Author: jeffreytan81 Date: 2023-10-17T17:26:05-07:00 New Revision: 659a48f25a96b7072b44d372c47385a2608f8671
URL: https://github.com/llvm/llvm-project/commit/659a48f25a96b7072b44d372c47385a2608f8671 DIFF: https://github.com/llvm/llvm-project/commit/659a48f25a96b7072b44d372c47385a2608f8671.diff LOG: Detect against invalid variant index for LibStdC++ std::variant data formatters (#69253) https://github.com/llvm/llvm-project/pull/68012/files added new data formatters for LibStdC++ std::variant. However, this formatter can crash if std::variant's index field has invalid value (exceeds the number of template arguments). This can happen if the current IP stops at a place std::variant is not initialized yet. This patch fixes the crash by ensuring the index is a valid value. --------- Co-authored-by: jeffreytan81 <jeffrey...@fb.com> Added: Modified: lldb/examples/synthetic/gnu_libstdcpp.py lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp lldb/test/API/functionalities/data-formatter/data-formatter-stl/libstdcpp/variant/TestDataFormatterLibStdcxxVariant.py Removed: ################################################################################ diff --git a/lldb/examples/synthetic/gnu_libstdcpp.py b/lldb/examples/synthetic/gnu_libstdcpp.py index 29c926167fb440c..f778065aaca3771 100644 --- a/lldb/examples/synthetic/gnu_libstdcpp.py +++ b/lldb/examples/synthetic/gnu_libstdcpp.py @@ -914,6 +914,11 @@ def get_variant_npos_value(index_byte_size): if index == npos_value: return " No Value" + # Invalid index can happen when the variant is not initialized yet. + template_arg_count = data_obj.GetType().GetNumberOfTemplateArguments() + if index >= template_arg_count: + return " <Invalid>" + active_type = data_obj.GetType().GetTemplateArgumentType(index) return f" Active Type = {active_type.GetDisplayTypeName()} " diff --git a/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp b/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp index f1353db2631ddc6..0b8edbb75eb9aee 100644 --- a/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp +++ b/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp @@ -7182,6 +7182,9 @@ GetNthTemplateArgument(const clang::ClassTemplateSpecializationDecl *decl, // Note that 'idx' counts from the beginning of all template arguments // (including the ones preceding the parameter pack). const auto &pack = args[last_idx]; + if (idx >= pack.pack_size()) + return nullptr; + const size_t pack_idx = idx - last_idx; assert(pack_idx < pack.pack_size() && "parameter pack index out-of-bounds"); return &pack.pack_elements()[pack_idx]; diff --git a/lldb/test/API/functionalities/data-formatter/data-formatter-stl/libstdcpp/variant/TestDataFormatterLibStdcxxVariant.py b/lldb/test/API/functionalities/data-formatter/data-formatter-stl/libstdcpp/variant/TestDataFormatterLibStdcxxVariant.py index 96a9c8d30c45b00..ba1641888b6f30f 100644 --- a/lldb/test/API/functionalities/data-formatter/data-formatter-stl/libstdcpp/variant/TestDataFormatterLibStdcxxVariant.py +++ b/lldb/test/API/functionalities/data-formatter/data-formatter-stl/libstdcpp/variant/TestDataFormatterLibStdcxxVariant.py @@ -71,3 +71,29 @@ def test_with_run_command(self): substrs=["v_many_types_no_value = No Value"], ) """ + + @add_test_categories(["libstdcxx"]) + def test_invalid_variant_index(self): + """Test LibStdC++ data formatter for std::variant with invalid index.""" + self.build() + + (self.target, self.process, thread, bkpt) = lldbutil.run_to_source_breakpoint( + self, "// break here", lldb.SBFileSpec("main.cpp", False) + ) + + lldbutil.continue_to_breakpoint(self.process, bkpt) + + self.expect( + "frame variable v1", + substrs=["v1 = Active Type = int {", "Value = 12", "}"], + ) + + var_v1 = thread.frames[0].FindVariable("v1") + var_v1_raw_obj = var_v1.GetNonSyntheticValue() + index_obj = var_v1_raw_obj.GetChildMemberWithName("_M_index") + self.assertTrue(index_obj and index_obj.IsValid()) + + INVALID_INDEX = "100" + index_obj.SetValueFromCString(INVALID_INDEX) + + self.expect("frame variable v1", substrs=["v1 = <Invalid>"]) _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
