[ICorProfiler] Add new API to enumerate GC Heap objects

src/coreclr/gc/gc.cpp

@@ -52052,6 +52052,38 @@ void GCHeap::DiagWalkHeap (walk_fn fn, void* context, int gen_number, bool walk_
     gc_heap::walk_heap (fn, context, gen_number, walk_large_object_heap_p);
 }
 
+// Walking the GC Heap requires that the EE is suspended and all heap allocation contexts are fixed.
+// DiagWalkHeap is invoked only during a GC, where both requirements are met.
+// So DiagWalkHeapWithACHandling facilitates a GC Heap walk outside of a GC by handling allocation contexts logic,
+// and it leaves the responsibility of suspending and resuming EE to the callers.
+void GCHeap::DiagWalkHeapWithACHandling (walk_fn fn, void* context, int gen_number, bool walk_large_object_heap_p)
+{
+#ifdef MULTIPLE_HEAPS
+    for (int hn = 0; hn < gc_heap::n_heaps; hn++)
+    {
+        gc_heap* hp = gc_heap::g_heaps [hn];
+#else
+    {
+        gc_heap* hp = pGenGCHeap;
+#endif //MULTIPLE_HEAPS
+        hp->fix_allocation_contexts (FALSE);
+    }
+
+    DiagWalkHeap (fn, context, gen_number, walk_large_object_heap_p);
+
+
+#ifdef MULTIPLE_HEAPS
+    for (int hn = 0; hn < gc_heap::n_heaps; hn++)
+    {
+        gc_heap* hp = gc_heap::g_heaps [hn];
+#else
+    {
+        gc_heap* hp = pGenGCHeap;
+#endif //MULTIPLE_HEAPS
+        hp->repair_allocation_contexts (TRUE);
+    }
+}
+
 void GCHeap::DiagWalkFinalizeQueue (void* gc_context, fq_walk_fn fn)
 {
     gc_heap* hp = (gc_heap*)gc_context;

src/coreclr/gc/gcimpl.h

@@ -316,6 +316,8 @@ class GCHeap : public IGCHeapInternal
     virtual void DiagGetGCSettings(EtwGCSettingsInfo* etw_settings);
 
     virtual unsigned int GetGenerationWithRange(Object* object, uint8_t** ppStart, uint8_t** ppAllocated, uint8_t** ppReserved);
+
+    virtual void DiagWalkHeapWithACHandling(walk_fn fn, void* context, int gen_number, bool walk_large_object_heap_p);
 public:
     Object * NextObj (Object * object);
 

src/coreclr/gc/gcinterface.h

@@ -11,7 +11,7 @@
 // The minor version of the IGCHeap interface. Non-breaking changes are required
 // to bump the minor version number. GCs and EEs with minor version number
 // mismatches can still interoperate correctly, with some care.
-#define GC_INTERFACE_MINOR_VERSION 2
+#define GC_INTERFACE_MINOR_VERSION 3
 
 // The major version of the IGCToCLR interface. Breaking changes to this interface
 // require bumps in the major version number.
@@ -1025,6 +1025,9 @@ class IGCHeap {
     virtual uint64_t GetGenerationBudget(int generation) PURE_VIRTUAL
 
     virtual size_t GetLOHThreshold() PURE_VIRTUAL
+
+    // Walk the heap object by object outside of a GC.
+    virtual void DiagWalkHeapWithACHandling(walk_fn fn, void* context, int gen_number, bool walk_large_object_heap_p) PURE_VIRTUAL
 };
 
 #ifdef WRITE_BARRIER_CHECK

src/coreclr/inc/corprof.idl

@@ -861,6 +861,11 @@ typedef enum _COR_PRF_HANDLE_TYPE
 
 typedef void** ObjectHandleID;
 
+/*
+* Callback for each object in the GC Heap
+*/
+typedef BOOL STDMETHODCALLTYPE (* ObjectCallback)(ObjectID object, void* callbackState);
+
 /* -------------------------------------------------------------------------- *
  * Forward declarations
  * -------------------------------------------------------------------------- */
@@ -2651,7 +2656,6 @@ typedef enum
     COR_PRF_CODEGEN_DEBUG_INFO =                0x0003,
 } COR_PRF_CODEGEN_FLAGS;
 
-
 /*
  * The CLR implements the ICorProfilerInfo interface. This interface is
  * used by a code profiler to communicate with the CLR to control event
@@ -4308,6 +4312,47 @@ interface ICorProfilerInfo14 : ICorProfilerInfo13
                 [out] EVENTPIPE_PROVIDER        *pProvider);
 }
 
+[
+    object,
+    uuid(B446462D-BD22-41DD-872D-DC714C49EB56),
+    pointer_default(unique),
+    local
+]
+interface ICorProfilerInfo15 : ICorProfilerInfo14
+{
+    /*
+     * EnumerateGCHeapObjects is a method that iterates over each object in the GC heap.
+     * For each object, it invokes the provided callback function which should return a bool
+     * indicating whether or not enumeration should continue.
+     * Enumerating the GC heap requires suspending the runtime. The profiler may accomplish this
+     * by starting from a state where the runtime is not suspended and by doing one of:
+     *
+     * From the same thread,
+     * Invoking ICorProfilerInfo10::SuspendRuntime()
+     * ...
+     * Invoking ICorProfilerInfo15::EnumerateGCHeapObjects()
+     * ...
+     * Invoking ICorProfilerInfo10::ResumeRuntime()
+     *
+     * or
+     *
+     * Invoke ICorProfilerInfo15::EnumerateGCHeapObjects() on its own, and leverage its
+     * built-in runtime suspension logic.
+     *
+     * Parameters:
+     * - callback: A function pointer to the callback function that will be invoked for each object in the GC heap.
+     *            The callback function should accept an ObjectID and a void pointer as parameters and return a BOOL.
+     * - callbackState: A void pointer that can be used to pass state information to the callback function.
+     *
+     * Returns:
+     * - HRESULT: A code indicating the result of the operation. If the method succeeds,
+     *           it returns S_OK. If it fails, it returns an error code.
+     */
+    HRESULT EnumerateGCHeapObjects(
+        [in] ObjectCallback callback,
+        [in] void* callbackState);
+}
+
 /*
 * This interface lets you iterate over methods in the runtime.
 */

src/coreclr/pal/prebuilt/idl/corprof_i.cpp

@@ -150,6 +150,9 @@ MIDL_DEFINE_GUID(IID, IID_ICorProfilerInfo13,0x6E6C7EE2,0x0701,0x4EC2,0x9D,0x29,
 MIDL_DEFINE_GUID(IID, IID_ICorProfilerInfo14,0xF460E352,0xD76D,0x4FE9,0x83,0x5F,0xF6,0xAF,0x9D,0x6E,0x86,0x2D);
 
 
+MIDL_DEFINE_GUID(IID, IID_ICorProfilerInfo15,0xB446462D,0xBD22,0x41DD,0x87,0x2D,0xDC,0x71,0x4C,0x49,0xEB,0x56);
+
+
 MIDL_DEFINE_GUID(IID, IID_ICorProfilerMethodEnum,0xFCCEE788,0x0088,0x454B,0xA8,0x11,0xC9,0x9F,0x29,0x8D,0x19,0x42);