[clang] [clang][analyzer] Forward CTU-import failure conditions (PR #189064)

[Arseniy Zaostrovnykh via cfe-commits]

================
@@ -379,43 +406,98 @@ CrossTranslationUnitContext::getCrossTUDefinition(const VarDecl *VD,
                                   DisplayCTUProgress);
 }
 
-void CrossTranslationUnitContext::emitCrossTUDiagnostics(const IndexError &IE,
-                                                         SourceLocation Loc) {
+void CrossTranslationUnitContext::emitCrossTUDiagnostics(
+    const IndexError &IE, SourceLocation Loc) const {
   switch (IE.getCode()) {
   case index_error_code::missing_index_file:
+  case index_error_code::invocation_list_file_not_found:
+    // If the external def-map refers to source files, you must provide an
+    // invocation list file. Otherwise, CTU does not work at all, so you should
+    // check your build and analysis configuration.
     Context.getDiagnostics().Report(Loc, diag::err_ctu_error_opening)
         << IE.getFileName();
     return;
+
   case index_error_code::invalid_index_format:
     Context.getDiagnostics().Report(Loc, diag::err_extdefmap_parsing)
         << IE.getFileName() << IE.getLineNum();
     return;
+
   case index_error_code::multiple_definitions:
     Context.getDiagnostics().Report(Loc, diag::err_multiple_def_index)
         << IE.getLineNum();
     return;
+
   case index_error_code::triple_mismatch:
     Context.getDiagnostics().Report(Loc, diag::warn_ctu_incompat_triple)
-        << IE.getFileName() << IE.getTripleToName() << IE.getTripleFromName();
+        << IE.getFileName() << IE.getConfigToName() << IE.getConfigFromName();
     return;
-  case index_error_code::success:
-    llvm_unreachable("There should not be a success error. This case should "
-                     "have been handled by the caller.");
-    return;
-  case index_error_code::unspecified:
+
   case index_error_code::missing_definition:
+    // Ignore missing definitions because it is very common to have some symbols
+    // defined outside of the analysis scope: they may be defined in 3-rd party
+    // and standard libraries, generated code, and files excluded from the
+    // analysis.
+    // Even ignoring it with Ignored diagnostic might generate too much traffic.
+    return;
+
   case index_error_code::failed_import:
-  case index_error_code::failed_to_get_external_ast:
+  case index_error_code::unspecified:
+    // Not clear what happened exactly, but the outcome is a missing definition
+    // This is not a big deal, and is expected since ASTImporter is incomplete.
+    Context.getDiagnostics().Report(Loc, diag::warn_ctu_import_failure)
+        << Category->message(static_cast<int>(IE.getCode()));
+    return;
----------------
necto wrote:

It wasn't completely clear to me: Do you think I can do something about it in this PR?

https://github.com/llvm/llvm-project/pull/189064