With parallel recompilation enabled, objects made accessible by handles may
have changed between graph construction and graph optimization. Therefore
we must not assume that information on those objects remain the same between
those two phases. To police this, we forbid handle dereferencing during
graph optimization.
Exceptions to this rule are:
- Dereferencing the handle to obtain the raw location of the object. This
is safe since parallel recompilation acquires RelocationLock
- Some places that dereference the handle for a type check. These are checked
to be safe on a case-by-case basis.
R=jkummerow@chromium.org
BUG=
Review URL: https://chromiumcodereview.appspot.com/12049012
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13475 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
HCheckPrototypeMaps currently records the prototype and the holder of the
prototype chain (both ends of the chain) and assumes that the chain elements
and their maps did not change in during the entirety of Crankshaft. The actual
traversal of the prototype chain happens in Lithium at code generation.
With parallel compilation, this assumption is not longer correct.
R=mstarzinger@chromium.org
BUG=
Review URL: https://chromiumcodereview.appspot.com/11864013
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13454 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Previously Crankshaft emitted a generic load for these, now we emit a load of a
named field, guarded by a proto chain check.
LCheckPrototypeMaps now returns the holder, which is for free, because it
already had to check its map as the last step, anyway. This is in sync with what
StubCompiler::CheckPrototype does.
Review URL: https://codereview.chromium.org/11338030
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12847 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
We iteratively remove all dead Hydrogen instruction until we reach a fixed point. We consider an instruction dead if it is unused, has no observable side effects and is deletable. The last part of the condition is currently not very nice: We basically have to whitelist "safe" instructions, because we are missing more detailed dependencies and/or more detailed tracking of side effects.
We disable dead code elimination for now in our test runners, because we have tons of poorly written tests which wouldn't test anymore what they are supposed to test with this phase enabled. To get test coverage for dead code elimination itself, we should enable it on a few build bots. This is not really a perfect state, but the best we can do for now.
This patch includes a few const-correctness fixes, most of them were necessary for this CL.
Review URL: https://codereview.chromium.org/11088027
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12697 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
xmm0 is not saved across runtime call on x64 because MacroAssembler::EnterExitFrameEpilogue preserves only allocatable XMM registers unlike on ia32 where it preserves all registers.
Cleanup handling of shifts: SHR can deoptimize only when its a shift by 0, all other shift never deoptimize.
Fix type inference for i-to-t change instruction. On X64 this ensures that write-barrier is generated correctly.
R=danno@chromium.org
Review URL: https://chromiumcodereview.appspot.com/10868032
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12373 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Safe operations are those that either do not observe unsignedness or have special support for uint32 values:
- all binary bitwise operations: they perform ToInt32 on inputs;
- >> and << shifts: they perform ToInt32 on left hand side and ToUint32 on right hand side;
- >>> shift: it performs ToUint32 on both inputs;
- stores to integer external arrays (not pixel, float or double ones): these stores are "bitwise";
- HChange: special support added for conversions of uint32 values to double and tagged values;
- HSimulate: special support added for deoptimization with uint32 values in registers and stack slots;
- HPhi: phis that have only safe uses and only uint32 operands are uint32 themselves.
BUG=v8:2097
TEST=test/mjsunit/compiler/uint32.js
Review URL: https://chromiumcodereview.appspot.com/10778029
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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
Only handles when x is int32 and y is int32 constant.
BUG=v8:2038
Currently implemented by imul (not fpmul).
x86 and x64 algorithm differs a bit.
x86 implementation is kind of cumbersome, but I couldn't think of better ways.
Review URL: https://chromiumcodereview.appspot.com/10382033
Patch from Zheng Liu <zheng.z.liu@intel.com>.
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11887 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
- Extend HValue interface to allow splitting observed input representation (comming from type feedback) from required input representation (dictated by instruction itself). Currently all instructions except for bitwise binary operations have this representations match. For bitwise binary operations hydrogen builder unconditionaly forces Integer32 representation for those operations that have Double type feedback. Thus causing representation inference to incorrectly count such uses as Integer32 instead of Double. This change also prepares for more fine grained type feedback for inputs of binary operations.
- For phies that are not convertable to Integer32 discard direct and indirect use count of Integer32 type to avoid propagation of these uses to connected phies.
R=jkummerow@chromium.org
BUG=v8:2096
Review URL: https://chromiumcodereview.appspot.com/10540049
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11737 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
tells us that a map can transition to another map when we are generating
code for load operations. This may cause us to deopt if the same routine
is seeing different maps caused by branching in constructors. If so, I
have a different change that is around 100 times more complicated that
lets us generated Crankshaft code for negative lookups.
Review URL: https://chromiumcodereview.appspot.com/10306010
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11524 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
As a special case, for checks on index expressions with the form (expr + constant) if a smaller constant is checked later in the DT also eliminate the check.
Finally, if a larger constant is checked later in the same BB do the more general check (larger constant) earlier instead of the less general one.
This will not cause useless deoptimizations because, since we are in the same BB, all the checks would have been executed anyway.
BUG=
TEST=
Review URL: https://chromiumcodereview.appspot.com/10032029
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11437 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This change allows hydrogen instructions to keep track of instructions
that dominate certain side-effects (GVN flags) in the hydrogen graph. We
use the GVN pass to keep track of side-effects because accurate flags
are already in place.
It also adds a new side-effect (kChangesNewSpacePromotion) indicating
whether an instruction can cause a GC and have objects be promoted to
old-space. An object allocated in new-space is sure to stay on paths not
having said side-effect.
R=erik.corry@gmail.com
TEST=mjsunit/compiler/inline-construct
Review URL: https://chromiumcodereview.appspot.com/10031031
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11270 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
