Ever since introducing the Listener, the firrtl Parser now can hit
errors in the code converting from concrete syntax to abstract syntax
that may be due to syntax errors. These errors are essentially broken
assumptions about the structure of the parsed code because there is an
error. These errors are reported before the standard ANTLR syntax errors
are aggregated and reported, and thus could result in less than elegant
error messages (eg. NullPointerException). Now, the Parser will mask off
such errors in the event of standard syntax errors caught by the
ANTLR-generated parser.

This commit also cleans up some ParserSpec tests slightly to make the
ScalaTest style more canonical.

* Parse version and hardcode emitted version

* Throw error if version is too high

* Parse version even if rest is invalid

* Change pattern match to if statement

* Improve version grammar

* Update tests

* Remove outdated comment

* Simplify grammar and use version class

* Simplify and add no version test

* Fix for conflicting lexer rule

The simple functionality is needed in chiseltest.

* Fix Yosys link
* Update SBT version

Fixes #2516

Previously,

reg r : UInt<8>, clock with :
  reset => (p, UInt<8>(3))
r is invalid

would compile to:

reg r : UInt<8>, clock
r <= UInt<8>(0)

now it compiles to:

reg r : UInt<8>, clock
wire r_1 : UInt<8>
r_1 is invalid
r <= mux(reset, UInt<8>(3), r_1)

This is consistent with the behavior for a reset with an asynchronous
reset.

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Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

Problem: MemConf serialization of MemPorts was not deterministic
and the ordering seems to have changed as we move projects to 2.13
Downstream project can be adversely affected by changes in ordering
This changes specifies as specific ordering that should be compatible with
the historical one.

It is unclear if having more than one circuit annotation even works. If
it does, it is implausible that they would have the same circuit name
since that would correspond to a namespace collision.

Update `findTypeHints` to allow for the "class" field in JSON objects to
appear anywhere in the object. This used to rely on the field being the
very first in the object, which is easily violated when reading JSON
data generated externally, since an object's order of fields is
unspecified and can be arbitrarily scrambled.

Fixes #2497.

Before it would just download another copy of the PDF every time I wanted to go visit the spec repo.

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Signed-off-by: Schuyler Eldridge <schuyler.eldridge@sifive.com>

This removes the FIRRTL specification as this now lives in its own
repository:

    https://github.com/chipsalliance/firrtl-spec



All git history (excluding binary updates to spec.pdf) have been
migrated to the new repository.

Signed-off-by: Schuyler Eldridge <schuyler.eldridge@sifive.com>

This fixes handling of signed modulus and removes some redundant work.

- Convert FIRRTL spec to Markdown file.
- Add PDF generation via pandoc.
- Remove old LaTeX specification.

Co-authored-by: Schuyler Eldridge <schuyler.eldridge@sifive.com>
Signed-off-by: Schuyler Eldridge <schuyler.eldridge@sifive.com>

- Fix & test MemorySynthInit behavior with MemoryArrayInitAnnotation and MemoryScalarInitAnnotation.
Add test case for MemoryRandomInitAnnotation which is, on the contrary, expected not to leak any randomization statement in synthesis context.

- Refactor MemoryInitSpec for improved results readability

Context:

PR #2166 (commit: 4530152) introduced MemorySynthInit annotation to control whether statement generated with Memory*InitAnnotation (emitted within initial begin block in verilog) should be guarded with ifndef SYNTHESIS or not.
Unfortunately only one configuration (MemoryFileInlineAnnotation) has been tested while the others have been generating incorrect verilog statements (MemoryArrayInitAnnotation and MemoryScalarInitAnnotation).

Signed-off-by: Jean Bruant <jean.bruant@ovhcloud.com>

emission-options flags swapped to match their functionality

Verification statements are guarded by reset.
If this reset happens to be a "preset" type
reset, they should always be active.
The easiest way to achieve that is to replace
all uses of "preset" resets with zero.

This fixes an off by one error, where 3 was erroneously
accepted as in-bounds for a memory of depth=3

* Enable CI for 1.5.x branch
* Enable Mergify for 1.5.x branch
* Drop 1.2.x from Mergify

* Add FileInfo to asyncResetAlwaysBlocks

Always blocks need three FileInfo (if, true, false) to show line numbers,
but initially, every always blocks only have one FileInfo (false).

RemoveReset adds the extra two FileInfo to sync always blocks,
so sync always blocks can have line numbers.

Async always blocks don't provide their only FileInfo, so there are no line numbers.

This commit gives async always block the extra FileInfo to show line numbers for them.

This code:

```scala
import chisel3._
import chisel3.stage._
import firrtl.CustomDefaultRegisterEmission

class Test extends Module with RequireAsyncReset {
  val io = IO(new Bundle {
    val in = Input(Bool())
    val out = Output(Bool())
  })
  val valid = RegInit(false.B)
  valid := io.in
  io.out := valid
}

object Test extends App {
  new ChiselStage().execute(Array(), Seq(
    ChiselGeneratorAnnotation(() => new Test()),
    CustomDefaultRegisterEmission(useInitAsPreset = false, disableRandomization = true)
  ))
}
```

will generate this Verilog:

```verilog
module Test(
  input   clock,
  input   reset,
  input   io_in,
  output  io_out
);
  reg  valid; // @[Playground.scala 10:22]
  assign io_out = valid; // @[Playground.scala 12:10]
  always @(posedge clock or posedge reset) begin
    if (reset) begin // @[Playground.scala 10:22]
      valid <= 1'h0; // @[Playground.scala 10:22]
    end else begin
      valid <= io_in; // @[Playground.scala 11:9]
    end
  end
endmodule
```

they have correct line numbers (10, 10, 11).

* Add test for async always block line numbers

* Add comment for review