Added dtrace probe for tracing object allocations.

This currently only traces classes allocated in the Ruby side of things. String,
Array and other allocations are not yet tracked.

vm/builtin/class.cpp

@@ -11,6 +11,8 @@
 #include "object_utils.hpp"
 #include "object_memory.hpp"
 #include "on_stack.hpp"
+#include "call_frame.hpp"
+#include "dtrace/dtrace.h"
 
 namespace rubinius {
 
@@ -139,6 +141,9 @@ namespace rubinius {
 #ifdef RBX_GC_STRESS
       state->shared().gc_soon();
 #endif
+
+      RUBINIUS_OBJECT_ALLOCATE_HOOK(state, new_obj, calling_environment);
+
       return new_obj;
     } else if(!type_info_->allow_user_allocate || kind_of<SingletonClass>(this)) {
       std::ostringstream msg;
@@ -165,6 +170,9 @@ namespace rubinius {
 #ifdef RBX_GC_STRESS
       state->shared().gc_soon();
 #endif
+
+      RUBINIUS_OBJECT_ALLOCATE_HOOK(state, new_obj, calling_environment);
+
       return new_obj;
     } else {
       // type_info_->type is neither PackedObject nor Object, so use the
@@ -179,6 +187,9 @@ namespace rubinius {
 #ifdef RBX_GC_STRESS
       state->shared().gc_soon();
 #endif
+
+      RUBINIUS_OBJECT_ALLOCATE_HOOK(state, new_obj, calling_environment);
+
       return new_obj;
     }
   }

vm/dtrace/dtrace.h

@@ -25,6 +25,26 @@
   } \
 } \
 
+#define RUBINIUS_OBJECT_ALLOCATE_HOOK(state, obj, frame) \
+{ \
+  if(RUBINIUS_OBJECT_ALLOCATE_ENABLED()) { \
+    Class* mod = obj->direct_class(state); \
+    RBX_DTRACE_CONST char* module_name = \
+      const_cast<RBX_DTRACE_CONST char*>(mod->debug_str(state).c_str()); \
+    RBX_DTRACE_CONST char* file_name = \
+      const_cast<RBX_DTRACE_CONST char *>("<unknown>"); \
+    int line = 0; \
+    if(frame) { \
+      Symbol* file = frame->file(state); \
+      if(!file->nil_p()) { \
+        file_name = const_cast<RBX_DTRACE_CONST char*>(file->debug_str(state).c_str()); \
+      } \
+      line = frame->line(state); \
+    } \
+    RUBINIUS_OBJECT_ALLOCATE(module_name, file_name, line); \
+  } \
+} \
+
 #else
 #include "dtrace/probes_dummy.h"
 #define RUBINIUS_METHOD_HOOK(probe, state, mod, method, previous) do { } while(0)

vm/dtrace/probes.d

@@ -83,6 +83,17 @@ provider rubinius {
   */
   probe gc__end(int full);
 
+  /*
+    rubinius::object-allocate(classname, filename, lineno)
+
+    Fired when a new object is allocated
+
+    * `classname` the name of the class/module that was allocated
+    * `filename` the path to the file where the object was allocated
+    * `lineno` the line number of the allocation
+   */
+  probe object__allocate(const char *, const char *, int);
+
   /*
      rubinius:::thread-start(thread_id);
 

vm/dtrace/probes_dummy.h

@@ -46,6 +46,8 @@ extern "C" {
 #define RUBINIUS_THREAD_STOP_ENABLED() 0
 #define RUBINIUS_THREAD_STOP(arg0, arg1, arg2) do { } while(0)
 
+#define RUBINIUS_OBJECT_ALLOCATE_ENABLED() 0
+#define RUBINIUS_OBJECT_ALLOCATE(arg0, arg1. arg2) do { } while(0)
 
 #define RUBINIUS_JIT_FUNCTION_BEGIN_ENABLED() 0
 #define RUBINIUS_JIT_FUNCTION_BEGIN(arg0, arg1, arg2, arg3) do { } while(0)