fix(prof): use cached heap in alloc_prof_orig_* functions

[realFlowControl]

Description

A crash report ...

0x55af66530fbf _zend_mm_alloc
0x7fe72dea8401 alloc_prof_orig_alloc (/go/src/github.com/DataDog/apm-reliability/dd-trace-php/profiling/src/allocation/allocation_le83.rs:379)
0x7fe72dea82de alloc_prof_malloc (/go/src/github.com/DataDog/apm-reliability/dd-trace-php/profiling/src/allocation/allocation_le83.rs:350)
0x55af6654bcc5 zend_register_constant
0x7fe72dea7635 execute_internal (/go/src/github.com/DataDog/apm-reliability/dd-trace-php/profiling/src/wall_time.rs:79)
0x55af665cd353 zend_execute
0x55af6655d2c8 zend_execute_scripts
0x55af664f79ae php_execute_script
0x7fe732896305 __libc_start_main
0x55af66248c61 _start

... indicated that _zend_mm_alloc was being called with an invalid heap pointer. This invalid pointer originated from the call to zend::zend_mm_get_heap() within alloc_prof_orig_alloc which is weird and can only mean that "something" changed the current heap via zend_mm_set_heap() after we installed our hooks in RINIT to something invalid, but I could not find any other extension that are known for these kind of things in the crash report.

So: In the end it is the right thing to call the heap that we registered our ZendMM custom handlers in.

Reviewer checklist

• Test coverage seems ok.
• Appropriate labels assigned.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 62.01%. Comparing base (2c70c61) to head (bbcaf45).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3547      +/-   ##
==========================================
- Coverage   62.05%   62.01%   -0.05%     
==========================================
  Files         140      140              
  Lines       13309    13309              
  Branches     1762     1762              
==========================================
- Hits         8259     8253       -6     
- Misses       4262     4268       +6     
  Partials      788      788              

see 2 files with indirect coverage changes

---

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[pr-commenter]

Benchmarks [ profiler ]

Benchmark execution time: 2026-01-14 10:45:16

Comparing candidate commit bbcaf45 in PR branch florian/fix-allocs with baseline commit 2c70c61 in branch master.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 30 metrics, 6 unstable metrics.

[datadog-datadog-prod-us1]

⚠️ Tests

✨ Fix all issues with Cursor

⚠️ Warnings

🧪 1022 Tests failed

    testSearchPhpBinaries from integration.DDTrace\Tests\Integration\PHPInstallerTest (Fix with Cursor)

testSimplePushAndProcess from laravel-58-test.DDTrace\Tests\Integrations\Laravel\V5_8\QueueTest (Datadog) (Fix with Cursor)

Risky Test
phpvfscomposer://tests/vendor/phpunit/phpunit/phpunit:97

testSimplePushAndProcess from laravel-8x-test.DDTrace\Tests\Integrations\Laravel\V8_x\QueueTest (Datadog) (Fix with Cursor)

DDTrace\Tests\Integrations\Laravel\V8_x\QueueTest::testSimplePushAndProcess
Test code or tested code printed unexpected output: spanLinksTraceId: 69677267000000006d451d5fcc4e6203
tid: 6967726700000000
hexProcessTraceId: 6d451d5fcc4e6203
hexProcessSpanId: ce87241695527950
processTraceId: 7873731820813967875
processSpanId: 14881903173082184016

phpvfscomposer://tests/vendor/phpunit/phpunit/phpunit:106

View all

ℹ️ Info

❄️ No new flaky tests detected

_{This comment will be updated automatically if new data arrives.
🔗 Commit SHA: bbcaf45 | Docs | Datadog PR Page | Was this helpful? Give us feedback!}

[realFlowControl]

Let's wait for #3560 get merged and fix the flaky profiling test first