Enum Trampoline

Source

pub enum Trampoline {
Show 38 variants    LowerImport {
        index: LoweredIndex,
        lower_ty: TypeFuncIndex,
        options: CanonicalOptions,
    },
    Transcoder {
        op: Transcode,
        from: RuntimeMemoryIndex,
        from64: bool,
        to: RuntimeMemoryIndex,
        to64: bool,
    },
    AlwaysTrap,
    ResourceNew(TypeResourceTableIndex),
    ResourceRep(TypeResourceTableIndex),
    ResourceDrop(TypeResourceTableIndex),
    TaskBackpressure {
        instance: RuntimeComponentInstanceIndex,
    },
    TaskReturn,
    TaskWait {
        instance: RuntimeComponentInstanceIndex,
        async_: bool,
        memory: RuntimeMemoryIndex,
    },
    TaskPoll {
        instance: RuntimeComponentInstanceIndex,
        async_: bool,
        memory: RuntimeMemoryIndex,
    },
    TaskYield {
        async_: bool,
    },
    SubtaskDrop {
        instance: RuntimeComponentInstanceIndex,
    },
    StreamNew {
        ty: TypeStreamTableIndex,
    },
    StreamRead {
        ty: TypeStreamTableIndex,
        options: CanonicalOptions,
    },
    StreamWrite {
        ty: TypeStreamTableIndex,
        options: CanonicalOptions,
    },
    StreamCancelRead {
        ty: TypeStreamTableIndex,
        async_: bool,
    },
    StreamCancelWrite {
        ty: TypeStreamTableIndex,
        async_: bool,
    },
    StreamCloseReadable {
        ty: TypeStreamTableIndex,
    },
    StreamCloseWritable {
        ty: TypeStreamTableIndex,
    },
    FutureNew {
        ty: TypeFutureTableIndex,
    },
    FutureRead {
        ty: TypeFutureTableIndex,
        options: CanonicalOptions,
    },
    FutureWrite {
        ty: TypeFutureTableIndex,
        options: CanonicalOptions,
    },
    FutureCancelRead {
        ty: TypeFutureTableIndex,
        async_: bool,
    },
    FutureCancelWrite {
        ty: TypeFutureTableIndex,
        async_: bool,
    },
    FutureCloseReadable {
        ty: TypeFutureTableIndex,
    },
    FutureCloseWritable {
        ty: TypeFutureTableIndex,
    },
    ErrorContextNew {
        ty: TypeComponentLocalErrorContextTableIndex,
        options: CanonicalOptions,
    },
    ErrorContextDebugMessage {
        ty: TypeComponentLocalErrorContextTableIndex,
        options: CanonicalOptions,
    },
    ErrorContextDrop {
        ty: TypeComponentLocalErrorContextTableIndex,
    },
    ResourceTransferOwn,
    ResourceTransferBorrow,
    ResourceEnterCall,
    ResourceExitCall,
    AsyncEnterCall,
    AsyncExitCall {
        callback: Option<RuntimeCallbackIndex>,
        post_return: Option<RuntimePostReturnIndex>,
    },
    FutureTransfer,
    StreamTransfer,
    ErrorContextTransfer,
}

Expand description

A list of all possible trampolines that may be required to compile a component completely.

These trampolines are used often as core wasm definitions and require Cranelift support to generate these functions. Each trampoline serves a different purpose for implementing bits and pieces of the component model.

All trampolines have a core wasm function signature associated with them which is stored in the Component::trampolines array.

Note that this type does not implement Serialize or Deserialize and that’s intentional as this isn’t stored in the final compilation artifact.

Variants§

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LowerImport

Description of a lowered import used in conjunction with GlobalInitializer::LowerImport.

Fields

§index: LoweredIndex

The runtime lowering state that this trampoline will access.

§lower_ty: TypeFuncIndex

The type of the function that is being lowered, as perceived by the component doing the lowering.

§options: CanonicalOptions

The canonical ABI options used when lowering this function specified in the original component.

§

Transcoder

Information about a string transcoding function required by an adapter module.

