Add opcodes for dynamically indexing into Txn array fields#2847
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## master #2847 +/- ##
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Coverage 47.25% 47.26%
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Files 351 351
Lines 56363 56481 +118
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+ Hits 26634 26694 +60
- Misses 26735 26772 +37
- Partials 2994 3015 +21
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We need to think about whether we should add some pseudo op support. Currently, txn ApplicationArgs 0 gets compiled to txna ApplicationArgs 0, because of the two arguments signaling that it's an array ref. txnsa can also be compiled from txns (I think).
I'm not sure we can do much here, but it is a little strange that once you move to the stack versions, the "a" becomes required.
Let me talk through a strawman proposal and see if it makes sense:
txns could be introduced as a substitute for txnas
gtxns could compile to gtxnas if it is using an Array field? (this would be a departure, we normally go by the number of immediates, but the whole point of these new opcodes is that they access an array but do NOT, have an extra immediate)
gtxnss could compile to gtxnsas
I'm really unsure this makes sense. I'm just trying to fit in with our existing choices to not require the "a" in the the txn opcodes during assembly.
… algochoi/dynamic-index-array
| if gtxid >= len(cx.TxnGroup) { | ||
| cx.err = fmt.Errorf("gtxnas lookup TxnGroup[%d] but it only has %d", gtxid, len(cx.TxnGroup)) | ||
| return | ||
| } else if gtxid < 0 { | ||
| cx.err = fmt.Errorf("gtxnas lookup %d cannot be negative", gtxid) | ||
| return | ||
| } |
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I'll fix this up when I do loads, stores, but just want to point out that we don't want to complain that the number is negative. In AVM, it isn't. It's only negative (potentially) because this code casted a big uint64 to an int, and that can give you a negative result.
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PS, I liked the way you handled this in args a lot. There, you used uint64 mostly, and casted the len() calls instead of the stack argument. I think I will fix this stuff up that way, instead of the way I had been contemplating.
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| func assembleGtxnsas(ops *OpStream, spec *OpSpec, args []string) error { | ||
| if len(args) != 1 { | ||
| return ops.error("gtxnsas expects one immediate argument") |
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Let's try to use %s and spec.Name as often as possible.
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Agreed - I think we can potentially save ourselves time in the future by doing this.
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| ` | ||
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| gtxnTextV5 := gtxnTextV4 + `int 0 |
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I put txnas in the testTxnProgramTextV5 section I think.
| txgroup[0] = txn | ||
| ep := defaultEvalParams(nil, &txn) | ||
| ep.TxnGroup = txgroup | ||
| _, err := Eval(ops.Program, ep) |
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I think you're just checking that the programs runs, not that it passes? It would be a stronger test to instead check that a simple use of txnas passes. I'd suggest something like the following, and you could adapt it for gtxnas and gtxnsas too.
int 0
txnas Accounts
txna Accounts 0
==
int 0
txnas ApplicationArgs
txna ApplicationArgs 0
==
&&
int 1
txnas ApplicationArgs
txna ApplicationArgs 1
==
&&
return
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Good point, I will check these with e.g. testAccepts(t, "int 0; txnas Accounts; txna Accounts 0; ==", 5)
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I merged what existed, I'll add these.
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I concluded these were fine. The following tests checked pass, and they were grabbing the accounts and comparing them to app args.
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Summary
This commit adds
txnas,gtxnas, andgtxnsasop codes that allow for array indices to be dynamically pushed into the stack instead of being supplied by immediate values. It also adds theargsop code to dynamically specify an arg index from the stack.TODO: Implement
stores,loadsCloses #2799
Test Plan