LLVM Changelog

Breaking changes encountered during each LLVM upgrade, with upstream commit references.

LLVM 21 → 22

Type System

Change	Commit	PR	Impact on clice
`NestedNameSpecifier` redesigned as a value type; `ElaboratedType` removed — tag/typedef/using/template-specialization types now carry the elaborated keyword and qualifier themselves. NNS kinds reduced to `Null`/`Global`/`Type`/`Namespace`/`MicrosoftSuper`; the old `Identifier` kind is now a `DependentNameType` component of kind `Type`.	`91cdd35008e9`	#147835	Rewrote NNS handling in the template resolver, semantic visitor, unifier, display and USR generation. `rewrite_specifier` collapsed to a single type-component rewrite; NNS occurrence handling dropped the `Identifier`/`NamespaceAlias` cases (dependent chains are now visited as `DependentNameTypeLoc`s).
`DependentTemplateSpecializationType` removed; a dependent specialization is a `TemplateSpecializationType` whose `TemplateName` is a `DependentTemplateName`. `ASTContext::getDependentTemplateSpecializationType` gone; `getTemplateSpecializationType` takes an `ElaboratedTypeKeyword` first parameter.	`ba9d1c41c41d`	#158109	Resolver's DTST lookup/rewrite/pseudo-SFINAE paths merged into the TST paths, keyed on `getAsDependentTemplateName()`.
`InjectedClassNameType` is now a `TagType` subclass and no longer stores the injected specialization; use `CXXRecordDecl::getCanonicalTemplateSpecializationType(Ctx)`. `TagDecl::getTypeForDecl` deleted; use `ASTContext::getCanonicalTagType`.	`91cdd35008e9`	#147835	Resolver, unifier, USR generation and hover layout info migrated to the canonical accessors.
`NamespaceBaseDecl` introduced; a `Namespace` NNS component stores it (covers both namespaces and namespace aliases).	`4a9eaad9e128`	#149123	Namespace lookup goes through `getAsNamespaceAndPrefix().Namespace->getNamespace()`; alias occurrences reference the base decl directly.
`UsingType::getFoundDecl`/`getUnderlyingType` renamed to `getDecl`/`desugar`; `TypedefTypeLoc::getTypedefNameDecl` is `getDecl`.	`91cdd35008e9`	#147835	Mechanical renames in unifier, resolver and semantic visitor.
Implicit variable template specializations no longer store written template arguments.	`1cb47c19f8ec`	#156329	`display::template_args` falls back to the converted argument list, so hover titles print `baz<ns::X<int>>` (converted, qualified) instead of the as-written form.
`RecursiveASTVisitor` type traversals take a `TraverseQualifier` flag; `DynTypedNode::getSourceRange` takes `IncludeQualifier` (default excludes the qualifier of qualified type locs).	`91cdd35008e9`	#147835	Semantic visitor overrides updated; selection-tree node ranges now exclude qualifiers (matching clangd), so a cursor on a dependent name selects its `DependentNameTypeLoc` name token.

Driver / Frontend

Change	Commit	PR	Impact on clice
Option handling split out of clangDriver into a clangOptions library: `clang/Driver/Options.inc` → `clang/Options/Options.inc`, `GetResourcesPath` → `clang/Options/OptionUtils.h` (namespace `clang`).	`f63d33da0a51`	#167374	Include-path and call-site updates in the argument parser.
`OptTable` gained subcommand support: the `OPTION` record has a trailing `SUBCOMMANDIDS_OFFSET` column.	`fdbd17d1fb0d`	#155026	The `OPTION` macros expanding `Options.inc` take the extra parameter.
`clang::createInvocation` moved to `clang/Driver/CreateInvocationFromArgs.h`.	`d090311aa7df`	#169599	Include updates in compilation and scan.
`CompilerInstance` owns its VFS explicitly: seed it with `setVirtualFileSystem`/`createVirtualFileSystem` (the latter subsumes `createVFSFromCompilerInvocation`), then `createDiagnostics(Client, ShouldOwnClient)` and `createFileManager()` take no VFS.	`30633f308941`	#158381	Compilation and scan set the VFS on the instance before creating diagnostics and the file manager.

Other

Change	Commit	PR	Impact on clice
`llvm::sys::fs::make_absolute(current_directory, path)` moved to `llvm::sys::path::make_absolute`.	`f122484b998d`	#161459	Call-site update in header search config.
`size_t` and friends are named sugar types (`__size_t`), so e.g. `operator new`'s parameter prints as `__size_t` with an `aka unsigned long`.	`7c402b8b81d2`	#149613	Hover snapshots updated.
Anonymous tag types print as `(unnamed enum)`/`(unnamed struct)` uniformly.	`4ef641916408`	#169445	Hover snapshots updated.
`PrintingPolicy::SuppressScope` now also drops written qualifiers of template names, and canonical tag types print fully qualified.	`91cdd35008e9`	#147835	Inlay type hints lose nested-class scopes (`Nested<int>` instead of `S2::Nested<int>`, matching clangd); hover of `this` prints the namespace-qualified class type.