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authorChick Markley2020-09-16 18:52:16 -0700
committerGitHub2020-09-16 18:52:16 -0700
commitecb96e83324ea17cf38b7b90753d745d3c7f51bd (patch)
tree98b2aacab28edc29fadcf9d02b59848c4a9dc1ee /src/main
parent0c646459b52394e8a388143cee324b8af3dc7c09 (diff)
Change to Apache 2.0 License (#1901)
Diffstat (limited to 'src/main')
-rw-r--r--src/main/antlr4/FIRRTL.g42
-rw-r--r--src/main/proto/firrtl.proto2
-rw-r--r--src/main/scala/firrtl/AddDescriptionNodes.scala2
-rw-r--r--src/main/scala/firrtl/Compiler.scala2
-rw-r--r--src/main/scala/firrtl/DependencyAPIMigration.scala2
-rw-r--r--src/main/scala/firrtl/Driver.scala2
-rw-r--r--src/main/scala/firrtl/EmissionOption.scala2
-rw-r--r--src/main/scala/firrtl/Emitter.scala2
-rw-r--r--src/main/scala/firrtl/ExecutionOptionsManager.scala2
-rw-r--r--src/main/scala/firrtl/FileUtils.scala2
-rw-r--r--src/main/scala/firrtl/FirrtlException.scala2
-rw-r--r--src/main/scala/firrtl/Implicits.scala2
-rw-r--r--src/main/scala/firrtl/LexerHelper.scala2
-rw-r--r--src/main/scala/firrtl/LoweringCompilers.scala2
-rw-r--r--src/main/scala/firrtl/Mappers.scala2
-rw-r--r--src/main/scala/firrtl/Namespace.scala2
-rw-r--r--src/main/scala/firrtl/Parser.scala2
-rw-r--r--src/main/scala/firrtl/PrimOps.scala2
-rw-r--r--src/main/scala/firrtl/RenameMap.scala2
-rw-r--r--src/main/scala/firrtl/Utils.scala2
-rw-r--r--src/main/scala/firrtl/Visitor.scala2
-rw-r--r--src/main/scala/firrtl/WIR.scala2
-rw-r--r--src/main/scala/firrtl/analyses/CircuitGraph.scala2
-rw-r--r--src/main/scala/firrtl/analyses/ConnectionGraph.scala2
-rw-r--r--src/main/scala/firrtl/analyses/GetNamespace.scala2
-rw-r--r--src/main/scala/firrtl/analyses/IRLookup.scala2
-rw-r--r--src/main/scala/firrtl/analyses/InstanceGraph.scala2
-rw-r--r--src/main/scala/firrtl/analyses/InstanceKeyGraph.scala2
-rw-r--r--src/main/scala/firrtl/analyses/NodeCount.scala2
-rw-r--r--src/main/scala/firrtl/analyses/SymbolTable.scala2
-rw-r--r--src/main/scala/firrtl/annotations/Annotation.scala2
-rw-r--r--src/main/scala/firrtl/annotations/AnnotationUtils.scala2
-rw-r--r--src/main/scala/firrtl/annotations/JsonProtocol.scala2
-rw-r--r--src/main/scala/firrtl/annotations/LoadMemoryAnnotation.scala2
-rw-r--r--src/main/scala/firrtl/annotations/MemoryInitAnnotation.scala2
-rw-r--r--src/main/scala/firrtl/annotations/PresetAnnotations.scala2
-rw-r--r--src/main/scala/firrtl/annotations/Target.scala2
-rw-r--r--src/main/scala/firrtl/annotations/TargetToken.scala2
-rw-r--r--src/main/scala/firrtl/annotations/analysis/DuplicationHelper.scala2
-rw-r--r--src/main/scala/firrtl/annotations/transforms/CleanupNamedTargets.scala2
-rw-r--r--src/main/scala/firrtl/annotations/transforms/EliminateTargetPaths.scala2
-rw-r--r--src/main/scala/firrtl/backends/experimental/smt/Btor2Serializer.scala2
-rw-r--r--src/main/scala/firrtl/backends/experimental/smt/FirrtlExpressionSemantics.scala2
-rw-r--r--src/main/scala/firrtl/backends/experimental/smt/FirrtlToTransitionSystem.scala2
-rw-r--r--src/main/scala/firrtl/backends/experimental/smt/SMTEmitter.scala2
-rw-r--r--src/main/scala/firrtl/backends/experimental/smt/SMTExpr.scala2
-rw-r--r--src/main/scala/firrtl/backends/experimental/smt/SMTExprVisitor.scala2
-rw-r--r--src/main/scala/firrtl/backends/experimental/smt/SMTLibSerializer.scala2
-rw-r--r--src/main/scala/firrtl/backends/experimental/smt/SMTTransitionSystemEncoder.scala2
-rw-r--r--src/main/scala/firrtl/backends/experimental/smt/StutteringClockTransform.scala2
-rw-r--r--src/main/scala/firrtl/checks/CheckResets.scala2
-rw-r--r--src/main/scala/firrtl/constraint/Constraint.scala2
-rw-r--r--src/main/scala/firrtl/constraint/ConstraintSolver.scala2
-rw-r--r--src/main/scala/firrtl/constraint/Inequality.scala2
-rw-r--r--src/main/scala/firrtl/constraint/IsAdd.scala2
-rw-r--r--src/main/scala/firrtl/constraint/IsFloor.scala2
-rw-r--r--src/main/scala/firrtl/constraint/IsKnown.scala2
-rw-r--r--src/main/scala/firrtl/constraint/IsMax.scala2
-rw-r--r--src/main/scala/firrtl/constraint/IsMin.scala2
-rw-r--r--src/main/scala/firrtl/constraint/IsMul.scala2
-rw-r--r--src/main/scala/firrtl/constraint/IsNeg.scala2
-rw-r--r--src/main/scala/firrtl/constraint/IsPow.scala2
-rw-r--r--src/main/scala/firrtl/constraint/IsVar.scala2
-rw-r--r--src/main/scala/firrtl/features/LetterCaseTransform.scala2
-rw-r--r--src/main/scala/firrtl/graph/DiGraph.scala2
-rw-r--r--src/main/scala/firrtl/graph/EdgeData.scala2
-rw-r--r--src/main/scala/firrtl/graph/EulerTour.scala2
-rw-r--r--src/main/scala/firrtl/graph/RenderDiGraph.scala2
-rw-r--r--src/main/scala/firrtl/ir/IR.scala2
-rw-r--r--src/main/scala/firrtl/ir/Serializer.scala2
-rw-r--r--src/main/scala/firrtl/ir/StructuralHash.scala2
-rw-r--r--src/main/scala/firrtl/options/DependencyManager.scala2
-rw-r--r--src/main/scala/firrtl/options/Exceptions.scala2
-rw-r--r--src/main/scala/firrtl/options/ExitCodes.scala2
-rw-r--r--src/main/scala/firrtl/options/OptionParser.scala2
-rw-r--r--src/main/scala/firrtl/options/OptionsView.scala2
-rw-r--r--src/main/scala/firrtl/options/Phase.scala2
-rw-r--r--src/main/scala/firrtl/options/Registration.scala2
-rw-r--r--src/main/scala/firrtl/options/Shell.scala2
-rw-r--r--src/main/scala/firrtl/options/Stage.scala2
-rw-r--r--src/main/scala/firrtl/options/StageAnnotations.scala2
-rw-r--r--src/main/scala/firrtl/options/StageOptions.scala2
-rw-r--r--src/main/scala/firrtl/options/StageUtils.scala2
-rw-r--r--src/main/scala/firrtl/options/package.scala2
-rw-r--r--src/main/scala/firrtl/options/phases/AddDefaults.scala2
-rw-r--r--src/main/scala/firrtl/options/phases/Checks.scala2
-rw-r--r--src/main/scala/firrtl/options/phases/ConvertLegacyAnnotations.scala2
-rw-r--r--src/main/scala/firrtl/options/phases/DeletedWrapper.scala2
-rw-r--r--src/main/scala/firrtl/options/phases/GetIncludes.scala2
-rw-r--r--src/main/scala/firrtl/options/phases/WriteOutputAnnotations.scala2
-rw-r--r--src/main/scala/firrtl/package.scala2
-rw-r--r--src/main/scala/firrtl/passes/CInferMDir.scala2
-rw-r--r--src/main/scala/firrtl/passes/CheckChirrtl.scala2
-rw-r--r--src/main/scala/firrtl/passes/CheckFlows.scala2
-rw-r--r--src/main/scala/firrtl/passes/CheckHighForm.scala2
-rw-r--r--src/main/scala/firrtl/passes/CheckInitialization.scala2
-rw-r--r--src/main/scala/firrtl/passes/CheckTypes.scala2
-rw-r--r--src/main/scala/firrtl/passes/CheckWidths.scala2
-rw-r--r--src/main/scala/firrtl/passes/CommonSubexpressionElimination.scala2
-rw-r--r--src/main/scala/firrtl/passes/ConvertFixedToSInt.scala2
-rw-r--r--src/main/scala/firrtl/passes/ExpandConnects.scala2
-rw-r--r--src/main/scala/firrtl/passes/ExpandWhens.scala2
-rw-r--r--src/main/scala/firrtl/passes/InferBinaryPoints.scala2
-rw-r--r--src/main/scala/firrtl/passes/InferTypes.scala2
-rw-r--r--src/main/scala/firrtl/passes/InferWidths.scala2
-rw-r--r--src/main/scala/firrtl/passes/Inline.scala2
-rw-r--r--src/main/scala/firrtl/passes/Legalize.scala2
-rw-r--r--src/main/scala/firrtl/passes/LowerTypes.scala2
-rw-r--r--src/main/scala/firrtl/passes/PadWidths.scala2
-rw-r--r--src/main/scala/firrtl/passes/Pass.scala2
-rw-r--r--src/main/scala/firrtl/passes/PullMuxes.scala2
-rw-r--r--src/main/scala/firrtl/passes/RemoveAccesses.scala2
-rw-r--r--src/main/scala/firrtl/passes/RemoveCHIRRTL.scala2
-rw-r--r--src/main/scala/firrtl/passes/RemoveEmpty.scala2
-rw-r--r--src/main/scala/firrtl/passes/RemoveIntervals.scala2
-rw-r--r--src/main/scala/firrtl/passes/RemoveValidIf.scala2
-rw-r--r--src/main/scala/firrtl/passes/ReplaceAccesses.scala2
-rw-r--r--src/main/scala/firrtl/passes/ResolveFlows.scala2
-rw-r--r--src/main/scala/firrtl/passes/ResolveKinds.scala2
-rw-r--r--src/main/scala/firrtl/passes/SplitExpressions.scala2
-rw-r--r--src/main/scala/firrtl/passes/ToWorkingIR.scala2
-rw-r--r--src/main/scala/firrtl/passes/TrimIntervals.scala2
-rw-r--r--src/main/scala/firrtl/passes/Uniquify.scala2
-rw-r--r--src/main/scala/firrtl/passes/VerilogModulusCleanup.scala2
-rw-r--r--src/main/scala/firrtl/passes/VerilogPrep.scala2
-rw-r--r--src/main/scala/firrtl/passes/ZeroLengthVecs.scala2
-rw-r--r--src/main/scala/firrtl/passes/ZeroWidth.scala2
-rw-r--r--src/main/scala/firrtl/passes/clocklist/ClockList.scala2
-rw-r--r--src/main/scala/firrtl/passes/clocklist/ClockListTransform.scala2
-rw-r--r--src/main/scala/firrtl/passes/clocklist/ClockListUtils.scala2
-rw-r--r--src/main/scala/firrtl/passes/clocklist/RemoveAllButClocks.scala2
-rw-r--r--src/main/scala/firrtl/passes/memlib/DecorateMems.scala2
-rw-r--r--src/main/scala/firrtl/passes/memlib/InferReadWrite.scala2
-rw-r--r--src/main/scala/firrtl/passes/memlib/MemConf.scala2
-rw-r--r--src/main/scala/firrtl/passes/memlib/MemIR.scala2
-rw-r--r--src/main/scala/firrtl/passes/memlib/MemLibOptions.scala2
-rw-r--r--src/main/scala/firrtl/passes/memlib/MemTransformUtils.scala2
-rw-r--r--src/main/scala/firrtl/passes/memlib/MemUtils.scala2
-rw-r--r--src/main/scala/firrtl/passes/memlib/RenameAnnotatedMemoryPorts.scala2
-rw-r--r--src/main/scala/firrtl/passes/memlib/ReplaceMemMacros.scala2
-rw-r--r--src/main/scala/firrtl/passes/memlib/ReplaceMemTransform.scala2
-rw-r--r--src/main/scala/firrtl/passes/memlib/ResolveMaskGranularity.scala2
-rw-r--r--src/main/scala/firrtl/passes/memlib/ResolveMemoryReference.scala2
-rw-r--r--src/main/scala/firrtl/passes/memlib/ToMemIR.scala2
-rw-r--r--src/main/scala/firrtl/passes/memlib/VerilogMemDelays.scala2
-rw-r--r--src/main/scala/firrtl/passes/memlib/YamlUtils.scala2
-rw-r--r--src/main/scala/firrtl/passes/wiring/Wiring.scala2
-rw-r--r--src/main/scala/firrtl/passes/wiring/WiringTransform.scala2
-rw-r--r--src/main/scala/firrtl/passes/wiring/WiringUtils.scala2
-rw-r--r--src/main/scala/firrtl/proto/FromProto.scala2
-rw-r--r--src/main/scala/firrtl/proto/ToProto.scala2
