[llvm] r246449 - Repress sanitization on User dtor. Modify msan macros for applying attribute

[Naomi Musgrave via llvm-commits]

Author: nmusgrave
Date: Mon Aug 31 10:57:40 2015
New Revision: 246449

URL: http://llvm.org/viewvc/llvm-project?rev=246449&view=rev
Log:
Repress sanitization on User dtor. Modify msan macros for applying attribute
to repress sanitization. Move attribute for repressing sanitization to
operator delete for User, MDNode.

Summary: In response to bug 24578, reported against failing LLVM test.

Reviewers: chandlerc, rsmith, eugenis

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D12335

Modified:
    llvm/trunk/include/llvm/IR/User.h
    llvm/trunk/include/llvm/Support/Compiler.h
    llvm/trunk/lib/IR/Metadata.cpp
    llvm/trunk/lib/IR/User.cpp

Modified: llvm/trunk/include/llvm/IR/User.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/IR/User.h?rev=246449&r1=246448&r2=246449&view=diff
==============================================================================
--- llvm/trunk/include/llvm/IR/User.h (original)
+++ llvm/trunk/include/llvm/IR/User.h Mon Aug 31 10:57:40 2015
@@ -72,8 +72,7 @@ protected:
   void growHungoffUses(unsigned N, bool IsPhi = false);
 
 public:
-  ~User() override {
-  }
+  ~User() override {}
   /// \brief Free memory allocated for User and Use objects.
   void operator delete(void *Usr);
   /// \brief Placement delete - required by std, but never called.

Modified: llvm/trunk/include/llvm/Support/Compiler.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/Compiler.h?rev=246449&r1=246448&r2=246449&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Support/Compiler.h (original)
+++ llvm/trunk/include/llvm/Support/Compiler.h Mon Aug 31 10:57:40 2015
@@ -323,10 +323,12 @@
 #if __has_feature(memory_sanitizer)
 # define LLVM_MEMORY_SANITIZER_BUILD 1
 # include <sanitizer/msan_interface.h>
+# define LLVM_NO_SANITIZE_MEMORY_ATTRIBUTE __attribute__((no_sanitize_memory))
 #else
 # define LLVM_MEMORY_SANITIZER_BUILD 0
 # define __msan_allocated_memory(p, size)
 # define __msan_unpoison(p, size)
+# define LLVM_NO_SANITIZE_MEMORY_ATTRIBUTE
 #endif
 
 /// \macro LLVM_ADDRESS_SANITIZER_BUILD

Modified: llvm/trunk/lib/IR/Metadata.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/Metadata.cpp?rev=246449&r1=246448&r2=246449&view=diff
==============================================================================
--- llvm/trunk/lib/IR/Metadata.cpp (original)
+++ llvm/trunk/lib/IR/Metadata.cpp Mon Aug 31 10:57:40 2015
@@ -401,7 +401,9 @@ void *MDNode::operator new(size_t Size,
   return Ptr;
 }
 
-void MDNode::operator delete(void *Mem) {
+// Repress memory sanitization, due to use-after-destroy by operator
+// delete. Bug report 24578 identifies this issue.
+LLVM_NO_SANITIZE_MEMORY_ATTRIBUTE void MDNode::operator delete(void *Mem) {
   MDNode *N = static_cast<MDNode *>(Mem);
   size_t OpSize = N->NumOperands * sizeof(MDOperand);
   OpSize = RoundUpToAlignment(OpSize, llvm::alignOf<uint64_t>());

Modified: llvm/trunk/lib/IR/User.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/User.cpp?rev=246449&r1=246448&r2=246449&view=diff
==============================================================================
--- llvm/trunk/lib/IR/User.cpp (original)
+++ llvm/trunk/lib/IR/User.cpp Mon Aug 31 10:57:40 2015
@@ -118,7 +118,9 @@ void *User::operator new(size_t Size) {
 //                         User operator delete Implementation
 //===----------------------------------------------------------------------===//
 
-void User::operator delete(void *Usr) {
+// Repress memory sanitization, due to use-after-destroy by operator
+// delete. Bug report 24578 identifies this issue.
+LLVM_NO_SANITIZE_MEMORY_ATTRIBUTE void User::operator delete(void *Usr) {
   // Hung off uses use a single Use* before the User, while other subclasses
   // use a Use[] allocated prior to the user.
   User *Obj = static_cast<User *>(Usr);