llvm / llvm/circt

[firtool] OM MemorySchema prevents round-tripping FIRRTL output

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FIRRTL
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C++
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Description

When running a design through firtool with --repl-seq-mem enabled and --ir-fir to emit FIRRTL dialect IR, the resulting file cannot be run through firtool again to get SV output. The intermediate FIRRTL dialect IR file contains om.class @MemorySchema objects, which get re-created in the second run through firtool, which causes the verifier to detect a duplicate definition of @MemorySchema.

Should the --repl-seq-mem option be sensitive to classes already having been declared, and just update them if present?

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Research direction

Reproduce the two-stage firtool flow using --repl-seq-mem and --ir-fir, then inspect the emitted FIRRTL dialect IR for the om.class @MemorySchema definitions. Trace how the second invocation handles those existing classes; done means the round trip reaches SV output without a duplicate-definition verifier error.

Written by the indexing model from the issue text.

Assessment

Tech stack
cpp
Domain
compilers
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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