LCA: Static analysis with GCC plugins

Posted Jan 25, 2010 14:38 UTC (Mon) by jwakely (subscriber, #60262)
In reply to: LCA: Static analysis with GCC plugins by clugstj
Parent article: LCA: Static analysis with GCC plugins

Oops, my mistake. I misread it as saying flow.js was used for checking that idiom in Mozilla code, and could also be used for other code such as the kernel. The idiom makes perfect sense in C.

LCA: Static analysis with GCC plugins

Posted Jan 25, 2010 14:45 UTC (Mon) by jwakely (subscriber, #60262) [Link] (1 responses)

Actually it looks like I was right:
https://bugzilla.mozilla.org/show_bug.cgi?id=441362
https://bugzilla.mozilla.org/show_bug.cgi?id=443286
https://bugzilla.mozilla.org/show_bug.cgi?id=442358

LCA: Static analysis with GCC plugins

Posted Feb 10, 2010 3:44 UTC (Wed) by bzbarsky (guest, #63464) [Link]

Yeah, those are all code that used to be C code, then was converted to compiling as C++ with minimal changes made in the process. Now it's starting to use C++ idioms as needed to make the code more understandable, etc.

multiple returns in C

Posted Jan 28, 2010 3:46 UTC (Thu) by thedevil (guest, #32913) [Link] (1 responses)

Actually there's a better way to do this even in C:

static int foobar_return_handler(void* some_pointer, int destruct, int result)
{
  if (some_pointer)
    free(some_pointer);
  if (destruct)
    do_destruct();
  return result;
}

int foobar()
{
  void* some_pointer = malloc(sizeof(some_type));
  if (!some_pointer)
    return foobar_return_handler(0, 1, -1);
  int foo_result = foo(some_pointer);
  if (foo_result < 0)
    return foobar_return_handler(some_pointer, 1, foo_result);
  int bar_result = bar(some_pointer, foo_result);
  if (bar_result < 0)
    return foobar_return_handler(some_pointer, 1, bar_result);
  return foobar_return_handler(some_pointer, 0, bar_result);
}

multiple returns in C

Posted Jan 28, 2010 10:04 UTC (Thu) by dgm (subscriber, #49227) [Link]

Another idiom I often use is separating resource allocation from actual computation:

int foobar1 (some_type * some_pointer)
{
  int result = foo (some_pointer);
  if (result < 0)
    result = bar (some_pointer, result);
  return result;
}

int foobar()
{
  int result = -1;
  void * some_pointer = malloc (sizeof (some_type));
  if (some_pointer) {
    result = foobar1 (some_pointer);
    free (some_pointer);
  }
  return result;
}