Merge #1125

bors[bot] · Alexhuszagh · web-flow · commit a0721d8a4809 · 2022-11-12T12:17:30.000Z
1125: Always link to libc when compiling musl targets. r=Emilgardis a=Alexhuszagh This fixes a regression when changing musl targets to always statically link to libstdc++, and the static version of libstdc++ can reference but be missing requiring symbols from libc. Due to the linking order of Rust, these symbols sometimes are not resolved. This ensures that all binaries with external C++ dependencies cross-compiled for musl targets, such as `re2`, will be properly linked. Closes #1124. Co-authored-by: Alex Huszagh <ahuszagh@gmail.com>
diff --git a/.changes/1063-1125.json b/.changes/1063-1125.json
@@ -9,5 +9,10 @@
         "description": "fixed C++ support for musl targets.",
         "issues": [902],
         "breaking": true
+    },
+    {
+        "type": "fixed",
+        "description": "always link to libc when compiling alpine since static libstdc++ may have undefined references to libc symbols.",
+        "issues": [1124]
     }
 ]
diff --git a/docker/Dockerfile.arm-unknown-linux-musleabi b/docker/Dockerfile.arm-unknown-linux-musleabi
@@ -27,7 +27,9 @@ RUN /musl-symlink.sh $CROSS_SYSROOT arm
 
 COPY qemu-runner base-runner.sh /
 
-ENV CARGO_TARGET_ARM_UNKNOWN_LINUX_MUSLEABI_LINKER="$CROSS_TOOLCHAIN_PREFIX"gcc \
+COPY musl-gcc.sh /usr/bin/"$CROSS_TOOLCHAIN_PREFIX"gcc.sh
+
+ENV CARGO_TARGET_ARM_UNKNOWN_LINUX_MUSLEABI_LINKER="$CROSS_TOOLCHAIN_PREFIX"gcc.sh \
     CARGO_TARGET_ARM_UNKNOWN_LINUX_MUSLEABI_RUNNER="/qemu-runner arm" \
     CC_arm_unknown_linux_musleabi="$CROSS_TOOLCHAIN_PREFIX"gcc \
     CXX_arm_unknown_linux_musleabi="$CROSS_TOOLCHAIN_PREFIX"g++ \
diff --git a/docker/Dockerfile.arm-unknown-linux-musleabihf b/docker/Dockerfile.arm-unknown-linux-musleabihf
@@ -28,7 +28,9 @@ RUN /musl-symlink.sh $CROSS_SYSROOT armhf
 
 COPY qemu-runner base-runner.sh /
 
-ENV CARGO_TARGET_ARM_UNKNOWN_LINUX_MUSLEABIHF_LINKER="$CROSS_TOOLCHAIN_PREFIX"gcc \
+COPY musl-gcc.sh /usr/bin/"$CROSS_TOOLCHAIN_PREFIX"gcc.sh
+
+ENV CARGO_TARGET_ARM_UNKNOWN_LINUX_MUSLEABIHF_LINKER="$CROSS_TOOLCHAIN_PREFIX"gcc.sh \
     CARGO_TARGET_ARM_UNKNOWN_LINUX_MUSLEABIHF_RUNNER="/qemu-runner armhf" \
     CC_arm_unknown_linux_musleabihf="$CROSS_TOOLCHAIN_PREFIX"gcc \
     CXX_arm_unknown_linux_musleabihf="$CROSS_TOOLCHAIN_PREFIX"g++ \
diff --git a/docker/Dockerfile.armv7-unknown-linux-musleabi b/docker/Dockerfile.armv7-unknown-linux-musleabi
@@ -28,7 +28,9 @@ RUN /musl-symlink.sh $CROSS_SYSROOT arm
 
