support aarch64 on Windows

Adapted from a patch shared by Tomas Kalibera.

Author: kevinushey

R/tbb.R

@@ -81,6 +81,10 @@ tbbLdFlags <- function() {
 return(sprintf(fmt, asBuildPath(tbbLib)))
  }
 
+# on Aarch64 builds, use the version of TBB provided by Rtools
+if (is_windows() &&R.version$arch=="aarch64")
+return("-ltbb12 -ltbbmalloc")
+
 # on Mac, Windows and Solaris, we need to explicitly link (#206)
 needsExplicitFlags<- is_mac() || is_windows() || (is_solaris() &&!is_sparc())
 if (needsExplicitFlags) {

R/zzz.R

@@ -27,8 +27,12 @@ loadTbbLibrary <- function(name) {
 
 .onLoad<-function(libname, pkgname) {
 
+tbbLibraryName<-"tbb"
+if (is_windows() &&R.version$arch=="aarch64")
+tbbLibraryName<-"tbb12"
+
 # load tbb, tbbmalloc
-.tbbDllInfo<<- loadTbbLibrary("tbb")
+.tbbDllInfo<<- loadTbbLibrary(tbbLibraryName)
 .tbbMallocDllInfo<<- loadTbbLibrary("tbbmalloc")
 
 # load tbbmalloc_proxy, but only if requested

src/Makevars.in

@@ -88,6 +88,14 @@ ifeq ($(USE_TBB), Windows)
  # Linker needs access to the tbb dll; otherwise you get errors such as:
  # "undefined reference to `tbb::task_scheduler_init::terminate()'"
  PKG_LIBS += -Ltbb/build/lib_release -ltbb -ltbbmalloc
+
+ # override for aarch64 (experimental) to use Rtools TBB
+ ARCH=$(shell "${R_HOME}/bin/R" --vanilla -s -e 'cat(R.version$$arch)')
+ ifeq "$(ARCH)" "aarch64"
+ TBB_LIB = ${R_TOOLS_SOFT}
+ TBB_INC = ${R_TOOLS_SOFT}
+ PKG_LIBS = -ltbb12 -ltbbmalloc
+ endif
 
 endif