_mjit_compile_getivar.erb: optimize IC-hit getivar

by inlining index (and serial to invalidate that) and simplifying the
branch by using JIT cancellation.

mjit_compile.inc.erb: use the above file
mjit_compile.c: copy USE_IC_FOR_IVAR definition. will move this to
another shared file later.
common.mk: add new dependency
test/ruby/test_jit.rb: cover this case

=== Optcarrot benchmark ===
```
$ benchmark-driver benchmark.yml --rbenv '2.0.0::2.0.0-p648;before::before --disable-gems;before+JIT::before --disable-gems --jit;after::after --disable-gems;after+JIT::after --disable-gems --jit' -v --repeat-count 24
2.0.0: ruby 2.0.0p648 (2015-12-16 revision 53162) [x86_64-linux]
before: ruby 2.6.0dev (2018-10-14 trunk 65072) [x86_64-linux]
before+JIT: ruby 2.6.0dev (2018-10-14 trunk 65072) +JIT [x86_64-linux]
after: ruby 2.6.0dev (2018-10-14 trunk 65072) [x86_64-linux]
last_commit=_mjit_compile_getivar.erb: optimize IC-hit getivar
after+JIT: ruby 2.6.0dev (2018-10-14 trunk 65072) +JIT [x86_64-linux]
last_commit=_mjit_compile_getivar.erb: optimize IC-hit getivar
Calculating -------------------------------------
                              2.0.0      before  before+JIT       after   after+JIT
Optcarrot Lan_Master.nes     36.065      53.896      71.565      53.856      84.747 fps

Comparison:
             Optcarrot Lan_Master.nes
               after+JIT:        84.7 fps
              before+JIT:        71.6 fps - 1.18x  slower
                  before:        53.9 fps - 1.57x  slower
                   after:        53.9 fps - 1.57x  slower
                   2.0.0:        36.1 fps - 2.35x  slower

```

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65073 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

5 files changed, 71 insertions, 1 deletions

diff --git a/common.mk b/common.mk
index 41bb45cacb..e6f8c4a843 100644
--- a/common.mk
+++ b/common.mk
@@ -938,7 +938,7 @@ $(srcs_vpath)vm.inc: $(srcdir)/tool/ruby_vm/views/vm.inc.erb $(inc_common_header
   $(srcdir)/tool/ruby_vm/views/_insn_entry.erb $(srcdir)/tool/ruby_vm/views/_trace_instruction.erb
 $(srcs_vpath)mjit_compile.inc: $(srcdir)/tool/ruby_vm/views/mjit_compile.inc.erb $(inc_common_headers) \
   $(srcdir)/tool/ruby_vm/views/_mjit_compile_insn.erb $(srcdir)/tool/ruby_vm/views/_mjit_compile_send.erb \
-  $(srcdir)/tool/ruby_vm/views/_mjit_compile_send_guard.erb \
+  $(srcdir)/tool/ruby_vm/views/_mjit_compile_send_guard.erb $(srcdir)/tool/ruby_vm/views/_mjit_compile_getivar.erb \
   $(srcdir)/tool/ruby_vm/views/_mjit_compile_insn_body.erb $(srcdir)/tool/ruby_vm/views/_mjit_compile_pc_and_sp.erb
 
 common-srcs: $(srcs_vpath)parse.c $(srcs_vpath)lex.c $(srcs_vpath)enc/trans/newline.c $(srcs_vpath)id.c \
diff --git a/mjit_compile.c b/mjit_compile.c
index b2ece0eb77..89d1a96a10 100644
--- a/mjit_compile.c
+++ b/mjit_compile.c
@@ -108,6 +108,11 @@ comment_id(FILE *f, ID id)
 #endif
 }
 
+/* TODO: share this with vm_insnhelper.c */
+#ifndef USE_IC_FOR_IVAR
+#define USE_IC_FOR_IVAR 1
+#endif
+
 static void compile_insns(FILE *f, const struct rb_iseq_constant_body *body, unsigned int stack_size,
                           unsigned int pos, struct compile_status *status);
 
diff --git a/test/ruby/test_jit.rb b/test/ruby/test_jit.rb
index 43e6d80573..3b18373212 100644
--- a/test/ruby/test_jit.rb
+++ b/test/ruby/test_jit.rb
@@ -113,6 +113,25 @@ class TestJIT < Test::Unit::TestCase
       @foo = 1
       @foo
     end;
+
+    # optimized getinstancevariable call
+    assert_eval_with_jit("#{<<~"begin;"}\n#{<<~"end;"}", stdout: '33', success_count: 1, min_calls: 2)
+    begin;
+      class A
+        def initialize
+          @a = 1
+          @b = 2
+        end
+
+        def three
+          @a + @b
+        end
+      end
+
+      a = A.new
+      print(a.three) # set ic
+      print(a.three) # inlined ic
+    end;
   end
 
