Author: Igor Kudrin Date: 2025-05-20T13:50:24-07:00 New Revision: 3f196e029314e3ccb429413a5f38ad241e50f3c5
URL: https://github.com/llvm/llvm-project/commit/3f196e029314e3ccb429413a5f38ad241e50f3c5 DIFF: https://github.com/llvm/llvm-project/commit/3f196e029314e3ccb429413a5f38ad241e50f3c5.diff LOG: [lldb][core] Fix getting summary of a variable pointing to r/o memory (#139196) Motivation example: ``` > lldb -c altmain2.core ... (lldb) var F (const char *) F = 0x0804a000 "" ``` The variable `F` points to a read-only memory page not dumped to the core file, so `Process::ReadMemory()` cannot read the data. The patch switches to `Target::ReadMemory()`, which can read data both from the process memory and the application binary. Added: lldb/test/API/functionalities/postmortem/elf-core/altmain2.core lldb/test/API/functionalities/postmortem/elf-core/altmain2.out Modified: lldb/source/ValueObject/ValueObject.cpp lldb/test/API/functionalities/postmortem/elf-core/TestLinuxCore.py Removed: ################################################################################ diff --git a/lldb/source/ValueObject/ValueObject.cpp b/lldb/source/ValueObject/ValueObject.cpp index 46426ae499be9..487c95ca03a69 100644 --- a/lldb/source/ValueObject/ValueObject.cpp +++ b/lldb/source/ValueObject/ValueObject.cpp @@ -734,11 +734,13 @@ size_t ValueObject::GetPointeeData(DataExtractor &data, uint32_t item_idx, } break; case eAddressTypeLoad: { ExecutionContext exe_ctx(GetExecutionContextRef()); - Process *process = exe_ctx.GetProcessPtr(); - if (process) { + if (Target *target = exe_ctx.GetTargetPtr()) { heap_buf_ptr->SetByteSize(bytes); - size_t bytes_read = process->ReadMemory( - addr + offset, heap_buf_ptr->GetBytes(), bytes, error); + Address target_addr; + target_addr.SetLoadAddress(addr + offset, target); + size_t bytes_read = + target->ReadMemory(target_addr, heap_buf_ptr->GetBytes(), bytes, + error, /*force_live_memory=*/true); if (error.Success() || bytes_read > 0) { data.SetData(data_sp); return bytes_read; diff --git a/lldb/test/API/functionalities/postmortem/elf-core/TestLinuxCore.py b/lldb/test/API/functionalities/postmortem/elf-core/TestLinuxCore.py index a287fd19ba352..a68175dc4e4d7 100644 --- a/lldb/test/API/functionalities/postmortem/elf-core/TestLinuxCore.py +++ b/lldb/test/API/functionalities/postmortem/elf-core/TestLinuxCore.py @@ -977,6 +977,34 @@ def test_get_core_file_api(self): self.assertEqual(process.GetCoreFile().GetFilename(), core_file_name) self.dbg.DeleteTarget(target) + @skipIfLLVMTargetMissing("X86") + def test_read_only_cstring(self): + """ + Test that we can show the summary for a cstring variable that points + to a read-only memory page which is not dumped to a core file. + """ + target = self.dbg.CreateTarget("altmain2.out") + process = target.LoadCore("altmain2.core") + self.assertTrue(process, PROCESS_IS_VALID) + + frame = process.GetSelectedThread().GetFrameAtIndex(0) + self.assertEqual(frame.GetFunctionName(), "_start") + + var = frame.FindVariable("F") + + # The variable points to a read-only segment that is not dumped to + # the core file and thus 'process.ReadCStringFromMemory()' cannot get + # the value. + error = lldb.SBError() + cstr = process.ReadCStringFromMemory(var.GetValueAsUnsigned(), 256, error) + self.assertFailure(error, error_str="core file does not contain 0x804a000") + self.assertEqual(cstr, "") + + # Nevertheless, when getting the summary, the value can be read from the + # application binary. + cstr = var.GetSummary() + self.assertEqual(cstr, '"_start"') + def check_memory_regions(self, process, region_count): region_list = process.GetMemoryRegions() self.assertEqual(region_list.GetSize(), region_count) diff --git a/lldb/test/API/functionalities/postmortem/elf-core/altmain2.core b/lldb/test/API/functionalities/postmortem/elf-core/altmain2.core new file mode 100755 index 0000000000000..b9dd8de08b813 Binary files /dev/null and b/lldb/test/API/functionalities/postmortem/elf-core/altmain2.core diff er diff --git a/lldb/test/API/functionalities/postmortem/elf-core/altmain2.out b/lldb/test/API/functionalities/postmortem/elf-core/altmain2.out new file mode 100755 index 0000000000000..e930c3d8055e1 Binary files /dev/null and b/lldb/test/API/functionalities/postmortem/elf-core/altmain2.out diff er _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
