Always link to libgcc for musl targets.

Fixes issues with numerous missing symbols from libgcc routines that are
not currently implemented in Rust's compiler builtins. These include:
- __trunctfsf2
- __ctzdi2
- __letf2
- __addtf3

These missing symbols all seem to be soft-float and integer arithmetic routines.

Author: Alexhuszagh

.changes/986.json

@@ -0,0 +1,5 @@
+{
+    "type": "fixed",
+    "description": "always link to libgcc with musl targets to patch missing rust compiler builtins.",
+    "issues": [906, 985]
+}

docker/Dockerfile.aarch64-unknown-linux-musl

@@ -20,11 +20,12 @@ ENV CROSS_MUSL_SYSROOT=/usr/local/aarch64-linux-musl
 COPY musl-symlink.sh /
 RUN /musl-symlink.sh $CROSS_MUSL_SYSROOT aarch64
 
-COPY aarch64-linux-musl-gcc.sh /usr/bin/
+COPY musl-linker.sh /usr/bin/
 
 COPY qemu-runner /
 
-ENV CARGO_TARGET_AARCH64_UNKNOWN_LINUX_MUSL_LINKER=aarch64-linux-musl-gcc.sh \
+ENV CROSS_TARGET_LINKER=aarch64-linux-musl-gcc \
+    CARGO_TARGET_AARCH64_UNKNOWN_LINUX_MUSL_LINKER=musl-linker.sh \
     CARGO_TARGET_AARCH64_UNKNOWN_LINUX_MUSL_RUNNER="/qemu-runner aarch64" \
     CC_aarch64_unknown_linux_musl=aarch64-linux-musl-gcc \
     CXX_aarch64_unknown_linux_musl=aarch64-linux-musl-g++ \

docker/Dockerfile.arm-unknown-linux-musleabi

@@ -24,9 +24,12 @@ ENV CROSS_MUSL_SYSROOT=/usr/local/arm-linux-musleabi
 COPY musl-symlink.sh /
 RUN /musl-symlink.sh $CROSS_MUSL_SYSROOT arm
 
+COPY musl-linker.sh /usr/bin/
+
 COPY qemu-runner /
 
-ENV CARGO_TARGET_ARM_UNKNOWN_LINUX_MUSLEABI_LINKER=arm-linux-musleabi-gcc \
+ENV CROSS_TARGET_LINKER=arm-linux-musleabi-gcc \
+    CARGO_TARGET_ARM_UNKNOWN_LINUX_MUSLEABI_LINKER=musl-linker.sh \
     CARGO_TARGET_ARM_UNKNOWN_LINUX_MUSLEABI_RUNNER="/qemu-runner arm" \
     CC_arm_unknown_linux_musleabi=arm-linux-musleabi-gcc \
     CXX_arm_unknown_linux_musleabi=arm-linux-musleabi-g++ \

docker/Dockerfile.arm-unknown-linux-musleabihf

@@ -25,9 +25,12 @@ ENV CROSS_MUSL_SYSROOT=/usr/local/arm-linux-musleabihf
 COPY musl-symlink.sh /
 RUN /musl-symlink.sh $CROSS_MUSL_SYSROOT armhf
 
+COPY musl-linker.sh /usr/bin/
+
 COPY qemu-runner /
 
-ENV CARGO_TARGET_ARM_UNKNOWN_LINUX_MUSLEABIHF_LINKER=arm-linux-musleabihf-gcc \
+ENV CROSS_TARGET_LINKER=arm-linux-musleabihf-gcc \
+    CARGO_TARGET_ARM_UNKNOWN_LINUX_MUSLEABIHF_LINKER=musl-linker.sh \
     CARGO_TARGET_ARM_UNKNOWN_LINUX_MUSLEABIHF_RUNNER="/qemu-runner arm" \
     CC_arm_unknown_linux_musleabihf=arm-linux-musleabihf-gcc \
     CXX_arm_unknown_linux_musleabihf=arm-linux-musleabihf-g++ \

docker/Dockerfile.armv5te-unknown-linux-musleabi

@@ -24,9 +24,12 @@ ENV CROSS_MUSL_SYSROOT=/usr/local/arm-linux-musleabi
 COPY musl-symlink.sh /
 RUN /musl-symlink.sh $CROSS_MUSL_SYSROOT arm
 
