[FIRRTL] Add a pass to convert VoB -> BoV conversion (#4654)

This pass converts objects with the shape vector<bundle> to bundle<vector>.
llvm · Mar 1, 2023 · 38b1f39 · 38b1f39
1 parent 0e06b7c
commit 38b1f39
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Showing 9 changed files with 1,800 additions and 3 deletions.
diff --git a/include/circt/Dialect/FIRRTL/FIRRTLTypesImpl.td b/include/circt/Dialect/FIRRTL/FIRRTLTypesImpl.td
@@ -117,6 +117,10 @@ def FVectorTypeImpl : FIRRTLImplType<"FVector", [FieldIDTypeInterface]> {
     /// return the index of the parent element.
     uint64_t getIndexForFieldID(uint64_t fieldID);
 
+    /// Find the index of the element that contains the given fieldID.
+    /// As well, rebase the fieldID to the element.
+    std::pair<uint64_t, uint64_t> getIndexAndSubfieldID(uint64_t fieldID);
+
     /// Strip off a single layer of this type and return the sub-type and a
     /// field ID targeting the same field, but rebased on the sub-type.
     std::pair<FIRRTLBaseType, uint64_t> getSubTypeByFieldID(uint64_t fieldID);
@@ -200,6 +204,10 @@ def BundleImpl : FIRRTLImplType<"Bundle", [FieldIDTypeInterface]> {
     /// index of the parent field.
     uint64_t getIndexForFieldID(uint64_t fieldID);
 
+    /// Find the index of the element that contains the given fieldID.
+    /// As well, rebase the fieldID to the element.
+    std::pair<uint64_t, uint64_t> getIndexAndSubfieldID(uint64_t fieldID);
+
     /// Strip off a single layer of this type and return the sub-type and a
     /// field ID targeting the same field, but rebased on the sub-type.
     std::pair<FIRRTLBaseType, uint64_t> getSubTypeByFieldID(uint64_t fieldID);

diff --git a/include/circt/Dialect/FIRRTL/FIRRTLVisitors.h b/include/circt/Dialect/FIRRTL/FIRRTLVisitors.h
@@ -49,7 +49,7 @@ class ExprVisitor {
             // Miscellaneous.
             BitsPrimOp, HeadPrimOp, MuxPrimOp, PadPrimOp, ShlPrimOp, ShrPrimOp,
             TailPrimOp, VerbatimExprOp, HWStructCastOp, BitCastOp, RefSendOp,
-            RefResolveOp, mlir::UnrealizedConversionCastOp>(
+            RefResolveOp, RefSubOp, mlir::UnrealizedConversionCastOp>(
             [&](auto expr) -> ResultType {
               return thisCast->visitExpr(expr, args...);
             })
@@ -153,6 +153,7 @@ class ExprVisitor {
   HANDLE(VerbatimExprOp, Unhandled);
   HANDLE(RefSendOp, Unhandled);
   HANDLE(RefResolveOp, Unhandled);
+  HANDLE(RefSubOp, Unhandled);
 
   // Conversions.
   HANDLE(HWStructCastOp, Unhandled);

diff --git a/include/circt/Dialect/FIRRTL/Passes.h b/include/circt/Dialect/FIRRTL/Passes.h
@@ -74,6 +74,8 @@ createCreateSiFiveMetadataPass(bool replSeqMem = false,
 
 std::unique_ptr<mlir::Pass> createWireDFTPass();
 
+std::unique_ptr<mlir::Pass> createVBToBVPass();
+
 std::unique_ptr<mlir::Pass> createAddSeqMemPortsPass();
 
 std::unique_ptr<mlir::Pass> createDedupPass();

diff --git a/include/circt/Dialect/FIRRTL/Passes.td b/include/circt/Dialect/FIRRTL/Passes.td
@@ -642,4 +642,13 @@ def InnerSymbolDCE : Pass<"firrtl-inner-symbol-dce", "mlir::ModuleOp"> {
   ];
 }
 
+def VBToBV : Pass<"firrtl-vb-to-bv", "firrtl::CircuitOp"> {
+  let summary = "Transform vector-of-bundles to bundle-of-vectors";
+  let description = [{
+    This pass converts vectors containing bundles, into bundles containing
+    vectors.
+  }];
+  let constructor = "circt::firrtl::createVBToBVPass()";
+}
+
 #endif // CIRCT_DIALECT_FIRRTL_PASSES_TD
diff --git a/lib/Dialect/FIRRTL/FIRRTLTypes.cpp b/lib/Dialect/FIRRTL/FIRRTLTypes.cpp
@@ -913,6 +913,13 @@ uint64_t BundleType::getIndexForFieldID(uint64_t fieldID) {
   return std::distance(fieldIDs.begin(), it);
 }
 
+std::pair<uint64_t, uint64_t>
+BundleType::getIndexAndSubfieldID(uint64_t fieldID) {
+  auto index = getIndexForFieldID(fieldID);
+  auto elementFieldID = getFieldID(index);
+  return {index, fieldID - elementFieldID};
+}
+
 std::pair<FIRRTLBaseType, uint64_t>
 BundleType::getSubTypeByFieldID(uint64_t fieldID) {
   if (fieldID == 0)
@@ -1011,12 +1018,18 @@ uint64_t FVectorType::getIndexForFieldID(uint64_t fieldID) {
   return (fieldID - 1) / (getElementType().getMaxFieldID() + 1);
 }
 
+std::pair<uint64_t, uint64_t>
+FVectorType::getIndexAndSubfieldID(uint64_t fieldID) {
+  auto index = getIndexForFieldID(fieldID);
+  auto elementFieldID = getFieldID(index);
+  return {index, fieldID - elementFieldID};
+}
+
 std::pair<FIRRTLBaseType, uint64_t>
 FVectorType::getSubTypeByFieldID(uint64_t fieldID) {
   if (fieldID == 0)
     return {*this, 0};
-  auto subfieldIndex = getIndexForFieldID(fieldID);
-  return {getElementType(), fieldID - getFieldID(subfieldIndex)};
+  return {getElementType(), getIndexForFieldID(fieldID)};
 }
 
 uint64_t FVectorType::getMaxFieldID() {

diff --git a/lib/Dialect/FIRRTL/Transforms/CMakeLists.txt b/lib/Dialect/FIRRTL/Transforms/CMakeLists.txt
@@ -36,6 +36,7 @@ add_circt_dialect_library(CIRCTFIRRTLTransforms
   ResolveTraces.cpp
   RemoveUnusedPorts.cpp
   SFCCompat.cpp
+  VBToBV.cpp
   WireDFT.cpp
 
   DEPENDS