A transcoder is used when strings are passed between adapter modules, optionally changing string encodings at the same time. The transcoder is implemented in a few different layers:

Each generated adapter module has some glue around invoking the transcoder represented by this item. This involves bounds-checks and handling realloc for example.
Each transcoder gets a cranelift-generated trampoline which has the appropriate signature for the adapter module in question. Existence of this initializer indicates that this should be compiled by Cranelift.
The cranelift-generated trampoline will invoke a “transcoder libcall” which is implemented natively in Rust that has a signature independent of memory64 configuration options for example.

Fields

§op: Transcode

The transcoding operation being performed.

§from: RuntimeMemoryIndex

The linear memory that the string is being read from.

§from64: bool

Whether or not the source linear memory is 64-bit or not.

§to: RuntimeMemoryIndex

The linear memory that the string is being written to.

§to64: bool

Whether or not the destination linear memory is 64-bit or not.

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AlwaysTrap

A small adapter which simply traps, used for degenerate lift/lower combinations.

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ResourceNew(TypeResourceTableIndex)

A resource.new intrinsic which will inject a new resource into the table specified.

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ResourceRep(TypeResourceTableIndex)

Same as ResourceNew, but for the resource.rep intrinsic.

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ResourceDrop(TypeResourceTableIndex)

Same as ResourceNew, but for the resource.drop intrinsic.

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TaskBackpressure

A task.backpressure intrinsic, which tells the host to enable or disable backpressure for the caller’s instance.

Fields

§instance: RuntimeComponentInstanceIndex

The specific component instance which is calling the intrinsic.

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TaskReturn

A task.return intrinsic, which returns a result to the caller of a lifted export function. This allows the callee to continue executing after returning a result.

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TaskWait

A task.wait intrinsic, which waits for at least one outstanding async task/stream/future to make progress, returning the first such event.

Fields

§instance: RuntimeComponentInstanceIndex

The specific component instance which is calling the intrinsic.

§async_: bool

If true, indicates the caller instance maybe reentered.

§memory: RuntimeMemoryIndex

Memory to use when storing the event.

§

TaskPoll

A task.poll intrinsic, which checks whether any outstanding async task/stream/future has made progress. Unlike task.wait, this does not block and may return nothing if no such event has occurred.

Fields

§instance: RuntimeComponentInstanceIndex

The specific component instance which is calling the intrinsic.

§async_: bool

If true, indicates the caller instance maybe reentered.

§memory: RuntimeMemoryIndex

Memory to use when storing the event.

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TaskYield

A task.yield intrinsic, which yields control to the host so that other tasks are able to make progress, if any.

Fields

§async_: bool

If true, indicates the caller instance maybe reentered.

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SubtaskDrop

A subtask.drop intrinsic to drop a specified task which has completed.

Fields

§instance: RuntimeComponentInstanceIndex

The specific component instance which is calling the intrinsic.

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StreamNew

A stream.new intrinsic to create a new stream handle of the specified type.

Fields

§ty: TypeStreamTableIndex

The table index for the specific stream type and caller instance.

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StreamRead

A stream.read intrinsic to read from a stream of the specified type.

Fields

§ty: TypeStreamTableIndex

The table index for the specific stream type and caller instance.

§options: CanonicalOptions

Any options (e.g. string encoding) to use when storing values to memory.

§

StreamWrite

A stream.write intrinsic to write to a stream of the specified type.

Fields

§ty: TypeStreamTableIndex

The table index for the specific stream type and caller instance.

§options: CanonicalOptions

Any options (e.g. string encoding) to use when storing values to memory.

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StreamCancelRead

A stream.cancel-read intrinsic to cancel an in-progress read from a stream of the specified type.

Fields

§ty: TypeStreamTableIndex

The table index for the specific stream type and caller instance.

§async_: bool

If false, block until cancellation completes rather than return BLOCKED.

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StreamCancelWrite

A stream.cancel-write intrinsic to cancel an in-progress write from a stream of the specified type.

Fields

§ty: TypeStreamTableIndex

The table index for the specific stream type and caller instance.

§async_: bool

If false, block until cancellation completes rather than return BLOCKED.

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StreamCloseReadable

A stream.close-readable intrinsic to close the readable end of a stream of the specified type.

Fields

§ty: TypeStreamTableIndex

The table index for the specific stream type and caller instance.

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StreamCloseWritable

A stream.close-writable intrinsic to close the writable end of a stream of the specified type.

Fields

§ty: TypeStreamTableIndex

The table index for the specific stream type and caller instance.

