The Tor Browser: js/src/frontend/ParseNode.cpp@6474c204b198 (annotated)

js/src/frontend/ParseNode.cpp@6474c204b198 (annotated)

js/src/frontend/ParseNode.cpp

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
  * vim: set ts=8 sts=4 et sw=4 tw=99:
  * This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #include "frontend/ParseNode-inl.h"
 #include "frontend/Parser.h"
 #include "jscntxtinlines.h"
 using namespace js;
 using namespace js::frontend;
 using mozilla::IsFinite;
 /*
  * Asserts to verify assumptions behind pn_ macros.
  */
 #define pn_offsetof(m)  offsetof(ParseNode, m)
 JS_STATIC_ASSERT(pn_offsetof(pn_link) == pn_offsetof(dn_uses));
 #undef pn_offsetof
 #ifdef DEBUG
 void
 ParseNode::checkListConsistency()
 {
     JS_ASSERT(isArity(PN_LIST));
     ParseNode **tail;
     uint32_t count = 0;
     if (pn_head) {
         ParseNode *pn, *last;
         for (pn = last = pn_head; pn; last = pn, pn = pn->pn_next, count++)
             ;
         tail = &last->pn_next;
     } else {
         tail = &pn_head;
     }
     JS_ASSERT(pn_tail == tail);
     JS_ASSERT(pn_count == count);
 }
 #endif
 /* Add |node| to |parser|'s free node list. */
 void
 ParseNodeAllocator::freeNode(ParseNode *pn)
 {
     /* Catch back-to-back dup recycles. */
     JS_ASSERT(pn != freelist);
     /*
      * It's too hard to clear these nodes from the AtomDefnMaps, etc. that
      * hold references to them, so we never free them. It's our caller's job to
      * recognize and process these, since their children do need to be dealt
      * with.
      */
     JS_ASSERT(!pn->isUsed());
     JS_ASSERT(!pn->isDefn());
 #ifdef DEBUG
     /* Poison the node, to catch attempts to use it without initializing it. */
     memset(pn, 0xab, sizeof(*pn));
 #endif
     pn->pn_next = freelist;
     freelist = pn;
 }
 namespace {
 /*
  * A work pool of ParseNodes. The work pool is a stack, chained together
  * by nodes' pn_next fields. We use this to avoid creating deep C++ stacks
  * when recycling deep parse trees.
  *
  * Since parse nodes are probably allocated in something close to the order
  * they appear in a depth-first traversal of the tree, making the work pool
  * a stack should give us pretty good locality.
  */
 class NodeStack {
   public:
     NodeStack() : top(nullptr) { }
     bool empty() { return top == nullptr; }
     void push(ParseNode *pn) {
         pn->pn_next = top;
         top = pn;
     }
     void pushUnlessNull(ParseNode *pn) { if (pn) push(pn); }
     /* Push the children of the PN_LIST node |pn| on the stack. */
     void pushList(ParseNode *pn) {
         /* This clobbers pn->pn_head if the list is empty; should be okay. */
         *pn->pn_tail = top;
         top = pn->pn_head;
     }
     ParseNode *pop() {
         JS_ASSERT(!empty());
         ParseNode *hold = top; /* my kingdom for a prog1 */
         top = top->pn_next;
         return hold;
     }
   private:
     ParseNode *top;
 };
 } /* anonymous namespace */
 /*
  * Push the children of |pn| on |stack|. Return true if |pn| itself could be
  * safely recycled, or false if it must be cleaned later (pn_used and pn_defn
  * nodes, and all function nodes; see comments for CleanFunctionList in
  * SemanticAnalysis.cpp). Some callers want to free |pn|; others
  * (js::ParseNodeAllocator::prepareNodeForMutation) don't care about |pn|, and
  * just need to take care of its children.
  */
 static bool
 PushNodeChildren(ParseNode *pn, NodeStack *stack)
 {
     switch (pn->getArity()) {
       case PN_CODE:
         /*
          * Function nodes are linked into the function box tree, and may appear
          * on method lists. Both of those lists are singly-linked, so trying to
          * update them now could result in quadratic behavior when recycling
          * trees containing many functions; and the lists can be very long. So
          * we put off cleaning the lists up until just before function
          * analysis, when we call CleanFunctionList.
