Implement Objects on VWA

This commit implements Objects on Variable Width Allocation. This allows
Objects with more ivars to be embedded (i.e. contents directly follow the
object header) which improves performance through better cache locality.

1 files changed, 14 insertions, 7 deletions

diff --git a/yjit/src/codegen.rs b/yjit/src/codegen.rs
index 84f4ff4897..9cd69cd340 100644
--- a/yjit/src/codegen.rs
+++ b/yjit/src/codegen.rs
@@ -1966,9 +1966,17 @@ fn gen_get_ivar(
         ctx.stack_pop(1);
     }
 
+    if USE_RVARGC != 0 {
+        // Check that the ivar table is big enough
+        // Check that the slot is inside the ivar table (num_slots > index)
+        let num_slots = mem_opnd(32, REG0, ROBJECT_OFFSET_NUMIV);
+        cmp(cb, num_slots, uimm_opnd(ivar_index as u64));
+        jle_ptr(cb, counted_exit!(ocb, side_exit, getivar_idx_out_of_range));
+    }
+
     // Compile time self is embedded and the ivar index lands within the object
     let test_result = unsafe { FL_TEST_RAW(comptime_receiver, VALUE(ROBJECT_EMBED.as_usize())) != VALUE(0) };
-    if test_result && ivar_index < (ROBJECT_EMBED_LEN_MAX.as_usize()) {
+    if test_result {
         // See ROBJECT_IVPTR() from include/ruby/internal/core/robject.h
 
         // Guard that self is embedded
@@ -1988,7 +1996,7 @@ fn gen_get_ivar(
         );
 
         // Load the variable
-        let offs = RUBY_OFFSET_ROBJECT_AS_ARY + (ivar_index * SIZEOF_VALUE) as i32;
+        let offs = ROBJECT_OFFSET_AS_ARY + (ivar_index * SIZEOF_VALUE) as i32;
         let ivar_opnd = mem_opnd(64, REG0, offs);
         mov(cb, REG1, ivar_opnd);
 
@@ -2019,17 +2027,16 @@ fn gen_get_ivar(
             side_exit,
         );
 
-        // Check that the extended table is big enough
-        if ivar_index > (ROBJECT_EMBED_LEN_MAX.as_usize()) {
+        if USE_RVARGC == 0 {
+            // Check that the extended table is big enough
             // Check that the slot is inside the extended table (num_slots > index)
-            let num_slots = mem_opnd(32, REG0, RUBY_OFFSET_ROBJECT_AS_HEAP_NUMIV);
-
+            let num_slots = mem_opnd(32, REG0, ROBJECT_OFFSET_NUMIV);
             cmp(cb, num_slots, uimm_opnd(ivar_index as u64));
             jle_ptr(cb, counted_exit!(ocb, side_exit, getivar_idx_out_of_range));
         }
 
         // Get a pointer to the extended table
-        let tbl_opnd = mem_opnd(64, REG0, RUBY_OFFSET_ROBJECT_AS_HEAP_IVPTR);
+        let tbl_opnd = mem_opnd(64, REG0, ROBJECT_OFFSET_AS_HEAP_IVPTR);
         mov(cb, REG0, tbl_opnd);
 
         // Read the ivar from the extended table