Compat changes for wasm 2.0.0#267
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I added a commit that now allows returning I64's across the boundary as a multi-value made up of two I32s. This is required to expose Hacl_Bignum64_add for @danwallach |
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| (* See digression for [dup32] in CFlatToWasm *) | ||
| let scratch_locals = | ||
| [ I64; I64; I32; I32 ] |
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the top-of-the-stack pointer is now always saved in the fifth local
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(as opposed to being left on the stack, which used to require contortions to swap operands at the top of the stack)
| WASM." | ||
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| let mk_decl env (d: decl): env * CF.decl option = | ||
| let mk_wrapper orig_name n_args locals = |
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the strategy for returning 64-bit integers to javascript is as follows:
- if the function
fis part of the public API - and returns a uint64
then we generate a _packed variant that callsf, then decomposes the uint64 return value as a pair of uint32s
since krml does not take advantage of multi-value returns (it should! but these weren't supported when I wrote the backend), a special instruction here allows converting a 64-bit integer into two 32-bit integers...
in the future, it'd be good to add general support for multi-values, and then simply call WasmSupport.u64tou32s of type uint64 -> uint32 & uint32
| in | ||
| (if name <> "WasmSupport_align_64" then Debug.mk env debug_enter else []) @ | ||
| read_highwater @ | ||
| [ dummy_phrase (W.Ast.LocalSet (mk_var (env.n_args + 4))) ] @ |
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here, instead of leaving the top-of-the-(memory)-stack pointer on top of the (operand) stack, we save it in the reserved local
denismerigoux
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denismerigoux
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Looks good to me, even though I didn't have a good knowledge of that part of the codebase.
W95Psp
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W95Psp
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Don't know much about Karamel's extraction to WASM, but this seems good to me :)
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To be merged after ocaml/opam-repository#21446 gets merged.