From b182f2a04520a0138992b27f9e6bfd15bdfd6f96 Mon Sep 17 00:00:00 2001
From: Koichi Sasada <ko1@atdot.net>
Date: Thu, 20 Jun 2024 23:56:03 +0900
Subject: [PATCH] fix sendfwd with `send` and `method_missing`

combination with `send` method (optimized) or `method_missing`
and forwarding send (`...`) needs to respect given
`rb_forwarding_call_data`. Otherwize it causes critical error
such as SEGV.
---
 bootstraptest/test_method.rb | 38 ++++++++++++++++++++++---------
 vm_insnhelper.c              | 43 +++++++++++++++++++++++++++++++-----
 2 files changed, 65 insertions(+), 16 deletions(-)

diff --git a/bootstraptest/test_method.rb b/bootstraptest/test_method.rb
index 3929d69da4..846d8e36a9 100644
--- a/bootstraptest/test_method.rb
+++ b/bootstraptest/test_method.rb
@@ -1315,14 +1315,32 @@ assert_equal 'ok', %q{
 }
 
 assert_equal 'ok', %q{
-def foo(a, b) = a + b
-def bar(...) = foo(...)
-bar(1, 2)
-bar(1, 2)
-begin
-  bar(1, 2, 3)
-  "ng"
-rescue ArgumentError
-  "ok"
-end
+  def foo(a, b) = a + b
+  def bar(...) = foo(...)
+  bar(1, 2)
+  bar(1, 2)
+  begin
+    bar(1, 2, 3)
+    "ng"
+  rescue ArgumentError
+    "ok"
+  end
+}
+
+assert_equal 'ok', %q{
+  class C
+    def foo(...) = :ok
+    def bar(...) = __send__(:foo, ...)
+  end
+
+  C.new.bar
+}
+
+assert_equal 'ok', %q{
+  class C
+    def method_missing(...) = :ok
+    def foo(...) = xyzzy(...)
+  end
+
+  C.new.foo
 }
diff --git a/vm_insnhelper.c b/vm_insnhelper.c
index 33d39ab857..be43e737fe 100644
--- a/vm_insnhelper.c
+++ b/vm_insnhelper.c
@@ -3069,6 +3069,9 @@ vm_callee_setup_arg(rb_execution_context_t *ec, struct rb_calling_info *calling,
     const struct rb_callinfo *ci = calling->cd->ci;
     const struct rb_callcache *cc = calling->cc;
 
+    VM_ASSERT((vm_ci_argc(ci), 1));
+    VM_ASSERT(vm_cc_cme(cc) != NULL);
+
     if (UNLIKELY(!ISEQ_BODY(iseq)->param.flags.use_block &&
                  calling->block_handler != VM_BLOCK_HANDLER_NONE &&
                  !(vm_ci_flag(calling->cd->ci) & VM_CALL_SUPER))) {
@@ -4235,10 +4238,23 @@ vm_call_symbol(rb_execution_context_t *ec, rb_control_frame_t *reg_cfp,
         }
     }
 
-    calling->cd = &(struct rb_call_data) {
-        .ci = &VM_CI_ON_STACK(mid, flags, argc, vm_ci_kwarg(ci)),
-        .cc = NULL,
+    struct rb_forwarding_call_data new_fcd = {
+        .cd = {
+            .ci = &VM_CI_ON_STACK(mid, flags, argc, vm_ci_kwarg(ci)),
+            .cc = NULL,
+        },
+        .caller_ci = NULL,
     };
+
+    if (!(vm_ci_flag(ci) & VM_CALL_FORWARDING)) {
+        calling->cd = &new_fcd.cd;
+    }
+    else {
+        const struct rb_callinfo *caller_ci = ((struct rb_forwarding_call_data *)calling->cd)->caller_ci;
+        VM_ASSERT((vm_ci_argc(caller_ci), 1));
+        new_fcd.caller_ci = caller_ci;
+        calling->cd = (struct rb_call_data *)&new_fcd;
+    }
     calling->cc = &VM_CC_ON_STACK(klass,
                                   vm_call_general,
                                   { .method_missing_reason = missing_reason },
@@ -4381,10 +4397,25 @@ vm_call_method_missing_body(rb_execution_context_t *ec, rb_control_frame_t *reg_
     INC_SP(1);
 
     ec->method_missing_reason = reason;
-    calling->cd = &(struct rb_call_data) {
-        .ci = &VM_CI_ON_STACK(idMethodMissing, flag, argc, vm_ci_kwarg(orig_ci)),
-        .cc = NULL,
+
+    struct rb_forwarding_call_data new_fcd = {
+        .cd = {
+            .ci = &VM_CI_ON_STACK(idMethodMissing, flag, argc, vm_ci_kwarg(orig_ci)),
+            .cc = NULL,
+        },
+        .caller_ci = NULL,
     };
+
+    if (!(flag & VM_CALL_FORWARDING)) {
+        calling->cd = &new_fcd.cd;
+    }
+    else {
+        const struct rb_callinfo *caller_ci = ((struct rb_forwarding_call_data *)calling->cd)->caller_ci;
+        VM_ASSERT((vm_ci_argc(caller_ci), 1));
+        new_fcd.caller_ci = caller_ci;
+        calling->cd = (struct rb_call_data *)&new_fcd;
+    }
+
     calling->cc = &VM_CC_ON_STACK(Qundef, vm_call_general, {{ 0 }},
                                   rb_callable_method_entry_without_refinements(CLASS_OF(calling->recv), idMethodMissing, NULL));
     return vm_call_method(ec, reg_cfp, calling);