Commit Graph

738 Commits

Author SHA1 Message Date
rmcilroy
03369ed2cb [Interpreter] Add support for short (16 bit) operands.
Adds support for short operands, starting with kIdx16. Introduces
BytecodeTraits to enable compile time determination of various traits for a
bytecode, such as size, operands, etc. Reworks BytecodeIterator,
BytecodeArrayBuilder and Bytecodes::Decode to support 16 bit operands. Adds
support to Interpreter to load 16 bit operands.

Also fixes a bug with ToBoolean where it wouldn't get emitted at the start
of a block, and added a test.

BytecodeTraits template magic inspired by oth@chromium.org.

BUG=v8:4280
LOG=N

Review URL: https://codereview.chromium.org/1370893002

Cr-Commit-Position: refs/heads/master@{#31058}
2015-10-01 17:23:14 +00:00
oth
a7e16e5132 [Interpreter] Add for/while/do support to the bytecode generator.
Improve bytecode generation for if when there's no else clause.

Display target addresses for jump instructions in
Bytecode::Disassemble().

BUG=v8:4280
LOG=N

Review URL: https://codereview.chromium.org/1373903005

Cr-Commit-Position: refs/heads/master@{#31052}
2015-10-01 15:04:27 +00:00
dusan.m.milosavljevic
8bd431de92 MIPS64: Add big-endian support for mips64.
TEST=
BUG=

Review URL: https://codereview.chromium.org/1334793004

Cr-Commit-Position: refs/heads/master@{#31011}
2015-09-29 17:23:55 +00:00
alph
e0606c9f00 Move heap and CPU profilers into a dedicated directory.
Drive-by: remove unnecessary includes.

Review URL: https://codereview.chromium.org/1356223004

Cr-Commit-Position: refs/heads/master@{#30987}
2015-09-28 19:34:18 +00:00
oth
17363fa4f3 [Interpreter] Add interpreter support for compare ops and ToBoolean.
The comparison operators and ToBoolean are implemented by calling into
the runtime. There are new runtime methods are prefixed with Interpreter
to make use case clear.

BUG=v8:4280
LOG=N

Review URL: https://codereview.chromium.org/1369123002

Cr-Commit-Position: refs/heads/master@{#30983}
2015-09-28 18:07:05 +00:00
ulan
6256dc53cc Perform scavenge in idle tasks.
BUG=chromium:490559
LOG=NO

Review URL: https://codereview.chromium.org/1352453004

Cr-Commit-Position: refs/heads/master@{#30944}
2015-09-25 14:49:23 +00:00
danno
3ac27431a9 Revert of Remove register index/code indirection (patchset #17 id:320001 of https://codereview.chromium.org/1287383003/ )
Reason for revert:
Failures on greedy RegAlloc, Fuzzer

Original issue's description:
> Remove register index/code indirection
>
> Previous to this patch, both the lithium and TurboFan register
> allocators tracked allocated registers by "indices", rather than
> the register codes used elsewhere in the runtime. This patch
> ensures that codes are used everywhere, and in the process cleans
> up a bunch of redundant code and adds more structure to how the
> set of allocatable registers is defined.
>
> Some highlights of changes:
>
> * TurboFan's RegisterConfiguration class moved to V8's top level
>   so that it can be shared with Crankshaft.
> * Various "ToAllocationIndex" and related methods removed.
> * Code that can be easily shared between Register classes on
>   different platforms is now shared.
> * The list of allocatable registers on each platform is declared
>   as a list rather than implicitly via the register index <->
>   code mapping.
>
> Committed: https://crrev.com/80bc6f6e11f79524e3f1ad05579583adfd5f18b2
> Cr-Commit-Position: refs/heads/master@{#30913}

TBR=akos.palfi@imgtec.com,bmeurer@chromium.org,jarin@chromium.org,paul.lind@imgtec.com,titzer@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Review URL: https://codereview.chromium.org/1365073002

Cr-Commit-Position: refs/heads/master@{#30914}
2015-09-24 13:39:03 +00:00
danno
80bc6f6e11 Remove register index/code indirection
Previous to this patch, both the lithium and TurboFan register
allocators tracked allocated registers by "indices", rather than
the register codes used elsewhere in the runtime. This patch
ensures that codes are used everywhere, and in the process cleans
up a bunch of redundant code and adds more structure to how the
set of allocatable registers is defined.

