monkeypatch load_iseq for debugger to work along with bootsnap (#61)

* monkey patch InstructionSequence#load_iseq to set tracing flags

* workaround for ruby versions older than 2.5.0

Author: viuginick1

ext/attach/extconf.rb

@@ -28,7 +28,13 @@
 require "debase/ruby_core_source"
 
 hdrs = proc {
-  have_header("vm_core.h")
+  have_header("vm_core.h") and
+  have_header("iseq.h") and
+  have_header("version.h") and
+  have_header("vm_core.h") and
+  have_header("vm_insnhelper.h") and
+  have_header("vm_core.h") and
+  have_header("method.h")
 }
 
 # Allow use customization of compile options. For example, the

ext/debase_internals.c

@@ -637,6 +637,36 @@ Debase_enable_file_filtering(VALUE self, VALUE value)
   return value;
 }
 
+#if RUBY_API_VERSION_CODE >= 20500
+    static const rb_iseq_t *
+    my_iseqw_check(VALUE iseqw)
+    {
+        rb_iseq_t *iseq = DATA_PTR(iseqw);
+
+        if (!iseq->body) {
+            ibf_load_iseq_complete(iseq);
+        }
+
+        if (!iseq->body->location.label) {
+            rb_raise(rb_eTypeError, "uninitialized InstructionSequence");
+        }
+        return iseq;
+    }
+
+    static void
+    Debase_set_trace_flag_to_iseq(VALUE self, VALUE rb_iseq)
+    {
+        if (!SPECIAL_CONST_P(rb_iseq) && RBASIC_CLASS(rb_iseq) == rb_cISeq) {
+            rb_iseq_t *iseq = my_iseqw_check(rb_iseq);
+            rb_iseq_trace_set(iseq, RUBY_EVENT_TRACEPOINT_ALL);
+        }
+    }
+#else
+      static void
+      Debase_set_trace_flag_to_iseq(VALUE self, VALUE rb_iseq) {
+      }
+#endif
+
 static VALUE
 Debase_init_variables()
 {
@@ -680,6 +710,7 @@ Init_debase_internals()
   rb_define_module_function(mDebase, "enable_trace_points", Debase_enable_trace_points, 0);
   rb_define_module_function(mDebase, "prepare_context", Debase_prepare_context, 0);
   rb_define_module_function(mDebase, "init_variables", Debase_init_variables, 0);
+  rb_define_module_function(mDebase, "set_trace_flag_to_iseq", Debase_set_trace_flag_to_iseq, 1);
 
   idAlive = rb_intern("alive?");
   idAtLine = rb_intern("at_line");

ext/debase_internals.h

@@ -1,7 +1,12 @@
 #ifndef DEBASE_INTERNALS
 #define DEBASE_INTERNALS
 
-#include <ruby.h>
+#include "ruby.h"
+#include "vm_core.h"
+#include "version.h"
+#include "iseq.h"
+#include "vm_insnhelper.h"
+#include "method.h"
 #include <ruby/debug.h>
 
 typedef struct rb_trace_arg_struct rb_trace_point_t;

ext/extconf.rb

@@ -28,8 +28,13 @@
 require "debase/ruby_core_source"
 
 hdrs = proc {
-  have_header("vm_core.h")
-  have_header("version.h")
+  have_header("vm_core.h") and
+  have_header("iseq.h") and
+  have_header("version.h") and
+  have_header("vm_core.h") and
+  have_header("vm_insnhelper.h") and
+  have_header("vm_core.h") and
+  have_header("method.h")
 }
 
 # Allow use customization of compile options. For example, the

lib/debase.rb

@@ -20,7 +20,21 @@ def start(options={}, &block)
       Debugger.const_set('ARGV', ARGV.clone) unless defined? Debugger::ARGV
       Debugger.const_set('PROG_SCRIPT', $0) unless defined? Debugger::PROG_SCRIPT
       Debugger.const_set('INITIAL_DIR', Dir.pwd) unless  defined? Debugger::INITIAL_DIR
-      return Debugger.started? ? block && block.call(self) : Debugger.start_(&block) 
+
+      monkey_patch_prepend
+
+      Debugger.started? ? block && block.call(self) : Debugger.start_(&block)
+    end
+
+    def monkey_patch_prepend
+      class << RubyVM::InstructionSequence
+        def self.prepend(mod, *smth)
+          super
+          if mod.to_s.include? 'Bootsnap'
+            prepend InstructionSequenceMixin
+          end
+        end
+      end
     end
 
     # @param [String] file
@@ -81,6 +95,21 @@ def last_context
     def file_filter
       @file_filter ||= FileFilter.new
     end
+
+    module InstructionSequenceMixin
+      def load_iseq(path)
+        iseq = super(path)
+
+        do_set_flags(iseq)
+
+        iseq
+      end
+
+      def do_set_flags(iseq)
+        Debugger.set_trace_flag_to_iseq(iseq)
+        iseq.each_child{|child_iseq| do_set_flags(child_iseq)}
+      end
+    end
   end
 
   class FileFilter

lib/debase/version.rb

@@ -1,3 +1,3 @@
 module Debase
-  VERSION = "0.2.3.beta1" unless defined? VERSION
+  VERSION = "0.2.3.beta2" unless defined? VERSION
 end