Merge #1134

bors[bot] · Alexhuszagh · web-flow · commit d4b21416c409 · 2022-11-28T14:36:04.000Z
1134: Use a linker script for libstdc++. r=Emilgardis a=Alexhuszagh Use a linker script for `libstdc++.so` since we remove the dylib, to ensure a static build is always used to avoid segfaults at runtime. However, the archive can reference missing symbols present in `libc` or `libgcc`, and itself depends on symbols in `libm`. To ensure these libraries are properly linked when forcing a build against the static `libstdc++`, create a linker script for `libstdc++.so` that links to the static archive, and as needed, all dependencies. Related to #1124. Co-authored-by: Alex Huszagh <ahuszagh@gmail.com>
diff --git a/.changes/1063-1125-1134.json b/.changes/1063-1125-1134.json
@@ -12,7 +12,7 @@
     },
     {
         "type": "fixed",
-        "description": "always link to libc when compiling alpine since static libstdc++ may have undefined references to libc symbols.",
+        "description": "use a linker script for musl libstdc++ to ensure the archive links to libc, libm, and libgcc as needed.",
         "issues": [1124]
     }
 ]
diff --git a/docker/Dockerfile.aarch64-unknown-linux-musl b/docker/Dockerfile.aarch64-unknown-linux-musl
@@ -21,9 +21,7 @@ ENV CROSS_SYSROOT=/usr/local/aarch64-linux-musl
 COPY musl-symlink.sh /
 RUN /musl-symlink.sh $CROSS_SYSROOT aarch64
 
-COPY aarch64-linux-musl-gcc.sh /usr/bin/
-COPY rustc_info.sh /
-
+COPY musl-gcc.sh /usr/bin/"$CROSS_TOOLCHAIN_PREFIX"gcc.sh
 COPY qemu-runner base-runner.sh /
 
 ENV CARGO_TARGET_AARCH64_UNKNOWN_LINUX_MUSL_LINKER="$CROSS_TOOLCHAIN_PREFIX"gcc.sh \
@@ -33,4 +31,5 @@ ENV CARGO_TARGET_AARCH64_UNKNOWN_LINUX_MUSL_LINKER="$CROSS_TOOLCHAIN_PREFIX"gcc.
     CXX_aarch64_unknown_linux_musl="$CROSS_TOOLCHAIN_PREFIX"g++ \
     BINDGEN_EXTRA_CLANG_ARGS_aarch64_unknown_linux_musl="--sysroot=$CROSS_SYSROOT" \
     QEMU_LD_PREFIX="$CROSS_SYSROOT" \
-    RUST_TEST_THREADS=1
+    RUST_TEST_THREADS=1 \
+    CROSS_BUILTINS_PATCHED_MINOR_VERSION=48
diff --git a/docker/Dockerfile.arm-unknown-linux-musleabi b/docker/Dockerfile.arm-unknown-linux-musleabi
@@ -27,9 +27,7 @@ RUN /musl-symlink.sh $CROSS_SYSROOT arm
 
 COPY qemu-runner base-runner.sh /
 
-COPY musl-gcc.sh /usr/bin/"$CROSS_TOOLCHAIN_PREFIX"gcc.sh
-
-ENV CARGO_TARGET_ARM_UNKNOWN_LINUX_MUSLEABI_LINKER="$CROSS_TOOLCHAIN_PREFIX"gcc.sh \
+ENV CARGO_TARGET_ARM_UNKNOWN_LINUX_MUSLEABI_LINKER="$CROSS_TOOLCHAIN_PREFIX"gcc \
     CARGO_TARGET_ARM_UNKNOWN_LINUX_MUSLEABI_RUNNER="/qemu-runner arm" \
     AR_arm_unknown_linux_musleabi="$CROSS_TOOLCHAIN_PREFIX"ar \
     CC_arm_unknown_linux_musleabi="$CROSS_TOOLCHAIN_PREFIX"gcc \
diff --git a/docker/Dockerfile.arm-unknown-linux-musleabihf b/docker/Dockerfile.arm-unknown-linux-musleabihf
@@ -28,9 +28,7 @@ RUN /musl-symlink.sh $CROSS_SYSROOT armhf
 