Some highlights of changes:

* TurboFan's RegisterConfiguration class moved to V8's top level
  so that it can be shared with Crankshaft.
* Various "ToAllocationIndex" and related methods removed.
* Code that can be easily shared between Register classes on
  different platforms is now shared.
* The list of allocatable registers on each platform is declared
  as a list rather than implicitly via the register index <->
  code mapping.

Review URL: https://codereview.chromium.org/1287383003

Cr-Commit-Position: refs/heads/master@{#30913}
2015-09-24 12:53:13 +00:00
adamk
7462e99667 Remove on-by-default flag --harmony-object
It's been enabled since M45, which is now well into its stable period,
with no problems reported.

Review URL: https://codereview.chromium.org/1356793002

Cr-Commit-Position: refs/heads/master@{#30835}
2015-09-18 18:37:57 +00:00
hpayer
064be4c296 [heap] Move slots buffer into a separate file.
BUG=

Review URL: https://codereview.chromium.org/1343043002

Cr-Commit-Position: refs/heads/master@{#30746}
2015-09-15 12:35:20 +00:00
mstarzinger
ea25bf05f8 [heap] Separate scavenger functionality into own file.
This moves scavenging functionality into a separate component so that
neither the scavenger nor objects-visiting need to be exposed outside
the heap.

R=hpayer@chromium.org,mlippautz@chromium.org

Review URL: https://codereview.chromium.org/1323993004

Cr-Commit-Position: refs/heads/master@{#30712}
2015-09-14 11:44:30 +00:00
mvstanton
18bba7cb41 Vector ICs: gyp flag to run with vector-stores on.
This is so we can build with the flag on in the snapshot.
D8 then needs to be run with --vector-stores.

BUG=
R=machenbach@chromium.org

Review URL: https://codereview.chromium.org/1339593002

Cr-Commit-Position: refs/heads/master@{#30692}
2015-09-11 10:00:17 +00:00
oth
8df7b4f6b5 [Interpreter] Skeleton bytecode graph builder
Add skeleton version bytecode-graph-builder.{h,cc} for existing
bytecodes.

BUG=v8:4280
LOG=N

Review URL: https://codereview.chromium.org/1291693004

Cr-Commit-Position: refs/heads/master@{#30687}
2015-09-10 16:21:40 +00:00
bmeurer
a1b2ec60b0 [runtime] Move binary operator fallbacks into the runtime.
Replace the ADD, SUB, etc. builtins with proper runtime implementations,
and expose them as runtime calls that can be used by the code stubs and
the interpreter (for now).

Also remove all the support runtime functions for ADD, SUB and friends,
namely %NumberAdd, %NumberSub, and so on.

R=mstarzinger@chromium.org
CQ_INCLUDE_TRYBOTS=tryserver.v8:v8_linux_layout_dbg,v8_linux_nosnap_dbg

Review URL: https://codereview.chromium.org/1333843002

Cr-Commit-Position: refs/heads/master@{#30680}
2015-09-10 13:04:33 +00:00
ulan
057514d3fa Use idle task to perform incremental marking steps.
This moves incremental marking steps from gc-idle-time-handler and heap to the new incremental marking task.

BUG=chromium:490559
LOG=NO

Review URL: https://codereview.chromium.org/1265423002

Cr-Commit-Position: refs/heads/master@{#30641}
2015-09-08 15:54:37 +00:00
vogelheim
244cc0a6a9 Remove all gyp BUILD rules with multiple outputs.
- Modify js2c to accept --js and --nojs,
- modify mksnapshot to accept --startup_src
  (instead of a positional parameter, so that it can be omitted),
- modify v8.gyp to use the above so that no target has multiple
  output dependencies, and
- update GN to use the switches above.

(I have not succeeded in fixing the GYP->make translator to properly map
 multi-output rules, so that they work as expected in all edge cases.
 This CL signals defeat on that front, and instead I rewrite the GYP
 file to avoid that situation in the first place.)

R=jochen@chromium.org
BUG=v8:4382
LOG=N

Review URL: https://codereview.chromium.org/1310273009

Cr-Commit-Position: refs/heads/master@{#30640}
2015-09-08 15:24:53 +00:00
fedor
c7392f2e41 [heap] introduce ArrayBufferTracker
Move various ArrayBuffer-related methods from Heap class to the newly
created ArrayBufferTracker. Consolidate and simplify things!

