From ad63b668e22e21c352b852f3119ae98a7acf99f1 Mon Sep 17 00:00:00 2001
From: Jemma Issroff <jemmaissroff@gmail.com>
Date: Mon, 3 Oct 2022 11:14:32 -0400
Subject: Revert "Revert "This commit implements the Object Shapes technique in
 CRuby.""

This reverts commit 9a6803c90b817f70389cae10d60b50ad752da48f.
---
 shape.h | 150 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 150 insertions(+)
 create mode 100644 shape.h

(limited to 'shape.h')

diff --git a/shape.h b/shape.h
new file mode 100644
index 0000000000..66b8e580c9
--- /dev/null
+++ b/shape.h
@@ -0,0 +1,150 @@
+#ifndef RUBY_SHAPE_H
+#define RUBY_SHAPE_H
+#if (SIZEOF_UINT64_T == SIZEOF_VALUE)
+#define SIZEOF_SHAPE_T 4
+#define SHAPE_IN_BASIC_FLAGS 1
+typedef uint32_t attr_index_t;
+#else
+#define SIZEOF_SHAPE_T 2
+#define SHAPE_IN_BASIC_FLAGS 0
+typedef uint16_t attr_index_t;
+#endif
+
+#define MAX_IVARS (attr_index_t)(-1)
+
+#if RUBY_DEBUG || (defined(VM_CHECK_MODE) && VM_CHECK_MODE > 0)
+#  if SIZEOF_SHAPE_T == 4
+typedef uint32_t shape_id_t;
+# define SHAPE_BITS 16
+#  else
+typedef uint16_t shape_id_t;
+# define SHAPE_BITS 16
+#  endif
+#else
+#  if SIZEOF_SHAPE_T == 4
+typedef uint32_t shape_id_t;
+# define SHAPE_BITS 32
+#  else
+typedef uint16_t shape_id_t;
+# define SHAPE_BITS 16
+#  endif
+#endif
+
+# define SHAPE_MASK (((uintptr_t)1 << SHAPE_BITS) - 1)
+# define SHAPE_FLAG_MASK (((VALUE)-1) >> SHAPE_BITS)
+
+# define SHAPE_FLAG_SHIFT ((SIZEOF_VALUE * 8) - SHAPE_BITS)
+
+# define SHAPE_BITMAP_SIZE 16384
+
+# define MAX_SHAPE_ID (SHAPE_MASK - 1)
+# define INVALID_SHAPE_ID SHAPE_MASK
+# define ROOT_SHAPE_ID 0x0
+# define FROZEN_ROOT_SHAPE_ID 0x1
+
+struct rb_shape {
+    struct rb_shape * parent; // Pointer to the parent
+    struct rb_id_table * edges; // id_table from ID (ivar) to next shape
+    ID edge_name; // ID (ivar) for transition from parent to rb_shape
+    attr_index_t iv_count;
+    uint8_t type;
+};
+
+typedef struct rb_shape rb_shape_t;
+
+enum shape_type {
+    SHAPE_ROOT,
+    SHAPE_IVAR,
+    SHAPE_FROZEN,
+    SHAPE_IVAR_UNDEF,
+};
+
+static inline shape_id_t
+IMEMO_CACHED_SHAPE_ID(VALUE cc)
+{
+    RBIMPL_ASSERT_TYPE((VALUE)cc, RUBY_T_IMEMO);
+    return (shape_id_t)(SHAPE_MASK & (RBASIC(cc)->flags >> SHAPE_FLAG_SHIFT));
+}
+
+static inline void
+IMEMO_SET_CACHED_SHAPE_ID(VALUE cc, shape_id_t shape_id)
+{
+    RBIMPL_ASSERT_TYPE((VALUE)cc, RUBY_T_IMEMO);
+    RBASIC(cc)->flags &= SHAPE_FLAG_MASK;
+    RBASIC(cc)->flags |= ((VALUE)(shape_id) << SHAPE_FLAG_SHIFT);
+}
+
+#if SHAPE_IN_BASIC_FLAGS
+static inline shape_id_t
+RBASIC_SHAPE_ID(VALUE obj)
+{
+    RUBY_ASSERT(!RB_SPECIAL_CONST_P(obj));
+    return (shape_id_t)(SHAPE_MASK & ((RBASIC(obj)->flags) >> SHAPE_FLAG_SHIFT));
+}
+
+static inline void
+RBASIC_SET_SHAPE_ID(VALUE obj, shape_id_t shape_id)
+{
+    // Ractors are occupying the upper 32 bits of flags, but only in debug mode
+    // Object shapes are occupying top bits
+    RBASIC(obj)->flags &= SHAPE_FLAG_MASK;
+    RBASIC(obj)->flags |= ((VALUE)(shape_id) << SHAPE_FLAG_SHIFT);
+}
+
+static inline shape_id_t
+ROBJECT_SHAPE_ID(VALUE obj)
+{
+    RBIMPL_ASSERT_TYPE(obj, RUBY_T_OBJECT);
+    return RBASIC_SHAPE_ID(obj);
+}
+
+static inline void
+ROBJECT_SET_SHAPE_ID(VALUE obj, shape_id_t shape_id)
+{
+    RBIMPL_ASSERT_TYPE(obj, RUBY_T_OBJECT);
+    RBASIC_SET_SHAPE_ID(obj, shape_id);
+}
+
+#else
+
+static inline shape_id_t
+ROBJECT_SHAPE_ID(VALUE obj)
+{
+    RBIMPL_ASSERT_TYPE(obj, RUBY_T_OBJECT);
+    return (shape_id_t)(SHAPE_MASK & (RBASIC(obj)->flags >> SHAPE_FLAG_SHIFT));
+}
+
+static inline void
+ROBJECT_SET_SHAPE_ID(VALUE obj, shape_id_t shape_id)
+{
+    RBASIC(obj)->flags &= SHAPE_FLAG_MASK;
+    RBASIC(obj)->flags |= ((VALUE)(shape_id) << SHAPE_FLAG_SHIFT);
+}
+#endif
+
+bool rb_shape_root_shape_p(rb_shape_t* shape);
+
+rb_shape_t* rb_shape_get_shape_by_id_without_assertion(shape_id_t shape_id);
+
+MJIT_SYMBOL_EXPORT_BEGIN
+rb_shape_t* rb_shape_get_shape_by_id(shape_id_t shape_id);
+void rb_shape_set_shape(VALUE obj, rb_shape_t* shape);
+shape_id_t rb_shape_get_shape_id(VALUE obj);
+rb_shape_t* rb_shape_get_shape(VALUE obj);
+int rb_shape_frozen_shape_p(rb_shape_t* shape);
+void rb_shape_transition_shape_frozen(VALUE obj);
+void rb_shape_transition_shape_remove_ivar(VALUE obj, ID id, rb_shape_t *shape);
+void rb_shape_transition_shape(VALUE obj, ID id, rb_shape_t *shape);
+rb_shape_t* rb_shape_get_next(rb_shape_t* shape, VALUE obj, ID id);
+bool rb_shape_get_iv_index(rb_shape_t * shape, ID id, attr_index_t * value);
+shape_id_t rb_shape_id(rb_shape_t * shape);
+MJIT_SYMBOL_EXPORT_END
+
+rb_shape_t * rb_shape_alloc(ID edge_name, rb_shape_t * parent);
+
+bool rb_shape_set_shape_id(VALUE obj, shape_id_t shape_id);
+
+VALUE rb_obj_debug_shape(VALUE self, VALUE obj);
+VALUE rb_shape_flags_mask(void);
+
+#endif
-- 
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