[scudo] Adding an interface function to print allocator stats

Summary:
This adds `__scudo_print_stats` as an interface function to display the Primary
and Secondary allocator statistics for Scudo.

Reviewers: alekseyshl, flowerhack

Reviewed By: alekseyshl

Subscribers: delcypher, llvm-commits, #sanitizers

Differential Revision: https://reviews.llvm.org/D46016

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@330857 91177308-0d34-0410-b5e6-96231b3b80d8

5 files changed, 43 insertions, 0 deletions

diff --git a/include/sanitizer/scudo_interface.h b/include/sanitizer/scudo_interface.h
index 25979fb23..be605f1d7 100644
--- a/include/sanitizer/scudo_interface.h
+++ b/include/sanitizer/scudo_interface.h
@@ -27,6 +27,11 @@ extern "C" {
   // can be removed by setting LimitMb to 0. This function's parameters should
   // be fully trusted to avoid security mishaps.
   void __scudo_set_rss_limit(size_t LimitMb, int HardLimit);
+
+  // This function outputs various allocator statistics for both the Primary
+  // and Secondary allocators, including memory usage, number of allocations
+  // and deallocations.
+  void __scudo_print_stats(void);
 #ifdef __cplusplus
 }  // extern "C"
 #endif
diff --git a/lib/scudo/scudo_allocator.cpp b/lib/scudo/scudo_allocator.cpp
index e0f78a015..c72ac8601 100644
--- a/lib/scudo/scudo_allocator.cpp
+++ b/lib/scudo/scudo_allocator.cpp
@@ -594,6 +594,11 @@ struct ScudoAllocator {
       SoftRssLimitMb = LimitMb;
     CheckRssLimit = HardRssLimitMb || SoftRssLimitMb;
   }
+
+  void printStats() {
+    initThreadMaybe();
+    BackendAllocator.printStats();
+  }
 };
 
 static ScudoAllocator Instance(LINKER_INITIALIZED);
@@ -743,3 +748,7 @@ void __scudo_set_rss_limit(uptr LimitMb, s32 HardLimit) {
     return;
   Instance.setRssLimit(LimitMb, !!HardLimit);
 }
+
+void __scudo_print_stats() {
+  Instance.printStats();
+}
diff --git a/lib/scudo/scudo_allocator_combined.h b/lib/scudo/scudo_allocator_combined.h
index 1c8bb3f11..d22f2a377 100644
--- a/lib/scudo/scudo_allocator_combined.h
+++ b/lib/scudo/scudo_allocator_combined.h
@@ -61,6 +61,11 @@ class ScudoCombinedAllocator {
     Stats.Get(StatType);
   }
 
+  void printStats() {
+    Primary.PrintStats();
+    Secondary.PrintStats();
+  }
+
  private:
   PrimaryAllocator Primary;
   SecondaryAllocator Secondary;
diff --git a/lib/scudo/scudo_interface_internal.h b/lib/scudo/scudo_interface_internal.h
index e2c63db23..3e520a50c 100644
--- a/lib/scudo/scudo_interface_internal.h
+++ b/lib/scudo/scudo_interface_internal.h
@@ -25,6 +25,9 @@ const char* __scudo_default_options();
 
 SANITIZER_INTERFACE_ATTRIBUTE
 void __scudo_set_rss_limit(uptr LimitMb, s32 HardLimit);
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void __scudo_print_stats();
 }  // extern "C"
 
 #endif  // SCUDO_INTERFACE_INTERNAL_H_
diff --git a/test/scudo/stats.c b/test/scudo/stats.c
new file mode 100644
index 000000000..e7cc78ff0
--- /dev/null
+++ b/test/scudo/stats.c
@@ -0,0 +1,21 @@
+// RUN: %clang_scudo %s -o %t
+// RUN: %run %t 2>&1 | FileCheck %s
+
+// Tests that the allocator stats printing function exists and outputs
+// "something". Currently that "something" is fairly nebulous, as the 32-bit
+// primary doesn't output anything, and for the 64-bit one it's highly dependent
+// on the size class map and potential library allocations. So keep it very
+// generic for now.
+
+#include <stdlib.h>
+
+#include <sanitizer/scudo_interface.h>
+
+int main(int argc, char **argv)
+{
+  free(malloc(1U));
+  __scudo_print_stats();
+  return 0;
+}
+
+// CHECK: Stats: