[LLHD] Add new RefType to replace hw::InOutType #9081
Merged
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Scheremo
approved these changes
Oct 10, 2025
Contributor
Scheremo
left a comment
Scheremo
left a comment
There was a problem hiding this comment.
Mostly LGTM. Quite a bit of churn, but very sensible changes imo!
Lots of doc comment in LLHD Op table gen files still refer to operators returning hw.inout types. Would be nice to update 😃
Comment on lines
1826
to
+1828
| typeConverter.addConversion([&](RefType type) -> std::optional<Type> { | ||
| if (auto innerType = typeConverter.convertType(type.getNestedType())) { | ||
| if (hw::isHWValueType(innerType)) | ||
| return hw::InOutType::get(innerType); | ||
| // TODO: There is some abstraction missing here to correctly return a | ||
| // reference of a CHandle; return an error for now. | ||
| if (isa<mlir::LLVM::LLVMPointerType>(innerType)) { | ||
| mlir::emitError(mlir::UnknownLoc::get(type.getContext())) | ||
| << "Emission of references of LLVMPointerType is currently " | ||
| "unsupported!"; | ||
| return {}; | ||
| } | ||
| } | ||
| if (auto innerType = typeConverter.convertType(type.getNestedType())) | ||
| return llhd::RefType::get(innerType); |
Comment on lines
+485
to
+497
| // CHECK: [[TMP:%.+]] = llvm.mlir.zero : !llvm.ptr | ||
| // CHECK: llhd.sig [[TMP]] : !llvm.ptr | ||
| moore.variable : <!moore.chandle> | ||
|
|
||
| // CHECK: [[TMP:%.+]] = llhd.constant_time <0 | ||
| // CHECK: llhd.sig [[TMP]] : !llhd.time | ||
| moore.variable : <!moore.time> | ||
|
|
||
| // CHECK: [[TMP:%.+]] = llhd.constant_time | ||
| // CHECK: llhd.sig [[TMP]] : !llhd.time | ||
| %c42_fs = moore.constant_time 42 fs | ||
| moore.variable %c42_fs : <!moore.time> | ||
|
|
Add a `RefType` to the LLHD dialect and replace all uses of HW's `InOutType` across the LLHD dialect and the ImportVerilog pipeline. We have been abusing the inout type to mean "signal/variable reference", which becomes problematic if we are trying to place `!llhd.time` or `!llvm.ptr` values behind such a reference. (The HW inout type requires the inner type to be a plain hardware value.) This change now allows the circt-verilog frontend to generate variables with the `time` type and treat them just like any other type. Most of the changes here are just systematic name replacements. I have also removed a few `qualified(...)` wrappers around types and made sure that when an op is known to accept or return a ref type, the printer would just print `<T>` instead of `!llhd.ref<T>`. This is the default behavior for unambiguous types, but sometimes this gets lost when explicitly askign for qualified types, or using `functional-type`.
fabianschuiki
force-pushed
the
fschuiki/llhd-ref
branch
from
3a8f9e3 to
fdd7691
Compare
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Add a
RefTypeto the LLHD dialect and replace all uses of HW'sInOutTypeacross the LLHD dialect and the ImportVerilog pipeline. We have been abusing the inout type to mean "signal/variable reference", which becomes problematic if we are trying to place!llhd.timeor!llvm.ptrvalues behind such a reference. (The HW inout type requires the inner type to be a plain hardware value.)This change now allows the circt-verilog frontend to generate variables with the
timetype and treat them just like any other type.Most of the changes here are just systematic name replacements. I have also removed a few
qualified(...)wrappers around types and made sure that when an op is known to accept or return a ref type, the printer would just print<T>instead of!llhd.ref<T>. This is the default behavior for unambiguous types, but sometimes this gets lost when explicitly askign for qualified types, or usingfunctional-type.