Resolve native thread ID through SafeAccess

[jbachorik]

What does this PR do?:
It changes the way the native thread id is resolved in the JVMTI based wallclock sampler.

Motivation:
The thread may disappear between having been selected and sampled, or even during preparation to sample.
Since we need to access internal VM structure to retrieve the native thread ID, it may lead to segfault.
Hence, wrapping in SafeAccess will make this, well, safe.

For Datadog employees:

• If this PR touches code that signs or publishes builds or packages, or handles
  credentials of any kind, I've requested a review from @DataDog/security-design-and-guidance.
• This PR doesn't touch any of that.
• JIRA: PROF-11103

Unsure? Have a question? Request a review!

[github-actions]

🔧 Report generated by pr-comment-scanbuild

Scan-Build Report

User:	runner@fv-az1440-974
Working Directory:	/home/runner/work/java-profiler/java-profiler/ddprof-lib/src/test/make
Command Line:	make -j4 clean all
Clang Version:	Ubuntu clang version 18.1.3 (1ubuntu1)
Date:	Thu Jan 9 20:34:31 2025

Bug Summary

Bug Type	Quantity	Display?
All Bugs	5
Logic error
Dereference of null pointer	3
Suspicious operation
Bitwise shift	1
Unused code
Dead nested assignment	1

Reports

Bug Group	Bug Type ▾	File	Function/Method	Line	Path Length
Suspicious operation	Bitwise shift	vmStructs.cpp	find	872	16
Unused code	Dead nested assignment	vmStructs.cpp	checkNativeBinding	977	1
Logic error	Dereference of null pointer	safeAccess.h	load	33	18
Logic error	Dereference of null pointer	symbols_linux.h	ElfParser	129	28
Logic error	Dereference of null pointer	flightRecorder.cpp	flush	1511	8

[github-actions]

🔧 Report generated by pr-comment-cppcheck

CppCheck Report

Warnings (6)

• The class 'RecordingBuffer' defines member function with name 'flushIfNeeded' also defined in its parent class 'Buffer'.
• Obsolete function 'alloca' called.
• Member variable 'ScopeDesc::_stream' is not initialized in the constructor.
• Member variable 'ScopeDesc::_method_offset' is not initialized in the constructor.
• Member variable 'ScopeDesc::_bci' is not initialized in the constructor.
• Member variable 'ElfParser::_vaddr_diff' is not initialized in the constructor.

Style Violations (405)