BUG=
R=mlippautz@chromium.org

Review URL: https://codereview.chromium.org/1324023007

Cr-Commit-Position: refs/heads/master@{#30624}
2015-09-07 19:38:30 +00:00
mlippautz
47d42a9ac1 Adds atomic utilities (based on raw atomic operations) for your convenience:
{AtomicValue}: A simple integer value that can be atomically
read/set/incremented.

{AtomicEnumSet}: Similar to EnumSet this set basically represents an atomic
bitfield based on enums. Atomic operations guarantee that setting one bit does
not race with setting other bits.

{AtomicEnumFlag}: A flag that is based on an enum that can be read and
(attempted to be) changed atomically.

BUG=chromium:524425
LOG=N

Review URL: https://codereview.chromium.org/1310993004

Cr-Commit-Position: refs/heads/master@{#30560}
2015-09-03 12:54:34 +00:00
mstarzinger
c7de3e7f27 [heap] Separate ObjectStats out into its own class.
Note that this is only pulling out the bookkeeping side of things, the
marking visitor that actually records the statistics should also move
into the ObjectStats class. That will be done as a follow-up.

R=mlippautz@chromium.org

Review URL: https://codereview.chromium.org/1326793002

Cr-Commit-Position: refs/heads/master@{#30547}
2015-09-02 16:43:40 +00:00
bradnelson
546d9a70ac Add asm.js typer / validator.
Walk asm.js module ASTs, attach concrete type information
in preparation for generating a WASM module.

cctest test coverage (mjsunit coming in later CL).
Expressions, function tables, and foreign functions have coverage.
Statement coverage to be expanded in a later CL.

BUG= https://code.google.com/p/v8/issues/detail?id=4203
TEST=test-asm-validator
R=rossberg@chromium.org,titzer@chromium.org
LOG=N

Review URL: https://codereview.chromium.org/1322773002

Cr-Commit-Position: refs/heads/master@{#30520}
2015-09-01 18:30:43 +00:00
mstarzinger
5f57ebe222 Make isolate.h usable without objects-inl.h header.
This CL us a pure refactoring that makes an empty compilation unit
including just "isolate.h" or "contexts.h" but not "objects-inl.h"
compile without warnings or errors. This is needed to further reduce
the header dependency tangle.

R=bmeurer@chromium.org

Review URL: https://codereview.chromium.org/1322883002

Cr-Commit-Position: refs/heads/master@{#30500}
2015-09-01 09:25:27 +00:00
mstarzinger
3d7a34b5c7 [heap] Move IdentityMap data structure out of heap.
This data structure uses the public heap API only and is not specific
to any heap internals. It should be usable throughout V8 and inclusion
of the header file should not be restricted.

R=titzer@chromium.org

Review URL: https://codereview.chromium.org/1320503004

Cr-Commit-Position: refs/heads/master@{#30443}
2015-08-28 13:01:08 +00:00
bradnelson
e2b3edbf31 Spliting out TyperCache into ZoneTypeCache to share with AsmTyper.
The zone type cache would be handy inside the asm.js typer.
Pulling it out into a seperate inlinable header to allow sharing.

BUG=https://code.google.com/p/v8/issues/detail?id=4203
TEST=None
R=andreas@chromium.org,titzer@chromium.org
LOG=N

Review URL: https://codereview.chromium.org/1307093006

Cr-Commit-Position: refs/heads/master@{#30398}
2015-08-26 21:41:05 +00:00
mtrofin
5d954d6506 [turbofan] Deferred blocks splintering.
This change encompasses what is necessary to enable stack checks in loops without suffering large regressions.

Primarily, it consists of a new mechanism for dealing with deferred blocks by "splintering", rather than splitting, inside deferred blocks.

My initial change was splitting along deferred block boundaries, but the regression introduced by stackchecks wasn't resolved conclusively. After investigation, it appears that just splitting ranges along cold block boundaries leads to a greater opportunity for moves on the hot path, hence the suboptimal outcome.

The alternative "splinters" ranges rather than splitting them. While splitting creates 2 ranges and links them (parent-child), in contrast, splintering creates a new independent range with no parent-child relation to the original. The original range appears as if it has a liveness hole in the place of the splintered one. All thus obtained ranges are then register allocated with no change to the register allocator.

The splinters (cold blocks) do not conflict with the hot path ranges, by construction. The hot path ones have less pressure to split, because we remove a source of conflicts. After allocation, we merge the splinters back to their original ranges and continue the pipeline. We leverage the previous changes made for deferred blocks (determining where to spill, for example).

