Minimal runtime for UBSan.

Summary:
An implementation of ubsan runtime library suitable for use in production.

Minimal attack surface.
* No stack traces.
* Definitely no C++ demangling.
* No UBSAN_OPTIONS=log_file=/path (very suid-unfriendly). And no UBSAN_OPTIONS in general.
* as simple as possible

Minimal CPU and RAM overhead.
* Source locations unnecessary in the presence of (split) debug info.
* Values and types (as in A+B overflows T) can be reconstructed from register/stack dumps, once you know what type of error you are looking at.
* above two items save 3% binary size.

When UBSan is used with -ftrap-function=abort, sometimes it is hard to reason about failures. This library replaces abort with a slightly more informative message without much extra overhead. Since ubsan interface in not stable, this code must reside in compiler-rt.

Reviewers: pcc, kcc

Subscribers: srhines, mgorny, aprantl, krytarowski, llvm-commits

Differential Revision: https://reviews.llvm.org/D36810

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@312029 91177308-0d34-0410-b5e6-96231b3b80d8

6 files changed, 145 insertions, 0 deletions

diff --git a/test/ubsan_minimal/CMakeLists.txt b/test/ubsan_minimal/CMakeLists.txt
new file mode 100644
index 000000000..8e87b76bc
--- /dev/null
+++ b/test/ubsan_minimal/CMakeLists.txt
@@ -0,0 +1,23 @@
+set(UBSAN_LIT_TESTS_DIR ${CMAKE_CURRENT_SOURCE_DIR})
+
+set(UBSAN_TEST_ARCH ${UBSAN_SUPPORTED_ARCH})
+
+set(UBSAN_TESTSUITES)
+set(UBSAN_TEST_DEPS ${SANITIZER_COMMON_LIT_TEST_DEPS})
+if(NOT COMPILER_RT_STANDALONE_BUILD)
+  list(APPEND UBSAN_TEST_DEPS ubsan-minimal)
+endif()
+
+foreach(arch ${UBSAN_TEST_ARCH})
+  get_test_cc_for_arch(${arch} UBSAN_TEST_TARGET_CC UBSAN_TEST_TARGET_CFLAGS)
+  set(CONFIG_NAME ${arch})
+  configure_lit_site_cfg(
+    ${CMAKE_CURRENT_SOURCE_DIR}/lit.site.cfg.in
+    ${CMAKE_CURRENT_BINARY_DIR}/${CONFIG_NAME}/lit.site.cfg)
+  list(APPEND UBSAN_TESTSUITES ${CMAKE_CURRENT_BINARY_DIR}/${CONFIG_NAME})
+endforeach()
+
+add_lit_testsuite(check-ubsan-minimal "Running UndefinedBehaviorSanitizerMinimal tests"
+  ${UBSAN_TESTSUITES}
+  DEPENDS ${UBSAN_TEST_DEPS})
+set_target_properties(check-ubsan-minimal PROPERTIES FOLDER "Compiler-RT Misc")
diff --git a/test/ubsan_minimal/TestCases/recover-dedup-limit.cpp b/test/ubsan_minimal/TestCases/recover-dedup-limit.cpp
new file mode 100644
index 000000000..faa2b66ad
--- /dev/null
+++ b/test/ubsan_minimal/TestCases/recover-dedup-limit.cpp
@@ -0,0 +1,41 @@
+// RUN: %clangxx -fsanitize=signed-integer-overflow -fsanitize-recover=all %s -o %t && %run %t 2>&1 | FileCheck %s
+
+#include <stdint.h>
+
+#define OVERFLOW  \
+  x = 0x7FFFFFFE; \
+  x += __LINE__
+
+int main() {
+  int32_t x;
+  OVERFLOW;  // CHECK: add-overflow
+  OVERFLOW;  // CHECK: add-overflow
+  OVERFLOW;  // CHECK: add-overflow
+  OVERFLOW;  // CHECK: add-overflow
+  OVERFLOW;  // CHECK: add-overflow
+
+  OVERFLOW;  // CHECK: add-overflow
+  OVERFLOW;  // CHECK: add-overflow
+  OVERFLOW;  // CHECK: add-overflow
+  OVERFLOW;  // CHECK: add-overflow
+  OVERFLOW;  // CHECK: add-overflow
+
+  OVERFLOW;  // CHECK: add-overflow
+  OVERFLOW;  // CHECK: add-overflow
+  OVERFLOW;  // CHECK: add-overflow
+  OVERFLOW;  // CHECK: add-overflow
+  OVERFLOW;  // CHECK: add-overflow
+
+  OVERFLOW;  // CHECK: add-overflow
+  OVERFLOW;  // CHECK: add-overflow
+  OVERFLOW;  // CHECK: add-overflow
+  OVERFLOW;  // CHECK: add-overflow
+  OVERFLOW;  // CHECK: add-overflow
+
+  // CHECK-NOT: add-overflow
+  OVERFLOW;  // CHECK: too many errors
+  // CHECK-NOT: add-overflow