+COPY musl-linker.sh /usr/bin/
+
 COPY qemu-runner /
 
-ENV CARGO_TARGET_ARMV5TE_UNKNOWN_LINUX_MUSLEABI_LINKER=arm-linux-musleabi-gcc \
+ENV CROSS_TARGET_LINKER=arm-linux-musleabi-gcc \
+    CARGO_TARGET_ARMV5TE_UNKNOWN_LINUX_MUSLEABI_LINKER=musl-linker.sh \
     CARGO_TARGET_ARMV5TE_UNKNOWN_LINUX_MUSLEABI_RUNNER="/qemu-runner arm" \
     CC_armv5te_unknown_linux_musleabi=arm-linux-musleabi-gcc \
     CXX_armv5te_unknown_linux_musleabi=arm-linux-musleabi-g++ \

docker/Dockerfile.armv7-unknown-linux-musleabi

@@ -25,9 +25,12 @@ ENV CROSS_MUSL_SYSROOT=/usr/local/arm-linux-musleabi
 COPY musl-symlink.sh /
 RUN /musl-symlink.sh $CROSS_MUSL_SYSROOT arm
 
+COPY musl-linker.sh /usr/bin/
+
 COPY qemu-runner /
 
-ENV CARGO_TARGET_ARMV7_UNKNOWN_LINUX_MUSLEABI_LINKER=arm-linux-musleabi-gcc \
+ENV CROSS_TARGET_LINKER=arm-linux-musleabi-gcc \
+    CARGO_TARGET_ARMV7_UNKNOWN_LINUX_MUSLEABI_LINKER=musl-linker.sh \
     CARGO_TARGET_ARMV7_UNKNOWN_LINUX_MUSLEABI_RUNNER="/qemu-runner armv7" \
     CC_armv7_unknown_linux_musleabi=arm-linux-musleabi-gcc \
     CXX_armv7_unknown_linux_musleabi=arm-linux-musleabi-g++ \

docker/Dockerfile.armv7-unknown-linux-musleabihf

@@ -25,9 +25,12 @@ ENV CROSS_MUSL_SYSROOT=/usr/local/arm-linux-musleabihf
 COPY musl-symlink.sh /
 RUN /musl-symlink.sh $CROSS_MUSL_SYSROOT armhf
 
+COPY musl-linker.sh /usr/bin/
+
 COPY qemu-runner /
 
-ENV CARGO_TARGET_ARMV7_UNKNOWN_LINUX_MUSLEABIHF_LINKER=arm-linux-musleabihf-gcc \
+ENV CROSS_TARGET_LINKER=arm-linux-musleabihf-gcc \
+    CARGO_TARGET_ARMV7_UNKNOWN_LINUX_MUSLEABIHF_LINKER=musl-linker.sh \
     CARGO_TARGET_ARMV7_UNKNOWN_LINUX_MUSLEABIHF_RUNNER="/qemu-runner armv7" \
     CC_armv7_unknown_linux_musleabihf=arm-linux-musleabihf-gcc \
     CXX_armv7_unknown_linux_musleabihf=arm-linux-musleabihf-g++ \

docker/Dockerfile.i586-unknown-linux-musl

@@ -20,9 +20,12 @@ ENV CROSS_MUSL_SYSROOT=/usr/local/i586-linux-musl
 COPY musl-symlink.sh /
 RUN /musl-symlink.sh $CROSS_MUSL_SYSROOT i386
 
