Add FlexiBLAS build support per #64752 (#64815)

Summary:
To enable building torch+dependencies, set WITH_BLAS=flexi BLAS=FlexiBLAS

Fixes https://github.com/pytorch/pytorch/issues/64752

Pull Request resolved: https://github.com/pytorch/pytorch/pull/64815

Reviewed By: jbschlosser

Differential Revision: D31997745

Pulled By: albanD

fbshipit-source-id: db208d59002f5896608a03132616400f09d972aa

cmake/Dependencies.cmake

@@ -229,6 +229,10 @@ elseif(BLAS STREQUAL "vecLib")
   set(BLAS_INFO "veclib")
   set(BLAS_FOUND 1)
   set(BLAS_LIBRARIES ${vecLib_LINKER_LIBS})
+elseif(BLAS STREQUAL "FlexiBLAS")
+  find_package(FlexiBLAS REQUIRED)
+  include_directories(SYSTEM ${FlexiBLAS_INCLUDE_DIR})
+  list(APPEND Caffe2_PUBLIC_DEPENDENCY_LIBS ${FlexiBLAS_LIB})
 elseif(BLAS STREQUAL "Generic")
   # On Debian family, the CBLAS ABIs have been merged into libblas.so
   find_library(BLAS_LIBRARIES blas)
@@ -245,7 +249,7 @@ if(NOT INTERN_BUILD_MOBILE)
   set(AT_MKL_ENABLED 0)
   set(AT_MKL_MT 0)
   set(USE_BLAS 1)
-  if(NOT (ATLAS_FOUND OR BLIS_FOUND OR GENERIC_BLAS_FOUND OR MKL_FOUND OR OpenBLAS_FOUND OR VECLIB_FOUND))
+  if(NOT (ATLAS_FOUND OR BLIS_FOUND OR GENERIC_BLAS_FOUND OR MKL_FOUND OR OpenBLAS_FOUND OR VECLIB_FOUND OR FlexiBLAS_FOUND))
     message(WARNING "Preferred BLAS (" ${BLAS} ") cannot be found, now searching for a general BLAS library")
     find_package(BLAS)
     if(NOT BLAS_FOUND)

cmake/Modules/FindBLAS.cmake

@@ -152,6 +152,19 @@ if((NOT BLAS_LIBRARIES)
   endif()
 endif()
 
+if((NOT BLAS_LIBRARIES)
+    AND ((NOT WITH_BLAS) OR (WITH_BLAS STREQUAL "flexi")))
+  check_fortran_libraries(
+  BLAS_LIBRARIES
+  BLAS
+  sgemm
+  ""
+  "flexiblas")
+  if(BLAS_LIBRARIES)
+    set(BLAS_INFO "flexi")
+  endif(BLAS_LIBRARIES)
+endif()
+
 if((NOT BLAS_LIBRARIES)
     AND ((NOT WITH_BLAS) OR (WITH_BLAS STREQUAL "open")))
   check_fortran_libraries(

cmake/Modules/FindFlexiBLAS.cmake

@@ -0,0 +1,65 @@
+
+
+SET(Flexi_BLAS_INCLUDE_SEARCH_PATHS
+  /usr/include
+  /usr/include/flexiblas
+  /usr/include/flexiblas-base
+  /usr/local/include
+  /usr/local/include/flexiblas
+  /usr/local/include/flexiblas-base
+  /usr/local/opt/flexiblas/include
+  /opt/Flexiblas/include
+  $ENV{FlexiBLAS_HOME}
+  $ENV{FlexiBLAS_HOME}/include
+)
+
+SET(Flexi_BLAS_LIB_SEARCH_PATHS
+        /lib/
+        /lib/flexiblas-base
+        /lib64/
+        /usr/lib
+        /usr/lib/flexiblas-base
+        /usr/lib64
+        /usr/local/lib
+        /usr/local/lib64
+        /usr/local/opt/flexiblas/lib
+        /opt/FlexiBLAS/lib
+        $ENV{FlexiBLAS}
+        $ENV{FlexiBLAS}/lib
+        $ENV{FlexiBLAS_HOME}
+        $ENV{FlexiBLAS_HOME}/lib
+ )
+
+FIND_PATH(FlexiBLAS_INCLUDE_DIR NAMES cblas.h PATHS ${Flexi_BLAS_INCLUDE_SEARCH_PATHS})
+FIND_LIBRARY(FlexiBLAS_LIB NAMES flexiblas PATHS ${Flexi_BLAS_LIB_SEARCH_PATHS})
+
+SET(FlexiBLAS_FOUND ON)
+
+#    Check include files
+IF(NOT FlexiBLAS_INCLUDE_DIR)
+    SET(FlexiBLAS_FOUND OFF)
+    MESSAGE(STATUS "Could not find FlexiBLAS include. Turning FlexiBLAS_FOUND off")
+ENDIF()
+
+#    Check libraries
+IF(NOT FlexiBLAS_LIB)
+    SET(FlexiBLAS_FOUND OFF)
+    MESSAGE(STATUS "Could not find FlexiBLAS lib. Turning FlexiBLAS_FOUND off")
+ENDIF()
+
+IF (FlexiBLAS_FOUND)
+  IF (NOT FlexiBLAS_FIND_QUIETLY)
+    MESSAGE(STATUS "Found FlexiBLAS libraries: ${FlexiBLAS_LIB}")
+    MESSAGE(STATUS "Found FlexiBLAS include: ${FlexiBLAS_INCLUDE_DIR}")
+  ENDIF (NOT FlexiBLAS_FIND_QUIETLY)
+ELSE (FlexiBLAS_FOUND)
+  IF (FlexiBLAS_FIND_REQUIRED)
+    MESSAGE(FATAL_ERROR "Could not find FlexiBLAS")
+  ENDIF (FlexiBLAS_FIND_REQUIRED)
+ENDIF (FlexiBLAS_FOUND)
+
+MARK_AS_ADVANCED(
+    FlexiBLAS_INCLUDE_DIR
+    FlexiBLAS_LIB
+    FlexiBLAS
+)

cmake/Modules/FindLAPACK.cmake

@@ -119,6 +119,18 @@ if(BLAS_FOUND)
     endif()
   endif()
 
+  # FlexiBLAS
+  IF((NOT LAPACK_INFO) AND (BLAS_INFO STREQUAL "flexi"))
+    SET(CMAKE_REQUIRED_LIBRARIES ${BLAS_LIBRARIES})
+    check_function_exists("cheev_" FLEXIBLAS_LAPACK_WORKS)
+    set(CMAKE_REQUIRED_LIBRARIES)
+    if(FLEXIBLAS_LAPACK_WORKS)
+      SET(LAPACK_INFO "flexi")
+    else()
+      message(STATUS "Strangely, this FlexiBLAS library does not support Lapack?!")
+    endif()
+  endif()
+
   # OpenBlas
   IF((NOT LAPACK_INFO) AND (BLAS_INFO STREQUAL "open"))
     SET(CMAKE_REQUIRED_LIBRARIES ${BLAS_LIBRARIES})

setup.py

@@ -121,7 +121,7 @@
 #     one in this file; needed to build with other frameworks that share ONNX.
 #
 #   BLAS
-#     BLAS to be used by Caffe2. Can be MKL, Eigen, ATLAS, or OpenBLAS. If set
+#     BLAS to be used by Caffe2. Can be MKL, Eigen, ATLAS, FlexiBLAS, or OpenBLAS. If set
 #     then the build will fail if the requested BLAS is not found, otherwise
 #     the BLAS will be chosen based on what is found on your system.
 #