+  OVERFLOW;
+  OVERFLOW;
+  OVERFLOW;
+}
diff --git a/test/ubsan_minimal/TestCases/recover-dedup.cpp b/test/ubsan_minimal/TestCases/recover-dedup.cpp
new file mode 100644
index 000000000..744471c66
--- /dev/null
+++ b/test/ubsan_minimal/TestCases/recover-dedup.cpp
@@ -0,0 +1,25 @@
+// RUN: %clangxx -fsanitize=signed-integer-overflow -fsanitize-recover=all %s -o %t && %run %t 2>&1 | FileCheck %s
+
+#include <stdint.h>
+
+__attribute__((noinline))
+int f(int x, int y) {
+  // CHECK: mul-overflow
+  return x * y;
+}
+
+__attribute__((noinline))
+int g(int x, int y) {
+  // CHECK: mul-overflow
+  return x * (y + 1);
+}
+
+int main() {
+  int x = 2;
+  for (int i = 0; i < 10; ++i)
+    x = f(x, x);
+  x = 2;
+  for (int i = 0; i < 10; ++i)
+    x = g(x, x);
+  // CHECK-NOT: mul-overflow
+}
diff --git a/test/ubsan_minimal/TestCases/uadd-overflow.cpp b/test/ubsan_minimal/TestCases/uadd-overflow.cpp
new file mode 100644
index 000000000..034575012
--- /dev/null
+++ b/test/ubsan_minimal/TestCases/uadd-overflow.cpp
@@ -0,0 +1,10 @@
+// RUN: %clangxx -fsanitize=unsigned-integer-overflow %s -o %t && %run %t 2>&1 | FileCheck %s
+// RUN: %clangxx -fsanitize=unsigned-integer-overflow -fno-sanitize-recover=all %s -o %t && not --crash %run %t 2>&1 | FileCheck %s
+
+#include <stdint.h>
+
+int main() {
+  uint32_t k = 0x87654321;
+  k += 0xedcba987;
+  // CHECK: add-overflow
+}
diff --git a/test/ubsan_minimal/lit.common.cfg b/test/ubsan_minimal/lit.common.cfg
new file mode 100644
index 000000000..1bd1bbefe
--- /dev/null
+++ b/test/ubsan_minimal/lit.common.cfg
@@ -0,0 +1,35 @@
+# -*- Python -*-
+
+import os
+
+def get_required_attr(config, attr_name):
+  attr_value = getattr(config, attr_name, None)
+  if attr_value == None:
+    lit_config.fatal(
+      "No attribute %r in test configuration! You may need to run "
+      "tests from your build directory or add this attribute "
+      "to lit.site.cfg " % attr_name)
+  return attr_value
+
+# Setup source root.
+config.test_source_root = os.path.dirname(__file__)
+
+def build_invocation(compile_flags):
+  return " " + " ".join([config.clang] + compile_flags) + " "
+
+target_cflags = [get_required_attr(config, "target_cflags")]
+clang_ubsan_cflags = ["-fsanitize-minimal-runtime"] + target_cflags
+clang_ubsan_cxxflags = config.cxx_mode_flags + clang_ubsan_cflags
+
+# Define %clang and %clangxx substitutions to use in test RUN lines.
+config.substitutions.append( ("%clang ", build_invocation(clang_ubsan_cflags)) )
+config.substitutions.append( ("%clangxx ", build_invocation(clang_ubsan_cxxflags)) )
+
+# Default test suffixes.
+config.suffixes = ['.c', '.cc', '.cpp']
+
+# Check that the host supports UndefinedBehaviorSanitizerMinimal tests
+if config.host_os not in ['Darwin', 'Linux', 'FreeBSD', 'NetBSD']: # TODO: Windows
+  config.unsupported = True
+
+config.available_features.add('arch=' + config.target_arch)
diff --git a/test/ubsan_minimal/lit.site.cfg.in b/test/ubsan_minimal/lit.site.cfg.in
new file mode 100644
index 000000000..d4dd68ef2
--- /dev/null
+++ b/test/ubsan_minimal/lit.site.cfg.in
@@ -0,0 +1,11 @@
+@LIT_SITE_CFG_IN_HEADER@
+
+# Tool-specific config options.
+config.target_cflags = "@UBSAN_TEST_TARGET_CFLAGS@"
+config.target_arch = "@UBSAN_TEST_TARGET_ARCH@"
+
+# Load common config for all compiler-rt lit tests.
+lit_config.load_config(config, "@COMPILER_RT_BINARY_DIR@/test/lit.common.configured")
+
+# Load tool-specific config that would do the real work.
+lit_config.load_config(config, "@UBSAN_LIT_TESTS_DIR@/lit.common.cfg")