[Demangle] demangle builtin type transformations (#65902)

Fixed: https://github.com/llvm/llvm-project/issues/62127
https://reviews.llvm.org/D116203 introduced several compiler builtin
equivalents of the unary type traits. In some cases (e.g. template)
those builtin will be dependent and need to be mangle.
This patch add the check for `u{builtin}I{type}E` to demangle it.

Reviewed By: rjmccall

Differential Revision: https://reviews.llvm.org/D148465

3 files changed, 36 insertions, 1 deletions

diff --git a/libcxxabi/src/demangle/ItaniumDemangle.h b/libcxxabi/src/demangle/ItaniumDemangle.h
index 6fdfe38..2336b84 100644
--- a/libcxxabi/src/demangle/ItaniumDemangle.h
+++ b/libcxxabi/src/demangle/ItaniumDemangle.h
@@ -534,6 +534,23 @@ public:
   }
 };
 
+class TransformedType : public Node {
+  std::string_view Transform;
+  Node *BaseType;
+public:
+  TransformedType(std::string_view Transform_, Node *BaseType_)
+      : Node(KTransformedType), Transform(Transform_), BaseType(BaseType_) {}
+
+  template<typename Fn> void match(Fn F) const { F(Transform, BaseType); }
+
+  void printLeft(OutputBuffer &OB) const override {
+    OB += Transform;
+    OB += '(';
+    BaseType->print(OB);
+    OB += ')';
+  }
+};
+
 struct AbiTagAttr : Node {
   Node *Base;
   std::string_view Tag;
@@ -4125,7 +4142,15 @@ Node *AbstractManglingParser<Derived, Alloc>::parseType() {
     // Typically, <builtin-type>s are not considered substitution candidates,
     // but the exception to that exception is vendor extended types (Itanium C++
     // ABI 5.9.1).
-    Result = make<NameType>(Res);
+    if (consumeIf('I')) {
+      Node *BaseType = parseType();
+      if (BaseType == nullptr)
+        return nullptr;
+      if (!consumeIf('E'))
+        return nullptr;
+      Result = make<TransformedType>(Res, BaseType);
+    } else
+      Result = make<NameType>(Res);
     break;
   }
   case 'D':
diff --git a/libcxxabi/src/demangle/ItaniumNodes.def b/libcxxabi/src/demangle/ItaniumNodes.def
index 74dc709..e27c111 100644
--- a/libcxxabi/src/demangle/ItaniumNodes.def
+++ b/libcxxabi/src/demangle/ItaniumNodes.def
@@ -19,6 +19,7 @@ NODE(QualType)
 NODE(ConversionOperatorType)
 NODE(PostfixQualifiedType)
 NODE(ElaboratedTypeSpefType)
+NODE(TransformedType)
 NODE(NameType)
 NODE(AbiTagAttr)
 NODE(EnableIfAttr)
diff --git a/libcxxabi/test/test_demangle.pass.cpp b/libcxxabi/test/test_demangle.pass.cpp
index 47cc29b..df7bedc 100644
--- a/libcxxabi/test/test_demangle.pass.cpp
+++ b/libcxxabi/test/test_demangle.pass.cpp
@@ -30161,6 +30161,15 @@ const char* cases[][2] =
      " std::allocator<char>>::basic_string()"},
     {"_ZN1SB8ctor_tagC2Ev", "S[abi:ctor_tag]::S()"},
     {"_ZN1SB8ctor_tagD2Ev", "S[abi:ctor_tag]::~S()"},
+
+    // clang builtin type transform
+    {"_Z2f5IiEvu22__add_lvalue_referenceIT_E", "void f5<int>(__add_lvalue_reference(int))"},
+    {"_Z2f5IiEvu13__add_pointerIT_E", "void f5<int>(__add_pointer(int))"},
+    {"_Z2f5IiEvu7__decayIT_E", "void f5<int>(__decay(int))"},
+    {"_Z2f5IjEvu13__make_signedIT_E", "void f5<unsigned int>(__make_signed(unsigned int))"},
+    {"_Z2f5IKiEvu14__remove_constIT_E", "void f5<int const>(__remove_const(int const))"},
+    {"_Z2f5IPiEvu16__remove_pointerIT_E", "void f5<int*>(__remove_pointer(int*))"},
+    {"_Z2f5IiEvu14__remove_cvrefIT_E", "void f5<int>(__remove_cvref(int))"},
 };
 
 const unsigned N = sizeof(cases) / sizeof(cases[0]);