[LLVMdev] dynamic data dependence extraction using llvm

Henry Chung zhguanwen at gmail.com
Thu Dec 11 13:08:51 PST 2014

Hi mobi,

Sorry, I am new to clang AST and can not get the point you mentioned. :-(
What I try to do is develop a tool that can analyze data dependence at
runtime. Therefore, I need to analyze trace containing memory accessing
information (eg. arrays within loops). To do that, I first instrument a
recording function to get addresses of load/store instructions. However,
there are 'uninteresting' ld/st instructions, such as load/store
instructions for iteration/index variables, i, j or k. And these
'uninteresting' ld/st instructions will affect my dependence analysis

If clang AST could solve this problem, could you provide more information?


On Thu, Dec 11, 2014 at 2:56 PM, mobi phil <mobi at mobiphil.com> wrote:

> However, as we can see in the llvm-IR, apart from load/store instructions
>> for array accesses we interested, there are lots of load/store instructions
>> for iteration variables, i and j for the above example. And these noise
>> load/store instructions will affect whether we have dependencies across
>> loop iterations (loop-carried dependence) and dependence distance
>> calculation
> without being a guru, also in learning process and having been analyzing a
> similar situation to "hack" some pointer operations, I came to the
> conclusion that the clang AST is the guy. In my case I would have had to
> manipulate the AST, but in your case it seems that you only need to analyse
> the AST.
> And the above statement is made without knowing the content of the work in
> [1]
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