Port r19715 (0d6d244)
Original commit message:
Lithium currently supports 3 division-like operations on integral
operands: "Normal" division (rounding towards zero), flooring division
(rounding towards -Infinity) and modulus calculation (the counterpart
for the "normal" division). For divisors which are a power of 2, one can
efficiently use some bit fiddling to avoid the actual division for such
operations. This CL cleanly splits off these operations into separate
Lithium instructions, making the code much more maintainable and more
consistent across platforms.
There are 2 basic variations of these bit fiddling algorithms: One
involving branches and a seemingly more clever one without branches.
Choosing between the two is not as easy as it seems: Benchmarks (and
probably real-world) programs seem to favor positive dividends,
registers and shifting units are sometimes scarce resources, and branch
prediction is quite good in modern processors. Therefore only the
"normal" division by a power of 2 is implemented in a branch-free
manner, this seems to be the best approach in practice. If this turns
out to be wrong, we can easily and locally change this.
BUG=
R=plind44@gmail.com
Review URL: https://codereview.chromium.org/189433008
Patch from Balazs Kilvady <kilvadyb@homejinni.com>.
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19733 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Port r19706 (81fd8dd)
Original commit message:
We can make more efficient code to check against type cells in the future if we use symbols, guaranteed not to conflict with user code. Currently, the "symbols" are the hole and undefined. Undefined may come in from the outside.
BUG=
R=mvstanton@chromium.org
Review URL: https://codereview.chromium.org/189143006
Patch from Balazs Kilvady <kilvadyb@homejinni.com>.
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19726 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Notes about a few TODOs handled in this patch:
* In ProfileEntryHookStub::Generate:
Stubs are always called with relocation.
* In CreateArrayDispatchOneArgument:
The branches to registers can't be conditional. We could use a jump table, but
there are only 6 different kinds so it is likely not worth it.
* In Builtins::Generate_StringConstructCode:
Rename the argc register (x0) after its meaning changes.
Remove a TODO: using a macro would not make the code clearer.
* In Generate_JSEntryTrampolineHelper:
Remove the TODO and raise an internal issue to investigate this.
* In Disassembler::SubstituteBranchTargetField:
Print the target address, but we don't have more info on the target.
R=ulan@chromium.org
Review URL: https://codereview.chromium.org/185793002
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19724 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
When object is creating via native V8 API calls JS callstack is empty and the allocation is indistinguishable from say compiler allocations. This change adds a separate entry for such allocations.
Since FunctionInfo not necessarily corresponds to a heap object they are now referred to using their index in the list of all FunctionInfos.
BUG=chromium:277984
LOG=N
R=loislo@chromium.org, mstarzinger@chromium.org
Review URL: https://codereview.chromium.org/177203002
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19718 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Lithium currently supports 3 division-like operations on integral operands: "Normal" division (rounding towards zero), flooring division (rounding towards -Infinity) and modulus calculation (the counterpart for the "normal" division). For divisors which are a power of 2, one can efficiently use some bit fiddling to avoid the actual division for such operations. This CL cleanly splits off these operations into separate Lithium instructions, making the code much more maintainable and more consistent across platforms.
There are 2 basic variations of these bit fiddling algorithms: One involving branches and a seemingly more clever one without branches. Choosing between the two is not as easy as it seems: Benchmarks (and probably real-world) programs seem to favor positive dividends, registers and shifting units are sometimes scarce resources, and branch prediction is quite good in modern processors. Therefore only the "normal" division by a power of 2 is implemented in a branch-free manner, this seems to be the best approach in practice. If this turns out to be wrong, we can easily and locally change this.
R=bmeurer@chromium.org
Review URL: https://codereview.chromium.org/175143002
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19715 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This feature makes it possible to associate data with a script and get it back
when the script is compiled or when an event is handled. It was historically
used by Chromium Dev Tools, but not any more. It is not used by node.js.
Note: this has nothing to do with the preparse data, despite the confusing name.
The preparse data is passed as ScriptData*.
Note 2: This is the same as r19616 ( https://codereview.chromium.org/184403002/ )
with a unused variable fix in bootstrapper.cc.
R=svenpanne@chromium.org
BUG=
Review URL: https://codereview.chromium.org/185533014
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19702 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
When we set an out of bounds array index, the index might be so large that
it causes the array to go to dictionary mode. It's better to avoid
"learning" that this was a growing store in that case.
This fix also partially reverts a fix for bug 347543, as this fix is
comprehensive and satisfies that repro case as well (partial revert of
v19591).
BUG=349874
LOG=N
R=verwaest@chromium.org
Review URL: https://codereview.chromium.org/188643002
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19691 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
VPrintHelper would silently ignore the stream given to it if application is in GUI mode (no console is attached) and redirect output to the debugger via OutputDebugString.
Such redirection makes sense only if passed stream is either stderr or stdout. Don't redirect any other stream to the debugger.
Reorder clauses in VPrintHelper to make condition more readable.
BUG=
R=yangguo@chromium.org
Review URL: https://codereview.chromium.org/177413006
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19688 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
