Bug 601398 - Use new instructions, rather than source notes, to obtain block chain (r=igor)

js/src/jsemit.cpp

@@ -1514,15 +1514,20 @@ EmitNonLocalJumpFixup(JSContext *cx, JSCodeGenerator *cg, JSStmtInfo *toStmt)
 }
 
 static JSBool
-EmitBlockChain(JSContext *cx, JSCodeGenerator *cg)
+EmitKnownBlockChain(JSContext *cx, JSCodeGenerator *cg, JSObjectBox *box)
 {
-    JSObjectBox *box = cg->blockChainBox;
     if (box)
         return EmitIndexOp(cx, JSOP_BLOCKCHAIN, box->index, cg);
     else
         return js_Emit1(cx, cg, JSOP_NULLBLOCKCHAIN) >= 0;
 }
 
+static JSBool
+EmitBlockChain(JSContext *cx, JSCodeGenerator *cg)
+{
+    return EmitKnownBlockChain(cx, cg, cg->blockChainBox);
+}
+
 static ptrdiff_t
 EmitGoto(JSContext *cx, JSCodeGenerator *cg, JSStmtInfo *toStmt,
          ptrdiff_t *lastp, JSAtomListElement *label, JSSrcNoteType noteType)
@@ -1541,7 +1546,14 @@ EmitGoto(JSContext *cx, JSCodeGenerator *cg, JSStmtInfo *toStmt,
     if (index < 0)
         return -1;
 
-    return EmitBackPatchOp(cx, cg, JSOP_BACKPATCH, lastp);
+    ptrdiff_t result = EmitBackPatchOp(cx, cg, JSOP_BACKPATCH, lastp);
+    if (result < 0)
+        return result;
+
+    if (!EmitBlockChain(cx, cg))
+        return -1;
+
+    return result;
 }
 
 static JSBool
@@ -5368,16 +5380,17 @@ js_EmitTree(JSContext *cx, JSCodeGenerator *cg, JSParseNode *pn)
 
         tryEnd = CG_OFFSET(cg);
 
+        JSObjectBox *prevBox = NULL;
         /* If this try has a catch block, emit it. */
         pn2 = pn->pn_kid2;
         lastCatch = NULL;
         if (pn2) {
-            JSObjectBox *prevBox = NULL;
             uintN count = 0;    /* previous catch block's population */
             
             /*
              * The emitted code for a catch block looks like:
              *
+             * blockchain
              * [throwing]                          only if 2nd+ catch block
              * [leaveblock]                        only if 2nd+ catch block
              * enterblock                          with SRC_CATCH
@@ -5403,6 +5416,9 @@ js_EmitTree(JSContext *cx, JSCodeGenerator *cg, JSParseNode *pn)
                 JS_ASSERT(cg->stackDepth == depth);
                 guardJump = GUARDJUMP(stmtInfo);
                 if (guardJump != -1) {
+                    if (EmitKnownBlockChain(cx, cg, prevBox) < 0)
+                        return JS_FALSE;
+                
                     /* Fix up and clean up previous catch block. */
                     CHECK_AND_SET_JUMP_OFFSET_AT(cx, cg, guardJump);
 
@@ -5487,6 +5503,9 @@ js_EmitTree(JSContext *cx, JSCodeGenerator *cg, JSParseNode *pn)
          * stack unbalanced.
          */
         if (lastCatch && lastCatch->pn_kid2) {
+            if (EmitKnownBlockChain(cx, cg, prevBox) < 0)
+                return JS_FALSE;
+            
             CHECK_AND_SET_JUMP_OFFSET_AT(cx, cg, GUARDJUMP(stmtInfo));
 
             /* Sync the stack to take into account pushed exception. */
@@ -5501,6 +5520,9 @@ js_EmitTree(JSContext *cx, JSCodeGenerator *cg, JSParseNode *pn)
                 js_Emit1(cx, cg, JSOP_THROW) < 0) {
                 return JS_FALSE;
             }
+
+            if (EmitBlockChain(cx, cg) < 0)
+                return JS_FALSE;
         }
 
