Adopt ThreadLocal to store ProfiledThread

[zhengyu123]

What does this PR do?:

Motivation:

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[Copilot]

Pull request overview

This PR migrates ProfiledThread storage from a raw pthread_key_t TLS implementation to the project’s ThreadLocal<> wrapper, and wires up an explicit native initialization path so per-thread profiler metadata can be established earlier and more predictably.

Changes:

• Replace ProfiledThread’s pthread_key_t TLS plumbing with ThreadLocal<ProfiledThread*> and adjust initialization APIs accordingly.
• Add Profiler::init() and call it from JavaProfiler_init0() to initialize native state earlier.
• Update JVM support initialization to also validate the ProfiledThread TLS key.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
ddprof-lib/src/test/cpp/ddprof_ut.cpp	Updates unit test to use the new initCurrentThread() return value.
ddprof-lib/src/main/cpp/threadLocalData.h	Switches ProfiledThread to ThreadLocal<> and adjusts initialization/lookup API surface.
ddprof-lib/src/main/cpp/threadLocalData.cpp	Implements the new ThreadLocal<>-backed ProfiledThread initialization and teardown logic.
ddprof-lib/src/main/cpp/profiler.h	Adds Profiler::init() to the public interface.
ddprof-lib/src/main/cpp/profiler.cpp	Implements Profiler::init() and uses initCurrentThread() where needed.
ddprof-lib/src/main/cpp/jvmSupport.cpp	Treats ProfiledThread TLS key validity as part of JVM support initialization readiness.
ddprof-lib/src/main/cpp/javaApi.cpp	Calls Profiler::init() from JNI init and updates several JNI entry points to use the new thread initialization behavior.

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[datadog-official]

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⚠️ Warnings

🚦 8 Pipeline jobs failed

CI Run | test-matrix / test-linux-glibc-amd64 (11-j9, debug)     

CI Run | test-matrix / test-linux-glibc-amd64 (17-j9, debug)     

DataDog/java-profiler | reliability-chaos-aarch64: [profiler+tracer, tcmalloc, 21.0.3-tem]     

View all 8 failed jobs.

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[dd-octo-sts]

CI Test Results

Run: #28904774596 | Commit: f7c6db4 | Duration: 13m 43s (longest job)

❌ 2 of 32 test jobs failed

Status Overview

JDK	glibc-aarch64/debug	glibc-amd64/debug	musl-aarch64/debug	musl-amd64/debug
8	-	✅	-	-
8-ibm	-	✅	-	-
8-j9	✅	✅	-	-
8-librca	-	-	✅	✅
8-orcl	-	✅	-	-
11	-	✅	-	-
11-j9	✅	❌	-	-
11-librca	-	-	✅	✅
17	✅	✅	-	-
17-graal	✅	✅	-	-
17-j9	✅	❌	-	-
17-librca	-	-	✅	✅
21	✅	✅	-	-
21-graal	✅	✅	-	-
21-librca	-	-	✅	✅
25	✅	✅	-	-
25-graal	✅	✅	-	-
25-librca	-	-	✅	✅

Legend: ✅ passed | ❌ failed | ⚪ skipped | 🚫 cancelled

Failed Tests

glibc-amd64/debug / 11-j9

Job: View logs

No detailed failure information available. Check the job logs.

glibc-amd64/debug / 17-j9

Job: View logs

No detailed failure information available. Check the job logs.

Summary: Total: 32 | Passed: 30 | Failed: 2

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Updated: 2026-07-07 23:21:20 UTC

[dd-octo-sts]

Reliability & Chaos Results

❌ 1 failure(s) detected Pipeline: https://gitlab.ddbuild.io/DataDog/java-profiler/-/pipelines/123405477

❌ chaos: profiler gmalloc amd64 21 0 3 temXchaos

Chaos harness crashed (RC=124)