[demangler] refactor SpecialSubKind
Code generating the special substitutions in std is a switch statement
with each case block containing the same conststruction template. It
is more efficient to commonize that after the switch, having
determined which SubKind to create. Also, let's sort the cases.
Reviewed By: ChuanqiXu
Differential Revision: https://reviews.llvm.org/D118131
GitOrigin-RevId: 4e5fce58485cc69ee69da10e26a338ceeef280a0
diff --git a/src/demangle/ItaniumDemangle.h b/src/demangle/ItaniumDemangle.h
index 45bb741..98489e4 100644
--- a/src/demangle/ItaniumDemangle.h
+++ b/src/demangle/ItaniumDemangle.h
@@ -5448,37 +5448,34 @@
return nullptr;
if (look() >= 'a' && look() <= 'z') {
- Node *SpecialSub;
+ SpecialSubKind Kind;
switch (look()) {
case 'a':
- ++First;
- SpecialSub = make<SpecialSubstitution>(SpecialSubKind::allocator);
+ Kind = SpecialSubKind::allocator;
break;
case 'b':
- ++First;
- SpecialSub = make<SpecialSubstitution>(SpecialSubKind::basic_string);
- break;
- case 's':
- ++First;
- SpecialSub = make<SpecialSubstitution>(SpecialSubKind::string);
- break;
- case 'i':
- ++First;
- SpecialSub = make<SpecialSubstitution>(SpecialSubKind::istream);
- break;
- case 'o':
- ++First;
- SpecialSub = make<SpecialSubstitution>(SpecialSubKind::ostream);
+ Kind = SpecialSubKind::basic_string;
break;
case 'd':
- ++First;
- SpecialSub = make<SpecialSubstitution>(SpecialSubKind::iostream);
+ Kind = SpecialSubKind::iostream;
+ break;
+ case 'i':
+ Kind = SpecialSubKind::istream;
+ break;
+ case 'o':
+ Kind = SpecialSubKind::ostream;
+ break;
+ case 's':
+ Kind = SpecialSubKind::string;
break;
default:
return nullptr;
}
+ ++First;
+ auto *SpecialSub = make<SpecialSubstitution>(Kind);
if (!SpecialSub)
return nullptr;
+
// Itanium C++ ABI 5.1.2: If a name that would use a built-in <substitution>
// has ABI tags, the tags are appended to the substitution; the result is a
// substitutable component.