+COPY musl-linker.sh /usr/bin/
+
 COPY qemu-runner /
 
-ENV CARGO_TARGET_I586_UNKNOWN_LINUX_MUSL_LINKER=i586-linux-musl-gcc \
+ENV CROSS_TARGET_LINKER=i586-linux-musl-gcc \
+    CARGO_TARGET_I586_UNKNOWN_LINUX_MUSL_LINKER=musl-linker.sh \
     CARGO_TARGET_I586_UNKNOWN_LINUX_MUSL_RUNNER="/qemu-runner i586" \
     CC_i586_unknown_linux_musl=i586-linux-musl-gcc \
     CXX_i586_unknown_linux_musl=i586-linux-musl-g++ \

docker/Dockerfile.i686-unknown-linux-musl

@@ -20,9 +20,12 @@ ENV CROSS_MUSL_SYSROOT=/usr/local/i686-linux-musl
 COPY musl-symlink.sh /
 RUN /musl-symlink.sh $CROSS_MUSL_SYSROOT i386
 
+COPY musl-linker.sh /usr/bin/
+
 COPY qemu-runner /
 
-ENV CARGO_TARGET_I686_UNKNOWN_LINUX_MUSL_LINKER=i686-linux-musl-gcc \
+ENV CROSS_TARGET_LINKER=i686-linux-musl-gcc \
+    CARGO_TARGET_I686_UNKNOWN_LINUX_MUSL_LINKER=musl-linker.sh \
     CARGO_TARGET_I686_UNKNOWN_LINUX_MUSL_RUNNER="/qemu-runner i686" \
     CC_i686_unknown_linux_musl=i686-linux-musl-gcc \
     CXX_i686_unknown_linux_musl=i686-linux-musl-g++ \

docker/Dockerfile.mips-unknown-linux-musl

@@ -22,9 +22,12 @@ ENV CROSS_MUSL_SYSROOT=/usr/local/mips-linux-muslsf
 COPY musl-symlink.sh /
 RUN /musl-symlink.sh $CROSS_MUSL_SYSROOT mips-sf
 
+COPY musl-linker.sh /usr/bin/
+
 COPY qemu-runner /
 
-ENV CARGO_TARGET_MIPS_UNKNOWN_LINUX_MUSL_LINKER=mips-linux-muslsf-gcc \
+ENV CROSS_TARGET_LINKER=mips-linux-muslsf-gcc \
+    CARGO_TARGET_MIPS_UNKNOWN_LINUX_MUSL_LINKER=musl-linker.sh \
     CARGO_TARGET_MIPS_UNKNOWN_LINUX_MUSL_RUNNER="/qemu-runner mips" \
     CC_mips_unknown_linux_musl=mips-linux-muslsf-gcc \
     CXX_mips_unknown_linux_musl=mips-linux-muslsf-g++ \

docker/Dockerfile.mips64-unknown-linux-muslabi64

@@ -25,11 +25,12 @@ RUN mkdir -p $CROSS_MUSL_SYSROOT/usr/lib64
 RUN ln -s $CROSS_MUSL_SYSROOT/usr/lib/libc.so $CROSS_MUSL_SYSROOT/usr/lib64/libc.so
 RUN ln -s $CROSS_MUSL_SYSROOT/usr/lib/libc.so.1 $CROSS_MUSL_SYSROOT/usr/lib64/libc.so.1
 
-COPY mips64-linux-muslabi64-gcc.sh /usr/bin/
+COPY musl-linker.sh /usr/bin/
 
 COPY qemu-runner /
 
-ENV CARGO_TARGET_MIPS64_UNKNOWN_LINUX_MUSLABI64_LINKER=mips64-linux-muslabi64-gcc.sh \
+ENV CROSS_TARGET_LINKER=mips64-linux-muslabi64-gcc \
+    CARGO_TARGET_MIPS64_UNKNOWN_LINUX_MUSLABI64_LINKER=musl-linker.sh \
     CARGO_TARGET_MIPS64_UNKNOWN_LINUX_MUSLABI64_RUNNER="/qemu-runner mips64" \
     CC_mips64_unknown_linux_muslabi64=mips64-linux-musl-gcc \
     CXX_mips64_unknown_linux_muslabi64=mips64-linux-musl-g++ \