• Class 'Arguments' has a constructor with 1 argument that is not explicit.
• struct member 'Multiplier::symbol' is never used.
• struct member 'Multiplier::multiplier' is never used.
• class member 'Error::OK' is never used.
• Class 'AsyncSampleMutex' has a constructor with 1 argument that is not explicit.
• The class 'NativeFunc' does not declare a constructor although it has private member variables which likely require initialization.
• Class 'SpinLock' has a constructor with 1 argument that is not explicit.
• Local variable 'count' shadows outer function
• Local variable 'jni' shadows outer function
• Local variable 'size' shadows outer function
• Local variable 'prev' shadows outer function
• Variable 'cb1' can be declared as pointer to const
• Variable 'cb2' can be declared as pointer to const
• Variable 'keys' can be declared as pointer to const
• Parameter 'frames' can be declared as pointer to const
• Parameter 'frames' can be declared as pointer to const
• Variable 'keys' can be declared as pointer to const
• struct member 'CallTrace::truncated' is never used.
• struct member 'CallTrace::num_frames' is never used.
• class member 'CallTraceStorage::_current_table' is never used.
• class member 'CallTraceStorage::_overflow' is never used.
• class member 'CallTraceStorage::_lock' is never used.
• Local variable 'i' shadows outer variable
• Parameter 'prefixes' can be declared as reference to const
• Variable 'fd1' can be declared as pointer to const
• Variable 'fd2' can be declared as pointer to const
• Parameter 'name' can be declared as pointer to const
• Consider using std::transform algorithm instead of a raw loop.
• struct member 'Tag::value' is never used.
• class member 'Context::spanId' is never used.
• class member 'Context::rootSpanId' is never used.
• class member 'Context::checksum' is never used.
• struct member 'ContextPage::capacity' is never used.
• struct member 'ContextPage::storage' is never used.
• class member 'Contexts::_max_pages' is never used.
• class member 'Contexts::_pages' is never used.
• The function 'check' overrides a function in a base class but is not marked with a 'override' specifier.
• The function 'start' overrides a function in a base class but is not marked with a 'override' specifier.
• class member 'Shims::_tid_setter_ref' is never used.
• Class 'Dictionary' has a constructor with 1 argument that is not explicit.
• struct member 'DictRow::keys' is never used.
• struct member 'DictRow::next' is never used.
• Operator '|' with one operand equal to zero is redundant.
• Operator '|' with one operand equal to zero is redundant.
• Local variable 'table' shadows outer function
• Local variable 'pc_off' shadows outer variable
• Variable 'table' can be declared as pointer to const
• struct member 'FrameDesc::cfa' is never used.
• struct member 'FrameDesc::fp_off' is never used.
• struct member 'FrameDesc::pc_off' is never used.
• struct member 'FrameDesc::empty_frame' is never used.
• struct member 'FrameDesc::default_frame' is never used.
• class member 'DwarfParser::_name' is never used.
• class member 'DwarfParser::_image_base' is never used.
• class member 'DwarfParser::_capacity' is never used.
• class member 'DwarfParser::_prev' is never used.
• class member 'DwarfParser::_code_align' is never used.
• class member 'DwarfParser::_data_align' is never used.
• Class 'WallClockEpochEvent' has a constructor with 1 argument that is not explicit.
• class member 'LockEvent::_start_time' is never used.
• class member 'LockEvent::_end_time' is never used.
• class member 'LockEvent::_address' is never used.
• class member 'LockEvent::_timeout' is never used.
• class member 'ObjectLivenessEvent::_alloc' is never used.
• class member 'ObjectLivenessEvent::_skipped' is never used.
• class member 'ObjectLivenessEvent::_start_time' is never used.
• class member 'ObjectLivenessEvent::_age' is never used.
• class member 'ObjectLivenessEvent::_ctx' is never used.
• struct member 'QueueTimeEvent::_start' is never used.
• struct member 'QueueTimeEvent::_end' is never used.
• struct member 'QueueTimeEvent::_task' is never used.
• struct member 'QueueTimeEvent::_scheduler' is never used.
• struct member 'QueueTimeEvent::_origin' is never used.
• The class 'VirtualSpaceSummary' does not declare a constructor although it has private member variables which likely require initialization.
• The class 'GCHeapSummary' does not declare a constructor although it has private member variables which likely require initialization.
• The class 'CollectedHeap' does not declare a constructor although it has private member variables which likely require initialization.
• Class 'Element' has a constructor with 1 argument that is not explicit.
• Class 'NoField' has a constructor with 1 argument that is not explicit.
• Class 'MutexLocker' has a constructor with 1 argument that is not explicit.
• Class 'MethodList' has a constructor with 1 argument that is not explicit.
