tint: Add operator support to intrinsic-gen

Adapt the builtin parsing and resolving to also support operators.
Will be used to generate intrinsic table entries for operators.

This will simplify maintenance of the operators, and will greatly
simplify the [AbstractInt -> i32|u32] [AbstractFloat -> f32|f16] logic.

Bug: tint:1504
Change-Id: Id75735ea24e501877418812185796f3fba88a521
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/89026
Commit-Queue: Ben Clayton <bclayton@chromium.org>
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Dan Sinclair <dsinclair@chromium.org>

tools/src/cmd/intrinsic-gen/sem/sem.go

@@ -26,7 +26,8 @@ type Sem struct {
 	Types        []*Type
 	TypeMatchers []*TypeMatcher
 	EnumMatchers []*EnumMatcher
-	Functions    []*Function
+	Builtins     []*Intrinsic
+	Operators    []*Intrinsic
 	// Maximum number of open-types used across all builtins
 	MaxOpenTypes int
 	// Maximum number of open-numbers used across all builtins
@@ -42,7 +43,8 @@ func New() *Sem {
 		Types:        []*Type{},
 		TypeMatchers: []*TypeMatcher{},
 		EnumMatchers: []*EnumMatcher{},
-		Functions:    []*Function{},
+		Builtins:     []*Intrinsic{},
+		Operators:    []*Intrinsic{},
 	}
 }
 
@@ -121,16 +123,16 @@ type TemplateNumberParam struct {
 	Name string
 }
 
-// Function describes the overloads of a builtin function
-type Function struct {
+// Intrinsic describes the overloads of a builtin or operator
+type Intrinsic struct {
 	Name      string
 	Overloads []*Overload
 }
 
-// Overload describes a single overload of a function
+// Overload describes a single overload of a builtin or operator
 type Overload struct {
-	Decl             ast.FunctionDecl
-	Function         *Function
+	Decl             ast.IntrinsicDecl
+	Intrinsic        *Intrinsic
 	TemplateParams   []TemplateParam
 	OpenTypes        []*TemplateTypeParam
 	OpenNumbers      []TemplateParam
@@ -164,7 +166,13 @@ func (u StageUses) List() []string {
 
 // Format implements the fmt.Formatter interface
 func (o Overload) Format(w fmt.State, verb rune) {
-	fmt.Fprintf(w, "fn %v", o.Function.Name)
+	switch o.Decl.Kind {
+	case ast.Builtin:
+		fmt.Fprintf(w, "fn ")
+	case ast.Operator:
+		fmt.Fprintf(w, "op ")
+	}
+	fmt.Fprintf(w, "%v", o.Intrinsic.Name)
 	if len(o.TemplateParams) > 0 {
 		fmt.Fprintf(w, "<")
 		for i, t := range o.TemplateParams {