f435d6222f
Original commit message: [wasm] Introduce the TrapIf and TrapUnless operators to generate trap code. Some instructions in WebAssembly trap for some inputs, which means that the execution is terminated and (at least at the moment) a JavaScript exception is thrown. Examples for traps are out-of-bounds memory accesses, or integer divisions by zero. Without the TrapIf and TrapUnless operators trap check in WebAssembly introduces 5 TurboFan nodes (branch, if_true, if_false, trap-reason constant, trap-position constant), in addition to the trap condition itself. Additionally, each WebAssembly function has four TurboFan nodes (merge, effect_phi, 2 phis) whose number of inputs is linear to the number of trap checks in the function. Especially for functions with high numbers of trap checks we observe a significant slowdown in compilation time, down to 0.22 MiB/s in the sqlite benchmark instead of the average of 3 MiB/s in other benchmarks. By introducing a TrapIf common operator only a single node is necessary per trap check, in addition to the trap condition. Also the nodes which are shared between trap checks (merge, effect_phi, 2 phis) would disappear. First measurements suggest a speedup of 30-50% on average. This CL only implements TrapIf and TrapUnless on x64. The implementation is also hidden behind the --wasm-trap-if flag. Please take a special look at how the source position is transfered from the instruction selector to the code generator, and at the context that is used for the runtime call. R=titzer@chromium.org Review-Url: https://codereview.chromium.org/2571813002 Cr-Commit-Position: refs/heads/master@{#41735} |
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| gni | ||
| gypfiles | ||
| include | ||
| infra | ||
| samples | ||
| src | ||
| test | ||
| testing | ||
| third_party | ||
| tools | ||
| .clang-format | ||
| .gitignore | ||
| .gn | ||
| .ycm_extra_conf.py | ||
| AUTHORS | ||
| BUILD.gn | ||
| ChangeLog | ||
| CODE_OF_CONDUCT.md | ||
| codereview.settings | ||
| DEPS | ||
| LICENSE | ||
| LICENSE.fdlibm | ||
| LICENSE.strongtalk | ||
| LICENSE.v8 | ||
| LICENSE.valgrind | ||
| Makefile | ||
| Makefile.android | ||
| OWNERS | ||
| PRESUBMIT.py | ||
| README.md | ||
| snapshot_toolchain.gni | ||
| WATCHLISTS | ||
V8 JavaScript Engine
V8 is Google's open source JavaScript engine.
V8 implements ECMAScript as specified in ECMA-262.
V8 is written in C++ and is used in Google Chrome, the open source browser from Google.
V8 can run standalone, or can be embedded into any C++ application.
V8 Project page: https://github.com/v8/v8/wiki
Getting the Code
Checkout depot tools, and run
fetch v8
This will checkout V8 into the directory v8 and fetch all of its dependencies.
To stay up to date, run
git pull origin
gclient sync
For fetching all branches, add the following into your remote
configuration in .git/config:
fetch = +refs/branch-heads/*:refs/remotes/branch-heads/*
fetch = +refs/tags/*:refs/tags/*
Contributing
Please follow the instructions mentioned on the V8 wiki.