 COPY qemu-runner base-runner.sh /
 
-ENV CARGO_TARGET_ARMV7_UNKNOWN_LINUX_MUSLEABI_LINKER="$CROSS_TOOLCHAIN_PREFIX"gcc \
+COPY musl-gcc.sh /usr/bin/"$CROSS_TOOLCHAIN_PREFIX"gcc.sh
+
+ENV CARGO_TARGET_ARMV7_UNKNOWN_LINUX_MUSLEABI_LINKER="$CROSS_TOOLCHAIN_PREFIX"gcc.sh \
     CARGO_TARGET_ARMV7_UNKNOWN_LINUX_MUSLEABI_RUNNER="/qemu-runner armv7" \
     CC_armv7_unknown_linux_musleabi="$CROSS_TOOLCHAIN_PREFIX"gcc \
     CXX_armv7_unknown_linux_musleabi="$CROSS_TOOLCHAIN_PREFIX"g++ \
diff --git a/docker/Dockerfile.armv7-unknown-linux-musleabihf b/docker/Dockerfile.armv7-unknown-linux-musleabihf
@@ -28,7 +28,9 @@ RUN /musl-symlink.sh $CROSS_SYSROOT armhf
 
 COPY qemu-runner base-runner.sh /
 
-ENV CARGO_TARGET_ARMV7_UNKNOWN_LINUX_MUSLEABIHF_LINKER="$CROSS_TOOLCHAIN_PREFIX"gcc \
+COPY musl-gcc.sh /usr/bin/"$CROSS_TOOLCHAIN_PREFIX"gcc.sh
+
+ENV CARGO_TARGET_ARMV7_UNKNOWN_LINUX_MUSLEABIHF_LINKER="$CROSS_TOOLCHAIN_PREFIX"gcc.sh \
     CARGO_TARGET_ARMV7_UNKNOWN_LINUX_MUSLEABIHF_RUNNER="/qemu-runner armv7hf" \
     CC_armv7_unknown_linux_musleabihf="$CROSS_TOOLCHAIN_PREFIX"gcc \
     CXX_armv7_unknown_linux_musleabihf="$CROSS_TOOLCHAIN_PREFIX"g++ \
diff --git a/docker/Dockerfile.i586-unknown-linux-musl b/docker/Dockerfile.i586-unknown-linux-musl
@@ -23,7 +23,9 @@ RUN /musl-symlink.sh $CROSS_SYSROOT i386
 
 COPY qemu-runner base-runner.sh /
 
-ENV CARGO_TARGET_I586_UNKNOWN_LINUX_MUSL_LINKER="$CROSS_TOOLCHAIN_PREFIX"gcc \
+COPY musl-gcc.sh /usr/bin/"$CROSS_TOOLCHAIN_PREFIX"gcc.sh
+
+ENV CARGO_TARGET_I586_UNKNOWN_LINUX_MUSL_LINKER="$CROSS_TOOLCHAIN_PREFIX"gcc.sh \
     CARGO_TARGET_I586_UNKNOWN_LINUX_MUSL_RUNNER="/qemu-runner i586" \
     CC_i586_unknown_linux_musl="$CROSS_TOOLCHAIN_PREFIX"gcc \
     CXX_i586_unknown_linux_musl="$CROSS_TOOLCHAIN_PREFIX"g++ \
diff --git a/docker/Dockerfile.i686-unknown-linux-musl b/docker/Dockerfile.i686-unknown-linux-musl
@@ -23,7 +23,9 @@ RUN /musl-symlink.sh $CROSS_SYSROOT i386
 
 COPY qemu-runner base-runner.sh /
 
-ENV CARGO_TARGET_I686_UNKNOWN_LINUX_MUSL_LINKER="$CROSS_TOOLCHAIN_PREFIX"gcc \
+COPY musl-gcc.sh /usr/bin/"$CROSS_TOOLCHAIN_PREFIX"gcc.sh
+
+ENV CARGO_TARGET_I686_UNKNOWN_LINUX_MUSL_LINKER="$CROSS_TOOLCHAIN_PREFIX"gcc.sh \
     CARGO_TARGET_I686_UNKNOWN_LINUX_MUSL_RUNNER="/qemu-runner i686" \
     CC_i686_unknown_linux_musl="$CROSS_TOOLCHAIN_PREFIX"gcc \
     CXX_i686_unknown_linux_musl="$CROSS_TOOLCHAIN_PREFIX"g++ \
diff --git a/docker/Dockerfile.mips-unknown-linux-musl b/docker/Dockerfile.mips-unknown-linux-musl
@@ -27,7 +27,9 @@ RUN /musl-symlink.sh $CROSS_SYSROOT mips-sf
 
