[Mesa-dev] [PATCH 2/2] ralloc: Hook up C++ destructors to ralloc when necessary.

[Francisco Jerez]

This patch makes sure that class destructors are called as they should
be when a C++ object allocated by ralloc is released.

Based on a previous patch by Kenneth Graunke, but it doesn't exhibit
the ~0.8% performance regression in shader compilation times because
we now use the HAS_TRIVIAL_DESTRUCTOR() macro to detect the typical
case where the indirect function call can be avoided because the
object's destructor doesn't need to do anything.
---
 src/glsl/ralloc.h | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/src/glsl/ralloc.h b/src/glsl/ralloc.h
index 31682d5..57af9a4 100644
--- a/src/glsl/ralloc.h
+++ b/src/glsl/ralloc.h
@@ -415,15 +415,28 @@ bool ralloc_vasprintf_append(char **str, const char *fmt, va_list args);
  * which is more idiomatic in C++ than calling ralloc.
  */
 #define DECLARE_RALLOC_CXX_OPERATORS(TYPE)                               \
+private:                                                                 \
+   static void _ralloc_destructor(void *p)                               \
+   {                                                                     \
+      reinterpret_cast<TYPE *>(p)->~TYPE();                              \
+   }                                                                     \
+public:                                                                  \
    static void* operator new(size_t size, void *mem_ctx)                 \
    {                                                                     \
       void *p = ralloc_size(mem_ctx, size);                              \
       assert(p != NULL);                                                 \
+      if (!HAS_TRIVIAL_DESTRUCTOR(TYPE))                                 \
+         ralloc_set_destructor(p, _ralloc_destructor);                   \
       return p;                                                          \
    }                                                                     \
                                                                          \
    static void operator delete(void *p)                                  \
    {                                                                     \
+      /* The object's destructor is guaranteed to have already been      \
+       * called by the delete operator at this point -- Make sure it's   \
+       * not called again. */                                            \
+      if (!HAS_TRIVIAL_DESTRUCTOR(TYPE))                                 \
+         ralloc_set_destructor(p, NULL);                                 \
       ralloc_free(p);                                                    \
    }
 
-- 
1.8.3.4