From faae6f0bbd4d83389b1063786a2b79250cd1d095 Mon Sep 17 00:00:00 2001
From: Viktor Szakats <commit@vsz.me>
Date: Tue, 31 Oct 2023 14:23:17 +0000
Subject: [PATCH] add linux cross llvm clang-rt support 1

---
 _build.sh           | 32 +++++++++++++++++++++++++-------
 _ci-linux-debian.sh | 38 +++++++++++++++++++-------------------
 2 files changed, 44 insertions(+), 26 deletions(-)

diff --git a/_build.sh b/_build.sh
index 723a1da0a..9e0ffbcae 100755
--- a/_build.sh
+++ b/_build.sh
@@ -87,7 +87,6 @@ set -o xtrace -o errexit -o nounset; [ -n "${BASH:-}${ZSH_NAME:-}" ] && set -o p
 #     https://developer.apple.com/forums/thread/715385
 #   - linux: musl alpine why need -static-pie and not -static?
 #   - linux: musl libcurl.so.4.8.0 tweak to be also portable (possible?)
-#   - linux: cross non-musl builds to use libclang_rt (instead of libgcc).
 #   - merge _ci-*.sh scripts into one.
 #   - FIXME: curl-autotools: .map file support and clang builds broken.
 #   - win: Drop x86 builds.
@@ -829,14 +828,18 @@ build_single_target() {
   [ "${_CPU}" = 'x86' ] && _CFLAGS_GLOBAL="${_CFLAGS_GLOBAL} -fno-asynchronous-unwind-tables"
 
   _CCRT='libgcc'  # compiler runtime, 'libgcc' (for libgcc and libstdc++) or 'clang-rt' (for compiler-rt and libc++)
-  # Debian does not support clang-rt for cross-builds easily,
-  # it requires manually installing package `libclang-rt-16-dev` or `libclang-common-15-dev`.
-  if [ "${_CC}" = 'llvm' ] && [ "${_CRT}" = 'musl' ]; then
-    _CCRT='clang-rt'
-  elif [ "${_TOOLCHAIN}" = 'llvm-apple' ] || \
-       [ "${_TOOLCHAIN}" = 'llvm-mingw' ]; then
+  if [ "${_TOOLCHAIN}" = 'llvm-apple' ] || \
+     [ "${_TOOLCHAIN}" = 'llvm-mingw' ]; then
     # Not an option
     _CCRT='clang-rt'
+  elif [ "${_CC}" = 'llvm' ]; then
+    if [ "${_DISTRO}" = 'alpine' ]; then
+      _CCRT='clang-rt'
+    # Debian does not support clang-rt for cross-builds easily,
+    # it requires manually installing package `libclang-rt-16-dev` or `libclang-common-15-dev`.
+    elif [ "${_DISTRO}" = 'debian' ] && [ -d 'my-pkg/usr/lib/clang' ]; then
+      _CCRT='clang-rt'
+    fi
   fi
 