Review URL: https://codereview.chromium.org/1305393003

Cr-Commit-Position: refs/heads/master@{#30357}
2015-08-25 14:47:38 +00:00
bradnelson
10f2c5c33a Adding visitors to regurgitate expression types or reset them.
Adding an AstExpressionVisitor to touch each expression node in
an AST.

Adding TypingReseter to clear the slate after a failed asm.js
validation that has set partial typing information.

Adding a ExpressionTypeCollector to walk the expressions
in an AST and emit them as a string for testing.

Adding tests of the above.

LOG=N
BUG= https://code.google.com/p/v8/issues/detail?id=4203
TEST=test-typing-reset,test-ast-expression-visitor
R=rossberg@chromium.org,titzer@chromium.org

Review URL: https://codereview.chromium.org/1288773007

Cr-Commit-Position: refs/heads/master@{#30336}
2015-08-24 17:16:49 +00:00
mstarzinger
8c70c20568 Remove code.h header and move ParameterCount class.
R=bmeurer@chromium.org

Review URL: https://codereview.chromium.org/1302293002

Cr-Commit-Position: refs/heads/master@{#30291}
2015-08-21 10:25:21 +00:00
mstarzinger
4e39437a02 Separate UnicodeCache out into an own file.
This make inclusion of unicode-inl.h in object.h absolete. Now most
compilation units don't require that header. It also breaks a cycle
within declarations of the scanner.h header.

This tries to remove includes of "-inl.h" headers from normal ".h"
headers, thereby reducing the chance of any cyclic dependencies and
decreasing the average size of our compilation units.

Note that this change still leaves 3 violations of that rule in the
code, checked with the "tools/check-inline-includes.sh" tool.

R=yangguo@chromium.org

Review URL: https://codereview.chromium.org/1287893006

Cr-Commit-Position: refs/heads/master@{#30268}
2015-08-20 11:47:09 +00:00
domenic
6f582f088a Add experimental, non-snapshotted V8 extras
Embedders would use these for features which must be able to be turned
off at runtime, despite being compiled into V8. They can be turned on
and off by the embedder using the --experimental_extras flag, e.g. via
v8::SetFlagsFromString.

R=yangguo@chromium.org, mlippautz@chromium.org, hpayer@chromium.org
BUG=chromium:507137
LOG=Y

Review URL: https://codereview.chromium.org/1284413002

Cr-Commit-Position: refs/heads/master@{#30260}
2015-08-20 00:01:14 +00:00
mstarzinger
e1ad02375a Remove empty string-search.cc file.
R=titzer@chromium.org

Review URL: https://codereview.chromium.org/1295333002

Cr-Commit-Position: refs/heads/master@{#30234}
2015-08-18 18:18:22 +00:00
bradnelson
a2462683b7 Allowing optional build of a WASM prototype behind a gyp define.
Place a copy of the v8-native-prototype in third_party/wasm.
GYP_DEFINES='v8_wasm=1' gclient runhooks

BUG=None
TEST=None
R=titzer@chromium.org
LOG=N

Review URL: https://codereview.chromium.org/1294543006

Cr-Commit-Position: refs/heads/master@{#30225}
2015-08-18 15:04:11 +00:00
danno
cbbaf9ea6a [turbofan] Unify referencing of stack slots
Previously, it was not possible to specify StackSlotOperands for all
slots in both the caller and callee stacks. Specifically, the region
of the callee's stack including the saved return address, frame
pointer, function pointer and context pointer could not be addressed
by the register allocator/gap resolver.

In preparation for better tail call support, which will use the gap
resolver to reconcile outgoing parameters, this change makes it
possible to address all slots on the stack, because slots in the
previously inaccessible dead zone may become parameter slots for
outgoing tail calls. All caller stack slots are accessible as they
were before, with slot -1 corresponding to the last stack
parameter. Stack slot indices >= 0 access the callee stack, with slot
0 corresponding to the callee's saved return address, 1 corresponding
to the saved frame pointer, 2 corresponding to the current function
context, 3 corresponding to the frame marker/JSFunction, and slots 4
and above corresponding to spill slots.

The following changes were specifically	needed:

* Frame	has been changed to explicitly manage three areas of the
  callee frame, the fixed header, the spill slot area, and the
  callee-saved register area.
* Conversions from stack slot indices to fp offsets all now go through
  a common bottleneck: OptimizedFrame::StackSlotOffsetRelativeToFp
* The generation of deoptimization translation tables has been changed
  to support the new stack slot indexing scheme. Crankshaft, which
  doesn't support the new slot numbering in its register allocator,
  must adapt the indexes when creating translation tables.
* Callee-saved parameters are now kept below spill slots, not above,
  to support saving only the optimal set of used registers, which is
  only known after register allocation is finished and spill slots
  have been allocated.

