r311589 - [ubsan] PR34266: When sanitizing the 'this' value for a member function that happens to be a lambda call operator, use the lambda's 'this' pointer, not the captured enclosing 'this' pointer (if any).

[Adrian Prantl via cfe-commits]

I temporarily reverted the commit in r311680 to get the bots going again.

-- adrian

> On Aug 24, 2017, at 11:12 AM, Adrian Prantl via cfe-commits <cfe-commits at lists.llvm.org> wrote:
> 
> It looks like this broke / found errors on the green dragon bot:
> 
> http://green.lab.llvm.org/green/job/clang-stage2-cmake-RgSan_check/4115/consoleFull#15752874848254eaf0-7326-4999-85b0-388101f2d404
> 
> ******************** TEST 'LLVM-Unit :: ADT/./ADTTests/FilterIteratorTest.FunctionPointer' FAILED ********************
> 
> Note: Google Test filter = FilterIteratorTest.FunctionPointer
> [==========] Running 1 test from 1 test case.
> [----------] Global test environment set-up.
> [----------] 1 test from FilterIteratorTest
> [ RUN      ] FilterIteratorTest.FunctionPointer
> /Users/buildslave/jenkins/sharedspace/clang-stage2-cmake-RgSan at 2/llvm/unittests/ADT/IteratorTest.cpp:160:24: runtime error: load of null pointer of type 'const (lambda at /Users/buildslave/jenkins/sharedspace/clang-stage2-cmake-RgSan at 2/llvm/unittests/ADT/IteratorTest.cpp:160:24) *'
> SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior /Users/buildslave/jenkins/sharedspace/clang-stage2-cmake-RgSan at 2/llvm/unittests/ADT/IteratorTest.cpp:160:24 in 
> 
> ********************
> 
> -- adrian
>> On Aug 23, 2017, at 12:39 PM, Richard Smith via cfe-commits <cfe-commits at lists.llvm.org> wrote:
>> 
>> Author: rsmith
>> Date: Wed Aug 23 12:39:04 2017
>> New Revision: 311589
>> 
>> URL: http://llvm.org/viewvc/llvm-project?rev=311589&view=rev
>> Log:
>> [ubsan] PR34266: When sanitizing the 'this' value for a member function that happens to be a lambda call operator, use the lambda's 'this' pointer, not the captured enclosing 'this' pointer (if any).
>> 
>> Modified:
>>   cfe/trunk/include/clang/AST/DeclCXX.h
>>   cfe/trunk/lib/CodeGen/CodeGenFunction.cpp
>>   cfe/trunk/test/CodeGenCXX/catch-undef-behavior.cpp
>> 
>> Modified: cfe/trunk/include/clang/AST/DeclCXX.h
>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/DeclCXX.h?rev=311589&r1=311588&r2=311589&view=diff
>> ==============================================================================
>> --- cfe/trunk/include/clang/AST/DeclCXX.h (original)
>> +++ cfe/trunk/include/clang/AST/DeclCXX.h Wed Aug 23 12:39:04 2017
>> @@ -2027,7 +2027,10 @@ public:
>> 
>>  /// \brief Returns the type of the \c this pointer.
>>  ///
>> -  /// Should only be called for instance (i.e., non-static) methods.
>> +  /// Should only be called for instance (i.e., non-static) methods. Note
>> +  /// that for the call operator of a lambda closure type, this returns the
>> +  /// desugared 'this' type (a pointer to the closure type), not the captured
>> +  /// 'this' type.
>>  QualType getThisType(ASTContext &C) const;
>> 
>>  unsigned getTypeQualifiers() const {
>> 
>> Modified: cfe/trunk/lib/CodeGen/CodeGenFunction.cpp
>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CodeGenFunction.cpp?rev=311589&r1=311588&r2=311589&view=diff
>> ==============================================================================
>> --- cfe/trunk/lib/CodeGen/CodeGenFunction.cpp (original)
>> +++ cfe/trunk/lib/CodeGen/CodeGenFunction.cpp Wed Aug 23 12:39:04 2017
>> @@ -1014,11 +1014,11 @@ void CodeGenFunction::StartFunction(Glob
>>    }
>> 
>>    // Check the 'this' pointer once per function, if it's available.
>> -    if (CXXThisValue) {
>> +    if (CXXABIThisValue) {
>>      SanitizerSet SkippedChecks;
>>      SkippedChecks.set(SanitizerKind::ObjectSize, true);
>>      QualType ThisTy = MD->getThisType(getContext());
>> -      EmitTypeCheck(TCK_Load, Loc, CXXThisValue, ThisTy,
>> +      EmitTypeCheck(TCK_Load, Loc, CXXABIThisValue, ThisTy,
>>                    getContext().getTypeAlignInChars(ThisTy->getPointeeType()),
>>                    SkippedChecks);
>>    }
>> 
>> Modified: cfe/trunk/test/CodeGenCXX/catch-undef-behavior.cpp
>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/catch-undef-behavior.cpp?rev=311589&r1=311588&r2=311589&view=diff
>> ==============================================================================
>> --- cfe/trunk/test/CodeGenCXX/catch-undef-behavior.cpp (original)
>> +++ cfe/trunk/test/CodeGenCXX/catch-undef-behavior.cpp Wed Aug 23 12:39:04 2017
>> @@ -449,6 +449,27 @@ void upcast_to_vbase() {
>> }
>> }
>> 
>> +struct ThisAlign {
>> +  void this_align_lambda();
>> +};
>> +void ThisAlign::this_align_lambda() {
>> +  // CHECK-LABEL: define {{.*}}@"_ZZN9ThisAlign17this_align_lambdaEvENK3$_0clEv"
>> +  // CHECK-SAME: (%{{.*}}* %[[this:[^)]*]])
>> +  // CHECK: %[[this_addr:.*]] = alloca
>> +  // CHECK: store %{{.*}}* %[[this]], %{{.*}}** %[[this_addr]],
>> +  // CHECK: %[[this_inner:.*]] = load %{{.*}}*, %{{.*}}** %[[this_addr]],
>> +  // CHECK: %[[this_outer_addr:.*]] = getelementptr inbounds %{{.*}}, %{{.*}}* %[[this_inner]], i32 0, i32 0
>> +  // CHECK: %[[this_outer:.*]] = load %{{.*}}*, %{{.*}}** %[[this_outer_addr]],
>> +  //
>> +  // CHECK: %[[this_inner_isnonnull:.*]] = icmp ne %{{.*}}* %[[this_inner]], null
>> +  // CHECK: %[[this_inner_asint:.*]] = ptrtoint %{{.*}}* %[[this_inner]] to i
>> +  // CHECK: %[[this_inner_misalignment:.*]] = and i{{32|64}} %[[this_inner_asint]], {{3|7}},
>> +  // CHECK: %[[this_inner_isaligned:.*]] = icmp eq i{{32|64}} %[[this_inner_misalignment]], 0
>> +  // CHECK: %[[this_inner_valid:.*]] = and i1 %[[this_inner_isnonnull]], %[[this_inner_isaligned]],
>> +  // CHECK: br i1 %[[this_inner_valid:.*]]
>> +  [&] { return this; } ();
>> +}
>> +
>> namespace CopyValueRepresentation {
>>  // CHECK-LABEL: define {{.*}} @_ZN23CopyValueRepresentation2S3aSERKS0_
>>  // CHECK-NOT: call {{.*}} @__ubsan_handle_load_invalid_value
>> 
>> 
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