From c5c0f9b400e55553a0c3ff281b3d172ea488fc37 Mon Sep 17 00:00:00 2001
From: Chia-hung Duan <chiahungduan@google.com>
Date: Wed, 19 Apr 2023 22:58:36 +0000
Subject: [PATCH] [scudo] Support printing the status of cached blocks

The output looks like,
  Stats: SharedTSDs: 2 available; total 8
    Shared TSD[0]:
      00 (    64): cached:   10 max:   26
      32 ( 65552): cached:    1 max:    2
    Shared TSD[1]:
      No block is cached.

Differential Revision: https://reviews.llvm.org/D148755
---
 compiler-rt/lib/scudo/standalone/combined.h        |  1 +
 compiler-rt/lib/scudo/standalone/local_cache.h     | 24 ++++++++++++++++++++++
 .../lib/scudo/standalone/tests/combined_test.cpp   |  2 ++
 compiler-rt/lib/scudo/standalone/tsd_exclusive.h   |  9 ++++++++
 compiler-rt/lib/scudo/standalone/tsd_shared.h      | 15 ++++++++++++++
 5 files changed, 51 insertions(+)

diff --git a/compiler-rt/lib/scudo/standalone/combined.h b/compiler-rt/lib/scudo/standalone/combined.h
index 250eba0..d5365b6 100644
--- a/compiler-rt/lib/scudo/standalone/combined.h
+++ b/compiler-rt/lib/scudo/standalone/combined.h
@@ -1483,6 +1483,7 @@ private:
     Primary.getStats(Str);
     Secondary.getStats(Str);
     Quarantine.getStats(Str);
+    TSDRegistry.getStats(Str);
     return Str->length();
   }
 
diff --git a/compiler-rt/lib/scudo/standalone/local_cache.h b/compiler-rt/lib/scudo/standalone/local_cache.h
index 92869ea..c97095d 100644
--- a/compiler-rt/lib/scudo/standalone/local_cache.h
+++ b/compiler-rt/lib/scudo/standalone/local_cache.h
@@ -14,6 +14,7 @@
 #include "platform.h"
 #include "report.h"
 #include "stats.h"
+#include "string_utils.h"
 
 namespace scudo {
 
@@ -164,6 +165,29 @@ template <class SizeClassAllocator> struct SizeClassAllocatorLocalCache {
 
   LocalStats &getStats() { return Stats; }
 
+  void getStats(ScopedString *Str) {
+    bool EmptyCache = true;
+    for (uptr I = 0; I < NumClasses; ++I) {
+      if (PerClassArray[I].Count == 0)
+        continue;
+
+      EmptyCache = false;
+      // The size of BatchClass is set to 0 intentionally. See the comment in
+      // initCache() for more details.
+      const uptr ClassSize = I == BatchClassId
+                                 ? SizeClassAllocator::getSizeByClassId(I)
+                                 : PerClassArray[I].ClassSize;
+      // Note that the string utils don't support printing u16 thus we cast it
+      // to a common use type uptr.
+      Str->append("    %02zu (%6zu): cached: %4zu max: %4zu\n", I, ClassSize,
+                  static_cast<uptr>(PerClassArray[I].Count),
+                  static_cast<uptr>(PerClassArray[I].MaxCount));
+    }
+
+    if (EmptyCache)
+      Str->append("    No block is cached.\n");
+  }
+
 private:
   static const uptr NumClasses = SizeClassMap::NumClasses;
   static const uptr BatchClassId = SizeClassMap::BatchClassId;
diff --git a/compiler-rt/lib/scudo/standalone/tests/combined_test.cpp b/compiler-rt/lib/scudo/standalone/tests/combined_test.cpp
index 7bf580e..33a309e 100644
--- a/compiler-rt/lib/scudo/standalone/tests/combined_test.cpp
+++ b/compiler-rt/lib/scudo/standalone/tests/combined_test.cpp
@@ -167,6 +167,8 @@ void ScudoCombinedTest<Config>::BasicTest(scudo::uptr SizeLog) {
       Allocator->deallocate(P, Origin, Size);
     }
   }
+
+  Allocator->printStats();
 }
 
 #define SCUDO_MAKE_BASIC_TEST(SizeLog)                                         \
diff --git a/compiler-rt/lib/scudo/standalone/tsd_exclusive.h b/compiler-rt/lib/scudo/standalone/tsd_exclusive.h
index 62da8ae..aca9fc9 100644
--- a/compiler-rt/lib/scudo/standalone/tsd_exclusive.h
+++ b/compiler-rt/lib/scudo/standalone/tsd_exclusive.h
@@ -11,6 +11,8 @@
 
 #include "tsd.h"
 
+#include "string_utils.h"
+
 namespace scudo {
 
 struct ThreadState {
@@ -104,6 +106,13 @@ template <class Allocator> struct TSDRegistryExT {
 
   bool getDisableMemInit() { return State.DisableMemInit; }
 
+  void getStats(ScopedString *Str) {
+    // We don't have a way to iterate all thread local `ThreadTSD`s. Instead of
+    // printing only self `ThreadTSD` which may mislead the usage, we just skip
+    // it.
+    Str->append("Exclusive TSD don't support iterating each TSD\n");
+  }
+
 private:
   // Using minimal initialization allows for global initialization while keeping
   // the thread specific structure untouched. The fallback structure will be
diff --git a/compiler-rt/lib/scudo/standalone/tsd_shared.h b/compiler-rt/lib/scudo/standalone/tsd_shared.h
index 64b3bd8..e193281 100644
--- a/compiler-rt/lib/scudo/standalone/tsd_shared.h
+++ b/compiler-rt/lib/scudo/standalone/tsd_shared.h
@@ -11,6 +11,8 @@
 
 #include "tsd.h"
 
+#include "string_utils.h"
+
 #if SCUDO_HAS_PLATFORM_TLS_SLOT
 // This is a platform-provided header that needs to be on the include path when
 // Scudo is compiled. It must declare a function with the prototype:
@@ -102,6 +104,19 @@ struct TSDRegistrySharedT {
 
   bool getDisableMemInit() const { return *getTlsPtr() & 1; }
 
+  void getStats(ScopedString *Str) EXCLUDES(MutexTSDs) {
+    ScopedLock L(MutexTSDs);
+
+    Str->append("Stats: SharedTSDs: %u available; total %u\n", NumberOfTSDs,
+                TSDsArraySize);
+    for (uptr I = 0; I < NumberOfTSDs; ++I) {
+      TSDs[I].lock();
+      Str->append("  Shared TSD[%zu]:\n", I);
+      TSDs[I].getCache().getStats(Str);
+      TSDs[I].unlock();
+    }
+  }
+
 private:
   ALWAYS_INLINE uptr *getTlsPtr() const {
 #if SCUDO_HAS_PLATFORM_TLS_SLOT
-- 
2.7.4