introduce TransientHeap. [Bug #14858]

* transient_heap.c, transient_heap.h: implement TransientHeap (theap).
  theap is designed for Ruby's object system. theap is like Eden heap
  on generational GC terminology. theap allocation is very fast because
  it only needs to bump up pointer and deallocation is also fast because
  we don't do anything. However we need to evacuate (Copy GC terminology)
  if theap memory is long-lived. Evacuation logic is needed for each type.

  See [Bug #14858] for details.

* array.c: Now, theap for T_ARRAY is supported.

  ary_heap_alloc() tries to allocate memory area from theap. If this trial
  sccesses, this array has theap ptr and RARRAY_TRANSIENT_FLAG is turned on.
  We don't need to free theap ptr.

* ruby.h: RARRAY_CONST_PTR() returns malloc'ed memory area. It menas that
  if ary is allocated at theap, force evacuation to malloc'ed memory.
  It makes programs slow, but very compatible with current code because
  theap memory can be evacuated (theap memory will be recycled).

  If you want to get transient heap ptr, use RARRAY_CONST_PTR_TRANSIENT()
  instead of RARRAY_CONST_PTR(). If you can't understand when evacuation
  will occur, use RARRAY_CONST_PTR().


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65444 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 25 insertions, 5 deletions

diff --git a/include/ruby/ruby.h b/include/ruby/ruby.h
index a05651ac3b..1512e78179 100644
--- a/include/ruby/ruby.h
+++ b/include/ruby/ruby.h
@@ -1020,12 +1020,15 @@ enum ruby_rarray_flags {
     RARRAY_EMBED_LEN_MASK = (RUBY_FL_USER4|RUBY_FL_USER3),
     RARRAY_EMBED_LEN_SHIFT = (RUBY_FL_USHIFT+3),
 
+    RARRAY_TRANSIENT_FLAG = RUBY_FL_USER13,
+
     RARRAY_ENUM_END
 };
 #define RARRAY_EMBED_FLAG (VALUE)RARRAY_EMBED_FLAG
 #define RARRAY_EMBED_LEN_MASK (VALUE)RARRAY_EMBED_LEN_MASK
 #define RARRAY_EMBED_LEN_MAX RARRAY_EMBED_LEN_MAX
 #define RARRAY_EMBED_LEN_SHIFT RARRAY_EMBED_LEN_SHIFT
+#define RARRAY_TRANSIENT_FLAG RARRAY_TRANSIENT_FLAG
 struct RArray {
     struct RBasic basic;
     union {
@@ -1046,9 +1049,14 @@ struct RArray {
 #define RARRAY_LEN(a) rb_array_len(a)
 #define RARRAY_LENINT(ary) rb_long2int(RARRAY_LEN(ary))
 #define RARRAY_CONST_PTR(a) rb_array_const_ptr(a)
+#define RARRAY_CONST_PTR_TRANSIENT(a) rb_array_const_ptr_transient(a)
+#define RARRAY_TRANSIENT_P(ary) FL_TEST_RAW((ary), RARRAY_TRANSIENT_FLAG)
+
+VALUE *rb_ary_ptr_use_start(VALUE ary);
+void rb_ary_ptr_use_end(VALUE ary);
 
-#define RARRAY_PTR_USE_START(a) ((VALUE *)RARRAY_CONST_PTR(a))
-#define RARRAY_PTR_USE_END(a) /* */
+#define RARRAY_PTR_USE_START(a) rb_ary_ptr_use_start(a)
+#define RARRAY_PTR_USE_END(a) rb_ary_ptr_use_end(a)
 
 #define RARRAY_PTR_USE(ary, ptr_name, expr) do { \
     const VALUE _ary = (ary); \
@@ -1057,11 +1065,12 @@ struct RArray {
     RARRAY_PTR_USE_END(_ary); \
 } while (0)
 
-#define RARRAY_AREF(a, i)    (RARRAY_CONST_PTR(a)[i])
+#define RARRAY_AREF(a, i) (RARRAY_CONST_PTR_TRANSIENT(a)[i])
 #define RARRAY_ASET(a, i, v) do { \
     const VALUE _ary = (a); \
+    const VALUE _v = (v); \
     VALUE *ptr = (VALUE *)RARRAY_PTR_USE_START(_ary); \
-    RB_OBJ_WRITE(_ary, &ptr[i], (v)); \
+    RB_OBJ_WRITE(_ary, &ptr[i], _v); \
     RARRAY_PTR_USE_END(_ary); \
 } while (0)
 
@@ -2110,12 +2119,23 @@ rb_array_len(VALUE a)
 #endif
 
 static inline const VALUE *
-rb_array_const_ptr(VALUE a)
+rb_array_const_ptr_transient(VALUE a)
 {
     return FIX_CONST_VALUE_PTR((RBASIC(a)->flags & RARRAY_EMBED_FLAG) ?
 	RARRAY(a)->as.ary : RARRAY(a)->as.heap.ptr);
 }
 
+void rb_ary_detransient(VALUE a);
+
+static inline const VALUE *
+rb_array_const_ptr(VALUE a)
+{
+    if (RARRAY_TRANSIENT_P(a)) {
+        rb_ary_detransient(a);
+    }
+    return rb_array_const_ptr_transient(a);
+}
+
 #if defined(EXTLIB) && defined(USE_DLN_A_OUT)
 /* hook for external modules */
 static char *dln_libs_to_be_linked[] = { EXTLIB, 0 };