-rw-r--r--src/main/scala/firrtl/stage/FirrtlAnnotations.scala2
-rw-r--r--src/main/scala/firrtl/stage/FirrtlCli.scala2
-rw-r--r--src/main/scala/firrtl/stage/FirrtlOptions.scala2
-rw-r--r--src/main/scala/firrtl/stage/FirrtlStage.scala2
-rw-r--r--src/main/scala/firrtl/stage/FirrtlStageUtils.scala2
-rw-r--r--src/main/scala/firrtl/stage/Forms.scala2
-rw-r--r--src/main/scala/firrtl/stage/TransformManager.scala2
-rw-r--r--src/main/scala/firrtl/stage/package.scala2
-rw-r--r--src/main/scala/firrtl/stage/phases/AddCircuit.scala2
-rw-r--r--src/main/scala/firrtl/stage/phases/AddDefaults.scala2
-rw-r--r--src/main/scala/firrtl/stage/phases/AddImplicitEmitter.scala2
-rw-r--r--src/main/scala/firrtl/stage/phases/AddImplicitOutputFile.scala2
-rw-r--r--src/main/scala/firrtl/stage/phases/CatchExceptions.scala2
-rw-r--r--src/main/scala/firrtl/stage/phases/Checks.scala2
-rw-r--r--src/main/scala/firrtl/stage/phases/Compiler.scala2
-rw-r--r--src/main/scala/firrtl/stage/phases/ConvertCompilerAnnotations.scala2
-rw-r--r--src/main/scala/firrtl/stage/phases/DriverCompatibility.scala2
-rw-r--r--src/main/scala/firrtl/stage/phases/WriteEmitted.scala2
-rw-r--r--src/main/scala/firrtl/stage/transforms/CatchCustomTransformExceptions.scala2
-rw-r--r--src/main/scala/firrtl/stage/transforms/CheckScalaVersion.scala2
-rw-r--r--src/main/scala/firrtl/stage/transforms/Compiler.scala2
-rw-r--r--src/main/scala/firrtl/stage/transforms/ExpandPrepares.scala2
-rw-r--r--src/main/scala/firrtl/stage/transforms/TrackTransforms.scala2
-rw-r--r--src/main/scala/firrtl/stage/transforms/UpdateAnnotations.scala2
-rw-r--r--src/main/scala/firrtl/stage/transforms/WrappedTransform.scala2
-rw-r--r--src/main/scala/firrtl/transforms/BlackBoxSourceHelper.scala2
-rw-r--r--src/main/scala/firrtl/transforms/CheckCombLoops.scala2
-rw-r--r--src/main/scala/firrtl/transforms/CombineCats.scala2
-rw-r--r--src/main/scala/firrtl/transforms/ConstantPropagation.scala2
-rw-r--r--src/main/scala/firrtl/transforms/DeadCodeElimination.scala2
-rw-r--r--src/main/scala/firrtl/transforms/Dedup.scala2
-rw-r--r--src/main/scala/firrtl/transforms/FixAddingNegativeLiteralsTransform.scala2
-rw-r--r--src/main/scala/firrtl/transforms/Flatten.scala2
-rw-r--r--src/main/scala/firrtl/transforms/FlattenRegUpdate.scala2
-rw-r--r--src/main/scala/firrtl/transforms/GroupComponents.scala2
-rw-r--r--src/main/scala/firrtl/transforms/IdentityTransform.scala2
-rw-r--r--src/main/scala/firrtl/transforms/InferResets.scala2
-rw-r--r--src/main/scala/firrtl/transforms/InlineBitExtractions.scala2
-rw-r--r--src/main/scala/firrtl/transforms/InlineBooleanExpressions.scala2
-rw-r--r--src/main/scala/firrtl/transforms/InlineCasts.scala2
-rw-r--r--src/main/scala/firrtl/transforms/LegalizeClocksAndAsyncResets.scala2
-rw-r--r--src/main/scala/firrtl/transforms/LegalizeReductions.scala2
-rw-r--r--src/main/scala/firrtl/transforms/ManipulateNames.scala2
-rw-r--r--src/main/scala/firrtl/transforms/OptimizationAnnotations.scala2
-rw-r--r--src/main/scala/firrtl/transforms/PropagatePresetAnnotations.scala2
-rw-r--r--src/main/scala/firrtl/transforms/RemoveKeywordCollisions.scala2
-rw-r--r--src/main/scala/firrtl/transforms/RemoveReset.scala2
-rw-r--r--src/main/scala/firrtl/transforms/RemoveWires.scala2
-rw-r--r--src/main/scala/firrtl/transforms/RenameModules.scala2
-rw-r--r--src/main/scala/firrtl/transforms/ReplaceTruncatingArithmetic.scala2
-rw-r--r--src/main/scala/firrtl/transforms/SimplifyMems.scala2
-rw-r--r--src/main/scala/firrtl/transforms/TopWiring.scala2
-rw-r--r--src/main/scala/firrtl/transforms/formal/AssertSubmoduleAssumptions.scala2
-rw-r--r--src/main/scala/firrtl/transforms/formal/ConvertAsserts.scala2
-rw-r--r--src/main/scala/firrtl/transforms/formal/RemoveVerificationStatements.scala2
-rw-r--r--src/main/scala/firrtl/transforms/package.scala2
-rw-r--r--src/main/scala/firrtl/traversals/Foreachers.scala2
-rw-r--r--src/main/scala/firrtl/util/BackendCompilationUtilities.scala2
-rw-r--r--src/main/scala/firrtl/util/ClassUtils.scala2
-rw-r--r--src/main/scala/firrtl/util/TestOptions.scala2
-rw-r--r--src/main/scala/logger/Logger.scala2
-rw-r--r--src/main/scala/logger/LoggerAnnotations.scala2
-rw-r--r--src/main/scala/logger/LoggerOptions.scala2
-rw-r--r--src/main/scala/logger/package.scala2
-rw-r--r--src/main/scala/logger/phases/AddDefaults.scala2
-rw-r--r--src/main/scala/logger/phases/Checks.scala2
-rw-r--r--src/main/scala/tutorial/lesson1-circuit-traversal/AnalyzeCircuit.scala2
-rw-r--r--src/main/scala/tutorial/lesson2-ir-fields/AnalyzeCircuit.scala2
219 files changed, 237 insertions, 201 deletions
diff --git a/src/main/antlr4/FIRRTL.g4 b/src/main/antlr4/FIRRTL.g4
index f0ea5b10..54ad8d0e 100644
--- a/src/main/antlr4/FIRRTL.g4
+++ b/src/main/antlr4/FIRRTL.g4
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
grammar FIRRTL;
diff --git a/src/main/proto/firrtl.proto b/src/main/proto/firrtl.proto
index b4c8f36d..e8451d7a 100644
--- a/src/main/proto/firrtl.proto
+++ b/src/main/proto/firrtl.proto
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0
+
syntax = "proto3";
package firrtl;
diff --git a/src/main/scala/firrtl/AddDescriptionNodes.scala b/src/main/scala/firrtl/AddDescriptionNodes.scala
index 7adb28af..9424d4a7 100644
--- a/src/main/scala/firrtl/AddDescriptionNodes.scala
+++ b/src/main/scala/firrtl/AddDescriptionNodes.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
diff --git a/src/main/scala/firrtl/Compiler.scala b/src/main/scala/firrtl/Compiler.scala
index ec09cace..fc852208 100644
--- a/src/main/scala/firrtl/Compiler.scala
+++ b/src/main/scala/firrtl/Compiler.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
diff --git a/src/main/scala/firrtl/DependencyAPIMigration.scala b/src/main/scala/firrtl/DependencyAPIMigration.scala
index dc5957f2..b62b99c5 100644
--- a/src/main/scala/firrtl/DependencyAPIMigration.scala
+++ b/src/main/scala/firrtl/DependencyAPIMigration.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
diff --git a/src/main/scala/firrtl/Driver.scala b/src/main/scala/firrtl/Driver.scala
index 28eb2d6a..52ea122e 100644
--- a/src/main/scala/firrtl/Driver.scala
+++ b/src/main/scala/firrtl/Driver.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
diff --git a/src/main/scala/firrtl/EmissionOption.scala b/src/main/scala/firrtl/EmissionOption.scala
index d097e14a..074d9c28 100644
--- a/src/main/scala/firrtl/EmissionOption.scala
+++ b/src/main/scala/firrtl/EmissionOption.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
diff --git a/src/main/scala/firrtl/Emitter.scala b/src/main/scala/firrtl/Emitter.scala
index 397956d8..c0be071e 100644
--- a/src/main/scala/firrtl/Emitter.scala
+++ b/src/main/scala/firrtl/Emitter.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
diff --git a/src/main/scala/firrtl/ExecutionOptionsManager.scala b/src/main/scala/firrtl/ExecutionOptionsManager.scala
index e673a5af..8602b984 100644
--- a/src/main/scala/firrtl/ExecutionOptionsManager.scala
+++ b/src/main/scala/firrtl/ExecutionOptionsManager.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
diff --git a/src/main/scala/firrtl/FileUtils.scala b/src/main/scala/firrtl/FileUtils.scala
index 3db86b7c..ff997168 100644
--- a/src/main/scala/firrtl/FileUtils.scala
+++ b/src/main/scala/firrtl/FileUtils.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
diff --git a/src/main/scala/firrtl/FirrtlException.scala b/src/main/scala/firrtl/FirrtlException.scala
index 6f98fda3..91d5350e 100644
--- a/src/main/scala/firrtl/FirrtlException.scala
+++ b/src/main/scala/firrtl/FirrtlException.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
diff --git a/src/main/scala/firrtl/Implicits.scala b/src/main/scala/firrtl/Implicits.scala
index fd732917..62ddf03a 100644
--- a/src/main/scala/firrtl/Implicits.scala
+++ b/src/main/scala/firrtl/Implicits.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
diff --git a/src/main/scala/firrtl/LexerHelper.scala b/src/main/scala/firrtl/LexerHelper.scala
index 3ddfc5b9..e1327cd7 100644
--- a/src/main/scala/firrtl/LexerHelper.scala
+++ b/src/main/scala/firrtl/LexerHelper.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
diff --git a/src/main/scala/firrtl/LoweringCompilers.scala b/src/main/scala/firrtl/LoweringCompilers.scala
index 90881a57..e27cafb7 100644
--- a/src/main/scala/firrtl/LoweringCompilers.scala
+++ b/src/main/scala/firrtl/LoweringCompilers.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
diff --git a/src/main/scala/firrtl/Mappers.scala b/src/main/scala/firrtl/Mappers.scala
index e9a698ae..55adf29f 100644
--- a/src/main/scala/firrtl/Mappers.scala
+++ b/src/main/scala/firrtl/Mappers.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
diff --git a/src/main/scala/firrtl/Namespace.scala b/src/main/scala/firrtl/Namespace.scala
index c036b5f7..25f4a805 100644
--- a/src/main/scala/firrtl/Namespace.scala
+++ b/src/main/scala/firrtl/Namespace.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
diff --git a/src/main/scala/firrtl/Parser.scala b/src/main/scala/firrtl/Parser.scala
index 40eaa88f..2d2bd350 100644
--- a/src/main/scala/firrtl/Parser.scala
+++ b/src/main/scala/firrtl/Parser.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
diff --git a/src/main/scala/firrtl/PrimOps.scala b/src/main/scala/firrtl/PrimOps.scala
index baa8638a..f6ff5694 100644
--- a/src/main/scala/firrtl/PrimOps.scala
+++ b/src/main/scala/firrtl/PrimOps.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
diff --git a/src/main/scala/firrtl/RenameMap.scala b/src/main/scala/firrtl/RenameMap.scala
index d85998b5..c32823b2 100644
--- a/src/main/scala/firrtl/RenameMap.scala
+++ b/src/main/scala/firrtl/RenameMap.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
