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41 lines
1.9 KiB
Plaintext
41 lines
1.9 KiB
Plaintext
//===-- README.txt - Notes for WebAssembly code gen -----------------------===//
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This WebAssembly backend is presently in a very early stage of development.
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The code should build and not break anything else, but don't expect a lot more
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at this point.
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For more information on WebAssembly itself, see the design documents:
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* https://github.com/WebAssembly/design/blob/master/README.md
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The following documents contain some information on the planned semantics and
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binary encoding of WebAssembly itself:
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* https://github.com/WebAssembly/design/blob/master/AstSemantics.md
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* https://github.com/WebAssembly/design/blob/master/BinaryEncoding.md
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Interesting work that remains to be done:
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* Write a pass to restructurize irreducible control flow. This needs to be done
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before register allocation to be efficient, because it may duplicate basic
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blocks and WebAssembly performs register allocation at a whole-function
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level. Note that LLVM's GPU code has such a pass, but it linearizes control
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flow (e.g. both sides of branches execute and are masked) which is undesirable
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for WebAssembly.
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//===---------------------------------------------------------------------===//
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set_local and store instructions have a return value. We should (a) model this,
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and (b) write optimizations which take advantage of it. Keep in mind that
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many set_local instructions are implicit!
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//===---------------------------------------------------------------------===//
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Load and store instructions can have a constant offset. We should (a) model
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this, and (b) do address-mode folding with it.
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//===---------------------------------------------------------------------===//
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Br, br_if, and tableswitch instructions can support having a value on the
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expression stack across the jump (sometimes). We should (a) model this, and
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(b) extend the stackifier to utilize it.
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//===---------------------------------------------------------------------===//
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