adding debug variants?
vincent-opdarw at vinc17.org
Sun Mar 11 13:41:16 PDT 2007
On 2007-03-11 10:14:39 -0700, Paul Beard wrote:
> All I had to do was add "-O0 -Wall -g" to the CFLAGS but for many users that
> might not be something they're comfortable with. Add to that the additional
> complication of the instructions reading "-O0 -g- Wall" (the difference a
> space can make) and the resulting failures and it might prove frustrating.
IMHO, instead of a variant, MacPorts should allow users to specify
default compiler options (e.g., CFLAGS) since there are too many
possibilities. For instance, though -O0 is better for real debugging
purpose, it degrades performance, and in general, -O1 is fine for
normal use and still allows a significant core dump in case of crash.
Indeed the gcc man page says about the -g option:
GCC allows you to use -g with -O. The shortcuts taken by optimized
code may occasionally produce surprising results: some variables
you declared may not exist at all; flow of control may briefly move
where you did not expect it; some statements may not be executed
because they compute constant results or their values were already
at hand; some statements may execute in different places because
they were moved out of loops.
Nevertheless it proves possible to debug optimized output. This
makes it reasonable to use the optimizer for programs that might
Vincent Lefèvre <vincent at vinc17.org> - Web: <http://www.vinc17.org/>
100% accessible validated (X)HTML - Blog: <http://www.vinc17.org/blog/>
Work: CR INRIA - computer arithmetic / Arenaire project (LIP, ENS-Lyon)
More information about the macports-users