We currently bundle a version of elfutils with patches to export
additional stack tracing functionality. This has a few drawbacks:
- Most of drgn's build time is actually building elfutils.
- Distributions don't like packages that bundle verions of other
packages.
- elfutils, and thus drgn, can't be built with clang.
Now that we've replaced the elfutils DWARF unwinder with our own, we
don't need the patches, so we can drop the bundled elfutils and fix
these issues.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
The Doxygen documentation for libdrgn has bit-rotted over time. Bring
back the Internal module, clean up a few renamed members and parameters,
and fix broken parsing caused by the generic definition macros.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
The current mixed Python/C implementation works well, but it has a
couple of important limitations:
- It's too slow for some common use cases, like iterating over large
data structures.
- It can't be reused in utilities written in other languages.
This replaces the internals with a new library written in C, libdrgn. It
includes Python bindings with mostly the same public interface as
before, with some important improvements:
- Types are now represented by a single Type class rather than the messy
polymorphism in the Python implementation.
- Qualifiers are a bitmask instead of a set of strings.
- Bit fields are not considered a separate type.
- The lvalue/rvalue terminology is replaced with reference/value.
- Structure, union, and array values are better supported.
- Function objects are supported.
- Program distinguishes between lookups of variables, constants, and
functions.
The C rewrite is about 6x as fast as the original Python when using the
Python bindings, and about 8x when using the C API directly.
Currently, the exposed API in C is fairly conservative. In the future,
the memory reader, type index, and object index APIs will probably be
exposed for more flexibility.
