Fix aligned allocation for old macOS targets

NEWS.md

@@ -1,5 +1,9 @@
 # RcppParallel (development version)
 
+* Fixed bundled oneTBB builds and downstream compilation with Clang and libc++
+  when targeting macOS 10.12 or earlier, where C++17 aligned allocation is not
+  available. (#219)
+
 
 # RcppParallel 6.2.0
 

R/tbb-autodetected.R.in

@@ -2,6 +2,7 @@
 TBB_ENABLED <- @TBB_ENABLED@
 TBB_LIB  <- "@TBB_LIB@"
 TBB_INC  <- "@TBB_INC@"
+TBB_CXXFLAGS <- "@TBB_CXXFLAGS@"
 
 TBB_NAME <- "@TBB_NAME@"
-TBB_MALLOC_NAME <- "@TBB_MALLOC_NAME@"
+TBB_MALLOC_NAME <- "@TBB_MALLOC_NAME@"

R/tbb.R

@@ -57,6 +57,9 @@ tbbCxxFlags <- function() {
 
    flags <- c("-DRCPP_PARALLEL_USE_TBB=1")
 
+   if (nzchar(TBB_CXXFLAGS))
+      flags <- c(flags, TBB_CXXFLAGS)
+
    # if TBB_INC is set, apply those library paths
    tbbInc <- Sys.getenv("TBB_INC", unset = TBB_INC)
    if (!file.exists(tbbInc)) {

src/Makevars.in

@@ -10,6 +10,7 @@ TBB_LIB         = @TBB_LIB@
 TBB_INC         = @TBB_INC@
 TBB_NAME        = @TBB_NAME@
 TBB_MALLOC_NAME = @TBB_MALLOC_NAME@
+TBB_CXXFLAGS    = @TBB_CXXFLAGS@
 
 PKG_CPPFLAGS = @PKG_CPPFLAGS@
 PKG_CXXFLAGS = @PKG_CXXFLAGS@
@@ -28,7 +29,8 @@ tbb: tbb-clean
 	@TBB_LIB="$(TBB_LIB)" TBB_INC="$(TBB_INC)"                  \
 	TBB_NAME="$(TBB_NAME)" TBB_MALLOC_NAME="$(TBB_MALLOC_NAME)" \
 	CC="$(CC)" CFLAGS="$(CFLAGS)" CPPFLAGS="$(CPPFLAGS)"        \
-	CXX="$(CXX)" CXXFLAGS="$(CXXFLAGS)"	LDFLAGS="$(LDFLAGS)"    \
+	CXX="$(CXX)" CXXFLAGS="$(CXXFLAGS) $(TBB_CXXFLAGS)"         \
+	LDFLAGS="$(LDFLAGS)"                                        \
 	CMAKE="$(CMAKE)" "@R@" -s -f install.libs.R --args build
 
 # NOTE: we do not want to clean ../inst/lib or ../inst/libs here,

tests/test-cxx-flags.R

@@ -0,0 +1,18 @@
+# Unit tests for the compiler flags handed to downstream packages through
+# RcppParallel::CxxFlags().
+
+RcppParallel:::test_init()
+
+flags <- tbbCxxFlags()
+
+assert(is.character(flags))
+assert(length(flags) == 1L)
+assert(!is.na(flags))
+assert(grepl("-DRCPP_PARALLEL_USE_TBB=1", flags, fixed = TRUE))
+
+hasNoAlignedAllocation <- grepl(
+   "-fno-aligned-allocation",
+   flags,
+   fixed = TRUE
+)
+assert(identical(hasNoAlignedAllocation, nzchar(TBB_CXXFLAGS)))

tools/config/configure.R

@@ -1,7 +1,46 @@
 
 # make sure we call correct version of R
 rExe <- if (.Platform$OS.type == "windows") "R.exe" else "R"
-define(R = file.path(R.home("bin"), rExe))
+rPath <- file.path(R.home("bin"), rExe)
+define(R = rPath)
+
+# Clang enables C++17 aligned allocation based on the deployment target, but
+# the corresponding libc++ entry points are unavailable before macOS 10.13.
+# Probe through R CMD SHLIB so we see the compiler, standard library, flags,
+# launchers, and user Makevars settings that will actually build the package.
+tbbNeedsNoAlignedAllocation <- function() {
+
+   if (!identical(Sys.info()[["sysname"]], "Darwin"))
+      return(FALSE)
+
+   probeDir <- tempfile("RcppParallel-configure-")
+   dir.create(probeDir)
+   on.exit(unlink(probeDir, recursive = TRUE), add = TRUE)
+
+   source <- file.path(probeDir, "probe.cpp")
+   writeLines(c(
+      "#include <cstddef>",
+      "#if defined(__clang__) && defined(_LIBCPP_VERSION) && \\",
+      "    defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && \\",
+      "    __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 101300",
+      "#pragma message(\"RCPP_PARALLEL_NO_ALIGNED_ALLOCATION\")",
+      "#endif",
+      "int rcppParallelConfigureProbe;"
+   ), source)
+
+   output <- tryCatch(
+      suppressWarnings(system2(
+         rPath,
+         c("CMD", "SHLIB", shQuote(source)),
+         stdout = TRUE,
+         stderr = TRUE
+      )),
+      error = function(cnd) character()
+   )
+
+   any(grepl("RCPP_PARALLEL_NO_ALIGNED_ALLOCATION", output, fixed = TRUE))
+
+}
 
 # check whether user has Makevars file that might cause trouble
 makevars <- Sys.getenv("R_MAKEVARS_USER", unset = "~/.R/Makevars")
@@ -237,7 +276,14 @@ if (!is.na(tbbLib)) {
 # TBB is always enabled: either one was supplied via TBB_LIB / TBB_ROOT, or we
 # built the bundled copy, and failing to do either is fatal above
 define(TBB_ENABLED = TRUE)
-define(PKG_CXXFLAGS = "-DRCPP_PARALLEL_USE_TBB=1")
+tbbCxxFlags <- if (tbbNeedsNoAlignedAllocation()) {
+   "-fno-aligned-allocation"
+} else {
+   ""
+}
+define(TBB_CXXFLAGS = tbbCxxFlags)
+pkgCxxFlags <- c("-DRCPP_PARALLEL_USE_TBB=1", tbbCxxFlags)
+define(PKG_CXXFLAGS = paste(pkgCxxFlags[nzchar(pkgCxxFlags)], collapse = " "))
 
 # macOS needs some extra flags set
 if (Sys.info()[["sysname"]] == "Darwin") {