          *
          * In fact, we can't recycle the parse node yet, either: it may appear
          * on a method list, and reusing the node would corrupt that. Instead,
          * we clear its pn_funbox pointer to mark it as deleted;
          * CleanFunctionList recycles it as well.
          *
          * We do recycle the nodes around it, though, so we must clear pointers
          * to them to avoid leaving dangling references where someone can find
          * them.
          */
         pn->pn_funbox = nullptr;
         stack->pushUnlessNull(pn->pn_body);
         pn->pn_body = nullptr;
         return false;
       case PN_NAME:
         /*
          * Because used/defn nodes appear in AtomDefnMaps and elsewhere, we
          * don't recycle them. (We'll recover their storage when we free the
          * temporary arena.) However, we do recycle the nodes around them, so
          * clean up the pointers to avoid dangling references. The top-level
          * decls table carries references to them that later iterations through
          * the compileScript loop may find, so they need to be neat.
          *
          * pn_expr and pn_lexdef share storage; the latter isn't an owning
          * reference.
          */
         if (!pn->isUsed()) {
             stack->pushUnlessNull(pn->pn_expr);
             pn->pn_expr = nullptr;
         }
         return !pn->isUsed() && !pn->isDefn();
       case PN_LIST:
         pn->checkListConsistency();
         stack->pushList(pn);
         break;
       case PN_TERNARY:
         stack->pushUnlessNull(pn->pn_kid1);
         stack->pushUnlessNull(pn->pn_kid2);
         stack->pushUnlessNull(pn->pn_kid3);
         break;
       case PN_BINARY:
       case PN_BINARY_OBJ:
         if (pn->pn_left != pn->pn_right)
             stack->pushUnlessNull(pn->pn_left);
         stack->pushUnlessNull(pn->pn_right);
         break;
       case PN_UNARY:
         stack->pushUnlessNull(pn->pn_kid);
         break;
       case PN_NULLARY:
         return !pn->isUsed() && !pn->isDefn();
       default:
         ;
     }
     return true;
 }
 /*
  * Prepare |pn| to be mutated in place into a new kind of node. Recycle all
  * |pn|'s recyclable children (but not |pn| itself!), and disconnect it from
  * metadata structures (the function box tree).
  */
 void
 ParseNodeAllocator::prepareNodeForMutation(ParseNode *pn)
 {
     if (!pn->isArity(PN_NULLARY)) {
         /* Put |pn|'s children (but not |pn| itself) on a work stack. */
         NodeStack stack;
         PushNodeChildren(pn, &stack);
         /*
          * For each node on the work stack, push its children on the work stack,
          * and free the node if we can.
          */
         while (!stack.empty()) {
             pn = stack.pop();
             if (PushNodeChildren(pn, &stack))
                 freeNode(pn);
         }
     }
 }
 /*
  * Return the nodes in the subtree |pn| to the parser's free node list, for
  * reallocation.
  */
 ParseNode *
 ParseNodeAllocator::freeTree(ParseNode *pn)
 {
     if (!pn)
         return nullptr;
     ParseNode *savedNext = pn->pn_next;
     NodeStack stack;
     for (;;) {
         if (PushNodeChildren(pn, &stack))
             freeNode(pn);
         if (stack.empty())
             break;
         pn = stack.pop();
     }
     return savedNext;
 }
 /*
  * Allocate a ParseNode from parser's node freelist or, failing that, from
  * cx's temporary arena.
