Re: [PATCH v4] gdb/manual: Introduce location specs

Pedro Alves
2022-05-27T19:38:17Z

On 2022-05-27 20:34, Eli Zaretskii wrote:
>> Date: Fri, 27 May 2022 20:17:21 +0100
>> Cc: gdb-patches@sourceware.org
>> From: Pedro Alves <pedro@palves.net>
>>
>>>> You start with e.g., just one attribute, like "-function func". This
>>>> makes GDB iterate over all the functions is knows about, finding the
>>>> ones that are called "func". This matches "func(int)", "A::func()",
>>>> "func(long)", etc. GDB collects the PC and source file and line number of
>>>> those functions too along the wa. If you did "break -function func", then
>>>> you end up with a breakpoint with multiple code locations, one
>>>> for each function matched.
>>>>
>>>> Or you start with "a/file.c:100". This makes GDB iterate over all source
>>>> files it knows about, and then for each that has a file name that ends
>>>> with "a/file.c", like e.g., "src/program/a/file.c" and "somelib/a/file.c"
>>>> it searches for line 100, collecting the PC and function name of the
>>>> location. If you did "break a/file.c:100", you end up with a breakpoint with
>>>> multiple locations, one per resolved location. If you did
>>>> "list a/file.c:100", GDB lists the source for around each of the locations.
>>>> Etc.
>>>>
>>>> Or you start with "*0x1000". Conceptually it's the same. GDB finds the code
>>>> locations that match that, resolves that to a location with
>>>> PC/function/source/line, and then the command does what it wants with it.
>>>
>>> Is this supposed to confirm my understanding, or to refute it? I
>>> think it confirms it.
>>
>> I didn't understand what you meant by "attribute can be filled in
>> more than one way", so I explained how it works. If you start with my example
>> for "-function func" example from above, what does "attribute is filled in more
>> than one way" mean in that example?
>
> It means that each of the following attributes of code location can
> have more than one value that satisfies the location spec:
>
> . function prototype
> . possibly file name
> . line number
> . code address

OK.