Mesa (master): ralloc: Hook up C++ destructors to ralloc when necessary.

[Francisco Jerez]

Module: Mesa
Branch: master
Commit: d18477deea5364847ca6d4be1ce6baa6c8c3fa9c
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=d18477deea5364847ca6d4be1ce6baa6c8c3fa9c

Author: Francisco Jerez <currojerez at riseup.net>
Date:   Wed Oct  9 11:02:51 2013 -0700

ralloc: Hook up C++ destructors to ralloc when necessary.

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.

Reviewed-by: Ian Romanick <ian.d.romanick at intel.com>

---

 src/glsl/ralloc.h |   14 ++++++++++++++
 1 files changed, 14 insertions(+), 0 deletions(-)

diff --git a/src/glsl/ralloc.h b/src/glsl/ralloc.h
index 31682d5..4581a7a 100644
--- a/src/glsl/ralloc.h
+++ b/src/glsl/ralloc.h
@@ -415,15 +415,29 @@ 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);                                                    \
    }