do not rely on CMakeLists.txt in isl submodule

Mainline isl uses autoconf/automake as a build system.
The isl submodule used by TC is a heavily modified version of isl and
also supports cmake.
Reducing the difference and keeping up with changes in mainline isl
occasionally requires changes to the build system configuration files.
Having to perform the changes for both systems at the same time
while merging is a needless additional complication.
Support for cmake will therefore be removed from the modified version and
TC can no longer rely on this support.

There are at least two ways of handling the removal of cmake support
from the isl submodule.  The isl submodule could be configured
as a cmake "external project" or the isl files can simply be
compiled in directly.  This commits opts for the second option
based on the assumption that an external project will be more
difficult to handle on Windows systems.
Note that this commit also hard-codes some options that will
not work on Windows, but setting these options correctly
should not be too difficult for someone familiar with cmake.

Note that if any source files get added to isl, then
the local CMakeLists.txt still needs to get updated, but this
can be done while updating the submodule and after the merge
has been completed.

The build files are stored in "external/isl", even though
the object files are part of tc_core, because the source files
live in third-party/islpp.
They are not stored in "tc/external" because they involve extra files
that are private to the (locally built) isl library, while "tc/external"
contains the public interface to isl (within TC).
It may make sense to move the contents of "tc/external" somewhere else,
but that is a different issue.

Author: Sven Verdoolaege

CMakeLists.txt

@@ -226,13 +226,11 @@ message(STATUS "Found ATen.so file: ${ATEN_LIBRARIES}")
 ################################################################################
 # isl
 ################################################################################
-set(ISL_INT "gmp" CACHE STRING "Which package to use to represent multi-precision integers (gmp|imath)")
 # use locally generated C++ bindings
 include_directories(AFTER ${PROJECT_SOURCE_DIR}/isl_interface/include)
 include_directories(AFTER ${PROJECT_SOURCE_DIR}/third-party/islpp/include)
 include_directories(AFTER ${CMAKE_CURRENT_BINARY_DIR}/third-party/islpp/include)
-add_subdirectory(third-party/islpp)
-set(ISL_LIBRARIES isl-static)
+add_subdirectory(external/isl)
 
 ################################################################################
 # Halide

