From f974d59bb193371617a24e4aa9ac4f0d07aced22 Mon Sep 17 00:00:00 2001
From: "Mukund Raghav Sharma (Moko)"
 <68247673+mrsharm@users.noreply.github.com>
Date: Mon, 1 Aug 2022 09:39:18 -0700
Subject: [PATCH] Fixed a WKS specific issue by not clobbering the
 heap_segment_saved_allocated (#72923)

* Fixed the WKS issue by not clobbering the heap_segment_saved_allocated

* Addressed feedback:
---
 src/coreclr/gc/gc.cpp | 21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/src/coreclr/gc/gc.cpp b/src/coreclr/gc/gc.cpp
index e278bba5005f3..67ff74640c7cb 100644
--- a/src/coreclr/gc/gc.cpp
+++ b/src/coreclr/gc/gc.cpp
@@ -28243,6 +28243,16 @@ void gc_heap::add_plug_in_condemned_info (generation* gen, size_t plug_size)
 }
 #endif //FEATURE_EVENT_TRACE
 
+inline void save_allocated(heap_segment* seg)
+{
+#ifndef MULTIPLE_HEAP
+    if (!heap_segment_saved_allocated(seg))
+#endif // !MULTIPLE_HEAP
+    {
+        heap_segment_saved_allocated (seg) = heap_segment_allocated (seg);
+    }
+}
+
 #ifdef _PREFAST_
 #pragma warning(push)
 #pragma warning(disable:21000) // Suppress PREFast warning about overly large function
@@ -28328,6 +28338,7 @@ void gc_heap::plan_phase (int condemned_gen_number)
             heap_segment* fseg = seg;
             do
             {
+                heap_segment_saved_allocated(seg) = 0;
                 if (in_range_for_segment (slow, seg))
                 {
                     uint8_t* start_unmarked = 0;
@@ -28375,7 +28386,7 @@ void gc_heap::plan_phase (int condemned_gen_number)
                         bgc_clear_batch_mark_array_bits ((shigh + Align (size (shigh))), heap_segment_allocated (seg));
                     }
 #endif //BACKGROUND_GC
-                    heap_segment_saved_allocated (seg) = heap_segment_allocated (seg);
+                    save_allocated(seg);
                     heap_segment_allocated (seg) = shigh + Align (size (shigh));
                 }
                 // test if the segment is in the range of [slow, shigh]
@@ -28394,7 +28405,7 @@ void gc_heap::plan_phase (int condemned_gen_number)
 #endif //USE_REGIONS
                     }
 #endif //BACKGROUND_GC
-                    heap_segment_saved_allocated (seg) = heap_segment_allocated (seg);
+                    save_allocated(seg);
                     // shorten it to minimum
                     heap_segment_allocated (seg) =  heap_segment_mem (seg);
                 }
@@ -28428,7 +28439,7 @@ void gc_heap::plan_phase (int condemned_gen_number)
                     bgc_clear_batch_mark_array_bits (start_unmarked, heap_segment_allocated (seg));
                 }
 #endif //BACKGROUND_GC
-                heap_segment_saved_allocated (seg) = heap_segment_allocated (seg);
+                save_allocated(seg);
                 heap_segment_allocated (seg) = start_unmarked;
 
                 seg = heap_segment_next_rw (seg);
@@ -28711,7 +28722,7 @@ void gc_heap::plan_phase (int condemned_gen_number)
 #endif //USE_REGIONS
             {
                 assert (heap_segment_allocated (seg1) == end);
-                heap_segment_saved_allocated (seg1) = heap_segment_allocated (seg1);
+                save_allocated(seg1);
                 heap_segment_allocated (seg1) = plug_end;
                 current_brick = update_brick_table (tree, current_brick, x, plug_end);
                 dprintf (REGIONS_LOG, ("region %Ix-%Ix(%Ix) non SIP",
@@ -31042,7 +31053,7 @@ void gc_heap::sweep_region_in_plan (heap_segment* region,
 #endif //_DEBUG
 
     assert (last_marked_obj_end);
-    heap_segment_saved_allocated (region) = heap_segment_allocated (region);
+    save_allocated(region);
     heap_segment_allocated (region) = last_marked_obj_end;
     heap_segment_plan_allocated (region) = heap_segment_allocated (region);