Ross McIlroy dd6c953601 Revert "[csa] verify skipped write-barriers in MemoryOptimizer" ... This reverts commit da7322c05f. Reason for revert: Breaking the pointer compression bots, e.g.: https://ci.chromium.org/p/v8/builders/ci/V8%20Linux64%20-%20pointer%20compression/3047 Original change's description: > [csa] verify skipped write-barriers in MemoryOptimizer > > With very few exceptions, this verifies all skipped write-barriers in > CSA and Torque, showing that the MemoryOptimizer together with some > type information on the stored value are enough to avoid unsafe skipped > write-barriers. > > Changes to CSA: > SKIP_WRITE_BARRIER and Store*NoWriteBarrier are verified by the > MemoryOptimizer by default. > Type information about the stored values (TNode<Smi>) is exploited to > safely skip write barriers for stored Smi values. > In some cases, the code is re-structured to make it easier to consume > for the MemoryOptimizer (manual branch and load elimination). > > Changes to the MemoryOptimizer: > Improve the MemoryOptimizer to remove write barriers: > - When the store happens to a CSA-generated InnerAllocate, by ignoring > Bitcasts and additions. > - When the stored value is the HeapConstant of an immortal immovable root. > - When the stored value is a SmiConstant (recognized by BitcastToTaggedSigned). > - Fast C-calls are treated as non-allocating. > - Runtime calls can be white-listed as non-allocating. > > Remaining missing cases: > - C++-style iterator loops with inner pointers. > - Inner allocates that are reloaded from a field where they were just stored > (for example an elements backing store). Load elimination would fix that. > - Safe stored value types that cannot be expressed in CSA (e.g., Smi|Hole). > We could handle that in Torque. > - Double-aligned allocations, which are not lowered in the MemoryOptimizer > but in CSA. > > Drive-by change: Avoid Smi suffix for StoreFixedArrayElement since this > can be handled by overload resolution (in Torque and C++). > > R=​jarin@chromium.org > TBR=mvstanton@chromium.org > > Change-Id: I0af9b710673f350e0fe81c2e59f37da93c024b7c > Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1571414 > Commit-Queue: Tobias Tebbi <tebbi@chromium.org> > Reviewed-by: Jaroslav Sevcik <jarin@chromium.org> > Cr-Commit-Position: refs/heads/master@{#61016} TBR=mvstanton@chromium.org,jarin@chromium.org,tebbi@chromium.org Change-Id: I36877cd6d08761726ef8dce8a3e3f2ce3eebe6cf No-Presubmit: true No-Tree-Checks: true No-Try: true Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1585732 Reviewed-by: Ross McIlroy <rmcilroy@chromium.org> Commit-Queue: Ross McIlroy <rmcilroy@chromium.org> Cr-Commit-Position: refs/heads/master@{#61038}		2019-04-26 10:03:33 +00:00
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binutils	Python3 compatibility: use open() instead of file()	2019-04-05 16:22:20 +00:00
colorama	Add colorama package to DEPS so that pylib can import it	2017-10-24 14:18:49 +00:00
googletest	Update V8 DEPS.	2019-01-22 14:49:04 +00:00
inspector_protocol	[DevTools] Roll inspector_protocol for v8.	2019-04-16 19:49:11 +00:00
v8/builtins	Revert "[csa] verify skipped write-barriers in MemoryOptimizer"	2019-04-26 10:03:33 +00:00
wasm-api	[wasm-c-api] Add upstream examples as tests	2019-04-17 18:04:16 +00:00