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[lldb][DWARFASTParserClang] Eagerly search definitions for Objective-…
…C classes This patch essentially reverts the definition DIE delay changes (in llvm#98361) for Objective-C. The problem we've been seeing is as follows: 1. An Objetive-C class extension is represented in DWARF as: ``` DW_TAG_structure_type DW_AT_declaration (true) DW_AT_name ("ExtendedClass") DW_TAG_subprogram DW_AT_name ("extensionMethod") ... ``` I.e., it is a forward declaration of the extended class, but that forward declaration has children methods. 2. When we set a breakpoint in one of those methods we parse the subprogram DIE and try to create an `ObjCMethodDecl` for it (and attach it to the context). 3. When parsing the subprogram DIE, we first try to complete the DeclContext. Because `ExtendedClass` is only a forward declaration and we don't try to fetch the definition DIE eagerly anymore, LLDB has no idea that we're dealing with an Objective-C type. So it goes ahead and constructs it as a `CXXRecordDecl`. This confuses `DWARFASTParserClang::ParseObjCMethod` because it expects the context to be an `clang::ObjCObjectOrInterfaceType`. So it bails and we end up crashing because we try to attach a `FunctionDecl` to an incomplete `CXXRecordDecl` (which wasn't even forcefully completed). Since there's no good way to tell whether a forward declaration is an Objective-C type, the only solution I can really see here is to eagerly fetch the definition for Objective-C types.
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lldb/test/Shell/SymbolFile/DWARF/objc-gmodules-class-extension.test
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| # REQUIRES: system-darwin | ||
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| # Test that we can set a breakpoint in a method of a class extension. | ||
| # This requires us to parse the method into an AST type, and the context | ||
| # too (which in DWARF is just a forward declaration). | ||
| # | ||
| # RUN: split-file %s %t | ||
| # RUN: %clangxx_host %t/lib.m -c -g -gmodules -fmodules -o %t/lib.o | ||
| # RUN: %clangxx_host %t/main.m -g -gmodules -fmodules %t/lib.o -o %t/a.out -framework Foundation | ||
| # | ||
| # RUN: %lldb %t/a.out -o "breakpoint set -f lib.m -l 6" -o exit | FileCheck %s | ||
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| # CHECK: (lldb) breakpoint set -f lib.m -l 6 | ||
| # CHECK: Breakpoint 1: where = a.out`-[NSObject(Foo) func] | ||
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| #--- main.m | ||
| int main() { | ||
| return 0; | ||
| } | ||
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| #--- lib.m | ||
| #import <Foundation/Foundation.h> | ||
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| @implementation NSObject (Foo) | ||
| - (NSError *)func { | ||
| NSLog(@"Hello, World!"); | ||
| return 0; | ||
| } | ||
| @end | ||
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| NSObject * func() { | ||
| return 0; | ||
| } |