From: Richard Smith <richard-llvm@metafoo.co.uk>
Date: Wed, 23 Aug 2017 19:39:04 +0000 (+0000)
Subject: [ubsan] PR34266: When sanitizing the 'this' value for a member function that happens... 
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=da8dca22517ea74afb2c69dae4247388b314cc3b;p=clang

[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).


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@311589 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/include/clang/AST/DeclCXX.h b/include/clang/AST/DeclCXX.h
index 289eb15690..bbd3360d75 100644
--- a/include/clang/AST/DeclCXX.h
+++ b/include/clang/AST/DeclCXX.h
@@ -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 {
diff --git a/lib/CodeGen/CodeGenFunction.cpp b/lib/CodeGen/CodeGenFunction.cpp
index 4201804e18..0df7d27107 100644
--- a/lib/CodeGen/CodeGenFunction.cpp
+++ b/lib/CodeGen/CodeGenFunction.cpp
@@ -1014,11 +1014,11 @@ void CodeGenFunction::StartFunction(GlobalDecl GD,
     }
 
     // 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);
     }
diff --git a/test/CodeGenCXX/catch-undef-behavior.cpp b/test/CodeGenCXX/catch-undef-behavior.cpp
index 179c334122..4733556c62 100644
--- a/test/CodeGenCXX/catch-undef-behavior.cpp
+++ b/test/CodeGenCXX/catch-undef-behavior.cpp
@@ -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