diff --git a/src/main/scala/firrtl/Utils.scala b/src/main/scala/firrtl/Utils.scala
index e8a00518..ac987456 100644
--- a/src/main/scala/firrtl/Utils.scala
+++ b/src/main/scala/firrtl/Utils.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
diff --git a/src/main/scala/firrtl/Visitor.scala b/src/main/scala/firrtl/Visitor.scala
index b14c39c7..7ba8a0bf 100644
--- a/src/main/scala/firrtl/Visitor.scala
+++ b/src/main/scala/firrtl/Visitor.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
diff --git a/src/main/scala/firrtl/WIR.scala b/src/main/scala/firrtl/WIR.scala
index 4153fc74..a0b85007 100644
--- a/src/main/scala/firrtl/WIR.scala
+++ b/src/main/scala/firrtl/WIR.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
diff --git a/src/main/scala/firrtl/analyses/CircuitGraph.scala b/src/main/scala/firrtl/analyses/CircuitGraph.scala
index a1fb0f19..e13cadad 100644
--- a/src/main/scala/firrtl/analyses/CircuitGraph.scala
+++ b/src/main/scala/firrtl/analyses/CircuitGraph.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.analyses
diff --git a/src/main/scala/firrtl/analyses/ConnectionGraph.scala b/src/main/scala/firrtl/analyses/ConnectionGraph.scala
index f98cf14c..e5e3bde2 100644
--- a/src/main/scala/firrtl/analyses/ConnectionGraph.scala
+++ b/src/main/scala/firrtl/analyses/ConnectionGraph.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.analyses
diff --git a/src/main/scala/firrtl/analyses/GetNamespace.scala b/src/main/scala/firrtl/analyses/GetNamespace.scala
index ad4dab43..dddfc338 100644
--- a/src/main/scala/firrtl/analyses/GetNamespace.scala
+++ b/src/main/scala/firrtl/analyses/GetNamespace.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.analyses
diff --git a/src/main/scala/firrtl/analyses/IRLookup.scala b/src/main/scala/firrtl/analyses/IRLookup.scala
index b8528a95..e403c149 100644
--- a/src/main/scala/firrtl/analyses/IRLookup.scala
+++ b/src/main/scala/firrtl/analyses/IRLookup.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.analyses
diff --git a/src/main/scala/firrtl/analyses/InstanceGraph.scala b/src/main/scala/firrtl/analyses/InstanceGraph.scala
index 4aab9a3a..0017ff8b 100644
--- a/src/main/scala/firrtl/analyses/InstanceGraph.scala
+++ b/src/main/scala/firrtl/analyses/InstanceGraph.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.analyses
diff --git a/src/main/scala/firrtl/analyses/InstanceKeyGraph.scala b/src/main/scala/firrtl/analyses/InstanceKeyGraph.scala
index 5354888d..06c0b377 100644
--- a/src/main/scala/firrtl/analyses/InstanceKeyGraph.scala
+++ b/src/main/scala/firrtl/analyses/InstanceKeyGraph.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.analyses
diff --git a/src/main/scala/firrtl/analyses/NodeCount.scala b/src/main/scala/firrtl/analyses/NodeCount.scala
index 63571503..486c3be8 100644
--- a/src/main/scala/firrtl/analyses/NodeCount.scala
+++ b/src/main/scala/firrtl/analyses/NodeCount.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
package analyses
diff --git a/src/main/scala/firrtl/analyses/SymbolTable.scala b/src/main/scala/firrtl/analyses/SymbolTable.scala
index 36549160..3b304bc1 100644
--- a/src/main/scala/firrtl/analyses/SymbolTable.scala
+++ b/src/main/scala/firrtl/analyses/SymbolTable.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.analyses
diff --git a/src/main/scala/firrtl/annotations/Annotation.scala b/src/main/scala/firrtl/annotations/Annotation.scala
index 16f85e67..bea88e51 100644
--- a/src/main/scala/firrtl/annotations/Annotation.scala
+++ b/src/main/scala/firrtl/annotations/Annotation.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
package annotations
diff --git a/src/main/scala/firrtl/annotations/AnnotationUtils.scala b/src/main/scala/firrtl/annotations/AnnotationUtils.scala
index eccb4e13..10894b26 100644
--- a/src/main/scala/firrtl/annotations/AnnotationUtils.scala
+++ b/src/main/scala/firrtl/annotations/AnnotationUtils.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
package annotations
diff --git a/src/main/scala/firrtl/annotations/JsonProtocol.scala b/src/main/scala/firrtl/annotations/JsonProtocol.scala
index 144cd894..c284c788 100644
--- a/src/main/scala/firrtl/annotations/JsonProtocol.scala
+++ b/src/main/scala/firrtl/annotations/JsonProtocol.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
package annotations
diff --git a/src/main/scala/firrtl/annotations/LoadMemoryAnnotation.scala b/src/main/scala/firrtl/annotations/LoadMemoryAnnotation.scala
index 043c1b3b..f3300f7c 100644
--- a/src/main/scala/firrtl/annotations/LoadMemoryAnnotation.scala
+++ b/src/main/scala/firrtl/annotations/LoadMemoryAnnotation.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.annotations
diff --git a/src/main/scala/firrtl/annotations/MemoryInitAnnotation.scala b/src/main/scala/firrtl/annotations/MemoryInitAnnotation.scala
index 7cefdef8..44656e0d 100644
--- a/src/main/scala/firrtl/annotations/MemoryInitAnnotation.scala
+++ b/src/main/scala/firrtl/annotations/MemoryInitAnnotation.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.annotations
diff --git a/src/main/scala/firrtl/annotations/PresetAnnotations.scala b/src/main/scala/firrtl/annotations/PresetAnnotations.scala
index d6066aa7..32f24f13 100644
--- a/src/main/scala/firrtl/annotations/PresetAnnotations.scala
+++ b/src/main/scala/firrtl/annotations/PresetAnnotations.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
package annotations
diff --git a/src/main/scala/firrtl/annotations/Target.scala b/src/main/scala/firrtl/annotations/Target.scala
index afde84dc..137d070e 100644
--- a/src/main/scala/firrtl/annotations/Target.scala
+++ b/src/main/scala/firrtl/annotations/Target.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
package annotations
diff --git a/src/main/scala/firrtl/annotations/TargetToken.scala b/src/main/scala/firrtl/annotations/TargetToken.scala
index a4a98eed..190e85fa 100644
--- a/src/main/scala/firrtl/annotations/TargetToken.scala
+++ b/src/main/scala/firrtl/annotations/TargetToken.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.annotations
diff --git a/src/main/scala/firrtl/annotations/analysis/DuplicationHelper.scala b/src/main/scala/firrtl/annotations/analysis/DuplicationHelper.scala
index d4bac8ba..c16a2670 100644
--- a/src/main/scala/firrtl/annotations/analysis/DuplicationHelper.scala
+++ b/src/main/scala/firrtl/annotations/analysis/DuplicationHelper.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.annotations.analysis
diff --git a/src/main/scala/firrtl/annotations/transforms/CleanupNamedTargets.scala b/src/main/scala/firrtl/annotations/transforms/CleanupNamedTargets.scala
index 20304378..28f50993 100644
--- a/src/main/scala/firrtl/annotations/transforms/CleanupNamedTargets.scala
+++ b/src/main/scala/firrtl/annotations/transforms/CleanupNamedTargets.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.annotations.transforms
diff --git a/src/main/scala/firrtl/annotations/transforms/EliminateTargetPaths.scala b/src/main/scala/firrtl/annotations/transforms/EliminateTargetPaths.scala
index 596a344f..b63dd13e 100644
--- a/src/main/scala/firrtl/annotations/transforms/EliminateTargetPaths.scala
+++ b/src/main/scala/firrtl/annotations/transforms/EliminateTargetPaths.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.annotations.transforms
diff --git a/src/main/scala/firrtl/backends/experimental/smt/Btor2Serializer.scala b/src/main/scala/firrtl/backends/experimental/smt/Btor2Serializer.scala
index 66690f56..4cd5c9f7 100644
--- a/src/main/scala/firrtl/backends/experimental/smt/Btor2Serializer.scala
+++ b/src/main/scala/firrtl/backends/experimental/smt/Btor2Serializer.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
// Author: Kevin Laeufer <laeufer@cs.berkeley.edu>
package firrtl.backends.experimental.smt
diff --git a/src/main/scala/firrtl/backends/experimental/smt/FirrtlExpressionSemantics.scala b/src/main/scala/firrtl/backends/experimental/smt/FirrtlExpressionSemantics.scala
index efa89687..d85fbfe5 100644
--- a/src/main/scala/firrtl/backends/experimental/smt/FirrtlExpressionSemantics.scala
+++ b/src/main/scala/firrtl/backends/experimental/smt/FirrtlExpressionSemantics.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
// Author: Kevin Laeufer <laeufer@cs.berkeley.edu>
package firrtl.backends.experimental.smt
diff --git a/src/main/scala/firrtl/backends/experimental/smt/FirrtlToTransitionSystem.scala b/src/main/scala/firrtl/backends/experimental/smt/FirrtlToTransitionSystem.scala
index 75f6a326..41d3c6f0 100644
--- a/src/main/scala/firrtl/backends/experimental/smt/FirrtlToTransitionSystem.scala
+++ b/src/main/scala/firrtl/backends/experimental/smt/FirrtlToTransitionSystem.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
// Author: Kevin Laeufer <laeufer@cs.berkeley.edu>
package firrtl.backends.experimental.smt
diff --git a/src/main/scala/firrtl/backends/experimental/smt/SMTEmitter.scala b/src/main/scala/firrtl/backends/experimental/smt/SMTEmitter.scala
index 1c7ea42f..ca472578 100644
--- a/src/main/scala/firrtl/backends/experimental/smt/SMTEmitter.scala
+++ b/src/main/scala/firrtl/backends/experimental/smt/SMTEmitter.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
// Author: Kevin Laeufer <laeufer@cs.berkeley.edu>
package firrtl.backends.experimental.smt
diff --git a/src/main/scala/firrtl/backends/experimental/smt/SMTExpr.scala b/src/main/scala/firrtl/backends/experimental/smt/SMTExpr.scala
index ebb9e309..63692006 100644
--- a/src/main/scala/firrtl/backends/experimental/smt/SMTExpr.scala
+++ b/src/main/scala/firrtl/backends/experimental/smt/SMTExpr.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
// Author: Kevin Laeufer <laeufer@cs.berkeley.edu>
// Inspired by the uclid5 SMT library (https://github.com/uclid-org/uclid).