• Class 'ScopeDesc' has a constructor with 1 argument that is not explicit.
• The function 'is_nofield' overrides a function in a base class but is not marked with a 'override' specifier.
• The function 'check' overrides a function in a base class but is not marked with a 'override' specifier.
• The function 'start' overrides a function in a base class but is not marked with a 'override' specifier.
• The function 'stop' overrides a function in a base class but is not marked with a 'override' specifier.
• The function 'interval' overrides a function in a base class but is not marked with a 'override' specifier.
• Condition 'enabled()' is always false
• Condition 'usage._maxSize==-1' is always false
• Condition 'counters' is always false
• Condition 'i<names.size()' is always false
• Condition '!TSC::initialized()' is always false
• The scope of the variable 'class_name_id' can be reduced.
• The scope of the variable 'method_name_id' can be reduced.
• The scope of the variable 'method_sig_id' can be reduced.
• Local variable 'start' shadows outer function
• Parameter 'frame' can be declared as reference to const
• Variable 'strings' can be declared as reference to const
• Parameter 'args' can be declared as reference to const
• Parameter 'constants' can be declared as reference to const
• Parameter 'ptr' can be declared as pointer to const. However it seems that 'load32' is a callback function, if 'ptr' is declared with const you might also need to cast function pointer(s).
• Variable 'methods' can be declared as pointer to const
• Parameter 'func' can be declared as pointer to const
• Variable 'counters' can be declared as pointer to const
• Parameter 'event' can be declared as pointer to const
• Parameter 'event' can be declared as pointer to const
• Parameter 'event' can be declared as pointer to const
• Parameter 'event' can be declared as pointer to const
• Parameter 'event' can be declared as pointer to const
• Parameter 'event' can be declared as pointer to const
• Parameter 'event' can be declared as pointer to const
• Parameter 'event' can be declared as pointer to const
• Variable 'class_name_id' is assigned a value that is never used.
• Variable 'method_name_id' is assigned a value that is never used.
• Variable 'method_sig_id' is assigned a value that is never used.
• Parameter 'ptr' can be declared as pointer to const
• struct member 'CpuTime::real' is never used.
• struct member 'CpuTime::user' is never used.
• struct member 'CpuTime::system' is never used.
• struct member 'CpuTimes::proc' is never used.
• struct member 'CpuTimes::total' is never used.
• class member 'Recording::_agent_properties' is never used.
• class member 'Recording::_jvm_args' is never used.
• class member 'Recording::_jvm_flags' is never used.
• class member 'Recording::_java_command' is never used.
• class member 'Recording::_fd' is never used.
• class member 'Recording::_start_time' is never used.
• class member 'Recording::_recording_start_time' is never used.
• class member 'Recording::_start_ticks' is never used.
• class member 'Recording::_recording_start_ticks' is never used.
• class member 'Recording::_stop_time' is never used.
• class member 'Recording::_stop_ticks' is never used.
• class member 'Recording::_base_id' is never used.
• class member 'Recording::_bytes_written' is never used.
• class member 'Recording::_tid' is never used.
• class member 'Recording::_available_processors' is never used.
• class member 'Recording::_recorded_lib_count' is never used.
• class member 'Recording::_cpu_monitor_enabled' is never used.
• class member 'Recording::_last_times' is never used.
• class member 'FlightRecorder::_filename' is never used.
• The function 'name' overrides a function in a base class but is not marked with a 'override' specifier.
• The function 'interval' overrides a function in a base class but is not marked with a 'override' specifier.
• The function 'check' overrides a function in a base class but is not marked with a 'override' specifier.
• The function 'start' overrides a function in a base class but is not marked with a 'override' specifier.
• The function 'stop' overrides a function in a base class but is not marked with a 'override' specifier.
• The function 'enableEvents' overrides a function in a base class but is not marked with a 'override' specifier.
• class member 'ITimer::_cstack' is never used.
• struct member 'jvmtiFrameInfoExtended::native_frame_address' is never used.
• struct member 'jvmtiStackInfoExtended::frame_buffer' is never used.
• class member 'J9Ext::InstrumentableObjectAlloc_id' is never used.
• The class 'J9WallClock' does not declare a constructor although it has private member variables which likely require initialization.
• The function 'name' overrides a function in a base class but is not marked with a 'override' specifier.
• The function 'interval' overrides a function in a base class but is not marked with a 'override' specifier.
