1 files changed, 65 insertions, 0 deletions
diff --git a/lib/ruby_vm/rjit/jit_state.rb b/lib/ruby_vm/rjit/jit_state.rb
new file mode 100644
index 0000000000..02a713474e
--- /dev/null
+++ b/lib/ruby_vm/rjit/jit_state.rb
@@ -0,0 +1,65 @@
+module RubyVM::RJIT
+  class JITState < Struct.new(
+    :iseq,                        # @param `RubyVM::RJIT::CPointer::Struct_rb_iseq_t`
+    :pc,                          # @param [Integer] The JIT target PC
+    :cfp,                         # @param `RubyVM::RJIT::CPointer::Struct_rb_control_frame_t` The JIT source CFP (before RJIT is called)
+    :block,                       # @param [RubyVM::RJIT::Block]
+    :stack_size_for_pc,           # @param [Integer]
+    :side_exit_for_pc,            # @param [Hash{ Integer => Integer }] { sp_offset => address }
+    :record_boundary_patch_point, # @param [TrueClass,FalseClass]
+  )
+    def initialize(side_exit_for_pc: {}, record_boundary_patch_point: false, **) = super
+
+    def insn
+      Compiler.decode_insn(C.VALUE.new(pc).*)
+    end
+
+    def operand(index, signed: false, ruby: false)
+      addr = pc + (index + 1) * Fiddle::SIZEOF_VOIDP
+      value = Fiddle::Pointer.new(addr)[0, Fiddle::SIZEOF_VOIDP].unpack(signed ? 'q' : 'Q')[0]
+      if ruby
+        value = C.to_ruby(value)
+      end
+      value
+    end
+
+    def at_current_insn?
+      pc == cfp.pc.to_i
+    end
+
+    def peek_at_local(n)
+      local_table_size = iseq.body.local_table_size
+      offset = -C::VM_ENV_DATA_SIZE - local_table_size + n + 1
+      value = (cfp.ep + offset).*
+      C.to_ruby(value)
+    end
+
+    def peek_at_stack(depth_from_top)
+      raise 'not at current insn' unless at_current_insn?
+      offset = -(1 + depth_from_top)
+      # rb_rjit_branch_stub_hit updates SP, so you don't need to worry about sp_offset
+      value = (cfp.sp + offset).*
+      C.to_ruby(value)
+    end
+
+    def peek_at_self
+      C.to_ruby(cfp.self)
+    end
+
+    def peek_at_block_handler(level)
+      ep = ep_at_level(cfp, level:)
+      ep[C::VM_ENV_DATA_INDEX_SPECVAL]
+    end
+
+    private
+
+    def ep_at_level(cfp, level:)
+      ep = cfp.ep
+      level.times do
+        # VM_ENV_PREV_EP
+        ep = C.VALUE.new(ep[C::VM_ENV_DATA_INDEX_SPECVAL] & ~0x03)
+      end
+      ep
+    end
+  end
+end