// And the btor2 documentation (BTOR2 , BtorMC and Boolector 3.0 by Niemetz et.al.)
diff --git a/src/main/scala/firrtl/backends/experimental/smt/SMTExprVisitor.scala b/src/main/scala/firrtl/backends/experimental/smt/SMTExprVisitor.scala
index defc787c..19f1de84 100644
--- a/src/main/scala/firrtl/backends/experimental/smt/SMTExprVisitor.scala
+++ b/src/main/scala/firrtl/backends/experimental/smt/SMTExprVisitor.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
// Author: Kevin Laeufer <laeufer@cs.berkeley.edu>
package firrtl.backends.experimental.smt
diff --git a/src/main/scala/firrtl/backends/experimental/smt/SMTLibSerializer.scala b/src/main/scala/firrtl/backends/experimental/smt/SMTLibSerializer.scala
index bd5e4d8c..7bc0a077 100644
--- a/src/main/scala/firrtl/backends/experimental/smt/SMTLibSerializer.scala
+++ b/src/main/scala/firrtl/backends/experimental/smt/SMTLibSerializer.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
// Author: Kevin Laeufer <laeufer@cs.berkeley.edu>
package firrtl.backends.experimental.smt
diff --git a/src/main/scala/firrtl/backends/experimental/smt/SMTTransitionSystemEncoder.scala b/src/main/scala/firrtl/backends/experimental/smt/SMTTransitionSystemEncoder.scala
index 4c60a1b0..f6d9a26f 100644
--- a/src/main/scala/firrtl/backends/experimental/smt/SMTTransitionSystemEncoder.scala
+++ b/src/main/scala/firrtl/backends/experimental/smt/SMTTransitionSystemEncoder.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
// Author: Kevin Laeufer <laeufer@cs.berkeley.edu>
package firrtl.backends.experimental.smt
diff --git a/src/main/scala/firrtl/backends/experimental/smt/StutteringClockTransform.scala b/src/main/scala/firrtl/backends/experimental/smt/StutteringClockTransform.scala
index 95db95ef..eac9f00a 100644
--- a/src/main/scala/firrtl/backends/experimental/smt/StutteringClockTransform.scala
+++ b/src/main/scala/firrtl/backends/experimental/smt/StutteringClockTransform.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
// Author: Kevin Laeufer <laeufer@cs.berkeley.edu>
package firrtl.backends.experimental.smt
diff --git a/src/main/scala/firrtl/checks/CheckResets.scala b/src/main/scala/firrtl/checks/CheckResets.scala
index a17e3e7b..ae300d1f 100644
--- a/src/main/scala/firrtl/checks/CheckResets.scala
+++ b/src/main/scala/firrtl/checks/CheckResets.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.checks
diff --git a/src/main/scala/firrtl/constraint/Constraint.scala b/src/main/scala/firrtl/constraint/Constraint.scala
index 1a3bc21a..87d15737 100644
--- a/src/main/scala/firrtl/constraint/Constraint.scala
+++ b/src/main/scala/firrtl/constraint/Constraint.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.constraint
diff --git a/src/main/scala/firrtl/constraint/ConstraintSolver.scala b/src/main/scala/firrtl/constraint/ConstraintSolver.scala
index 64271ae1..051a9653 100644
--- a/src/main/scala/firrtl/constraint/ConstraintSolver.scala
+++ b/src/main/scala/firrtl/constraint/ConstraintSolver.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.constraint
diff --git a/src/main/scala/firrtl/constraint/Inequality.scala b/src/main/scala/firrtl/constraint/Inequality.scala
index a01b7c85..91c989d5 100644
--- a/src/main/scala/firrtl/constraint/Inequality.scala
+++ b/src/main/scala/firrtl/constraint/Inequality.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.constraint
diff --git a/src/main/scala/firrtl/constraint/IsAdd.scala b/src/main/scala/firrtl/constraint/IsAdd.scala
index 9305db89..db2e0f15 100644
--- a/src/main/scala/firrtl/constraint/IsAdd.scala
+++ b/src/main/scala/firrtl/constraint/IsAdd.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.constraint
diff --git a/src/main/scala/firrtl/constraint/IsFloor.scala b/src/main/scala/firrtl/constraint/IsFloor.scala
index 60f049bb..48173b55 100644
--- a/src/main/scala/firrtl/constraint/IsFloor.scala
+++ b/src/main/scala/firrtl/constraint/IsFloor.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.constraint
diff --git a/src/main/scala/firrtl/constraint/IsKnown.scala b/src/main/scala/firrtl/constraint/IsKnown.scala
index 07e0531c..b11adc3a 100644
--- a/src/main/scala/firrtl/constraint/IsKnown.scala
+++ b/src/main/scala/firrtl/constraint/IsKnown.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.constraint
diff --git a/src/main/scala/firrtl/constraint/IsMax.scala b/src/main/scala/firrtl/constraint/IsMax.scala
index 0ba20c08..6c5372fa 100644
--- a/src/main/scala/firrtl/constraint/IsMax.scala
+++ b/src/main/scala/firrtl/constraint/IsMax.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.constraint
diff --git a/src/main/scala/firrtl/constraint/IsMin.scala b/src/main/scala/firrtl/constraint/IsMin.scala
index 2c5db14d..744b3561 100644
--- a/src/main/scala/firrtl/constraint/IsMin.scala
+++ b/src/main/scala/firrtl/constraint/IsMin.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.constraint
diff --git a/src/main/scala/firrtl/constraint/IsMul.scala b/src/main/scala/firrtl/constraint/IsMul.scala
index a4acd74c..da63d0f9 100644
--- a/src/main/scala/firrtl/constraint/IsMul.scala
+++ b/src/main/scala/firrtl/constraint/IsMul.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.constraint
diff --git a/src/main/scala/firrtl/constraint/IsNeg.scala b/src/main/scala/firrtl/constraint/IsNeg.scala
index 574cfd47..e2e590ae 100644
--- a/src/main/scala/firrtl/constraint/IsNeg.scala
+++ b/src/main/scala/firrtl/constraint/IsNeg.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.constraint
diff --git a/src/main/scala/firrtl/constraint/IsPow.scala b/src/main/scala/firrtl/constraint/IsPow.scala
index 2a1fb14a..92ca649f 100644
--- a/src/main/scala/firrtl/constraint/IsPow.scala
+++ b/src/main/scala/firrtl/constraint/IsPow.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.constraint
diff --git a/src/main/scala/firrtl/constraint/IsVar.scala b/src/main/scala/firrtl/constraint/IsVar.scala
index 18fb53b2..1675a6fc 100644
--- a/src/main/scala/firrtl/constraint/IsVar.scala
+++ b/src/main/scala/firrtl/constraint/IsVar.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.constraint
diff --git a/src/main/scala/firrtl/features/LetterCaseTransform.scala b/src/main/scala/firrtl/features/LetterCaseTransform.scala
index 8610d7b1..6d0c2b30 100644
--- a/src/main/scala/firrtl/features/LetterCaseTransform.scala
+++ b/src/main/scala/firrtl/features/LetterCaseTransform.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.features
diff --git a/src/main/scala/firrtl/graph/DiGraph.scala b/src/main/scala/firrtl/graph/DiGraph.scala
index 7720028c..b99c6961 100644
--- a/src/main/scala/firrtl/graph/DiGraph.scala
+++ b/src/main/scala/firrtl/graph/DiGraph.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.graph
diff --git a/src/main/scala/firrtl/graph/EdgeData.scala b/src/main/scala/firrtl/graph/EdgeData.scala
index 6a63c3b9..92ff3405 100644
--- a/src/main/scala/firrtl/graph/EdgeData.scala
+++ b/src/main/scala/firrtl/graph/EdgeData.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.graph
diff --git a/src/main/scala/firrtl/graph/EulerTour.scala b/src/main/scala/firrtl/graph/EulerTour.scala
index 5e075ae2..5268f91c 100644
--- a/src/main/scala/firrtl/graph/EulerTour.scala
+++ b/src/main/scala/firrtl/graph/EulerTour.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.graph
diff --git a/src/main/scala/firrtl/graph/RenderDiGraph.scala b/src/main/scala/firrtl/graph/RenderDiGraph.scala
index 45be3a8f..d726c8b4 100644
--- a/src/main/scala/firrtl/graph/RenderDiGraph.scala
+++ b/src/main/scala/firrtl/graph/RenderDiGraph.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.graph
diff --git a/src/main/scala/firrtl/ir/IR.scala b/src/main/scala/firrtl/ir/IR.scala
index 2536a77e..a26a2a94 100644
--- a/src/main/scala/firrtl/ir/IR.scala
+++ b/src/main/scala/firrtl/ir/IR.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
package ir
diff --git a/src/main/scala/firrtl/ir/Serializer.scala b/src/main/scala/firrtl/ir/Serializer.scala
index 08ea1445..4a1bfbed 100644
--- a/src/main/scala/firrtl/ir/Serializer.scala
+++ b/src/main/scala/firrtl/ir/Serializer.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.ir
diff --git a/src/main/scala/firrtl/ir/StructuralHash.scala b/src/main/scala/firrtl/ir/StructuralHash.scala
index f1ed91f3..20c63e4e 100644
--- a/src/main/scala/firrtl/ir/StructuralHash.scala
+++ b/src/main/scala/firrtl/ir/StructuralHash.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.ir
import firrtl.PrimOps
diff --git a/src/main/scala/firrtl/options/DependencyManager.scala b/src/main/scala/firrtl/options/DependencyManager.scala
index 561e32ab..39998ed7 100644
--- a/src/main/scala/firrtl/options/DependencyManager.scala
+++ b/src/main/scala/firrtl/options/DependencyManager.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.options
diff --git a/src/main/scala/firrtl/options/Exceptions.scala b/src/main/scala/firrtl/options/Exceptions.scala
index 3773e156..1b183d10 100644
--- a/src/main/scala/firrtl/options/Exceptions.scala
+++ b/src/main/scala/firrtl/options/Exceptions.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.options
diff --git a/src/main/scala/firrtl/options/ExitCodes.scala b/src/main/scala/firrtl/options/ExitCodes.scala
index 94e525de..79915e93 100644
--- a/src/main/scala/firrtl/options/ExitCodes.scala
+++ b/src/main/scala/firrtl/options/ExitCodes.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.options
diff --git a/src/main/scala/firrtl/options/OptionParser.scala b/src/main/scala/firrtl/options/OptionParser.scala
index e7ea68bf..79163aea 100644
--- a/src/main/scala/firrtl/options/OptionParser.scala
+++ b/src/main/scala/firrtl/options/OptionParser.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.options
diff --git a/src/main/scala/firrtl/options/OptionsView.scala b/src/main/scala/firrtl/options/OptionsView.scala
index 4235b660..01d2a4d4 100644
--- a/src/main/scala/firrtl/options/OptionsView.scala
+++ b/src/main/scala/firrtl/options/OptionsView.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.options
diff --git a/src/main/scala/firrtl/options/Phase.scala b/src/main/scala/firrtl/options/Phase.scala
index 6a3f4a8c..b836c386 100644
--- a/src/main/scala/firrtl/options/Phase.scala
+++ b/src/main/scala/firrtl/options/Phase.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.options
diff --git a/src/main/scala/firrtl/options/Registration.scala b/src/main/scala/firrtl/options/Registration.scala
index 55772c79..1ebccea4 100644
--- a/src/main/scala/firrtl/options/Registration.scala
+++ b/src/main/scala/firrtl/options/Registration.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.options
diff --git a/src/main/scala/firrtl/options/Shell.scala b/src/main/scala/firrtl/options/Shell.scala
index b0ead81f..f7b9371f 100644
--- a/src/main/scala/firrtl/options/Shell.scala
+++ b/src/main/scala/firrtl/options/Shell.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.options
diff --git a/src/main/scala/firrtl/options/Stage.scala b/src/main/scala/firrtl/options/Stage.scala
index 77c8133b..8e2c11d1 100644
--- a/src/main/scala/firrtl/options/Stage.scala
+++ b/src/main/scala/firrtl/options/Stage.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.options
diff --git a/src/main/scala/firrtl/options/StageAnnotations.scala b/src/main/scala/firrtl/options/StageAnnotations.scala
index e2835e16..2b12dd4e 100644
--- a/src/main/scala/firrtl/options/StageAnnotations.scala
+++ b/src/main/scala/firrtl/options/StageAnnotations.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details
+// SPDX-License-Identifier: Apache-2.0
package firrtl.options
diff --git a/src/main/scala/firrtl/options/StageOptions.scala b/src/main/scala/firrtl/options/StageOptions.scala
index 6b9190a7..3899fee1 100644
--- a/src/main/scala/firrtl/options/StageOptions.scala
