This change introduces new intrinsics used to desugar async functions
in the Parser and the BytecodeGenerator, namely we introduce a new
%_AsyncFunctionEnter intrinsic that constructs the generator object
for the async function (and in the future will also create the outer
promise for the async function). This generator object is internal
and never escapes to user code, plus since async functions don't have
a "prototype" property, we can just a single map here instead of tracking
the prototype/initial_map on every async function. This saves one word
per async function plus one initial_map per async function that was
invoked at least once.
We also introduce two new intrinsics %_AsyncFunctionReject, which
rejects the outer promise with the caught exception, and another
%_AsyncFunctionResolve, which resolves the outer promise with the
right hand side of the `return` statement. These functions also perform
the DevTools part of the job (aka popping from the promise stack and
sending the debug event). This allows us to get rid of the implicit
try-finally from async functions completely; because the finally
block only called to the %AsyncFunctionPromiseRelease builtin, which
was used to inform DevTools.
In essence we now turn an async function like
```js
async function f(x) { return await bar(x); }
```
into something like this (in Parser and BytecodeGenerator respectively):
```
function f(x) {
.generator_object = %_AsyncFunctionEnter(.closure, this);
.promise = %AsyncFunctionCreatePromise();
try {
.tmp = await bar(x);
return %_AsyncFunctionResolve(.promise, .tmp);
} catch (e) {
return %_AsyncFunctionReject(.promise, e);
}
}
```
Overall the bytecode for async functions gets significantly shorter
already (and will get even shorter once we put the outer promise into
the async function generator object). For example the bytecode for a
simple async function
```js
async function f(x) { return await x; }
```
goes from 175 bytes to 110 bytes (a ~38% reduction in size), which
is in particular due to the simplification around the try-finally
removal.
Overall this seems to improve the doxbee-async-es2017-native test by
around 2-3%. On the test case mentioned in v8:8276 we go from
1124ms to 441ms, which corresponds to a 60% reduction in total
execution time!
Tbr: marja@chromium.org
Bug: v8:7253, v8:7522, v8:8276
Cq-Include-Trybots: luci.chromium.try:linux_chromium_headless_rel;luci.chromium.try:linux_chromium_rel_ng;master.tryserver.blink:linux_trusty_blink_rel
Change-Id: Id29dc92de7490b387ff697860c900cee44c9a7a4
Reviewed-on: https://chromium-review.googlesource.com/c/1269041
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Sathya Gunasekaran <gsathya@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Reviewed-by: Maya Lekova <mslekova@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56502}
Instead of requiring the pattern that a SuspendGenerator must be
followed by a Return, make SuspendGenerator return directly. This can,
in the future, simplify some of the reasoning around generator suspends.
Change-Id: I94c0156a89dc0e1c0bc306bc57acf766f3b4deb5
Reviewed-on: https://chromium-review.googlesource.com/857463
Reviewed-by: Georg Neis <neis@chromium.org>
Reviewed-by: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50748}
https://github.com/tc39/ecma262/pull/988 gained concensus during the
september 2017 TC39 meetings. This moves the load of the "next" method
to the very beginning of the iteration protocol, rather than during
each iteration step.
This impacts:
- yield*
- for-of loops
- spread arguments
- array spreads
In the v8 implementation, this also affects async iteration versions of
these things (the sole exception being the Async-From-Sync iterator,
which requires a few more changes to work with this, likely done in a
followup patch).
This change introduces a new AST node, ResolvedProperty, which can be used
as a callee by Call nodes to produce the same bytecode as Property calls,
without observably re-loading the property. This is used in several
AST-desugarings involving the iteration protocol.
BUG=v8:6861, v8:5699
R=rmcilroy@chromium.orgTBR=neis@chromium.org, adamk@chromium.org
Cq-Include-Trybots: luci.v8.try:v8_linux_noi18n_rel_ng
Change-Id: I9685db6e85315ba8a2df87a4537c2bf491e1e35b
Reviewed-on: https://chromium-review.googlesource.com/857593
Commit-Queue: Caitlin Potter <caitp@igalia.com>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50518}
This reverts commit bf4cc9ee15.