  */
 void *
 ParseNodeAllocator::allocNode()
 {
     if (ParseNode *pn = freelist) {
         freelist = pn->pn_next;
         return pn;
     }
     void *p = alloc.alloc(sizeof (ParseNode));
     if (!p)
         js_ReportOutOfMemory(cx);
     return p;
 }
 /* used only by static create methods of subclasses */
 ParseNode *
 ParseNode::create(ParseNodeKind kind, ParseNodeArity arity, FullParseHandler *handler)
 {
     const Token &tok = handler->currentToken();
     return handler->new_<ParseNode>(kind, JSOP_NOP, arity, tok.pos);
 }
 ParseNode *
 ParseNode::append(ParseNodeKind kind, JSOp op, ParseNode *left, ParseNode *right,
                   FullParseHandler *handler)
 {
     if (!left || !right)
         return nullptr;
     JS_ASSERT(left->isKind(kind) && left->isOp(op) && (js_CodeSpec[op].format & JOF_LEFTASSOC));
     ListNode *list;
     if (left->pn_arity == PN_LIST) {
         list = &left->as<ListNode>();
     } else {
         ParseNode *pn1 = left->pn_left, *pn2 = left->pn_right;
         list = handler->new_<ListNode>(kind, op, pn1);
         if (!list)
             return nullptr;
         list->append(pn2);
     }
     list->append(right);
     list->pn_pos.end = right->pn_pos.end;
     return list;
 }
 ParseNode *
 ParseNode::newBinaryOrAppend(ParseNodeKind kind, JSOp op, ParseNode *left, ParseNode *right,
                              FullParseHandler *handler, ParseContext<FullParseHandler> *pc,
                              bool foldConstants)
 {
     if (!left || !right)
         return nullptr;
     /*
      * Ensure that the parse tree is faithful to the source when "use asm" (for
      * the purpose of type checking).
      */
     if (pc->useAsmOrInsideUseAsm())
         return handler->new_<BinaryNode>(kind, op, left, right);
     /*
      * Flatten a left-associative (left-heavy) tree of a given operator into
      * a list to reduce js::FoldConstants and js::frontend::EmitTree recursion.
      */
     if (left->isKind(kind) && left->isOp(op) && (js_CodeSpec[op].format & JOF_LEFTASSOC))
         return append(kind, op, left, right, handler);
     return handler->new_<BinaryNode>(kind, op, left, right);
 }
 const char *
 Definition::kindString(Kind kind)
 {
     static const char * const table[] = {
         "", js_var_str, js_const_str, js_let_str, js_function_str, "argument", "unknown"
     };
     JS_ASSERT(unsigned(kind) <= unsigned(ARG));
     return table[kind];
 }
 namespace js {
 namespace frontend {
 /*
  * This function assumes the cloned tree is for use in the same statement and
  * binding context as the original tree.
  */
 template <>
 ParseNode *
 Parser<FullParseHandler>::cloneParseTree(ParseNode *opn)
 {
     JS_CHECK_RECURSION(context, return nullptr);
     ParseNode *pn = handler.new_<ParseNode>(opn->getKind(), opn->getOp(), opn->getArity(),
                                             opn->pn_pos);
     if (!pn)
         return nullptr;
     pn->setInParens(opn->isInParens());
     pn->setDefn(opn->isDefn());
     pn->setUsed(opn->isUsed());
     switch (pn->getArity()) {
 #define NULLCHECK(e)    JS_BEGIN_MACRO if (!(e)) return nullptr; JS_END_MACRO
       case PN_CODE:
         NULLCHECK(pn->pn_funbox = newFunctionBox(pn, opn->pn_funbox->function(), pc,
                                                  Directives(/* strict = */ opn->pn_funbox->strict),
                                                  opn->pn_funbox->generatorKind()));
         NULLCHECK(pn->pn_body = cloneParseTree(opn->pn_body));
         pn->pn_cookie = opn->pn_cookie;
         pn->pn_dflags = opn->pn_dflags;
         pn->pn_blockid = opn->pn_blockid;
         break;
       case PN_LIST:
         pn->makeEmpty();
         for (ParseNode *opn2 = opn->pn_head; opn2; opn2 = opn2->pn_next) {
             ParseNode *pn2;
             NULLCHECK(pn2 = cloneParseTree(opn2));
             pn->append(pn2);
         }
         pn->pn_xflags = opn->pn_xflags;
         break;
       case PN_TERNARY:
         NULLCHECK(pn->pn_kid1 = cloneParseTree(opn->pn_kid1));
         NULLCHECK(pn->pn_kid2 = cloneParseTree(opn->pn_kid2));
         NULLCHECK(pn->pn_kid3 = cloneParseTree(opn->pn_kid3));
         break;
       case PN_BINARY:
         NULLCHECK(pn->pn_left = cloneParseTree(opn->pn_left));
         if (opn->pn_right != opn->pn_left)
             NULLCHECK(pn->pn_right = cloneParseTree(opn->pn_right));
         else
             pn->pn_right = pn->pn_left;
         pn->pn_iflags = opn->pn_iflags;
         break;
       case PN_BINARY_OBJ:
         NULLCHECK(pn->pn_left = cloneParseTree(opn->pn_left));
         if (opn->pn_right != opn->pn_left)
             NULLCHECK(pn->pn_right = cloneParseTree(opn->pn_right));
         else
             pn->pn_right = pn->pn_left;
         pn->pn_binary_obj = opn->pn_binary_obj;
         break;
       case PN_UNARY:
         NULLCHECK(pn->pn_kid = cloneParseTree(opn->pn_kid));
         break;
       case PN_NAME:
         // PN_NAME could mean several arms in pn_u, so copy the whole thing.