+++ b/src/main/scala/firrtl/options/StageOptions.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.options
diff --git a/src/main/scala/firrtl/options/StageUtils.scala b/src/main/scala/firrtl/options/StageUtils.scala
index 2411da6e..c3867c7e 100644
--- a/src/main/scala/firrtl/options/StageUtils.scala
+++ b/src/main/scala/firrtl/options/StageUtils.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.options
diff --git a/src/main/scala/firrtl/options/package.scala b/src/main/scala/firrtl/options/package.scala
index f87fb8a8..7e826039 100644
--- a/src/main/scala/firrtl/options/package.scala
+++ b/src/main/scala/firrtl/options/package.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
diff --git a/src/main/scala/firrtl/options/phases/AddDefaults.scala b/src/main/scala/firrtl/options/phases/AddDefaults.scala
index 0ef1832a..dcd5b031 100644
--- a/src/main/scala/firrtl/options/phases/AddDefaults.scala
+++ b/src/main/scala/firrtl/options/phases/AddDefaults.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.options.phases
diff --git a/src/main/scala/firrtl/options/phases/Checks.scala b/src/main/scala/firrtl/options/phases/Checks.scala
index 024c13a9..64d81fb4 100644
--- a/src/main/scala/firrtl/options/phases/Checks.scala
+++ b/src/main/scala/firrtl/options/phases/Checks.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.options.phases
diff --git a/src/main/scala/firrtl/options/phases/ConvertLegacyAnnotations.scala b/src/main/scala/firrtl/options/phases/ConvertLegacyAnnotations.scala
index d75acbb2..8a363b58 100644
--- a/src/main/scala/firrtl/options/phases/ConvertLegacyAnnotations.scala
+++ b/src/main/scala/firrtl/options/phases/ConvertLegacyAnnotations.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.options.phases
diff --git a/src/main/scala/firrtl/options/phases/DeletedWrapper.scala b/src/main/scala/firrtl/options/phases/DeletedWrapper.scala
index 3661d836..fe2c6d78 100644
--- a/src/main/scala/firrtl/options/phases/DeletedWrapper.scala
+++ b/src/main/scala/firrtl/options/phases/DeletedWrapper.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.options.phases
diff --git a/src/main/scala/firrtl/options/phases/GetIncludes.scala b/src/main/scala/firrtl/options/phases/GetIncludes.scala
index dd08e09b..15692e79 100644
--- a/src/main/scala/firrtl/options/phases/GetIncludes.scala
+++ b/src/main/scala/firrtl/options/phases/GetIncludes.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.options.phases
diff --git a/src/main/scala/firrtl/options/phases/WriteOutputAnnotations.scala b/src/main/scala/firrtl/options/phases/WriteOutputAnnotations.scala
index e9a39c67..54f0951f 100644
--- a/src/main/scala/firrtl/options/phases/WriteOutputAnnotations.scala
+++ b/src/main/scala/firrtl/options/phases/WriteOutputAnnotations.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.options.phases
diff --git a/src/main/scala/firrtl/package.scala b/src/main/scala/firrtl/package.scala
index 11b2ab44..999b123d 100644
--- a/src/main/scala/firrtl/package.scala
+++ b/src/main/scala/firrtl/package.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
import firrtl.annotations.Annotation
diff --git a/src/main/scala/firrtl/passes/CInferMDir.scala b/src/main/scala/firrtl/passes/CInferMDir.scala
index 1fe8d57c..90f1c739 100644
--- a/src/main/scala/firrtl/passes/CInferMDir.scala
+++ b/src/main/scala/firrtl/passes/CInferMDir.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
diff --git a/src/main/scala/firrtl/passes/CheckChirrtl.scala b/src/main/scala/firrtl/passes/CheckChirrtl.scala
index 97d614c1..472de13b 100644
--- a/src/main/scala/firrtl/passes/CheckChirrtl.scala
+++ b/src/main/scala/firrtl/passes/CheckChirrtl.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
diff --git a/src/main/scala/firrtl/passes/CheckFlows.scala b/src/main/scala/firrtl/passes/CheckFlows.scala
index bc455a20..2816887f 100644
--- a/src/main/scala/firrtl/passes/CheckFlows.scala
+++ b/src/main/scala/firrtl/passes/CheckFlows.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
diff --git a/src/main/scala/firrtl/passes/CheckHighForm.scala b/src/main/scala/firrtl/passes/CheckHighForm.scala
index 559c9060..5514741a 100644
--- a/src/main/scala/firrtl/passes/CheckHighForm.scala
+++ b/src/main/scala/firrtl/passes/CheckHighForm.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
diff --git a/src/main/scala/firrtl/passes/CheckInitialization.scala b/src/main/scala/firrtl/passes/CheckInitialization.scala
index 96057831..896e21fc 100644
--- a/src/main/scala/firrtl/passes/CheckInitialization.scala
+++ b/src/main/scala/firrtl/passes/CheckInitialization.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
diff --git a/src/main/scala/firrtl/passes/CheckTypes.scala b/src/main/scala/firrtl/passes/CheckTypes.scala
index 956c1134..bbccb353 100644
--- a/src/main/scala/firrtl/passes/CheckTypes.scala
+++ b/src/main/scala/firrtl/passes/CheckTypes.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
diff --git a/src/main/scala/firrtl/passes/CheckWidths.scala b/src/main/scala/firrtl/passes/CheckWidths.scala
index f7fefa87..3f30e124 100644
--- a/src/main/scala/firrtl/passes/CheckWidths.scala
+++ b/src/main/scala/firrtl/passes/CheckWidths.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
diff --git a/src/main/scala/firrtl/passes/CommonSubexpressionElimination.scala b/src/main/scala/firrtl/passes/CommonSubexpressionElimination.scala
index 55a9c53a..e70346d4 100644
--- a/src/main/scala/firrtl/passes/CommonSubexpressionElimination.scala
+++ b/src/main/scala/firrtl/passes/CommonSubexpressionElimination.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
diff --git a/src/main/scala/firrtl/passes/ConvertFixedToSInt.scala b/src/main/scala/firrtl/passes/ConvertFixedToSInt.scala
index baf7d4d5..869cac3a 100644
--- a/src/main/scala/firrtl/passes/ConvertFixedToSInt.scala
+++ b/src/main/scala/firrtl/passes/ConvertFixedToSInt.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
diff --git a/src/main/scala/firrtl/passes/ExpandConnects.scala b/src/main/scala/firrtl/passes/ExpandConnects.scala
index 4f849c5a..518068a1 100644
--- a/src/main/scala/firrtl/passes/ExpandConnects.scala
+++ b/src/main/scala/firrtl/passes/ExpandConnects.scala
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0
+
package firrtl.passes
import firrtl.Utils.{create_exps, flow, get_field, get_valid_points, times, to_flip, to_flow}
diff --git a/src/main/scala/firrtl/passes/ExpandWhens.scala b/src/main/scala/firrtl/passes/ExpandWhens.scala
index 14d5d3ef..7456d2ab 100644
--- a/src/main/scala/firrtl/passes/ExpandWhens.scala
+++ b/src/main/scala/firrtl/passes/ExpandWhens.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
diff --git a/src/main/scala/firrtl/passes/InferBinaryPoints.scala b/src/main/scala/firrtl/passes/InferBinaryPoints.scala
index f393d8a5..8155462a 100644
--- a/src/main/scala/firrtl/passes/InferBinaryPoints.scala
+++ b/src/main/scala/firrtl/passes/InferBinaryPoints.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
diff --git a/src/main/scala/firrtl/passes/InferTypes.scala b/src/main/scala/firrtl/passes/InferTypes.scala
index 4d14e7ff..bbc1ef6d 100644
--- a/src/main/scala/firrtl/passes/InferTypes.scala
+++ b/src/main/scala/firrtl/passes/InferTypes.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
diff --git a/src/main/scala/firrtl/passes/InferWidths.scala b/src/main/scala/firrtl/passes/InferWidths.scala
index eae9690f..aa2095fa 100644
--- a/src/main/scala/firrtl/passes/InferWidths.scala
+++ b/src/main/scala/firrtl/passes/InferWidths.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
diff --git a/src/main/scala/firrtl/passes/Inline.scala b/src/main/scala/firrtl/passes/Inline.scala
index 00cda739..4eba5d59 100644
--- a/src/main/scala/firrtl/passes/Inline.scala
+++ b/src/main/scala/firrtl/passes/Inline.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
package passes
diff --git a/src/main/scala/firrtl/passes/Legalize.scala b/src/main/scala/firrtl/passes/Legalize.scala
index 5d59e075..ef0e1706 100644
--- a/src/main/scala/firrtl/passes/Legalize.scala
+++ b/src/main/scala/firrtl/passes/Legalize.scala
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0
+
package firrtl.passes
import firrtl.PrimOps._
diff --git a/src/main/scala/firrtl/passes/LowerTypes.scala b/src/main/scala/firrtl/passes/LowerTypes.scala
index ad608cec..592caf5d 100644
--- a/src/main/scala/firrtl/passes/LowerTypes.scala
+++ b/src/main/scala/firrtl/passes/LowerTypes.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
diff --git a/src/main/scala/firrtl/passes/PadWidths.scala b/src/main/scala/firrtl/passes/PadWidths.scala
index 79560605..875e80ae 100644
--- a/src/main/scala/firrtl/passes/PadWidths.scala
+++ b/src/main/scala/firrtl/passes/PadWidths.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
package passes
diff --git a/src/main/scala/firrtl/passes/Pass.scala b/src/main/scala/firrtl/passes/Pass.scala
index b5eac4ed..96b3b2ee 100644
--- a/src/main/scala/firrtl/passes/Pass.scala
+++ b/src/main/scala/firrtl/passes/Pass.scala
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0
+
package firrtl.passes
import firrtl.DependencyAPIMigration
diff --git a/src/main/scala/firrtl/passes/PullMuxes.scala b/src/main/scala/firrtl/passes/PullMuxes.scala
index 27543d63..ce9a8744 100644
--- a/src/main/scala/firrtl/passes/PullMuxes.scala
+++ b/src/main/scala/firrtl/passes/PullMuxes.scala
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0
+
package firrtl.passes
import firrtl.ir._
diff --git a/src/main/scala/firrtl/passes/RemoveAccesses.scala b/src/main/scala/firrtl/passes/RemoveAccesses.scala
index d8d32b26..f49af935 100644
--- a/src/main/scala/firrtl/passes/RemoveAccesses.scala
+++ b/src/main/scala/firrtl/passes/RemoveAccesses.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
diff --git a/src/main/scala/firrtl/passes/RemoveCHIRRTL.scala b/src/main/scala/firrtl/passes/RemoveCHIRRTL.scala
index 624138ab..f8511820 100644
--- a/src/main/scala/firrtl/passes/RemoveCHIRRTL.scala
+++ b/src/main/scala/firrtl/passes/RemoveCHIRRTL.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
diff --git a/src/main/scala/firrtl/passes/RemoveEmpty.scala b/src/main/scala/firrtl/passes/RemoveEmpty.scala
index eb25dcc4..a834b779 100644
--- a/src/main/scala/firrtl/passes/RemoveEmpty.scala
+++ b/src/main/scala/firrtl/passes/RemoveEmpty.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
package passes
diff --git a/src/main/scala/firrtl/passes/RemoveIntervals.scala b/src/main/scala/firrtl/passes/RemoveIntervals.scala
index 657b4356..3daec671 100644
--- a/src/main/scala/firrtl/passes/RemoveIntervals.scala
+++ b/src/main/scala/firrtl/passes/RemoveIntervals.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
diff --git a/src/main/scala/firrtl/passes/RemoveValidIf.scala b/src/main/scala/firrtl/passes/RemoveValidIf.scala
index 7e82b37b..bc8e8c1b 100644
--- a/src/main/scala/firrtl/passes/RemoveValidIf.scala
+++ b/src/main/scala/firrtl/passes/RemoveValidIf.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
package passes
diff --git a/src/main/scala/firrtl/passes/ReplaceAccesses.scala b/src/main/scala/firrtl/passes/ReplaceAccesses.scala
index 4a3cd697..ab48c3db 100644
--- a/src/main/scala/firrtl/passes/ReplaceAccesses.scala
+++ b/src/main/scala/firrtl/passes/ReplaceAccesses.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
diff --git a/src/main/scala/firrtl/passes/ResolveFlows.scala b/src/main/scala/firrtl/passes/ResolveFlows.scala
index 48b9479c..1af87c10 100644
--- a/src/main/scala/firrtl/passes/ResolveFlows.scala
+++ b/src/main/scala/firrtl/passes/ResolveFlows.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
diff --git a/src/main/scala/firrtl/passes/ResolveKinds.scala b/src/main/scala/firrtl/passes/ResolveKinds.scala
index fcbac163..25be003d 100644
