[hwasan] Export memory stats through /proc/$PID/maps.

Adds a line to /proc/$PID/maps with more or less up-to-date memory
stats of the process.

llvm-svn: 341735

compiler-rt/lib/hwasan/hwasan.cc

@@ -171,22 +171,53 @@ static void HWAsanCheckFailed(const char *file, int line, const char *cond,
   Die();
 }
 
-static void HwasanPrintMemoryUsage() {
+static constexpr uptr kMemoryUsageBufferSize = 4096;
+
+static void HwasanFormatMemoryUsage(InternalScopedString &s) {
   auto thread_stats = Thread::GetThreadStats();
   auto *sds = StackDepotGetStats();
   AllocatorStatCounters asc;
   GetAllocatorStats(asc);
-  Printf(
+  s.append(
       "HWASAN pid: %d rss: %zd threads: %zd stacks: %zd"
       " thr_aux: %zd stack_depot: %zd uniq_stacks: %zd"
-      " heap: %zd\n",
+      " heap: %zd",
       internal_getpid(), GetRSS(), thread_stats.n_live_threads,
       thread_stats.total_stack_size,
       thread_stats.n_live_threads * Thread::MemoryUsedPerThread(),
-      sds->allocated, sds->n_uniq_ids,
-      asc[AllocatorStatMapped]);
+      sds->allocated, sds->n_uniq_ids, asc[AllocatorStatMapped]);
 }
 
+#if SANITIZER_ANDROID
+static char *memory_usage_buffer = nullptr;
+
+#define PR_SET_VMA 0x53564d41
+#define PR_SET_VMA_ANON_NAME 0
+
+static void InitMemoryUsage() {
+  memory_usage_buffer =
+      (char *)MmapOrDie(kMemoryUsageBufferSize, "memory usage string");
+  CHECK(memory_usage_buffer);
+  memory_usage_buffer[0] = '\0';
+  CHECK(internal_prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME,
+                       (uptr)memory_usage_buffer, kMemoryUsageBufferSize,
+                       (uptr)memory_usage_buffer) == 0);
+}
+
+void UpdateMemoryUsage() {
+  if (!flags()->export_memory_stats)
+    return;
+  if (!memory_usage_buffer)
+    InitMemoryUsage();
+  InternalScopedString s(kMemoryUsageBufferSize);
+  HwasanFormatMemoryUsage(s);
+  internal_strncpy(memory_usage_buffer, s.data(), kMemoryUsageBufferSize - 1);
+  memory_usage_buffer[kMemoryUsageBufferSize - 1] = '\0';
+}
+#else
+void UpdateMemoryUsage() {}
+#endif
+
 } // namespace __hwasan
 
 // Interface.
@@ -455,7 +486,11 @@ void __hwasan_handle_longjmp(const void *sp_dst) {
   TagMemory(sp, dst - sp, 0);
 }
 
-void __hwasan_print_memory_usage() { HwasanPrintMemoryUsage(); }
+void __hwasan_print_memory_usage() {
+  InternalScopedString s(kMemoryUsageBufferSize);
+  HwasanFormatMemoryUsage(s);
+  Printf("%s\n", s.data());
+}
 
 static const u8 kFallbackTag = 0xBB;
 

compiler-rt/lib/hwasan/hwasan.h

@@ -145,6 +145,8 @@ void HwasanTSDInit();
 
 void HwasanOnDeadlySignal(int signo, void *info, void *context);
 
+void UpdateMemoryUsage();
+
 }  // namespace __hwasan
 
 #define HWASAN_MALLOC_HOOK(ptr, size)       \

compiler-rt/lib/hwasan/hwasan_allocator.h

@@ -34,7 +34,7 @@ struct Metadata {
 };
 
 struct HwasanMapUnmapCallback {
-  void OnMap(uptr p, uptr size) const {}
+  void OnMap(uptr p, uptr size) const { UpdateMemoryUsage(); }
   void OnUnmap(uptr p, uptr size) const {
     // We are about to unmap a chunk of user memory.
     // It can return as user-requested mmap() or another thread stack.

compiler-rt/lib/hwasan/hwasan_flags.inc

@@ -49,3 +49,5 @@ HWASAN_FLAG(int, heap_history_size, 1023,
           "The number of heap (de)allocations remembered per thread. "
           "Affects the quality of heap-related reports, but not the ability "
           "to find bugs.")
+HWASAN_FLAG(bool, export_memory_stats, true,
+            "Export up-to-date memory stats through /proc")

compiler-rt/test/hwasan/TestCases/print-memory-usage-android.c

@@ -0,0 +1,13 @@
+// Tests __hwasan_print_memory_usage through /proc/$PID/maps.
+// RUN: %clang_hwasan %s -o %t && %env_hwasan_opts=export_memory_stats=1 %run %t 2>&1 | FileCheck %s
+// REQUIRES: android
+
+#include <stdlib.h>
+#include <stdio.h>
+
+int main() {
+  char cmd[1024];
+  snprintf(cmd, sizeof(cmd), "cat /proc/%d/maps", getpid());
+  system(cmd);
+  // CHECK: HWASAN pid: [[PID:[0-9]*]] rss: {{.*}} threads: 1 stacks: [[STACKS:[0-9]*]] thr_aux: {{.*}} stack_depot: {{.*}} uniq_stacks: [[UNIQ_STACKS:[0-9]*]] heap: [[HEAP:[0-9]*]]
+}