Pretty Stack Trace library
Table of Contents
The goal of the project is to enable C/C++ developers to get informative stack trace in case of program crash (inside of signal handler). Key feature is to log not only function address/name/line etc but (if DWARF .debug_info section is present) values of function's parameters and variables.
Currently development focused on x86_64 architecture and for Linux OS, but further may be expanded to other architectures and OS if it will be demanded and some people will like to contribute to the project to support this architecture and OS.
As a first stage the goal is to dump only C/C++ base types such as pointer, boolean, integer etc.
Second stage dump composite types such as C structures, C++ classes, arrays etc.
Third stage to dump dereferenced pointers to data types with pointer validation.
Dependencies
Currently library mostly depends on libunwind library which used to unwind function's stack frames from stack in signal handler, and libdw library which gives access to DWARF information of executed process if it present.
commands to work with debug information
produce very simple debug info without sources
echo 'void foo () {}' | gcc -g -O99 -o - -S -xc - -dA | grep frame_base
dump .debug_info section
readelf --debug-dump=info ./build/trace
objdump --dwarf=info ./build/trace
dump symbol tables of executable
readelf -s ./build/trace
dump file segment headers
readelf -l ./build/trace
dump .eh_frame section
readelf --debug-dump=frames simple
dump list of sections
readelf -S ./build/trace
dump lie section
objdump --dwarf=decodedline
disassemble executable
objdump --d ./build/trace
unwinding-related gcc options
-funwind-tables tells linker to generate .eh_frame section containing CFI. enabled by default if gcc/g++ used for linking -fexceptions Enable exception handling. Generates extra code needed to propagate exceptions. -rdynamic exports the symbols of an executable, allows to print function names in backtrace -fno-omit-frame-pointer instructs the compiler to store the stack frame pointer in a register RBP for x86_64.
Useful links
Assembler tutorials
DWARF links
DWARF 5 Standard (DWARF comittee)
Introduction to the DWARF Debugging Format (DWARF comittee)
Exception handling (DWARF wiki)
Exploring the DWARF debug format information (IBM)
DWARF: function return value types and parameter types (simple tutorial)
Exploiting the Hard-Working DWARF (slides)
Exploiting the Hard-Working DWARF (article)
Local variable location from DWARF info in ARM
Reliable and Fast DWARF-Based Stack Unwinding
Improving debug info for optimized away parameters (GCC summit 2012, GNU extensions)
VARIABLE TRACKING AT ASSIGNMENTS (Redhat, with link to GCC Wiki)
Good itroduction to Debug information
Stack trace and other
Programmatic access to the call stack in C++
Where the top of the stack is on x86
Deep Wizardry: Stack Unwinding (more-less helpful)
Writing a Linux Debugger Part 8: Stack unwinding (other related articles also interesting)
Miscellaneous
Testing pointers for validity (C/C++) (using system calls)