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

[Naomi Musgrave via llvm-commits]

I have looked repeatedly into a fix for this bug, with no progress yet. I'm
currently repressing it to be able to proceed with investigating other bugs.
If I have not resolved this issue before my internship is over, I think it
may be better to file bugs against these issues.

Note: commit reverted in rL246450 due to it breaking a flaky build.

On Mon, Aug 31, 2015 at 9:23 AM, Eric Christopher <echristo at gmail.com>
wrote:

>
>
>> Summary: In response to bug 24578, reported against failing LLVM test.
>>
>>
> FWIW we generally just say "PR24578"
>
> So, hrm, how long do we expect the "workaround" annotation to be in the
> source?
>
> -eric
>
>
>
>> 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);
>>
>>
>> _______________________________________________
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>> llvm-commits at lists.llvm.org
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>>
>


-- 
- Naomi Musgrave
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