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]

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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