Provide the user with a hint of what caused an out of memory error.
And explain that some memory policies, like selinux deny_execmem
might cause Permission denied errors.
Add an err argument to out_of_memory_NORETURN. And change
am_shadow_alloc to return a SysRes (all three callers were already
checking for errors and calling out_of_memory_NORETURN).
Users shouldn't ever see this, but it's useful to distinguish this
malformed data file case from the missing symbol case (which is still
shown as `???`).
It's currently written in C, but `cg_annotate` and `cg_diff` are written in
Python. It's better to have them all in the same language.
The good news is that the Python code is 4.5x shorter than the C code.
The bad news is that the Python code is roughly 3x slower than the C
code. But `cg_merge` isn't used that often, so I think it's a reasonable
trade-off.
For all the same reasons I rewrote `cg_annotate` in Python.
The commit also moves the Python "build" steps into
`auxprogs/pybuild.sh`, for easy sharing.
Finally, it very slightly tweaks the whitespace in the output of
`cg_annotate`.
- Every section now has a heading with the long `----` lines above and
below.
- Event names are always shown below that heading, rather than within
it.
- Each Unreadable file now gets its own section, much like files that
lack any data.
These tests generate a varying number of errors per argument
depending on the platform and compiler.
The filter just prints the first unique error stanza which
allows 8 expecteds to be removed.
Currently their width is mostly hard-wired in a quick and dirty fashion.
This commit does them properly, so:
- all columns are always the right width, even ones with really large
percentages
- things like `( 1.00%)` are now `(1.00%)`
- any percentages that would involve a division by zero now show as
`(n/a)` rather than `( 0.00%)`
Perl was a reasonable choice for `cg_annotate` in 2002, but not in 2023.
Also, the existing structure of the code is not good. These two things
make it hard to modify `cg_annotate` in any significant way.
Benefits of the change:
- Now written in a language that is (a) nice, and (b) not moribund.
- Easier to maintain, due to (a) abovementioned better language, (b)
better code structure, and (c) better language tooling, such as
formatters, type checkers, and linters.
- The new version is a little shorter.
- It runs about 2x faster.
- Argument handling is more standard. E.g. things like `--context 2`,
`--auto`, `--no-auto` are supported. (The old forms that require `=`
are still supported, though the `=yes`/`=no` forms are deprecated.)
The behaviour and output of the new version is identical for typical
uses, but there are some very minor changes for edge cases, which nobody
is likely to notice. For example:
- The file format is slightly changed: I removed support for '.'
counts, which had the same meaning as '0'. This was a feature that
Cachegrind never used, and the old script handled it inconsistently.
- The new version will abort on a malformed data line. The old version
would just print a warning and continue.
The commit also adds a new test `ann3` that tests many parts of
`cg_annotate` that weren't tested previously, and tweaks the existing
`ann2` test.
