Add storage for special variables and primitive to access them.

Author: aardvark179

lib/truffle/stringio.rb

@@ -315,7 +315,7 @@ def gets(sep=$/, limit=Undefined)
 
     # Truffle: $_ is thread and frame local, so we use a primitive to
     # set it in the caller's frame.
-    Primitive.frame_local_variable_set(:$_, getline(false, sep, limit), Primitive.caller_binding)
+    Primitive.io_last_line_set(Primitive.caller_special_variable, getline(false, sep, limit))
   end
 
   def isatty
@@ -346,7 +346,7 @@ def pos=(pos)
 
   def print(*args)
     check_writable
-    args << Primitive.frame_local_variable_get(:$_, Primitive.caller_binding) if args.empty?
+    args << Primitive.io_last_line_get(Primitive.caller_special_variable) if args.empty?
     write((args << $\).flatten.join)
     nil
   end
@@ -449,7 +449,7 @@ def readline(sep=$/, limit=Undefined)
     check_readable
     raise EOFError, 'end of file reached' if eof?
 
-    Primitive.frame_local_variable_set(:$_, getline(true, sep, limit), Primitive.caller_binding)
+    Primitive.io_last_line_set(Primitive.caller_special_variable, getline(true, sep, limit))
   end
 
   def readlines(sep=$/, limit=Undefined)

lib/truffle/truffle/cext.rb

@@ -1700,8 +1700,7 @@ def rb_tr_writable(mode)
   end
 
   def rb_backref_get
-    Primitive.frame_local_variable_get(:$~,
-      Truffle::ThreadOperations.ruby_caller([Truffle::CExt, Truffle::Interop.singleton_class]))
+    Primitive.regexp_last_match_get(Truffle::ThreadOperations.ruby_caller_special_variable([Truffle::CExt, Truffle::Interop.singleton_class]))
   end
 
   def rb_gv_set(name, value)
@@ -1719,7 +1718,7 @@ def rb_gv_get(name)
 
   def rb_reg_match(re, str)
     result = str ? Truffle::RegexpOperations.match(re, str, 0) : nil
-    Primitive.frame_local_variable_set(:$~, result, Truffle::ThreadOperations.ruby_caller([Truffle::CExt, Truffle::Interop.singleton_class]))
+    Primitive.regexp_last_match_set(Truffle::ThreadOperations.ruby_caller_special_variable([Truffle::CExt, Truffle::Interop.singleton_class]), result)
 
     result.begin(0) if result
   end

src/main/java/org/truffleruby/Layouts.java

@@ -11,6 +11,8 @@
 
 import com.oracle.truffle.api.object.HiddenKey;
 
+import org.truffleruby.parser.TranslatorEnvironment;
+
 public abstract class Layouts {
 
     // Standard identifiers
@@ -23,4 +25,8 @@ public abstract class Layouts {
     public static final HiddenKey MARKED_OBJECTS_IDENTIFIER = new HiddenKey("marked_objects"); // Object[]
     public static final HiddenKey VALUE_WRAPPER_IDENTIFIER = new HiddenKey("value_wrapper"); // ValueWrapper
 
+    // Frame slot name for special variable storage.
+
+    public static final String SPECIAL_VARIABLLE_STORAGE = TranslatorEnvironment.TEMP_PREFIX + "$~_";
+
 }

src/main/java/org/truffleruby/RubyContext.java

@@ -424,7 +424,7 @@ public Object send(Object object, String methodName, Object... arguments) {
 
         return IndirectCallNode.getUncached().call(
                 method.getCallTarget(),
-                RubyArguments.pack(null, null, method, null, object, null, arguments));
+                RubyArguments.pack(null, null, null, method, null, object, null, arguments));
     }
 
     @TruffleBoundary

src/main/java/org/truffleruby/core/CoreLibrary.java

@@ -25,6 +25,7 @@
 
 import org.jcodings.specific.USASCIIEncoding;
 import org.jcodings.transcode.EConvFlags;
+import org.truffleruby.Layouts;
 import org.truffleruby.RubyContext;
 import org.truffleruby.RubyLanguage;
 import org.truffleruby.SuppressFBWarnings;
@@ -77,6 +78,7 @@
 import com.oracle.truffle.api.Truffle;
 import com.oracle.truffle.api.TruffleOptions;
 import com.oracle.truffle.api.frame.FrameDescriptor;
+import com.oracle.truffle.api.frame.FrameSlot;
 import com.oracle.truffle.api.object.DynamicObjectLibrary;
 import com.oracle.truffle.api.source.Source;
 import com.oracle.truffle.api.source.SourceSection;
@@ -224,6 +226,11 @@ public class CoreLibrary {
     public final GlobalVariables globalVariables;
 
     public final FrameDescriptor emptyDescriptor;
+    /* Some things (such as procs created from symbols) require a declaration frame, and this should include a slot for
+     * special variable storage. This frame descriptor should be used for those frames to provide a constant frame shape
+     * in those cases. */
+    public final FrameDescriptor emptyDeclarationDescriptor;
+    public final FrameSlot emptyDeclarationSpecialVariableSlot;
 
     @CompilationFinal private RubyClass eagainWaitReadable;
     @CompilationFinal private RubyClass eagainWaitWritable;
@@ -585,6 +592,9 @@ public CoreLibrary(RubyContext context) {
 
         mainObject = new RubyBasicObject(objectClass, language.basicObjectShape);
         emptyDescriptor = new FrameDescriptor(Nil.INSTANCE);
+        emptyDeclarationDescriptor = new FrameDescriptor(Nil.INSTANCE);
+        emptyDeclarationSpecialVariableSlot = emptyDeclarationDescriptor
+                .addFrameSlot(Layouts.SPECIAL_VARIABLLE_STORAGE);
         argv = new RubyArray(arrayClass, RubyLanguage.arrayShape, ArrayStoreLibrary.INITIAL_STORE, 0);
 
         globalVariables = new GlobalVariables();

src/main/java/org/truffleruby/core/binding/BindingNodes.java

@@ -106,6 +106,7 @@ public static MaterializedFrame newFrame(MaterializedFrame parent, FrameDescript
                 RubyArguments.pack(
                         parent,
                         null,
+                        null,
                         RubyArguments.getMethod(parent),
                         RubyArguments.getDeclarationContext(parent),
                         null,

src/main/java/org/truffleruby/core/kernel/KernelNodes.java

@@ -786,6 +786,7 @@ private Object eval(Object target, RootNodeWrapper rootNode, RootCallTarget call
             return callNode.call(RubyArguments.pack(
                     parentFrame,
                     null,
+                    null,
                     method,
                     null,
                     target,