Fixup/cleanup IR::Type::width_bits()

- this method is used by backends to get the size of a type, and should only be used for Types for which the concept of `size in bits' makes sense
p4lang · Aug 9, 2024 · 97771fd · 97771fd
1 parent 63c4071
commit 97771fd
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Showing 4 changed files with 9 additions and 3 deletions.
diff --git a/backends/bmv2/psa_switch/psaSwitch.h b/backends/bmv2/psa_switch/psaSwitch.h
@@ -39,7 +39,9 @@ class PsaSwitchExpressionConverter : public ExpressionConverter {
             auto jsn = new Util::JsonObject();
             jsn->emplace("name", param->toString());
             jsn->emplace("type", "hexstr");
-            auto bitwidth = param->type->width_bits();
+            // FIXME -- how big is a PSA_CounterType_t?  Being an enum type, we can't
+            // sensibly call param->width_bits() here.
+            auto bitwidth = 0;
 
             // encode the counter type from enum -> int
             if (fieldName == "BYTES") {

diff --git a/ir/base.def b/ir/base.def
@@ -36,7 +36,7 @@ abstract Type {
     typedef Type_Void           Void;
 #end
     /// Well-defined only for types with fixed width
-    virtual int width_bits() const { return 0; }
+    virtual int width_bits() const { BUG("width_bits() on type with unknown size: %1%", this); }
     /// When possible returns the corresponding type that can be inserted
     /// in a P4 program; may return a Type_Name
     virtual const Type* getP4Type() const = 0;

diff --git a/ir/expression.def b/ir/expression.def
@@ -321,7 +321,7 @@ class TypeNameExpression : Expression {
     dbprint{ out << typeName; }
     toString { return typeName->toString(); }
     validate { BUG_CHECK(typeName->is<Type_Name>() || typeName->is<Type_Specialized>(),
-                         "%1 unexpected type in TypeNameExpression", typeName); }
+                         "%1% unexpected type in TypeNameExpression", typeName); }
 }
 
 class Slice : Operation_Ternary {

diff --git a/ir/type.def b/ir/type.def
@@ -182,6 +182,7 @@ class Type_Varbits : Type_Base {
     static Type_Varbits get();
     toString{ return "varbit<"_cs + Util::toString(size) + ">"_cs; }
     dbprint { out << "varbit<" << size << ">"; }
+    int width_bits() const override { return size; }
 }
 
 class Parameter : Declaration, IAnnotated {
@@ -268,6 +269,7 @@ class Type_InfInt : Type, ITypeVar {
         return true; /* ignore declid */
     }
     const Type* getP4Type() const override { return this; }
+    int width_bits() const override { return 0; }
 }
 
 class Type_Dontcare : Type_Base {
@@ -583,6 +585,7 @@ class Type_Stack : Type_Indexed, Type {
     static const cstring pop_front;
     const Type* getP4Type() const override
     { return new IR::Type_Stack(srcInfo, elementType->getP4Type(), size); }
+    int width_bits() const override { return getSize() * elementType->width_bits(); }
 }
 
 /** Given a declaration
@@ -680,6 +683,7 @@ class Type_SerEnum : Type_Declaration, ISimpleNamespace, IAnnotated {
         return members.getDeclaration(name); }
 #nodbprint
     validate{ members.check_null(); }
+    int width_bits() const override { return type->width_bits(); }
 }
 
 class Type_Table : Type, IApply {