As yasm has evolved, various minor additions have been made to libyasm to
support the new features. These minor additions have accumulated, and
some contain significant redundancies. In addition, the core focus of
yasm has begun to move away from the front-end commandline program "yasm"
to focusing on libyasm, a collection of reusable routines for use in all
sorts of programs dealing with code at the assembly level, and the modules
that provide specific features for parsing such code.
This libyasm/module update focuses on cleaning up much of the cruft that
has accumulated in libyasm, standardizing function names, eliminating
redundancies, making many of the core objects more reusable for future
extensions, and starting to make libyasm and the modules thread-safe by
eliminating static variables.
Specific changes include:
- Making a symbol table data structure (no longer global). It follows a
factory model for creating symrecs.
- Label symbols now refer only to bytecodes; bytecodes have a pointer to
their containing section.
- Standardizing on *_create() and *_destroy() for allocation/deallocation.
- Adding a standardized callback mechanism for all data structures that
allow associated data. Allowed the removal of objfmt and
dbgfmt-specific data callbacks in their interfaces.
- Unmodularizing linemgr, but allowing multiple linemap instances (linemgr
is now renamed linemap).
- Remove references to lindex; all virtual lines (from linemap) are now
just "line"s.
- Eliminating the bytecode "type" enum, instead adding a standardized
callback mechanism for custom (and standard internal) bytecode types.
This will make it much easier to add new bytecodes, and eliminate the
possibility of type collisions. This also allowed the removal of the
of_data and df_data bytecodes, as objfmts and dbgfmts can now easily
implement their own bytecodes, and the cleanup of arch's bytecode usage.
- Remove the bytecodehead and sectionhead pseudo-containers, instead
making true containers: section now implements all the functions of
bytecodehead, and the new object data structure implements all the
functions of sectionhead.
- Add object data structure: it's a container that contains sections, a
symbol table, and a line mapping for a single object. Every former use
of sectionhead now takes an object.
- Make arch interface and all standard architectures thread-safe:
yasm_arch_module is the module interface; it contains a create()
function that returns a yasm_arch * to store local yasm_arch data; all
yasm_arch_module functions take the yasm_arch *.
- Make nasm parser thread-safe.
To be done in phase 2: making other module interfaces thread-safe. Note
that while the module interface may be thread-safe, not all modules may be
written in such a fashion (hopefully all the "standard" ones will be, but
this is yet to be determined).
svn path=/trunk/yasm/; revision=1058
Peter Johnson