From 4bb1318a4844a48eb9b0bad0995eadc8516d0438 Mon Sep 17 00:00:00 2001
From: Peter Sollich <petersol@microsoft.com>
Date: Sun, 13 Jun 2021 17:25:30 +0200
Subject: [PATCH] Fix profiler\gc\gcbasic test to work with SVR GC on many
 cores. (#54057)

Problem was that we had a fixed size buffer (32 entries), and we may have way more generation bounds than that, especially with regions.

Fix is to heap allocate the buffer if the size of the buffer on the stack is exceeded.
---
 .../gcbasicprofiler/gcbasicprofiler.cpp       | 53 +++++++++++++++----
 1 file changed, 42 insertions(+), 11 deletions(-)

diff --git a/src/tests/profiler/native/gcbasicprofiler/gcbasicprofiler.cpp b/src/tests/profiler/native/gcbasicprofiler/gcbasicprofiler.cpp
index dfea99b45d0..a9f28011eb0 100644
--- a/src/tests/profiler/native/gcbasicprofiler/gcbasicprofiler.cpp
+++ b/src/tests/profiler/native/gcbasicprofiler/gcbasicprofiler.cpp
@@ -66,33 +66,64 @@ HRESULT GCBasicProfiler::GarbageCollectionStarted(int cGenerations, BOOL generat
     if(_gcStarts == 1)
     {
         ULONG nObjectRanges;
-        const ULONG cRanges = 32;
-        COR_PRF_GC_GENERATION_RANGE objectRanges[cRanges];
+        bool fHeapAlloc = false;
+        COR_PRF_GC_GENERATION_RANGE* pObjectRanges = nullptr;
+        {
+            const ULONG cRanges = 32;
+            COR_PRF_GC_GENERATION_RANGE objectRangesStackBuffer[cRanges];
+
+            HRESULT hr = pCorProfilerInfo->GetGenerationBounds(cRanges, &nObjectRanges, objectRangesStackBuffer);
+            if (FAILED(hr))
+            {
+                _failures++;
+                printf("GCBasicProfiler::GarbageCollectionStarted: FAIL: GetGenerationBounds hr=0x%x\n", hr);
+                return S_OK;
+            }
+            if (nObjectRanges <= cRanges)
+            {
+                pObjectRanges = objectRangesStackBuffer;
+            }
+        }
 
-        HRESULT hr = pCorProfilerInfo->GetGenerationBounds(cRanges, &nObjectRanges, objectRanges);
-        if (FAILED(hr))
+        if (pObjectRanges == nullptr)
         {
-            _failures++;
-            printf("GCBasicProfiler::GarbageCollectionStarted: FAIL: GetGenerationBounds hr=0x%x\n", hr);
-            return S_OK;
+            pObjectRanges = new COR_PRF_GC_GENERATION_RANGE[nObjectRanges];
+            if (pObjectRanges == nullptr)
+            {
+                _failures++;
+                printf("Couldn't allocate buffer for generation ranges\n");
+                return S_OK;
+            }
+            fHeapAlloc = true;
+
+            ULONG nObjectRanges2;
+            HRESULT hr = pCorProfilerInfo->GetGenerationBounds(nObjectRanges, &nObjectRanges2, pObjectRanges);
+            if (FAILED(hr) || nObjectRanges != nObjectRanges2)
+            {
+                _failures++;
+                printf("GCBasicProfiler::GarbageCollectionStarted: FAIL: GetGenerationBounds hr=0x%x, %d != %d\n", hr, nObjectRanges, nObjectRanges2);
+                return S_OK;
+            }
         }
         // loop through all ranges
         for (int i = nObjectRanges - 1; i >= 0; i--)
         {
-            if (0 > objectRanges[i].generation || objectRanges[i].generation > 4)
+            if (0 > pObjectRanges[i].generation || pObjectRanges[i].generation > 4)
             {
                 _failures++;
-                printf("GCBasicProfiler::GarbageCollectionStarted: FAIL: invalid generation: %d\n",objectRanges[i].generation);
+                printf("GCBasicProfiler::GarbageCollectionStarted: FAIL: invalid generation: %d\n",pObjectRanges[i].generation);
             }
         }
-        if (nObjectRanges > 3 && objectRanges[2].generation == 2 && objectRanges[2].rangeLength == 0x18 && objectRanges[2].generation == 1)
+        if (nObjectRanges > 3 && pObjectRanges[2].generation == 2 && pObjectRanges[2].rangeLength == 0x18 && pObjectRanges[2].generation == 1)
         {
-            if (objectRanges[3].rangeLength != 0x18)
+            if (pObjectRanges[3].rangeLength != 0x18)
             {
                 _failures++;
                 printf("GCBasicProfiler::GarbageCollectionStarted: FAIL: in the first GC for the segment case, gen 1 should have size 0x18");
             }
         }
+        if (fHeapAlloc)
+            delete[] pObjectRanges;
     }
 
     return S_OK;
-- 
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