[PATCH] D41301: ASan+operator new[]: Fix operator new[] cookie poisoning

[Filipe Cabecinhas via Phabricator via cfe-commits]

filcab created this revision.
filcab added reviewers: rjmccall, kcc, rsmith.

The C++ Itanium ABI says:
No cookie is required if the new operator being used is ::operator new[](size_t, void*).

We should only avoid poisoning the cookie if we're calling this
operator, not others. This is dealt with before the call to
InitializeArrayCookie.


Repository:
  rC Clang

https://reviews.llvm.org/D41301

Files:
  lib/CodeGen/ItaniumCXXABI.cpp
  test/CodeGen/address-sanitizer-and-array-cookie.cpp


Index: test/CodeGen/address-sanitizer-and-array-cookie.cpp
===================================================================
--- test/CodeGen/address-sanitizer-and-array-cookie.cpp
+++ test/CodeGen/address-sanitizer-and-array-cookie.cpp
@@ -7,7 +7,7 @@
   std::nothrow_t nothrow;
 }
 void *operator new[](size_t, const std::nothrow_t &) throw();
-void *operator new[](size_t, char *);
+void *operator new[](size_t, void *);
 
 struct C {
   int x;
@@ -53,3 +53,11 @@
 }
 // ASAN-LABEL: CallPlacementNew
 // ASAN-NOT: __asan_poison_cxx_array_cookie
+
+void *operator new[](size_t n, int);
+
+C *CallNewWithArgs() {
+// ASAN-LABEL: CallNewWithArgs
+// ASAN: call void @__asan_poison_cxx_array_cookie
+  return new (123) C[20];
+}
Index: lib/CodeGen/ItaniumCXXABI.cpp
===================================================================
--- lib/CodeGen/ItaniumCXXABI.cpp
+++ lib/CodeGen/ItaniumCXXABI.cpp
@@ -1843,8 +1843,7 @@
   llvm::Instruction *SI = CGF.Builder.CreateStore(NumElements, NumElementsPtr);
 
   // Handle the array cookie specially in ASan.
-  if (CGM.getLangOpts().Sanitize.has(SanitizerKind::Address) && AS == 0 &&
-      expr->getOperatorNew()->isReplaceableGlobalAllocationFunction()) {
+  if (CGM.getLangOpts().Sanitize.has(SanitizerKind::Address) && AS == 0) {
     // The store to the CookiePtr does not need to be instrumented.
     CGM.getSanitizerMetadata()->disableSanitizerForInstruction(SI);
     llvm::FunctionType *FTy =


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