   def test_compile_insn_classvariable
diff --git a/tool/ruby_vm/views/_mjit_compile_getivar.erb b/tool/ruby_vm/views/_mjit_compile_getivar.erb
new file mode 100644
index 0000000000..630fd72959
--- /dev/null
+++ b/tool/ruby_vm/views/_mjit_compile_getivar.erb
@@ -0,0 +1,44 @@
+% # -*- mode:c; style:ruby; coding: utf-8; indent-tabs-mode: nil -*-
+% # Copyright (c) 2018 Takashi Kokubun.  All rights reserved.
+% #
+% # This file is a part of  the programming language Ruby.  Permission is hereby
+% # granted, to either  redistribute and/or modify this file,  provided that the
+% # conditions mentioned  in the  file COPYING  are met.   Consult the  file for
+% # details.
+%
+% # Optimized case of get_instancevariable instruction.
+#if USE_IC_FOR_IVAR
+{
+% # compiler: Prepare operands which may be used by `insn.call_attribute`
+% insn.opes.each_with_index do |ope, i|
+    MAYBE_UNUSED(<%= ope.fetch(:decl) %>) = (<%= ope.fetch(:type) %>)operands[<%= i %>];
+% end
+%
+% # compiler: Consider receiver as T_OBJECT if ic->ic_serial is set
+    if (ic->ic_serial) {
+% # JIT: optimize away motion of sp and pc. This path does not call rb_warning() and so it's always leaf and not `handles_sp`.
+% # <%= render 'mjit_compile_pc_and_sp', locals: { insn: insn } -%>
+%
+% # JIT: prepare vm_getivar's arguments and variables
+        fprintf(f, "{\n");
+        fprintf(f, "    VALUE obj = GET_SELF();\n");
+        fprintf(f, "    const rb_serial_t ic_serial = (rb_serial_t)%"PRI_SERIALT_PREFIX"u;\n", ic->ic_serial);
+        fprintf(f, "    const st_index_t index = %lu;\n", ic->ic_value.index);
+%
+% # JIT: cache hit path of vm_getivar, or cancel JIT.
+        fprintf(f, "    if (LIKELY(RB_TYPE_P(obj, T_OBJECT) && ic_serial == RCLASS_SERIAL(RBASIC(obj)->klass) && index < ROBJECT_NUMIV(obj))) {\n");
+        fprintf(f, "        stack[%d] = ROBJECT_IVPTR(obj)[index];\n", b->stack_size);
+        fprintf(f, "    }\n");
+        fprintf(f, "    else {\n");
+        fprintf(f, "        reg_cfp->pc = original_body_iseq + %d;\n", pos);
+        fprintf(f, "        reg_cfp->sp = (VALUE *)reg_cfp->bp + %d;\n", b->stack_size + 1);
+        fprintf(f, "        goto cancel;\n");
+        fprintf(f, "    }\n");
+
+% # compiler: Move JIT compiler's internal stack pointer
+        b->stack_size += <%= insn.call_attribute('sp_inc') %>;
+        fprintf(f, "}\n");
+        break;
+    }
+}
+#endif	/* USE_IC_FOR_IVAR */
diff --git a/tool/ruby_vm/views/mjit_compile.inc.erb b/tool/ruby_vm/views/mjit_compile.inc.erb
index ee29693894..d211c57fdb 100644
--- a/tool/ruby_vm/views/mjit_compile.inc.erb
+++ b/tool/ruby_vm/views/mjit_compile.inc.erb
@@ -52,6 +52,8 @@ switch (insn) {
 <%=   render 'mjit_compile_send', locals: { insn: insn } -%>
 %   when 'opt_aref' # experimental. TODO: increase insns and make the list automatically by finding DISPATCH_ORIGINAL_INSN
 <%=   render 'mjit_compile_send', locals: { insn: opt_send_without_block } -%>
+%   when 'getinstancevariable'
+<%=   render 'mjit_compile_getivar', locals: { insn: insn } -%>
 %   when 'leave'
     if (b->stack_size != 1) {
         if (mjit_opts.warnings || mjit_opts.verbose)