parser: Better naming and handling of duplicate tags

Having the same duplicate names of structs and unions was often
confusing.

csym/c/type.go

@@ -344,6 +344,9 @@ func fakeUnionString(t *UnionType) string {
 // IsFakeTag reports whether the tag name is fake (generated by the compiler for
 // symbols lacking a tag name).
 func IsFakeTag(tag string) bool {
+	if i := strings.LastIndex(tag, "_duplicate_"); i > 0 {
+		tag = tag[:i]
+	}
 	if strings.HasPrefix(tag, "_") && strings.HasSuffix(tag, "fake") {
 		s := tag[len("_") : len(tag)-len("fake")]
 		_, err := strconv.Atoi(s)

csym/parse_fixups.go

@@ -287,8 +287,8 @@ func UniqueName(name string, addr uint32) string {
 }
 
 // UniqueTag returns a unique tag based on the given tag and duplicate index.
-func UniqueTag(tag string, idx int) string {
-	return fmt.Sprintf("%s_duplicate_%d", tag, idx)
+func UniqueTag(tag string, typ string, idx int) string {
+	return fmt.Sprintf("%s_duplicate_%s%d", tag, typ, idx)
 }
 
 // UniqueVarName returns a unique variable name based on the given variable
@@ -316,7 +316,7 @@ func UniqueStructTag(structTags map[string][]*c.StructType, t *c.StructType) str
 		if !ok { break } // the tag is unique - done
 		k := SliceIndex(len(structs), func(i int) bool { return structs[i] == t })
 		if k < 0 { k = len(structs) }
-		newTag = UniqueTag(newTag, k)
+		newTag = UniqueTag(newTag, "s", k)
 	}
 	return newTag
 }
@@ -330,7 +330,7 @@ func UniqueUnionTag(unionTags map[string][]*c.UnionType, t *c.UnionType) string
 		if !ok { break } // the tag is unique - done
 		k := SliceIndex(len(unions), func(i int) bool { return unions[i] == t })
 		if k < 0 { k = len(unions) }
-		newTag = UniqueTag(newTag, k)
+		newTag = UniqueTag(newTag, "u", k)
 	}
 	return newTag
 }
@@ -344,7 +344,7 @@ func UniqueEnumTag(EnumTags map[string][]*c.EnumType, t *c.EnumType) string {
 		if !ok { break } // the tag is unique - done
 		k := SliceIndex(len(enums), func(i int) bool { return enums[i] == t })
 		if k < 0 { k = len(enums) }
-		newTag = UniqueTag(newTag, k)
+		newTag = UniqueTag(newTag, "e", k)
 	}
 	return newTag
 }

csym/parse_types.go

@@ -235,20 +235,6 @@ func (p *Parser) parseTypedef(t sym.Type, dims []uint32, tag, name string) {
 
 // ### [ Helper functions ] ####################################################
 
-// Duplicate tag format string.
-const duplicateTagFormat = "%s_duplicate_%d"
-
-// uniqueTag returns a unique tag based on the given tag and set of present
-// tags.
-func uniqueTag(tag string, tags map[string]bool) string {
-	newTag := tag
-	for i := 0; tags[newTag]; i++ {
-		newTag = fmt.Sprintf(duplicateTagFormat, tag, i)
-	}
-	tags[newTag] = true
-	return newTag
-}
-
 // Duplicate enum member format string.
 const duplicateEnumFormat = "%s_DUPLICATE_%d"