Implement opt_minus

lib/ruby_vm/mjit/assembler.rb

@@ -163,6 +163,17 @@ module RubyVM::MJIT
       end
     end
 
+    def jo(dst)
+      case dst
+      # JO rel32
+      in Integer => dst_addr
+        # 0F 80 cd
+        insn(opcode: [0x0f, 0x80], imm: rel32(dst_addr))
+      else
+        raise NotImplementedError, "jo: not-implemented operands: #{dst.inspect}"
+      end
+    end
+
     def jz(dst)
       case dst
       # JZ rel8
@@ -333,12 +344,28 @@ module RubyVM::MJIT
       end
     end
 
-    # RET
     def ret
+      # RET
       # Near return: A return to a procedure within the current code segment
       insn(opcode: 0xc3)
     end
 
+    def sub(dst, src)
+      case [dst, src]
+      # SUB r/m64, r64 (Mod 11: reg)
+      in [Symbol => dst_reg, Symbol => src_reg] if r64?(dst_reg) && r64?(src_reg)
+        # REX.W + 29 /r
+        # MR: Operand 1: ModRM:r/m (r, w), Operand 2: ModRM:reg (r)
+        insn(
+          prefix: REX_W,
+          opcode: 0x29,
+          mod_rm: ModRM[mod: Mod11, reg: src_reg, rm: dst_reg],
+        )
+      else
+        raise NotImplementedError, "sub: not-implemented operands: #{dst.inspect}, #{src.inspect}"
+      end
+    end
+
     def test(left, right)
       case [left, right]
       # TEST r/m8*, imm8 (Mod 01: [reg]+disp8)

lib/ruby_vm/mjit/insn_compiler.rb

@@ -17,7 +17,7 @@ module RubyVM::MJIT
       asm.incr_counter(:mjit_insns_count)
       asm.comment("Insn: #{insn.name}")
 
-      # 9/101
+      # 10/101
       case insn.name
       # nop
       # getlocal
@@ -88,7 +88,7 @@ module RubyVM::MJIT
       # once
       # opt_case_dispatch
       # opt_plus
-      # opt_minus
+      when :opt_minus then opt_minus(jit, ctx, asm)
       # opt_mult
       # opt_div
       # opt_mod
@@ -316,7 +316,50 @@ module RubyVM::MJIT
     # once
     # opt_case_dispatch
     # opt_plus
-    # opt_minus
+
+    # @param jit [RubyVM::MJIT::JITState]
+    # @param ctx [RubyVM::MJIT::Context]
+    # @param asm [RubyVM::MJIT::Assembler]
+    def opt_minus(jit, ctx, asm)
+      unless jit.at_current_insn?
+        defer_compilation(jit, ctx, asm)
+        return EndBlock
+      end
+
+      comptime_recv = jit.peek_at_stack(1)
+      comptime_obj  = jit.peek_at_stack(0)
+
+      if fixnum?(comptime_recv) && fixnum?(comptime_obj)
+        unless @invariants.assume_bop_not_redefined(jit, C.INTEGER_REDEFINED_OP_FLAG, C.BOP_MINUS)
+          return CantCompile
+        end
+
+        raise 'sp_offset != stack_size' if ctx.sp_offset != ctx.stack_size # TODO: handle this
+        recv_index = ctx.stack_size - 2
+        obj_index  = ctx.stack_size - 1
+
+        asm.comment('guard recv is fixnum') # TODO: skip this with type information
+        asm.test([SP, C.VALUE.size * recv_index], C.RUBY_FIXNUM_FLAG)
+        asm.jz(side_exit(jit, ctx))
+
+        asm.comment('guard obj is fixnum') # TODO: skip this with type information
+        asm.test([SP, C.VALUE.size * obj_index], C.RUBY_FIXNUM_FLAG)
+        asm.jz(side_exit(jit, ctx))
+
+        asm.mov(:rax, [SP, C.VALUE.size * recv_index])
+        asm.mov(:rcx, [SP, C.VALUE.size * obj_index])
+        asm.sub(:rax, :rcx)
+        asm.jo(side_exit(jit, ctx))
+        asm.add(:rax, 1)
+        asm.mov([SP, C.VALUE.size * recv_index], :rax)
+
+        ctx.stack_pop(1)
+        KeepCompiling
+      else
+        CantCompile # TODO: delegate to send
+      end
+    end
+
     # opt_mult
     # opt_div
     # opt_mod
@@ -346,11 +389,11 @@ module RubyVM::MJIT
 
         asm.comment('guard recv is fixnum') # TODO: skip this with type information
         asm.test([SP, C.VALUE.size * recv_index], C.RUBY_FIXNUM_FLAG)
-        asm.je(side_exit(jit, ctx))
+        asm.jz(side_exit(jit, ctx))
 
         asm.comment('guard obj is fixnum') # TODO: skip this with type information
         asm.test([SP, C.VALUE.size * obj_index], C.RUBY_FIXNUM_FLAG)
-        asm.je(side_exit(jit, ctx))
+        asm.jz(side_exit(jit, ctx))
 
         asm.mov(:rax, [SP, C.VALUE.size * obj_index])
         asm.cmp([SP, C.VALUE.size * recv_index], :rax)

mjit_c.rb

@@ -261,6 +261,10 @@ module RubyVM::MJIT # :nodoc: all
     Primitive.cexpr! %q{ UINT2NUM(BOP_LT) }
   end
 
+  def C.BOP_MINUS
+    Primitive.cexpr! %q{ UINT2NUM(BOP_MINUS) }
+  end
+
   def C.INTEGER_REDEFINED_OP_FLAG
     Primitive.cexpr! %q{ UINT2NUM(INTEGER_REDEFINED_OP_FLAG) }
   end

tool/mjit/bindgen.rb

@@ -354,6 +354,7 @@ generator = BindingGenerator.new(
     ],
     UINT: %w[
       BOP_LT
+      BOP_MINUS
       INTEGER_REDEFINED_OP_FLAG
       RUBY_EVENT_CLASS
       SHAPE_CAPACITY_CHANGE