chore(profiling): prevent strings from GC'ed whose string_views are p…

…assed to native side [backport 2.11] (#10826)

Backport 23a54ce from #10812 to 2.11.

## Checklist
- [x] PR author has checked that all the criteria below are met
- The PR description includes an overview of the change
- The PR description articulates the motivation for the change
- The change includes tests OR the PR description describes a testing
strategy
- The PR description notes risks associated with the change, if any
- Newly-added code is easy to change
- The change follows the [library release note
guidelines](https://ddtrace.readthedocs.io/en/stable/releasenotes.html)
- The change includes or references documentation updates if necessary
- Backport labels are set (if
[applicable](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting))

## Reviewer Checklist
- [x] Reviewer has checked that all the criteria below are met 
- Title is accurate
- All changes are related to the pull request's stated goal
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[API](https://ddtrace.readthedocs.io/en/stable/versioning.html#interfaces)
changes
- Testing strategy adequately addresses listed risks
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- If necessary, author has acknowledged and discussed the performance
implications of this PR as reported in the benchmarks PR comment
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[release branch maintenance
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Co-authored-by: Taegyun Kim <[email protected]>

ddtrace/internal/datadog/profiling/ddup/_ddup.pyx

@@ -168,9 +168,16 @@ def upload() -> None:
     processor = ddtrace.tracer._endpoint_call_counter_span_processor
     endpoint_counts, endpoint_to_span_ids = processor.reset()
 
+    # We want to make sure that the endpoint_bytes strings outlive the for loops
+    # below and prevent them to be GC'ed. We do this by storing them in a list.
+    # This is necessary because we pass string_views to the C++ code, which is
+    # a view into the original string. If the original string is GC'ed, the view
+    # will point to garbage.
+    endpoint_bytes_list = []
     cdef map[int64_t, string_view] span_ids_to_endpoints = map[int64_t, string_view]()
     for endpoint, span_ids in endpoint_to_span_ids.items():
         endpoint_bytes = ensure_binary_or_empty(endpoint)
+        endpoint_bytes_list.append(endpoint_bytes)
         for span_id in span_ids:
             span_ids_to_endpoints.insert(
                 pair[int64_t, string_view](
@@ -183,6 +190,7 @@ def upload() -> None:
     cdef map[string_view, int64_t] trace_endpoints_to_counts = map[string_view, int64_t]()
     for endpoint, cnt in endpoint_counts.items():
         endpoint_bytes = ensure_binary_or_empty(endpoint)
+        endpoint_bytes_list.append(endpoint_bytes)
         trace_endpoints_to_counts.insert(pair[string_view, int64_t](
             string_view(<const char*>endpoint_bytes, len(endpoint_bytes)),
             clamp_to_int64_unsigned(cnt)