analyze: search for C/C++ function(s) containing a pattern

[christoffer-nylen]

The user would like to find C/C++ function(s) where a specific pattern is found; for example to study how a variable, literal or code comment is used in a project. This can be helpful when doing code review, traceability analysis, data-flow analysis or control-flow analysis.

Here's a similar stack overflow discussion about this topic.

Example:

A user would like to get a list of the function(s) in foo.c that contains the keyword tmp:

int func1(int x, int y)
{
  return x + y;
}
int func2(int x, int y, int z)
{
  int tmp = x + y;
  tmp *= z;
  return tmp;
}

Suggestions

Approach 1: grep -B

$ grep -nHi -B10 tmp
foo.c-1-int func1(int x, int y)
foo.c-2-{
foo.c-3-  return x + y;
foo.c-4-}
foo.c-5-int func2(int x, int y, int z)
foo.c-6-{
foo.c:7:  int tmp = x + y;
foo.c:8:  tmp *= z;
foo.c:9:  return tmp;

Cons:

• generates much noise
• -B might require large numbers for large functions

Approach 2: git grep -p

$ git grep -nHi -p tmp
foo.c=5=int func2(int x, int y, int z)
foo.c:7:  int tmp = x + y;
foo.c:8:  tmp *= z;
foo.c:9:  return tmp;

Pros:

• Much less noise than grep -B

Cons:

• Also displays the pattern match, which might not always be desirable.

Approach 3: new dextool plugin/feature

Example:

$ dextool analyze -h
-p, --show-function shows the line that contains the function name of a `file:row`

$ grep -nHi -e 'tmp' foo.c | dextool analyze --show-function --from-stdin
foo.c:5: int func2(int x, int y, int z)

$ dextool analyze --show-function foo.c:7
foo.c:1: int func1(int x, int y)

[christoffer-nylen]

(use git grep -p)