This
section is only relevant for Unix users on platforms supported by
valgrind. Valgrind is an
excellent binary instrumentation platform. Unlike many other
instrumentation platforms, valgrind can deal with code loaded through dlopen().
The callgrind tool can be used to profile foreign code loaded
under SWI-Prolog. Compile the foreign library adding -g
option to gcc or swipl-ld. By setting the environment
variable VALGRIND to yes, SWI-Prolog will not
release loaded shared objects using dlclose(). This trick is
required to get source information on the loaded library. Without,
valgrind claims that the shared object has no debugging information.236Tested
using valgrind version 3.2.3 on x64. Here is the complete
sequence using bash as login shell:
% VALGRIND=yes valgrind --tool=callgrind pl <args>
<prolog interaction>
% kcachegrind callgrind.out.<pid>
Instead
of valgrind, you can use
AddressSanitizer.
Here is a short example for building with asan enabled and then
running the resulting binary. When you exit swipl, a message is
printed and any leaks are printed. During execution, other messages may
be printed out, such as freeing an address twice or using freed or
unallocated memory.
% cd build.sanitize
% cmake -G Ninja -DCMAKE_BUILD_TYPE=Sanitize ..
% ninja
% ASAN_OPTIONS=detect_leaks=1 build.sanitize/src/swipl
<prolog interaction>
% halt
Running LSAN memory leak check (reclaim_memory=1)
No leaks detected
