This implements correct semantics for "extensible" top level lexical scope.
The entire lexical scope is represented at runtime by GlobalContextTable, reachable from native context and accumulating global contexts from every script loaded into the context.
When the new script starts executing, it does the following validation:
- checks the GlobalContextTable and global object (non-configurable own) properties against the set of declarations it introduces and reports potential conflicts.
- invalidates the conflicting PropertyCells on global object, so that any code depending on them will miss/deopt causing any contextual lookups to be reexecuted under the new bindings
- adds the lexical bindings it introduces to the GlobalContextTable
Loads and stores for contextual lookups are modified so that they check the GlobalContextTable before looking up properties on global object, thus implementing the shadowing of global object properties by lexical declarations.
R=adamk@chromium.org, rossberg@chromium.org
Review URL: https://codereview.chromium.org/705663004
Cr-Commit-Position: refs/heads/master@{#25220}
git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@25220 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
The spec explicitly forbids them. V8 never handled them properly either, just
the Scanner accepted them (it had code to add them literally to the
LiteralBuffer) and later on, Regexp constructor disallowed them.
According to the spec, unicode escapes in regexp flags should be an early error
("It is a Syntax Error if IdentifierPart contains a Unicode escape sequence.").
Note that Scanner is still more relaxed about regexp flags than the
spec. Especially, it accepts any identifier parts (not just a small set of
letters) and doesn't check for duplicates.
R=rossberg@chromium.org
Review URL: https://codereview.chromium.org/700373003
Cr-Commit-Position: refs/heads/master@{#25215}
git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@25215 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
During generation code and relocation info are generated simultaneously.
When code generation is done you each code object has associated "relocation info".
Relocation information lets V8 to mark interesting places in the generated code: the pointers that might need to be relocated (after garbage collection),
correspondences between the machine program counter and source locations for stack walking.
This patch:
1. Add more source positions info in reloc info to make it suitable for source level mapping.
The amount of data should not be increased dramatically because (1) V8 already marks interesting places in the generated code and
(2) V8 does not write redundant information (it writes a pair (pc_offset, pos) only if pos is changed and skips other).
I measured it on Octane benchmark - for unoptimized code the number of source positions may achieve 2x ('lin_solve' from NavierStokes benchmark).
2. When a sample happens, CPU profiler finds a code object by pc, then use its reloc info to match the sample to a source line.
If a source line is found that hit counter is increased by one for this line.
3. Add a new public V8 API to get the hit source lines by CDT CPU profiler.
Note that it's expected a minor patch in Blink to pack the source level info in JSON to be shown.
4.Add a test that checks how the samples are distributed through source lines.
It tests two cases: (1) relocation info created during code generation and (2) relocation info associated with precompiled function's version.
Patch from Denis Pravdin <denis.pravdin@intel.com>;
R=svenpanne@chromium.org, yurys@chromium.org
Review URL: https://codereview.chromium.org/682143003
Patch from Weiliang <weiliang.lin@intel.com>.
Cr-Commit-Position: refs/heads/master@{#25182}
git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@25182 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This contains the following changes squashed together:
- Switch BasicBlock::loop_end to be a basic block instead of an RPO.
- Switch ScheduleLate to use dominator depth instead of RPO.
- Switch ScheduleEarly to use dominator depth instead of RPO.
- Push out absolute RPO ordering everywhere else in the scheduler.
- Keep linked list of blocks in RPO order while scheduling.
- Switch from RPO number to depth for dominator calculation.
R=jarin@chromium.org
Review URL: https://codereview.chromium.org/696363002
Cr-Commit-Position: refs/heads/master@{#25138}
git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@25138 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Not clearing can lead to a crash under following conditions:
1. Backing store of a weak map is allocated in large object space.
2. The backing store is marked incrementaly via the weak map.
3. The weak map is updated and gets a new backing store.
4. The store buffer overflows and marks the chunk of the old backing store as
"scan on scavenge."
5. Mark-compact collection kills some elements of the weak map. Note that the
old backing store survives because it was marked incrementally, but its dead
elements are not cleared.
6. Scavenger iterates over the old backing store, tries to move a dead object
and crashes.
BUG=v8:3631
LOG=N
TEST=cctest/test-heap/Regress3631
R=jkummerow@chromium.org
Review URL: https://codereview.chromium.org/686783003
Cr-Commit-Position: refs/heads/master@{#25032}
git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@25032 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This simplifies escape handling and makes it easier to extend escapes for ES6.
PushBack just before detecting ILLEGAL is unnecessary, since we will abort the
scanning / parsing anyway at that point, and it doesn't matter where the cursor
exactly is. The error messages w/ PushBack are not any better or more correct
than without.
In addition: remove a comment about handling invalid escapes gracefully when we
no longer do. (*)
This CL includes a behavioral change: For input "var r = /foobar/g\urrrr;" we
used to report "unexpected_token: ILLEGAL" for "\u", but now we report
malformed_regexp_flags which is a more correct error message. (Note that the
code for reporting invalid_regexp_flags was dead, and invalid_regexp_flags is
not the right error message.)
Note that the V8 is more relaxed about unicode escapes in regexp flags than ES6
(see
http://people.mozilla.org/~jorendorff/es6-draft.html#sec-regular-expressions )
and this CL doesn't change it. (V8 accepts any \uxxxx, ES6 spec says only a
certain value range is acceptable.)
(*) Code archaeology:
Originally, doing PushBack in ScanHexEscape made sense (see e.g., here
https://codereview.chromium.org/5063003/diff/6001/src/prescanner.h ), since we
wouldn't return ILLEGAL but treat an invalid escape sequence "\uxxxx" as
"uxxxx".
(The repo at that point contains another instance of the same function, from the
initial commit. The logic is the same.)
This behavior was changed in a "renaming" commit
https://codereview.chromium.org/7739020.
BUG=
R=rossberg@chromium.org
Review URL: https://codereview.chromium.org/684873002
Cr-Commit-Position: refs/heads/master@{#25031}
git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@25031 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