Reason for revert: Breaks windows with msvc and linux with gcc
https://build.chromium.org/p/client.v8/builders/V8%20Win64%20-%20msvc/builds/841https://build.chromium.org/p/client.v8/builders/V8%20Linux%20gcc%204.8/builds/17265
Original change's description:
> [esnext] load `iterator.next` only once at beginning of iteration
>
> https://github.com/tc39/ecma262/pull/988 gained concensus during the
> september 2017 TC39 meetings. This moves the load of the "next" method
> to the very beginning of the iteration protocol, rather than during
> each iteration step.
>
> This impacts:
>
> - yield*
> - for-of loops
> - spread arguments
> - array spreads
>
> In the v8 implementation, this also affects async iteration versions of
> these things (the sole exception being the Async-From-Sync iterator,
> which requires a few more changes to work with this, likely done in a
> followup patch).
>
> This change introduces a new AST node, ResolvedProperty, which can be used
> as a callee by Call nodes to produce the same bytecode as Property calls,
> without observably re-loading the property. This is used in several
> AST-desugarings involving the iteration protocol.
>
> BUG=v8:6861, v8:5699
> R=rmcilroy@chromium.org, neis@chromium.org, adamk@chromium.org
>
> Cq-Include-Trybots: luci.v8.try:v8_linux_noi18n_rel_ng
> Change-Id: Ib81106a0182687fc5efea0bc32302ad06376773b
> Reviewed-on: https://chromium-review.googlesource.com/687997
> Commit-Queue: Caitlin Potter <caitp@igalia.com>
> Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
> Reviewed-by: Adam Klein <adamk@chromium.org>
> Reviewed-by: Georg Neis <neis@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#50452}
TBR=rmcilroy@chromium.org,adamk@chromium.org,neis@chromium.org,caitp@igalia.com,caitp@chromium.org
Change-Id: I1797c0d596dfd6850d6f0f505f591a7a990dd1f1
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:6861, v8:5699
Cq-Include-Trybots: luci.v8.try:v8_linux_noi18n_rel_ng
Reviewed-on: https://chromium-review.googlesource.com/857616
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50454}
https://github.com/tc39/ecma262/pull/988 gained concensus during the
september 2017 TC39 meetings. This moves the load of the "next" method
to the very beginning of the iteration protocol, rather than during
each iteration step.
This impacts:
- yield*
- for-of loops
- spread arguments
- array spreads
In the v8 implementation, this also affects async iteration versions of
these things (the sole exception being the Async-From-Sync iterator,
which requires a few more changes to work with this, likely done in a
followup patch).
This change introduces a new AST node, ResolvedProperty, which can be used
as a callee by Call nodes to produce the same bytecode as Property calls,
without observably re-loading the property. This is used in several
AST-desugarings involving the iteration protocol.
BUG=v8:6861, v8:5699
R=rmcilroy@chromium.org, neis@chromium.org, adamk@chromium.org
Cq-Include-Trybots: luci.v8.try:v8_linux_noi18n_rel_ng
Change-Id: Ib81106a0182687fc5efea0bc32302ad06376773b
Reviewed-on: https://chromium-review.googlesource.com/687997
Commit-Queue: Caitlin Potter <caitp@igalia.com>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50452}
It will help us to preserve some scripts for user.
R=alph@chromium.orgTBR=jgruber@chromium.org
Bug: chromium:655701
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_chromium_rel_ng
Change-Id: I6d42434148c2d9eb41c3a2af906e8c14ccf8d9a9
Reviewed-on: https://chromium-review.googlesource.com/806741
Commit-Queue: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
Reviewed-by: Alexei Filippov <alph@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49913}
Nop bytecodes are required only for break locations in debugger. Since nop bytecode doesn't change program state we can remove all of them.
