[PATCH] D11109: basic code generation for use-after-dtor

[Naomi Musgrave]

nmusgrave updated this revision to Diff 29618.
nmusgrave added a comment.

- helper function for dtor codegen


http://reviews.llvm.org/D11109

Files:
  lib/CodeGen/CGClass.cpp
  test/CodeGenCXX/sanitize-dtor-callback.cpp

Index: test/CodeGenCXX/sanitize-dtor-callback.cpp
===================================================================
--- /dev/null
+++ test/CodeGenCXX/sanitize-dtor-callback.cpp
@@ -0,0 +1,22 @@
+// Test -fsanitize-memory-use-after-dtor
+// RUN: %clang_cc1 -fsanitize=memory -fsanitize-memory-use-after-dtor -triple=x86_64-pc-linux -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang_cc1 -fsanitize=memory -triple=x86_64-pc-linux -emit-llvm -o - %s | FileCheck %s -check-prefix=NO_DTOR_CHECK
+
+struct Simple {
+  int x;
+  ~Simple() {}
+};
+
+int main() {
+  Simple s;
+  s.~Simple();
+}
+// Simple internal member is poisoned by compiler-generated dtor
+// CHECK-LABEL: @_ZN6SimpleD2Ev
+// CHECK: call void @__sanitizer_dtor_callback
+// CHECK: ret void
+
+// Compiling without the flag does not generate member-poisoning dtor
+// NO_DTOR_CHECK-LABEL: @_ZN6SimpleD2Ev
+// NO_DTOR_CHECK-NOT: call void @sanitizer_dtor_callback
+// NO_DTOR_CHECK: ret void
Index: lib/CodeGen/CGClass.cpp
===================================================================
--- lib/CodeGen/CGClass.cpp
+++ lib/CodeGen/CGClass.cpp
@@ -1361,6 +1361,29 @@
   return true;
 }
 
+// Generates function call for handling object poisoning, passing in
+// references to 'this' and its size as arguments.
+static void EmitDtorSanitizerCallback(CodeGenFunction &CGF,
+                                      const CXXDestructorDecl *Dtor) {
+  const ASTRecordLayout &Layout =
+      CGF.getContext().getASTRecordLayout(Dtor->getParent());
+
+  llvm::Value *Args[] = {
+    CGF.Builder.CreateBitCast(CGF.LoadCXXThis(), CGF.VoidPtrTy),
+    llvm::ConstantInt::get(CGF.SizeTy, Layout.getSize().getQuantity())
+  };
+  llvm::Type *ArgTypes[] = {
+    CGF.VoidPtrTy,
+    CGF.SizeTy
+  };
+
+  llvm::FunctionType *FnType =
+      llvm::FunctionType::get(CGF.VoidTy, ArgTypes, false);
+  llvm::Value *Fn =
+      CGF.CGM.CreateRuntimeFunction(FnType, "__sanitizer_dtor_callback");
+  CGF.EmitNounwindRuntimeCall(Fn, Args);
+}
+
 /// EmitDestructorBody - Emits the body of the current destructor.
 void CodeGenFunction::EmitDestructorBody(FunctionArgList &Args) {
   const CXXDestructorDecl *Dtor = cast<CXXDestructorDecl>(CurGD.getDecl());
@@ -1448,6 +1471,10 @@
   // Exit the try if applicable.
   if (isTryBody)
     ExitCXXTryStmt(*cast<CXXTryStmt>(Body), true);
+
+  // Insert memory-poisoning instrumentation.
+  if (CGM.getCodeGenOpts().SanitizeMemoryUseAfterDtor)
+    EmitDtorSanitizerCallback(*this, Dtor);
 }
 
 void CodeGenFunction::emitImplicitAssignmentOperatorBody(FunctionArgList &Args) {


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