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FutureNew

A future.new intrinsic to create a new future handle of the specified type.

Fields

§ty: TypeFutureTableIndex

The table index for the specific future type and caller instance.

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FutureRead

A future.read intrinsic to read from a future of the specified type.

Fields

§ty: TypeFutureTableIndex

The table index for the specific future type and caller instance.

§options: CanonicalOptions

Any options (e.g. string encoding) to use when storing values to memory.

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FutureWrite

A future.write intrinsic to write to a future of the specified type.

Fields

§ty: TypeFutureTableIndex

The table index for the specific future type and caller instance.

§options: CanonicalOptions

Any options (e.g. string encoding) to use when storing values to memory.

§

FutureCancelRead

A future.cancel-read intrinsic to cancel an in-progress read from a future of the specified type.

Fields

§ty: TypeFutureTableIndex

The table index for the specific future type and caller instance.

§async_: bool

If false, block until cancellation completes rather than return BLOCKED.

§

FutureCancelWrite

A future.cancel-write intrinsic to cancel an in-progress write from a future of the specified type.

Fields

§ty: TypeFutureTableIndex

The table index for the specific future type and caller instance.

§async_: bool

If false, block until cancellation completes rather than return BLOCKED.

§

FutureCloseReadable

A future.close-readable intrinsic to close the readable end of a future of the specified type.

Fields

§ty: TypeFutureTableIndex

The table index for the specific future type and caller instance.

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FutureCloseWritable

A future.close-writable intrinsic to close the writable end of a future of the specified type.

Fields

§ty: TypeFutureTableIndex

The table index for the specific future type and caller instance.

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ErrorContextNew

A error-context.new intrinsic to create a new error-context with a specified debug message.

Fields

§ty: TypeComponentLocalErrorContextTableIndex

The table index for the error-context type in the caller instance.

§options: CanonicalOptions

String encoding, memory, etc. to use when loading debug message.

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ErrorContextDebugMessage

A error-context.debug-message intrinsic to get the debug message for a specified error-context.

Note that the debug message might not necessarily match what was passed to error.new.

Fields

§ty: TypeComponentLocalErrorContextTableIndex

The table index for the error-context type in the caller instance.

§options: CanonicalOptions

String encoding, memory, etc. to use when storing debug message.

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ErrorContextDrop

A error-context.drop intrinsic to drop a specified error-context.

Fields

§ty: TypeComponentLocalErrorContextTableIndex

The table index for the error-context type in the caller instance.

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ResourceTransferOwn

An intrinsic used by FACT-generated modules which will transfer an owned resource from one table to another. Used in component-to-component adapter trampolines.

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ResourceTransferBorrow

Same as ResourceTransferOwn but for borrows.

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ResourceEnterCall

An intrinsic used by FACT-generated modules which indicates that a call is being entered and resource-related metadata needs to be configured.

Note that this is currently only invoked when borrowed resources are detected, otherwise this is “optimized out”.

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ResourceExitCall

Same as ResourceEnterCall except for when exiting a call.

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AsyncEnterCall

An intrinsic used by FACT-generated modules to begin a call to an async-lowered import function.

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AsyncExitCall

An intrinsic used by FACT-generated modules to complete a call to an async-lowered import function.

Note that AsyncEnterCall and AsyncExitCall could theoretically be combined into a single AsyncCall intrinsic, but we separate them to allow the FACT-generated module to optionally call the callee directly without an intermediate host stack frame.

Fields

§callback: Option<RuntimeCallbackIndex>

The callee’s callback, if any.

§post_return: Option<RuntimePostReturnIndex>

The callee’s post-return function, if any.

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FutureTransfer

An intrinisic used by FACT-generated modules to (partially or entirely) transfer ownership of a future.

Transfering a future can either mean giving away the readable end while retaining the writable end or only the former, depending on the ownership status of the future.

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StreamTransfer

An intrinisic used by FACT-generated modules to (partially or entirely) transfer ownership of a stream.

Transfering a stream can either mean giving away the readable end while retaining the writable end or only the former, depending on the ownership status of the stream.

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ErrorContextTransfer

An intrinisic used by FACT-generated modules to (partially or entirely) transfer ownership of an error-context.

Unlike futures, streams, and resource handles, error-context handles are reference counted, meaning that sharing the handle with another component does not invalidate the handle in the original component.