[ImportVerilog] Support parameter constants. (#7083)

llvm · May 30, 2024 · 76b65f8 · 76b65f8
1 parent 21269d5
commit 76b65f8
Show file tree

Hide file tree

Showing 4 changed files with 106 additions and 0 deletions.
diff --git a/include/circt/Dialect/Moore/MooreOps.td b/include/circt/Dialect/Moore/MooreOps.td
@@ -297,6 +297,36 @@ def ConstantOp : MooreOp<"constant", [Pure]> {
   ];
 }
 
+def Parameter : I32EnumAttrCase<"Parameter", 0, "parameter">;
+def LocalParameter : I32EnumAttrCase<"LocalParameter", 1, "localparam">;
+def SpecParameter : I32EnumAttrCase<"SpecParameter", 2, "specparam">;
+
+def NamedConstAttr : I32EnumAttr<"NamedConst", "elaboration-time constants", 
+       [Parameter, LocalParameter, SpecParameter]>{
+    let cppNamespace = "circt::moore";
+}
+
+def NamedConstantOp : MooreOp<"named_constant", [
+  SameOperandsAndResultType,
+  DeclareOpInterfaceMethods<OpAsmOpInterface, ["getAsmResultNames"]>
+]>{
+  let summary = "An elaboration time constant expression";
+  let description = [{
+    Constants are named data objects that never change. SystemVerilog provides 
+    three elaboration-time constants: parameter, localparam, and specparam.
+
+    See IEEE 1800-2017 § 6.20 "Constants".
+  }];
+  let arguments = (ins StrAttr:$name, 
+                       NamedConstAttr:$kind, 
+                       UnpackedType:$value);
+  let results = (outs UnpackedType:$result);
+  let assemblyFormat = [{
+    `` custom<ImplicitSSAName>($name) $kind $value attr-dict
+    `:` type($result)
+  }];
+}
+
 def ConversionOp : MooreOp<"conversion", [Pure]> {
   let summary = "A type conversion";
   let description = [{

diff --git a/lib/Conversion/ImportVerilog/Structure.cpp b/lib/Conversion/ImportVerilog/Structure.cpp
@@ -191,6 +191,55 @@ struct MemberVisitor {
     return context.convertStatement(procNode.getBody());
   }
 
+  // Handle parameters.
+  LogicalResult visit(const slang::ast::ParameterSymbol &paramNode) {
+    auto type = context.convertType(*paramNode.getDeclaredType());
+    if (!type)
+      return failure();
+
+    const auto *init = paramNode.getInitializer();
+    // skip parameters without value.
+    if (!init)
+      return success();
+    Value initial = context.convertExpression(*init);
+    if (!initial)
+      return failure();
+
+    auto namedConstantOp = builder.create<moore::NamedConstantOp>(
+        loc, type, builder.getStringAttr(paramNode.name),
+        paramNode.isLocalParam()
+            ? moore::NamedConstAttr::get(context.getContext(),
+                                         moore::NamedConst::LocalParameter)
+            : moore::NamedConstAttr::get(context.getContext(),
+                                         moore::NamedConst::Parameter),
+        initial);
+    context.valueSymbols.insert(&paramNode, namedConstantOp);
+    return success();
+  }
+
+  // Handle specparam.
+  LogicalResult visit(const slang::ast::SpecparamSymbol &spNode) {
+    auto type = context.convertType(*spNode.getDeclaredType());
+    if (!type)
+      return failure();
+
+    const auto *init = spNode.getInitializer();
+    // skip specparam without value.
+    if (!init)
+      return success();
+    Value initial = context.convertExpression(*init);
+    if (!initial)
+      return failure();
+
+    auto namedConstantOp = builder.create<moore::NamedConstantOp>(
+        loc, type, builder.getStringAttr(spNode.name),
+        moore::NamedConstAttr::get(context.getContext(),
+                                   moore::NamedConst::SpecParameter),
+        initial);
+    context.valueSymbols.insert(&spNode, namedConstantOp);
+    return success();
+  }
+
   // Ignore statement block symbols. These get generated by Slang for blocks
   // with variables and other declarations. For example, having an initial
   // procedure with a variable declaration, such as `initial begin int x;

diff --git a/lib/Dialect/Moore/MooreOps.cpp b/lib/Dialect/Moore/MooreOps.cpp
@@ -133,6 +133,14 @@ void ConstantOp::build(OpBuilder &builder, OperationState &result, IntType type,
         APInt(type.getWidth(), (uint64_t)value, /*isSigned=*/true));
 }
 
+//===----------------------------------------------------------------------===//
+// NamedConstantOp
+//===----------------------------------------------------------------------===//
+
+void NamedConstantOp::getAsmResultNames(OpAsmSetValueNameFn setNameFn) {
+  setNameFn(getResult(), getName());
+}
+
 //===----------------------------------------------------------------------===//
 // ConcatOp
 //===----------------------------------------------------------------------===//

diff --git a/test/Conversion/ImportVerilog/basic.sv b/test/Conversion/ImportVerilog/basic.sv
@@ -78,6 +78,25 @@ module Basic;
   bit [0:0] b1;
   bit b2 = b1;
 
+  // CHECK: [[TMP1:%.+]] = moore.constant 1 : i32
+  // CHECK: [[TMP2:%.+]] = moore.conversion [[TMP1]] : !moore.i32 -> !moore.l32
+  // CHECK: %p1 = moore.named_constant parameter [[TMP2]] : l32
+  parameter p1 = 1;
+  // CHECK: %p2 = moore.named_constant parameter %p1 : l32
+  parameter p2 = p1;
+  // CHECK: [[TMP1:%.+]] = moore.constant 2 : i32
+  // CHECK: [[TMP2:%.+]] = moore.conversion [[TMP1]] : !moore.i32 -> !moore.l32
+  // CHECK: %lp1 = moore.named_constant localparam [[TMP2]] : l32
+  localparam lp1 = 2;
+  // CHECK: %lp2 = moore.named_constant localparam %lp1 : l32
+  localparam lp2 = lp1;
+  // CHECK: [[TMP1:%.+]] = moore.constant 3 : i32
+  // CHECK: [[TMP2:%.+]] = moore.conversion [[TMP1]] : !moore.i32 -> !moore.l32
+  // CHECK: %sp1 = moore.named_constant specparam [[TMP2]] : l32
+  specparam sp1 = 3;
+  // CHECK: %sp2 = moore.named_constant specparam %sp1 : l32
+  specparam sp2 = sp1;
+
   // CHECK: moore.procedure initial {
   // CHECK: }
   initial;