cmake: Add CK_PARALLEL_LINK_JOBS and CK_PARALLEL_COMPILE_JOBS options (#1063)

Copied from the llvm-project LLVM_PARALLEL_*_JOBS

Concurrent linking can break the build as well as having too many
compile jobs for the avaiable memory.  These options allow the user
to fine tune the build to fit within their machines memory
constraints.

An example use on linux is
COMPILE_JOBS=`cat /proc/cpuinfo | grep -m 1 'cpu cores' | awk '{ print $4 }'`
if [ ${COMPILE_JOBS}x = x ]; then
  COMPILE_JOBS=1
fi
BUILD_MEM=4
MEM_KB=0
MEM_KB=`cat /proc/meminfo | grep MemTotal | awk '{ print $2 }'`
MEM_MB=`eval "expr ${MEM_KB} / 1024"`
MEM_GB=`eval "expr ${MEM_MB} / 1024"`
COMPILE_JOBS_MEM=`eval "expr 1 + ${MEM_GB} / ${BUILD_MEM}"`
if [ "$COMPILE_JOBS_MEM" -lt "$COMPILE_JOBS" ]; then
  COMPILE_JOBS=$COMPILE_JOBS_MEM
fi
LINK_MEM=32
LINK_JOBS=`eval "expr 1 + ${MEM_GB} / ${LINK_MEM}"`

cmake -G Ninja -DCK_PARALLEL_LINK_JOBS=$LINK_JOBS
               -DCK_PARALLEL_COMPILE_JOBS=$COMPILE_JOBS
Signed-off-by: Tom Rix <trix@redhat.com>

CMakeLists.txt

@@ -146,6 +146,33 @@ if(${hip_VERSION_FLAT} GREATER 500723302)
    add_compile_options(-fno-offload-uniform-block)
 endif()
 
+#
+# Seperate linking jobs from compiling
+# Too many concurrent linking jobs can break the build
+# Copied from LLVM
+set(CK_PARALLEL_LINK_JOBS "" CACHE STRING
+  "Define the maximum number of concurrent link jobs (Ninja only).")
+if(CMAKE_GENERATOR MATCHES "Ninja")
+  if(CK_PARALLEL_LINK_JOBS)
+    set_property(GLOBAL APPEND PROPERTY JOB_POOLS link_job_pool=${CK_PARALLEL_LINK_JOBS})
+    set(CMAKE_JOB_POOL_LINK link_job_pool)
+  endif()
+elseif(CK_PARALLEL_LINK_JOBS)
+  message(WARNING "Job pooling is only available with Ninja generators.")
+endif()
+# Similar for compiling
+set(CK_PARALLEL_COMPILE_JOBS "" CACHE STRING
+  "Define the maximum number of concurrent compile jobs (Ninja only).")
+if(CMAKE_GENERATOR MATCHES "Ninja")
+  if(CK_PARALLEL_COMPILE_JOBS)
+    set_property(GLOBAL APPEND PROPERTY JOB_POOLS compile_job_pool=${CK_PARALLEL_COMPILE_JOBS})
+    set(CMAKE_JOB_POOL_COMPILE compile_job_pool)
+  endif()
+elseif(CK_PARALLEL_COMPILE_JOBS)
+  message(WARNING "Job pooling is only available with Ninja generators.")
+endif()
+
+
 option(USE_BITINT_EXTENSION_INT4, "Whether to enable clang's BitInt extension to provide int4 data type." OFF)
 option(USE_OPT_NAVI3X, "Whether to enable LDS cumode and Wavefront32 mode for NAVI3X silicons." OFF)