Attach to duplicated USDT markers #1341
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Non functional change. Tuples become hard to read after you get enough entries.
We had two codepaths with almost duplicate code. This commit factors out the common code.
Non functional change. Just some small code cleanup.
This commit adds support for duplicated USDT markers. Duplication in this context means identical provider and name. See the later runtime test for an example of how this can occur. With this commit, bpftrace will generate separate programs for each duplicated marker. We need to generate separate programs because the location of the usdt arguments may not be the same in each call site. The later runtime test does not reproduce this behavior but I've observed this happening in production before.
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This PR adds support for duplicated USDT markers. Duplication in
this context means identical provider and name. See the runtime
test for an example of how this can occur.
With this change, bpftrace will generate separate programs for each
duplicated marker. We need to generate separate programs because the
location of the usdt arguments may not be the same in each call site.
The later runtime test does not reproduce this behavior but I've
observed this happening in production before.
Note that a good portion of this PR is light refactoring work. Someone
(probably me) should really refactor the probe generation code. It's
excruciatingly difficult to reason about and extremely easy to make
mistakes. Maybe it could be made better by passing a metadata struct
around instead of trying to guess section names.
Checklist
docs/reference_guide.mdCHANGELOG.md