build: support RISCV64 build (fixes gh #266)

.docker/Dockerfile.alpine

@@ -51,7 +51,13 @@ RUN apk add --no-cache \
 
 # Install UPX
 ARG ARCH
-RUN wget -O - https://github.com/upx/upx/releases/download/v5.0.0/upx-5.0.0-$(bash -c "echo \${0//v8/}" $ARCH)_linux.tar.xz | tar -xJf - -C /usr/local/bin --strip-components=1 --wildcards "*/upx"
+# UPX isn't supported on RISC-V yet, so skip this
+RUN if [ "$ARCH" != "riscv64" ]; then \
+        wget -O - https://github.com/upx/upx/releases/download/v5.0.0/upx-5.0.0-$(bash -c "echo \${0//v8/}" $ARCH)_linux.tar.xz | tar -xJf - -C /usr/local/bin --strip-components=1 --wildcards "*/upx"; \
+    else \
+        echo "Skipping UPX installation for RISC-V architecture while it is not supported."; \
+        echo "See https://github.com/upx/upx/discussions/793 for details."; \
+    fi
 
 # Install mistletoe
 RUN pip3 install --break-system-packages --root-user-action ignore mistletoe
@@ -67,7 +73,11 @@ RUN bash /usr/local/bin/install-mold.sh
 
 # Install bloaty
 COPY install-bloaty.sh /usr/local/bin/install-bloaty.sh
-RUN bash /usr/local/bin/install-bloaty.sh
+RUN if [ "$ARCH" != "riscv64" ]; then \
+        bash /usr/local/bin/install-bloaty.sh; \
+    else \
+        echo "Skipping bloaty installation for RISC-V."; \
+    fi
 
 # Install all static libraries
 COPY install-static-libs.sh /usr/local/bin/install-static-libs.sh

.docker/Makefile

@@ -1,5 +1,6 @@
 IMAGE_UBUNTU="dwarfs-buildenv"
 IMAGE_ALPINE="dwarfs-buildenv-alpine"
+IMAGE_ALPINE_RISCV="dwarfs-buildenv-alpine-riscv64"
 IMAGE_UBUNTU2204="dwarfs-buildenv-ubuntu2204"
 IMAGE_FEDORA="dwarfs-buildenv-fedora"
 IMAGE_ARCH="dwarfs-buildenv-arch"
@@ -31,6 +32,12 @@ build_alpine:
 run_alpine:
 	@docker run $(COMMON_RUN_OPTS) $(IMAGE_ALPINE)
 
+build_alpine_riscv:
+	docker build -f Dockerfile.alpine -t $(IMAGE_ALPINE_RISCV) --build-arg ARCH=riscv64 .
+
+run_alpine_riscv:
+	@docker run $(COMMON_RUN_OPTS) $(IMAGE_ALPINE_RISCV)
+
 build_ubuntu2204:
 	docker build -f Dockerfile.ubuntu-2204 -t $(IMAGE_UBUNTU2204) .
 

