run-jpegxs-tests

name	run-jpegxs-tests
description	Build and run SVT-JPEG-XS unit tests with sanitizers. Use when: running tests, ASan, MSan, TSan, UBSan, IntSan, building with clang, validating fixes, memory safety, data races, undefined behavior, integer overflow.
argument-hint	Sanitizer type (address|memory|thread|undefined|integer) and build type (debug|release)

Run JPEG-XS Tests

Parameters

• sanitizer: One of address, memory, thread, undefined, integer (default: address)
• build type: debug or release (default: debug)
• filter: Optional gtest filter pattern (default: run all tests)

Procedure

1. Build with the chosen sanitizer:

   cd Build/linux
   ./build.sh cc=clang cxx=clang++ sanitizer=<sanitizer> <build_type> test
   

2. Run tests:

   ../../Bin/<Debug|Release>/SvtJpegxsUnitTests [--gtest_filter="<filter>"]
   

3. Check output for:

   • [ PASSED ] — all tests passed
   • AddressSanitizer / MemorySanitizer / ThreadSanitizer / UndefinedBehaviorSanitizer — sanitizer errors
   • [ FAILED ] — test failures

Sanitizer Notes

Sanitizer	Detects	Flag
address	Heap/stack buffer overflow, use-after-free, double-free, leaks	-DSANITIZER=address
memory	Uninitialized memory reads	-DSANITIZER=memory
thread	Data races, deadlocks	-DSANITIZER=thread
undefined	Integer overflow, null deref, misaligned access, UB	-DSANITIZER=undefined
integer	Unsigned overflow, implicit truncation, sign changes	-DSANITIZER=integer

Integer Sanitizer (integer) Details

The integer sanitizer enables -fsanitize=integer which includes:

• unsigned-integer-overflow — unsigned arithmetic that wraps
• implicit-integer-sign-change — implicit conversions that change sign
• implicit-integer-truncation — implicit conversions that lose data

Known False Positives

The integer sanitizer reports 4 errors from GCC libstdc++ headers (not project code):

• bits/basic_string.h — npos comparison uses intentional unsigned underflow
• bits/random.tcc (×2) — Mersenne Twister uses deliberate unsigned wrapping
• bits/uniform_int_dist.h — rejection sampling uses unsigned negation

These are correct standard library behavior (C/C++ defines unsigned overflow as wrapping) and cannot be fixed in project code.

Common Fix Patterns

• Left-shift of negative values: Use LSHIFT32(val, s) macro (defined in Source/Lib/Common/Codec/Definitions.h)
• Unsigned subtraction underflow: Cast to signed type or use wider intermediate: (int32_t)(a - b)
• Implicit truncation: Add explicit cast: (uint16_t)(expr)
• Unsigned overflow in shift: Widen to uint64_t before shifting

Memory Sanitizer (memory) Details

Running MSan Tests

Unit tests (SvtJpegxsUnitTests) CANNOT run under MSan — googletest triggers a false positive in libc++ ios_base::precision during global init. Instead, test using the encoder/decoder apps:

cd Build/linux
./build.sh cc=clang cxx=clang++ sanitizer=memory debug

# Generate test input
dd if=/dev/urandom of=/tmp/test_input.yuv bs=$((1920*1080*2)) count=1

# Test encoder + decoder (use --asm avx2 or --asm c)
cd ../../Bin/Debug
./SvtJpegxsEncApp -i /tmp/test_input.yuv -w 1920 -h 1080 --input-depth 8 \
    --colour-format yuv422 -b /tmp/test.jxs --bpp 3 --asm avx2
./SvtJpegxsDecApp -i /tmp/test.jxs -o /tmp/test_dec.yuv --asm avx2

AVX-512 False Positives

MSan reports false positives in AVX-512 SIMD code paths. Clang's MSan instrumentation does not properly track initialization state through _mm512_* intrinsic expansions. The reported "origin" is a stack-allocated compiler intermediate (e.g., __I.addr.i201), not actual heap/stack memory.

Affected functions:

• dwt_horizontal_line_avx512 (Encoder: Source/Lib/Encoder/ASM_AVX512/Enc_avx512.c)
• idwt_horizontal_line_lf16_hf16_avx512 (Decoder: Source/Lib/Decoder/ASM_AVX512/idwt-avx512.c)

Verification: The C (--asm c) and AVX2 (--asm avx2) paths are MSan-clean, confirming the AVX-512 reports are false positives since all paths process the same data.

Recommendation: Always run MSan tests with --asm avx2 (or --asm c) to avoid false positives.

Important

• MSan (memory) requires all dependencies built with MSan instrumentation — expect false positives from uninstrumented libraries.
• TSan (thread) and ASan (address) cannot be combined in the same build.
• Always use clang — GCC sanitizer support is less complete.
• The integer sanitizer has ~20× runtime overhead; test runs take significantly longer.
• Filter examples: --gtest_filter="*Decoder*", --gtest_filter="*DWT*:*FRAME*"