         pn->pn_u = opn->pn_u;
         if (opn->isUsed()) {
             /*
              * The old name is a use of its pn_lexdef. Make the clone also be a
              * use of that definition.
              */
             Definition *dn = pn->pn_lexdef;
             pn->pn_link = dn->dn_uses;
             dn->dn_uses = pn;
         } else if (opn->pn_expr) {
             NULLCHECK(pn->pn_expr = cloneParseTree(opn->pn_expr));
             /*
              * If the old name is a definition, the new one has pn_defn set.
              * Make the old name a use of the new node.
              */
             if (opn->isDefn()) {
                 opn->setDefn(false);
                 handler.linkUseToDef(opn, (Definition *) pn);
             }
         }
         break;
       case PN_NULLARY:
         pn->pn_u = opn->pn_u;
         break;
 #undef NULLCHECK
     }
     return pn;
 }
 /*
  * Used by Parser::forStatement and comprehensionTail to clone the TARGET in
  *   for (var/const/let TARGET in EXPR)
  *
  * opn must be the pn_head of a node produced by Parser::variables, so its form
  * is known to be LHS = NAME | [LHS] | {id:LHS}.
  *
  * The cloned tree is for use only in the same statement and binding context as
  * the original tree.
  */
 template <>
 ParseNode *
 Parser<FullParseHandler>::cloneLeftHandSide(ParseNode *opn)
 {
     ParseNode *pn = handler.new_<ParseNode>(opn->getKind(), opn->getOp(), opn->getArity(),
                                             opn->pn_pos);
     if (!pn)
         return nullptr;
     pn->setInParens(opn->isInParens());
     pn->setDefn(opn->isDefn());
     pn->setUsed(opn->isUsed());
     if (opn->isArity(PN_LIST)) {
         JS_ASSERT(opn->isKind(PNK_ARRAY) || opn->isKind(PNK_OBJECT));
         pn->makeEmpty();
         for (ParseNode *opn2 = opn->pn_head; opn2; opn2 = opn2->pn_next) {
             ParseNode *pn2;
             if (opn->isKind(PNK_OBJECT)) {
                 JS_ASSERT(opn2->isArity(PN_BINARY));
                 JS_ASSERT(opn2->isKind(PNK_COLON));
                 ParseNode *tag = cloneParseTree(opn2->pn_left);
                 if (!tag)
                     return nullptr;
                 ParseNode *target = cloneLeftHandSide(opn2->pn_right);
                 if (!target)
                     return nullptr;
                 pn2 = handler.new_<BinaryNode>(PNK_COLON, JSOP_INITPROP, opn2->pn_pos, tag, target);
             } else if (opn2->isArity(PN_NULLARY)) {
                 JS_ASSERT(opn2->isKind(PNK_ELISION));
                 pn2 = cloneParseTree(opn2);
             } else {
                 pn2 = cloneLeftHandSide(opn2);
             }
             if (!pn2)
                 return nullptr;
             pn->append(pn2);
         }
         pn->pn_xflags = opn->pn_xflags;
         return pn;
     }
     JS_ASSERT(opn->isArity(PN_NAME));
     JS_ASSERT(opn->isKind(PNK_NAME));
     /* If opn is a definition or use, make pn a use. */
     pn->pn_u.name = opn->pn_u.name;
     pn->setOp(JSOP_SETNAME);
     if (opn->isUsed()) {
         Definition *dn = pn->pn_lexdef;
         pn->pn_link = dn->dn_uses;
         dn->dn_uses = pn;
     } else {
         pn->pn_expr = nullptr;
         if (opn->isDefn()) {
             /* We copied some definition-specific state into pn. Clear it out. */