 COPY qemu-runner base-runner.sh /
 
-COPY musl-gcc.sh /usr/bin/"$CROSS_TOOLCHAIN_PREFIX"gcc.sh
-
-ENV CARGO_TARGET_ARM_UNKNOWN_LINUX_MUSLEABIHF_LINKER="$CROSS_TOOLCHAIN_PREFIX"gcc.sh \
+ENV CARGO_TARGET_ARM_UNKNOWN_LINUX_MUSLEABIHF_LINKER="$CROSS_TOOLCHAIN_PREFIX"gcc \
     CARGO_TARGET_ARM_UNKNOWN_LINUX_MUSLEABIHF_RUNNER="/qemu-runner armhf" \
     AR_arm_unknown_linux_musleabihf="$CROSS_TOOLCHAIN_PREFIX"ar \
     CC_arm_unknown_linux_musleabihf="$CROSS_TOOLCHAIN_PREFIX"gcc \
diff --git a/docker/Dockerfile.armv5te-unknown-linux-musleabi b/docker/Dockerfile.armv5te-unknown-linux-musleabi
@@ -25,16 +25,15 @@ ENV CROSS_SYSROOT=/usr/local/arm-linux-musleabi
 COPY musl-symlink.sh /
 RUN /musl-symlink.sh $CROSS_SYSROOT arm
 
+COPY musl-gcc.sh /usr/bin/"$CROSS_TOOLCHAIN_PREFIX"gcc.sh
 COPY qemu-runner base-runner.sh /
 
-COPY rust-1-65-musl-gcc.sh /usr/bin/"$CROSS_TOOLCHAIN_PREFIX"gcc.sh
-COPY rustc_info.sh /
-
 ENV CARGO_TARGET_ARMV5TE_UNKNOWN_LINUX_MUSLEABI_LINKER="$CROSS_TOOLCHAIN_PREFIX"gcc.sh \
     CARGO_TARGET_ARMV5TE_UNKNOWN_LINUX_MUSLEABI_RUNNER="/qemu-runner arm" \
     AR_armv5te_unknown_linux_musleabi="$CROSS_TOOLCHAIN_PREFIX"ar \
     CC_armv5te_unknown_linux_musleabi="$CROSS_TOOLCHAIN_PREFIX"gcc \
     CXX_armv5te_unknown_linux_musleabi="$CROSS_TOOLCHAIN_PREFIX"g++ \
     BINDGEN_EXTRA_CLANG_ARGS_armv5te_unknown_linux_musleabi="--sysroot=$CROSS_SYSROOT" \
     QEMU_LD_PREFIX="$CROSS_SYSROOT" \
-    RUST_TEST_THREADS=1
+    RUST_TEST_THREADS=1 \
+    CROSS_BUILTINS_PATCHED_MINOR_VERSION=65
diff --git a/docker/Dockerfile.armv7-unknown-linux-musleabi b/docker/Dockerfile.armv7-unknown-linux-musleabi
@@ -28,9 +28,7 @@ RUN /musl-symlink.sh $CROSS_SYSROOT arm
 
 COPY qemu-runner base-runner.sh /
 
-COPY musl-gcc.sh /usr/bin/"$CROSS_TOOLCHAIN_PREFIX"gcc.sh
-
-ENV CARGO_TARGET_ARMV7_UNKNOWN_LINUX_MUSLEABI_LINKER="$CROSS_TOOLCHAIN_PREFIX"gcc.sh \
+ENV CARGO_TARGET_ARMV7_UNKNOWN_LINUX_MUSLEABI_LINKER="$CROSS_TOOLCHAIN_PREFIX"gcc \
     CARGO_TARGET_ARMV7_UNKNOWN_LINUX_MUSLEABI_RUNNER="/qemu-runner armv7" \
     AR_armv7_unknown_linux_musleabi="$CROSS_TOOLCHAIN_PREFIX"ar \
     CC_armv7_unknown_linux_musleabi="$CROSS_TOOLCHAIN_PREFIX"gcc \
diff --git a/docker/Dockerfile.armv7-unknown-linux-musleabihf b/docker/Dockerfile.armv7-unknown-linux-musleabihf
@@ -28,9 +28,7 @@ RUN /musl-symlink.sh $CROSS_SYSROOT armhf
 
 COPY qemu-runner base-runner.sh /
 
-COPY musl-gcc.sh /usr/bin/"$CROSS_TOOLCHAIN_PREFIX"gcc.sh
-
-ENV CARGO_TARGET_ARMV7_UNKNOWN_LINUX_MUSLEABIHF_LINKER="$CROSS_TOOLCHAIN_PREFIX"gcc.sh \
+ENV CARGO_TARGET_ARMV7_UNKNOWN_LINUX_MUSLEABIHF_LINKER="$CROSS_TOOLCHAIN_PREFIX"gcc \
     CARGO_TARGET_ARMV7_UNKNOWN_LINUX_MUSLEABIHF_RUNNER="/qemu-runner armv7hf" \
     AR_armv7_unknown_linux_musleabihf="$CROSS_TOOLCHAIN_PREFIX"ar \
     CC_armv7_unknown_linux_musleabihf="$CROSS_TOOLCHAIN_PREFIX"gcc \
diff --git a/docker/Dockerfile.i586-unknown-linux-musl b/docker/Dockerfile.i586-unknown-linux-musl
@@ -23,9 +23,7 @@ RUN /musl-symlink.sh $CROSS_SYSROOT i386
 
