Add support for configurable warnings (backport #3414)

core/src/main/mima-filters/3.6.0.backwards.excludes

@@ -0,0 +1,4 @@
+# SourceInfo is sealed
+ProblemFilters.exclude[ReversedMissingMethodProblem]("chisel3.experimental.SourceInfo.filenameOption")
+# ErrorEntry is private
+ProblemFilters.exclude[DirectMissingMethodProblem]("chisel3.internal.ErrorEntry.serialize")

core/src/main/scala/chisel3/Bits.scala

@@ -16,7 +16,7 @@ import chisel3.internal.sourceinfo.{
 import chisel3.internal.firrtl.PrimOp._
 import _root_.firrtl.{ir => firrtlir}
 import _root_.firrtl.{constraint => firrtlconstraint}
-import chisel3.internal.{castToInt, Builder}
+import chisel3.internal.{castToInt, Builder, Warning, WarningID}
 
 /** Exists to unify common interfaces of [[Bits]] and [[Reset]].
   *
@@ -154,9 +154,11 @@ sealed abstract class Bits(private[chisel3] val width: Width) extends Element wi
       } else {
         x.widthOption.foreach { xWidth =>
           if (xWidth >= 31 || (1 << (xWidth - 1)) >= thisWidth) {
-            Builder.warning(s"Dynamic index with width $xWidth is too large for extractee of width $thisWidth")
+            val msg = s"Dynamic index with width $xWidth is too large for extractee of width $thisWidth"
+            Builder.warning(Warning(WarningID.DynamicBitSelectTooWide, msg))
           } else if ((1 << xWidth) < thisWidth) {
-            Builder.warning(s"Dynamic index with width $xWidth is too small for extractee of width $thisWidth")
+            val msg = s"Dynamic index with width $xWidth is too small for extractee of width $thisWidth"
+            Builder.warning(Warning(WarningID.DynamicBitSelectTooNarrow, msg))
           }
         }
       }

core/src/main/scala/chisel3/ChiselEnum.scala

@@ -11,7 +11,16 @@ import chisel3.internal.Builder.pushOp
 import chisel3.internal.firrtl.PrimOp._
 import chisel3.internal.firrtl._
 import chisel3.internal.sourceinfo._
-import chisel3.internal.{throwException, Binding, Builder, BuilderContextCache, ChildBinding, ConstrainedBinding}
+import chisel3.internal.{
+  throwException,
+  Binding,
+  Builder,
+  BuilderContextCache,
+  ChildBinding,
+  ConstrainedBinding,
+  Warning,
+  WarningID
+}
 
 import chisel3.experimental.EnumAnnotations._
 
@@ -315,10 +324,11 @@ abstract class ChiselEnum {
     } else if (n.getWidth > this.getWidth) {
       throwException(s"The UInt being cast to $enumTypeName is wider than $enumTypeName's width ($getWidth)")
     } else {
+      // TODO fold this into warning filters
       if (!Builder.suppressEnumCastWarning && warn && !this.isTotal) {
-        Builder.warning(
+        val msg =
           s"Casting non-literal UInt to $enumTypeName. You can use $enumTypeName.safe to cast without this warning."
-        )
+        Builder.warning(Warning(WarningID.UnsafeUIntCastToEnum, msg))
       }
       val glue = Wire(new UnsafeEnum(width))
       glue := n

core/src/main/scala/chisel3/experimental/SourceInfo.scala

@@ -27,10 +27,14 @@ sealed trait SourceInfo {
     * Make a useful message if SourceInfo is available, nothing otherwise
     */
   def makeMessage(f: String => String): String
+
+  /** The filename for the originating source file, if known */
+  def filenameOption: Option[String]
 }
 
 sealed trait NoSourceInfo extends SourceInfo {
   def makeMessage(f: String => String): String = ""
+  def filenameOption: Option[String] = None
 }
 