There are at least two changes which this CL produce:
- we don't provide break position when we load local variable (still provide when load variable from global),
- we don't provide break position for statements without actual break positions (e.g. "a;") - these expressions should be super rare and user always can set breakpoint before or after this statement.
More details in one pager: https://docs.google.com/a/google.com/document/d/1JXlQpfMa9vRojbE272b6GMBbrfh6m_00135iAUOJEz8/edit?usp=sharing
Bug: v8:6425
Change-Id: I4aee73d497a84f7b5d89caa6dda6d3060567dfda
Reviewed-on: https://chromium-review.googlesource.com/543161
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46742}
Goal of this CL: explicit return from non-async function has position after
return expression as return position (will unblock [1]).
BytecodeArrayBuilder has SetStatementPosition and SetExpressionPosition methods.
If one of these methods is called then next generated bytecode will get passed
position. It's general treatment for most cases.
Unfortunately it doesn't work for Returns:
- debugger requires source positions exactly on kReturn bytecode in stepping
implementation,
- BytecodeGenerator::BuildReturn and BytecodeGenerator::BuildAsyncReturn
generates more then one bytecode and general solution will put return position
on first generated bytecode,
- it's not easy to split BuildReturn function into two parts to allow something
like following in BytecodeGenerator::VisitReturnStatement since generated
bytecodes are actually controlled by execution_control().
..->BuildReturnPrologue();
..->SetReturnPosition(stmt);
..->Return();
In this CL we pass ReturnStatement through ExecutionControl and use it for
position when we emit return bytecode right here.
So this CL only will improve return position for returns inside of non-async
functions, I'll address async functions later.
[1] https://chromium-review.googlesource.com/c/543161/
Change-Id: Iede512c120b00c209990bf50c20e7d23dc0d65db
Reviewed-on: https://chromium-review.googlesource.com/560738
Commit-Queue: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46687}
This includes several changes. From most to least interesting:
- No longer implement AwaitExpressions using a do-expression.
- Reduces frame-size of async generators by not allocating temporary
variables to hold results of Await epxressions.
- Streamline and reduce generated bytecodes for Await.
- Debugger no longer emits a debug::kCallBreakLocation breakpoint for
the JS-builtin call performed for Await, and instead only emits such
a breakpoint if the operand of Await is actually a call.
- Push fewer parameters to Await* builtins, using the receiver for the
first parameter (possible now that the CallRuntime invocation not
part of the AST).
- Adds a new Await AST node. No new members or anything, but it seemed
palatable to avoid having `if (is_await())` in a number of
VisitSuspend functions.
BUG=v8:5855, v8:5099, v8:4483
R=rmcilroy@chromium.org, kozyatinskiy@chromium.org, yangguo@chromium.orgTBR=bmeurer@chromium.org
Change-Id: I9cd3fda99cd40295c04fdf1aea01b5d83fac6caf
Reviewed-on: https://chromium-review.googlesource.com/558806
Commit-Queue: Georg Neis <neis@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Reviewed-by: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46666}
BytecodeArrayBreakIterator doesn't iterate through locations in position() order. SkipToPosition is looking for closest break_index to passed one. So we should iterate through all breakable locations in function to get all of them.
R=jgruber@chromium.org
Bug: v8:6469
Change-Id: Ida0b849e9df40458a13e0a0f7af6a00349088228
Reviewed-on: https://chromium-review.googlesource.com/527135
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45765}
In current implementation in expressions like await foo() we have break location right after foo call and before actual await.
And we additionally have a lot of other statement locations because of do scope.
Let's move async debugging closer to sync debugging and introduce only one break location for await - before awaited function call.
