From ddea208be9e2a8fa281e25ebbc890378dd2aa286 Mon Sep 17 00:00:00 2001 From: Tim Peters Date: Sat, 23 Mar 2002 10:03:50 +0000 Subject: Give Python a debug-mode pymalloc, much as sketched on Python-Dev. When WITH_PYMALLOC is defined, define PYMALLOC_DEBUG to enable the debug allocator. This can be done independent of build type (release or debug). A debug build automatically defines PYMALLOC_DEBUG when pymalloc is enabled. It's a detected error to define PYMALLOC_DEBUG when pymalloc isn't enabled. Two debugging entry points defined only under PYMALLOC_DEBUG: + _PyMalloc_DebugCheckAddress(const void *p) can be used (e.g., from gdb) to sanity-check a memory block obtained from pymalloc. It sprays info to stderr (see next) and dies via Py_FatalError if the block is detectably damaged. + _PyMalloc_DebugDumpAddress(const void *p) can be used to spray info about a debug memory block to stderr. A tiny start at implementing "API family" checks isn't good for anything yet. _PyMalloc_DebugRealloc() has been optimized to do little when the new size is <= old size. However, if the new size is larger, it really can't call the underlying realloc() routine without either violating its contract, or knowing something non-trivial about how the underlying realloc() works. A memcpy is always done in this case. This was a disaster for (and only) one of the std tests: test_bufio creates single text file lines up to a million characters long. On Windows, fileobject.c's get_line() uses the horridly funky getline_via_fgets(), which keeps growing and growing a string object hoping to find a newline. It grew the string object 1000 bytes each time, so for a million-character string it took approximately forever (I gave up after a few minutes). So, also: fileobject.c, getline_via_fgets(): When a single line is outrageously long, grow the string object at a mildly exponential rate, instead of just 1000 bytes at a time. That's enough so that a debug-build test_bufio finishes in about 5 seconds on my Win98SE box. I'm curious to try this on Win2K, because it has very different memory behavior than Win9X, and test_bufio always took a factor of 10 longer to complete on Win2K. It *could* be that the endless reallocs were simply killing it on Win2K even in the release build. --- Include/Python.h | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'Include/Python.h') diff --git a/Include/Python.h b/Include/Python.h index 9724fb7965..d1ffc73c41 100644 --- a/Include/Python.h +++ b/Include/Python.h @@ -61,6 +61,15 @@ #include "pyport.h" +/* Debug-mode build with pymalloc implies PYMALLOC_DEBUG. + * PYMALLOC_DEBUG is in error if pymalloc is not in use. + */ +#if defined(Py_DEBUG) && defined(WITH_PYMALLOC) && !defined(PYMALLOC_DEBUG) +#define PYMALLOC_DEBUG +#endif +#if defined(PYMALLOC_DEBUG) && !defined(WITH_PYMALLOC) +#error "PYMALLOC_DEBUG requires WITH_PYMALLOC" +#endif #include "pymem.h" #include "object.h" -- cgit v1.2.1