--- a/src/main/scala/firrtl/passes/ResolveKinds.scala
+++ b/src/main/scala/firrtl/passes/ResolveKinds.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
diff --git a/src/main/scala/firrtl/passes/SplitExpressions.scala b/src/main/scala/firrtl/passes/SplitExpressions.scala
index a65f8921..1b4ed1cc 100644
--- a/src/main/scala/firrtl/passes/SplitExpressions.scala
+++ b/src/main/scala/firrtl/passes/SplitExpressions.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
package passes
diff --git a/src/main/scala/firrtl/passes/ToWorkingIR.scala b/src/main/scala/firrtl/passes/ToWorkingIR.scala
index 03faaf3c..2a814497 100644
--- a/src/main/scala/firrtl/passes/ToWorkingIR.scala
+++ b/src/main/scala/firrtl/passes/ToWorkingIR.scala
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0
+
package firrtl.passes
import firrtl.ir._
diff --git a/src/main/scala/firrtl/passes/TrimIntervals.scala b/src/main/scala/firrtl/passes/TrimIntervals.scala
index 0a05bd4e..99a97a38 100644
--- a/src/main/scala/firrtl/passes/TrimIntervals.scala
+++ b/src/main/scala/firrtl/passes/TrimIntervals.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
diff --git a/src/main/scala/firrtl/passes/Uniquify.scala b/src/main/scala/firrtl/passes/Uniquify.scala
index 57ef11fa..81916282 100644
--- a/src/main/scala/firrtl/passes/Uniquify.scala
+++ b/src/main/scala/firrtl/passes/Uniquify.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
diff --git a/src/main/scala/firrtl/passes/VerilogModulusCleanup.scala b/src/main/scala/firrtl/passes/VerilogModulusCleanup.scala
index 0b046a5f..baad2f4f 100644
--- a/src/main/scala/firrtl/passes/VerilogModulusCleanup.scala
+++ b/src/main/scala/firrtl/passes/VerilogModulusCleanup.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
package passes
diff --git a/src/main/scala/firrtl/passes/VerilogPrep.scala b/src/main/scala/firrtl/passes/VerilogPrep.scala
index eeb34fa9..ed5db92e 100644
--- a/src/main/scala/firrtl/passes/VerilogPrep.scala
+++ b/src/main/scala/firrtl/passes/VerilogPrep.scala
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0
+
package firrtl.passes
import firrtl.Utils.{create_exps, flow, kind, toWrappedExpression}
diff --git a/src/main/scala/firrtl/passes/ZeroLengthVecs.scala b/src/main/scala/firrtl/passes/ZeroLengthVecs.scala
index e61780a4..0c8e0fa7 100644
--- a/src/main/scala/firrtl/passes/ZeroLengthVecs.scala
+++ b/src/main/scala/firrtl/passes/ZeroLengthVecs.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
diff --git a/src/main/scala/firrtl/passes/ZeroWidth.scala b/src/main/scala/firrtl/passes/ZeroWidth.scala
index 82321f95..60439ec1 100644
--- a/src/main/scala/firrtl/passes/ZeroWidth.scala
+++ b/src/main/scala/firrtl/passes/ZeroWidth.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
diff --git a/src/main/scala/firrtl/passes/clocklist/ClockList.scala b/src/main/scala/firrtl/passes/clocklist/ClockList.scala
index bfc03b51..f4ddbf21 100644
--- a/src/main/scala/firrtl/passes/clocklist/ClockList.scala
+++ b/src/main/scala/firrtl/passes/clocklist/ClockList.scala
@@ -1,4 +1,4 @@
-// See license file for details
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
package clocklist
diff --git a/src/main/scala/firrtl/passes/clocklist/ClockListTransform.scala b/src/main/scala/firrtl/passes/clocklist/ClockListTransform.scala
index 468ba905..a4461118 100644
--- a/src/main/scala/firrtl/passes/clocklist/ClockListTransform.scala
+++ b/src/main/scala/firrtl/passes/clocklist/ClockListTransform.scala
@@ -1,4 +1,4 @@
-// See license file for details
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
package clocklist
diff --git a/src/main/scala/firrtl/passes/clocklist/ClockListUtils.scala b/src/main/scala/firrtl/passes/clocklist/ClockListUtils.scala
index 00e07588..9e0a202b 100644
--- a/src/main/scala/firrtl/passes/clocklist/ClockListUtils.scala
+++ b/src/main/scala/firrtl/passes/clocklist/ClockListUtils.scala
@@ -1,4 +1,4 @@
-// See license file for details
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
package clocklist
diff --git a/src/main/scala/firrtl/passes/clocklist/RemoveAllButClocks.scala b/src/main/scala/firrtl/passes/clocklist/RemoveAllButClocks.scala
index d72bc293..9ad653cf 100644
--- a/src/main/scala/firrtl/passes/clocklist/RemoveAllButClocks.scala
+++ b/src/main/scala/firrtl/passes/clocklist/RemoveAllButClocks.scala
@@ -1,4 +1,4 @@
-// See license file for details
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
package clocklist
diff --git a/src/main/scala/firrtl/passes/memlib/DecorateMems.scala b/src/main/scala/firrtl/passes/memlib/DecorateMems.scala
index d237c36a..1cdecdfa 100644
--- a/src/main/scala/firrtl/passes/memlib/DecorateMems.scala
+++ b/src/main/scala/firrtl/passes/memlib/DecorateMems.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
package passes
diff --git a/src/main/scala/firrtl/passes/memlib/InferReadWrite.scala b/src/main/scala/firrtl/passes/memlib/InferReadWrite.scala
index e290633e..0bb94452 100644
--- a/src/main/scala/firrtl/passes/memlib/InferReadWrite.scala
+++ b/src/main/scala/firrtl/passes/memlib/InferReadWrite.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
package memlib
diff --git a/src/main/scala/firrtl/passes/memlib/MemConf.scala b/src/main/scala/firrtl/passes/memlib/MemConf.scala
index 871a1093..637b57e0 100644
--- a/src/main/scala/firrtl/passes/memlib/MemConf.scala
+++ b/src/main/scala/firrtl/passes/memlib/MemConf.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
package memlib
diff --git a/src/main/scala/firrtl/passes/memlib/MemIR.scala b/src/main/scala/firrtl/passes/memlib/MemIR.scala
index c8cd3e8d..881aefed 100644
--- a/src/main/scala/firrtl/passes/memlib/MemIR.scala
+++ b/src/main/scala/firrtl/passes/memlib/MemIR.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
package memlib
diff --git a/src/main/scala/firrtl/passes/memlib/MemLibOptions.scala b/src/main/scala/firrtl/passes/memlib/MemLibOptions.scala
index 1db132f7..186ca78c 100644
--- a/src/main/scala/firrtl/passes/memlib/MemLibOptions.scala
+++ b/src/main/scala/firrtl/passes/memlib/MemLibOptions.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes.memlib
diff --git a/src/main/scala/firrtl/passes/memlib/MemTransformUtils.scala b/src/main/scala/firrtl/passes/memlib/MemTransformUtils.scala
index f153fa2b..429ce19f 100644
--- a/src/main/scala/firrtl/passes/memlib/MemTransformUtils.scala
+++ b/src/main/scala/firrtl/passes/memlib/MemTransformUtils.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
package memlib
diff --git a/src/main/scala/firrtl/passes/memlib/MemUtils.scala b/src/main/scala/firrtl/passes/memlib/MemUtils.scala
index f325c0ba..a5bb26a0 100644
--- a/src/main/scala/firrtl/passes/memlib/MemUtils.scala
+++ b/src/main/scala/firrtl/passes/memlib/MemUtils.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
diff --git a/src/main/scala/firrtl/passes/memlib/RenameAnnotatedMemoryPorts.scala b/src/main/scala/firrtl/passes/memlib/RenameAnnotatedMemoryPorts.scala
index 30529119..43a46bf1 100644
--- a/src/main/scala/firrtl/passes/memlib/RenameAnnotatedMemoryPorts.scala
+++ b/src/main/scala/firrtl/passes/memlib/RenameAnnotatedMemoryPorts.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
package memlib
diff --git a/src/main/scala/firrtl/passes/memlib/ReplaceMemMacros.scala b/src/main/scala/firrtl/passes/memlib/ReplaceMemMacros.scala
index fc381e88..63ae0490 100644
--- a/src/main/scala/firrtl/passes/memlib/ReplaceMemMacros.scala
+++ b/src/main/scala/firrtl/passes/memlib/ReplaceMemMacros.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
package memlib
diff --git a/src/main/scala/firrtl/passes/memlib/ReplaceMemTransform.scala b/src/main/scala/firrtl/passes/memlib/ReplaceMemTransform.scala
index c88d6ba7..f0325e8e 100644
--- a/src/main/scala/firrtl/passes/memlib/ReplaceMemTransform.scala
+++ b/src/main/scala/firrtl/passes/memlib/ReplaceMemTransform.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
package memlib
diff --git a/src/main/scala/firrtl/passes/memlib/ResolveMaskGranularity.scala b/src/main/scala/firrtl/passes/memlib/ResolveMaskGranularity.scala
index 434c7602..7a1a57fb 100644
--- a/src/main/scala/firrtl/passes/memlib/ResolveMaskGranularity.scala
+++ b/src/main/scala/firrtl/passes/memlib/ResolveMaskGranularity.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
package memlib
diff --git a/src/main/scala/firrtl/passes/memlib/ResolveMemoryReference.scala b/src/main/scala/firrtl/passes/memlib/ResolveMemoryReference.scala
index e80e0c4a..73aa5399 100644
--- a/src/main/scala/firrtl/passes/memlib/ResolveMemoryReference.scala
+++ b/src/main/scala/firrtl/passes/memlib/ResolveMemoryReference.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
package memlib
diff --git a/src/main/scala/firrtl/passes/memlib/ToMemIR.scala b/src/main/scala/firrtl/passes/memlib/ToMemIR.scala
index 9fe7f852..d17f0d59 100644
--- a/src/main/scala/firrtl/passes/memlib/ToMemIR.scala
+++ b/src/main/scala/firrtl/passes/memlib/ToMemIR.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
package memlib
diff --git a/src/main/scala/firrtl/passes/memlib/VerilogMemDelays.scala b/src/main/scala/firrtl/passes/memlib/VerilogMemDelays.scala
index a2b14343..1cecf543 100644
--- a/src/main/scala/firrtl/passes/memlib/VerilogMemDelays.scala
+++ b/src/main/scala/firrtl/passes/memlib/VerilogMemDelays.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
package memlib
diff --git a/src/main/scala/firrtl/passes/memlib/YamlUtils.scala b/src/main/scala/firrtl/passes/memlib/YamlUtils.scala
index b5f91e7b..99344973 100644
--- a/src/main/scala/firrtl/passes/memlib/YamlUtils.scala
+++ b/src/main/scala/firrtl/passes/memlib/YamlUtils.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
package memlib
diff --git a/src/main/scala/firrtl/passes/wiring/Wiring.scala b/src/main/scala/firrtl/passes/wiring/Wiring.scala
index a69b7797..45eb61bf 100644
--- a/src/main/scala/firrtl/passes/wiring/Wiring.scala
+++ b/src/main/scala/firrtl/passes/wiring/Wiring.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
package wiring
diff --git a/src/main/scala/firrtl/passes/wiring/WiringTransform.scala b/src/main/scala/firrtl/passes/wiring/WiringTransform.scala
index d6658f16..4f6705ec 100644
--- a/src/main/scala/firrtl/passes/wiring/WiringTransform.scala
+++ b/src/main/scala/firrtl/passes/wiring/WiringTransform.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
package wiring
diff --git a/src/main/scala/firrtl/passes/wiring/WiringUtils.scala b/src/main/scala/firrtl/passes/wiring/WiringUtils.scala
index 59b042f5..0b121cc0 100644
--- a/src/main/scala/firrtl/passes/wiring/WiringUtils.scala
+++ b/src/main/scala/firrtl/passes/wiring/WiringUtils.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.passes
package wiring
diff --git a/src/main/scala/firrtl/proto/FromProto.scala b/src/main/scala/firrtl/proto/FromProto.scala
index 5b9dd371..663e91b3 100644
--- a/src/main/scala/firrtl/proto/FromProto.scala
+++ b/src/main/scala/firrtl/proto/FromProto.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
package proto
diff --git a/src/main/scala/firrtl/proto/ToProto.scala b/src/main/scala/firrtl/proto/ToProto.scala
index 78b95582..4cdf6b85 100644
--- a/src/main/scala/firrtl/proto/ToProto.scala
+++ b/src/main/scala/firrtl/proto/ToProto.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
package proto
diff --git a/src/main/scala/firrtl/stage/FirrtlAnnotations.scala b/src/main/scala/firrtl/stage/FirrtlAnnotations.scala
index 56072cb4..99a6e9c3 100644
--- a/src/main/scala/firrtl/stage/FirrtlAnnotations.scala
+++ b/src/main/scala/firrtl/stage/FirrtlAnnotations.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details
+// SPDX-License-Identifier: Apache-2.0
package firrtl.stage
diff --git a/src/main/scala/firrtl/stage/FirrtlCli.scala b/src/main/scala/firrtl/stage/FirrtlCli.scala
