- 10 Oct, 2018 1 commit
-
-
Benedikt Meurer authored
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}
-
- 22 Jan, 2018 1 commit
-
-
Leszek Swirski authored
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/857463Reviewed-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}
-
- 18 Jul, 2017 1 commit
-
-
Alexey Kozyatinskiy authored
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/543161Reviewed-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}
-
- 14 Jul, 2017 2 commits
-
-
Alexey Kozyatinskiy authored
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}
-
Caitlin Potter authored
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.org TBR=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}
-
- 31 May, 2017 1 commit
-
-
Alexey Kozyatinskiy authored
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/514046Reviewed-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}
-