Preparsing is always maximally lazy (every function that can be lazy is preparsed
lazily), but Parser has more complicated laziness logic.
If we're going to parse eagerly, and we have preparse data from lazy preparsing,
we're gonna have a bad time. The symbol stream won't contain symbols inside lazy
functions, and when the Parser parses them eagerly, it will consume symbols from
the symbol stream, and everything will go wrong.
This bug was hidden because the symbol cache was not used for real (see
https://codereview.chromium.org/172753002/ ).
R=ulan@chromium.org
BUG=346207
LOG=Y
Review URL: https://codereview.chromium.org/177973002
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19532 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
The Parser never used the symbol stream produced by the PreParser for anything
useful, due to a bug introduced 3.5 years ago by
https://codereview.chromium.org/3356010/diff/7001/src/parser.cc.
The bug is that calling Initialize on symbol_cache_ doesn't change its
length. So the length remains 0, and the "if" in Parser::LookupSymbol is always
true, and Parser::LookupCachedSymbol is never called and symbol_cache_ never
filled.
This bug also masked a bug that the symbol stream produced by PreParser doesn't
match what Parser wants to consume. The repro case is the following:
var myo = {if: 4}; print(myo.if);
PreParser doesn't log a symbol for the first "if", but in the corresponding
place, Parser consumes one symbol from the symbol stream. Since the consumed
symbols were never really used, this mismatch went unnoticed.
This CL also fixes that bug.
BUG=
R=ulan@chromium.org
Review URL: https://codereview.chromium.org/172753002
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19505 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Refresh the implementation of Symbols to catch up with what the
specification now mandates:
* The global Symbol() function manufactures new Symbol values,
optionally with a string description attached.
* Invoking Symbol() as a constructor will now throw.
* ToString() over Symbol values still throws, and
Object.prototype.toString() stringifies like before.
* A Symbol value is wrapped in a Symbol object either implicitly if
it is the receiver, or explicitly done via Object(symbolValue) or
(new Object(symbolValue).)
* The Symbol.prototype.toString() method no longer throws on Symbol
wrapper objects (nor Symbol values.) Ditto for Symbol.prototype.valueOf().
* Symbol.prototype.toString() stringifies as "Symbol("<description>"),
valueOf() returns the wrapper's Symbol value.
* ToPrimitive() over Symbol wrapper objects now throws.
Overall, this provides a stricter separation between Symbol values and
wrapper objects than before, and the explicit fetching out of the
description (nee name) via the "name" property is no longer supported
(by the spec nor the implementation.)
Adjusted existing Symbol test files to fit current, adding some extra
tests for new/changed behavior.
LOG=N
R=arv@chromium.org, rossberg@chromium.org, arv, rossberg
BUG=v8:3053
Review URL: https://codereview.chromium.org/118553003
Patch from Sigbjorn Finne <sigbjornf@opera.com>.
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19490 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This addresses several TODOs:
- Push and Pop requests can be queued up so that arrays of Registers
can be pushed efficiently, with just one PrepareForPush/Pop.
- PushMultipleTimes now takes an Operand. This allows variable-length
arguments arrays to be initialized, for example.
- A NoUseRealAbortsScope has been added to Abort so that
AssertStackConsistency can be called from PrepareForPush without
introducing infinite recursion.
BUG=
R=rmcilroy@chromium.org, ulan@chromium.org
Review URL: https://codereview.chromium.org/170623002
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19474 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Code generation would fail when assembling a branch to a label that is bound
outside the immediate range of the instruction. A64 is sensitive to this, as the
various branching instructions have different ranges, going down to +-32KB for
TBZ/TBNZ. The MacroAssembler is augmented to handle branches to targets that
may exceed the immediate range of instructions.
When branching backward to a label exceeding the instruction range, the
MacroAssembler can simply tweak the generated code to use an unconditional
branch with a longer range. For example instead of
B(cond, &label);
the MacroAssembler can generate:
b(InvertCondition(cond), &done);
b(&label);
bind(&done);
Since the target is not known when the branch is emitted, forward branches uses
a different mechanism. The MacroAssembler keeps track of forward branches to
unbound labels. When the code generation approaches the end of the range of a
branch, a veneer is generated for the branch.
BUG=v8:3148
LOG=Y
R=ulan@chromium.org
Review URL: https://codereview.chromium.org/169893002
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19444 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Arithmetic right shifting is *not* division in two's complement
representation, only in one's complement. So we convert to one's
complement, shift, and go back to two's complement. By permutating the
last steps, one can get efficient branch-free code. This insight comes
from the paleozoic era of computer science, see the paper from 1976:
Guy Lewis Steele Jr.: "Arithmetic Shifting Considered Harmful"
ftp://publications.ai.mit.edu/ai-publications/pdf/AIM-378.pdf
This results in better and more correct code than our previous
"neg/shift/neg" dance.
LOG=y
BUG=v8:3151
R=bmeurer@chromium.org
Review URL: https://codereview.chromium.org/166793002
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19434 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Notes:
- We use simple recursion to keep track of how many "new" operators we have seen
and where.
- This makes the self-baked stack class PositionStack in parser.cc unnecessary.
- Now the logic is also unified between Parser and PreParser.
- This is a fixed version of r19386.
R=ulan@chromium.org
BUG=v8:3126
LOG=N
Review URL: https://codereview.chromium.org/168583008
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19417 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