index 450248ea..18f14107 100644
--- a/src/main/scala/firrtl/stage/FirrtlCli.scala
+++ b/src/main/scala/firrtl/stage/FirrtlCli.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.stage
diff --git a/src/main/scala/firrtl/stage/FirrtlOptions.scala b/src/main/scala/firrtl/stage/FirrtlOptions.scala
index 55d4cc31..64fa569c 100644
--- a/src/main/scala/firrtl/stage/FirrtlOptions.scala
+++ b/src/main/scala/firrtl/stage/FirrtlOptions.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.stage
diff --git a/src/main/scala/firrtl/stage/FirrtlStage.scala b/src/main/scala/firrtl/stage/FirrtlStage.scala
index b92fc4ef..0b1e6578 100644
--- a/src/main/scala/firrtl/stage/FirrtlStage.scala
+++ b/src/main/scala/firrtl/stage/FirrtlStage.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.stage
diff --git a/src/main/scala/firrtl/stage/FirrtlStageUtils.scala b/src/main/scala/firrtl/stage/FirrtlStageUtils.scala
index aa9781db..6a34ddcf 100644
--- a/src/main/scala/firrtl/stage/FirrtlStageUtils.scala
+++ b/src/main/scala/firrtl/stage/FirrtlStageUtils.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.stage
diff --git a/src/main/scala/firrtl/stage/Forms.scala b/src/main/scala/firrtl/stage/Forms.scala
index db411325..a6077f52 100644
--- a/src/main/scala/firrtl/stage/Forms.scala
+++ b/src/main/scala/firrtl/stage/Forms.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.stage
diff --git a/src/main/scala/firrtl/stage/TransformManager.scala b/src/main/scala/firrtl/stage/TransformManager.scala
index aa96ca86..3029ddb5 100644
--- a/src/main/scala/firrtl/stage/TransformManager.scala
+++ b/src/main/scala/firrtl/stage/TransformManager.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.stage
diff --git a/src/main/scala/firrtl/stage/package.scala b/src/main/scala/firrtl/stage/package.scala
index 21182c84..c159f852 100644
--- a/src/main/scala/firrtl/stage/package.scala
+++ b/src/main/scala/firrtl/stage/package.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
diff --git a/src/main/scala/firrtl/stage/phases/AddCircuit.scala b/src/main/scala/firrtl/stage/phases/AddCircuit.scala
index c00e71b6..1401560c 100644
--- a/src/main/scala/firrtl/stage/phases/AddCircuit.scala
+++ b/src/main/scala/firrtl/stage/phases/AddCircuit.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.stage.phases
diff --git a/src/main/scala/firrtl/stage/phases/AddDefaults.scala b/src/main/scala/firrtl/stage/phases/AddDefaults.scala
index b296b59d..63de1a7b 100644
--- a/src/main/scala/firrtl/stage/phases/AddDefaults.scala
+++ b/src/main/scala/firrtl/stage/phases/AddDefaults.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.stage.phases
diff --git a/src/main/scala/firrtl/stage/phases/AddImplicitEmitter.scala b/src/main/scala/firrtl/stage/phases/AddImplicitEmitter.scala
index 3c0a2388..a252f4f3 100644
--- a/src/main/scala/firrtl/stage/phases/AddImplicitEmitter.scala
+++ b/src/main/scala/firrtl/stage/phases/AddImplicitEmitter.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.stage.phases
diff --git a/src/main/scala/firrtl/stage/phases/AddImplicitOutputFile.scala b/src/main/scala/firrtl/stage/phases/AddImplicitOutputFile.scala
index 10af13d5..dcc2be4f 100644
--- a/src/main/scala/firrtl/stage/phases/AddImplicitOutputFile.scala
+++ b/src/main/scala/firrtl/stage/phases/AddImplicitOutputFile.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.stage.phases
diff --git a/src/main/scala/firrtl/stage/phases/CatchExceptions.scala b/src/main/scala/firrtl/stage/phases/CatchExceptions.scala
index 5181653b..c3b304a5 100644
--- a/src/main/scala/firrtl/stage/phases/CatchExceptions.scala
+++ b/src/main/scala/firrtl/stage/phases/CatchExceptions.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.stage.phases
diff --git a/src/main/scala/firrtl/stage/phases/Checks.scala b/src/main/scala/firrtl/stage/phases/Checks.scala
index 44828ae6..e9065393 100644
--- a/src/main/scala/firrtl/stage/phases/Checks.scala
+++ b/src/main/scala/firrtl/stage/phases/Checks.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.stage.phases
diff --git a/src/main/scala/firrtl/stage/phases/Compiler.scala b/src/main/scala/firrtl/stage/phases/Compiler.scala
index 0d1181a6..24848f36 100644
--- a/src/main/scala/firrtl/stage/phases/Compiler.scala
+++ b/src/main/scala/firrtl/stage/phases/Compiler.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.stage.phases
diff --git a/src/main/scala/firrtl/stage/phases/ConvertCompilerAnnotations.scala b/src/main/scala/firrtl/stage/phases/ConvertCompilerAnnotations.scala
index b4743cde..edd38dc6 100644
--- a/src/main/scala/firrtl/stage/phases/ConvertCompilerAnnotations.scala
+++ b/src/main/scala/firrtl/stage/phases/ConvertCompilerAnnotations.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.stage.phases
diff --git a/src/main/scala/firrtl/stage/phases/DriverCompatibility.scala b/src/main/scala/firrtl/stage/phases/DriverCompatibility.scala
index 529f9ca3..a37774e5 100644
--- a/src/main/scala/firrtl/stage/phases/DriverCompatibility.scala
+++ b/src/main/scala/firrtl/stage/phases/DriverCompatibility.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.stage.phases
diff --git a/src/main/scala/firrtl/stage/phases/WriteEmitted.scala b/src/main/scala/firrtl/stage/phases/WriteEmitted.scala
index 614ce62f..010e85c3 100644
--- a/src/main/scala/firrtl/stage/phases/WriteEmitted.scala
+++ b/src/main/scala/firrtl/stage/phases/WriteEmitted.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.stage.phases
diff --git a/src/main/scala/firrtl/stage/transforms/CatchCustomTransformExceptions.scala b/src/main/scala/firrtl/stage/transforms/CatchCustomTransformExceptions.scala
index 742d2b7e..6e50224a 100644
--- a/src/main/scala/firrtl/stage/transforms/CatchCustomTransformExceptions.scala
+++ b/src/main/scala/firrtl/stage/transforms/CatchCustomTransformExceptions.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.stage.transforms
diff --git a/src/main/scala/firrtl/stage/transforms/CheckScalaVersion.scala b/src/main/scala/firrtl/stage/transforms/CheckScalaVersion.scala
index 65dfd89a..9d894905 100644
--- a/src/main/scala/firrtl/stage/transforms/CheckScalaVersion.scala
+++ b/src/main/scala/firrtl/stage/transforms/CheckScalaVersion.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.stage.transforms
diff --git a/src/main/scala/firrtl/stage/transforms/Compiler.scala b/src/main/scala/firrtl/stage/transforms/Compiler.scala
index 251f4387..42e933bd 100644
--- a/src/main/scala/firrtl/stage/transforms/Compiler.scala
+++ b/src/main/scala/firrtl/stage/transforms/Compiler.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.stage.transforms
diff --git a/src/main/scala/firrtl/stage/transforms/ExpandPrepares.scala b/src/main/scala/firrtl/stage/transforms/ExpandPrepares.scala
index d0514f15..273c0bdc 100644
--- a/src/main/scala/firrtl/stage/transforms/ExpandPrepares.scala
+++ b/src/main/scala/firrtl/stage/transforms/ExpandPrepares.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.stage.transforms
diff --git a/src/main/scala/firrtl/stage/transforms/TrackTransforms.scala b/src/main/scala/firrtl/stage/transforms/TrackTransforms.scala
index c268332a..62363a77 100644
--- a/src/main/scala/firrtl/stage/transforms/TrackTransforms.scala
+++ b/src/main/scala/firrtl/stage/transforms/TrackTransforms.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.stage.transforms
diff --git a/src/main/scala/firrtl/stage/transforms/UpdateAnnotations.scala b/src/main/scala/firrtl/stage/transforms/UpdateAnnotations.scala
index e36eef9b..4fa7788d 100644
--- a/src/main/scala/firrtl/stage/transforms/UpdateAnnotations.scala
+++ b/src/main/scala/firrtl/stage/transforms/UpdateAnnotations.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.stage.transforms
diff --git a/src/main/scala/firrtl/stage/transforms/WrappedTransform.scala b/src/main/scala/firrtl/stage/transforms/WrappedTransform.scala
index 2b49e0eb..3e81977c 100644
--- a/src/main/scala/firrtl/stage/transforms/WrappedTransform.scala
+++ b/src/main/scala/firrtl/stage/transforms/WrappedTransform.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.stage.transforms
diff --git a/src/main/scala/firrtl/transforms/BlackBoxSourceHelper.scala b/src/main/scala/firrtl/transforms/BlackBoxSourceHelper.scala
index 5000e07a..12f33183 100644
--- a/src/main/scala/firrtl/transforms/BlackBoxSourceHelper.scala
+++ b/src/main/scala/firrtl/transforms/BlackBoxSourceHelper.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.transforms
diff --git a/src/main/scala/firrtl/transforms/CheckCombLoops.scala b/src/main/scala/firrtl/transforms/CheckCombLoops.scala
index ee4c1d0b..dee2f9c8 100644
--- a/src/main/scala/firrtl/transforms/CheckCombLoops.scala
+++ b/src/main/scala/firrtl/transforms/CheckCombLoops.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.transforms
diff --git a/src/main/scala/firrtl/transforms/CombineCats.scala b/src/main/scala/firrtl/transforms/CombineCats.scala
index 6d05698f..a37e6f08 100644
--- a/src/main/scala/firrtl/transforms/CombineCats.scala
+++ b/src/main/scala/firrtl/transforms/CombineCats.scala
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0
+
package firrtl
package transforms
diff --git a/src/main/scala/firrtl/transforms/ConstantPropagation.scala b/src/main/scala/firrtl/transforms/ConstantPropagation.scala
index 10e99beb..5d57de3a 100644
--- a/src/main/scala/firrtl/transforms/ConstantPropagation.scala
+++ b/src/main/scala/firrtl/transforms/ConstantPropagation.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
package transforms
diff --git a/src/main/scala/firrtl/transforms/DeadCodeElimination.scala b/src/main/scala/firrtl/transforms/DeadCodeElimination.scala
index c9b42f8e..13173fdd 100644
--- a/src/main/scala/firrtl/transforms/DeadCodeElimination.scala
+++ b/src/main/scala/firrtl/transforms/DeadCodeElimination.scala
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0
+
package firrtl.transforms
import firrtl._
diff --git a/src/main/scala/firrtl/transforms/Dedup.scala b/src/main/scala/firrtl/transforms/Dedup.scala
index 18e32cbc..2fb98224 100644
--- a/src/main/scala/firrtl/transforms/Dedup.scala
+++ b/src/main/scala/firrtl/transforms/Dedup.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
package transforms
diff --git a/src/main/scala/firrtl/transforms/FixAddingNegativeLiteralsTransform.scala b/src/main/scala/firrtl/transforms/FixAddingNegativeLiteralsTransform.scala
index bfab31bf..2ba28ebb 100644
--- a/src/main/scala/firrtl/transforms/FixAddingNegativeLiteralsTransform.scala
+++ b/src/main/scala/firrtl/transforms/FixAddingNegativeLiteralsTransform.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.transforms
diff --git a/src/main/scala/firrtl/transforms/Flatten.scala b/src/main/scala/firrtl/transforms/Flatten.scala
index 36e71470..1d9f8083 100644
--- a/src/main/scala/firrtl/transforms/Flatten.scala
+++ b/src/main/scala/firrtl/transforms/Flatten.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
package transforms
diff --git a/src/main/scala/firrtl/transforms/FlattenRegUpdate.scala b/src/main/scala/firrtl/transforms/FlattenRegUpdate.scala
index b582fe2a..664ce1e6 100644
--- a/src/main/scala/firrtl/transforms/FlattenRegUpdate.scala
+++ b/src/main/scala/firrtl/transforms/FlattenRegUpdate.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
package transforms
diff --git a/src/main/scala/firrtl/transforms/GroupComponents.scala b/src/main/scala/firrtl/transforms/GroupComponents.scala
index 0db67f1e..ae110414 100644
--- a/src/main/scala/firrtl/transforms/GroupComponents.scala
+++ b/src/main/scala/firrtl/transforms/GroupComponents.scala
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0
+
package firrtl.transforms
import firrtl._
diff --git a/src/main/scala/firrtl/transforms/IdentityTransform.scala b/src/main/scala/firrtl/transforms/IdentityTransform.scala
