Avoid duplicated read (#77577)

cshung · web-flow · commit a124c1456447 · 2022-10-31T11:57:36.000-07:00
diff --git a/src/coreclr/gc/gc.cpp b/src/coreclr/gc/gc.cpp
@@ -35686,7 +35686,7 @@ void gc_heap::revisit_written_page (uint8_t* page,
                                         no_more_loop_p = TRUE;
                                         goto end_limit;
                                     }
-                                    uint8_t* oo = *poo;
+                                    uint8_t* oo = VolatileLoadWithoutBarrier(poo);
 
                                     num_marked_objects++;
                                     background_mark_object (oo THREAD_NUMBER_ARG);

Original file line number	Diff line number	Diff line change
`@@ -35686,7 +35686,7 @@ void gc_heap::revisit_written_page (uint8_t* page,`
`35686`	`35686`	`no_more_loop_p = TRUE;`
`35687`	`35687`	`goto end_limit;`
`35688`	`35688`	`}`
`35689`		`- uint8_t* oo = *poo;`
	`35689`	`+ uint8_t* oo = VolatileLoadWithoutBarrier(poo);`
`35690`	`35690`
`35691`	`35691`	`num_marked_objects++;`
`35692`	`35692`	`background_mark_object (oo THREAD_NUMBER_ARG);`