+}
+
+void AddressSanitizer::createInitializerPoisonCalls(Module &M,
+ Value *FirstAddr,
+ Value *LastAddr) {
+ // We do all of our poisoning and unpoisoning within _GLOBAL__I_a.
+ Function *GlobalInit = M.getFunction("_GLOBAL__I_a");
+ // If that function is not present, this TU contains no globals, or they have
+ // all been optimized away
+ if (!GlobalInit)
+ return;
+
+ // Set up the arguments to our poison/unpoison functions.
+ IRBuilder<> IRB(GlobalInit->begin()->getFirstInsertionPt());
+
+ // Declare our poisoning and unpoisoning functions.
+ Function *AsanPoisonGlobals = checkInterfaceFunction(M.getOrInsertFunction(
+ kAsanPoisonGlobalsName, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
+ AsanPoisonGlobals->setLinkage(Function::ExternalLinkage);
+ Function *AsanUnpoisonGlobals = checkInterfaceFunction(M.getOrInsertFunction(
+ kAsanUnpoisonGlobalsName, IRB.getVoidTy(), NULL));
+ AsanUnpoisonGlobals->setLinkage(Function::ExternalLinkage);
+
+ // Add a call to poison all external globals before the given function starts.
+ IRB.CreateCall2(AsanPoisonGlobals, FirstAddr, LastAddr);
+
+ // Add calls to unpoison all globals before each return instruction.
+ for (Function::iterator I = GlobalInit->begin(), E = GlobalInit->end();
+ I != E; ++I) {
+ if (ReturnInst *RI = dyn_cast<ReturnInst>(I->getTerminator())) {
+ CallInst::Create(AsanUnpoisonGlobals, "", RI);
+ }
+ }
+}
+
+bool AddressSanitizer::ShouldInstrumentGlobal(GlobalVariable *G) {
+ Type *Ty = cast<PointerType>(G->getType())->getElementType();
+ DEBUG(dbgs() << "GLOBAL: " << *G << "\n");
+
+ if (BL->isIn(*G)) return false;
+ if (!Ty->isSized()) return false;
+ if (!G->hasInitializer()) return false;
+ // Touch only those globals that will not be defined in other modules.
+ // Don't handle ODR type linkages since other modules may be built w/o asan.
+ if (G->getLinkage() != GlobalVariable::ExternalLinkage &&
+ G->getLinkage() != GlobalVariable::PrivateLinkage &&
+ G->getLinkage() != GlobalVariable::InternalLinkage)
+ return false;
+ // Two problems with thread-locals:
+ // - The address of the main thread's copy can't be computed at link-time.
+ // - Need to poison all copies, not just the main thread's one.
+ if (G->isThreadLocal())
+ return false;
+ // For now, just ignore this Alloca if the alignment is large.
+ if (G->getAlignment() > RedzoneSize) return false;
+
+ // Ignore all the globals with the names starting with "\01L_OBJC_".
+ // Many of those are put into the .cstring section. The linker compresses
+ // that section by removing the spare \0s after the string terminator, so
+ // our redzones get broken.
+ if ((G->getName().find("\01L_OBJC_") == 0) ||
+ (G->getName().find("\01l_OBJC_") == 0)) {
+ DEBUG(dbgs() << "Ignoring \\01L_OBJC_* global: " << *G);
+ return false;
+ }
+
+ if (G->hasSection()) {
+ StringRef Section(G->getSection());
+ // Ignore the globals from the __OBJC section. The ObjC runtime assumes
+ // those conform to /usr/lib/objc/runtime.h, so we can't add redzones to
+ // them.
+ if ((Section.find("__OBJC,") == 0) ||
+ (Section.find("__DATA, __objc_") == 0)) {
+ DEBUG(dbgs() << "Ignoring ObjC runtime global: " << *G);
+ return false;
+ }
+ // See http://code.google.com/p/address-sanitizer/issues/detail?id=32
+ // Constant CFString instances are compiled in the following way:
+ // -- the string buffer is emitted into
+ // __TEXT,__cstring,cstring_literals
+ // -- the constant NSConstantString structure referencing that buffer
+ // is placed into __DATA,__cfstring
+ // Therefore there's no point in placing redzones into __DATA,__cfstring.
+ // Moreover, it causes the linker to crash on OS X 10.7
+ if (Section.find("__DATA,__cfstring") == 0) {
+ DEBUG(dbgs() << "Ignoring CFString: " << *G);
+ return false;
+ }
+ }
+
+ return true;