Limit SMP-only symbols to SMP-enabled builds in gensymbol

[al3xtjames]

gensymbol was updated in #5594 to support the openblas_set_threads_callback_function symbol. This caused SMP-disabled builds to regress as openblas_set_threads_callback_function is only defined when SMP is enabled. Fix this by updating gensymbol to conditionally add the symbol when SMP is enabled.

The compilation failure can be reproduced with make USE_THREAD=0:

./gensymbol osx x86_64 "_" 1 0  0 0 0 0 "" "" 1 0 0 1 1 1 1 > osx.def
cc -O2 -DSMALL_MATRIX_OPT -DMAX_STACK_ALLOC=2048 -DEXPRECISION -Wall -m64 -DF_INTERFACE_GFORT -fPIC -DC_LAPACK -DNO_WARMUP -DMAX_CPU_NUMBER=32 -DMAX_PARALLEL_NUMBER=1 -DBUILD_SINGLE=1 -DBUILD_DOUBLE=1 -DBUILD_COMPLEX=1 -DBUILD_COMPLEX16=1 -DVERSION=\"0.3.31.dev\" -msse3 -mssse3 -msse4.1 -mavx -mavx2 -mavx2 -UASMNAME -UASMFNAME -UNAME -UCNAME -UCHAR_NAME -UCHAR_CNAME -DASMNAME=_ -DASMFNAME=__ -DNAME=_ -DCNAME= -DCHAR_NAME=\"_\" -DCHAR_CNAME=\"\" -DNO_AFFINITY -I..  -all_load -headerpad_max_install_names -install_name "/Users/alex/Projects/OpenBLAS/exports/../libopenblas.0.dylib" -dynamiclib -o ../libopenblas_haswell-r0.3.31.dev.dylib ../libopenblas_haswell-r0.3.31.dev.a -Wl,-exported_symbols_list,osx.def
Undefined symbols for architecture x86_64:
  "_openblas_set_threads_callback_function", referenced from:
      <initial-undefines>
ld: symbol(s) not found for architecture x86_64

[al3xtjames]

The gensymbol calls in CMakeLists.txt need to be updated but I haven't been able to test it (it doesn't appear to be used on macOS or Linux):

