Guarded allocator: Function to rename block for debugging

We have plenty of sorta generic functions, that allocate memory with
some generic name for debugging. When such a function is called and the
memory leaks, it may be unclear which call to it allocated the unfreed
memory (and thus which execution path leads to the leak).

The added function is only available if `NDEBUG` is not defined.

Differential Revision: https://developer.blender.org/D15605

Reviewed by: Sergey Sharybin, Bastien Montagne

5 files changed, 32 insertions, 0 deletions

diff --git a/intern/guardedalloc/MEM_guardedalloc.h b/intern/guardedalloc/MEM_guardedalloc.h
index fca19fb9731..64987548a11 100644
--- a/intern/guardedalloc/MEM_guardedalloc.h
+++ b/intern/guardedalloc/MEM_guardedalloc.h
@@ -199,6 +199,15 @@ extern size_t (*MEM_get_peak_memory)(void) ATTR_WARN_UNUSED_RESULT;
 
 #ifndef NDEBUG
 extern const char *(*MEM_name_ptr)(void *vmemh);
+/**
+ * Change the debugging name/string assigned to the memory allocated at \a vmemh. Only affects the
+ * guarded allocator. The name must be a static string, because only a pointer to it is stored!
+ *
+ * Handy when debugging leaking memory allocated by some often called, generic function with a
+ * unspecific name. A caller with more info can set a more specific name, and see which call to the
+ * generic function allocates the leaking memory.
+ */
+extern void (*MEM_name_ptr_set)(void *vmemh, const char *str) ATTR_NONNULL();
 #endif
 
 /**
diff --git a/intern/guardedalloc/intern/mallocn.c b/intern/guardedalloc/intern/mallocn.c
index f7979168799..63f06ced31d 100644
--- a/intern/guardedalloc/intern/mallocn.c
+++ b/intern/guardedalloc/intern/mallocn.c
@@ -49,6 +49,7 @@ size_t (*MEM_get_peak_memory)(void) = MEM_lockfree_get_peak_memory;
 
 #ifndef NDEBUG
 const char *(*MEM_name_ptr)(void *vmemh) = MEM_lockfree_name_ptr;
+void (*MEM_name_ptr_set)(void *vmemh, const char *str) = MEM_lockfree_name_ptr_set;
 #endif
 
 void *aligned_malloc(size_t size, size_t alignment)
@@ -128,6 +129,7 @@ void MEM_use_lockfree_allocator(void)
 
 #ifndef NDEBUG
   MEM_name_ptr = MEM_lockfree_name_ptr;
+  MEM_name_ptr_set = MEM_lockfree_name_ptr_set;
 #endif
 }
 
@@ -159,5 +161,6 @@ void MEM_use_guarded_allocator(void)
 
 #ifndef NDEBUG
   MEM_name_ptr = MEM_guarded_name_ptr;
+  MEM_name_ptr_set = MEM_guarded_name_ptr_set;
 #endif
 }
diff --git a/intern/guardedalloc/intern/mallocn_guarded_impl.c b/intern/guardedalloc/intern/mallocn_guarded_impl.c
index 8bf1680e6f8..cd4b99ecde8 100644
--- a/intern/guardedalloc/intern/mallocn_guarded_impl.c
+++ b/intern/guardedalloc/intern/mallocn_guarded_impl.c
@@ -1199,4 +1199,18 @@ const char *MEM_guarded_name_ptr(void *vmemh)
 
   return "MEM_guarded_name_ptr(NULL)";
 }
+
+void MEM_guarded_name_ptr_set(void *vmemh, const char *str)
+{
+  if (!vmemh) {
+    return;
+  }
+
+  MemHead *memh = vmemh;
+  memh--;
+  memh->name = str;
+  if (memh->prev) {
+    MEMNEXT(memh->prev)->nextname = str;
+  }
+}
 #endif /* NDEBUG */
diff --git a/intern/guardedalloc/intern/mallocn_intern.h b/intern/guardedalloc/intern/mallocn_intern.h
index f8b16ff6ddf..ce5683a04ae 100644
--- a/intern/guardedalloc/intern/mallocn_intern.h
+++ b/intern/guardedalloc/intern/mallocn_intern.h
@@ -131,6 +131,7 @@ void MEM_lockfree_reset_peak_memory(void);
 size_t MEM_lockfree_get_peak_memory(void) ATTR_WARN_UNUSED_RESULT;
 #ifndef NDEBUG
 const char *MEM_lockfree_name_ptr(void *vmemh);
+void MEM_lockfree_name_ptr_set(void *vmemh, const char *str);
 #endif
 
 /* Prototypes for fully guarded allocator functions */
@@ -174,6 +175,7 @@ void MEM_guarded_reset_peak_memory(void);
 size_t MEM_guarded_get_peak_memory(void) ATTR_WARN_UNUSED_RESULT;
 #ifndef NDEBUG
 const char *MEM_guarded_name_ptr(void *vmemh);
+void MEM_guarded_name_ptr_set(void *vmemh, const char *str);
 #endif
 
 #ifdef __cplusplus
diff --git a/intern/guardedalloc/intern/mallocn_lockfree_impl.c b/intern/guardedalloc/intern/mallocn_lockfree_impl.c
index 300e2000a14..b5ee539ff4d 100644
--- a/intern/guardedalloc/intern/mallocn_lockfree_impl.c
+++ b/intern/guardedalloc/intern/mallocn_lockfree_impl.c
@@ -426,4 +426,8 @@ const char *MEM_lockfree_name_ptr(void *vmemh)
 
   return "MEM_lockfree_name_ptr(NULL)";
 }
+
+void MEM_lockfree_name_ptr_set(void *UNUSED(vmemh), const char *UNUSED(str))
+{
+}
 #endif /* NDEBUG */