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

1 files changed, 50 insertions, 0 deletions

diff --git a/lib/ubsan_minimal/CMakeLists.txt b/lib/ubsan_minimal/CMakeLists.txt
new file mode 100644
index 000000000..c75f5090a
--- /dev/null
+++ b/lib/ubsan_minimal/CMakeLists.txt
@@ -0,0 +1,50 @@
+# Build for the undefined behavior sanitizer runtime support library.
+
+set(UBSAN_MINIMAL_SOURCES
+  ubsan_minimal_handlers.cc
+  )
+
+include_directories(..)
+
+set(UBSAN_CFLAGS ${SANITIZER_COMMON_CFLAGS})
+append_rtti_flag(OFF UBSAN_CFLAGS)
+
+set(UBSAN_STANDALONE_CFLAGS ${SANITIZER_COMMON_CFLAGS})
+append_rtti_flag(OFF UBSAN_STANDALONE_CFLAGS)
+
+add_compiler_rt_component(ubsan-minimal)
+
+# Common parts of UBSan runtime.
+add_compiler_rt_object_libraries(RTUbsan_minimal
+  ARCHS ${UBSAN_COMMON_SUPPORTED_ARCH}
+  SOURCES ${UBSAN_MINIMAL_SOURCES} CFLAGS ${UBSAN_CFLAGS})
+
+
+if(COMPILER_RT_HAS_UBSAN)
+  # Initializer of standalone UBSan runtime.
+
+  # Standalone UBSan runtimes.
+  add_compiler_rt_runtime(clang_rt.ubsan_minimal
+    STATIC
+    ARCHS ${UBSAN_SUPPORTED_ARCH}
+    OBJECT_LIBS RTUbsan_minimal
+    CFLAGS ${UBSAN_CFLAGS}
+    PARENT_TARGET ubsan-minimal)
+
+  add_compiler_rt_runtime(clang_rt.ubsan_minimal
+    SHARED
+    ARCHS ${UBSAN_SUPPORTED_ARCH}
+    OBJECT_LIBS RTUbsan_minimal
+    CFLAGS ${UBSAN_CFLAGS}
+    LINK_LIBS ${UBSAN_DYNAMIC_LIBS}
+    PARENT_TARGET ubsan-minimal)
+
+  if (UNIX)
+    set(ARCHS_FOR_SYMBOLS ${UBSAN_SUPPORTED_ARCH})
+    list(REMOVE_ITEM ARCHS_FOR_SYMBOLS i386 i686)
+    add_sanitizer_rt_symbols(clang_rt.ubsan_minimal
+      ARCHS ${ARCHS_FOR_SYMBOLS}
+      PARENT_TARGET ubsan-minimal
+      EXTRA ubsan.syms.extra)
+  endif()
+endif()