[libclc] [libclc] Fix building top-level 'libclc' target (PR #150972)

[Fraser Cormack via cfe-commits]

https://github.com/frasercrmck created https://github.com/llvm/llvm-project/pull/150972

With libclc being a 'runtime', the top-level build assumes that there is a corresopnding 'libclc' target. We previously weren't providing this, leading to a build failure if the user tried to build it.

This commit remedies this by adding support for building the 'libclc' target. It does so by adding dependencies from the OpenCL builtins to this target. It uses a configurable in-between target - libclc-opencl-builtins - to ease the possibility of adding non-OpenCL builtin libraries in the future.

>From d08c5dea1b8ee797c27869e436b24b85a2d285bc Mon Sep 17 00:00:00 2001
From: Fraser Cormack <fraser at codeplay.com>
Date: Mon, 28 Jul 2025 15:57:11 +0100
Subject: [PATCH] [libclc] Fix building top-level 'libclc' target

With libclc being a 'runtime', the top-level build assumes that there is
a corresopnding 'libclc' target. We previously weren't providing this,
leading to a build failure if the user tried to build it.

This commit remedies this by adding support for building the 'libclc'
target. It does so by adding dependencies from the OpenCL builtins to
this target. It uses a configurable in-between target -
libclc-opencl-builtins - to ease the possibility of adding non-OpenCL
builtin libraries in the future.
---
 libclc/CMakeLists.txt                | 7 +++++++
 libclc/cmake/modules/AddLibclc.cmake | 8 +++++++-
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/libclc/CMakeLists.txt b/libclc/CMakeLists.txt
index e4e9a74639b17..c98e6880b52ce 100644
--- a/libclc/CMakeLists.txt
+++ b/libclc/CMakeLists.txt
@@ -5,6 +5,9 @@ if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
 endif()
 set(LLVM_SUBPROJECT_TITLE "libclc")
 
+# Top level target used to build all Libclc libraries.
+add_custom_target( libclc ALL )
+
 set(CMAKE_CXX_STANDARD 17)
 
 # Add path for custom modules
@@ -42,6 +45,9 @@ set( LIBCLC_TARGETS_TO_BUILD "all"
 
 option( ENABLE_RUNTIME_SUBNORMAL "Enable runtime linking of subnormal support." OFF )
 
+add_custom_target( libclc-opencl-builtins COMMENT "Build libclc OpenCL builtins" )
+add_dependencies( libclc libclc-opencl-builtins )
+
 if( LIBCLC_STANDALONE_BUILD OR CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR )
   # Out-of-tree configuration
   set( LIBCLC_STANDALONE_BUILD TRUE )
@@ -463,6 +469,7 @@ foreach( t ${LIBCLC_TARGETS_TO_BUILD} )
       LIB_FILES ${opencl_lib_files}
       GEN_FILES ${opencl_gen_files}
       ALIASES ${${d}_aliases}
+      PARENT_TARGET libclc-opencl-builtins
       # Link in the CLC builtins and internalize their symbols
       INTERNAL_LINK_DEPENDENCIES builtins.link.clc-${arch_suffix}
     )
diff --git a/libclc/cmake/modules/AddLibclc.cmake b/libclc/cmake/modules/AddLibclc.cmake
index dc4b1e8286ec0..9b0e5d99b5826 100644
--- a/libclc/cmake/modules/AddLibclc.cmake
+++ b/libclc/cmake/modules/AddLibclc.cmake
@@ -207,6 +207,8 @@ endfunction()
 #      libclc architecture/triple suffix
 #  * TRIPLE <string>
 #      Triple used to compile
+#  * PARENT_TARGET <string>
+#      Target into which to group the target builtins
 #
 # Optional Arguments:
 # * CLC_INTERNAL
@@ -229,7 +231,7 @@ endfunction()
 function(add_libclc_builtin_set)
   cmake_parse_arguments(ARG
     "CLC_INTERNAL"
-    "ARCH;TRIPLE;ARCH_SUFFIX"
+    "ARCH;TRIPLE;ARCH_SUFFIX;PARENT_TARGET"
     "LIB_FILES;GEN_FILES;COMPILE_FLAGS;OPT_FLAGS;ALIASES;INTERNAL_LINK_DEPENDENCIES"
     ${ARGN}
   )
@@ -403,6 +405,9 @@ function(add_libclc_builtin_set)
     add_custom_target( prepare-${ARG_TRIPLE} ALL )
   endif()
   add_dependencies( prepare-${ARG_TRIPLE} prepare-${obj_suffix} )
+  # Add dependency to top-level pseudo target to ease making other
+  # targets dependent on libclc.
+  add_dependencies( ${ARG_PARENT_TARGET} prepare-${ARG_TRIPLE} )
 
   install(
     FILES ${libclc_builtins_lib}
@@ -445,6 +450,7 @@ function(add_libclc_builtin_set)
     add_custom_target( alias-${alias_suffix} ALL
       DEPENDS ${LIBCLC_OUTPUT_LIBRARY_DIR}/${alias_suffix}
     )
+    add_dependencies( ${ARG_PARENT_TARGET} alias-${alias_suffix} )
     set_target_properties( alias-${alias_suffix}
       PROPERTIES FOLDER "libclc/Device IR/Aliases"
     )