This is needed for detecting use before declaration. The lexical scanner
is the only place where we process the source text in strict lexical
order, so do it there.
As Verilog allows modules to span multiple source files, don't reset
the counter when we reset the lexor.
Whilst the wording in the IEEE standards is ambiguous, discussions on
the standards committee mailing lists clarify that an unsized literal is
supposed to be the same size as an integer (as shown in IEEE 1364-2005
table 5-22). The token following the base format character is specified
to be an unsized number. So to maintain compatibility with the standards
and with other tools, if the unsigned number part of an unsized signed
based literal can be represented in less than integer_width bits and the
MSB is a '1', we need to add a leading zero to ensure it is zero-extended
when used in an expression.
This fixes issue #1082.
One variant did, the other variant didn't. As well as being a trap for
the unwary, this gets in the way of using yywarn/VLwarn for non-fatal
"sorry" messages.
Always prefix with "error: ". Capitalise the first word of the main
message unless it's a Verilog keyword. Use VLerror() in preference
to direct output to cerr.
Normally the preprocessor will catch these and report them as undefined
macros. But in case the compiler is run without the preprocessor, also
catch them in the compiler scanner. This will ensure the scanner properly
rejects directives that have additional garbage characters tacked on the
end.
Verilog compiler directives are free-form and, subject to semantic rules,
can appear anywhere in the source code. Whilst it is common practice to
write them on a separate line, we should handle all legal syntax.
Currently typedefs are just a pointer to a data_type_t.
Currently typedefs are implemented by setting the name field of a
data_type_t when a typedef of the type is declared. This works mostly, but
there are some corner cases that can't be supported.
E.g. a typedef of a typedef does not work as it overwrites the name field
of the same data_type_t multiple times.
Forward typedefs can also not be supported since forward typedefs allow to
reference a type before it has been declared.
There are also some problems with type identifier references from a
higher-level scope if there is a type identifier in the current scope with
the same name, but it is declared after the type identifier has been
referenced. E.g. in the following x should be a vector fo width 8, but it
will be a vector of width 4, because while the right type is used it is
elaborated in the wrong scope.
```
localparam A = 8;
typedef logic [A-1:0] T;
module M;
localparam A = 4;
T x;
typedef int T;
endmodule
```
Furthermore typedefs used for the type of ports are elaborated in the wrong
scope.
To handle these corner case issues introduce a data_type_t for typedefs.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The "->" operator is rarely used, but exists. Unfortunately, the syntax
is tied up in a horrible mess with the System Verilog constraint list
syntax. Do some flex magic to make it all work.
Explicit imports should always conflict with local declarations using
the same name. Wildcard imports only conflict if they are referenced
before a local declaration with the same name.
This also unifies the detection of identifier conflicts.
This implements and enforces the full set of rules for determining
timescales in SystemVerilog. The previous relaxation of the rules
that allowed timescales to be redefined within the compilation unit
scope has been removed. Time unit and precision redeclarations are
now recognised after a nested module declaration.
This relies on using the automatically generated name for the unit scope.
This could collide with an escaped identifier, so it would be better to
identify the scope by a reference to the PPackage object, but for now,
do it the easy way.
This adds a -u option to the driver to allow the user to specify that
they want each source file to be treated as a separate compilation
unit, and modifies the compiler to accept a list of files (either on
the command line or via a file specified by a new -F option). This
list of files is then preprocessed and parsed separately, causing all
compiler directives (including macro definitions) to only apply to the
file containing them, as required by the SystemVerilog standard.
Replace explicit comparisons against generation_flag with calls to
the gn_system_verilog helper function, both for code clarity and
to fix a couple of bugs. Also simplify the implementation of the
function, as we already rely on the generation_flag enumeration
being an ordered list.
The bug report was for an assertion failure when a number contained only
a lowline (e.g. 'b_), but the standard says that a number can't start
with a lowline (e.g. 'b_1). The parser already rejected these cases for
decimal numbers, but allowed them through for binary/octal/hex numbers.
To be strictly compliant with the standard and compatible with other
EDA tools, unsized numbers should be treated as having a fixed size
(the same size as an integer). The -gstrict-expr-width option is
extended to allow the user to enable this behaviour.
Cary R
Martin Whitaker
Lars-Peter Clausen
Lloyd Parkes
Stephen Williams
Larry Doolittle