Only include lapack when necessary

Makefile

@@ -211,10 +211,6 @@ $(LZ4LIB):
 	make -C lz4
 
 
-something:
-	cd packages/scipy/build/scipy-0.17.1 && emcc -O3 -s BINARYEN_METHOD=native-wasm -Werror -s EMULATED_FUNCTION_POINTERS=1 -s EMULATE_FUNCTION_POINTER_CASTS=1 -s SIDE_MODULE=1 -s WASM=1 -s BINARYEN_TRAP_MODE=clamp --memory-init-file 0 -Wall -g -Wall -g -shared build/temp.linux-x86_64-3.7/build/src.linux-x86_64-3.7/build/src.linux-x86_64-3.7/scipy/linalg/_fblasmodule.bc build/temp.linux-x86_64-3.7/build/src.linux-x86_64-3.7/build/src.linux-x86_64-3.7/build/src.linux-x86_64-3.7/scipy/linalg/fortranobject.bc build/temp.linux-x86_64-3.7/src/packages/scipy/build/scipy-0.17.1/scipy/_build_utils/src/wrap_dummy_g77_abi.bc build/temp.linux-x86_64-3.7/src/packages/scipy/build/scipy-0.17.1/scipy/_build_utils/src/wrap_dummy_accelerate.bc build/temp.linux-x86_64-3.7/build/src.linux-x86_64-3.7/build/src.linux-x86_64-3.7/scipy/linalg/_fblas-f2pywrappers.bc ../../../../CLAPACK-WA/F2CLIBS/libf2c.bc -lblas_WA -llapack_WA -disable-verify -Lbuild/temp.linux-x86_64-3.7 -lgfortran -o build/lib.linux-x86_64-3.7/scipy/linalg/_fblas.cpython-37m-x86_64-linux-gnu.wasm
-
-
 $(SIX_LIBS): $(CPYTHONLIB)
 	make -C six
 

pyodide_build/pywasmcross.py

@@ -238,6 +238,7 @@ def handle_command(line, args, dryrun=False):
 
     lapack_dir = None
 
+    # rebuild = False
     # Go through and adjust arguments
     for arg in line[1:]:
         if arg.startswith('-I'):
@@ -259,12 +260,31 @@ def handle_command(line, args, dryrun=False):
         elif shared and arg.endswith('.so'):
             arg = arg[:-3] + '.wasm'
             output = arg
+
         # Fix for scipy to link to the correct BLAS/LAPACK files
         if arg.startswith('-L') and 'CLAPACK-WA' in arg:
+            # rebuild = True
+            out_idx = line.index('-o')
+            out_idx += 1
+            module_name = line[out_idx]
+            module_name = Path(module_name).name.split('.')[0]
+
+            if module_name not in ['_fblas', '_flapack', '_flinalg',
+                                   '_calc_lwork', 'cython_blas',
+                                   'cython_lapack', '_iterative',
+                                   '_arpack']:
+                raise ValueError(f"Unsupported module requiring BLAS/LAPACK "
+                                 f"{module_name} in {' '.join(line)}")
+
             lapack_dir = arg.replace('-L', '')
-            for lib_name in ['F2CLIBS/libf2c.bc',
-                             'blas_WA.bc',
-                             'lapack_WA.bc']:
+            # For convinience we determine needed scipy link libraries
+            # here, instead of in patch files
+            link_libs = ['F2CLIBS/libf2c.bc', 'blas_WA.bc']
+            if module_name in ['_flapack', '_flinalg', '_calc_lwork',
+                               'cython_lapack', '_iterative', '_arpack']:
+                link_libs.append('lapack_WA.bc')
+
+            for lib_name in link_libs:
                 arg = os.path.join(lapack_dir, f"{lib_name}")
                 new_args.append(arg)
             continue
@@ -273,7 +293,7 @@ def handle_command(line, args, dryrun=False):
 
     # This can only be used for incremental rebuilds -- it generates
     # an error during clean build of numpy
-    # if os.path.isfile(output):
+    # if os.path.isfile(output) and not rebuild:
     #     print('SKIPPING: ' + ' '.join(new_args))
     #     return
 
@@ -329,10 +349,10 @@ def install_for_distribution(args):
     try:
         subprocess.check_call(commands)
     except Exception:
-        print(f'Warning: {" ".join(commands)} failed with distutils, possibly '
-              f'due to the use of distutils that does not support the '
-              f'--old-and-unmanageable argument. Re-trying the install '
-              f'without this argument.')
+        print(f'Warning: {" ".join(str(arg) for arg in commands)} failed '
+              f'with distutils, possibly due to the use of distutils '
+              f'that does not support the --old-and-unmanageable '
+              'argument. Re-trying the install without this argument.')
         subprocess.check_call(commands[:-1])