Some quick code review feedback

src/coreclr/debug/daccess/request.cpp

@@ -2807,7 +2807,7 @@ ClrDataAccess::GetGCHeapStaticData(struct DacpGcHeapDetails *detailsData)
     detailsData->background_saved_highest_address = (CLRDATA_ADDRESS)*g_gcDacGlobals->background_saved_highest_address;
 
     // get bounds for the different generations
-    for (unsigned int i=0; i < *g_gcDacGlobals->max_gen + 2; i++)
+    for (unsigned int i=0; i < DAC_NUMBERGENERATIONS; i++)
     {
         DPTR(dac_generation) generation = GenerationTableIndex(g_gcDacGlobals->generation_table, i);
         detailsData->generation_table[i].start_segment = (CLRDATA_ADDRESS) dac_cast<TADDR>(generation->start_segment);
@@ -2821,7 +2821,7 @@ ClrDataAccess::GetGCHeapStaticData(struct DacpGcHeapDetails *detailsData)
     {
         DPTR(dac_finalize_queue) fq = Dereference(g_gcDacGlobals->finalize_queue);
         DPTR(uint8_t*) fillPointersTable = dac_cast<TADDR>(fq) + offsetof(dac_finalize_queue, m_FillPointers);
-        for (unsigned int i = 0; i<(*g_gcDacGlobals->max_gen + 2 + dac_finalize_queue::ExtraSegCount); i++)
+        for (unsigned int i = 0; i < DAC_NUMBERGENERATIONS + 3; i++)
         {
             detailsData->finalization_fill_pointers[i] = (CLRDATA_ADDRESS)*TableIndex(fillPointersTable, i, sizeof(uint8_t*));
         }

src/coreclr/debug/daccess/request_common.h

@@ -29,10 +29,10 @@ DPTR(T) Dereference(DPTR(T*) ptr)
 // Indexes into the global heap table, returning a TADDR to the requested
 // heap instance.
 inline TADDR
-HeapTableIndex(DPTR(dac_gc_heap**) heaps, size_t index)
+HeapTableIndex(DPTR(opaque_gc_heap**) heaps, size_t index)
 {
-    DPTR(dac_gc_heap*) heap_table = Dereference(heaps);
-    DPTR(dac_gc_heap*) ptr = TableIndex(heap_table, index, sizeof(dac_gc_heap*));
+    DPTR(opaque_gc_heap*) heap_table = Dereference(heaps);
+    DPTR(opaque_gc_heap*) ptr = TableIndex(heap_table, index, sizeof(void*));
     return Dereference(ptr).GetAddr();
 }
 

src/coreclr/debug/daccess/request_svr.cpp

@@ -147,7 +147,7 @@ ClrDataAccess::ServerGCHeapDetails(CLRDATA_ADDRESS heapAddr, DacpGcHeapDetails *
     detailsData->background_saved_highest_address = (CLRDATA_ADDRESS)pHeap->background_saved_highest_address;
 
     // get bounds for the different generations
-    for (unsigned int i=0; i < *g_gcDacGlobals->max_gen + 2; i++)
+    for (unsigned int i=0; i < DAC_NUMBERGENERATIONS; i++)
     {
         DPTR(dac_generation) generation = ServerGenerationTableIndex(heapAddress, i);
         detailsData->generation_table[i].start_segment     = (CLRDATA_ADDRESS)dac_cast<TADDR>(generation->start_segment);
@@ -161,7 +161,7 @@ ClrDataAccess::ServerGCHeapDetails(CLRDATA_ADDRESS heapAddr, DacpGcHeapDetails *
     if (fq.IsValid())
     {
         DPTR(uint8_t*) fillPointersTable = dac_cast<TADDR>(fq) + offsetof(dac_finalize_queue, m_FillPointers);
-        for (unsigned int i = 0; i<(*g_gcDacGlobals->max_gen + 2 + dac_finalize_queue::ExtraSegCount); i++)
+        for (unsigned int i = 0; i < DAC_NUMBERGENERATIONS + 3; i++)
         {
             detailsData->finalization_fill_pointers[i] = (CLRDATA_ADDRESS)*TableIndex(fillPointersTable, i, sizeof(uint8_t*));
         }

src/coreclr/gc/gc.cpp

@@ -45653,7 +45653,7 @@ static int gc_heap_field_offsets[] = {
 #endif // HEAP_ANALYZE
 #else
     gcDacVars->n_heaps = &gc_heap::n_heaps;
-    gcDacVars->g_heaps = reinterpret_cast<dac_gc_heap***>(&gc_heap::g_heaps);
+    gcDacVars->g_heaps = reinterpret_cast<opaque_gc_heap***>(&gc_heap::g_heaps);
     gcDacVars->gc_heap_field_offsets = reinterpret_cast<int**>(&gc_heap_field_offsets);
 #endif // MULTIPLE_HEAPS
 #else

src/coreclr/gc/gcinterface.dac.h

@@ -169,6 +169,10 @@ class dac_gc_heap {
     dac_generation generation_table[1];
 };
 
+struct opaque_gc_heap
+{
+    uint8_t unused;
+};
 
 // The DAC links against six symbols that build as part of the VM DACCESS_COMPILE
 // build. These symbols are considered to be GC-private functions, but the DAC needs

src/coreclr/gc/gcinterface.dacvars.def

@@ -53,7 +53,7 @@ GC_DAC_PTR_VAR    (uint8_t*,              internal_root_array)
 GC_DAC_VAR        (size_t,                internal_root_array_index)
 GC_DAC_VAR        (BOOL,                  heap_analyze_success)
 GC_DAC_VAR        (int,                   n_heaps)
-GC_DAC_PTR_VAR    (dac_gc_heap*,          g_heaps)
+GC_DAC_PTR_VAR    (opaque_gc_heap*,       g_heaps)
 GC_DAC_VAR        (int32_t,               gc_structures_invalid_cnt)
 GC_DAC_ARRAY_VAR  (size_t,                interesting_data_per_heap)
 GC_DAC_ARRAY_VAR  (size_t,                compact_reasons_per_heap)