Bug 1362403 - update source coordinates after emitting loop bodies; r=jimb

MozReview-Commit-ID: CEJV2nSvg24

--HG--
extra : rebase_source : d607b725e4841233e176c639a8ec5c42ca7e86b4

js/src/frontend/BytecodeEmitter.cpp

@@ -7280,6 +7280,10 @@ BytecodeEmitter::emitForOf(ParseNode* forOfLoop, EmitterScope* headLexicalEmitte
         auto loopDepth = this->stackDepth;
 #endif
 
+        // Make sure this code is attributed to the "for".
+        if (!updateSourceCoordNotes(forOfHead->pn_pos.begin))
+            return false;
+
         if (!emit1(JSOP_POP))                             // ITER
             return false;
         if (!emit1(JSOP_DUP))                             // ITER ITER
@@ -7488,6 +7492,10 @@ BytecodeEmitter::emitForIn(ParseNode* forInLoop, EmitterScope* headLexicalEmitte
     // Set offset for continues.
     loopInfo.continueTarget = { offset() };
 
+    // Make sure this code is attributed to the "for".
+    if (!updateSourceCoordNotes(forInHead->pn_pos.begin))
+        return false;
+
     if (!emitLoopEntry(nullptr, initialJump))             // ITER ITERVAL
         return false;
     if (!emit1(JSOP_POP))                                 // ITER

js/src/jit-test/tests/debug/Frame-onStep-17.js

@@ -0,0 +1,31 @@
+var g = newGlobal();
+var dbg = new Debugger;
+var gw = dbg.addDebuggee(g);
+var log;
+var previous;
+
+dbg.onDebuggerStatement = function (frame) {
+  let debugLine = frame.script.getOffsetLocation(frame.offset).lineNumber;
+  log = '';
+  previous = '';
+  frame.onStep = function() {
+    let foundLine = this.script.getOffsetLocation(this.offset).lineNumber;
+    if (this.script.getLineOffsets(foundLine).indexOf(this.offset) >= 0) {
+      let thisline = (foundLine - debugLine).toString(16);
+      if (thisline !== previous) {
+        log += thisline;
+        previous = thisline;
+      }
+    }
+  };
+};
+
+function testOne(loopKind) {
+  let body = "var array = [2, 4, 6];\ndebugger;\nfor (let iter " +
+      loopKind + " array) {\n  print(iter);\n}\n";
+  g.eval(body);
+  assertEq(log, "12121212");
+}
+
+testOne("in");
+testOne("of");