Replace CMake `iree_get_executable_path()` with `IMPORTED` targets. (#11764)
This changes how to access host tools during CMake's configure step from
using a custom `iree_get_executable_path()` function to using `IMPORTED`
targets
(https://cmake.org/cmake/help/latest/guide/importing-exporting/index.html).
A new helper `iree_import_binary` is added to keep
`IREE_HOST_BINARY_ROOT` use centralized.
## Details
Previously, each CMake file that wanted to use a tool that might be
provided by either the current build or a "host install" would use the
`iree_get_executable_path` function, e.g.
```cmake
# tools/CMakeLists.txt
if(IREE_BUILD_COMPILER)
iree_cc_binary(NAME iree-compile ...)
endif()
# some other file
iree_get_executable_path(_COMPILE_TOOL_EXECUTABLE "iree-compile")
add_custom_command(
OUTPUT ${_OUTPUT_FILES}
COMMAND ${_COMPILE_TOOL_EXECUTABLE} ${_ARGS}
DEPENDS ${_COMPILE_TOOL_EXECUTABLE} ${_SRC_PATH}
)
```
The `iree_get_executable_path` function attempted to find an executable
with that name and would add an `IMPORTED` target if one did not already
exist.
We can simplify that to just defining `IMPORTED` targets directly, right
where the targets are normally defined when `IREE_BUILD_COMPILER` is
enabled (or `CMAKE_CROSSCOMPILING` is disabled). Importing targets where
they are defined (rather than where they are used) will also let us more
cleanly solve issues like https://github.com/iree-org/iree/issues/11331.
Now this looks more like
```cmake
# tools/CMakeLists.txt
if(IREE_HOST_BINARY_ROOT AND NOT IREE_BUILD_COMPILER)
iree_import_binary(NAME iree-compile)
elseif(IREE_BUILD_COMPILER)
iree_cc_binary(NAME iree-compile ...)
else()
# warn about not building or importing
endif()
# some other file - use the target without caring if it was imported or not
add_custom_command(
OUTPUT ${_OUTPUT_FILES}
COMMAND iree-compile ${_ARGS}
DEPENDS iree-compile ${_SRC_PATH}
)
```
## Other context
This is an alternate take on https://github.com/iree-org/iree/pull/11441
and was discussed a bit here:
https://github.com/iree-org/iree/pull/11402#discussion_r1041471357.
Future PRs may
* Remove the implicit `bin/` suffix from `IREE_HOST_BINARY_ROOT` to
decouple it from the CMake `install` process
* Add `SHARED_LIBRARY_DEPS` to `iree_import_binary`, along with
`iree_import_library`, for proper dependency modeling of
IREECompiler.dll (assuming that `IMPORTED_RUNTIME_ARTIFACTS` doesn't
already do what I want)diff --git a/tools/CMakeLists.txt b/tools/CMakeLists.txt
index 82f188e..4d7cad6 100644
--- a/tools/CMakeLists.txt
+++ b/tools/CMakeLists.txt
@@ -11,34 +11,34 @@
# directory. Library targets and header files should be placed in the
# appropriate subtree, e.g. `compiler/src/iree/compiler/Tools/`.
#
-# Programs with a dependency on the compiler are not designed to run on device
-# platforms (e.g. Android), so they are tagged "hostonly".
+# Compiler tools are designed to run on host platforms (Linux, macOS, Windows),
+# so they are only built when IREE_BUILD_COMPILER is set and are tagged
+# "hostonly". When cross-compiling (or generally wanting to use already-built
+# compiler tools), set the IREE_HOST_BINARY_ROOT CMake option.
#
# This file does not use bazel_to_cmake because of special logic throughout.
+# Write some important CMake options to a file for convenient use from scripts.
+configure_file(build_config_template.txt.in build_config.txt)
+
+iree_add_all_subdirs()
+
+# TODO(scotttodd): Should this be checking IREE_BUILD_COMPILER?
+# Maybe we should disallow setting both at the same time, since it's
+# ambigious which should be used
+if(IREE_HOST_BINARY_ROOT AND NOT IREE_BUILD_COMPILER)
+ iree_import_binary(NAME iree-tblgen)
+ iree_import_binary(NAME iree-compile)
+ iree_import_binary(NAME iree-opt)
+ iree_import_binary(NAME iree-run-mlir)
+endif()
+
# TODO(#6353): Tools has thread dependencies in gtest, benchmark, yaml, etc.
# This should be split between runtime/compiler with optional threading support.
if(NOT IREE_ENABLE_THREADING)
return()
endif()
-# Write some important CMake options to a file for convenient use from scripts.
-configure_file(build_config_template.txt.in build_config.txt)
-
-# Depending on which target backends are enabled, we may or may not have built
-# LLD.
-if(IREE_LLD_TARGET)
- # lld install - required by the compiler to link codegen executables.
- install(
- TARGETS lld
- COMPONENT Compiler
- RUNTIME DESTINATION bin
- )
-endif()
-
-add_subdirectory(android)
-add_subdirectory(test)
-
iree_cc_binary(
NAME
iree-benchmark-module
@@ -172,6 +172,16 @@
)
if(IREE_BUILD_COMPILER)
+ # If a target backend that requires LLD to link codegen executables is
+ # enabled, install the target.
+ if(IREE_LLD_TARGET)
+ install(
+ TARGETS lld
+ COMPONENT Compiler
+ RUNTIME DESTINATION bin
+ )
+ endif()
+
iree_cc_binary(
NAME
iree-tblgen
@@ -282,4 +292,9 @@
DESTINATION "tests/bin"
COMPONENT Tests
)
-endif(IREE_BUILD_COMPILER)
+elseif(NOT DEFINED IREE_HOST_BINARY_ROOT)
+ message(STATUS
+ "*Not* building or importing IREE's compiler tools.\n "
+ "Set IREE_BUILD_COMPILER to build them or IREE_HOST_BINARY_ROOT to "
+ "import them.")
+endif()
