yosys/techlibs/xilinx
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
..
tests xilinx: Add simulation model for DSP48 (Virtex 4). 2020-01-29 01:40:00 +01:00
.gitignore Added support for initialized xilinx brams 2015-04-06 17:07:10 +02:00
Makefile.inc xilinx: Use dfflegalize. 2020-07-09 18:54:23 +02:00
abc9_model.v abc9_ops: add -prep_bypass for auto bypass boxes; refactor 2020-05-14 10:33:56 -07:00
arith_map.v verilog: significant block scoping improvements 2021-01-31 09:42:09 -05:00
brams_init.py synth_xilinx: Initial Spartan 6 block RAM inference support. 2019-07-11 14:45:48 +02:00
cells_map.v xilinx: Use dfflegalize. 2020-07-09 18:54:23 +02:00
cells_sim.v xilinx: Add FDRSE_1, FDCPE_1. 2021-01-27 00:32:00 +01:00
cells_xtra.py xilinx: Add some missing blackbox cells. 2020-12-21 05:34:26 +01:00
cells_xtra.v xilinx: Add some missing blackbox cells. 2020-12-21 05:34:26 +01:00
ff_map.v xilinx: Use dfflegalize. 2020-07-09 18:54:23 +02:00
lut4_lutrams.txt xilinx: Add support for LUT RAM on LUT4-based devices. 2020-02-07 09:03:22 +01:00
lut6_lutrams.txt xilinx: Add support for LUT RAM on LUT4-based devices. 2020-02-07 09:03:22 +01:00
lut_map.v Add force_downto and force_upto wire attributes. 2020-05-19 01:42:40 +02:00
lutrams_map.v Merge branch 'eddie/xilinx_lutram' of github.com:YosysHQ/yosys into eddie/xilinx_lutram 2019-12-16 12:06:47 -08:00
mux_map.v Add force_downto and force_upto wire attributes. 2020-05-19 01:42:40 +02:00
synth_xilinx.cc Replace opt_rmdff with opt_dff. 2020-08-07 13:21:03 +02:00
xc2v_brams.txt xilinx: Add block RAM mapping for Virtex 2* and Spartan 3*. 2020-02-07 01:00:29 +01:00
xc2v_brams_map.v xilinx: Add block RAM mapping for Virtex 2* and Spartan 3*. 2020-02-07 01:00:29 +01:00
xc3s_mult_map.v xilinx: Support multiplier mapping for all families. 2019-10-22 18:06:57 +02:00
xc3sa_brams.txt xilinx: Add block RAM mapping for Virtex 2* and Spartan 3*. 2020-02-07 01:00:29 +01:00
xc3sda_brams.txt xilinx: Add block RAM mapping for Virtex 2* and Spartan 3*. 2020-02-07 01:00:29 +01:00
xc3sda_dsp_map.v xilinx_dsp: Initial DSP48A/DSP48A1 support. 2019-12-22 20:51:14 +01:00
xc4v_dsp_map.v xilinx: Support multiplier mapping for all families. 2019-10-22 18:06:57 +02:00
xc5v_dsp_map.v xilinx: Support multiplier mapping for all families. 2019-10-22 18:06:57 +02:00
xc6s_brams.txt xilinx: Add block RAM mapping for Virtex 2* and Spartan 3*. 2020-02-07 01:00:29 +01:00
xc6s_brams_map.v xilinx: Add block RAM mapping for Virtex 2* and Spartan 3*. 2020-02-07 01:00:29 +01:00
xc6s_dsp_map.v xilinx_dsp: Initial DSP48A/DSP48A1 support. 2019-12-22 20:51:14 +01:00
xc7_brams_map.v xilinx: Add block RAM mapping for Virtex 2* and Spartan 3*. 2020-02-07 01:00:29 +01:00
xc7_dsp_map.v xilinx: do not make DSP48E1 a whitebox for ABC9 by default (#2325) 2020-09-23 09:15:24 -07:00
xc7_xcu_brams.txt xilinx: Add block RAM mapping for Virtex 2* and Spartan 3*. 2020-02-07 01:00:29 +01:00
xcu_brams_map.v xilinx: Add block RAM mapping for Virtex 2* and Spartan 3*. 2020-02-07 01:00:29 +01:00
xcu_dsp_map.v xilinx: Support multiplier mapping for all families. 2019-10-22 18:06:57 +02:00
xcup_urams.txt xilinx: Add URAM288 mapping for xcup 2019-10-23 11:47:44 +01:00
xcup_urams_map.v xilinx: Add URAM288 mapping for xcup 2019-10-23 11:47:44 +01:00
xilinx_dffopt.cc xilinx_dffopt: Don't crash on missing IS_*_INVERTED. 2021-01-27 00:32:00 +01:00