 /** For when source info can't be generated because of a technical limitation, like for Reg because
@@ -46,6 +50,49 @@ case object DeprecatedSourceInfo extends NoSourceInfo
   */
 case class SourceLine(filename: String, line: Int, col: Int) extends SourceInfo {
   def makeMessage(f: String => String): String = f(s"@[$filename $line:$col]")
+  def filenameOption: Option[String] = Some(filename)
+}
+
+/** Source locator with a line but no column, derived from a stack trace
+  *
+  * Only used for warning and error reporting when no [[SourceLine]] is available
+  */
+private[chisel3] case class SourceLineNoCol(filename: String, line: Int) extends SourceInfo {
+  def makeMessage(f: String => String): String = f(s"@[$filename $line]")
+  def filenameOption: Option[String] = Some(filename)
+}
+private[chisel3] object SourceLineNoCol {
+
+  /** Returns the best guess at the first stack frame that belongs to user code.
+    */
+  private def getUserLineNumber: Option[StackTraceElement] = {
+    def isChiselClassname(className: String): Boolean = {
+      // List of classpath prefixes that are Chisel internals and should be ignored when looking for user code
+      // utils are not part of internals and errors there can be reported
+      val chiselPrefixes = Set(
+        "java.",
+        "scala.",
+        "chisel3.",
+        "chisel3.internal.",
+        "chisel3.experimental.",
+        "chisel3.package$" // for some compatibility / deprecated types
+      )
+      !chiselPrefixes.filter(className.startsWith(_)).isEmpty
+    }
+
+    Thread
+      .currentThread()
+      .getStackTrace
+      .toList
+      .dropWhile(
+        // Get rid of everything in Chisel core
+        ste => isChiselClassname(ste.getClassName)
+      )
+      .headOption
+  }
+
+  def materialize: Option[SourceLineNoCol] =
+    getUserLineNumber.map { elt => new SourceLineNoCol(elt.getFileName, elt.getLineNumber) }
 }
 
 object SourceInfo {

core/src/main/scala/chisel3/experimental/hierarchy/core/Definition.scala

@@ -103,7 +103,7 @@ object Definition extends SourceInfoDoc {
   ): Definition[T] = {
     val dynamicContext = {
       val context = Builder.captureContext()
-      new DynamicContext(Nil, context.throwOnFirstError, context.warningsAsErrors, context.sourceRoots)
+      new DynamicContext(Nil, context.throwOnFirstError, context.warningFilters, context.sourceRoots)
     }
     Builder.globalNamespace.copyTo(dynamicContext.globalNamespace)
     dynamicContext.inDefinition = true

core/src/main/scala/chisel3/internal/Builder.scala

@@ -427,7 +427,7 @@ private[chisel3] class ChiselContext() {
 private[chisel3] class DynamicContext(
   val annotationSeq:     AnnotationSeq,
   val throwOnFirstError: Boolean,
-  val warningsAsErrors:  Boolean,
+  val warningFilters:    Seq[WarningFilter],
   val sourceRoots:       Seq[File]) {
   val importDefinitionAnnos = annotationSeq.collect { case a: ImportDefinitionAnnotation[_] => a }
 
@@ -487,7 +487,7 @@ private[chisel3] class DynamicContext(
   var whenStack:            List[WhenContext] = Nil
   var currentClock:         Option[Clock] = None
   var currentReset:         Option[Reset] = None
-  val errors = new ErrorLog(warningsAsErrors, sourceRoots)
+  val errors = new ErrorLog(warningFilters, sourceRoots, throwOnFirstError)
   val namingStack = new NamingStack
 
   // Used to indicate if this is the top-level module of full elaboration, or from a Definition
@@ -778,16 +778,16 @@ private[chisel3] object Builder extends LazyLogging {
   def errors: ErrorLog = dynamicContext.errors
   def error(m: => String)(implicit sourceInfo: SourceInfo): Unit = {
     // If --throw-on-first-error is requested, throw an exception instead of aggregating errors
-    if (dynamicContextVar.value.isDefined && !dynamicContextVar.value.get.throwOnFirstError) {
+    if (dynamicContextVar.value.isDefined) {
       errors.error(m, sourceInfo)
     } else {
       throwException(m)
     }
   }
-  def warning(m: => String)(implicit sourceInfo: SourceInfo): Unit =
-    if (dynamicContextVar.value.isDefined) errors.warning(m, sourceInfo)
-  def warningNoLoc(m: => String): Unit = if (dynamicContextVar.value.isDefined) errors.warningNoLoc(m)
-  def deprecated(m:   => String, location: Option[String] = None): Unit =
+  def warning(warning: Warning): Unit =
+    if (dynamicContextVar.value.isDefined) errors.warning(warning)
+
+  def deprecated(m: => String, location: Option[String] = None): Unit =
     if (dynamicContextVar.value.isDefined) errors.deprecated(m, location)
 
   /** Record an exception as an error, and throw it.