Pretty Print Failing Line/Column

[seldridge]

tl;dr: Print out GCC/LLVM-style to pretty-print error information with the failing line and a carat to the failing column.

Checklist

• [x] Did you write out a description of the feature you want to see?
• [x] Did you look around for any related features?
• [x] Did you specify relevant external information?

Feature Description

Consider the following circuit that will error during elaboration:

class Foo extends MultiIOModule {
  val in = IO(Input(UInt(1.W)))
  val out = IO(Output(SInt(1.W))) 
  out := in
}

Currently connecting an SInt and UInt errors with the correct, but possibly confusing:

[info] [0.005] Elaborating design...
[error] chisel3.internal.ChiselException: Connection between sink (SInt<1>(IO in unelaborated Foo)) and source (UInt<1>(IO in unelaborated Foo)) failed @: Sink (SInt<1>(IO in unelaborated Foo)) and Source (UInt<1>(IO in unelaborated Foo)) have different types.
[error]     ...
[error]     at Playground$Foo.<init>(main.scala:10)
[error]     at Playground$.$anonfun$new$1(main.scala:13)
[error]     ... (Stack trace trimmed to user code only, rerun with --full-stacktrace if you wish to see the full stack trace)

While this is useful, it's still a hunt ot figure out what's going on. It would be way better to pretty print out some GCC/LLVM-style error reporting. Something like:

[error] Connection between sink (SInt<1>(IO in unelaborated Foo)) and source (UInt<1>(IO in unelaborated Foo)) failed @: Sink (SInt<1>(IO in unelaborated Foo)) and Source (UInt<1>(IO in unelaborated Foo)) have different types.
[error] In file Foo.scala:
[error]   out := in
[error]   ~~~~^

This should be pretty trivial to do in FIRRTL once source locators are available, but I'm not sure of the implementation to do this during elaboration in Chisel.

Type of Feature

• documentation
• new feature/API

Related Features

No.

External Information

Equivalent FIRRTL PR: https://github.com/freechipsproject/firrtl/issues/1598

For a motivating example of what this could look like, GCC 10 has some static analysis stuff that looks very pretty: https://developers.redhat.com/blog/2020/03/26/static-analysis-in-gcc-10/

[azidar]

Other areas to pretty-print: type mismatched of fields in bundles. Could report the scala file as well.

[jackkoenig]

This is done in https://github.com/chipsalliance/chisel/pull/3039.