wazero

Files

Crypt Keeper 761347db1e Replaces MemorySizer and CompileConfig with RuntimeConfig (#815 )

We formerly introduced `MemorySizer` as a way to control capacity independently of size. This was the first and only feature in `CompileConfig`. While possibly used privately, `MemorySizer` has never been used in public GitHub code.

These APIs interfere with how we do caching of compiled modules. Notably, they can change the min or max defined in wasm, which invalidates some constants. This has also had a bad experience, forcing everyone to boilerplate`wazero.NewCompileConfig()` despite that API never being used in open source.

This addresses the use cases in a different way, by moving configuration to `RuntimeConfig` instead. This allows us to remove `MemorySizer` and `CompileConfig`, and the problems with them, yet still retaining functionality in case someone uses it.

* `RuntimeConfig.WithMemoryLimitPages(uint32)`: Prevents memory from growing to 4GB (spec limit) per instance.
  * This works regardless of whether the wasm encodes max or not. If there is no max, it becomes effectively this value.
* `RuntimeConfig.WithMemoryCapacityFromMax(bool)`: Prevents reallocations (when growing).
  * Wasm that never sets max will grow from min to the limit above.

Note: Those who want to change their wasm (ex insert a max where there was none), have to do that externally, ex via compiler settings or post-build transformations such as [wabin](https://github.com/tetratelabs/wabin)

Signed-off-by: Adrian Cole <adrian@tetrate.io>

2022-09-29 08:03:03 +08:00

testdata

Updates all 3rd party dependencies (#802 )

2022-09-07 11:02:26 +08:00

greet_test.go

Adds Zig example (#741 )

2022-08-11 16:31:06 +08:00

greet.go

Replaces MemorySizer and CompileConfig with RuntimeConfig (#815 )

2022-09-29 08:03:03 +08:00

README.md

Updates all 3rd party dependencies (#802 )

2022-09-07 11:02:26 +08:00

README.md

Zig allocation example

This example shows how to pass strings in and out of a Wasm function defined in Zig, built with zig build.

Ex.

$ go run greet.go wazero
wasm >> Hello, wazero!
go >> Hello, wazero!

greet.zig does a few things of interest:

Uses @ptrToInt to change a Zig pointer to a numeric type
Uses [*]u8 as an argument to take a pointer and slices it to build back a string

The Zig code exports "malloc" and "free", which we use for that purpose.

Notes

This example uses @panic() rather than unreachable to handle errors since unreachable emits a call to panic only in Debug and ReleaseSafe mode. In ReleaseFast and ReleaseSmall mode, it would lead into undefined behavior.

If building wasm with a pre-release version of Zig 0.10.0, use -fstage1 to avoid bugs in the new compiler.