Approaching DWARF
When introducing the Go standard library debug/dwarf earlier, we demonstrated several examples of reading source files, function names, and function parameter information from DWARF. However, we didn't discuss:
How exactly is this DWARF debug information generated? We know it's generated by the compiler and linker, but what is the specific generation process? What roles do the compiler and linker each play in this process?
Which DWARF descriptive capabilities are utilized when generating DWARF debug information? How does the Go toolchain use DWARF to describe different types, variables, constants, functions (including parameters, return values and local variables), call stacks, and line number tables? Understanding this is essential before we can implement correct reading of this information. This includes when implementing debuggers later - we may need to frequently write small test program snippets to examine the DWARF debug information generated by the Go compiler toolchain, understand it, and then attempt to read it and correlate it with source code.
Is the Go standard library's DWARF data reading and writing capability complete enough? When preparing examples of DWARF data reading earlier, we found that not all key descriptive information (.debug_ sections) in DWARF v4 is being read, such as call stack information in .debug_frame.
Besides the Go standard library, are there other better maintained Go DWARF open source libraries? For example, the go-delve/delve debugger has evolved almost in parallel with Go language development. During this time, the Go team's DWARF support was limited, so the Delve developers had to solve DWARF data reading and writing problems.
What libraries are available to help us handle DWARF data reading and writing when implementing a DWARF-based symbolic debugger? Different language constructs in different programming languages have different DWARF descriptions. Implementing DWARF data reading and writing logic from scratch would be a massive undertaking. We need to compare implementations in the Go standard library, Delve and other projects to choose suitable libraries.
These are questions we must consider when moving towards engineering implementation after understanding debugging principles. Let's continue to explore these topics in this section.