From 0a82bfe5e18ac86da72c27389db6eb8da156a0b5 Mon Sep 17 00:00:00 2001
From: Koichi Sasada <ko1@atdot.net>
Date: Thu, 2 Feb 2023 09:13:19 +0900
Subject: [PATCH] use correct svar (#7225)

* use correct svar

Without this patch, svar location is used "nearest Ruby frame".
It is almost correct but it doesn't correct when the `each` method
is written in Ruby.

```ruby
class C
  include Enumerable
  def each
    %w(bar baz).each{|e| yield e}
  end
end

C.new.grep(/(b.)/){|e| p [$1, e]}
```

This patch fix this issue by traversing ifunc's cfp.

Note that if cfp doesn't specify this Thread's cfp stack, reserved
svar location (`ec->root_svar`) is used.

* make yjit-bindgen

---------

Co-authored-by: Takashi Kokubun <takashikkbn@gmail.com>
---
 internal/imemo.h               |  2 +-
 proc.c                         |  2 +-
 vm.c                           | 23 ++++++++++++++++++-----
 yjit/src/cruby_bindings.inc.rs |  2 +-
 4 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/internal/imemo.h b/internal/imemo.h
index ef07333a58..8d506dda7d 100644
--- a/internal/imemo.h
+++ b/internal/imemo.h
@@ -82,7 +82,7 @@ struct vm_ifunc_argc {
 /*! IFUNC (Internal FUNCtion) */
 struct vm_ifunc {
     VALUE flags;
-    VALUE reserved;
+    struct rb_control_frame_struct *owner_cfp;
     rb_block_call_func_t func;
     const void *data;
     struct vm_ifunc_argc argc;
diff --git a/proc.c b/proc.c
index c31017128e..b4f602a4cb 100644
--- a/proc.c
+++ b/proc.c
@@ -752,7 +752,7 @@ rb_vm_ifunc_new(rb_block_call_func_t func, const void *data, int min_argc, int m
     }
     arity.argc.min = min_argc;
     arity.argc.max = max_argc;
-    VALUE ret = rb_imemo_new(imemo_ifunc, (VALUE)func, (VALUE)data, arity.packed, 0);
+    VALUE ret = rb_imemo_new(imemo_ifunc, (VALUE)func, (VALUE)data, arity.packed, (VALUE)GET_EC()->cfp);
     return (struct vm_ifunc *)ret;
 }
 
diff --git a/vm.c b/vm.c
index d009a5f64a..bca0992155 100644
--- a/vm.c
+++ b/vm.c
@@ -1621,12 +1621,25 @@ rb_vm_invoke_proc_with_self(rb_execution_context_t *ec, rb_proc_t *proc, VALUE s
 /* special variable */
 
 static rb_control_frame_t *
-vm_normal_frame(const rb_execution_context_t *ec, rb_control_frame_t *cfp)
+vm_svar_frame(const rb_execution_context_t *ec, rb_control_frame_t *cfp)
 {
     while (cfp->pc == 0) {
-        cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(cfp);
+        if (VM_FRAME_TYPE(cfp) ==  VM_FRAME_MAGIC_IFUNC) {
+            struct vm_ifunc *ifunc = (struct vm_ifunc *)cfp->iseq;
+            rb_control_frame_t *owner_cfp = ifunc->owner_cfp;
+            if (cfp < owner_cfp) {
+                cfp = ifunc->owner_cfp;
+            }
+            else {
+                return NULL;
+            }
+        }
+        else {
+            cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(cfp);
+        }
+
         if (RUBY_VM_CONTROL_FRAME_STACK_OVERFLOW_P(ec, cfp)) {
-            return 0;
+            return NULL;
         }
     }
     return cfp;
@@ -1635,14 +1648,14 @@ vm_normal_frame(const rb_execution_context_t *ec, rb_control_frame_t *cfp)
 static VALUE
 vm_cfp_svar_get(const rb_execution_context_t *ec, rb_control_frame_t *cfp, VALUE key)
 {
-    cfp = vm_normal_frame(ec, cfp);
+    cfp = vm_svar_frame(ec, cfp);
     return lep_svar_get(ec, cfp ? VM_CF_LEP(cfp) : 0, key);
 }
 
 static void
 vm_cfp_svar_set(const rb_execution_context_t *ec, rb_control_frame_t *cfp, VALUE key, const VALUE val)
 {
-    cfp = vm_normal_frame(ec, cfp);
+    cfp = vm_svar_frame(ec, cfp);
     lep_svar_set(ec, cfp ? VM_CF_LEP(cfp) : 0, key, val);
 }
 
diff --git a/yjit/src/cruby_bindings.inc.rs b/yjit/src/cruby_bindings.inc.rs
index ea57ea67fd..128b249e3b 100644
--- a/yjit/src/cruby_bindings.inc.rs
+++ b/yjit/src/cruby_bindings.inc.rs
@@ -570,7 +570,7 @@ pub struct vm_ifunc_argc {
 #[repr(C)]
 pub struct vm_ifunc {
     pub flags: VALUE,
-    pub reserved: VALUE,
+    pub owner_cfp: *mut rb_control_frame_struct,
     pub func: rb_block_call_func_t,
     pub data: *const ::std::os::raw::c_void,
     pub argc: vm_ifunc_argc,