Initial support of opt_getconstant_path

Merged: https://github.com/ruby/ruby/pull/7448

lib/ruby_vm/mjit/insn_compiler.rb

@@ -23,7 +23,7 @@ module RubyVM::MJIT
       asm.incr_counter(:mjit_insns_count)
       asm.comment("Insn: #{insn.name}")
 
-      # 45/101
+      # 46/101
       case insn.name
       when :nop then nop(jit, ctx, asm)
       when :getlocal then getlocal(jit, ctx, asm)
@@ -37,7 +37,7 @@ module RubyVM::MJIT
       when :setinstancevariable then setinstancevariable(jit, ctx, asm)
       # getclassvariable
       # setclassvariable
-      # opt_getconstant_path
+      when :opt_getconstant_path then opt_getconstant_path(jit, ctx, asm)
       # getconstant
       # setconstant
       # getglobal
@@ -209,7 +209,47 @@ module RubyVM::MJIT
 
     # getclassvariable
     # setclassvariable
-    # opt_getconstant_path
+
+    # @param jit [RubyVM::MJIT::JITState]
+    # @param ctx [RubyVM::MJIT::Context]
+    # @param asm [RubyVM::MJIT::Assembler]
+    def opt_getconstant_path(jit, ctx, asm)
+      ic = C.iseq_inline_constant_cache.new(jit.operand(0))
+      idlist = ic.segments
+
+      # See vm_ic_hit_p(). The same conditions are checked in yjit_constant_ic_update().
+      ice = ic.entry
+      if ice.nil?
+        # In this case, leave a block that unconditionally side exits
+        # for the interpreter to invalidate.
+        return CantCompile
+      end
+
+      # Make sure there is an exit for this block as the interpreter might want
+      # to invalidate this block from yjit_constant_ic_update().
+      Invariants.ensure_block_entry_exit(jit, cause: 'opt_getconstant_path')
+
+      if ice.ic_cref # with cref
+        # Not supported yet
+        return CantCompile
+      else # without cref
+        # TODO: implement this
+        # Optimize for single ractor mode.
+        # if !assume_single_ractor_mode(jit, ocb)
+        #   return CantCompile
+        # end
+
+        # Invalidate output code on any constant writes associated with
+        # constants referenced within the current block.
+        #assume_stable_constant_names(jit, ocb, idlist);
+
+        putobject(jit, ctx, asm, val: ice.value)
+      end
+
+      jump_to_next_insn(jit, ctx, asm)
+      EndBlock
+    end
+
     # getconstant
     # setconstant
     # getglobal

lib/ruby_vm/mjit/invariants.rb

@@ -24,14 +24,14 @@ module RubyVM::MJIT
       def assume_bop_not_redefined(jit, klass, op)
         return false unless C.BASIC_OP_UNREDEFINED_P(klass, op)
 
-        ensure_block_entry_exit(jit.block, cause: 'assume_bop_not_redefined')
+        ensure_block_entry_exit(jit, cause: 'assume_bop_not_redefined')
         @bop_blocks << jit.block
         true
       end
 
       # @param jit [RubyVM::MJIT::JITState]
       def assume_method_lookup_stable(jit, cme)
-        ensure_block_entry_exit(jit.block, cause: 'assume_method_lookup_stable')
+        ensure_block_entry_exit(jit, cause: 'assume_method_lookup_stable')
         @cme_blocks[cme.to_i] << jit.block
       end
 
@@ -80,10 +80,10 @@ module RubyVM::MJIT
         end
       end
 
-      private
-
+      # @param jit [RubyVM::MJIT::JITState]
       # @param block [RubyVM::MJIT::Block]
-      def ensure_block_entry_exit(block, cause:)
+      def ensure_block_entry_exit(jit, cause:)
+        block = jit.block
         if block.entry_exit.nil?
           block.entry_exit = Assembler.new.then do |asm|
             @exit_compiler.compile_entry_exit(block.pc, block.ctx, asm, cause:)