Configuring Pragmas

Pragmas are comments with meta data used by various vendors. These pragmas communicate information which can change how vendor tools interpret code.

There does not appear to be a standard for defining pragmas. This presents a challenge to detecting them across all vendor tools.

To address this challenge, pragmas can be defined using regular expressions in a configuration file.

There are three types of pragmas: open, close, and single.

The open and close pragmas form a pair. For example:

-- synthesis translate_off
-- synthesis translate_on

The first pragma is an open type, while the second is a close type.

A single type of pragma stands on its own. For example:

-- synthesis library <my_lib>

The default expressions are defined as:

            - '^\\s*--\\s+synthesis\\s+translate_off\\s*$'
            - '^\\s*--\\s+RTL_SYNTHESIS\\s+OFF\\s*$'
            - '^\\s*--vhdl_comp_off]\\s*$'
            - '^\\s*--\\s+synthesis\\s+translate_on\\s*$'
            - '^\\s*--\\s+RTL_SYNTHESIS\\s+ON\\s*$'
            - '^\\s*--vhdl_comp_on]\\s*$'
            - '^\\s*--\\s+synthesis\\s+\\w+\\s*$'
            - '^\\s*--\\s+synthesis\\s+\\w+\\s+\\w+\\s*$'
            - '^\\s*--\\s+pragma\\s+\\w+\\s*$'
            - '^\\s*--\\s+pragma\\s+\\w+\\s+\\w+\\s*$'
            - '^\\s*--\\s+altera\\s+\\w+\\s*$'
            - '^\\s*--\\s+synopsys\\s+\\w+\\s*$'
            - '^\\s*--\\s+synopsys\\s+\\w+\\s+\\w+\\s*$'
            - '^\\s*--\\s+xilinx\\s+\\w+\\s*$'
            - "^\\s*--\\s+xilinx\\s+\\w+\\s+\\w+\\s*$"

Each pattern will be applied to a line in the source file. If a match is detected, the comment will be converted into a pragma. Otherwise the comment will be left as a comment.

Rules Using Pragmas