[compiler-rt][rtsan] Introduce rtsan_interface.h and ScopedDisabler (llvm#106736)

Author: cjappl

compiler-rt/include/CMakeLists.txt

@@ -10,6 +10,7 @@ if (COMPILER_RT_BUILD_SANITIZERS)
     sanitizer/lsan_interface.h
     sanitizer/msan_interface.h
     sanitizer/netbsd_syscall_hooks.h
+    sanitizer/rtsan_interface.h
     sanitizer/scudo_interface.h
     sanitizer/tsan_interface.h
     sanitizer/tsan_interface_atomic.h

compiler-rt/include/sanitizer/rtsan_interface.h

@@ -0,0 +1,75 @@
+//===-- sanitizer/rtsan_interface.h -----------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is a part of RealtimeSanitizer.
+//
+// Public interface header.
+//===----------------------------------------------------------------------===//
+
+#ifndef SANITIZER_RTSAN_INTERFACE_H
+#define SANITIZER_RTSAN_INTERFACE_H
+
+#include <sanitizer/common_interface_defs.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif // __cplusplus
+
+// Disable all RTSan error reporting.
+// Must be paired with a call to `__rtsan_enable`
+void SANITIZER_CDECL __rtsan_disable(void);
+
+// Re-enable all RTSan error reporting.
+// Must follow a call to `__rtsan_disable`.
+void SANITIZER_CDECL __rtsan_enable(void);
+
+#ifdef __cplusplus
+} // extern "C"
+
+namespace __rtsan {
+#if defined(__has_feature) && __has_feature(realtime_sanitizer)
+
+class ScopedDisabler {
+public:
+  ScopedDisabler() { __rtsan_disable(); }
+  ~ScopedDisabler() { __rtsan_enable(); }
+
+#if __cplusplus >= 201103L
+  ScopedDisabler(const ScopedDisabler &) = delete;
+  ScopedDisabler &operator=(const ScopedDisabler &) = delete;
+  ScopedDisabler(ScopedDisabler &&) = delete;
+  ScopedDisabler &operator=(ScopedDisabler &&) = delete;
+#else
+private:
+  ScopedDisabler(const ScopedDisabler &);
+  ScopedDisabler &operator=(const ScopedDisabler &);
+#endif // __cplusplus >= 201103L
+};
+
+#else
+
+class ScopedDisabler {
+public:
+  ScopedDisabler() {}
+#if __cplusplus >= 201103L
+  ScopedDisabler(const ScopedDisabler &) = delete;
+  ScopedDisabler &operator=(const ScopedDisabler &) = delete;
+  ScopedDisabler(ScopedDisabler &&) = delete;
+  ScopedDisabler &operator=(ScopedDisabler &&) = delete;
+#else
+private:
+  ScopedDisabler(const ScopedDisabler &);
+  ScopedDisabler &operator=(const ScopedDisabler &);
+#endif // __cplusplus >= 201103L
+};
+
+#endif // defined(__has_feature) && __has_feature(realtime_sanitizer)
+} // namespace __rtsan
+#endif // __cplusplus
+
+#endif // SANITIZER_RTSAN_INTERFACE_H

compiler-rt/lib/rtsan/rtsan.h

@@ -36,12 +36,10 @@ SANITIZER_INTERFACE_ATTRIBUTE void __rtsan_realtime_enter();
 // intercepted method calls to the real methods.
 SANITIZER_INTERFACE_ATTRIBUTE void __rtsan_realtime_exit();
 
-// Disable all RTSan error reporting.
-// Injected into the code if "nosanitize(realtime)" is on a function.
+// See documentation in rtsan_interface.h.
 SANITIZER_INTERFACE_ATTRIBUTE void __rtsan_disable();
 
-// Re-enable all RTSan error reporting.
-// The counterpart to `__rtsan_disable`.
+// See documentation in rtsan_interface.h.
 SANITIZER_INTERFACE_ATTRIBUTE void __rtsan_enable();
 
 SANITIZER_INTERFACE_ATTRIBUTE void

compiler-rt/test/rtsan/disabler.cpp

@@ -0,0 +1,53 @@
+// RUN: %clangxx -fsanitize=realtime %s -o %t
+// RUN: not %run %t 2>&1 | FileCheck %s
+// RUN: %clangxx %s -fsanitize=realtime -o - -S -emit-llvm | FileCheck %s --check-prefix=CHECK-ENABLED-IR
+// RUN: %clangxx %s -o - -S -emit-llvm | FileCheck %s --check-prefix=CHECK-DISABLED-IR
+// UNSUPPORTED: ios
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "sanitizer/rtsan_interface.h"
+
+void violation() [[clang::nonblocking]] {
+  void *ptr;
+  {
+    __rtsan::ScopedDisabler disabler{};
+    ptr = malloc(2);
+    fprintf(stderr, "Allocated pointer %p in disabled context\n", ptr);
+  }
+
+  // ensure nested disablers don't interfere with one another
+  {
+    void *ptr2;
+    __rtsan::ScopedDisabler disabler{};
+    {
+      __rtsan::ScopedDisabler disabler2{};
+      ptr2 = malloc(2);
+      fprintf(stderr, "Allocated second pointer %p in disabled context\n",
+              ptr2);
+    }
+
+    free(ptr2);
+    fprintf(stderr, "Free'd second pointer in disabled context\n");
+  }
+
+  free(ptr);
+}
+
+int main() {
+  violation();
+  return 0;
+  // CHECK: Allocated pointer {{.*}} in disabled context
+  // CHECK: Allocated second pointer {{.*}} in disabled context
+  // CHECK: Free'd second pointer in disabled context
+  // CHECK: {{.*Real-time violation.*}}
+  // CHECK-NOT: {{.*malloc*}}
+  // CHECK-NEXT: {{.*free.*}}
+}
+
+// CHECK-ENABLED-IR: {{.*@__rtsan_disable.*}}
+// CHECK-ENABLED-IR: {{.*@__rtsan_enable.*}}
+
+// CHECK-DISABLED-IR-NOT: {{.*__rtsan_disable.*}}
+// CHECK-DISABLED-IR-NOT: {{.*__rtsan_enable.*}}