Author: Pavel Labath Date: 2025-05-02T14:20:14+02:00 New Revision: 26a1366380796f95f308faab5010b019c4b75b10
URL: https://github.com/llvm/llvm-project/commit/26a1366380796f95f308faab5010b019c4b75b10 DIFF: https://github.com/llvm/llvm-project/commit/26a1366380796f95f308faab5010b019c4b75b10.diff LOG: [lldb] Fix dynamic type resolution for types parsed from declarations (#137974) This fixes a regression caused by us starting to parse types from declarations. The code in TypeSystemClang was assuming that the value held in ClangASTMetadata was authoritative, but this isn't (and cannot) be the case when the type is parsed from a forward-declaration. For the fix, I add a new "don't know" state to ClangASTMetadata, and make sure DWARFASTParserClang sets it only when it encounters a forward declaration. In this case, the type system will fall back to completing the type. This does mean that we will be completing more types than before, but I'm hoping this will offset by the fact that we don't search for definition DIEs eagerly. In particular, I don't expect it to make a difference in -fstandalone-debug scenarios, since types will nearly always be present as definitions. To avoid this cost, we'd need to create some sort of a back channel to query the DWARFASTParser about the dynamicness of the type without actually completing it. I'd like to avoid that if it is not necessary. Added: lldb/test/API/lang/cpp/dynamic-value/forward-a.cpp Modified: lldb/source/Plugins/ExpressionParser/Clang/ClangASTMetadata.cpp lldb/source/Plugins/ExpressionParser/Clang/ClangASTMetadata.h lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp lldb/test/API/lang/cpp/dynamic-value/Makefile lldb/test/API/lang/cpp/dynamic-value/TestDynamicValue.py lldb/test/API/lang/cpp/dynamic-value/a.h lldb/test/API/lang/cpp/dynamic-value/pass-to-base.cpp Removed: ################################################################################ diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangASTMetadata.cpp b/lldb/source/Plugins/ExpressionParser/Clang/ClangASTMetadata.cpp index 42933c78b0277..2c5dacb60a9b8 100644 --- a/lldb/source/Plugins/ExpressionParser/Clang/ClangASTMetadata.cpp +++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangASTMetadata.cpp @@ -11,6 +11,22 @@ using namespace lldb_private; +std::optional<bool> ClangASTMetadata::GetIsDynamicCXXType() const { + switch (m_is_dynamic_cxx) { + case 0: + return std::nullopt; + case 1: + return false; + case 2: + return true; + } + llvm_unreachable("Invalid m_is_dynamic_cxx value"); +} + +void ClangASTMetadata::SetIsDynamicCXXType(std::optional<bool> b) { + m_is_dynamic_cxx = b ? *b + 1 : 0; +} + void ClangASTMetadata::Dump(Stream *s) { lldb::user_id_t uid = GetUserID(); diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangASTMetadata.h b/lldb/source/Plugins/ExpressionParser/Clang/ClangASTMetadata.h index d3bcde2ced799..ecaa2e0ddf97c 100644 --- a/lldb/source/Plugins/ExpressionParser/Clang/ClangASTMetadata.h +++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangASTMetadata.h @@ -12,6 +12,7 @@ #include "lldb/Core/dwarf.h" #include "lldb/lldb-defines.h" #include "lldb/lldb-enumerations.h" +#include "lldb/lldb-private-enumerations.h" namespace lldb_private { @@ -19,12 +20,14 @@ class ClangASTMetadata { public: ClangASTMetadata() : m_user_id(0), m_union_is_user_id(false), m_union_is_isa_ptr(false), - m_has_object_ptr(false), m_is_self(false), m_is_dynamic_cxx(true), - m_is_forcefully_completed(false) {} + m_has_object_ptr(false), m_is_self(false), + m_is_forcefully_completed(false) { + SetIsDynamicCXXType(std::nullopt); + } - bool GetIsDynamicCXXType() const { return m_is_dynamic_cxx; } + std::optional<bool> GetIsDynamicCXXType() const; - void SetIsDynamicCXXType(bool b) { m_is_dynamic_cxx = b; } + void SetIsDynamicCXXType(std::optional<bool> b); void SetUserID(lldb::user_id_t user_id) { m_user_id = user_id; @@ -101,8 +104,8 @@ class ClangASTMetadata { uint64_t m_isa_ptr; }; - bool m_union_is_user_id : 1, m_union_is_isa_ptr : 1, m_has_object_ptr : 1, - m_is_self : 1, m_is_dynamic_cxx : 1, m_is_forcefully_completed : 1; + unsigned m_union_is_user_id : 1, m_union_is_isa_ptr : 1, m_has_object_ptr : 1, + m_is_self : 1, m_is_dynamic_cxx : 2, m_is_forcefully_completed : 1; }; } // namespace lldb_private diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp index f22fcbab557a0..a3e809f44ed23 100644 --- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp +++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp @@ -1837,7 +1837,8 @@ DWARFASTParserClang::ParseStructureLikeDIE(const SymbolContext &sc, ClangASTMetadata metadata; metadata.SetUserID(die.GetID()); - metadata.SetIsDynamicCXXType(dwarf->ClassOrStructIsVirtual(die)); + if (!attrs.is_forward_declaration) + metadata.SetIsDynamicCXXType(dwarf->ClassOrStructIsVirtual(die)); TypeSystemClang::TemplateParameterInfos template_param_infos; if (ParseTemplateParameterInfos(die, template_param_infos)) { diff --git a/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp b/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp index cb0ecd6ebd406..1a2b3d4133e51 100644 --- a/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp +++ b/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp @@ -3657,13 +3657,17 @@ bool TypeSystemClang::IsPossibleDynamicType(lldb::opaque_compiler_type_t type, bool success; if (cxx_record_decl->isCompleteDefinition()) success = cxx_record_decl->isDynamicClass(); - else if (std::optional<ClangASTMetadata> metadata = - GetMetadata(cxx_record_decl)) - success = metadata->GetIsDynamicCXXType(); - else if (GetType(pointee_qual_type).GetCompleteType()) - success = cxx_record_decl->isDynamicClass(); - else - success = false; + else { + std::optional<ClangASTMetadata> metadata = GetMetadata(cxx_record_decl); + std::optional<bool> is_dynamic = + metadata ? metadata->GetIsDynamicCXXType() : std::nullopt; + if (is_dynamic) + success = *is_dynamic; + else if (GetType(pointee_qual_type).GetCompleteType()) + success = cxx_record_decl->isDynamicClass(); + else + success = false; + } if (success) set_dynamic_pointee_type(pointee_qual_type); diff --git a/lldb/test/API/lang/cpp/dynamic-value/Makefile b/lldb/test/API/lang/cpp/dynamic-value/Makefile index ce91dc63f473f..24346ccfae510 100644 --- a/lldb/test/API/lang/cpp/dynamic-value/Makefile +++ b/lldb/test/API/lang/cpp/dynamic-value/Makefile @@ -1,3 +1,3 @@ -CXX_SOURCES := pass-to-base.cpp anonymous-b.cpp +CXX_SOURCES := pass-to-base.cpp anonymous-b.cpp forward-a.cpp include Makefile.rules diff --git a/lldb/test/API/lang/cpp/dynamic-value/TestDynamicValue.py b/lldb/test/API/lang/cpp/dynamic-value/TestDynamicValue.py index 32ef009279713..3952b88a6c28e 100644 --- a/lldb/test/API/lang/cpp/dynamic-value/TestDynamicValue.py +++ b/lldb/test/API/lang/cpp/dynamic-value/TestDynamicValue.py @@ -266,3 +266,15 @@ def examine_value_object_of_this_ptr( contained_b_static_addr = int(contained_b_static.GetValue(), 16) self.assertLess(contained_b_addr, contained_b_static_addr) + + @no_debug_info_test + def test_from_forward_decl(self): + """Test fetching C++ dynamic values forward-declared types. It's + imperative that this is a separate test so that we don't end up parsing + a definition of A from somewhere else.""" + self.build() + lldbutil.run_to_name_breakpoint(self, "take_A") + self.expect( + "frame var -d run-target --ptr-depth=1 --show-types a", + substrs=["(B *) a", "m_b_value = 10"], + ) diff --git a/lldb/test/API/lang/cpp/dynamic-value/a.h b/lldb/test/API/lang/cpp/dynamic-value/a.h index 708cbb79fee5c..c8895ab095d82 100644 --- a/lldb/test/API/lang/cpp/dynamic-value/a.h +++ b/lldb/test/API/lang/cpp/dynamic-value/a.h @@ -22,4 +22,6 @@ class A { A *make_anonymous_B(); +A *take_A(A *a); + #endif diff --git a/lldb/test/API/lang/cpp/dynamic-value/forward-a.cpp b/lldb/test/API/lang/cpp/dynamic-value/forward-a.cpp new file mode 100644 index 0000000000000..8a212d928d5c5 --- /dev/null +++ b/lldb/test/API/lang/cpp/dynamic-value/forward-a.cpp @@ -0,0 +1,3 @@ +class A; + +A *take_A(A *a) { return a; } diff --git a/lldb/test/API/lang/cpp/dynamic-value/pass-to-base.cpp b/lldb/test/API/lang/cpp/dynamic-value/pass-to-base.cpp index be763390cc6f9..9b601084cdc57 100644 --- a/lldb/test/API/lang/cpp/dynamic-value/pass-to-base.cpp +++ b/lldb/test/API/lang/cpp/dynamic-value/pass-to-base.cpp @@ -45,5 +45,7 @@ main (int argc, char **argv) myB.doSomething(*make_anonymous_B()); + take_A(&myB); + return 0; } _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
