Dose this tool can do parameter slice

[Moriarty002]

If I want to slice only parameter with criterion , like below

static void 
C_bincount(double *x, R_xlen_t n, double *breaks, R_xlen_t nb, int *count,
	   int right, int include_border)
{
...
    for(i = 0 ; i < n ; i++)
	if(R_FINITE(x[i])) { // left in as a precaution
...
	    if(breaks[lo] <= x[i] &&
	       (x[i] < breaks[hi] || (x[i] == breaks[hi] && include_border))) {
		while(hi-lo >= 2) {
		    news = (hi+lo)/2;
		    if(x[i] > breaks[news] || (!right && x[i] == breaks[news]))
			lo = news;
		    else
			hi = news;
		}
...
	    }
	}
}

And I want to only get "breaks,hi,lo......" parameters which relate to variable x
Because the llvm-slicer can get "code" relate to x , I think there may be a way to find only related parameters

[mchalupa]

You should be able to get which parameters are relevant from the dependence graph, so yes, you can use DG to find that out.

[Moriarty002]

Sorry , maybe my question is too obscure .
What I mean is "Is there an 'automatic' way" to do things above.

Find relevant parameters from dependence graph need to read output file and find it out manually .
And , when I try to use llvm-dda-dump , the output file is too large and hard to find relevant , or maybe I miss use?

 llvm-dda-dump --entry C_bincount --forward --dot --pta=fs -c=x test.bc > out.dot

the .bc file is generated from test.c

Because the png is too large to display and github not support svg , I can just put link here .
I don't know why the graph is so large , and how to search relevant parameters from that .

[mchalupa]

By getting the information from the dependence graph I meant to use the API of LLVMDependenceGraph and LLVMNode from C++ (but it would be probably also possible to parse the out.dot). So the answer is: no, there is no automatic way to do that.

or maybe I miss use?

You probably do not want to use llvm-dda-dump, but llvm-dg-dump or llvm-slicer -dump-dg. llvm-dda-dump does not dump the dependence graph, only the results of data dependence analysis (which is not the complete dependence graph).
And I am not sure about the --forward option. This option means that you want to get what is affected by variable x (+it adds also instructions to make the slice executable). From the discussion so far, I thought that you want to get parameters that can affect x (not that are affected by x).

the output file is too large

llvm-dg-dump has the parameter -func that makes it to dump only the given function.

[Moriarty002]

I am sure I want to get the variables affected by x , I wrote a tool using clang-frontend to get the variables from sliced code .
But the sliced code has no headers and I remove the declaration
For example
The original code

# 1 "tmp1.c"
# 1 "<built-in>" 1
# 1 "<built-in>" 3
# 341 "<built-in>" 3
# 1 "<command line>" 1
# 1 "<built-in>" 2
# 1 "tmp1.c" 2

#include <R_ext/Arith.h>
#include <R_ext/Error.h>
#include <R_ext/Print.h>
#include <R_ext/Utils.h>
#include <Rinternals.h>
#include <Rmath.h>
#include <limits.h>
#include <math.h>
#include <stdlib.h>
# 23 "tmp1.c"
#include <string.h>

static void C_bincount(double *x, R_xlen_t n, double *breaks, R_xlen_t nb, int *count, int right, int include_border) {
  R_xlen_t i, lo, hi, nb1 = nb - 1, new;

  memset(count, 0, nb1 * sizeof(int));
  for (i = 0; i < n; i++) {
    lo = 0;
    hi = nb1;
    if (breaks[lo] <= x[i] && (x[i] < breaks[hi] || (x[i] == breaks[hi] && include_border))) {
      while (hi - lo >= 2) {
        new = (hi + lo) / 2;
        if (x[i] > breaks[new] || (!right && x[i] == breaks[new])) {
          lo = new;
        } else {
          hi = new;
        }
      }
      count[lo]++;
    }
  }
}
SEXP C_BinCount(SEXP x, SEXP breaks, SEXP right, SEXP lowest) {
  x = PROTECT(coerceVector(x, REALSXP));
  breaks = PROTECT(coerceVector(breaks, REALSXP));
  R_xlen_t n = XLENGTH(x), nB = XLENGTH(breaks);
  int sr = asLogical(right), sl = asLogical(lowest);
  if (sr == NA_INTEGER) {
    error(("invalid '%s' argument"), "right");
  }
  if (sl == NA_INTEGER) {
    error(("invalid '%s' argument"), "include.lowest");
  }
  SEXP counts = PROTECT(allocVector(INTSXP, nB - 1));
  C_bincount(REAL(x), n, REAL(breaks), nB, INTEGER(counts), sr, sl);
  UNPROTECT(3);
  return counts;
}

The sliced result

static void C_bincount(double *x, R_xlen_t n, double *breaks, R_xlen_t nb, int *count, int right, int include_border) {
  for (i = 0; i < n; i++) {
    lo = 0;
    if (breaks[lo] <= x[i] && (x[i] < breaks[hi] || (x[i] == breaks[hi] && include_border))) {
      while (hi - lo >= 2) {
        new = (hi + lo) / 2;
        if (x[i] > breaks[new] || (!right && x[i] == breaks[new])) {
          lo = new;
        } else {
          hi = new;
        }
      }
      count[lo]++;
    }
  }
}
SEXP C_BinCount(SEXP x, SEXP breaks, SEXP right, SEXP lowest) {
  x = PROTECT(coerceVector(x, REALSXP));
  breaks = PROTECT(coerceVector(breaks, REALSXP));
  R_xlen_t n = XLENGTH(x), nB = XLENGTH(breaks);
  int sr = asLogical(right), sl = asLogical(lowest);
  if (sr == NA_INTEGER) {
    error(("invalid '%s' argument"), "right");
  }
  if (sl == NA_INTEGER) {
    error(("invalid '%s' argument"), "include.lowest");
  }
  C_bincount(REAL(x), n, REAL(breaks), nB, INTEGER(counts), sr, sl);
  UNPROTECT(3);
}

The declaration is missing , is this normal to get the sliced one with no declaration ?
And what if I need both forward and backward slice , what arguments should I use ?

[mchalupa]

And is the declaration present if you skip slicing? That is, just compile the code to LLVM and then (without slicing) use your tool to generate the source code?

[mchalupa]

And what if I need both forward and backward slice , what arguments should I use ?

The forward slice in DG does backward slicing to make the slice executable, is that what you want?

[Moriarty002]

And is the declaration present if you skip slicing? That is, just compile the code to LLVM and then (without slicing) use your tool to generate the source code?

Yes , I use llvm-to-source tmp.bc tmp.c , it still has declaration
but when I use llvm-to-source tmp.sbc tmp.c , it has no declaration

[mchalupa]

Oh, I thought that the output was from your clang-based tool. If the output is from the llvm-to-source, then it is normal that there are no declarations. llvm-to-source does not generate executable code, it is just a debugging tool.