1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/xpcom/analysis/stack.js Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,159 @@
1.4 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.5 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.6 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.7 +
1.8 +require({ after_gcc_pass: "cfg" });
1.9 +
1.10 +include("gcc_util.js");
1.11 +include("unstable/lazy_types.js");
1.12 +
1.13 +function process_type(c)
1.14 +{
1.15 + if ((c.kind == 'class' || c.kind == 'struct') &&
1.16 + !c.isIncomplete)
1.17 + isStack(c);
1.18 +}
1.19 +
1.20 +/**
1.21 + * A BlameChain records a chain of one or more location/message pairs. It
1.22 + * can be used to issue a complex error message such as:
1.23 + * location: error: Allocated class Foo on the heap
1.24 + * locationofFoo: class Foo inherits from class Bar
1.25 + * locationofBar: in class Bar
1.26 + * locationofBarMem: Member Bar::mFoo
1.27 + * locationofBaz: class Baz is annotated NS_STACK
1.28 + */
1.29 +function BlameChain(loc, message, prev)
1.30 +{
1.31 + this.loc = loc;
1.32 + this.message = message;
1.33 + this.prev = prev;
1.34 +}
1.35 +
1.36 +BlameChain.prototype.toString = function()
1.37 +{
1.38 + let loc = this.loc;
1.39 + if (loc === undefined)
1.40 + loc = "<unknown location>";
1.41 +
1.42 + let str = '%s: %s'.format(loc.toString(), this.message);
1.43 + if (this.prev)
1.44 + str += "\n%s".format(this.prev);
1.45 + return str;
1.46 +};
1.47 +
1.48 +function isStack(c)
1.49 +{
1.50 + function calculate()
1.51 + {
1.52 + if (hasAttribute(c, 'NS_stack'))
1.53 + return new BlameChain(c.loc, '%s %s is annotated NS_STACK_CLASS'.format(c.kind, c.name));
1.54 +
1.55 + for each (let base in c.bases) {
1.56 + let r = isStack(base.type);
1.57 + if (r != null)
1.58 + return new BlameChain(c.loc, '%s %s is a base of %s %s'.format(base.type.kind, base.type.name, c.kind, c.name), r);
1.59 + }
1.60 +
1.61 + for each (let member in c.members) {
1.62 + if (member.isFunction)
1.63 + continue;
1.64 +
1.65 + if (hasAttribute(member, 'NS_okonheap'))
1.66 + continue;
1.67 +
1.68 + let type = member.type;
1.69 + while (true) {
1.70 + if (type === undefined)
1.71 + break;
1.72 +
1.73 + if (type.isArray) {
1.74 + type = type.type;
1.75 + continue;
1.76 + }
1.77 +
1.78 + if (type.typedef) {
1.79 + if (hasAttribute(type, 'NS_stack'))
1.80 + return true;
1.81 +
1.82 + type = type.typedef;
1.83 + continue;
1.84 + }
1.85 + break;
1.86 + }
1.87 +
1.88 + if (type === undefined) {
1.89 + warning("incomplete type for member " + member + ".", member.loc);
1.90 + continue;
1.91 + }
1.92 +
1.93 + if (type.isPointer || type.isReference)
1.94 + continue;
1.95 +
1.96 + if (!type.kind || (type.kind != 'class' && type.kind != 'struct'))
1.97 + continue;
1.98 +
1.99 + let r = isStack(type);
1.100 + if (r != null)
1.101 + return new BlameChain(c.loc, 'In class %s'.format(c.name),
1.102 + new BlameChain(member.loc, 'Member %s'.format(member.name), r));
1.103 + }
1.104 + return null;
1.105 + }
1.106 +
1.107 + if (!c.hasOwnProperty('isStack'))
1.108 + c.isStack = calculate();
1.109 +
1.110 + return c.isStack;
1.111 +}
1.112 +
1.113 +function process_tree(fn)
1.114 +{
1.115 + if (hasAttribute(dehydra_convert(fn), 'NS_suppress_stackcheck'))
1.116 + return;
1.117 +
1.118 + let cfg = function_decl_cfg(fn);
1.119 +
1.120 + for (let bb in cfg_bb_iterator(cfg)) {
1.121 + let it = bb_isn_iterator(bb);
1.122 + for (let isn in it) {
1.123 + if (isn.tree_code() != GIMPLE_CALL)
1.124 + continue;
1.125 +
1.126 + let name = gimple_call_function_name(isn);
1.127 + if (name != "operator new" && name != "operator new []")
1.128 + continue;
1.129 +
1.130 + // ignore placement new
1.131 + // TODO? ensure 2nd arg is local stack variable
1.132 + if (gimple_call_num_args(isn) == 2 &&
1.133 + TREE_TYPE(gimple_call_arg(isn, 1)).tree_code() == POINTER_TYPE)
1.134 + continue;
1.135 +
1.136 + let newLhs = gimple_call_lhs(isn);
1.137 + if (!newLhs)
1.138 + error("Non assigning call to operator new", location_of(isn));
1.139 +
1.140 + // if isn is the last of its block there are other problems...
1.141 + assign = it.next();
1.142 +
1.143 + // Calls to |new| are always followed by an assignment, casting the void ptr to which
1.144 + // |new| was assigned, to a ptr variable of the same type as the allocated object.
1.145 + // Exception: explicit calls to |::operator new (size_t)|, which can be ignored.
1.146 + if (assign.tree_code() != GIMPLE_ASSIGN)
1.147 + continue;
1.148 +
1.149 + let assignRhs = gimple_op(assign, 1);
1.150 + if (newLhs != assignRhs)
1.151 + continue;
1.152 +
1.153 + let assignLhs = gimple_op(assign, 0);
1.154 + let type = TREE_TYPE(TREE_TYPE(assignLhs));
1.155 + let dehydraType = dehydra_convert(type);
1.156 +
1.157 + let r = isStack(dehydraType);
1.158 + if (r)
1.159 + warning("constructed object of type '%s' not on the stack: %s".format(dehydraType.name, r), location_of(isn));
1.160 + }
1.161 + }
1.162 +}