Bug: v8:6425,v8:6162
Change-Id: I7568767856022c49101e7f3b7e39a2e401d21644
Reviewed-on: https://chromium-review.googlesource.com/514046
Reviewed-by: Marja Hölttä <marja@chromium.org>
Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Commit-Queue: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45625}
This CL improves break locations for expressions like 'var a = <expr>'. Without CL we use <expr> position as break location for initialization statement, with this CL we use position of first character after '=' as position.
Benefits (see test for details):
- only one break in expressions which includes mix of property lookup and calls, e.g. var p = Promise.resolve().then(x => x * 2),
- removed redundant break location for expressions like: let { x, y } = { x: 1, y: 2}.
TBR=dgozman@chromium.org,rmcilroy@chromium.org,machenbach@chromium.org,marja@chromium.org,kozyatinskiy@chromium.org,devtools-reviews@chromium.org,v8-reviews@googlegroups.com
# Not skipping CQ checks because original CL landed > 1 day ago.
Bug: v8:5909
Change-Id: Ie84fa79afeed09e28cf8478ba610a0cfbfdfc294
Reviewed-on: https://chromium-review.googlesource.com/518116
Commit-Queue: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
Reviewed-by: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45598}
This reverts commit 7a9cc70492.
Reason for revert: Changes layout tests:
https://build.chromium.org/p/client.v8.fyi/builders/V8-Blink%20Linux%2064/builds/15882
This is about:
inspector/sources/debugger/source-frame-inline-breakpoint-decorations.html
Original change's description:
> [inspector] moved var initialization break location before init expression
>
> This CL improves break locations for expressions like 'var a = <expr>'. Without CL we use <expr> position as break location for initialization statement, with this CL we use position of first character after '=' as position.
> Benefits (see test for details):
> - only one break in expressions which includes mix of property lookup and calls, e.g. var p = Promise.resolve().then(x => x * 2),
> - removed redundant break location for expressions like: let { x, y } = { x: 1, y: 2}.
>
> Bug: v8:5909
> Change-Id: I039d911903a2826c9859710a63ab0462c992e11b
> Reviewed-on: https://chromium-review.googlesource.com/513926
> Commit-Queue: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
> Reviewed-by: Marja Hölttä <marja@chromium.org>
> Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#45530}
TBR=dgozman@chromium.org,marja@chromium.org,kozyatinskiy@chromium.org
# Not skipping CQ checks because original CL landed > 1 day ago.
Bug: v8:5909
Change-Id: Ibf84401e8050d3c84db219d983de2c6bba0f697f
Reviewed-on: https://chromium-review.googlesource.com/518102
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45547}
This CL improves break locations for expressions like 'var a = <expr>'. Without CL we use <expr> position as break location for initialization statement, with this CL we use position of first character after '=' as position.
Benefits (see test for details):
- only one break in expressions which includes mix of property lookup and calls, e.g. var p = Promise.resolve().then(x => x * 2),
- removed redundant break location for expressions like: let { x, y } = { x: 1, y: 2}.
Bug: v8:5909
Change-Id: I039d911903a2826c9859710a63ab0462c992e11b
Reviewed-on: https://chromium-review.googlesource.com/513926
Commit-Queue: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
Reviewed-by: Marja Hölttä <marja@chromium.org>
Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45530}
There are two break locations at the same source location by desugaring:
- call iterator.next,
- before variable assignment.
Additionally location for for..of loops is moved from before "of" to before each variable expression.
We should not report first implicit call to avoid user confusion. User still able to go into .next function with both scenarios:
- when this call is reached by stepOver or stepInto from previous line,
- when this call is reached because of breakpoint at current line.
BUG=v8:6425
R=dgozman@chromium.org,jgruber@chromium.org
Review-Url: https://codereview.chromium.org/2893313002
Cr-Commit-Position: refs/heads/master@{#45509}
Split BytecodeGenerator::VisitSuspend into two pieces, one for
building the suspension code and one for resumption (these
are split into separate Build methods for convenience).
Each gets its own RegisterAllocationScope, which allows us to
reduce the register file size of the empty generator by 1.
