The only difference between "RTLIL" and "ILANG" is that the latter is
the text representation of the former, as opposed to the in-memory
graph representation. This distinction serves no purpose but confuses
people: it is not obvious that the ILANG backend writes RTLIL graphs.
Passes `write_ilang` and `read_ilang` are provided as aliases to
`write_rtlil` and `read_rtlil` for compatibility.
The workflow of debugging fatal pass errors in Yosys is flawed in
three ways:
1. Running Yosys under a debugger is sufficient for the debugger
to catch some fatal errors (segfaults, aborts, STL exceptions)
but not others (`log_error()`, `log_cmd_error()`). This is
neither obvious nor easy to remember.
2. To catch Yosys-specific fatal errors, it is necessary to set
a breakpoint at `logv_error_with_prefix()`, or at least,
`logv_error()`. This is neither obvious nor easy to remember,
and GDB's autocomplete takes many seconds to suggest function
names due to the large amount of symbols in Yosys.
3. If a breakpoint is not set and Yosys encounters with such
a fatal error, the process terminates. When debugging a crash
that takes a long time to reproduce (or a nondeterministic crash)
this can waste a significant amount of time.
To solve this problem, add a macro `YS_DEBUGTRAP` that acts as a hard
breakpoint (if available), and a macro `YS_DEBUGTRAP_IF_DEBUGGING`
that acts as a hard breakpoint only if debugger is present.
Then, use `YS_DEBUGTRAP_IF_DEBUGGING` in `logv_error_with_prefix()`
to obviate the need for a breakpoint on nearly every platform.
Co-Authored-By: Alberto Gonzalez <boqwxp@airmail.cc>
(IEEE1800-2017 section 20.11)
This PR allows us to use $info/$warning/$error/$fatal **at elaboration time** within a generate block.
This is very useful to stop a synthesis of a parametrized block when an
illegal combination of parameters is chosen.
o Provide log_file_warning() and log_file_error() that prefix the log
message with <filename>:<lineno>: to be easily picked up by IDEs that
need to step through errors.
o Simplify some duplicate logging code in kernel/log.cc
o Use the new log functions in genrtlil.
