NEVILLE%umass-cs.csnet@csnet-relay.arpa (07/12/85)
i am in the (very) early stages of some modifications to the portable
("machine-independent part") of the Unix C compiler. Actually, for reasons
already hashed out locally, the changes will be implemented as a filter
inserted between the pre-processor and the compiler. This filter must
recognize a number of new storage classes, scoping of variables, etc., and
thus must be in effect a compiler-sans-code-generator.
i have been digging around in the compiler source to try to understand
the data structures used, symbol table access, and all that rot but
reading lex/yacc generated code with such a proliferation of global
variables is difficult at best.
If anyone who is familiar with the compiler source could help on this,
it would be sure to save a great deal of time and coffee. What i need to
do isn't that complicated :
Having built in a new storage class (say, CLASS_3),
1. Parse the program, noting when a variable of class CLASS_3
is referenced (for either read OR write)
2. Replace the variable reference with a pre-defined macro expansion
3. Copy all other text onto the output stream
Of course, there will be a little footwork required to generate/copy text
while working at both the character and token levels, but that's not all
that difficult.
As i doubt that the rest of the folks on the net would be interested in
replies to this posting, you can respond directly to me.
ThanX,
Neville D. Newman
newman@umass-cs (CSnet)