CODEWITHSUNDEEP
gdbgdb-python
Dov Grobgeld
Dov Grobgeld

Reputation: 4983

How to return a gdb.Value() from a string?

Consider the following gdb commands that output the same text string.

(gdb) print foo
(gdb) python print(gdb.lookup_symbol('foo'))

In this case gdb.lookup_symbol() returns a gdb.Value() instance as expected, and the stringification of it is equivalent to the default gdb stringification.

But now consider the following equivalent case:

(gdb) print *&foo

The *& is a noop, but trying to use gdb.lookup_symbol('*&foo') does not work. So my question is whether it is possible to make use of gdb's command line dereferencing parser from python, and then get a gdb.Value in return?

Upvotes: 0

Views: 1246

Answers (1)

Employed Russian
Employed Russian

Reputation: 213754

trying to use gdb.lookup_symbol('*&foo') does not work.

That's because there is no symbol named *&foo in the binary.

whether it is possible to make use of gdb's command line dereferencing parser from python, and then get a gdb.Value in return?

Your question is not very clear, but I think you are asking for parse_and_eval:

Function: gdb.parse_and_eval (expression)
Parse expression, which must be a string, as an expression in the current language,
evaluate it, and return the result as a gdb.Value.

This function can be useful when implementing a new command (see Commands In Python),
as it provides a way to parse the command’s argument as an expression.
It is also useful simply to compute values, for example, it is the only way to get
the value of a convenience variable (see Convenience Vars) as a gdb.Value.

Upvotes: 2

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