[vm] Label virtual memory allocations on Android.

TEST=examine /proc/pid/smaps and Observatory's "process memory" page
Change-Id: I03922c9c604ceef8901a8946481d0ccc31110b72
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/213289
Commit-Queue: Ryan Macnak <[email protected]>
Reviewed-by: Ben Konyi <[email protected]>

Author: rmacnak-google

runtime/vm/service.cc

@@ -4283,10 +4283,17 @@ static void AddVMMappings(JSONArray* rss_children) {
       // Skipping a few paths to avoid double counting:
       // (deleted) - memfd dual mapping in Dart heap
       // [heap] - sbrk area, should already included with malloc
-      // <empty> - anonymous mappings, mostly in Dart heap
+      // <empty> - anonymous mappings, mostly in Dart heap (Linux)
+      // [anon:dart-*] - as labelled (Android)
       if ((strcmp(property, "Rss:") == 0) && (size != 0) &&
           (strcmp(path, "(deleted)") != 0) && (strcmp(path, "[heap]") != 0) &&
-          (strcmp(path, "") != 0)) {
+          (strcmp(path, "") != 0) &&
+          (strcmp(path, "[anon:dart-newspace]") != 0) &&
+          (strcmp(path, "[anon:dart-oldspace]") != 0) &&
+          (strcmp(path, "[anon:dart-codespace]") != 0) &&
+          (strcmp(path, "[anon:dart-profiler]") != 0) &&
+          (strcmp(path, "[anon:dart-timeline]") != 0) &&
+          (strcmp(path, "[anon:dart-zone]") != 0)) {
         bool updated = false;
         for (intptr_t i = 0; i < mappings.length(); i++) {
           if (strcmp(mappings[i].path, path) == 0) {

runtime/vm/virtual_memory_posix.cc

@@ -15,6 +15,10 @@
 #include <sys/syscall.h>
 #include <unistd.h>
 
+#if defined(DART_HOST_OS_ANDROID)
+#include <sys/prctl.h>
+#endif
+
 #include "platform/assert.h"
 #include "platform/utils.h"
 #include "vm/heap/pages.h"
@@ -433,6 +437,10 @@ VirtualMemory* VirtualMemory::AllocateAligned(intptr_t size,
     return nullptr;
   }
 
+#if defined(DART_HOST_OS_ANDROID)
+  prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, address, size, name);
+#endif
+
   MemoryRegion region(reinterpret_cast<void*>(address), size);
   return new VirtualMemory(region, region);
 }