Clangtool: Fix build breakage on LLVM < 22

Internal rebase to llvmorg-21-init-16856-g696c0f92e0 lead to use of APIs only available in LLVM 22 and later.

PiperOrigin-RevId: 803426800
Change-Id: I4d7193ae133c6b378228a7a92a7e1677c1fa1ee0

Author: cblichmann

sandboxed_api/tools/clang_generator/types.cc

@@ -144,15 +144,23 @@ void TypeCollector::CollectRelatedTypes(clang::QualType qual) {
   // - Nested types are skipped and the enclosing type is collected which is
   //   enough to reconstruct the AST when emitting the SAPI header.
   if (const auto* record_type = qual->getAs<clang::RecordType>()) {
+#if LLVM_VERSION_MAJOR >= 22
     const clang::RecordDecl* decl = record_type->getOriginalDecl();
+#else
+    const clang::RecordDecl* decl = record_type->getDecl();
+#endif
     if (!IsProtoBuf(decl)) {
       for (const clang::FieldDecl* field : decl->fields()) {
         CollectRelatedTypes(field->getType());
       }
     }
     const clang::RecordDecl* outer = decl->getOuterLexicalRecordContext();
     decl = outer ? outer : decl;
+#if LLVM_VERSION_MAJOR >= 22
     collected_.insert(decl->getASTContext().getCanonicalTagType(decl));
+#else
+    collected_.insert(clang::QualType(decl->getTypeForDecl(), /*Quals=*/0));
+#endif
   }
 
   // For TypedefType; Collect the underlying type.
@@ -205,10 +213,16 @@ void TypeCollector::CollectRelatedTypes(clang::QualType qual) {
   // For Enumtype, recursively call CollectRelatedTypes to collect the
   // underlying integer type of enum classes as well, as it may be a typedef.
   if (qual->isEnumeralType()) {
+#if LLVM_VERSION_MAJOR >= 22
     qual = qual.getCanonicalType();
+#endif
     if (const clang::EnumType* enum_type = qual->getAs<clang::EnumType>()) {
-      if (const clang::EnumDecl* decl = enum_type->getOriginalDecl();
-          decl->isFixed()) {
+#if LLVM_VERSION_MAJOR >= 22
+      const clang::EnumDecl* decl = enum_type->getOriginalDecl();
+#else
+      const clang::EnumDecl* decl = enum_type->getDecl();
+#endif
+      if (decl->isFixed()) {
         CollectRelatedTypes(decl->getIntegerType());
       }
     }
@@ -419,10 +433,18 @@ std::string TypeMapper::MapQualType(clang::QualType qual) const {
         break;
     }
   } else if (const auto* enum_type = qual->getAs<clang::EnumType>()) {
+#if LLVM_VERSION_MAJOR >= 22
     clang::EnumDecl* enum_decl = enum_type->getOriginalDecl();
+#else
+    clang::EnumDecl* enum_decl = enum_type->getDecl();
+#endif
     if (auto* typedef_decl = enum_decl->getTypedefNameForAnonDecl()) {
+#if LLVM_VERSION_MAJOR >= 22
       qual = context_.getTypedefType(clang::ElaboratedTypeKeyword::None,
                                      /*Qualifier=*/std::nullopt, typedef_decl);
+#else
+      qual = typedef_decl->getUnderlyingType().getDesugaredType(context_);
+#endif
     }
     return absl::StrCat("::sapi::v::IntBase<",
                         GetFullyQualifiedName(context_, qual, ns_to_strip_),