LiveEdit: patch positions in function

test/mjsunit/debug-liveedit-patch-positions-replace.js

+// Copyright 2010 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
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+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Flags: --expose-debug-as debug
+// Get the Debug object exposed from the debug context global object.
+
+// Scenario: a function is being changed, which causes enclosing function to
+// have its positions patched; position changing requires new instance of Code
+// object to be introduced; the function happens to be on stack at this moment;
+// later it will resume over new instance of Code.
+// Before the change 2 rinfo are 22 characters away from each other. After the
+// change they are 114 characters away from each other. New instance of Code is
+// required when those numbers cross the border value of 64 (in any direction).
+
+Debug = debug.Debug
+
+eval(
+    "function BeingReplaced(changer, opt_x, opt_y) {\n" +
+    "  changer();\n" +
+    "  var res = new Object();\n" +
+    "  if (opt_x) { res.y = opt_y; }\n" +
+    "  res.a = (function() {})();\n" +
+    "  return res.a;\n" +
+    "}"
+);
+
+var script = Debug.findScript(BeingReplaced);
+
+var orig_body = "{}";
+var patch_pos = script.source.indexOf(orig_body);
+// Line long enough to change rinfo encoding.
+var new_body_patch = "{return 'Capybara';" +
+    "                                                                          " +
+    "}";
+
+var change_log = new Array();
+function Changer() {
+  Debug.LiveEditChangeScript(script, patch_pos, orig_body.length, new_body_patch, change_log);
+  print("Change log: " + JSON.stringify(change_log) + "\n");
+}
+
+function NoOp() {
+}
+
+function CallM(changer) {
+  // We expect call IC here after several function runs.
+  return BeingReplaced(changer);
+}
+
+// This several iterations should cause call IC for BeingReplaced call. This IC
+// will keep reference to code object of BeingRepalced function. This reference
+// should also be patched. Unfortunately, this is a manually checked fact (from
+// debugger or debug print) and doesn't work as an automatic test.
+CallM(NoOp);
+CallM(NoOp);
+CallM(NoOp);
+
+var res = CallM(Changer);
+assertEquals("Capybara", res);