Support global.get in more constant expressions
#7996
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This commit updates Wasmtime to support `global.get` in constant expressions when located in table initializers and element segments. Pre-reference-types this never came up because there was no valid `global.get` that would typecheck. After the reference-types proposal landed however this became possible but Wasmtime did not support it. This was surfaced in bytecodealliance#6705 when the spec test suite was updated and has a new test that exercises this functionality. This commit both updates the spec test suite and additionally adds support for this new form of element segment and table initialization expression. The fact that Wasmtime hasn't supported this until now also means that we have a gap in our fuzz-testing infrastructure. The `wasm-smith` generator is being updated in bytecodealliance/wasm-tools#1426 to generate modules with this particular feature and I've tested that with that PR fuzzing here eventually generates an error before this PR. Closes bytecodealliance#6705
alexcrichton
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Feb 28, 2024
This fixes a mistake introduced in bytecodealliance#7996 where a `global.get` used to initialize a table did not properly drop previous items in the table causing them to leak as the reference count was not decremented.
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This commit updates Wasmtime to support
global.getin constant expressions when located in table initializers and element segments. Pre-reference-types this never came up because there was no validglobal.getthat would typecheck. After the reference-types proposal landed however this became possible but Wasmtime did not support it. This was surfaced in #6705 when the spec test suite was updated and has a new test that exercises this functionality.This commit both updates the spec test suite and additionally adds support for this new form of element segment and table initialization expression.
The fact that Wasmtime hasn't supported this until now also means that we have a gap in our fuzz-testing infrastructure. The
wasm-smithgenerator is being updated in bytecodealliance/wasm-tools#1426 to generate modules with this particular feature and I've tested that with that PR fuzzing here eventually generates an error before this PR.Closes #6705