   export _LD
@@ -1230,6 +1233,21 @@ build_single_target() {
         _LDFLAGS_GLOBAL="${_LDFLAGS_GLOBAL} -nostdlib -nodefaultlibs -nostartfiles -L${libprefix} ${libprefix}/crt1.o ${libprefix}/crti.o -L${ccrtdir} ${libprefix}/crtn.o"
         _LIBS_GLOBAL="${_LIBS_GLOBAL} -lc ${ccrtlib}"
       else
+        if [ "${_DISTRO}" = 'debian' ] && [ "${unamem}" != "${_machine}" ] && [ -d 'my-pkg/usr/lib/clang' ]; then
+          # If we have the target CPU's clang-rt package installed, use it:
+          ccrtdir="$(find -L \
+            "$(pwd)/my-pkg/usr/lib/clang" -mindepth 1 -maxdepth 1 -type d | sort | tail -n 1)"  # ./my-pkg/usr/lib/clang/15/lib/linux
+          if [ -z "${ccrtdir}" ]; then
+            >&2 echo '! Error: Failed to detect cross-clang-rt env root.'
+            exit 1
+          fi
+          ccrtdir="${ccrtdir}/lib/linux"
+          ccrtlib="${ccrtdir}/libclang_rt.builtins-${_machine}.a"
+          ccrtlib="$(basename "${ccrtlib}" | cut -c 4-)"  # delete 'lib' prefix
+          ccrtlib="-l${ccrtlib%.*}"  # clang_rt.builtins-aarch64 or gcc
+          _LDFLAGS_GLOBAL="${_LDFLAGS_GLOBAL} -nodefaultlibs -L${ccrtdir}"
+          _LIBS_GLOBAL="${_LIBS_GLOBAL} -lc ${ccrtlib}"
+        fi
         _LDFLAGS_GLOBAL="${_LDFLAGS_GLOBAL} -rtlib=compiler-rt"
         # `-Wc,...` is necessary for libtool to pass this option to the compiler
         # at link-time. Otherwise libtool strips it.
diff --git a/_ci-linux-debian.sh b/_ci-linux-debian.sh
index 33b3242e0..579ae4bfb 100755
--- a/_ci-linux-debian.sh
+++ b/_ci-linux-debian.sh
@@ -29,6 +29,25 @@ elif [[ "${CW_CONFIG:-}" = *'linux'* ]]; then
   if [[ "${CW_CONFIG:-}" = *'gcc'* ]]; then
     extra="${extra} gcc${CW_GCCSUFFIX} g++${CW_GCCSUFFIX}"
     export CW_CCSUFFIX="${CW_GCCSUFFIX}"
+  else
+    # These packages do not install due to dependency requirements.
+    # We download unpack them manually as a workaround.
+    if [ "${CW_CCSUFFIX}" = '-15' ]; then
+      # ./my-pkg/usr/lib/clang/15/lib
+      # ./my-pkg/usr/lib/llvm-15/lib/clang/15.0.6/lib/linux/libclang_rt.builtins-aarch64.a
+      if [ "$(uname -m)" = 'aarch64' ]; then
+        dl="${dl} libclang-common${CW_CCSUFFIX}-dev:amd64"
+      else
+        dl="${dl} libclang-common${CW_CCSUFFIX}-dev:arm64"
+      fi
+    else
+      # ./my-pkg/usr/lib/llvm-16/lib/clang/16/lib/linux/libclang_rt.builtins-aarch64.a
+      if [ "$(uname -m)" = 'aarch64' ]; then
+        dl="${dl} libclang-rt${CW_CCSUFFIX}-dev:amd64"
+      else
+        dl="${dl} libclang-rt${CW_CCSUFFIX}-dev:arm64"
+      fi
+    fi
   fi
   if [[ "${CW_CONFIG:-}" = *'musl'* ]]; then
     extra="${extra} musl musl-dev"
@@ -46,25 +65,6 @@ elif [[ "${CW_CONFIG:-}" = *'linux'* ]]; then
       else
         extra="${extra} g++${CW_GCCSUFFIX}-aarch64-linux-gnu"
       fi
-    else
-      # These packages do not install due to dependency requirements.
-      # We download unpack them manually as a workaround.
-      if [ "${CW_CCSUFFIX}" = '-15' ]; then
-        # ./my-pkg/usr/lib/clang/15/lib
-        # ./my-pkg/usr/lib/llvm-15/lib/clang/15.0.6/lib/linux/libclang_rt.builtins-aarch64.a
-        if [ "$(uname -m)" = 'aarch64' ]; then
-          dl="${dl} libclang-common${CW_CCSUFFIX}-dev:amd64"
-        else
-          dl="${dl} libclang-common${CW_CCSUFFIX}-dev:arm64"
-        fi
-      else
-        # ./my-pkg/usr/lib/llvm-16/lib/clang/16/lib/linux/libclang_rt.builtins-aarch64.a
-        if [ "$(uname -m)" = 'aarch64' ]; then
-          dl="${dl} libclang-rt${CW_CCSUFFIX}-dev:amd64"
-        else
-          dl="${dl} libclang-rt${CW_CCSUFFIX}-dev:arm64"
-        fi
-      fi
     fi
     # for openssl 'secure-memory' feature
     if [ "$(uname -m)" = 'aarch64' ]; then