             pn->pn_cookie.makeFree();
             pn->pn_dflags &= ~PND_BOUND;
             pn->setDefn(false);
             handler.linkUseToDef(pn, (Definition *) opn);
         }
     }
     return pn;
 }
 } /* namespace frontend */
 } /* namespace js */
 #ifdef DEBUG
 static const char * const parseNodeNames[] = {
 #define STRINGIFY(name) #name,
     FOR_EACH_PARSE_NODE_KIND(STRINGIFY)
 #undef STRINGIFY
 };
 void
 frontend::DumpParseTree(ParseNode *pn, int indent)
 {
     if (pn == nullptr)
         fprintf(stderr, "#NULL");
     else
         pn->dump(indent);
 }
 static void
 IndentNewLine(int indent)
 {
     fputc('\n', stderr);
     for (int i = 0; i < indent; ++i)
         fputc(' ', stderr);
 }
 void
 ParseNode::dump()
 {
     dump(0);
     fputc('\n', stderr);
 }
 void
 ParseNode::dump(int indent)
 {
     switch (pn_arity) {
       case PN_NULLARY:
         ((NullaryNode *) this)->dump();
         break;
       case PN_UNARY:
         ((UnaryNode *) this)->dump(indent);
         break;
       case PN_BINARY:
         ((BinaryNode *) this)->dump(indent);
         break;
       case PN_BINARY_OBJ:
         ((BinaryObjNode *) this)->dump(indent);
         break;
       case PN_TERNARY:
         ((TernaryNode *) this)->dump(indent);
         break;
       case PN_CODE:
         ((CodeNode *) this)->dump(indent);
         break;
       case PN_LIST:
         ((ListNode *) this)->dump(indent);
         break;
       case PN_NAME:
         ((NameNode *) this)->dump(indent);
         break;
       default:
         fprintf(stderr, "#<BAD NODE %p, kind=%u, arity=%u>",
                 (void *) this, unsigned(getKind()), unsigned(pn_arity));
         break;
     }
 }
 void
 NullaryNode::dump()
 {
     switch (getKind()) {
       case PNK_TRUE:  fprintf(stderr, "#true");  break;
       case PNK_FALSE: fprintf(stderr, "#false"); break;
       case PNK_NULL:  fprintf(stderr, "#null");  break;
       case PNK_NUMBER: {
         ToCStringBuf cbuf;
         const char *cstr = NumberToCString(nullptr, &cbuf, pn_dval);
         if (!IsFinite(pn_dval))
             fputc('#', stderr);
         if (cstr)
             fprintf(stderr, "%s", cstr);
         else
             fprintf(stderr, "%g", pn_dval);
         break;
       }
       case PNK_STRING:
         JSString::dumpChars(pn_atom->chars(), pn_atom->length());
         break;
       default:
         fprintf(stderr, "(%s)", parseNodeNames[getKind()]);
     }
 }
 void
 UnaryNode::dump(int indent)
 {
     const char *name = parseNodeNames[getKind()];
     fprintf(stderr, "(%s ", name);
     indent += strlen(name) + 2;
     DumpParseTree(pn_kid, indent);
     fprintf(stderr, ")");
 }
 void
 BinaryNode::dump(int indent)
 {
     const char *name = parseNodeNames[getKind()];
     fprintf(stderr, "(%s ", name);
     indent += strlen(name) + 2;
     DumpParseTree(pn_left, indent);
     IndentNewLine(indent);
     DumpParseTree(pn_right, indent);
     fprintf(stderr, ")");
 }
 void
 BinaryObjNode::dump(int indent)
 {
     const char *name = parseNodeNames[getKind()];
     fprintf(stderr, "(%s ", name);
     indent += strlen(name) + 2;
     DumpParseTree(pn_left, indent);
     IndentNewLine(indent);
     DumpParseTree(pn_right, indent);
     fprintf(stderr, ")");
 }
 void