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4f0e82096..41f2813fe 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -538,7 +538,7 @@ endif()
  #if (USE_PERL)
 message(STATUS "adding postbuild instruction to rename syms")
   add_custom_command(TARGET ${OpenBLAS_LIBNAME}_static POST_BUILD
-	COMMAND perl ${PROJECT_SOURCE_DIR}/exports/gensymbol.pl "win2k" "${ARCH}" "${BU}" "${EXPRECISION_IN}" "${NO_CBLAS_IN}" "${NO_LAPACK_IN}" "${NO_LAPACKE_IN}" "${NEED2UNDERSCORES_IN}" "${ONLY_CBLAS_IN}" "${SYMBOLPREFIX}" "${SYMBOLSUFFIX}" "${BLD}" "${BBF16}" "${BHF16}" "${BS}" "${BD}" "${BC}" "${BZ}" > ${PROJECT_BINARY_DIR}/renamesyms.def
+	COMMAND perl ${PROJECT_SOURCE_DIR}/exports/gensymbol.pl "win2k" "${ARCH}" "${BU}" "${EXPRECISION_IN}" "${NO_CBLAS_IN}" "${NO_LAPACK_IN}" "${NO_LAPACKE_IN}" "${NEED2UNDERSCORES_IN}" "${ONLY_CBLAS_IN}" "${SYMBOLPREFIX}" "${SYMBOLSUFFIX}" "${BLD}" "${BBF16}" "${BHF16}" "${BS}" "${BD}" "${BC}" "${BZ}" "${USE_THREAD}" > ${PROJECT_BINARY_DIR}/renamesyms.def
 	COMMAND ${CMAKE_C_COMPILER} ${CMAKE_C_FLAGS} -I${PROJECT_SOURCE_DIR} -I${PROJECT_BINARY_DIR} -c -o ${PROJECT_BINARY_DIR}/dllinit.o ${PROJECT_SOURCE_DIR}/exports/dllinit.c
 	COMMAND lld-link -nodefaultlib:libcmt -defaultlib:${CRTLIB} ${CMAKE_LINKER_FLAGS} -errorlimit:0 -def:${PROJECT_BINARY_DIR}/renamesyms.def ${PROJECT_BINARY_DIR}/dllinit.o $<TARGET_FILE:${OpenBLAS_LIBNAME}_static> -wholearchive:$<TARGET_FILE:${OpenBLAS_LIBNAME}_static> -dll -out:$<TARGET_FILE_DIR:${OpenBLAS_LIBNAME}_static>/${OpenBLAS_LIBNAME}.dll -implib:$<TARGET_FILE_DIR:${OpenBLAS_LIBNAME}_static>/${OpenBLAS_LIBNAME}.dll.a ${PDBOPT} 
 	#COMMAND lld-link -nodefaultlib:libcmt -defaultlib:msvcrt ${CMAKE_LINKER_FLAGS} -errorlimit:0 -def:${PROJECT_BINARY_DIR}/renamesyms.def ${PROJECT_BINARY_DIR}/dllinit.o $<TARGET_FILE:${OpenBLAS_LIBNAME}_static> -wholearchive:$<TARGET_FILE:${OpenBLAS_LIBNAME}_static> -dll -out:$<TARGET_FILE_DIR:${OpenBLAS_LIBNAME}_static>/${OpenBLAS_LIBNAME}.dll -implib:$<TARGET_FILE_DIR:${OpenBLAS_LIBNAME}_static>/${OpenBLAS_LIBNAME}.dll.a
@@ -548,13 +548,13 @@ message(STATUS "adding postbuild instruction to rename syms")
   else ()
   if (NOT USE_PERL)
   add_custom_command(TARGET ${OpenBLAS_LIBNAME}_shared POST_BUILD
-	  COMMAND sh ${PROJECT_SOURCE_DIR}/exports/gensymbol "objcopy" "${ARCH}" "${BU}" "${EXPRECISION_IN}" "${NO_CBLAS_IN}" "${NO_LAPACK_IN}" "${NO_LAPACKE_IN}" "${NEED2UNDERSCORES_IN}" "${ONLY_CBLAS_IN}" \"${SYMBOLPREFIX}\" \"${SYMBOLSUFFIX}\" "${BLD}" "${BBF16}" "${BHF16}" "${BS}" "${BD}" "${BC}" "${BZ}" > ${PROJECT_BINARY_DIR}/objcopy.def
+	  COMMAND sh ${PROJECT_SOURCE_DIR}/exports/gensymbol "objcopy" "${ARCH}" "${BU}" "${EXPRECISION_IN}" "${NO_CBLAS_IN}" "${NO_LAPACK_IN}" "${NO_LAPACKE_IN}" "${NEED2UNDERSCORES_IN}" "${ONLY_CBLAS_IN}" \"${SYMBOLPREFIX}\" \"${SYMBOLSUFFIX}\" "${BLD}" "${BBF16}" "${BHF16}" "${BS}" "${BD}" "${BC}" "${BZ}" "${USE_THREAD}" > ${PROJECT_BINARY_DIR}/objcopy.def
     COMMAND objcopy --redefine-syms ${PROJECT_BINARY_DIR}/objcopy.def  ${PROJECT_BINARY_DIR}/lib/${OpenBLAS_LIBNAME}.so
     COMMENT "renaming symbols"
     )
   else()
   add_custom_command(TARGET ${OpenBLAS_LIBNAME}_shared POST_BUILD
-    COMMAND perl ${PROJECT_SOURCE_DIR}/exports/gensymbol.pl "objcopy" "${ARCH}" "${BU}" "${EXPRECISION_IN}" "${NO_CBLAS_IN}" "${NO_LAPACK_IN}" "${NO_LAPACKE_IN}" "${NEED2UNDERSCORES_IN}" "${ONLY_CBLAS_IN}" \"${SYMBOLPREFIX}\" \"${SYMBOLSUFFIX}\" "${BLD}" "${BBF16}" "${BHF16}" "${BS}" "${BD}" "${BC}" "${BZ}" > ${PROJECT_BINARY_DIR}/objcopy.def
+    COMMAND perl ${PROJECT_SOURCE_DIR}/exports/gensymbol.pl "objcopy" "${ARCH}" "${BU}" "${EXPRECISION_IN}" "${NO_CBLAS_IN}" "${NO_LAPACK_IN}" "${NO_LAPACKE_IN}" "${NEED2UNDERSCORES_IN}" "${ONLY_CBLAS_IN}" \"${SYMBOLPREFIX}\" \"${SYMBOLSUFFIX}\" "${BLD}" "${BBF16}" "${BHF16}" "${BS}" "${BD}" "${BC}" "${BZ}" "${USE_THREAD}" > ${PROJECT_BINARY_DIR}/objcopy.def
     COMMAND objcopy --redefine-syms ${PROJECT_BINARY_DIR}/objcopy.def  ${PROJECT_BINARY_DIR}/lib/lib${OpenBLAS_LIBNAME}.so
     COMMENT "renaming symbols"
     )

[martin-frbg]

Thanks (I notice this got reported as #5607 - it might be easier to add it as an empty function in non-SMP builds ?

[al3xtjames]

#5615 fixes it for me, thanks! I'll close this PR as it's no longer needed.