• The function 'start' overrides a function in a base class but is not marked with a 'override' specifier.
• The function 'stop' overrides a function in a base class but is not marked with a 'override' specifier.
• The function 'enableEvents' overrides a function in a base class but is not marked with a 'override' specifier.
• class member 'J9WallClock::_max_stack_depth' is never used.
• class member 'J9WallClock::_running' is never used.
• Class 'ReservoirSampler' has a constructor with 1 argument that is not explicit.
• The function 'name' overrides a function in a base class but is not marked with a 'override' specifier.
• The function 'interval' overrides a function in a base class but is not marked with a 'override' specifier.
• The function 'enableEvents' overrides a function in a base class but is not marked with a 'override' specifier.
• The function 'start' overrides a function in a base class but is not marked with a 'override' specifier.
• The function 'stop' overrides a function in a base class but is not marked with a 'override' specifier.
• Variable 'value' can be declared as pointer to const
• Variable 'size' is assigned a value that is never used.
• class member 'JfrMetadata::_initialized' is never used.
• class member 'JVM::_is_readable_pointer_resolved' is never used.
• class member 'JVM::_is_readable_pointer' is never used.
• class member 'VirtualSpaceSummary::_committed_end' is never used.
• class member 'GCHeapSummary::vptr' is never used.
• class member 'CollectedHeap::vptr' is never used.
• class member 'CollectedHeap::_gc_heap_log' is never used.
• class member 'CollectedHeap::_capacity_at_last_gc' is never used.
• class member 'CollectedHeap::_used_at_last_gc' is never used.
• struct member 'Chunk::prev' is never used.
• struct member 'Chunk::offs' is never used.
• struct member 'Chunk::_padding' is never used.
• class member 'LinearAllocator::_chunk_size' is never used.
• class member 'LinearAllocator::_tail' is never used.
• class member 'LinearAllocator::_reserve' is never used.
• Local variable 'start' shadows outer function
• Local variable 'start' shadows outer function
• Parameter 'args' can be declared as reference to const
• Parameter 'event' can be declared as reference to const
• Parameter 'frames' can be declared as pointer to const
• Unused variable: kept_classes
• struct member 'TrackingEntry::alloc' is never used.
• struct member 'TrackingEntry::skipped' is never used.
• struct member 'TrackingEntry::frames' is never used.
• struct member 'TrackingEntry::ctx' is never used.
• class member 'LivenessTracker::MAX_TRACKING_TABLE_SIZE' is never used.
• class member 'LivenessTracker::MIN_SAMPLING_INTERVAL' is never used.
• class member 'LivenessTracker::_table_lock' is never used.
• Condition 'level>=_level' is always true
• Parameter 'args' can be declared as reference to const
• class member 'Log::_file' is never used.
• class member 'Log::LEVEL_NAME' is never used.
• class member 'ObjectSampler::CONFIG_UPDATE_CHECK_PERIOD_SECS' is never used.
• class member 'JitWriteProtection::_prev' is never used.
• class member 'JitWriteProtection::_restore' is never used.
• class member 'OS::page_size' is never used.
• class member 'OS::page_mask' is never used.
• The function 'rewind' overrides a function in a base class but is not marked with a 'override' specifier.
• The function 'next' overrides a function in a base class but is not marked with a 'override' specifier.
• The function 'size' overrides a function in a base class but is not marked with a 'override' specifier.
• The function 'check' overrides a function in a base class but is not marked with a 'override' specifier.
• The function 'start' overrides a function in a base class but is not marked with a 'override' specifier.
• The function 'enableEvents' overrides a function in a base class but is not marked with a 'override' specifier.
• The function 'registerThread' overrides a function in a base class but is not marked with a 'override' specifier.
• The function 'unregisterThread' overrides a function in a base class but is not marked with a 'override' specifier.
• The function 'interval' overrides a function in a base class but is not marked with a 'override' specifier.
• The function 'enableEvents' overrides a function in a base class but is identical to the overridden function
• The function 'registerThread' overrides a function in a base class but is identical to the overridden function
• The function 'unregisterThread' overrides a function in a base class but is identical to the overridden function
• Condition 'i<PROBE_SP_LIMIT' is always false
• Condition 'event_name==NULL' is always true
• Variable 'sp' can be declared as reference to const
• Variable 'pc' can be declared as reference to const
• Parameter 'args' can be declared as reference to const
• Parameter 'java_ctx' can be declared as pointer to const
• Variable 'error' is assigned a value that is never used.
