weaselab/conflict-set
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Remove UB from indeterminate value handling

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Move SIMD operations on potentially-indeterminate Node16::index bytes
into file-level assembly, where loading and operating on indeterminate
values is well-defined (unlike C++). Restructure scalar fallback loops
to iterate [0, numChildren) instead of [0, kMaxNodes). Fix TrivialSpan
construction from indeterminate pointers in check::Job::init and
insertPointWritesOrSorted to only construct when end.len > 0.

Add MSan toolchain to the debug CI build to catch these issues going
forward.
This commit is contained in:
andrew
2026-08-02 21:06:53 -04:00
parent 9d15af772e
commit 6fed133212
5 changed files with 154 additions and 89 deletions
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CMakeLists.txt
+18 -7
View File
@@ -5,7 +5,7 @@ project(
DESCRIPTION
"A data structure for optimistic concurrency control on ranges of bitwise-lexicographically-ordered keys."
HOMEPAGE_URL "https://git.weaselab.dev/weaselab/conflict-set"
LANGUAGES C CXX)
LANGUAGES C CXX ASM)
set(CMAKE_CXX_STANDARD 20)
file(WRITE ${CMAKE_CURRENT_BINARY_DIR}/version.txt ${PROJECT_VERSION})
@@ -130,7 +130,15 @@ endif()
set(CMAKE_CXX_IMPLICIT_LINK_LIBRARIES "")
add_library(${PROJECT_NAME}-object OBJECT ConflictSet.cpp)
# Architecture-specific SIMD assembly. These functions operate on
# potentially-indeterminate memory, which is UB in C++ but well-defined in
# assembly.
set(SIMD_ASM_FILES)
if(CMAKE_SYSTEM_PROCESSOR STREQUAL x86_64 AND NOT USE_SIMD_FALLBACK)
set(SIMD_ASM_FILES ${CMAKE_CURRENT_SOURCE_DIR}/simd_x86_64.S)
endif()
add_library(${PROJECT_NAME}-object OBJECT ConflictSet.cpp ${SIMD_ASM_FILES})
target_compile_options(${PROJECT_NAME}-object PRIVATE -fno-exceptions
-fvisibility=hidden)
target_include_directories(${PROJECT_NAME}-object
@@ -233,7 +241,7 @@ if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR AND BUILD_TESTING)
endif()
# ad hoc testing
add_executable(conflict_set_main ConflictSet.cpp)
add_executable(conflict_set_main ConflictSet.cpp ${SIMD_ASM_FILES})
target_include_directories(conflict_set_main
PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/include)
target_compile_definitions(conflict_set_main PRIVATE ENABLE_MAIN)
@@ -249,7 +257,7 @@ if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR AND BUILD_TESTING)
cmake_pop_check_state()
if(HAS_LIB_FUZZER)
add_executable(conflict_set_fuzz_test ConflictSet.cpp)
add_executable(conflict_set_fuzz_test ConflictSet.cpp ${SIMD_ASM_FILES})
target_include_directories(conflict_set_fuzz_test
PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/include)
target_compile_definitions(conflict_set_fuzz_test PRIVATE ENABLE_FUZZ)
@@ -261,7 +269,8 @@ if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR AND BUILD_TESTING)
endif()
# whitebox tests asan+ubsan
add_executable(fuzz_driver ConflictSet.cpp FuzzTestDriver.cpp)
add_executable(fuzz_driver ConflictSet.cpp FuzzTestDriver.cpp
${SIMD_ASM_FILES})
target_compile_options(fuzz_driver PRIVATE ${TEST_FLAGS})
if(NOT CMAKE_CROSSCOMPILING)
target_compile_options(fuzz_driver PRIVATE -fsanitize=address,undefined)
@@ -277,7 +286,8 @@ if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR AND BUILD_TESTING)
# whitebox tests msan
if(MSAN_TOOLCHAIN_PATH)
add_executable(fuzz_driver_msan ConflictSet.cpp FuzzTestDriver.cpp)
add_executable(fuzz_driver_msan ConflictSet.cpp FuzzTestDriver.cpp
${SIMD_ASM_FILES})
target_compile_options(fuzz_driver_msan PRIVATE ${TEST_FLAGS})
if(NOT CMAKE_CROSSCOMPILING)
target_compile_options(
@@ -304,7 +314,8 @@ if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR AND BUILD_TESTING)
# tsan tests
if(NOT CMAKE_CROSSCOMPILING AND NOT DISABLE_TSAN)
add_executable(tsan_driver ConflictSet.cpp FuzzTestDriver.cpp)
add_executable(tsan_driver ConflictSet.cpp FuzzTestDriver.cpp
${SIMD_ASM_FILES})
target_compile_options(tsan_driver PRIVATE ${TEST_FLAGS} -fsanitize=thread)
target_link_options(tsan_driver PRIVATE -fsanitize=thread)
target_compile_definitions(tsan_driver PRIVATE ENABLE_FUZZ THREAD_TEST)