 COPY qemu-runner base-runner.sh /
 
-COPY musl-gcc.sh /usr/bin/"$CROSS_TOOLCHAIN_PREFIX"gcc.sh
-
-ENV CARGO_TARGET_I586_UNKNOWN_LINUX_MUSL_LINKER="$CROSS_TOOLCHAIN_PREFIX"gcc.sh \
+ENV CARGO_TARGET_I586_UNKNOWN_LINUX_MUSL_LINKER="$CROSS_TOOLCHAIN_PREFIX"gcc \
     CARGO_TARGET_I586_UNKNOWN_LINUX_MUSL_RUNNER="/qemu-runner i586" \
     AR_i586_unknown_linux_musl="$CROSS_TOOLCHAIN_PREFIX"ar \
     CC_i586_unknown_linux_musl="$CROSS_TOOLCHAIN_PREFIX"gcc \
diff --git a/docker/Dockerfile.i686-unknown-linux-musl b/docker/Dockerfile.i686-unknown-linux-musl
@@ -23,9 +23,7 @@ RUN /musl-symlink.sh $CROSS_SYSROOT i386
 
 COPY qemu-runner base-runner.sh /
 
-COPY musl-gcc.sh /usr/bin/"$CROSS_TOOLCHAIN_PREFIX"gcc.sh
-
-ENV CARGO_TARGET_I686_UNKNOWN_LINUX_MUSL_LINKER="$CROSS_TOOLCHAIN_PREFIX"gcc.sh \
+ENV CARGO_TARGET_I686_UNKNOWN_LINUX_MUSL_LINKER="$CROSS_TOOLCHAIN_PREFIX"gcc \
     CARGO_TARGET_I686_UNKNOWN_LINUX_MUSL_RUNNER="/qemu-runner i686" \
     AR_i686_unknown_linux_musl="$CROSS_TOOLCHAIN_PREFIX"ar \
     CC_i686_unknown_linux_musl="$CROSS_TOOLCHAIN_PREFIX"gcc \
diff --git a/docker/Dockerfile.mips-unknown-linux-musl b/docker/Dockerfile.mips-unknown-linux-musl
@@ -27,9 +27,7 @@ RUN /musl-symlink.sh $CROSS_SYSROOT mips-sf
 
 COPY qemu-runner base-runner.sh /
 
-COPY musl-gcc.sh /usr/bin/"$CROSS_TOOLCHAIN_PREFIX"gcc.sh
-
-ENV CARGO_TARGET_MIPS_UNKNOWN_LINUX_MUSL_LINKER="$CROSS_TOOLCHAIN_PREFIX"gcc.sh \
+ENV CARGO_TARGET_MIPS_UNKNOWN_LINUX_MUSL_LINKER="$CROSS_TOOLCHAIN_PREFIX"gcc \
     CARGO_TARGET_MIPS_UNKNOWN_LINUX_MUSL_RUNNER="/qemu-runner mips" \
     AR_mips_unknown_linux_musl="$CROSS_TOOLCHAIN_PREFIX"ar \
     CC_mips_unknown_linux_musl="$CROSS_TOOLCHAIN_PREFIX"gcc \
diff --git a/docker/Dockerfile.mips64-unknown-linux-muslabi64 b/docker/Dockerfile.mips64-unknown-linux-muslabi64
@@ -28,9 +28,7 @@ RUN mkdir -p $CROSS_SYSROOT/usr/lib64
 RUN ln -s $CROSS_SYSROOT/usr/lib/libc.so $CROSS_SYSROOT/usr/lib64/libc.so
 RUN ln -s $CROSS_SYSROOT/usr/lib/libc.so.1 $CROSS_SYSROOT/usr/lib64/libc.so.1
 
-COPY rust-1-65-musl-gcc.sh /usr/bin/"$CROSS_TOOLCHAIN_PREFIX"gcc.sh
-COPY rustc_info.sh /
-
+COPY musl-gcc.sh /usr/bin/"$CROSS_TOOLCHAIN_PREFIX"gcc.sh
 COPY qemu-runner base-runner.sh /
 