• Variable 'error' is assigned a value that is never used.
• Variable 'error' is assigned a value that is never used.
• Variable 'error' is assigned a value that is never used.
• Condition 'length>0' is always false
• class member 'Profiler::_signals_initialized' is never used.
• class member 'Profiler::_class_map_lock' is never used.
• class member 'Profiler::_locks' is never used.
• Condition 'strcmp(name,"forward_copy_longs")==0' is always false
• Condition 'strcmp(name,"backward_copy_longs")==0' is always false
• Variable 'ip' can be declared as pointer to const
• Parameter 'ip' can be declared as pointer to const
• Variable 'ip' can be declared as pointer to const
• Parameter 'pc' can be declared as pointer to const
• Unused private function: 'StackFrame::withinCurrentStack'
• Variable 'ip' can be declared as pointer to const
• Parameter 'entry' can be declared as pointer to const
• Variable 'ip' can be declared as pointer to const
• Parameter 'pc' can be declared as pointer to const
• Variable 'ip' can be declared as pointer to const
• Variable 'ip' can be declared as pointer to const
• Variable 'entry' can be declared as pointer to const
• Parameter 'pc' can be declared as pointer to const
• Parameter 'sp' can be declared as reference to const
• Variable 'inst' can be declared as pointer to const
• Variable 'inst' can be declared as pointer to const
• Parameter 'pc' can be declared as pointer to const
• Variable 'ip' can be declared as pointer to const
• Parameter 'pc' can be declared as pointer to const
• Local variable 'pc' shadows outer function
• Return value 'ptr>(const void*)-DEAD_ZONE' is always true
• Condition '!inDeadZone(method)' is always false
• Condition '!inDeadZone(method_id)' is always false
• Condition 'inDeadZone(pc)' is always true
• Condition 'inDeadZone(pc)' is always true
• Condition 'is_plausible_interpreter_frame' is always false
• Condition 'inDeadZone(pc)' is always true
• The comparison 'EMPTY_FRAME_SIZE > 0' is always false.
• The comparison 'EMPTY_FRAME_SIZE > 0' is always false.
• The scope of the variable 'prev_sp' can be reduced.
• Local variable 'frame' shadows outer variable
• The comparison 'EMPTY_FRAME_SIZE > 0' is always false.
• The comparison 'EMPTY_FRAME_SIZE > 0' is always false.
• Class 'SymbolDesc' has a constructor with 1 argument that is not explicit.
• Class 'MemoryMapDesc' has a constructor with 1 argument that is not explicit.
• Local variable 'section' shadows outer function
• Local variable 'section' shadows outer function
• Local variable 'section' shadows outer function
• Variable 'ident' can be declared as pointer to const
• Parameter 'section' can be declared as pointer to const
• Variable 'checked' can be declared as pointer to const
• Variable 'pheader' can be declared as pointer to const
• Variable 'sym' can be declared as pointer to const
• Variable 'sym' can be declared as pointer to const
• Variable 'chain' can be declared as pointer to const
• Variable 'plt' can be declared as pointer to const
• Variable 'note' can be declared as pointer to const
• Variable 'sym' can be declared as pointer to const
• Variable 'sym' can be declared as pointer to const
• Local variable 'tid' shadows outer function
• Local variable 'tid' shadows outer function
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• class member 'ProfiledThread::_buffer' is never used.
• Local variable 'word' shadows outer function
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• class member 'ThreadInfo::_thread_names' is never used.
• class member 'ThreadInfo::_thread_ids' is never used.
• class member 'Trap::_page_start' is never used.
• Local variable 'frequency' shadows outer function
• Local variable 'flag_addr' shadows outer variable
• Variable 'idx' can be declared as pointer to const
• Parameter 'prop_value' can be declared as pointer to const
• Variable 'flag_addr' can be declared as pointer to const
• Parameter 'options' can be declared as pointer to const
• struct member 'ASGCT_CallTrace::env' is never used.
• struct member 'ASGCT_CallTrace::frames' is never used.
• struct member 'VMManagement::unused' is never used.
• struct member 'JVMTIFunctions::unused1' is never used.
• struct member 'JVMTIFunctions::unused2' is never used.
• struct member 'JavaFullVersion::major' is never used.
• struct member 'JavaFullVersion::update' is never used.
• class member 'VM::_can_intercept_binding' is never used.
• class member 'VM::_libjvm' is never used.
• class member 'VM::_libjava' is never used.
• class member 'VM::_asyncGetCallTrace' is never used.
• The scope of the variable 'delayedCounter' can be reduced.
• Local variable 'type' shadows outer function
• Parameter 'ptr' can be declared as pointer to const. However it seems that 'load32' is a callback function, if 'ptr' is declared with const you might also need to cast function pointer(s).
• Variable 'code_heap_array' can be declared as pointer to const
