Commit Graph

10 Commits

Author SHA1 Message Date
whitequark baf1875307
Merge pull request from zachjs/unnamed-genblk
verilog: significant block scoping improvements
2021-02-04 09:57:28 +00:00
Zachary Snow fe74b0cd95 verilog: significant block scoping improvements
This change set contains a number of bug fixes and improvements related to
scoping and resolution in generate and procedural blocks. While many of the
frontend changes are interdependent, it may be possible bring the techmap
changes in under a separate PR.

Declarations within unnamed generate blocks previously encountered issues
because the data declarations were left un-prefixed, breaking proper scoping.
The LRM outlines behavior for generating names for unnamed generate blocks. The
original goal was to add this implicit labelling, but doing so exposed a number
of issues downstream. Additional testing highlighted other closely related scope
resolution issues, which have been fixed. This change also adds support for
block item declarations within unnamed blocks in SystemVerilog mode.

1. Unlabled generate blocks are now implicitly named according to the LRM in
   `label_genblks`, which is invoked at the beginning of module elaboration
2. The Verilog parser no longer wraps explicitly named generate blocks in a
   synthetic unnamed generate block to avoid creating extra hierarchy levels
   where they should not exist
3. The techmap phase now allows special control identifiers to be used outside
   of the topmost scope, which is necessary because such wires and cells often
   appear in unlabeled generate blocks, which now prefix the declarations within
4. Some techlibs required modifications because they relied on the previous
   invalid scope resolution behavior
5. `expand_genblock` has been simplified, now only expanding the outermost
   scope, completely deferring the inspection and elaboration of nested scopes;
   names are now resolved by looking in the innermost scope and stepping outward
6. Loop variables now always become localparams during unrolling, allowing them
   to be resolved and shadowed like any other identifier
7. Identifiers in synthetic function call scopes are now prefixed and resolved
   in largely the same manner as other blocks
     before: `$func$\func_01$tests/simple/scopes.blk.v:60$5$\blk\x`
      after: `\func_01$func$tests/simple/scopes.v:60$5.blk.x`
8. Support identifiers referencing a local generate scope nested more
   than 1 level deep, i.e. `B.C.x` while within generate scope `A`, or using a
   prefix of a current or parent scope, i.e. `B.C.D.x` while in `A.B`, `A.B.C`,
   or `A.B.C.D`
9. Variables can now be declared within unnamed blocks in SystemVerilog mode

Addresses the following issues: 656, 2423, 2493
2021-01-31 09:42:09 -05:00
dalance 84ecb321b4 Fix begin/end in generate 2020-11-11 12:03:37 +09:00
Zachary Snow 6127f22788 Module name scope support 2020-08-20 20:15:08 -04:00
Zachary Snow c3e95eb1ab Fix generate scoping issues
- expand_genblock defers prefixing of items within named sub-blocks
- Allow partially-qualified references to local scopes
- Handle shadowing within generate blocks
- Resolve generate scope references within tasks and functions
- Apply generate scoping to genvars
- Resolves , resolves 
2020-07-31 20:32:47 -06:00
Eddie Hung c20adc5263 Add test 2019-06-20 16:07:22 -07:00
Zachary Snow a5f4b83637 fix local name resolution in prefix constructs 2019-03-18 20:43:20 -04:00
Clifford Wolf 50f22ff30c Renamed some of the test cases in tests/simple to avoid name collisions 2014-07-25 13:01:45 +02:00
Clifford Wolf 4a4a3fc337 Various improvements in support for generate statements 2013-12-04 21:06:54 +01:00
Clifford Wolf 7764d0ba1d initial import 2013-01-05 11:13:26 +01:00