For consistency, rename VisitGeneratorPrologue() to
BuildGeneratorPrologue() to match the names of the two
newly-created methods.
This relands the patch originally committed in
98927ea51b, as the test failure
due to that change was a code flushing bug. Code flushing was
disabled in de4a4095cf.
R=rmcilroy@chromium.org
Bug: v8:6379
Change-Id: Ifb4deafea99693c0a4e8646cf4e9884c7374cfc6
Reviewed-on: https://chromium-review.googlesource.com/508814
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45406}
This reverts commit 98927ea51b.
Reason for revert: Breaks Mac GC Stress bot.
https://uberchromegw.corp.google.com/i/client.v8/builders/V8%20Mac%20GC%20Stress/builds/13299/steps/Mjsunit/logs/for-await-of
Original change's description:
> [ignition] Be smarter about register allocation in VisitSuspend
>
> Split BytecodeGenerator::VisitSuspend into two pieces, one for
> building the suspension code and one for resumption (these
> are split into separate Build methods for convenience).
> Each gets its own RegisterAllocationScope, which allows us to
> reduce the register file size of the empty generator by 1.
>
> For consistency, rename VisitGeneratorPrologue() to
> BuildGeneratorPrologue() to match the names of the two
> newly-created methods.
>
> Bug: v8:6379
> Change-Id: I08a617a44f99706cfff09bf86fb0a25a9cd6e032
> Reviewed-on: https://chromium-review.googlesource.com/503593
> Commit-Queue: Adam Klein <adamk@chromium.org>
> Reviewed-by: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
> Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#45318}
TBR=rmcilroy@chromium.org,adamk@chromium.org,neis@chromium.org,kozyatinskiy@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
Bug: v8:6379
Change-Id: I787fc3811c4f33a8021cf9170d43a74ed9b55d1c
Reviewed-on: https://chromium-review.googlesource.com/506548
Reviewed-by: Deepti Gandluri <gdeepti@chromium.org>
Commit-Queue: Deepti Gandluri <gdeepti@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45319}
Split BytecodeGenerator::VisitSuspend into two pieces, one for
building the suspension code and one for resumption (these
are split into separate Build methods for convenience).
Each gets its own RegisterAllocationScope, which allows us to
reduce the register file size of the empty generator by 1.
For consistency, rename VisitGeneratorPrologue() to
BuildGeneratorPrologue() to match the names of the two
newly-created methods.
Bug: v8:6379
Change-Id: I08a617a44f99706cfff09bf86fb0a25a9cd6e032
Reviewed-on: https://chromium-review.googlesource.com/503593
Commit-Queue: Adam Klein <adamk@chromium.org>
Reviewed-by: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45318}
Removes the do-expression wrapping, modifies BytecodeGenerator change
to enter a class literal's block scope if needed.
This does not solve the actual bug in v8:6322, but helps mitigate it in
simple cases. The bug is caused by BytecodeGenerator not allocating a
large enough array of context registers to hold its entire stack,
allowing non-context registers to be overwritten during PushContext and
PopContext bytecodes.
Nevertheless, I like the idea of not depending on do-expressions when
possible, so I think it's worth doing anyways.
BUG=v8:6322
R=rmcilroy@chromium.org, marja@chromium.org, littledan@chromium.org
Change-Id: I82b7569db2a0eead1694bd04765fc4456c2f1a0a
Reviewed-on: https://chromium-review.googlesource.com/491074
Commit-Queue: Caitlin Potter <caitp@igalia.com>
Reviewed-by: Marja Hölttä <marja@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Daniel Ehrenberg <littledan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45110}
This CL provide type with each break location, type could be: call, return or debugger statement.
BUG=chromium:432469
R=yangguo@chromium.org,dgozman@chromium.org
Review-Url: https://codereview.chromium.org/2728563002
Cr-Commit-Position: refs/heads/master@{#43619}
