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

[Evgenii Stepanov via llvm-commits]

Yes, but with this suppression we can do it earlier. Also, this
after-destruction access looks quite intentional, and we may decide
not to fix it at all. Anyway, it sounds like it may take a while.


On Mon, Aug 31, 2015 at 12:36 PM, Eric Christopher <echristo at gmail.com> wrote:
> Right, but sooner or later should probably mean "when we're clean" and not
> at other times? Or am I missing something?
>
> -eric
>
> On Mon, Aug 31, 2015 at 12:35 PM Evgenii Stepanov <eugenis at google.com>
> wrote:
>>
>> We have the options, and they are off by default at this point. But we
>> want to enable them on the sanitizer bootstrap bot sooner or later.
>>
>>
>> On Mon, Aug 31, 2015 at 12:26 PM, Naomi Musgrave <nmusgrave at google.com>
>> wrote:
>> > I'm not entirely sure if the compile and runtime options for
>> > use-after-dtor
>> > poisoning will be fully integrated into MSan or not when I leave. To
>> > clarify, are you reccommending leaving these as distinct options?
>> >
>> > On Mon, Aug 31, 2015 at 12:22 PM, Eric Christopher <echristo at gmail.com>
>> > wrote:
>> >>
>> >>
>> >>
>> >> On Mon, Aug 31, 2015 at 10:36 AM Naomi Musgrave <nmusgrave at google.com>
>> >> wrote:
>> >>>
>> >>> 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.
>> >>
>> >>
>> >> OK. That seems reasonable.
>> >>
>> >>>
>> >>> If I have not resolved this issue before my internship is over, I
>> >>> think
>> >>> it may be better to file bugs against these issues.
>> >>>
>> >>
>> >> *nod* Might be worth an option to disable the feature in general so we
>> >> don't need the source annotations?
>> >>
>> >> -eric
>> >>
>> >>>
>> >>> 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);
>> >>>>>
>> >>>>>
>> >>>>> _______________________________________________
>> >>>>> llvm-commits mailing list
>> >>>>> llvm-commits at lists.llvm.org
>> >>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>> >>>
>> >>>
>> >>>
>> >>>
>> >>> --
>> >>> - Naomi Musgrave
>> >>>
>> >
>> >
>> >
>> > --
>> > - Naomi Musgrave
>> >