[clang-repl] Extend the C support. (#89804)

The IdResolver chain is the main way for C to implement lookup rules.
Every new partial translation unit caused clang to exit the top-most
scope which in turn cleaned up the IdResolver chain. That was not an
issue for C++ because its lookup is implemented on the level of
declaration contexts.

This patch keeps the IdResolver chain across partial translation units
maintaining proper C-style lookup infrastructure.

1 files changed, 11 insertions, 2 deletions

diff --git a/clang/lib/Interpreter/IncrementalParser.cpp b/clang/lib/Interpreter/IncrementalParser.cpp
index ef90fe9..5bc8385 100644
--- a/clang/lib/Interpreter/IncrementalParser.cpp
+++ b/clang/lib/Interpreter/IncrementalParser.cpp
@@ -387,8 +387,7 @@ std::unique_ptr<llvm::Module> IncrementalParser::GenModule() {
 
 void IncrementalParser::CleanUpPTU(PartialTranslationUnit &PTU) {
   TranslationUnitDecl *MostRecentTU = PTU.TUPart;
-  TranslationUnitDecl *FirstTU = MostRecentTU->getFirstDecl();
-  if (StoredDeclsMap *Map = FirstTU->getPrimaryContext()->getLookupPtr()) {
+  if (StoredDeclsMap *Map = MostRecentTU->getPrimaryContext()->getLookupPtr()) {
     for (auto &&[Key, List] : *Map) {
       DeclContextLookupResult R = List.getLookupResult();
       std::vector<NamedDecl *> NamedDeclsToRemove;
@@ -407,6 +406,16 @@ void IncrementalParser::CleanUpPTU(PartialTranslationUnit &PTU) {
       }
     }
   }
+
+  // FIXME: We should de-allocate MostRecentTU
+  for (Decl *D : MostRecentTU->decls()) {
+    auto *ND = dyn_cast<NamedDecl>(D);
+    if (!ND)
+      continue;
+    // Check if we need to clean up the IdResolver chain.
+    if (ND->getDeclName().getFETokenInfo())
+      getCI()->getSema().IdResolver.RemoveDecl(ND);
+  }
 }
 
 llvm::StringRef IncrementalParser::GetMangledName(GlobalDecl GD) const {