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(stabs.info)Stabs Format

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Overview of Stab Format
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   There are three overall formats for stab assembler directives,
differentiated by the first word of the stab.  The name of the directive
describes which combination of four possible data fields follows.  It is
either `.stabs' (string), `.stabn' (number), or `.stabd' (dot).  IBM's
XCOFF assembler uses `.stabx' (and some other directives such as
`.file' and `.bi') instead of `.stabs', `.stabn' or `.stabd'.

   The overall format of each class of stab is:

     .stabs "STRING",TYPE,OTHER,DESC,VALUE
     .stabn TYPE,OTHER,DESC,VALUE
     .stabd TYPE,OTHER,DESC
     .stabx "STRING",VALUE,TYPE,SDB-TYPE

   For `.stabn' and `.stabd', there is no STRING (the `n_strx' field is
zero; see Note: Symbol Tables).  For `.stabd', the VALUE field is
implicit and has the value of the current file location.  For `.stabx',
the SDB-TYPE field is unused for stabs and can always be set to zero.
The OTHER field is almost always unused and can be set to zero.

   The number in the TYPE field gives some basic information about
which type of stab this is (or whether it _is_ a stab, as opposed to an
ordinary symbol).  Each valid type number defines a different stab
type; further, the stab type defines the exact interpretation of, and
possible values for, any remaining STRING, DESC, or VALUE fields
present in the stab.  Note: Stab Types, for a list in numeric order
of the valid TYPE field values for stab directives.