index 4faa5cd0..16da324e 100644
--- a/src/main/scala/firrtl/transforms/IdentityTransform.scala
+++ b/src/main/scala/firrtl/transforms/IdentityTransform.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.transforms
diff --git a/src/main/scala/firrtl/transforms/InferResets.scala b/src/main/scala/firrtl/transforms/InferResets.scala
index 376382cc..0f5fb608 100644
--- a/src/main/scala/firrtl/transforms/InferResets.scala
+++ b/src/main/scala/firrtl/transforms/InferResets.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.transforms
diff --git a/src/main/scala/firrtl/transforms/InlineBitExtractions.scala b/src/main/scala/firrtl/transforms/InlineBitExtractions.scala
index 100b598f..4b2773c5 100644
--- a/src/main/scala/firrtl/transforms/InlineBitExtractions.scala
+++ b/src/main/scala/firrtl/transforms/InlineBitExtractions.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
package transforms
diff --git a/src/main/scala/firrtl/transforms/InlineBooleanExpressions.scala b/src/main/scala/firrtl/transforms/InlineBooleanExpressions.scala
index 29bdde0f..fcf8e335 100644
--- a/src/main/scala/firrtl/transforms/InlineBooleanExpressions.scala
+++ b/src/main/scala/firrtl/transforms/InlineBooleanExpressions.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
package transforms
diff --git a/src/main/scala/firrtl/transforms/InlineCasts.scala b/src/main/scala/firrtl/transforms/InlineCasts.scala
index 0efc0727..71318eee 100644
--- a/src/main/scala/firrtl/transforms/InlineCasts.scala
+++ b/src/main/scala/firrtl/transforms/InlineCasts.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
package transforms
diff --git a/src/main/scala/firrtl/transforms/LegalizeClocksAndAsyncResets.scala b/src/main/scala/firrtl/transforms/LegalizeClocksAndAsyncResets.scala
index 0edf0cc6..5e3d276d 100644
--- a/src/main/scala/firrtl/transforms/LegalizeClocksAndAsyncResets.scala
+++ b/src/main/scala/firrtl/transforms/LegalizeClocksAndAsyncResets.scala
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0
+
package firrtl
package transforms
diff --git a/src/main/scala/firrtl/transforms/LegalizeReductions.scala b/src/main/scala/firrtl/transforms/LegalizeReductions.scala
index 33a10349..b5751b14 100644
--- a/src/main/scala/firrtl/transforms/LegalizeReductions.scala
+++ b/src/main/scala/firrtl/transforms/LegalizeReductions.scala
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0
+
package firrtl
package transforms
diff --git a/src/main/scala/firrtl/transforms/ManipulateNames.scala b/src/main/scala/firrtl/transforms/ManipulateNames.scala
index d0b12e66..1dbc46ad 100644
--- a/src/main/scala/firrtl/transforms/ManipulateNames.scala
+++ b/src/main/scala/firrtl/transforms/ManipulateNames.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.transforms
diff --git a/src/main/scala/firrtl/transforms/OptimizationAnnotations.scala b/src/main/scala/firrtl/transforms/OptimizationAnnotations.scala
index 5532d0f0..10163b72 100644
--- a/src/main/scala/firrtl/transforms/OptimizationAnnotations.scala
+++ b/src/main/scala/firrtl/transforms/OptimizationAnnotations.scala
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0
+
package firrtl
package transforms
diff --git a/src/main/scala/firrtl/transforms/PropagatePresetAnnotations.scala b/src/main/scala/firrtl/transforms/PropagatePresetAnnotations.scala
index 97db0219..941dce41 100644
--- a/src/main/scala/firrtl/transforms/PropagatePresetAnnotations.scala
+++ b/src/main/scala/firrtl/transforms/PropagatePresetAnnotations.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
package transforms
diff --git a/src/main/scala/firrtl/transforms/RemoveKeywordCollisions.scala b/src/main/scala/firrtl/transforms/RemoveKeywordCollisions.scala
index 216dd7c1..3cf0e40a 100644
--- a/src/main/scala/firrtl/transforms/RemoveKeywordCollisions.scala
+++ b/src/main/scala/firrtl/transforms/RemoveKeywordCollisions.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.transforms
diff --git a/src/main/scala/firrtl/transforms/RemoveReset.scala b/src/main/scala/firrtl/transforms/RemoveReset.scala
index 8736e21b..14880ab9 100644
--- a/src/main/scala/firrtl/transforms/RemoveReset.scala
+++ b/src/main/scala/firrtl/transforms/RemoveReset.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
package transforms
diff --git a/src/main/scala/firrtl/transforms/RemoveWires.scala b/src/main/scala/firrtl/transforms/RemoveWires.scala
index 31fa3b6f..440989f4 100644
--- a/src/main/scala/firrtl/transforms/RemoveWires.scala
+++ b/src/main/scala/firrtl/transforms/RemoveWires.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
package transforms
diff --git a/src/main/scala/firrtl/transforms/RenameModules.scala b/src/main/scala/firrtl/transforms/RenameModules.scala
index 16fd655a..162f726e 100644
--- a/src/main/scala/firrtl/transforms/RenameModules.scala
+++ b/src/main/scala/firrtl/transforms/RenameModules.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.transforms
diff --git a/src/main/scala/firrtl/transforms/ReplaceTruncatingArithmetic.scala b/src/main/scala/firrtl/transforms/ReplaceTruncatingArithmetic.scala
index 14c84b91..b34b1f6a 100644
--- a/src/main/scala/firrtl/transforms/ReplaceTruncatingArithmetic.scala
+++ b/src/main/scala/firrtl/transforms/ReplaceTruncatingArithmetic.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
package transforms
diff --git a/src/main/scala/firrtl/transforms/SimplifyMems.scala b/src/main/scala/firrtl/transforms/SimplifyMems.scala
index 7790d060..8ecc484a 100644
--- a/src/main/scala/firrtl/transforms/SimplifyMems.scala
+++ b/src/main/scala/firrtl/transforms/SimplifyMems.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl
package transforms
diff --git a/src/main/scala/firrtl/transforms/TopWiring.scala b/src/main/scala/firrtl/transforms/TopWiring.scala
index b35fed22..c231d347 100644
--- a/src/main/scala/firrtl/transforms/TopWiring.scala
+++ b/src/main/scala/firrtl/transforms/TopWiring.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.transforms
package TopWiring
diff --git a/src/main/scala/firrtl/transforms/formal/AssertSubmoduleAssumptions.scala b/src/main/scala/firrtl/transforms/formal/AssertSubmoduleAssumptions.scala
index cdbee495..e5e65d1d 100644
--- a/src/main/scala/firrtl/transforms/formal/AssertSubmoduleAssumptions.scala
+++ b/src/main/scala/firrtl/transforms/formal/AssertSubmoduleAssumptions.scala
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0
+
package firrtl.transforms.formal
import firrtl.ir.{Circuit, Formal, Statement, Verification}
diff --git a/src/main/scala/firrtl/transforms/formal/ConvertAsserts.scala b/src/main/scala/firrtl/transforms/formal/ConvertAsserts.scala
index 5928c79c..e49be6eb 100644
--- a/src/main/scala/firrtl/transforms/formal/ConvertAsserts.scala
+++ b/src/main/scala/firrtl/transforms/formal/ConvertAsserts.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.transforms.formal
diff --git a/src/main/scala/firrtl/transforms/formal/RemoveVerificationStatements.scala b/src/main/scala/firrtl/transforms/formal/RemoveVerificationStatements.scala
index 1e6d2c72..35e2d804 100644
--- a/src/main/scala/firrtl/transforms/formal/RemoveVerificationStatements.scala
+++ b/src/main/scala/firrtl/transforms/formal/RemoveVerificationStatements.scala
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0
+
package firrtl.transforms.formal
import firrtl.ir.{Circuit, EmptyStmt, Statement, Verification}
diff --git a/src/main/scala/firrtl/transforms/package.scala b/src/main/scala/firrtl/transforms/package.scala
index 4043598c..d758fa0a 100644
--- a/src/main/scala/firrtl/transforms/package.scala
+++ b/src/main/scala/firrtl/transforms/package.scala
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0
+
package firrtl
package object transforms {
diff --git a/src/main/scala/firrtl/traversals/Foreachers.scala b/src/main/scala/firrtl/traversals/Foreachers.scala
index dee74d63..22df6579 100644
--- a/src/main/scala/firrtl/traversals/Foreachers.scala
+++ b/src/main/scala/firrtl/traversals/Foreachers.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.traversals
diff --git a/src/main/scala/firrtl/util/BackendCompilationUtilities.scala b/src/main/scala/firrtl/util/BackendCompilationUtilities.scala
index 2ac5b035..8d2d8be9 100644
--- a/src/main/scala/firrtl/util/BackendCompilationUtilities.scala
+++ b/src/main/scala/firrtl/util/BackendCompilationUtilities.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package firrtl.util
diff --git a/src/main/scala/firrtl/util/ClassUtils.scala b/src/main/scala/firrtl/util/ClassUtils.scala
index 34ff60fc..095e875c 100644
--- a/src/main/scala/firrtl/util/ClassUtils.scala
+++ b/src/main/scala/firrtl/util/ClassUtils.scala
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0
+
package firrtl.util
object ClassUtils {
diff --git a/src/main/scala/firrtl/util/TestOptions.scala b/src/main/scala/firrtl/util/TestOptions.scala
index 9ee99f8c..a1b0f4b8 100644
--- a/src/main/scala/firrtl/util/TestOptions.scala
+++ b/src/main/scala/firrtl/util/TestOptions.scala
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0
+
package firrtl.util
import ClassUtils.isClassLoaded
diff --git a/src/main/scala/logger/Logger.scala b/src/main/scala/logger/Logger.scala
index e002db92..fe4b8111 100644
--- a/src/main/scala/logger/Logger.scala
+++ b/src/main/scala/logger/Logger.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package logger
diff --git a/src/main/scala/logger/LoggerAnnotations.scala b/src/main/scala/logger/LoggerAnnotations.scala
index b345d617..c292db87 100644
--- a/src/main/scala/logger/LoggerAnnotations.scala
+++ b/src/main/scala/logger/LoggerAnnotations.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package logger
diff --git a/src/main/scala/logger/LoggerOptions.scala b/src/main/scala/logger/LoggerOptions.scala
index 6cc745b9..c0b5d35c 100644
--- a/src/main/scala/logger/LoggerOptions.scala
+++ b/src/main/scala/logger/LoggerOptions.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package logger
diff --git a/src/main/scala/logger/package.scala b/src/main/scala/logger/package.scala
index 52a3331a..320b06cb 100644
--- a/src/main/scala/logger/package.scala
+++ b/src/main/scala/logger/package.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
import firrtl.AnnotationSeq
import firrtl.options.OptionsView
diff --git a/src/main/scala/logger/phases/AddDefaults.scala b/src/main/scala/logger/phases/AddDefaults.scala
index ec673637..722b7c78 100644
--- a/src/main/scala/logger/phases/AddDefaults.scala
+++ b/src/main/scala/logger/phases/AddDefaults.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package logger.phases
diff --git a/src/main/scala/logger/phases/Checks.scala b/src/main/scala/logger/phases/Checks.scala
index 707118e3..96df4a14 100644
--- a/src/main/scala/logger/phases/Checks.scala
+++ b/src/main/scala/logger/phases/Checks.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package logger.phases
diff --git a/src/main/scala/tutorial/lesson1-circuit-traversal/AnalyzeCircuit.scala b/src/main/scala/tutorial/lesson1-circuit-traversal/AnalyzeCircuit.scala
index 72f50461..23ecb114 100644
--- a/src/main/scala/tutorial/lesson1-circuit-traversal/AnalyzeCircuit.scala
+++ b/src/main/scala/tutorial/lesson1-circuit-traversal/AnalyzeCircuit.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package tutorial
package lesson1
diff --git a/src/main/scala/tutorial/lesson2-ir-fields/AnalyzeCircuit.scala b/src/main/scala/tutorial/lesson2-ir-fields/AnalyzeCircuit.scala
index 11b4519c..a75c19dc 100644
--- a/src/main/scala/tutorial/lesson2-ir-fields/AnalyzeCircuit.scala
+++ b/src/main/scala/tutorial/lesson2-ir-fields/AnalyzeCircuit.scala
@@ -1,4 +1,4 @@
-// See LICENSE for license details.
+// SPDX-License-Identifier: Apache-2.0
package tutorial
package lesson2