Re: Stab type information in string field

[Ian Lance Taylor <ian at airs dot com>]

Ludovic Courtès <ludovic dot courtes at laas dot fr> writes:

> The "stabs" node in the GNU Info tree says that the type-information is
> made of a single number (followed by an "=" sign and so on when defining
> a new type).  For instance, the string field corresponding to a local
> variable declaration like "int x;" is said to look like "x:1" where 1
> corresponds to type "int".
> 
> However, when looking at the stabs of a gcc 2.95.4-compiled excutable
> (with "objdump -G"), it turns out that type information is formatted
> differently.  For instance, the following global variable declaration
> "static int i;" results in the following string field :
> 
>   450    STSYM  0      28     10012304 40870  i:S(0,1)
> 
> Here, the type information is a tuple rather than an integer.  The same
> goes for type definitions (the "t" symbol descriptor) and so on.
> 
> Could someone please explain me how this works?  Did I miss something?

I don't know which version of the document you are reading.  The
current document, available at, e.g.,
    http://sources.redhat.com/gdb/download/onlinedocs/stabs_1.html#SEC1
says this:

    A type-number is often a single number. The GNU and Sun tools
    additionally permit a type-number to be a pair
    (file-number,filetype-number) (the parentheses appear in the
    string, and serve to distinguish the two cases). The file-number
    is 0 for the base source file, 1 for the first included file, 2
    for the next, and so on. The filetype-number is a number starting
    with 1 which is incremented for each new type defined in the
    file. (Separating the file number and the type number permits the
    N_BINCL optimization to succeed more often; see 2.3 Names of
    Include Files).

Ian