[llvm] 905f874 - [cmake] Add LLVM_UBSAN_FLAGS, to allow overriding UBSan flags

[Vedant Kumar via llvm-commits]

Author: Vedant Kumar
Date: 2020-10-26T15:48:19-07:00
New Revision: 905f874c449cc114d74eaeb19639664779fd0b6e

URL: https://github.com/llvm/llvm-project/commit/905f874c449cc114d74eaeb19639664779fd0b6e
DIFF: https://github.com/llvm/llvm-project/commit/905f874c449cc114d74eaeb19639664779fd0b6e.diff

LOG: [cmake] Add LLVM_UBSAN_FLAGS, to allow overriding UBSan flags

Allow overriding the default set of flags used to enable UBSan when
building llvm.

This can be used to test new checks or opt out of certain checks.

Differential Revision: https://reviews.llvm.org/D89439

Added: 
    

Modified: 
    llvm/CMakeLists.txt
    llvm/cmake/modules/HandleLLVMOptions.cmake
    llvm/docs/CMake.rst

Removed: 
    


################################################################################
diff  --git a/llvm/CMakeLists.txt b/llvm/CMakeLists.txt
index ebc6733b5873..21563e151180 100644
--- a/llvm/CMakeLists.txt
+++ b/llvm/CMakeLists.txt
@@ -487,6 +487,10 @@ endif( LLVM_USE_PERF )
 set(LLVM_USE_SANITIZER "" CACHE STRING
   "Define the sanitizer used to build binaries and tests.")
 option(LLVM_OPTIMIZE_SANITIZED_BUILDS "Pass -O1 on debug sanitizer builds" ON)
+set(LLVM_UBSAN_FLAGS
+    "-fsanitize=undefined -fno-sanitize=vptr,function -fno-sanitize-recover=all"
+    CACHE STRING
+    "Compile flags set to enable UBSan. Only used if LLVM_USE_SANITIZER contains 'Undefined'.")
 set(LLVM_LIB_FUZZING_ENGINE "" CACHE PATH
   "Path to fuzzing library for linking with fuzz targets")
 

diff  --git a/llvm/cmake/modules/HandleLLVMOptions.cmake b/llvm/cmake/modules/HandleLLVMOptions.cmake
index ddf2b6e3b688..78ed1c06ac9d 100644
--- a/llvm/cmake/modules/HandleLLVMOptions.cmake
+++ b/llvm/cmake/modules/HandleLLVMOptions.cmake
@@ -776,8 +776,7 @@ if(LLVM_USE_SANITIZER)
       endif()
     elseif (LLVM_USE_SANITIZER STREQUAL "Undefined")
       append_common_sanitizer_flags()
-      append("-fsanitize=undefined -fno-sanitize=vptr,function -fno-sanitize-recover=all"
-              CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
+      append("${LLVM_UBSAN_FLAGS}" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
     elseif (LLVM_USE_SANITIZER STREQUAL "Thread")
       append_common_sanitizer_flags()
       append("-fsanitize=thread" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
@@ -786,8 +785,8 @@ if(LLVM_USE_SANITIZER)
     elseif (LLVM_USE_SANITIZER STREQUAL "Address;Undefined" OR
             LLVM_USE_SANITIZER STREQUAL "Undefined;Address")
       append_common_sanitizer_flags()
-      append("-fsanitize=address,undefined -fno-sanitize=vptr,function -fno-sanitize-recover=all"
-              CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
+      append("-fsanitize=address" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
+      append("${LLVM_UBSAN_FLAGS}" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
     elseif (LLVM_USE_SANITIZER STREQUAL "Leaks")
       append_common_sanitizer_flags()
       append("-fsanitize=leak" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)

diff  --git a/llvm/docs/CMake.rst b/llvm/docs/CMake.rst
index 5a73b7d45211..bb821b417ad9 100644
--- a/llvm/docs/CMake.rst
+++ b/llvm/docs/CMake.rst
@@ -428,6 +428,11 @@ LLVM-specific variables
   are ``Address``, ``Memory``, ``MemoryWithOrigins``, ``Undefined``, ``Thread``,
   ``DataFlow``, and ``Address;Undefined``. Defaults to empty string.
 
+**LLVM_UBSAN_FLAGS**:STRING
+  Defines the set of compile flags used to enable UBSan. Only used if
+  ``LLVM_USE_SANITIZER`` contains ``Undefined``. This can be used to override
+  the default set of UBSan flags.
+
 **LLVM_ENABLE_LTO**:STRING
   Add ``-flto`` or ``-flto=`` flags to the compile and link command
   lines, enabling link-time optimization. Possible values are ``Off``,