sys-devel/llvm: Backport tensorflow automagic dep fix

Backport patch fixing CMakeLists.txt not to use tensorflow
automagically.  This also fixes build failure due to our TF packages
being incompatible.  TF is now always-off.

Thanks to Georgy Yakovlev for rebasing and testing the patch.

Closes: https://bugs.gentoo.org/748444
Signed-off-by: Michał Górny <mgorny@gentoo.org>

2 files changed, 61 insertions, 0 deletions

diff --git a/sys-devel/llvm/files/11.0.0/0001-backport-D88371-guard-find_library-tensorflow_c_api.patch b/sys-devel/llvm/files/11.0.0/0001-backport-D88371-guard-find_library-tensorflow_c_api.patch
new file mode 100644
index 000000000000..73959afb2677
--- /dev/null
+++ b/sys-devel/llvm/files/11.0.0/0001-backport-D88371-guard-find_library-tensorflow_c_api.patch
@@ -0,0 +1,55 @@
+From 8dcb88f7705fb3927938dd9bd103efcabafcefb0 Mon Sep 17 00:00:00 2001
+From: Georgy Yakovlev <gyakovlev@gentoo.org>
+Date: Tue, 27 Oct 2020 18:20:56 -0700
+Subject: [PATCH] backport D88371, guard `find_library(tensorflow_c_api ...)`
+
+Differential Revision: https://reviews.llvm.org/D88371
+Signed-off-by: Georgy Yakovlev <gyakovlev@gentoo.org>
+---
+ llvm/CMakeLists.txt | 15 +++++++--------
+ 1 file changed, 7 insertions(+), 8 deletions(-)
+
+diff --git a/llvm/CMakeLists.txt b/llvm/CMakeLists.txt
+index 1f137f0..4112def 100644
+--- a/llvm/CMakeLists.txt
++++ b/llvm/CMakeLists.txt
+@@ -832,6 +832,11 @@ configure_file(
+   ${LLVM_INCLUDE_DIR}/llvm/Config/Targets.def
+   )
+ 
++# They are not referenced. See set_output_directory().
++set( CMAKE_RUNTIME_OUTPUT_DIRECTORY ${LLVM_BINARY_DIR}/bin )
++set( CMAKE_LIBRARY_OUTPUT_DIRECTORY ${LLVM_BINARY_DIR}/lib${LLVM_LIBDIR_SUFFIX} )
++set( CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${LLVM_BINARY_DIR}/lib${LLVM_LIBDIR_SUFFIX} )
++
+ # For up-to-date instructions for installing the Tensorflow dependency, refer to
+ # the bot setup script: https://github.com/google/ml-compiler-opt/blob/master/buildbot/buildbot_init.sh
+ # In this case, the latest C API library is available for download from
+@@ -840,9 +845,9 @@ configure_file(
+ # LLVM_HAVE_TF_API, through llvm-config.h, so that a user of the LLVM library may
+ # also leverage the dependency.
+ set(TENSORFLOW_C_LIB_PATH "" CACHE PATH "Path to TensorFlow C library install")
+-find_library(tensorflow_c_api tensorflow PATHS ${TENSORFLOW_C_LIB_PATH}/lib)
+ 
+-if (tensorflow_c_api)
++if (TENSORFLOW_C_LIB_PATH)
++  find_library(tensorflow_c_api tensorflow PATHS ${TENSORFLOW_C_LIB_PATH}/lib NO_DEFAULT_PATH REQUIRED)
+   set(LLVM_HAVE_TF_API "ON" CACHE BOOL "Full Tensorflow API available")
+   include_directories(${TENSORFLOW_C_LIB_PATH}/include)
+ endif()
+@@ -877,12 +882,6 @@ add_custom_target(srpm
+   COMMAND rpmbuild -bs --define '_topdir ${LLVM_SRPM_DIR}' ${LLVM_SRPM_BINARY_SPECFILE})
+ set_target_properties(srpm PROPERTIES FOLDER "Misc")
+ 
+-
+-# They are not referenced. See set_output_directory().
+-set( CMAKE_RUNTIME_OUTPUT_DIRECTORY ${LLVM_BINARY_DIR}/bin )
+-set( CMAKE_LIBRARY_OUTPUT_DIRECTORY ${LLVM_BINARY_DIR}/lib${LLVM_LIBDIR_SUFFIX} )
+-set( CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${LLVM_BINARY_DIR}/lib${LLVM_LIBDIR_SUFFIX} )
+-
+ if(APPLE AND DARWIN_LTO_LIBRARY)
+   set(CMAKE_EXE_LINKER_FLAGS
+     "${CMAKE_EXE_LINKER_FLAGS} -Wl,-lto_library -Wl,${DARWIN_LTO_LIBRARY}")
+-- 
+2.26.2
+
diff --git a/sys-devel/llvm/llvm-11.0.0.ebuild b/sys-devel/llvm/llvm-11.0.0.ebuild
index 6bdf1c7ec770..ad20115fb6bf 100644
--- a/sys-devel/llvm/llvm-11.0.0.ebuild
+++ b/sys-devel/llvm/llvm-11.0.0.ebuild
@@ -73,6 +73,12 @@ RDEPEND="${RDEPEND}
 PDEPEND="sys-devel/llvm-common
 	gold? ( >=sys-devel/llvmgold-${SLOT} )"
 
+PATCHES=(
+	# backport tensorflow finding fix (avoids broken automagic dep)
+	# https://bugs.gentoo.org/748444
+	"${FILESDIR}"/11.0.0/0001-backport-D88371-guard-find_library-tensorflow_c_api.patch
+)
+
 python_check_deps() {
 	use doc || return 0