llvm/cmake/config.guess: add support for riscv32 and riscv64

[gokturk]

Summary

LLVM configuration fails with 'unable to guess system type' on riscv64. Add support for detecting riscv32 and riscv64 systems.

[gokturk]

Ping

[gokturk]

Ping

[luismarques]

Isn't the correct fix for this to update config.guess with the authoritative one from GNU?

curl "http://git.savannah.gnu.org/gitweb/?p=config.git;a=blob_plain;f=config.guess;hb=HEAD" -o llvm/cmake/config.guess

[gokturk]

In D68899#1870096, @luismarques wrote:

Isn't the correct fix for this to update config.guess with the authoritative one from GNU?

curl "http://git.savannah.gnu.org/gitweb/?p=config.git;a=blob_plain;f=config.guess;hb=HEAD" -o llvm/cmake/config.guess

The current config.guess is GPL-2 or later. The upstream config.guess is GPL-3. I was under the impression that LLVM upstream wanted to maintain a GPL-2 license. So I wrote my own version.

[luismarques]

In D68899#1872213, @gokturk wrote:

The current config.guess is GPL-2 or later. The upstream config.guess is GPL-3. I was under the impression that LLVM upstream wanted to maintain a GPL-2 license. So I wrote my own version.

I also thought that might be a problem, but there are two more config.guess files in the monorepo, and one of them is GPL-3 (polly/lib/External/isl/config.guess), but maybe that's not considered core to LLVM enough to matter? I'm not sure to what extent a configure script is considered to affect the general LLVM license...

[gokturk]

In D68899#1872251, @luismarques wrote:

In D68899#1872213, @gokturk wrote:

The current config.guess is GPL-2 or later. The upstream config.guess is GPL-3. I was under the impression that LLVM upstream wanted to maintain a GPL-2 license. So I wrote my own version.

I also thought that might be a problem, but there are two more config.guess files in the monorepo, and one of them is GPL-3 (polly/lib/External/isl/config.guess), but maybe that's not considered core to LLVM enough to matter? I'm not sure to what extent a configure script is considered to affect the general LLVM license...

I couldn't find anything in the comment messages regarding a license issue. I do see that Haiku support was added just like this (https://github.com/llvm/llvm-project/commit/9590c532b892743040b7a3ea8a8308098e1aff1e#diff-becde2e85ab9b9a6321925ea7aec6815), instead of simply having config.guess updated from its upstream. There ought to be a reason why nobody updated it since 2011. Regardless, this patch sidesteps the license question and should be safe to apply.

[luismarques]

LGTM.

[Meinersbur]

In D68899#1872251, @luismarques wrote:

In D68899#1872213, @gokturk wrote:

The current config.guess is GPL-2 or later. The upstream config.guess is GPL-3. I was under the impression that LLVM upstream wanted to maintain a GPL-2 license. So I wrote my own version.

I also thought that might be a problem, but there are two more config.guess files in the monorepo, and one of them is GPL-3 (polly/lib/External/isl/config.guess), but maybe that's not considered core to LLVM enough to matter? I'm not sure to what extent a configure script is considered to affect the general LLVM license...

That files comes from creating a distribution of ISL, using whatever version of autoconf is on the system. It contains the following passage:

# As a special exception to the GNU General Public License, if you
# distribute this file as part of a program that contains a
# configuration script generated by Autoconf, you may include it under
# the same distribution terms that you use for the rest of that
# program.  This Exception is an additional permission under section 7
# of the GNU General Public License, version 3 ("GPLv3").

This file is not used since we re-created the build system using cmake. I could remove it if deemed necessary.

By contrast, I am more surprised that we slapped a Apache-2 license on ConvertUTF.cpp/.h and nobody seem to care: D66390.

[luismarques]

Thanks for the insight @Meinersbur .
(edit: removed comment about reverting this; that was meant for D69869)

llvm/cmake/config.guess

EOF
   echo powerpc64-unknown-linux-gnu
   exit ;;
     ppc64le:Linux:*:*)
   echo powerpc64le-unknown-linux-gnu
   exit ;;
     ppc:Linux:*:*)
   echo powerpc-unknown-linux-gnu
   exit ;;
+    riscv32:Linux:*:* | riscv64:Linux:*:*)
+  LIBC=gnu
+  eval $set_cc_for_build
+  # Do not check for __GLIBC__ because uclibc defines it too
+  sed 's/^ //' << EOF >$dummy.c
+  #include <features.h>
+  #if defined(__UCLIBC__)
+  LIBC=uclibc
+  #elif defined(__dietlibc__)
+  LIBC=dietlibc
+  #endif
+EOF
+  eval `$CC_FOR_BUILD -E $dummy.c 2>/dev/null | grep '^LIBC'`
+
+  # There is no features test macro for musl
+  # Follow the GNU's config.guess approach of
+  # checking the output of ldd
+  if command -v ldd >/dev/null && \
+    ldd --version 2>&1 | grep -q ^musl; then
+      LIBC=musl
+  fi
+
+  echo ${UNAME_MACHINE}-unknown-linux-${LIBC}
+  exit ;;
     s390:Linux:*:* | s390x:Linux:*:*)
   echo ${UNAME_MACHINE}-ibm-linux
   exit ;;
     sh64*:Linux:*:*)
   echo ${UNAME_MACHINE}-unknown-linux-gnu
   exit ;;
     sh*:Linux:*:*)
   echo ${UNAME_MACHINE}-unknown-linux-gnu