tint: intrinsics.def Support [[precedence]] decoration

Add support for a [[precedence(N)]] decoration on intrinsic table type
declarations. This will be used to ensure the type with the lowest
conversion rank is matched when a matcher could match multiple types
for a given abstract numeric argument type.

Bug: tint:1504
Change-Id: I96475b000c0917bbfa4e2873b1731ce048b96a7d
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/90664
Reviewed-by: David Neto <dneto@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>

src/tint/intrinsics.def

@@ -62,13 +62,18 @@ enum texel_format {
 
 ////////////////////////////////////////////////////////////////////////////////
 // WGSL primitive types                                                       //
+// Types may be decorated with [[precedence(N)]] to prioritize which type     //
+// will be picked when multiple types of a matcher match.                     //
+// This is used to ensure that abstract numerical types materialize to the    //
+// concrete type with the lowest conversion rank.                             //
+// Types with higher the precedence values will be matched first.             //
 ////////////////////////////////////////////////////////////////////////////////
 
 // https://gpuweb.github.io/gpuweb/wgsl/#plain-types-section
 type bool
-type f32
-type i32
-type u32
+[[precedence(2)]] type i32
+[[precedence(1)]] type u32
+[[precedence(0)]] type f32
 type vec2<T>
 type vec3<T>
 type vec4<T>

src/tint/resolver/intrinsic_table.inl.tmpl

@@ -248,7 +248,7 @@ class {{$class}} : public TypeMatcher {
 };
 
 const sem::Type* {{$class}}::Match(MatchState& state, const sem::Type* ty) const {
-{{- range .Types }}
+{{- range .PrecedenceSortedTypes }}
   if (match_{{.Name}}(ty)) {
     return build_{{.Name}}(state);
   }