external/isl/CMakeLists.txt

@@ -0,0 +1,109 @@
+find_path(GMP_INCLUDE_DIR gmp.h)
+find_library(GMP_LIBRARY NAMES gmp)
+
+set(ISL_SOURCE_DIR "${PROJECT_SOURCE_DIR}/third-party/islpp")
+
+set(ISL_SOURCES
+    ${ISL_SOURCE_DIR}/basis_reduction_tab.c
+    ${ISL_SOURCE_DIR}/isl_aff.c
+    ${ISL_SOURCE_DIR}/isl_aff_map.c
+    ${ISL_SOURCE_DIR}/isl_affine_hull.c
+    ${ISL_SOURCE_DIR}/isl_arg.c
+    ${ISL_SOURCE_DIR}/isl_ast_build.c
+    ${ISL_SOURCE_DIR}/isl_ast_build_expr.c
+    ${ISL_SOURCE_DIR}/isl_ast.c
+    ${ISL_SOURCE_DIR}/isl_ast_codegen.c
+    ${ISL_SOURCE_DIR}/isl_ast_graft.c
+    ${ISL_SOURCE_DIR}/isl_bernstein.c
+    ${ISL_SOURCE_DIR}/isl_blk.c
+    ${ISL_SOURCE_DIR}/isl_bound.c
+    ${ISL_SOURCE_DIR}/isl_box.c
+    ${ISL_SOURCE_DIR}/isl_coalesce.c
+    ${ISL_SOURCE_DIR}/isl_constraint.c
+    ${ISL_SOURCE_DIR}/isl_convex_hull.c
+    ${ISL_SOURCE_DIR}/isl_ctx.c
+    ${ISL_SOURCE_DIR}/isl_deprecated.c
+    ${ISL_SOURCE_DIR}/isl_dim_map.c
+    ${ISL_SOURCE_DIR}/isl_equalities.c
+    ${ISL_SOURCE_DIR}/isl_factorization.c
+    ${ISL_SOURCE_DIR}/isl_farkas.c
+    ${ISL_SOURCE_DIR}/isl_ffs.c
+    ${ISL_SOURCE_DIR}/isl_flow.c
+    ${ISL_SOURCE_DIR}/isl_fold.c
+    ${ISL_SOURCE_DIR}/isl_hash.c
+    ${ISL_SOURCE_DIR}/isl_id.c
+    ${ISL_SOURCE_DIR}/isl_id_to_ast_expr.c
+    ${ISL_SOURCE_DIR}/isl_id_to_id.c
+    ${ISL_SOURCE_DIR}/isl_id_to_pw_aff.c
+    ${ISL_SOURCE_DIR}/isl_ilp.c
+    ${ISL_SOURCE_DIR}/isl_input.c
+    ${ISL_SOURCE_DIR}/isl_local.c
+    ${ISL_SOURCE_DIR}/isl_local_space.c
+    ${ISL_SOURCE_DIR}/isl_lp.c
+    ${ISL_SOURCE_DIR}/isl_map.c
+    ${ISL_SOURCE_DIR}/isl_map_list.c
+    ${ISL_SOURCE_DIR}/isl_map_simplify.c
+    ${ISL_SOURCE_DIR}/isl_map_subtract.c
+    ${ISL_SOURCE_DIR}/isl_map_to_basic_set.c
+    ${ISL_SOURCE_DIR}/isl_mat.c
+    ${ISL_SOURCE_DIR}/isl_morph.c
+    ${ISL_SOURCE_DIR}/isl_obj.c
+    ${ISL_SOURCE_DIR}/isl_options.c
+    ${ISL_SOURCE_DIR}/isl_output.c
+    ${ISL_SOURCE_DIR}/isl_point.c
+    ${ISL_SOURCE_DIR}/isl_polynomial.c
+    ${ISL_SOURCE_DIR}/isl_printer.c
+    ${ISL_SOURCE_DIR}/isl_range.c
+    ${ISL_SOURCE_DIR}/isl_reordering.c
+    ${ISL_SOURCE_DIR}/isl_sample.c
+    ${ISL_SOURCE_DIR}/isl_scan.c
+    ${ISL_SOURCE_DIR}/isl_schedule.c
+    ${ISL_SOURCE_DIR}/isl_schedule_band.c
+    ${ISL_SOURCE_DIR}/isl_schedule_node.c
+    ${ISL_SOURCE_DIR}/isl_schedule_read.c
+    ${ISL_SOURCE_DIR}/isl_schedule_tree.c
+    ${ISL_SOURCE_DIR}/isl_scheduler.c
+    ${ISL_SOURCE_DIR}/isl_schedule_constraints.c
+    ${ISL_SOURCE_DIR}/isl_seq.c
+    ${ISL_SOURCE_DIR}/isl_set_list.c
+    ${ISL_SOURCE_DIR}/isl_sort.c
+    ${ISL_SOURCE_DIR}/isl_space.c
+    ${ISL_SOURCE_DIR}/isl_stream.c
+    ${ISL_SOURCE_DIR}/isl_stride.c
+    ${ISL_SOURCE_DIR}/isl_tab.c
+    ${ISL_SOURCE_DIR}/isl_tab_pip.c
+    ${ISL_SOURCE_DIR}/isl_tarjan.c
+    ${ISL_SOURCE_DIR}/isl_transitive_closure.c
+    ${ISL_SOURCE_DIR}/isl_union_map.c
+    ${ISL_SOURCE_DIR}/isl_val.c
+    ${ISL_SOURCE_DIR}/isl_vec.c
+    ${ISL_SOURCE_DIR}/isl_version.c
+    ${ISL_SOURCE_DIR}/isl_vertices.c
+    ${ISL_SOURCE_DIR}/print.c
+    ${ISL_SOURCE_DIR}/isl_gmp.c
+    ${ISL_SOURCE_DIR}/isl_val_gmp.c
+)
+
+# The tc_isl library is included in the (shared) tc_core library.
+add_library(tc_isl STATIC)
+set_property(TARGET tc_isl PROPERTY POSITION_INDEPENDENT_CODE ON)
+target_include_directories(
+  tc_isl
+  PRIVATE
+  ${PROJECT_SOURCE_DIR}/third-party/islpp
+  ${CMAKE_CURRENT_SOURCE_DIR}
+  ${CMAKE_CURRENT_BINARY_DIR}
+  ${GMP_INCLUDE_DIR}
+)
+target_sources(tc_isl PRIVATE ${ISL_SOURCES})
+target_link_libraries(tc_isl ${GMP_LIBRARY})
+
+# The following sets "gitversion.h" only at configure time.
+# Since TC currently does not call isl_version(),
+# it is not worth it to try and be more accurate.
+execute_process(
+  COMMAND ${GIT_EXECUTABLE} describe
+  WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}/third-party/islpp
+  OUTPUT_VARIABLE ISL_GIT_VERSION
+  OUTPUT_STRIP_TRAILING_WHITESPACE)
+configure_file("gitversion.h.in" "gitversion.h")

external/isl/gitversion.h.in

@@ -0,0 +1 @@
+#define GIT_HEAD_ID "${ISL_GIT_VERSION}"

external/isl/isl_config.h

@@ -0,0 +1,24 @@
+/* Hard-coded configuration variables. */
+
+/* define if your compiler has __attribute__ */
+#define HAVE___ATTRIBUTE__ /**/
+
+/* Define to 1 if you have the declaration of `ffs', and to 0 if you don't. */
+#define HAVE_DECL_FFS 1
+
+/* Define to 1 if you have the declaration of `strcasecmp', and to 0 if you
+   don't. */
+#define HAVE_DECL_STRCASECMP 1
+
+/* Define to 1 if you have the declaration of `strncasecmp', and to 0 if you
+   don't. */
+#define HAVE_DECL_STRNCASECMP 1
+
+/* Define to 1 if you have the declaration of `snprintf', and to 0 if you
+   don't. */
+#define HAVE_DECL_SNPRINTF 1
+
+/* use gmp to implement isl_int */
+#define USE_GMP_FOR_MP
+
+#include <isl_config_post.h>

tc/core/CMakeLists.txt

@@ -43,9 +43,9 @@ target_link_libraries(
   glog
 
   ${HALIDE_LIBRARIES}
-  ${ISL_LIBRARIES}
   -lLLVM
 
+  tc_isl
   tc_lang
   tc_version
   tc_proto
@@ -82,7 +82,6 @@ target_link_libraries(
   tc_core_cpu
 
   ${HALIDE_LIBRARIES}
-  ${ISL_LIBRARIES}
   -lLLVM
 
   tc_lang
@@ -129,7 +128,6 @@ target_link_libraries(
   tc_core_cuda_no_sdk
 
   ${HALIDE_LIBRARIES}
-  ${ISL_LIBRARIES}
   -lLLVM
 
   tc_lang
@@ -174,7 +172,6 @@ if (WITH_CUDA)
     ${CUDA_curand_LIBRARY}
     ${CUDA_LIBRARIES}
     ${CUDA_NVRTC_LIBRARIES}
-    ${ISL_LIBRARIES}
 
     tc_lang
     tc_version