Fix entry resolution for main(String[]) method

[zhengyu123]

What does this PR do?:
Fix a logic error in resolving main(String[]) entry frame.

Motivation:
Bug fix.

Additional Notes:

How to test the change?:
Regular CI

For Datadog employees:

• If this PR touches code that signs or publishes builds or packages, or handles
  credentials of any kind, I've requested a security review (run the dd:platform-security-review
  skill, or file a request via the PSEC review form).
  bewaire also runs automatically on every PR.
• This PR doesn't touch any of that.
• JIRA: PROF-15781

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[dd-octo-sts]

Scan-Build Report

User:	runner@runnervmzvulz
Working Directory:	/home/runner/work/java-profiler/java-profiler/ddprof-lib/src/test/make
Command Line:	make -j4 all
Clang Version:	Ubuntu clang version 18.1.3 (1ubuntu1)
Date:	Mon Aug 17 17:44:13 2026

Bug Summary

Bug Type	Quantity	Display?
All Bugs	1
Logic error
Dereference of null pointer	1

Reports

Bug Group	Bug Type ▾	File	Function/Method	Line	Path Length
Logic error	Dereference of null pointer	profiler.h	findLibraryByAddress	523	28

[dd-octo-sts]

✅ All 40 integration tests passed

📊 Dashboard · 👷 Pipeline · 📦 777cc2c1

[datadog-official]

🔄 Datadog auto-retried 2 jobs - 1 passed on retry

_{This comment will be updated automatically if new data arrives.
🔗 Commit SHA: 777cc2c | Docs | Datadog PR Page | Give us feedback!}

[dd-octo-sts]

CI Test Results

Run: #32051499171 | Commit: 08f2da3 | Duration: 15m 6s (longest job)

✅ All 32 test jobs passed

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

Summary: Total: 32 | Passed: 32 | Failed: 0

---

Updated: 2026-08-17 17:59:53 UTC

[chatgpt-codex-connector]

💡 Codex Review

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Reviewed commit: 03c8d05836

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[chatgpt-codex-connector]

💡 Codex Review

java-profiler/ddprof-lib/src/main/cpp/flightRecorder.cpp

Line 276 in 777cc2c

strncmp(method_sig, "([Ljava/lang/String;)V", 22) == 0) {

Add regression coverage for main entry detection

Because this commit is a bug fix to the predicate that decides whether a main(String[]) root frame is emitted as non-truncated, the production-only change leaves CI with no failing-before/passing-after check for the descriptor regression that was just fixed. Please add a Java or gtest regression that captures/resolves a public static void main(String[]) frame and asserts the resulting stack trace is treated as an entry frame rather than truncated.

AGENTS.md reference: AGENTS.md:L438-L439

ℹ️ About Codex in GitHub

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• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

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[zhengyu123]

A comprehensive test is indeed needed to verify all entry points, but should be done in separate PR.

[jbachorik]

LGTM