Warn on functions that may be too big for some VMs #1246
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Any thoughts on if we should show this warning about big functions? |
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Background: WebAssembly/design#1138 - browser vendors are starting to apply a new limit on function body size, to 128K. This was apparently agreed upon before, but not applied. There is also a movement to a larger constant than 128K, but at least Edge will have the 128K limit for several months (and Chrome just started to apply it on Canary, but might get the new larger constant soon, not clear).
So this PR emits a warning when a function body is 128K or more. The warning might be enough for some users, as they may be able to disable inlining or other optimizations, if they were the cause of the large function. However, it's possible that won't always be an option, either because it's not simple to tweak those optimizations without downsides, or because the big function is the output of a code generator.
This PR also creates a "table of contents" for each function, which may be useful for other things soon.