.docker/install-static-libs.sh

@@ -41,12 +41,22 @@ echo "Using $GCC and $CLANG"
 if [[ "$PKGS" == ":ubuntu" ]]; then
     PKGS="file,bzip2,libarchive,flac,libunwind,benchmark,openssl,cpptrace"
     COMPILERS="clang gcc"
-elif [[ "$PKGS" == ":alpine" ]]; then
+elif [[ "$PKGS" == ":alpine"* ]]; then
-    PKGS="benchmark,boost,brotli,cpptrace,double-conversion,flac,fmt,fuse,glog,jemalloc,libarchive,libunwind,libressl,lz4,mimalloc,openssl,xxhash,xz,zstd"
+    if [[ "$PKGS" == ":alpine" ]]; then
+        PKGS="benchmark,boost,brotli,cpptrace,double-conversion,flac,fmt,fuse,glog,jemalloc,libarchive,libunwind,libressl,lz4,mimalloc,openssl,xxhash,xz,zstd"
+    else
+        PKGS="${PKGS#:alpine:}"
+    fi
     export COMMON_CFLAGS="-ffunction-sections -fdata-sections -fmerge-all-constants"
     export COMMON_CXXFLAGS="$COMMON_CFLAGS"
+    export COMMON_LDFLAGS="-fuse-ld=mold"
     # COMPILERS="clang clang-lto clang-minsize-lto gcc"
-    COMPILERS="clang clang-minsize-lto gcc"
+    if [[ "$ARCH" != "x86_64" && "$ARCH" != "aarch64" ]]; then
+        # Let's keep it simple for more exotic architectures
+        COMPILERS="clang-minsize-lto"
+    else
+        COMPILERS="clang clang-minsize-lto gcc"
+    fi
 elif [[ "$PKGS" == ":none" ]]; then
     echo "No libraries to build"
     exit 0
@@ -451,7 +461,9 @@ for COMPILER in $COMPILERS; do
             ./configure --prefix="$prefix" \
                         --without-iconv --without-xml2 --without-expat \
                         --without-bz2lib --without-zlib \
-                        --disable-shared --disable-acl --disable-xattr
+                        --disable-shared --disable-acl --disable-xattr \
+                        --disable-bsdtar --disable-bsdcat --disable-bsdcpio \
+                        --disable-bsdunzip
             make -j$(nproc)
             make install
         done
@@ -472,7 +484,8 @@ for COMPILER in $COMPILERS; do
         cd "$HOME/pkgs/$COMPILER"
         tar xf ../${FLAC_TARBALL}
         cd flac-${FLAC_VERSION}
-        ./configure --prefix="$INSTALL_DIR" --enable-static=yes --enable-shared=no --disable-doxygen-docs --disable-ogg --disable-programs --disable-examples
+        ./configure --prefix="$INSTALL_DIR" --enable-static=yes --enable-shared=no \
+                    --disable-doxygen-docs --disable-ogg --disable-programs --disable-examples
         make -j$(nproc)
         make install
     fi

.github/workflows/build.yml

@@ -200,6 +200,9 @@ jobs:
           - arch: arm64v8
             dist: alpine
             build_type: clang-relsize-libressl-lto-ninja-static
+          - arch: riscv64
+            dist: alpine
+            build_type: clang-relsize-libressl-lto-ninja-static
           - arch: amd64
             dist: alpine
             build_type: clang-relsize-minimal-lto-ninja-static

.github/workflows/docker-run-build.yml

@@ -36,6 +36,9 @@ jobs:
       - Linux
       - ${{ inputs.build_arch }}
 
+    # Building a docker container on RISC-V can take an awful long time
+    timeout-minutes: 2880
+
     steps:
       - name: Checkout
         uses: actions/checkout@v4

CMakeLists.txt

@@ -1053,6 +1053,13 @@ if(STATIC_BUILD_DO_NOT_USE OR WIN32)
           COMMAND ${UPX_EXE} -9 --best -o ${UNIVERSAL_OUT} $<TARGET_FILE:${tgt}>
           WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}
         )
+      else()
+        add_custom_command(
+          OUTPUT ${UNIVERSAL_OUT}
+          COMMAND ${CMAKE_COMMAND} -E copy $<TARGET_FILE:${tgt}> ${UNIVERSAL_OUT}
+          WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}
+          COMMENT "UPX not found, copying binary without compression"
+        )
       endif()
     endif()
 

cmake/folly.cmake

@@ -150,6 +150,11 @@ target_include_directories(
   $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/folly>
 )
 
+# On platforms other than x86 / arm, we need to use the fallback
+if(NOT CMAKE_SYSTEM_PROCESSOR MATCHES "x86_64|aarch64")
+  target_compile_definitions(dwarfs_folly_lite PUBLIC FOLLY_F14_FORCE_FALLBACK=1)
+endif()
+
 if(NOT PREFER_SYSTEM_FAST_FLOAT)
   target_include_directories(
     dwarfs_folly_lite SYSTEM PRIVATE