Review URL: https://codereview.chromium.org/1261923007

Cr-Commit-Position: refs/heads/master@{#30224}
2015-08-18 14:48:11 +00:00
mstarzinger
366262e606 Remove inline header includes from natives.h header.
R=yangguo@chromium.org

Review URL: https://codereview.chromium.org/1303463002

Cr-Commit-Position: refs/heads/master@{#30222}
2015-08-18 14:31:34 +00:00
oth
238397c108 [Interpreter] Minimal bytecode generator.
Bytecode generator for local assignment and basic binary operations.

Command-line flag for printing bytecodes.

BUG=v8:4280
LOG=N

Review URL: https://codereview.chromium.org/1294543002

Cr-Commit-Position: refs/heads/master@{#30221}
2015-08-18 13:46:57 +00:00
yangguo
f3059c43a4 Native context: run prologue.js before runtime.js
R=mvstanton@chromium.org

Review URL: https://codereview.chromium.org/1294803004

Cr-Commit-Position: refs/heads/master@{#30217}
2015-08-18 11:15:50 +00:00
vogelheim
c69e2eae54 Rework startup-data-util.
- Make the API look like v8::V8::InitializeICU.
  (That is: A static method call, not an object to be created on the stack.)
- Fix path separator on Windows, by calling base::OS::isPathSeparator.
- Move into API, so that it can be called by hello-world & friends.
- Actually call it from hello-world and friends.

R=jochen@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1292053002

Cr-Commit-Position: refs/heads/master@{#30174}
2015-08-14 12:11:46 +00:00
yangguo
67e4b3732a Move regexp implementation into its own folder.
Review URL: https://codereview.chromium.org/1285163003

Cr-Commit-Position: refs/heads/master@{#30144}
2015-08-13 06:55:36 +00:00
yangguo
5df7d689eb Debugger: load debugger builtins as normal native JS.
R=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/1282793002

Cr-Commit-Position: refs/heads/master@{#30136}
2015-08-12 14:22:22 +00:00
titzer
7a222c612d [turbofan] Remove architecture-specific linkage files and LinkageTraits. Use macro-assembler-defined constants.
R=mstarzinger@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1272883003

Cr-Commit-Position: refs/heads/master@{#30063}
2015-08-07 10:45:43 +00:00
mstarzinger
325257744f Helpful checks.cc file is being helpful.
R=titzer@chromium.org

Review URL: https://codereview.chromium.org/1276843004

Cr-Commit-Position: refs/heads/master@{#30046}
2015-08-06 13:33:45 +00:00
yangguo
0a1a714f7e Introduce object visitor to estimate the size of a native context.
This is only an estimate since it counts objects that could be shared,
for example strings, cow arrays, heap numbers, etc.

It however ignores objects that could be shared, but may only be used
by the context to be measured, for example shared function infos,
script objects, scope infos, etc.

R=jochen@chromium.org

Review URL: https://codereview.chromium.org/1268333004

Cr-Commit-Position: refs/heads/master@{#30029}
2015-08-05 14:07:33 +00:00
adamk
2e4efcfac2 Add a --harmony-object-observe runtime flag (on by default)
To avoid tanking context startup performance, only the actual installation of the
JS-exposed API is flag-guarded. The remainder of the implementation still
resides in the snapshot.

Review URL: https://codereview.chromium.org/1257063003

Cr-Commit-Position: refs/heads/master@{#30017}
2015-08-04 20:53:32 +00:00
mtrofin
c11ab6f7e5 Setting up the stage for heuristics that preprocess live ranges before register allocation, and are independent of register allocation - e.g. the deferred blocks heuristic, or the split at call sites heuristic.
Added a separate flag for this, since we intend to enable it for the linear allocator as well. Currently, the option is "on" for greedy, as a point in time to enable its testing (through the greedy allocator bots).

BUG=

Review URL: https://codereview.chromium.org/1256313003

Cr-Commit-Position: refs/heads/master@{#30005}
2015-08-04 14:50:05 +00:00
yangguo
4e036f3042 Debugger: refactor ScopeIterator, FrameInspector and DebugEvaluate.
This is a pure refactor and does not change functionality.