 COPY qemu-runner base-runner.sh /
 
-ENV CARGO_TARGET_MIPS_UNKNOWN_LINUX_MUSL_LINKER="$CROSS_TOOLCHAIN_PREFIX"gcc \
+COPY musl-gcc.sh /usr/bin/"$CROSS_TOOLCHAIN_PREFIX"gcc.sh
+
+ENV CARGO_TARGET_MIPS_UNKNOWN_LINUX_MUSL_LINKER="$CROSS_TOOLCHAIN_PREFIX"gcc.sh \
     CARGO_TARGET_MIPS_UNKNOWN_LINUX_MUSL_RUNNER="/qemu-runner mips" \
     CC_mips_unknown_linux_musl="$CROSS_TOOLCHAIN_PREFIX"gcc \
     CXX_mips_unknown_linux_musl="$CROSS_TOOLCHAIN_PREFIX"g++ \
diff --git a/docker/Dockerfile.mipsel-unknown-linux-musl b/docker/Dockerfile.mipsel-unknown-linux-musl
@@ -27,7 +27,9 @@ RUN /musl-symlink.sh $CROSS_SYSROOT mipsel-sf
 
 COPY qemu-runner base-runner.sh /
 
-ENV CARGO_TARGET_MIPSEL_UNKNOWN_LINUX_MUSL_LINKER="$CROSS_TOOLCHAIN_PREFIX"gcc \
+COPY musl-gcc.sh /usr/bin/"$CROSS_TOOLCHAIN_PREFIX"gcc.sh
+
+ENV CARGO_TARGET_MIPSEL_UNKNOWN_LINUX_MUSL_LINKER="$CROSS_TOOLCHAIN_PREFIX"gcc.sh \
     CARGO_TARGET_MIPSEL_UNKNOWN_LINUX_MUSL_RUNNER="/qemu-runner mipsel" \
     CC_mipsel_unknown_linux_musl="$CROSS_TOOLCHAIN_PREFIX"gcc \
     CXX_mipsel_unknown_linux_musl="$CROSS_TOOLCHAIN_PREFIX"g++ \
diff --git a/docker/Dockerfile.x86_64-unknown-linux-musl b/docker/Dockerfile.x86_64-unknown-linux-musl
@@ -23,7 +23,9 @@ RUN /musl-symlink.sh $CROSS_SYSROOT x86_64
 
 COPY qemu-runner base-runner.sh /
 
-ENV CARGO_TARGET_X86_64_UNKNOWN_LINUX_MUSL_LINKER="$CROSS_TOOLCHAIN_PREFIX"gcc \
+COPY musl-gcc.sh /usr/bin/"$CROSS_TOOLCHAIN_PREFIX"gcc.sh
+
+ENV CARGO_TARGET_X86_64_UNKNOWN_LINUX_MUSL_LINKER="$CROSS_TOOLCHAIN_PREFIX"gcc.sh \
     CARGO_TARGET_X86_64_UNKNOWN_LINUX_MUSL_RUNNER="/qemu-runner x86_64" \
     CC_x86_64_unknown_linux_musl="$CROSS_TOOLCHAIN_PREFIX"gcc \
     CXX_x86_64_unknown_linux_musl="$CROSS_TOOLCHAIN_PREFIX"g++ \
diff --git a/docker/aarch64-linux-musl-gcc.sh b/docker/aarch64-linux-musl-gcc.sh
@@ -12,15 +12,26 @@ set -euo pipefail
 
 main() {
     local minor
+    local flags=()
+    local target="aarch64-unknown-linux-musl"
     minor=$(rustc_minor_version)
 