docker/Dockerfile.mips64el-unknown-linux-muslabi64

@@ -23,7 +23,8 @@ RUN /musl-symlink.sh $CROSS_MUSL_SYSROOT mips64el-sf
 
 COPY qemu-runner /
 
-ENV CARGO_TARGET_MIPS64EL_UNKNOWN_LINUX_MUSLABI64_LINKER=mips64el-linux-muslsf-gcc \
+ENV CROSS_TARGET_LINKER=mips64el-linux-muslsf-gcc \
+    CARGO_TARGET_MIPS64EL_UNKNOWN_LINUX_MUSLABI64_LINKER=musl-linker.sh \
     CARGO_TARGET_MIPS64EL_UNKNOWN_LINUX_MUSLABI64_RUNNER="/qemu-runner mips64el" \
     CC_mips64el_unknown_linux_muslabi64=mips64el-linux-muslsf-gcc \
     CXX_mips64el_unknown_linux_muslabi64=mips64el-linux-muslsf-g++ \

docker/Dockerfile.mipsel-unknown-linux-musl

@@ -22,9 +22,12 @@ ENV CROSS_MUSL_SYSROOT=/usr/local/mipsel-linux-muslsf
 COPY musl-symlink.sh /
 RUN /musl-symlink.sh $CROSS_MUSL_SYSROOT mipsel-sf
 
+COPY musl-linker.sh /usr/bin/
+
 COPY qemu-runner /
 
-ENV CARGO_TARGET_MIPSEL_UNKNOWN_LINUX_MUSL_LINKER=mipsel-linux-muslsf-gcc \
+ENV CROSS_TARGET_LINKER=mipsel-linux-muslsf-gcc \
+    CARGO_TARGET_MIPSEL_UNKNOWN_LINUX_MUSL_LINKER=musl-linker.sh \
     CARGO_TARGET_MIPSEL_UNKNOWN_LINUX_MUSL_RUNNER="/qemu-runner mipsel" \
     CC_mipsel_unknown_linux_musl=mipsel-linux-muslsf-gcc \
     CXX_mipsel_unknown_linux_musl=mipsel-linux-muslsf-g++ \

docker/Dockerfile.x86_64-unknown-linux-musl

@@ -20,9 +20,12 @@ ENV CROSS_MUSL_SYSROOT=/usr/local/x86_64-linux-musl
 COPY musl-symlink.sh /
 RUN /musl-symlink.sh $CROSS_MUSL_SYSROOT x86_64
 
+COPY musl-linker.sh /usr/bin/
+
 COPY qemu-runner /
 
-ENV CARGO_TARGET_X86_64_UNKNOWN_LINUX_MUSL_LINKER=x86_64-linux-musl-gcc \
+ENV CROSS_TARGET_LINKER=x86_64-linux-musl-gcc \
+    CARGO_TARGET_X86_64_UNKNOWN_LINUX_MUSL_LINKER=musl-linker.sh \
     CARGO_TARGET_X86_64_UNKNOWN_LINUX_MUSL_RUNNER="/qemu-runner x86_64" \
     CC_x86_64_unknown_linux_musl=x86_64-linux-musl-gcc \
     CXX_x86_64_unknown_linux_musl=x86_64-linux-musl-g++ \

docker/aarch64-linux-musl-gcc.sh

@@ -0,0 +1,29 @@
+#!/bin/bash
+
+# this fixes a series of issues affecting musl targets, with missing
+# instrinsics that are symbols present in libgcc but not in the compiler
+# builtins. this is therefore a temporary workaround until these
+# issues are fixed. example issues previously discovered are noted below:
+
+# mips64-unknown-linux-musl
+# this linker wrapper works around issue https://github.com/rust-lang/rust/issues/46651
+# which affects toolchains older than 1.48
+# older toolchains require the `-lgcc` linker flag otherwise they fail to link
+
+# mips64-unknown-linux-gnuabi64
+# this fixes an issue of missing symbols from the command lines
+# these soft-float routines are required even for hard-float targets.
+#   (strtod.lo): undefined reference to symbol '__trunctfsf2@@GCC_3.0'
+
+set -x
+set -euo pipefail
+
+main() {
+    if [[ $# -gt 0 ]]; then
+        exec "${CROSS_TARGET_LINKER}" "${@}" -lgcc -static-libgcc
+    else
+        exec "${CROSS_TARGET_LINKER}" "${@}"
+    fi
+}
+
+main "${@}"