similar to: [LLVMdev] Tracing Value Dependency Chains

It would be great help if someone can point me to similar code in Analysis or Transform, i.e. tracing value dependencies chains. Thanks, Manish On Wed, Aug 3, 2011 at 10:47 AM, Manish Gupta <manishg at cs.ucsd.edu> wrote: > Hello All, > > What would be the best way to trace Value Dependency Chains in LLVM. Can I > use some API to perform this? > > The use-def chain

On 8/4/11 1:53 PM, Manish Gupta wrote: > It would be great help if someone can point me to similar code in > Analysis or Transform, i.e. tracing value dependencies chains. If I understand correctly, given an instruction I, you want to find its operands o1 through oN, and then find the instructions (or LLVM values) that generate the values o1 through oN, and then find the instructions

Hey John, Yes this is what I am looking for. I wrote a code as I described in my first mail and I am getting desired result except when the chain encounters load instruction (you have also mentioned the that u skip loads). I think the recursive trace back for a Value V depending on Operands (o1,...oN) should terminate at the nearest definition of the oN (i.e. it is not an instruction but a LLVM

On 8/4/11 2:45 PM, Manish Gupta wrote: > Hey John, > > Yes this is what I am looking for. I wrote a code as I described in my > first mail and I am getting desired result except when the chain > encounters load instruction (you have also mentioned the that u skip > loads). Okay. Just out of curiosity, is your static slice local (stopping at function arguments) or

Hi, I need to find out all the places where the value of a variable is being used. For this I have to implement reaching definitions(def-use chains). When I searched for its implementation I found Iterating over def-use & use-def chains <http://llvm.org/docs/ProgrammersManual.html#iterate_chains>. will this work for finding the places where a variable is reaching? I tried to use

Hi Duncan Sands, I frankly don't know what a variable gets converted to (SSA register or memory chunk). What I meant is, for example I1: int i, j=10; I2: scanf("%d", &j); I3: i = j + 1; Here I want to know whether the value of j in I1 reaches I3 or not. Best Regards, Srikanth Vaindam you didn't define what you mean by a variable. LLVM has virtual registers which are

What member function to use if I wish to operate on results of an instruction. eg. Instruction %1 = getelementptr inbounds [10 x i32]* %a, i32 0, i32 %0 I->getOperand will give me the operands. How should I get hold of %1? Thanks, Manish -------------- next part -------------- An HTML attachment was scrubbed... URL:

Thanks Everyone for the info. I am planning to work with DSA on llvm-2.9. Hope it is working as John mentioned. Manish On Tue, Sep 20, 2011 at 7:06 AM, John Criswell <criswell at illinois.edu>wrote: > On 9/19/11 9:12 PM, Manish Gupta wrote: > > Dear All, > > I am curious to know the reason for removal of andersen pointer analysis. > Is it because of some issues? We

The README at the location shared by John says "DSA is undergoing significant changes and may not be entirely stable or correct. See lib/DSA/README" So, I was wondering from where should one pick the code. Although I will start my analysis and see how results turn out to be. But any comments on this line will be helpful. Thanks Manish On Tue, Sep 20, 2011 at 5:13 PM, Manish Gupta

On 5/3/11 4:08 PM, tarun agrawal wrote: > HI > > I know it is a very simple question not worth asking here but I am > really struggling pls help me out.. This is a question worth asking; it's just that not everyone can answer all the time. :) If all you want to do is to follow the SSA def-use chain within a single function, then this is very easy. All you have to do is use

Thanks for your response! But I want to determine wheter the specific variable's value has been changed between two usages of variable, and wheter the parameter's value is changed in a function. Like the reaching definition analysis, and ud chains. 2012/8/9 ��f�� (Wei-Ren Chen) <chenwj at iis.sinica.edu.tw>: > On Thu, Aug 09, 2012 at 11:16:15AM +0800, Jianfei Hu wrote: >>

On Thu, Aug 09, 2012 at 11:16:15AM +0800, Jianfei Hu wrote: > Hello All, > > Is the use-define chain related API avaliable in LLVM? I want > to get the information > about the variables' value changes at different points in the program. Is this [1] fit your need? HTH, chenwj [1] http://llvm.org/docs/ProgrammersManual.html#iterate_chains -- Wei-Ren Chen (陳韋任)

Dear Tarun, It just occurred to me that this may or may not be what you are asking about. This only finds basic blocks along the def-use chain of an instruction; it does not find all basic blocks along all paths between two instructions. I don't know of an algorithm off-hand for the latter, but if you understand how to iterate over def-use chains and the control-flow graph, then

Thanks John, I know how to iterate through def-use chains and I also have realized the need for an algorithm to do the work. But the algorithm I am able to figure out is not linear in time. It wold be a great help if someone suggest me a way to get all basic-block along all path between two instruction. On Wed, May 4, 2011 at 7:00 AM, John Criswell <criswell at illinois.edu> wrote: >

Thanks Michael. I wish to get Type of %1 i.e. result of instruction. Let me try out your suggestion. But It is still not clear to me how will dyn_cast will help here. I already have pointer to this particular instruction. On Mon, Aug 1, 2011 at 5:34 PM, Michael Ilseman <michael at lunarg.com> wrote: > In LLVM, %1 is the instruction itself. This is because LLVM IR is in > SSA, so the

On Thu, Aug 9, 2012 at 6:57 AM, Jianfei Hu <hujianfei258 at gmail.com> wrote: > Thanks for your response! > > But I want to determine wheter the specific variable's value has been > changed between > two usages of variable, and wheter the parameter's value is changed in > a function. Like the > reaching definition analysis, and ud chains. > > > 2012/8/9

In LLVM, %1 is the instruction itself. This is because LLVM IR is in SSA, so the "=" really means equality. If you look at a use of %1, e.g. as an operand to another instruction, you'll see that it's the instruction itself that is there (i.e. you can dyn_cast<Instruction> it). On Mon, Aug 1, 2011 at 5:27 PM, Manish Gupta <manishg at cs.ucsd.edu> wrote: > What

Maybe My statement is not clear. Take an example: main.c: int global; void fun(int array[], int i){ array[i] = i + 1; global = i; } int main(){ int arr[40], i = 0; fun(arr, 10); return 0; } Can I determine whether the value of arr array and global variable have changed after the function call, fun(arr, 10), by LLVM API? It could be more complicated considerring the nested function

On 8/9/12 12:40 AM, Jianfei Hu wrote: > Maybe My statement is not clear. Take an example: > main.c: > int global; > void fun(int array[], int i){ > array[i] = i + 1; > global = i; > } > > int main(){ > int arr[40], i = 0; > fun(arr, 10); > return 0; > } > Can I determine whether the value of arr array and global variable > have changed

Hello All, Is the use-define chain related API avaliable in LLVM? I want to get the information about the variables' value changes at different points in the program. Best wishes.