Access component-model flags via their VmType alias region in adapters - #14116
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fitzgen merged 2 commits intoAug 20, 2026
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Aug 14, 2026
These flags were imported by adapters and accessed with the `PublicGlobal` alias
region, but this led to ambiguity between loads and stores to different
flags. The flags are stored in the `VMComponentContext` and we generally know
when we are importing flags as globals unambiguously, so do the same thing we do
to get precise alias regions for defined globals for component-model flags, but
use the `AliasRegionKey::Vm { ty: VMComponentContext, .. }` alias region.
A final wrinkle: core Wasm does not have the enclosing `VMComponentContext`'s
offsets on hand, so we move `task_may_block` ahead of `may_leave` so both flags
are before every component-shape-dependent field and the flags' offsets are a
function of the pointer size alone.
Avoid defining new `AliasRegions` helpers and use macro-generated helpers instead.
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@alexcrichton mind taking another look? when rebasing this, it went across the vmctx macro stuff, so I added another commit that makes it avoid defining new |
alexcrichton
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Aug 20, 2026
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These flags were imported by adapters and accessed with the
PublicGlobalaliasregion, but this led to ambiguity between loads and stores to different
flags. The flags are stored in the
VMComponentContextand we generally knowwhen we are importing flags as globals unambiguously, so do the same thing we do
to get precise alias regions for defined globals for component-model flags, but
use the
AliasRegionKey::Vm { ty: VMComponentContext, .. }alias region.A final wrinkle: core Wasm does not have the enclosing
VMComponentContext'soffsets on hand, so we move
task_may_blockahead ofmay_leaveso both flagsare before every component-shape-dependent field and the flags' offsets are a
function of the pointer size alone.
Depends on #14115