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Glow-Lang
Systematic support for call-by-value vs call-by-reference in EVM backend
In GitLab by @fahree on Dec 15, 2020, 01:25
Description
We would like to support boxed types in addition the current support for unboxed types.
Example builtin non-immediate types:
-
Signature(65 bytes, r, s, v fields)
And then at some point we need to handle strings: immediate, non-immediate? A new kind of "indirect" values?
- a
ByteStringhas a length + an offset in memory.
What we need
- Notion of immediate vs non-immediate types.
- Provide the proper interface for marshaling values to the EVM. Type descriptors with methods for storing / loading etc...
Patches for gerbil-ethereum
Tracked here.
Patches for Glow
Type descriptors (See: https://gitlab.com/mukn/glow/-/merge_requests/158)
- [ ] boxed/unboxed type descriptor
- [ ] size descriptors
- [ ] descriptors for conversion between objects, bytes.
Refactor current handling
Consensus code generator handles variables in the following way:
- Get type via
lookup-type:(def type (lookup-type (.@ self program) argument-name)) - Get length via
param-length:(def len (and type (param-length type))) - Get static offset via
lookup-variable-offset. - Use
mloadat/mstoreatto handle the variable's loading / storing.
Once EVM type descriptor interface is stabilized, we should use its methods instead. In consensus code generator:
- [ ] Update
define-small-functionsto use EVM type descriptor methods. - [ ] Update
compile-consensus-statementto use EVM type descriptor methods. - [ ] Update
load-immediate-variableto use EVM type descriptor methods. - [ ] Update
add-local-variable-to-frameto use EVM type descriptor methods. - [ ] Update
add-temporary-variable-offsetto use EVM type descriptor methods. - [ ] Update
trivial-expressionto use EVM type descriptor methods. - [ ] Update
setup-tail-callto use EVM type descriptor methods. - [ ] Update
compute-variable-offsetsto use EVM type descriptor methods.
TODO how to integrate with EVM type descriptor methods? TODO any other areas we need to handle?
In GitLab by @fahree on Dec 15, 2020, 01:44
- [ ] In Ethereum types, have a notion of immediate vs non-immediate type
- [ ] Immediate types are stored directly on the stack, e.g. integers less than 256 bits, objects that fit in 256 bits in general
- [ ] Non-immediate objects are stored in memory, and only their 16- or 24-bit offset in passed on the EVM stack.
- [ ] We want type descriptors, etc., to convert between objects and bytes, to generate the proper EVM code, etc.
Example builtin non-immediate types:
-
Signature(65 bytes, r, s, v fields)
And then at some point we need to handle strings: immediate, non-immediate? A new kind of "indirect" values?
- a
ByteStringhas a length + an offset in memory.
Methods?
- [ ] Hashing
- [ ] get to stack, store from stack, copy, etc., on the EVM backend.
In GitLab by @fahree on Dec 15, 2020, 03:50
assigned to @AlexKnauth and @Akaa
In GitLab by @kwanzknoel on May 11, 2021, 01:33
marked this issue as related to #68
In GitLab by @kwanzknoel on May 11, 2021, 01:33
marked this issue as related to #115
In GitLab by @kwanzknoel on May 11, 2021, 01:47
Note: as mentioned by @fahree, until we have user-defined data structures, the only data structure in need of references is Signature.
In GitLab by @kwanzknoel on May 11, 2021, 16:34
Type descriptors are similar to typeclasses in Haskell.
In GitLab by @kwanzknoel on May 11, 2021, 20:47
EVM backends and other similar backends define a predicate: immediate?. This enables us to discriminate between immediate and non-immediate entities, i.e. whether an entity can be represented in a way that fits into a single stack entry / register (depending on VM).
We will choose an indirect type representation for those which cannot fit.
In GitLab by @kwanzknoel on May 11, 2021, 20:48
Task prerequisites: understanding of EVM, glow type descriptors, glow consensus code gen.
In GitLab by @kwanzknoel on Jun 2, 2021, 03:55
marked this issue as related to #191
In GitLab by @kwanzknoel on Jun 2, 2021, 21:17
marked the task boxed? method to discriminate between the two. as completed
In GitLab by @kwanzknoel on Jun 25, 2021, 01:51
marked the task boxed? method to discriminate between the two. as incomplete