[GWP-ASan] Initial build files, implementation of PRNG [1].

Summary:
See D60593 for further information.
This patch slices off the PRNG implementation and the initial build files for GWP-ASan.

Reviewers: vlad.tsyrklevich, morehouse, vitalybuka

Reviewed By: morehouse

Subscribers: srhines, kubamracek, mgorny, #sanitizers, llvm-commits, cryptoad, eugenis

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D61867

llvm-svn: 360710

compiler-rt/cmake/config-ix.cmake

@@ -246,6 +246,7 @@ else()
   set(ALL_FUZZER_SUPPORTED_ARCH ${X86_64} ${ARM64})
 endif()
 
+set(ALL_GWP_ASAN_SUPPORTED_ARCH ${X86} ${X86_64} ${ARM64} ${ARM32})
 if(APPLE)
   set(ALL_LSAN_SUPPORTED_ARCH ${X86} ${X86_64} ${MIPS64} ${ARM64})
 else()
@@ -445,6 +446,9 @@ if(APPLE)
   list_intersect(DFSAN_SUPPORTED_ARCH
     ALL_DFSAN_SUPPORTED_ARCH
     SANITIZER_COMMON_SUPPORTED_ARCH)
+  list_intersect(GWP_ASAN_SUPPORTED_ARCH
+    ALL_GWP_ASAN_SUPPORTED_ARCH
+    SANITIZER_COMMON_SUPPORTED_ARCH)
   list_intersect(LSAN_SUPPORTED_ARCH
     ALL_LSAN_SUPPORTED_ARCH
     SANITIZER_COMMON_SUPPORTED_ARCH)
@@ -513,6 +517,7 @@ else()
   filter_available_targets(XRAY_SUPPORTED_ARCH ${ALL_XRAY_SUPPORTED_ARCH})
   filter_available_targets(SHADOWCALLSTACK_SUPPORTED_ARCH
     ${ALL_SHADOWCALLSTACK_SUPPORTED_ARCH})
+  filter_available_targets(GWP_ASAN_SUPPORTED_ARCH ${ALL_GWP_ASAN_SUPPORTED_ARCH})
 endif()
 
 if (MSVC)
@@ -534,7 +539,7 @@ if(COMPILER_RT_SUPPORTED_ARCH)
 endif()
 message(STATUS "Compiler-RT supported architectures: ${COMPILER_RT_SUPPORTED_ARCH}")
 
-set(ALL_SANITIZERS asan;dfsan;msan;hwasan;tsan;safestack;cfi;scudo;ubsan_minimal)
+set(ALL_SANITIZERS asan;dfsan;msan;hwasan;tsan;safestack;cfi;scudo;ubsan_minimal;gwp_asan)
 set(COMPILER_RT_SANITIZERS_TO_BUILD all CACHE STRING
     "sanitizers to build if supported on the target (all;${ALL_SANITIZERS})")
 list_replace(COMPILER_RT_SANITIZERS_TO_BUILD all "${ALL_SANITIZERS}")
@@ -678,3 +683,13 @@ if (COMPILER_RT_HAS_SANITIZER_COMMON AND SHADOWCALLSTACK_SUPPORTED_ARCH AND
 else()
   set(COMPILER_RT_HAS_SHADOWCALLSTACK FALSE)
 endif()
+
+# Note: Fuchsia and Windows are not currently supported by GWP-ASan. Support
+# is planned for these platforms. Darwin is also not supported due to TLS
+# calling malloc on first use.
+if (GWP_ASAN_SUPPORTED_ARCH AND OS_NAME MATCHES "Android|Linux")
+  set(COMPILER_RT_HAS_GWP_ASAN TRUE)
+else()
+  set(COMPILER_RT_HAS_GWP_ASAN FALSE)
+endif()
+pythonize_bool(COMPILER_RT_HAS_GWP_ASAN)

compiler-rt/lib/gwp_asan/CMakeLists.txt

@@ -0,0 +1,36 @@
+add_compiler_rt_component(gwp_asan)
+
+include_directories(..)
+
+set(GWP_ASAN_SOURCES
+  random.cpp
+)
+
+set(GWP_ASAN_HEADERS
+  random.h
+)
+
+# Disable RTTI and exception support, as we want these libraries to be
+# C-compatible. Regular C source files can be linked against the generated
+# GwpAsan libraries using the Clang C compiler.
+set(GWP_ASAN_CFLAGS -fno-rtti -fno-exceptions)
+
+if (COMPILER_RT_HAS_GWP_ASAN)
+  foreach(arch ${GWP_ASAN_SUPPORTED_ARCH})
+    add_compiler_rt_runtime(
+      clang_rt.gwp_asan
+      STATIC
+      ARCHS ${arch}
+      SOURCES ${GWP_ASAN_SOURCES}
+      ADDITIONAL_HEADERS ${GWP_ASAN_HEADERS}
+      CFLAGS ${GWP_ASAN_CFLAGS}
+      PARENT_TARGET gwp_asan
+    )
+  endforeach()
+
+  add_compiler_rt_object_libraries(RTGwpAsan
+      ARCHS ${GWP_ASAN_SUPPORTED_ARCH}
+      SOURCES ${GWP_ASAN_SOURCES}
+      ADDITIONAL_HEADERS ${GWP_ASAN_HEADERS}
+      CFLAGS ${GWP_ASAN_CFLAGS})
+endif()

compiler-rt/lib/gwp_asan/random.cpp

@@ -0,0 +1,21 @@
+//===-- random.cpp ----------------------------------------------*- 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "gwp_asan/random.h"
+
+#include <ctime>
+
+namespace gwp_asan {
+uint32_t getRandomUnsigned32() {
+  thread_local uint32_t RandomState = static_cast<uint64_t>(time(nullptr));
+  RandomState ^= RandomState << 13;
+  RandomState ^= RandomState >> 17;
+  RandomState ^= RandomState << 5;
+  return RandomState;
+}
+} // namespace gwp_asan

compiler-rt/lib/gwp_asan/random.h

@@ -0,0 +1,20 @@
+//===-- random.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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef GWP_ASAN_RANDOM_H_
+#define GWP_ASAN_RANDOM_H_
+
+#include <cstdint>
+
+namespace gwp_asan {
+// xorshift (32-bit output), extremely fast PRNG that uses arithmetic operations
+// only. Seeded using walltime.
+uint32_t getRandomUnsigned32();
+} // namespace gwp_asan
+
+#endif // GWP_ASAN_RANDOM_H_