[GR-28775] Implement rb_lastline_set.

PullRequest: truffleruby/2330

Author: eregon

CHANGELOG.md

@@ -43,6 +43,7 @@ Compatibility:
 * Fixed `Integer#digits` implementation to handle more bases (#2224, #2225).
 * Support the `inherit` parameter for `Module#{private, protected, public}_method_defined?`.
 * Implement `Thread.pending_interrupt?` and `Thread#pending_interrupt?` (#2219).
+* Implement `rb_lastline_set` (#2170).
 
 Performance:
 

lib/truffle/truffle/cext.rb

@@ -1840,4 +1840,14 @@ def rb_thread_current_backtrace_locations
   def rb_syserr_new(errno, mesg)
     SystemCallError.new(mesg, errno)
   end
+
+  def rb_lastline_set(str)
+    storage = Primitive.ruby_caller_special_variables
+    Primitive.io_last_line_set(storage, str)
+  end
+
+  def rb_lastline_get
+    storage = Primitive.ruby_caller_special_variables
+    Primitive.io_last_line_get(storage)
+  end
 end

spec/tags/optional/capi/globals_tags.txt

@@ -194,3 +194,12 @@ void rb_io_set_nonblock(rb_io_t *fptr) {
 FILE *rb_io_stdio_file(rb_io_t *fptr) {
   rb_tr_error("rb_io_stdio_file not yet implemented");
 }
+
+VALUE rb_lastline_get(void) {
+  return RUBY_CEXT_INVOKE("rb_lastline_get");
+}
+
+void rb_lastline_set(VALUE str) {
+  RUBY_CEXT_INVOKE_NO_WRAP("rb_lastline_set", str);
+}
+

src/main/c/cext/io.c

@@ -53,13 +53,17 @@
 import com.oracle.truffle.api.dsl.NodeChild;
 import com.oracle.truffle.api.dsl.Specialization;
 import com.oracle.truffle.api.frame.FrameDescriptor;
+import com.oracle.truffle.api.frame.FrameInstance.FrameAccess;
 import com.oracle.truffle.api.frame.FrameSlot;
 import com.oracle.truffle.api.frame.FrameSlotKind;
 import com.oracle.truffle.api.frame.FrameUtil;
 import com.oracle.truffle.api.frame.MaterializedFrame;
 import com.oracle.truffle.api.frame.VirtualFrame;
 import com.oracle.truffle.api.nodes.IndirectCallNode;
+import com.oracle.truffle.api.nodes.Node;
+import com.oracle.truffle.api.nodes.RootNode;
 import com.oracle.truffle.api.profiles.ConditionProfile;
+import com.oracle.truffle.api.Truffle;
 
 @CoreModule("Truffle::KernelOperations")
 public abstract class TruffleKernelNodes {
@@ -323,6 +327,38 @@ protected Object storage(VirtualFrame frame) {
         }
     }
 
+    /* When getting special variables from the wrong side of a C call we know it's going to be slow. */
+    @Primitive(name = "ruby_caller_special_variables")
+    public abstract static class GetSlowCallerSpecialVariableStorage extends PrimitiveArrayArgumentsNode {
+
+        @Child GetSpecialVariableStorage getStorageNode = GetSpecialVariableStorage.create();
+
+        @Specialization
+        @TruffleBoundary
+        protected Object storage() {
+            return getStorageNode.execute(Truffle.getRuntime().iterateFrames(frameInstance -> {
+                final Node callNode = frameInstance.getCallNode();
+
+                if (callNode != null) {
+                    final RootNode rootNode = callNode.getRootNode();
+                    // Skip Ruby frames in cext.rb file since they are implementing methods which are implemented
+                    // with C in MRI, and therefore are also implicitly skipped when when looking up the block passed
+                    // to a C API function.
+                    if (rootNode instanceof RubyRootNode &&
+                            rootNode.getSourceSection().isAvailable() &&
+                            !rootNode.getSourceSection().getSource().getName().endsWith("cext.rb") &&
+                            !rootNode.getSourceSection().getSource().getName().endsWith("cext_ruby.rb") &&
+                            !getContext().getCoreLibrary().isSend(
+                                    RubyArguments.tryGetMethod(frameInstance.getFrame(FrameAccess.READ_ONLY)))) {
+                        return frameInstance.getFrame(FrameAccess.MATERIALIZE).materialize();
+                    }
+                }
+
+                return null;
+            }));
+        }
+    }
+
     @Primitive(name = "proc_special_variables")
     public abstract static class GetProcSpecialVariableStorage extends PrimitiveArrayArgumentsNode {