view contrib/fuzz/pyutil.cc @ 50942:75d3306fbc9a stable

tags: avoid expensive access to repo.changelog in a loop

repo.changelog needs some cache invalidation when run on filtered repository.
Accessing it in that loop can be expensive when there is many heads (e.g.
mozilla try and it 25 000 heads).

Note that the loop itself seems useless, but after this patch it no longer take
about ⅛  of the time we spend computing cache for mozilla try.

before :
! wall 0.350994 comb 0.350000 user 0.330000 sys 0.020000 (median of 28)

after :
! wall 0.319520 comb 0.310000 user 0.290000 sys 0.020000 (median of 30)

#include "pyutil.h"

#include <iostream>
#include <string>

namespace contrib
{

#if PY_MAJOR_VERSION >= 3
#define HG_FUZZER_PY3 1
PyMODINIT_FUNC PyInit_parsers(void);
#else
PyMODINIT_FUNC initparsers(void);
#endif

static char cpypath[8192] = "\0";

static PyObject *mainmod;
static PyObject *globals;

void initpy(const char *cselfpath)
{
#ifdef HG_FUZZER_PY3
	const std::string subdir = "/sanpy/lib/python3.8";
#else
	const std::string subdir = "/sanpy/lib/python2.7";
#endif

	/* HACK ALERT: we need a full Python installation built without
	   pymalloc and with ASAN, so we dump one in
	   $OUT/sanpy/lib/python2.7. This helps us wire that up. */
	std::string selfpath(cselfpath);
	std::string pypath;
	auto pos = selfpath.rfind("/");
	if (pos == std::string::npos) {
		char wd[8192];
		if (!getcwd(wd, 8192)) {
			std::cerr << "Failed to call getcwd: errno " << errno
			          << std::endl;
			exit(1);
		}
		pypath = std::string(wd) + subdir;
	} else {
		pypath = selfpath.substr(0, pos) + subdir;
	}
	strncpy(cpypath, pypath.c_str(), pypath.size());
	setenv("PYTHONPATH", cpypath, 1);
	setenv("PYTHONNOUSERSITE", "1", 1);
	/* prevent Python from looking up users in the fuzz environment */
	setenv("PYTHONUSERBASE", cpypath, 1);
#ifdef HG_FUZZER_PY3
	std::wstring wcpypath(pypath.begin(), pypath.end());
	Py_SetPythonHome(wcpypath.c_str());
#else
	Py_SetPythonHome(cpypath);
#endif
	Py_InitializeEx(0);
	mainmod = PyImport_AddModule("__main__");
	globals = PyModule_GetDict(mainmod);

#ifdef HG_FUZZER_PY3
	PyObject *mod = PyInit_parsers();
#else
	initparsers();
	PyObject *mod = PyImport_ImportModule("parsers");
#endif

	PyDict_SetItemString(globals, "parsers", mod);
}

PyObject *pyglobals()
{
	return globals;
}

} // namespace contrib