)
{
bool variableReplaced = false;
expression = expression.MapValue(
v => ReplaceScopedNames(v, natvisScope?.ScopedNames, out variableReplaced));
var lldbErrors = new List <string>();
// A helper lambda function to construct an exception given the list of lldb errors.
Func <IList <string>, ExpressionEvaluationFailed> createExpressionEvaluationException =
errors =>
{
var exceptionMsg =
$"Failed to evaluate expression, display name: {displayName}, " +
$"expression: {expression}";
errors = errors.Where(error => !string.IsNullOrEmpty(error)).ToList();
if (errors.Any())
{
exceptionMsg += $", info: {{{string.Join("; ", errors)}}}";
}
return(new ExpressionEvaluationFailed(exceptionMsg));
};
if (strategy == ExpressionEvaluationStrategy.LLDB_EVAL ||
strategy == ExpressionEvaluationStrategy.LLDB_EVAL_WITH_FALLBACK)
{
IVariableInformation value;
LldbEvalErrorCode errorCode;
using (var step = stepsRecorder.NewStep(ExpressionEvaluationEngine.LLDB_EVAL))
{
value = await variable.EvaluateExpressionLldbEvalAsync(
displayName, expression, natvisScope.ContextVariables);
errorCode = (LldbEvalErrorCode)Enum.ToObject(typeof(LldbEvalErrorCode),
value.ErrorCode);
step.Finalize(errorCode);
}
if (errorCode == LldbEvalErrorCode.Ok)
{
value.FallbackValueFormat = variable.FallbackValueFormat;
return(value);
}
lldbErrors.Add(value?.ErrorMessage);
if (errorCode == LldbEvalErrorCode.InvalidNumericLiteral ||
errorCode == LldbEvalErrorCode.InvalidOperandType ||
errorCode == LldbEvalErrorCode.UndeclaredIdentifier)
{
// In the case of a well-known error, there's no need to fallback to
// LLDB, as it will fail with the same error.
throw createExpressionEvaluationException(lldbErrors);
}
}
if (strategy == ExpressionEvaluationStrategy.LLDB)
{
// If lldb-eval is not enabled, try to interpret the expression as member access
// before using LLDB to evaluate the expression in the context of the variable.
IVariableInformation value;
LLDBErrorCode errorCode;
using (var step =
stepsRecorder.NewStep(ExpressionEvaluationEngine.LLDB_VARIABLE_PATH))
{
value = GetValueForMemberAccessExpression(variable, expression, displayName);
errorCode = value != null && !value.Error
? LLDBErrorCode.OK
: LLDBErrorCode.ERROR;
step.Finalize(errorCode);
}
if (errorCode == LLDBErrorCode.OK)
{
value.FallbackValueFormat = variable.FallbackValueFormat;
return(value);
}
lldbErrors.Add(value?.ErrorMessage);
}
if (strategy == ExpressionEvaluationStrategy.LLDB ||
strategy == ExpressionEvaluationStrategy.LLDB_EVAL_WITH_FALLBACK)
{
IVariableInformation value;
LLDBErrorCode errorCode;
using (var step = stepsRecorder.NewStep(ExpressionEvaluationEngine.LLDB))
{
value = await EvaluateExpressionInVariableScopeAsync(
variable, expression, displayName);
errorCode = value != null && !value.Error
? LLDBErrorCode.OK
: LLDBErrorCode.ERROR;
step.Finalize(errorCode);
}
if (errorCode == LLDBErrorCode.OK)
{
value.FallbackValueFormat = variable.FallbackValueFormat;
return(value);
}
lldbErrors.Add(value?.ErrorMessage);
}
throw createExpressionEvaluationException(lldbErrors);
}