When code objects in the heap for FUNCTIONs and OPTIMIZED_FUNCTIONs are marked by the GC, their prologue is patched with a call to a stub that removes the patch. This allows the collector to quickly identify code objects that haven't been executed since the last full collection (they are the ones that sill contain the patch). The functionality is currently disabled, but can be activated by specifying the "--age-code".
R=mstarzinger@chromium.org
Review URL: https://codereview.chromium.org/10837037
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12898 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This enables code flushing even with incremental marking enabled and
fully shares the function link field in JSFunctions between candidates
for code flushing and the optimized functions list. If a candidate for
code flushing gets optimized, it will be evicted from the candidates
list.
R=ulan@chromium.org
BUG=v8:1609
Review URL: https://codereview.chromium.org/11140025
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12796 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This is another preparation for incremental code flushing. Instead of
linking candidates using the code entry field, we use the next pointer
that is also used to link optimized functions together. Since we only
support flushing of unoptimized code, this field can be shared.
R=ulan@chromium.org
BUG=v8:1609
Review URL: https://codereview.chromium.org/11141023
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12734 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Now a map points to a transition array which contains the descriptor array. The descriptor array is now immutable. The next step is to share the descriptor array with all back-pointed maps as long as there is a single line of extension. Maps that require a descriptor array but don't need transitions will still need a pseudo-empty transition array to contain the descriptor array.
Review URL: https://chromiumcodereview.appspot.com/10816005
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12298 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
In this design maps contain descriptor arrays, which in turn can contain transition arrays. If transitions are needed when no descriptor array is present, a descriptor array without real descriptors is inserted just so it can point at the transition array.
The transition array does not contain details about the field it transitions to. In order to weed out transitions to FIELDs from CONSTANT_FUNCTION (what used to be MAP_TRANSITION vs CONSTANT_TRANSITION), the transition needs to be followed and the details need to be looked up in the target map. CALLBACKS transitions are still easy to recognize since the transition targets are stored as an AccessorPair containing the maps, rather than the maps directly.
Currently AccessorPairs containing a transition and an accessor are shared between the descriptor array and the transition array. This simplifies lookup since we only have to look in one of both arrays. This will change in subsequent revisions, when descriptor arrays will become shared between multiple maps, since transitions cannot be shared.
Review URL: https://chromiumcodereview.appspot.com/10697015
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11994 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This makes back pointers in the map transition tree explicit by having
accurate back pointers throughout the lifetime of maps instead of
establishing and destroying back pointers before and after each marking
phase. This is a prerequisite for being able to clear map transitions
during incremental marking.
R=vegorov@chromium.org
BUG=v8:1465
Review URL: https://chromiumcodereview.appspot.com/10381053
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11528 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This simple refactoring makes it very clear that clearing non-live transitions
actually consists of 2 quite separate things. Things would even be nicer if the
prototype transitions were represented by a separate data structure instead of
reusing FixedArray in an interesting way once again.
As an additional bonus, this CL makes it possible to read each of the methods in
question on a 30" screen without scrolling!
Review URL: https://chromiumcodereview.appspot.com/9169045
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10501 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This refactoring (almost) gets rid of the requirement to get the target
object address for an object pointer embedded in code objects. This is
not possible on MIPS as pointers are encoded using two instructions. All
usages of RelocInfo::target_object_address() are (almost) obsoleted by
this change. The serializer still uses it, so MIPS will not yet work
with snapshots turned on.
R=danno@chromium.org,vegorov@chromium.org
Review URL: http://codereview.chromium.org/8245007
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@9597 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
All slots that were recorded on these objects during incremental marking should be ignored as they are no longer valid.
To filter such invalidated slots out during slots buffers iteration we set all markbits under the invalidated code object to 1 after the code space was swept and before slots buffers are processed.
R=erik.corry@gmail.com
BUG=v8:1713
TEST=test/mjsunit/regress/regress-1713.js
Review URL: http://codereview.chromium.org/7983045
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@9402 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
The "live bytes" count is *really* a "marked black" count - i.e., the count of bytes *known* to be live.
Fix aggravating bug on X64 where assembler code used a value that was off
by a factor of 2^31.
Ensure that sweeping clears live-bytes. Added other missing increments.
Added print statements to trace live-byte modifications, under a flag.
Still a few cases of undercounting left.
(New issue to merge from GC branch to bleeding_edge)
Review URL: http://codereview.chromium.org/7970009
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@9338 ce2b1a6d-e550-0410-aec6-3dcde31c8c00