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(stabs.info)Builtin Type Descriptors

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Defining Builtin Types Using Builtin Type Descriptors
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   This is the method used by Sun's `acc' for defining builtin types.
These are the type descriptors to define builtin types:

`b SIGNED CHAR-FLAG WIDTH ; OFFSET ; NBITS ;'
     Define an integral type.  SIGNED is `u' for unsigned or `s' for
     signed.  CHAR-FLAG is `c' which indicates this is a character
     type, or is omitted.  I assume this is to distinguish an integral
     type from a character type of the same size, for example it might
     make sense to set it for the C type `wchar_t' so the debugger can
     print such variables differently (Solaris does not do this).  Sun
     sets it on the C types `signed char' and `unsigned char' which
     arguably is wrong.  WIDTH and OFFSET appear to be for small
     objects stored in larger ones, for example a `short' in an `int'
     register.  WIDTH is normally the number of bytes in the type.
     OFFSET seems to always be zero.  NBITS is the number of bits in
     the type.

     Note that type descriptor `b' used for builtin types conflicts with
     its use for Pascal space types (Note: Miscellaneous Types); they
     can be distinguished because the character following the type
     descriptor will be a digit, `(', or `-' for a Pascal space type, or
     `u' or `s' for a builtin type.

`w'
     Documented by AIX to define a wide character type, but their
     compiler actually uses negative type numbers (Note: Negative Type
     Numbers).

`R FP-TYPE ; BYTES ;'
     Define a floating point type.  FP-TYPE has one of the following
     values:

    `1 (NF_SINGLE)'
          IEEE 32-bit (single precision) floating point format.

    `2 (NF_DOUBLE)'
          IEEE 64-bit (double precision) floating point format.

    `3 (NF_COMPLEX)'

    `4 (NF_COMPLEX16)'

    `5 (NF_COMPLEX32)'
          These are for complex numbers.  A comment in the GDB source
          describes them as Fortran `complex', `double complex', and
          `complex*16', respectively, but what does that mean?  (i.e.,
          Single precision?  Double precision?).

    `6 (NF_LDOUBLE)'
          Long double.  This should probably only be used for Sun format
          `long double', and new codes should be used for other floating
          point formats (`NF_DOUBLE' can be used if a `long double' is
          really just an IEEE double, of course).

     BYTES is the number of bytes occupied by the type.  This allows a
     debugger to perform some operations with the type even if it
     doesn't understand FP-TYPE.

`g TYPE-INFORMATION ; NBITS'
     Documented by AIX to define a floating type, but their compiler
     actually uses negative type numbers (Note: Negative Type
     Numbers).

`c TYPE-INFORMATION ; NBITS'
     Documented by AIX to define a complex type, but their compiler
     actually uses negative type numbers (Note: Negative Type
     Numbers).

   The C `void' type is defined as a signed integral type 0 bits long:
     .stabs "void:t19=bs0;0;0",128,0,0,0
   The Solaris compiler seems to omit the trailing semicolon in this
case.  Getting sloppy in this way is not a swift move because if a type
is embedded in a more complex expression it is necessary to be able to
tell where it ends.

   I'm not sure how a boolean type is represented.