Consider this SystemVerilog file:
module top(...);
input clk;
input [7:0] data;
input ack;
always @(posedge clk)
if (ack) begin
assert(data != 8'h0a);
end
endmodule
Before this commit, the span for the assert was:
if (ack) begin>
assert(data != 8'h0a)<;
After this commit, the span for the assert is:
if (ack) begin
>assert(data != 8'h0a)<;
This helps editor integrations that only look at the beginning
of the span.
- Add support for assignments within expressions, e.g., `x[y++] = z;` or
`x = (y *= 2) - 1;`. The logic is handled entirely within the parser
by injecting statements into the current procedural block.
- Add support for pre-increment/decrement statements, which are
behaviorally equivalent to post-increment/decrement statements.
- Fix non-standard attribute position used for post-increment/decrement
statements.
(* nowrshmsk *) on a struct / union variable now affects dynamic
bit slice assignments to members of the struct / union.
(* nowrshmsk *) can in some cases yield significant resource savings; the
combination of pipeline shifting and indexed writes is an example of this.
Constructs similar to the one below can benefit from (* nowrshmsk *), and
in addition it is no longer necessary to split out the shift assignments
on separate lines in order to avoid the error message "ERROR: incompatible
mix of lookahead and non-lookahead IDs in LHS expression."
always_ff @(posedge clk) begin
if (rotate) begin
{ v5, v4, v3, v2, v1, v0 } <= { v4, v3, v2, v1, v0, v5 };
if (res) begin
v0.bytes <= '0;
end else if (w) begin
v0.bytes[addr] <= data;
end
end
end
The difference between void functions and tasks is that always_comb's
implicit sensitivity list behaves as if functions were inlined, but
ignores signals read only in tasks. This only matters for event based
simulation, and for synthesis we can treat a void function like a task.
The preprocessor currently destroys double slash containing escaped
identifiers (for example \a//b ). This is due to next_token trying to
convert single line comments (//) into /* */ comments. This then leads
to an unintuitive error message like this:
ERROR: syntax error, unexpected '*'
This patch fixes the error by recognizing escaped identifiers and
returning them as single token. It also adds a testcase.
Yosys works with bison 3.0 (or newer), but not bison 2.7 (the previous
release). Ideally, we would require "3" rather than "3.0" to give a
better error message, but bison 2.3, which still ships with macOS, does
not support major-only version requirements. With this change, building
with an outdated bison yields: `frontends/rtlil/rtlil_parser.y:25.10-14:
require bison 3.0, but have 2.3`.
This enables the usage of declarations of wand or wor with a base type
of logic, integer, or a typename. Note that declarations of nets with
2-state base types is still permitted, in violation of the spec.
- Root AST_PREFIX nodes are now subject to genblk expansion to allow
them to refer to a locally-visible generate block
- Part selects on AST_PREFIX member leafs can now refer to generate
block items (previously would not resolve and raise an error)
- Add source location information to AST_PREFIX nodes
This is accomplished by generating a unique name for the genvar,
renaming references to the genvar only in the loop's initialization,
guard, and incrementation, and finally adding a localparam inside the
loop body with the original name so that the genvar can be shadowed as
expected.
- User-defined types must be data types. Using a net type (e.g. wire) is
a syntax error.
- User-defined types without a net type are always variables (i.e.
logic).
- Nets and variables can now be explicitly declared using user-defined
types:
typedef logic [1:0] W;
wire W w;
typedef logic [1:0] V;
var V v;
Fixes#2846
This doesn't do anything useful yet: the patch just adds support for
the syntax to the lexer and parser and adds some tests to check the
syntax parses properly. This generates AST nodes, but doesn't yet
generate RTLIL.
Since our existing hierarchical_identifier parser doesn't allow bit
selects (so you can't do something like foo[1].bar[2].baz), I've also
not added support for a trailing bit select (the "constant_bit_select"
non-terminal in "bind_target_instance" in the spec). If we turn out to
need this in future, we'll want to augment hierarchical_identifier and
its other users too.
Note that you can't easily use the BNF from the spec:
bind_directive ::=
"bind" bind_target_scope [ : bind_target_instance_list]
bind_instantiation ;
| "bind" bind_target_instance bind_instantiation ;
even if you fix the lookahead problem, because code like this matches
both branches in the BNF:
bind a b b_i (.*);
The problem is that 'a' could either be a module name or a degenerate
hierarchical reference. This seems to be a genuine syntactic
ambiguity, which the spec resolves (p739) by saying that we have to
wait until resolution time (the hierarchy pass) and take whatever is
defined, treating 'a' as an instance name if it names both an instance
and a module.
To keep the parser simple, it currently accepts this invalid syntax:
bind a.b : c d e (.*);
This is invalid because we're in the first branch of the BNF above, so
the "a.b" term should match bind_target_scope: a module or interface
identifier, not an arbitrary hierarchical identifier.
This will fail in the hierarchy pass (when it's implemented in a
future patch).
- disallow [gen]blocks with an end label but not begin label
- check validity of module end label
- fix memory leak of package name and end label
- fix memory leak of module end label
This was actually a ticking UB bomb: after running the parser, the type
maps contain pointers to children of the current AST, which is
recursively deleted after the pass has executed. This leaves the
pointers in user_type_stack dangling, which just happened to never be a
problem due to another bug that causes typedefs from higher-level type
maps to never be considered.
Rebuilding the type stack from the design's globals ensures the AstNode
pointers are valid.
This breaks the ability to use a global typename as a standard
identifier in a subsequent input file. This is otherwise backwards
compatible, including for sources which previously included conflicting
typedefs in each input file.
Krystine Sherwin
Dag Lem
Catherine
Zachary Snow
Charlotte
Jannis Harder
Miodrag Milanovic
Thomas Sailer
Claire Xen
Marcelina Kościelnicka
Brett Witherspoon
Michael Singer
Rupert Swarbrick
Xiretza