Bytecode descriptor's `isMapped` should enforce generated instructions are annotated

[nrainhart]

Bytecodes declared in StackToRegisterMappingCogit#genMappedInlinePrimitive: can specify metadata that will be part of the bytecode descriptor. In particular, isMapped is used to indicate that the bytecode may end up calling a message send, and thus requires to keep a mapping between the bytecode program counter and the machine code one.

However, that metadata is not enough for everything to work: the generated abstract instructions also need to be annotated using Cogit#annotateBytecode:, or else things will fail unpredictably.

These two mechanisms currently need to be kept in sync manually, which makes it easy for bugs to creep in (e.g. see https://github.com/nrainhart/opensmalltalk-vm/commit/5a83ea16b7b612012dd5cbb58e7591f5397c4abc).

We should make this less error-prone, by either adding a validation or enforcing that all bytecodes annotated with isMapped automatically annotate the abstract instructions they generate with Cogit#annotateBytecode:.

cc @guillep in case you want to correct my comments or add something else.

[guillep]

Thanks for the issue :)

El 30 jun 2022, a las 16:07, nrainhart @.***> escribió:

Bytecodes declared in StackToRegisterMappingCogit#genMappedInlinePrimitive: can specify metadata that will be part of the bytecode descriptor. In particular, isMapped is used to indicate that the bytecode may end up calling a message send, and thus requires to keep a mapping between the bytecode program counter and the machine code one.

However, that metadata is not enough for everything to work: the generated abstract instructions also need to be annotated using Cogit#annotateBytecode:, or else things will fail unpredictably.

These two mechanisms currently need to be kept in sync manually, which makes it easy for bugs to creep in (e.g. see @.*** https://github.com/nrainhart/opensmalltalk-vm/commit/5a83ea16b7b612012dd5cbb58e7591f5397c4abc).

We should make this less error-prone, by either adding a validation or enforcing that all bytecodes annotated with isMapped automatically annotate the abstract instructions they generate with Cogit#annotateBytecode:.

cc @guillep https://github.com/guillep in case you want to correct my comments or add something else.

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