Help with flags for static analysis

Help with flags for static analysis

[Abigail Matthews]

Hello,

I am a PhD student in Computer Science at UW Wisconsin Madison. I have been
using gcc with the -fdump-rtl-expand-lineno and
-fdump-tree-cfg-lineno flags for my research doing some static analysis of
the linux kernel. I am in particular trying to parse inside line number
pairs for loops and function calls/pointers. For loops I want to find the
loop length/number of iterations or what the loop is dependent on. For
function calls and pointers I want to follow the function calls
recursively and repeat some of my static analysis along the full call
stack.

I am trying to find some flags that can give me more information than I
have coming from the current flags (or maybe differently formatted info),
but I am struggling to understand the flag options and dump formats. Even
with the flags I am already using to some success I find myself
struggling to understand the information already there, even with the
existing documentation. Is there anyone who knows more about these flags
and may be able to hear a bit more the info I am looking for and help point
me in the right direction? Any pointers or suggestions would be really
helpful.

Thank you,
Abby

Re: Help with flags for static analysis

[Jonathan Wakely]

On Tue, 20 Jul 2021 at 17:37, Abigail Matthews wrote:
>
> Hello,
>
> I am a PhD student in Computer Science at UW Wisconsin Madison. I have been
> using gcc with the -fdump-rtl-expand-lineno and
> -fdump-tree-cfg-lineno flags for my research doing some static analysis of
> the linux kernel. I am in particular trying to parse inside line number
> pairs for loops and function calls/pointers. For loops I want to find the
> loop length/number of iterations or what the loop is dependent on. For
> function calls and pointers I want to follow the function calls
> recursively and repeat some of my static analysis along the full call
> stack.
>
> I am trying to find some flags that can give me more information than I
> have coming from the current flags (or maybe differently formatted info),
> but I am struggling to understand the flag options and dump formats. Even
> with the flags I am already using to some success I find myself
> struggling to understand the information already there, even with the
> existing documentation. Is there anyone who knows more about these flags
> and may be able to hear a bit more the info I am looking for and help point
> me in the right direction? Any pointers or suggestions would be really
> helpful.

Those options are meant to help GCC developers debug GCC itself, not
to expose the information for other uses. As a result, I'm not
surprised you're finding the output to be unhelpful for your purposes.

Maybe Dave Malcolm (CC'd) can offer a better suggestion, as he's been
working on the -fanalyzer feature.