[lldb][TypeSystemClang] Avoid accessing definition if none is available #9217
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We've been hitting cases where LLDB marks a decl as `isCompleteDefinition` but no definition was allocated for it. Then when we access a an API in which Clang assumes a definition exists, and dereferences a nullptr. In the specific case that happens when we've incorrectly been keeping track of the `ImportedDecls` in `clang::ASTImporter` (which manifests as trying to `MapImported` on two different destination decls from the same source decl for the same ClangASTImporterDelegate). The more fundmental issue is that we're failing to complete the type properly. But the fix for that is still in-progress. So we're working around the crash by guarding against failed type completion. rdar://133958782
| is_complete = GetType(pointee_qual_type).GetCompleteType(); | ||
| // Make sure completion has actually completed the type. | ||
| is_complete = GetType(pointee_qual_type).GetCompleteType() && | ||
| HasCompleteDefinition(cxx_record_decl); |
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Which action could have changed the result of HasCompleteDefinition(cxx_record_decl) since line 3747?
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In the call to GetCompleteType (which does much more than the name suggests)
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We've been hitting cases where LLDB marks a decl as
isCompleteDefinitionbut no definition was allocated for it. Then when we access a an API in which Clang assumes a definition exists, and dereferences a nullptr. In the specific case that happens when we've incorrectly been keeping track of theImportedDeclsinclang::ASTImporter(which manifests as trying toMapImportedon two different destination decls from the same source decl for the same ClangASTImporterDelegate).The more fundmental issue is that we're failing to complete the type properly. But the fix for that is still in-progress. So we're working around the crash by guarding against failed type completion.
rdar://133958782