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Wed Jan 25 16:39:18 2006 Tim Janik <timj@imendio.com> * glib/gslice.c: honour g_mem_gc_friendly settings when freeing slices, make sure g_mem_gc_friendly is properly initialized. * gmem.[hc]: ensure g_mem_gc_friendly is initialized from G_DEBUG upon the first allocation. applied some branching optimizations. * docs/macros.txt: reflected --enable-gc-friendly change and described ENABLE_GC_FRIENDLY_DEFAULT as well as G_DEBUG=gc-friendly. * configure.in: changed --enable-gc-friendly=yes to define ENABLE_GC_FRIENDLY_DEFAULT. * glib/garray.c: changed ENABLE_GC_FRIENDLY macro #ifdef-s to if (G_UNLIKELY (g_mem_gc_friendly)). * glib/gtree.c: * glib/ghash.c: removed ENABLE_GC_FRIENDLY code which is now taken care of by g_slice_free1(). * tests/slice-test.c: fixed leaks, reported by Kjartan Maraas.
82 lines
3.5 KiB
Plaintext
82 lines
3.5 KiB
Plaintext
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GLib's configure options and corresponding macros
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=================================================
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--enable-debug=no
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-DG_DISABLE_ASSERT -DG_DISABLE_CHECKS
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--enable-debug=minimum [default for stable branches]
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none
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--enable-debug=yes [default for development branches]
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-DG_ENABLE_DEBUG -g
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--enable-gc-friendly=yes
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#define ENABLE_GC_FRIENDLY_DEFAULT 1
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--disable-mem-pools=yes
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#define DISABLE_MEM_POOLS 1
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Besides these, there are some local feature specific options, but my main
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focus here is to concentrate on macros that affect overall GLib behaviour
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and/or third party code.
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Notes on GLib's internal and global macros
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==========================================
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ENABLE_GC_FRIENDLY_DEFAULT
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Newly allocated memory that isn't directly initialized, as well
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as memory being freed should be reset to 0. The point here is to
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allow memory checkers and similar programs that use bohem GC alike
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algorithms to produce more accurate results.
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This can also be accomplished by setting the environment variable
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G_DEBUG=gc-friendly.
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DISABLE_MEM_POOLS
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Many small chunks of memory are often allocated via collective pools
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in GLib and are cached after release to speed up reallocations.
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For sparse memory systems this behaviour is often inferior, so
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memory pools can be disabled to avoid excessive caching and force
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atomic maintenance of chunks through the g_malloc/g_free.
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Code currently affected by this macro:
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- GList, GSList, GNode allocations
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- GMemChunks become basically non-effective
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- GSignal disables all caching (potentially very slow)
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- GType doesn't honour the GTypeInfo n_preallocs field anymore
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- the GBSearchArray flag G_BSEARCH_ALIGN_POWER2 becomes non-functional
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G_DISABLE_ASSERT
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The g_assert() and g_assert_not_reached() become non-functional
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with this define. The motivation is to speed up end-user apps by
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avoiding expensive checks.
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This macro can affect third-party code. --enable-debug=no will only
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disable the assertion macros for GLib itself, but third-party code
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that passes -DG_DISABLE_ASSERT to the compiler upon its own build
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will end up with the non-functional variants after including glib.h
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as well.
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NOTE: Code inside the assertion macros should not have side effects
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that affect the operation of the program.
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G_DISABLE_CHECKS
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This macro is similar to G_DISABLE_ASSERT, it affects third-party
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code as mentioned above and the NOTE about G_DISABLE_ASSERT applies
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too. The macros that become non-functional here are
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g_return_if_fail(), g_return_val_if_fail(), g_return_if_reached() and
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g_return_val_if_reached().
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Additionally the glib_mem_profiler_table and g_mem_profile() from
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gmem.h become non-functional if this macro is supplied.
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This macro also switches off certain checks in the GSignal code.
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G_ENABLE_DEBUG
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Quite a bit of additional debugging code is compiled into GLib for this
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macro, and since it is a globally visible define, third-party code may
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be affected by it similar to G_DISABLE_ASSERT.
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The additional code executed/compiled for this macro currently involve:
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- extra validity checks for GDate
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- memory profiling traps in gmem.c (consult debugging.txt for details)
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- BREAKPOINT abortion for fatal log levels in gmessage.c instead of
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plain abort() to allow debuggers trapping and overriding them
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- added verbosity of gscanner.c to catch deprecated code paths
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- added verbosity of gutils.c to catch deprecated code paths
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- object ref/unref traps (consult debugging.txt) and object bookkeeping
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in gobject.c
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- extra validity checks in gsignal.c
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2000/12/28 Tim Janik
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