         JS_ASSERT(cg->stackDepth == depth);
@@ -5682,6 +5704,8 @@ js_EmitTree(JSContext *cx, JSCodeGenerator *cg, JSParseNode *pn)
             CG_BASE(cg)[top] = JSOP_SETRVAL;
             if (js_Emit1(cx, cg, JSOP_RETRVAL) < 0)
                 return JS_FALSE;
+            if (EmitBlockChain(cx, cg) < 0)
+                return JS_FALSE;
         }
         break;
 

js/src/jsinterp.cpp

@@ -181,28 +181,29 @@ js_GetBlockChain(JSContext *cx, JSStackFrame *fp)
     jsbytecode *pc = fp->hasImacropc() ? fp->imacropc() : fp->pc(cx);
     
     JS_ASSERT(pc >= start && pc < script->code + script->length);
-    
-    ptrdiff_t oplen;
-    JSObject *blockChain = NULL;
-    for (jsbytecode *p = start; p < pc; p += oplen) {
-        JSOp op = js_GetOpcode(cx, script, p);
-        const JSCodeSpec *cs = &js_CodeSpec[op];
-        oplen = cs->length;
-        if (oplen < 0)
-            oplen = js_GetVariableBytecodeLength(p);
 
-        if (op == JSOP_ENTERBLOCK) { 
-            blockChain = script->getObject(GET_INDEX(p));
-        } else if (op == JSOP_LEAVEBLOCK || op == JSOP_LEAVEBLOCKEXPR) {
-            /*
-             * Some LEAVEBLOCK instructions are due to early exits via
-             * return/break/etc. from block-scoped loops and functions.
-             * We should ignore these instructions, since they don't really
-             * signal the end of the block.
-             */
-            jssrcnote *sn = js_GetSrcNote(script, p);
-            if (!(sn && SN_TYPE(sn) == SRC_HIDDEN))
+    JSObject *blockChain = NULL;
+    if (*pc == JSOP_BLOCKCHAIN) {
+        blockChain = script->getObject(GET_INDEX(pc));
+    } else if (*pc == JSOP_NULLBLOCKCHAIN) {
+        blockChain = NULL;
+    } else {
+        ptrdiff_t oplen;
+        for (jsbytecode *p = start; p < pc; p += oplen) {
+            JSOp op = js_GetOpcode(cx, script, p);
+            const JSCodeSpec *cs = &js_CodeSpec[op];
+            oplen = cs->length;
+            if (oplen < 0)
+                oplen = js_GetVariableBytecodeLength(p);
+            
+            if (op == JSOP_ENTERBLOCK)
+                blockChain = script->getObject(GET_INDEX(p));
+            else if (op == JSOP_LEAVEBLOCK || op == JSOP_LEAVEBLOCKEXPR)
                 blockChain = blockChain->getParent();
+            else if (op == JSOP_BLOCKCHAIN)
+                blockChain = script->getObject(GET_INDEX(p));
+            else if (op == JSOP_NULLBLOCKCHAIN)
+                blockChain = NULL;
         }
     }
 
@@ -6746,8 +6747,6 @@ END_CASE(JSOP_ARRAYPUSH)
 
             switch (tn->kind) {
               case JSTRY_CATCH:
-                JS_ASSERT(js_GetOpcode(cx, regs.fp->script(), regs.pc) == JSOP_ENTERBLOCK);
-
 #if JS_HAS_GENERATORS
                 /* Catch cannot intercept the closing of a generator. */
                 if (JS_UNLIKELY(cx->exception.isMagic(JS_GENERATOR_CLOSING)))

js/src/trace-test/tests/jaeger/bug563000/trap-self-as-parent.js

@@ -4,7 +4,7 @@ x = "notset";
 function myparent(nested) {
   if (nested) {
     /* noop call in myparent */
-    trap(myparent, 49, "success()");
+    trap(myparent, 50, "success()");
   } else {
     myparent(true);
     x = "failure";

js/src/trace-test/tests/jaeger/bug563000/trap-self-from-trap.js

@@ -13,7 +13,7 @@ function myparent(nested) {
   }
 }
 /* JSOP_CALL to doNothing in myparent with nested = false. */
-trap(myparent, 35, "myparent(true)");
+trap(myparent, 36, "myparent(true)");
 
 function success() {
   x = "success";