-    if (( minor >= 48 )) || [[ $# -eq 0 ]]; then
+    if [[ $# -eq 0 ]]; then
         # no workaround
-        exec "${CROSS_TOOLCHAIN_PREFIX}gcc" "${@}"
+        true
+    elif (( minor >= 48 )) && [[ -n "${CROSS_RUST_SYSROOT:-}" ]]; then
+        # find compiler builtins from the sysroot. this also ensures
+        # if for whatever reason the linker is invoked outside of
+        # cross's build system, we link to libgcc instead.
+        local dir="${CROSS_RUST_SYSROOT}/lib/rustlib/${target}/lib"
+        local builtins
+        builtins=$(ls -1 "${dir}"/libcompiler_builtins*.rlib)
+        flags+=("${builtins}" -lc)
     else
-        # apply workaround
-        exec "${CROSS_TOOLCHAIN_PREFIX}gcc" "${@}" -lgcc -static-libgcc
+        flags+=(-lgcc -static-libgcc -lc)
     fi
+
+    exec "${CROSS_TOOLCHAIN_PREFIX}gcc" "${@}" "${flags[@]}"
 }
 
 main "${@}"
diff --git a/docker/musl-gcc.sh b/docker/musl-gcc.sh
@@ -0,0 +1,20 @@
+#!/bin/bash
+
+# this works around missing libc routines when compiling
+# against a static libstdc++, which we always do on musl after
+# https://github.com/cross-rs/cross/issues/902. the reason
+# otherwise, we are missing crucial routines as as `setlocale`,
+# `__cxa_atexit`, and others.
+
+set -x
+set -euo pipefail
+
+main() {
+    if [[ $# -eq 0 ]]; then
+        exec "${CROSS_TOOLCHAIN_PREFIX}"gcc "${@}"
+    else
+        exec "${CROSS_TOOLCHAIN_PREFIX}"gcc "${@}" -lc
+    fi
+}
+
+main "${@}"
diff --git a/docker/rust-1-65-musl-gcc.sh b/docker/rust-1-65-musl-gcc.sh
@@ -23,10 +23,12 @@ main() {
     local minor
     minor=$(rustc_minor_version)
 
-    if (( minor >= 65 )) || [[ $# -eq 0 ]]; then
+    if [[ $# -eq 0 ]]; then
         exec "${CROSS_TOOLCHAIN_PREFIX}gcc" "${@}"
+    elif (( minor >= 65 )); then
+        exec "${CROSS_TOOLCHAIN_PREFIX}gcc" "${@}" -lc
     else
-        exec "${CROSS_TOOLCHAIN_PREFIX}gcc" "${@}" -lgcc -static-libgcc
+        exec "${CROSS_TOOLCHAIN_PREFIX}gcc" "${@}" -lgcc -static-libgcc -lc
     fi
 }
 
diff --git a/src/docker/shared.rs b/src/docker/shared.rs
@@ -1030,6 +1030,10 @@ impl DockerCommandExt for Command {
         self.args(["-e", "PKG_CONFIG_ALLOW_CROSS=1"])
             .args(["-e", &format!("XARGO_HOME={}", dirs.xargo_mount_path())])
             .args(["-e", &format!("CARGO_HOME={}", dirs.cargo_mount_path())])
+            .args([
+                "-e",
+                &format!("CROSS_RUST_SYSROOT={}", dirs.sysroot_mount_path()),
+            ])
             .args(["-e", "CARGO_TARGET_DIR=/target"])
             .args(["-e", &cross_runner]);
         if options.cargo_variant.uses_zig() {

Original file line number	Diff line number	Diff line change
`@@ -9,5 +9,10 @@`
`9`	`9`	`"description": "fixed C++ support for musl targets.",`
`10`	`10`	`"issues": [902],`
`11`	`11`	`"breaking": true`
	`12`	`+ },`
	`13`	`+ {`
	`14`	`+ "type": "fixed",`
	`15`	`+ "description": "always link to libc when compiling alpine since static libstdc++ may have undefined references to libc symbols.",`
	`16`	`+ "issues": [1124]`
`12`	`17`	`}`
`13`	`18`	`]`