Currently we mostly use `toThrow()`, which seems intended for things that throw non-Errors (something that we "forbid" with ESLint).
Hence `toThrowError()` seems more appropriate, and it also simplifies things slightly; see https://jasmine.github.io/api/edge/matchers.html#toThrowError
The Type-4 PostScript -> Wasm compiler emitted i32.const immediates with the
unsigned LEB128 encoder (_emitULEB128). Wasm decodes i32.const as a *signed*
LEB128, so any immediate whose final 7-bit group has bit 0x40 set is
mis-decoded (e.g. 64 -> single byte 0x40 -> read back as -64).
The output-store address for the i-th result is emitted as i32.const (i*8).
For a function with >= 9 outputs the 9th offset is 64, which decodes as -64, so
f64.store targets 0xFFFFFFC0 and traps (memory access out of bounds). The module
still validates and instantiates, so the JS fallback in function.js is not
engaged; the trap only surfaces at render time (the affected shading / tint
transform silently fails to render). The same mis-encoding affects the constant
bitshift amount.
Add a signed-LEB128 emitter (_emitSLEB128) and use it for the three i32.const
immediate sites; local/import/type indices remain unsigned (correct). Add a unit
test covering functions with 9+ outputs, and a reference test rendering a shading
whose colour function has 9 outputs.
The main goal is to remove the eval-based interpreter.
In order to have some good performances, the new parser performs some optimizations
on the AST (similar to the ones in the previous implementation),
and the Wasm compiler generates code for the optimized AST.
For now, in case of errors or unsupported features, the Wasm compiler returns null
and the old interpreter is used as a fallback.
Few things are still missing:
- a wasm-based interpreter using a stack (in case the ps code isn't stack-free);
- a better js implementation in case of disabled wasm.
but they will be added in follow-up patches.
