Add support to build LLVM/clang with C and C++ support

We currently have a stale "llvm" branch, that does not build.
However, there is clear demand in the RISC-V toolchain community
for a working LLVM on top of a recent GNU toolchain.
In order to build such a toolchain, quite some LLVM and clang know-how is
required to avoid path issues at LLVM build time or later when using clang.
The main purpose of this commit is to demonstrate a way to combine
the RISC-V GNU toolchain repo with LLVM, with the intent to save
others hours of frustration, debugging time or support time.

Signed-off-by: Christoph Müllner <christoph.muellner@vrull.eu>

1 files changed, 40 insertions, 13 deletions

diff --git a/configure b/configure
index 6b73555..5afcc61 100755
--- a/configure
+++ b/configure
@@ -587,6 +587,7 @@ LIBOBJS
 qemu_targets
 enable_libsanitizer
 with_linux_headers_src
+with_llvm_src
 with_pk_src
 with_spike_src
 with_qemu_src
@@ -596,6 +597,7 @@ with_glibc_src
 with_newlib_src
 with_binutils_src
 with_gcc_src
+enable_llvm
 enable_gdb
 with_guile
 with_system_zlib
@@ -651,7 +653,6 @@ infodir
 docdir
 oldincludedir
 includedir
-runstatedir
 localstatedir
 sharedstatedir
 sysconfdir
@@ -690,6 +691,7 @@ with_host
 with_system_zlib
 with_guile
 enable_gdb
+enable_llvm
 with_gcc_src
 with_binutils_src
 with_newlib_src
@@ -699,6 +701,7 @@ with_gdb_src
 with_qemu_src
 with_spike_src
 with_pk_src
+with_llvm_src
 with_linux_headers_src
 enable_libsanitizer
 enable_qemu_system
@@ -749,7 +752,6 @@ datadir='${datarootdir}'
 sysconfdir='${prefix}/etc'
 sharedstatedir='${prefix}/com'
 localstatedir='${prefix}/var'
-runstatedir='${localstatedir}/run'
 includedir='${prefix}/include'
 oldincludedir='/usr/include'
 docdir='${datarootdir}/doc/${PACKAGE_TARNAME}'
@@ -1002,15 +1004,6 @@ do
   | -silent | --silent | --silen | --sile | --sil)
     silent=yes ;;
 
-  -runstatedir | --runstatedir | --runstatedi | --runstated \
-  | --runstate | --runstat | --runsta | --runst | --runs \
-  | --run | --ru | --r)
-    ac_prev=runstatedir ;;
-  -runstatedir=* | --runstatedir=* | --runstatedi=* | --runstated=* \
-  | --runstate=* | --runstat=* | --runsta=* | --runst=* | --runs=* \
-  | --run=* | --ru=* | --r=*)
-    runstatedir=$ac_optarg ;;
-
   -sbindir | --sbindir | --sbindi | --sbind | --sbin | --sbi | --sb)
     ac_prev=sbindir ;;
   -sbindir=* | --sbindir=* | --sbindi=* | --sbind=* | --sbin=* \
@@ -1148,7 +1141,7 @@ fi
 for ac_var in	exec_prefix prefix bindir sbindir libexecdir datarootdir \
 		datadir sysconfdir sharedstatedir localstatedir includedir \
 		oldincludedir docdir infodir htmldir dvidir pdfdir psdir \
-		libdir localedir mandir runstatedir
+		libdir localedir mandir
 do
   eval ac_val=\$$ac_var
   # Remove trailing slashes.
@@ -1301,7 +1294,6 @@ Fine tuning of the installation directories:
   --sysconfdir=DIR        read-only single-machine data [PREFIX/etc]
   --sharedstatedir=DIR    modifiable architecture-independent data [PREFIX/com]
   --localstatedir=DIR     modifiable single-machine data [PREFIX/var]
-  --runstatedir=DIR       modifiable per-process data [LOCALSTATEDIR/run]
   --libdir=DIR            object code libraries [EPREFIX/lib]
   --includedir=DIR        C header files [PREFIX/include]
   --oldincludedir=DIR     C header files for non-gcc [/usr/include]
@@ -1339,6 +1331,7 @@ Optional Features:
                           slow, only enable it when developing gcc
                           [--disable-gcc-checking]
   --disable-gdb           Don't build GDB, as it's not upstream
+  --enable-llvm           Build LLVM (clang)
   --enable-libsanitizer   Build libsanitizer, which only supports rv64
   --enable-qemu-system    Build qemu with system-mode emulation
 
@@ -1375,6 +1368,7 @@ Optional Packages:
   --with-qemu-src         Set qemu source path, use builtin source by default
   --with-spike-src        Set spike source path, use builtin source by default
   --with-pk-src           Set pk source path, use builtin source by default
+  --with-llvm-src         Set llvm source path, use builtin source by default
   --with-linux-headers-src
                           Set linux-headers source path, use builtin source by
                           default
@@ -3556,6 +3550,20 @@ else
 
 fi
 
+# Check whether --enable-llvm was given.
+if test "${enable_llvm+set}" = set; then :
+  enableval=$enable_llvm; enable_llvm=yes
+fi
+
+
+if test "x$enable_llvm" != xyes; then :
+  enable_llvm=--disable-llvm
+
+else
+  enable_llvm=--enable-llvm
+
+fi
+
 
 
 {
@@ -3729,6 +3737,25 @@ else
 fi
 
 	}
+{
+
+# Check whether --with-llvm-src was given.
+if test "${with_llvm_src+set}" = set; then :
+  withval=$with_llvm_src;
+else
+  with_llvm_src=default
+
+fi
+
+	  if test "x$with_llvm_src" != xdefault; then :
+  with_llvm_src=$with_llvm_src
+
+else
+  with_llvm_src="\$(srcdir)/llvm"
+
+fi
+
+	}
 
 
 # Check whether --with-linux-headers-src was given.