 TernaryNode::dump(int indent)
 {
     const char *name = parseNodeNames[getKind()];
     fprintf(stderr, "(%s ", name);
     indent += strlen(name) + 2;
     DumpParseTree(pn_kid1, indent);
     IndentNewLine(indent);
     DumpParseTree(pn_kid2, indent);
     IndentNewLine(indent);
     DumpParseTree(pn_kid3, indent);
     fprintf(stderr, ")");
 }
 void
 CodeNode::dump(int indent)
 {
     const char *name = parseNodeNames[getKind()];
     fprintf(stderr, "(%s ", name);
     indent += strlen(name) + 2;
     DumpParseTree(pn_body, indent);
     fprintf(stderr, ")");
 }
 void
 ListNode::dump(int indent)
 {
     const char *name = parseNodeNames[getKind()];
     fprintf(stderr, "(%s [", name);
     if (pn_head != nullptr) {
         indent += strlen(name) + 3;
         DumpParseTree(pn_head, indent);
         ParseNode *pn = pn_head->pn_next;
         while (pn != nullptr) {
             IndentNewLine(indent);
             DumpParseTree(pn, indent);
             pn = pn->pn_next;
         }
     }
     fprintf(stderr, "])");
 }
 void
 NameNode::dump(int indent)
 {
     if (isKind(PNK_NAME) || isKind(PNK_DOT)) {
         if (isKind(PNK_DOT))
             fprintf(stderr, "(.");
         if (!pn_atom) {
             fprintf(stderr, "#<null name>");
         } else {
             const jschar *s = pn_atom->chars();
             size_t len = pn_atom->length();
             if (len == 0)
                 fprintf(stderr, "#<zero-length name>");
             for (size_t i = 0; i < len; i++) {
                 if (s[i] > 32 && s[i] < 127)
                     fputc(s[i], stderr);
                 else if (s[i] <= 255)
                     fprintf(stderr, "\\x%02x", (unsigned int) s[i]);
                 else
                     fprintf(stderr, "\\u%04x", (unsigned int) s[i]);
             }
         }
         if (isKind(PNK_DOT)) {
             fputc(' ', stderr);
             DumpParseTree(expr(), indent + 2);
             fputc(')', stderr);
         }
         return;
     }
     JS_ASSERT(!isUsed());
     const char *name = parseNodeNames[getKind()];
     if (isUsed())
         fprintf(stderr, "(%s)", name);
     else {
         fprintf(stderr, "(%s ", name);
         indent += strlen(name) + 2;
         DumpParseTree(expr(), indent);
         fprintf(stderr, ")");
     }
 }
 #endif
 ObjectBox::ObjectBox(JSObject *object, ObjectBox* traceLink)
   : object(object),
     traceLink(traceLink),
     emitLink(nullptr)
 {
     JS_ASSERT(!object->is<JSFunction>());
 }
 ObjectBox::ObjectBox(JSFunction *function, ObjectBox* traceLink)
   : object(function),
     traceLink(traceLink),
     emitLink(nullptr)
 {
     JS_ASSERT(object->is<JSFunction>());
     JS_ASSERT(asFunctionBox()->function() == function);
 }
 FunctionBox *
 ObjectBox::asFunctionBox()
 {
     JS_ASSERT(isFunctionBox());
     return static_cast<FunctionBox *>(this);
 }
 void
 ObjectBox::trace(JSTracer *trc)
 {
     ObjectBox *box = this;
     while (box) {
         MarkObjectRoot(trc, &box->object, "parser.object");
         if (box->isFunctionBox())
             box->asFunctionBox()->bindings.trace(trc);
         box = box->traceLink;
     }
 }

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js/src/frontend/ParseNode.cpp@6474c204b198 (annotated)

js/src/frontend/ParseNode.cpp