SecuritySNACCRuntime/doc/modifying.tex

   1 % file: .../doc/modifying.tex
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   3 % $Header: /cvs/Darwin/Security/SecuritySNACCRuntime/doc/modifying.tex,v 1.1.1.1 2001/05/18 23:14:10 mb Exp $
   4 % $Log: modifying.tex,v $
   5 % Revision 1.1.1.1  2001/05/18 23:14:10  mb
   6 % Move from private repository to open source repository
   7 %
   8 % Revision 1.1.1.1  1999/03/16 18:05:54  aram
   9 % Originals from SMIME Free Library.
  10 %
  11 % Revision 1.1  1997/01/01 22:47:44  rj
  12 % first check-in
  13 %
  14
  15 \chapter{\label{modifying-chapter}Modifying the Compiler}
  16
  17 The compiler consists of about 30,000 lines of yacc, lex and C code
  18 (another 7,000+ for the runtime library routines).  The best way to
  19 understand the compiler internals is to understand the module data
  20 structure ({\ufn \dots/compiler/core/asn1module.h}) and to read the compiler
  21 chapter in this document to gain a conceptual understanding of each
  22 pass of the compiler.
  23
  24 The most common form of modification will likely be for macro
  25 handling.  To understand this, look at the way the OBJECT-TYPE macro is
  26 treated in:
  27 \begin{description}
  28 \item[lex-asn1.l] {add any new keywords}
  29 \item[parse-asn1.y] { parse the macro into the desired data structure.
  30 Use the existing productions as much as possible.}
  31 \item[link-type.c] { link any type defined or referenced in the
  32 macro}
  33 \item[link-values.c] { link any value defined or referenced in the
  34 macro}
  35 \item[do-macros.c] { perform any semantic action for the macro }
  36
  37 \item[normalize.c] { move any type and value definitions in the macro
  38 to the top level so the code generator can generate code for them
  39 (without looking in the macro).}
  40
  41 \item[code generators] { to convert any special semantics into useful
  42 C or C++.  This phase is likely to be dependent on the generated
  43 code's target environment.}
  44 \end{description}
  45
  46 In general I have tried to put comments where funky things happen and
  47 to use function and variable names that are meaningful.  However,
  48 things may get ugly in certain places.  Thesis writing is harmful to
  49 your coding style!