R=ulan@chromium.org

Review URL: https://codereview.chromium.org/1264993002

Cr-Commit-Position: refs/heads/master@{#29995}
2015-08-04 12:10:13 +00:00
oth
6ab1f70e12 [Intepreter] BytecodeArrayBuilder and accumulator based bytecodes.
The BytecodeArrayBuilder has responsibility for emitting the BytecodeArray. It will be used by the AST walker.

Bytecode now uses an accumulator plus registers rather being pure register based.

Update BytecodeArray::Disassemble to print operand information.

BUG=v8:4280
LOG=N

Review URL: https://codereview.chromium.org/1266713004

Cr-Commit-Position: refs/heads/master@{#29970}
2015-08-03 10:42:30 +00:00
yangguo
1667c15e37 Debugger: move implementation to a separate folder.
R=cbruni@chromium.org

Review URL: https://codereview.chromium.org/1265923002

Cr-Commit-Position: refs/heads/master@{#29951}
2015-07-31 11:08:15 +00:00
titzer
c215c9569e [turbofan] Factor C call descriptor building into compiler/c-linkage.cc.
This is the first step in cutting the Gordian linkage/linkage-impl knot.

This basically changes the axis along which we organize call descriptor
building logic from having platform-specific files dedicated to all call
descriptor types to having call-descriptor-type-specific files that have

The next step is to factor the JS, code stub, and runtime call descriptors
similarly, dumping them into:
  compiler/js-linkage.cc
  compiler/runtime-linkage.cc
  compiler/code-stub-linkage.cc

 or, alternatively, all of them just into compiler/js-linkage.cc.

This also anticipates a wasm-linkage.cc file in the future.

R=bmeurer@chromium.org,danno@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1266603002

Cr-Commit-Position: refs/heads/master@{#29931}
2015-07-30 12:36:29 +00:00
yangguo
3be39a24bf Move Full-codegen into its own folder.
R=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/1248443003

Cr-Commit-Position: refs/heads/master@{#29840}
2015-07-24 10:11:57 +00:00
rmcilroy
7877c4e0c7 [interpreter] Add basic framework for bytecode handler code generation.
Adds basic support for generation of interpreter bytecode handler code
snippets. The InterpreterAssembler class exposes a set of low level,
interpreter specific operations which can be used to build a Turbofan
graph. The Interpreter class generates a bytecode handler snippet for
each bytecode by assembling operations using an InterpreterAssembler.

Currently only two simple bytecodes are supported: LoadLiteral0 and Return.

BUG=v8:4280
LOG=N

Review URL: https://codereview.chromium.org/1239793002

Cr-Commit-Position: refs/heads/master@{#29814}
2015-07-23 14:21:39 +00:00
mstarzinger
0788c98d3b [turbofan] Remove bloated GraphBuilder base class.
Using the GraphBuilder base class forces each node creation to go
through a virtual function dispatch just for the sake of saving the
duplication of the NewNode helper methods. In total that added up to
saving minus (sic!) six lines of code.

R=titzer@chromium.org

Review URL: https://codereview.chromium.org/1252093002

Cr-Commit-Position: refs/heads/master@{#29799}
2015-07-23 08:25:40 +00:00
danno
cca5e74a58 [turbofan]: Add a context relaxation Reducer
In many cases, the context that TurboFan's ASTGraphBuilder or subsequent
reduction operations attaches to nodes does not need to be that exact
context, but rather only needs to be one with the same native context,
because it is used internally only to fetch the native context, e.g. for
creating and throwing exceptions.

This reducer recognizes common cases where the context that is specified
for a node can be relaxed to a canonical, less specific one. This
relaxed context can either be the enclosing function's context or a specific
Module or Script context that is explicitly created within the function.

This optimization is especially important for TurboFan-generated code stubs
which use context specialization and inlining to generate optimal code.
Without context relaxation, many extraneous moves are generated to pass
exactly the right context to internal functions like ToNumber and
AllocateHeapNumber, which only need the native context. By turning context
relaxation on, these moves disappear because all these common internal
context uses are unified to the context passed into the stub function, which
is typically already in the correct context register and remains there for
short stubs. It also eliminates the explicit use of a specialized context
constant in the code stub in these cases, which could cause memory leaks.

Review URL: https://codereview.chromium.org/1244583003

Cr-Commit-Position: refs/heads/master@{#29763}
2015-07-20 17:16:14 +00:00