Allocator: make leak detection work with static variables

When definining static variables that own memory, you should
use the "construct on first use" idiom. Otherwise, you'll get
a warning when Blender exits.

More details are provided in D8354.

Differential Revision: https://developer.blender.org/D8354

7 files changed, 93 insertions, 0 deletions

diff --git a/intern/guardedalloc/CMakeLists.txt b/intern/guardedalloc/CMakeLists.txt
index cb24df65ba0..1ab365a376a 100644
--- a/intern/guardedalloc/CMakeLists.txt
+++ b/intern/guardedalloc/CMakeLists.txt
@@ -28,6 +28,7 @@ set(INC_SYS
 )
 
 set(SRC
+  ./intern/leak_detector.cc
   ./intern/mallocn.c
   ./intern/mallocn_guarded_impl.c
   ./intern/mallocn_lockfree_impl.c
diff --git a/intern/guardedalloc/MEM_guardedalloc.h b/intern/guardedalloc/MEM_guardedalloc.h
index 1318aa10697..604330bd1d3 100644
--- a/intern/guardedalloc/MEM_guardedalloc.h
+++ b/intern/guardedalloc/MEM_guardedalloc.h
@@ -211,6 +211,10 @@ extern size_t (*MEM_get_peak_memory)(void) ATTR_WARN_UNUSED_RESULT;
 extern const char *(*MEM_name_ptr)(void *vmemh);
 #endif
 
+/** This should be called as early as possible in the program. When it has been called, information
+ * about memory leaks will be printed on exit. */
+void MEM_initialize_memleak_detection(void);
+
 /* Switch allocator to slower but fully guarded mode. */
 void MEM_use_guarded_allocator(void);
 
diff --git a/intern/guardedalloc/intern/leak_detector.cc b/intern/guardedalloc/intern/leak_detector.cc
new file mode 100644
index 00000000000..4b2689ee28c
--- /dev/null
+++ b/intern/guardedalloc/intern/leak_detector.cc
@@ -0,0 +1,61 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+/** \file
+ * \ingroup MEM
+ */
+
+#include "MEM_guardedalloc.h"
+#include "mallocn_intern.h"
+
+bool leak_detector_has_run = false;
+char free_after_leak_detection_message[] =
+    "Freeing memory after the leak detector has run. This can happen when using "
+    "static variables in C++ that are defined outside of functions. To fix this "
+    "error, use the 'construct on first use' idiom.";
+
+namespace {
+class MemLeakPrinter {
+ public:
+  ~MemLeakPrinter()
+  {
+    leak_detector_has_run = true;
+    const uint leaked_blocks = MEM_get_memory_blocks_in_use();
+    if (leaked_blocks == 0) {
+      return;
+    }
+    const size_t mem_in_use = MEM_get_memory_in_use();
+    printf("Error: Not freed memory blocks: %u, total unfreed memory %f MB\n",
+           leaked_blocks,
+           (double)mem_in_use / 1024 / 1024);
+    MEM_printmemlist();
+  }
+};
+}  // namespace
+
+void MEM_initialize_memleak_detection(void)
+{
+  /**
+   * This variable is constructed when this function is first called. This should happen as soon as
+   * possible when the program starts.
+   *
+   * It is destructed when the program exits. During destruction, it will print information about
+   * leaked memory blocks. Static variables are destructed in reversed order of their
+   * construction. Therefore, all static variables that own memory have to be constructed after
+   * this function has been called.
+   */
+  static MemLeakPrinter printer;
+}
diff --git a/intern/guardedalloc/intern/mallocn_guarded_impl.c b/intern/guardedalloc/intern/mallocn_guarded_impl.c
index 5e523204020..2c207935e43 100644
--- a/intern/guardedalloc/intern/mallocn_guarded_impl.c
+++ b/intern/guardedalloc/intern/mallocn_guarded_impl.c
@@ -898,6 +898,10 @@ void MEM_guarded_freeN(void *vmemh)
     memt = (MemTail *)(((char *)memh) + sizeof(MemHead) + memh->len);
     if (memt->tag3 == MEMTAG3) {
 
+      if (leak_detector_has_run) {
+        MemorY_ErroR(memh->name, free_after_leak_detection_message);
+      }
+
       memh->tag1 = MEMFREE;
       memh->tag2 = MEMFREE;
       memt->tag3 = MEMFREE;
diff --git a/intern/guardedalloc/intern/mallocn_inline.h b/intern/guardedalloc/intern/mallocn_inline.h
index f8bb7861fc9..4e73eb9bad6 100644
--- a/intern/guardedalloc/intern/mallocn_inline.h
+++ b/intern/guardedalloc/intern/mallocn_inline.h
@@ -33,6 +33,10 @@
 #ifndef __MALLOCN_INLINE_H__
 #define __MALLOCN_INLINE_H__
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 MEM_INLINE bool MEM_size_safe_multiply(size_t a, size_t b, size_t *result)
 {
   /* A size_t with its high-half bits all set to 1. */
@@ -52,4 +56,8 @@ MEM_INLINE bool MEM_size_safe_multiply(size_t a, size_t b, size_t *result)
   return ((high_bits & (a | b)) == 0 || (*result / b == a));
 }
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* __MALLOCN_INLINE_H__ */
diff --git a/intern/guardedalloc/intern/mallocn_intern.h b/intern/guardedalloc/intern/mallocn_intern.h
index ef8845a66b3..8fc3e432157 100644
--- a/intern/guardedalloc/intern/mallocn_intern.h
+++ b/intern/guardedalloc/intern/mallocn_intern.h
@@ -100,11 +100,18 @@ size_t malloc_usable_size(void *ptr);
 
 #include "mallocn_inline.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #define ALIGNED_MALLOC_MINIMUM_ALIGNMENT sizeof(void *)
 
 void *aligned_malloc(size_t size, size_t alignment);
 void aligned_free(void *ptr);
 
+extern bool leak_detector_has_run;
+extern char free_after_leak_detection_message[];
+
 /* Prototypes for counted allocator functions */
 size_t MEM_lockfree_allocN_len(const void *vmemh) ATTR_WARN_UNUSED_RESULT;
 void MEM_lockfree_freeN(void *vmemh);
@@ -191,4 +198,8 @@ size_t MEM_guarded_get_peak_memory(void) ATTR_WARN_UNUSED_RESULT;
 const char *MEM_guarded_name_ptr(void *vmemh);
 #endif
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* __MALLOCN_INTERN_H__ */
diff --git a/intern/guardedalloc/intern/mallocn_lockfree_impl.c b/intern/guardedalloc/intern/mallocn_lockfree_impl.c
index 205cc688d72..282c852fedd 100644
--- a/intern/guardedalloc/intern/mallocn_lockfree_impl.c
+++ b/intern/guardedalloc/intern/mallocn_lockfree_impl.c
@@ -101,6 +101,10 @@ size_t MEM_lockfree_allocN_len(const void *vmemh)
 
 void MEM_lockfree_freeN(void *vmemh)
 {
+  if (leak_detector_has_run) {
+    print_error(free_after_leak_detection_message);
+  }
+
   MemHead *memh = MEMHEAD_FROM_PTR(vmemh);
   size_t len = MEM_lockfree_allocN_len(vmemh);