• Variable 'blob' can be declared as pointer to const
• Parameter 'vm_thread' can be declared as pointer to const
• Variable 'segmap' can be declared as pointer to const
• Variable 'type_name' can be declared as pointer to const
• Variable 'pcd_end' can be declared as pointer to const
• Consider using std::any_of, std::all_of, std::none_of, or std::accumulate algorithm instead of a raw loop.
• Variable 'error' is assigned a value that is never used.
• class member 'VMStructs::_has_native_thread_id' is never used.
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• class member 'VMStructs::_scopes_pcs_offset' is never used.
• class member 'VMStructs::_constmethod_constants_offset' is never used.
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• class member 'VMStructs::_array_data_offset' is never used.
• class member 'VMStructs::_code_heap_segmap_offset' is never used.
• class member 'VMStructs::_code_heap_segment_shift' is never used.
• class member 'VMStructs::_heap_block_used_offset' is never used.
• class member 'VMStructs::_vs_low_bound_offset' is never used.
• class member 'VMStructs::_vs_high_bound_offset' is never used.
• class member 'VMStructs::_flag_type_offset' is never used.
• class member 'VMStructs::_flags_addr' is never used.
• class member 'VMStructs::_flag_count' is never used.
• class member 'VMStructs::_flag_size' is never used.
• class member 'VMStructs::_code_heap_low_addr' is never used.
• class member 'VMStructs::_code_heap_high_addr' is never used.
• class member 'VMStructs::_klass_offset_addr' is never used.
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• class member 'VMStructs::_narrow_klass_base' is never used.
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• class member 'VMStructs::_narrow_klass_shift' is never used.
• class member 'VMStructs::_collected_heap' is never used.
• class member 'VMStructs::_collected_heap_reserved_offset' is never used.
• class member 'VMStructs::_region_start_offset' is never used.
• class member 'VMStructs::_region_size_offset' is never used.
• class member 'VMStructs::_markword_klass_shift' is never used.
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• class member 'VMStructs::_unsigned5_base' is never used.
• class member 'VMStructs::_call_stub_return_addr' is never used.
• class member 'VMStructs::_find_flag_func' is never used.
• class member 'VMStructs::_is_valid_method_func' is never used.
• class member 'HeapUsage::is_jmx_attempted' is never used.
• class member 'PcDesc::_pc' is never used.
• class member 'PcDesc::_scope_offset' is never used.
• class member 'PcDesc::_obj_offset' is never used.
• class member 'PcDesc::_flags' is never used.
• Condition 'vm_thread' is always true
• Local variable 'interval' shadows outer function
• Variable 'context' can be declared as reference to const
• struct member 'ThreadEntry::native' is never used.
• The function 'patchImport' is never used.
• The function 'getCounter' is never used.
• The function 'supported' is never used.
• The function 'updateCounter' is never used.
• The function 'deallocateLineNumberTable' is never used.
• The function 'copyTo' is never used.
• The function 'cpuMonitorCycle' is never used.
• The function 'appendRecording' is never used.
• The function 'writeListSetting' is never used.
• The function 'units' is never used.
• The function 'can_use_ASGCT' is never used.
• The function 'is_jmethodid_safe' is never used.
• The function 'GetJ9vmThread' is never used.
• The function 'is_readable_pointer' is never used.
• The function '_min' is never used.
• The function 'trace' is never used.
• The function 'waitUntil' is never used.
• The function 'notify' is never used.
• The function 'cputime' is never used.
• The function 'ntoh64' is never used.
• The function 'schedPolicy' is never used.
• The function 'fileSize' is never used.
• The function 'getJavaTraceJvmti' is never used.
• The function 'getJavaTraceInternal' is never used.
• The function 'flushJfr' is never used.
• The function 'restart' is never used.
• The function 'arg0' is never used.
• The function 'arg2' is never used.
• The function 'jarg0' is never used.
• The function 'ret' is never used.
• The function 'clearParsingCaches' is never used.
• The function 'isDeepCrashHandler' is never used.
• The function 'getThreadId' is never used.
• The function 'assign' is never used.
• The function 'covers' is never used.
• The function 'install' is never used.
• The function 'uninstall' is never used.
• The function 'loaded' is never used.
• The function 'hasClassNames' is never used.
• The function 'hasCompilerStructs' is never used.
• The function 'body' is never used.
• The function 'fromHandle' is never used.
• The function 'fromMethodID' is never used.
• The function 'isEntryFrame' is never used.
• The function 'inJava' is never used.
• The function 'lastJavaFP' is never used.
• The function 'compiledMethod' is never used.

[jbachorik]

Closed in favour of #168