 ENV CARGO_TARGET_MIPS64_UNKNOWN_LINUX_MUSLABI64_LINKER="$CROSS_TOOLCHAIN_PREFIX"gcc.sh \
@@ -40,4 +38,5 @@ ENV CARGO_TARGET_MIPS64_UNKNOWN_LINUX_MUSLABI64_LINKER="$CROSS_TOOLCHAIN_PREFIX"
     CXX_mips64_unknown_linux_muslabi64="$CROSS_TOOLCHAIN_PREFIX"g++ \
     BINDGEN_EXTRA_CLANG_ARGS_mips64_unknown_linux_muslabi64="--sysroot=$CROSS_SYSROOT" \
     QEMU_LD_PREFIX="$CROSS_SYSROOT" \
-    RUST_TEST_THREADS=1
+    RUST_TEST_THREADS=1 \
+    CROSS_BUILTINS_PATCHED_MINOR_VERSION=65
diff --git a/docker/Dockerfile.mips64el-unknown-linux-muslabi64 b/docker/Dockerfile.mips64el-unknown-linux-muslabi64
@@ -28,9 +28,7 @@ RUN mkdir -p $CROSS_SYSROOT/usr/lib64
 RUN ln -s $CROSS_SYSROOT/usr/lib/libc.so $CROSS_SYSROOT/usr/lib64/libc.so
 RUN ln -s $CROSS_SYSROOT/usr/lib/libc.so.1 $CROSS_SYSROOT/usr/lib64/libc.so.1
 
-COPY rust-1-65-musl-gcc.sh /usr/bin/"$CROSS_TOOLCHAIN_PREFIX"gcc.sh
-COPY rustc_info.sh /
-
+COPY musl-gcc.sh /usr/bin/"$CROSS_TOOLCHAIN_PREFIX"gcc.sh
 COPY qemu-runner base-runner.sh /
 
 ENV CARGO_TARGET_MIPS64EL_UNKNOWN_LINUX_MUSLABI64_LINKER="$CROSS_TOOLCHAIN_PREFIX"gcc.sh \
@@ -40,4 +38,5 @@ ENV CARGO_TARGET_MIPS64EL_UNKNOWN_LINUX_MUSLABI64_LINKER="$CROSS_TOOLCHAIN_PREFI
     CXX_mips64el_unknown_linux_muslabi64="$CROSS_TOOLCHAIN_PREFIX"g++ \
     BINDGEN_EXTRA_CLANG_ARGS_mips64el_unknown_linux_muslabi64="--sysroot=$CROSS_SYSROOT" \
     QEMU_LD_PREFIX="$CROSS_SYSROOT" \
-    RUST_TEST_THREADS=1
+    RUST_TEST_THREADS=1 \
+    CROSS_BUILTINS_PATCHED_MINOR_VERSION=65
diff --git a/docker/Dockerfile.mipsel-unknown-linux-musl b/docker/Dockerfile.mipsel-unknown-linux-musl
@@ -27,9 +27,7 @@ RUN /musl-symlink.sh $CROSS_SYSROOT mipsel-sf
 
 COPY qemu-runner base-runner.sh /
 
-COPY musl-gcc.sh /usr/bin/"$CROSS_TOOLCHAIN_PREFIX"gcc.sh
-
-ENV CARGO_TARGET_MIPSEL_UNKNOWN_LINUX_MUSL_LINKER="$CROSS_TOOLCHAIN_PREFIX"gcc.sh \
+ENV CARGO_TARGET_MIPSEL_UNKNOWN_LINUX_MUSL_LINKER="$CROSS_TOOLCHAIN_PREFIX"gcc \
     CARGO_TARGET_MIPSEL_UNKNOWN_LINUX_MUSL_RUNNER="/qemu-runner mipsel" \
     AR_mipsel_unknown_linux_musl="$CROSS_TOOLCHAIN_PREFIX"ar \
     CC_mipsel_unknown_linux_musl="$CROSS_TOOLCHAIN_PREFIX"gcc \
diff --git a/docker/Dockerfile.x86_64-unknown-linux-musl b/docker/Dockerfile.x86_64-unknown-linux-musl
@@ -23,9 +23,7 @@ RUN /musl-symlink.sh $CROSS_SYSROOT x86_64
 
 COPY qemu-runner base-runner.sh /
 
-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 \
+ENV CARGO_TARGET_X86_64_UNKNOWN_LINUX_MUSL_LINKER="$CROSS_TOOLCHAIN_PREFIX"gcc \
     CARGO_TARGET_X86_64_UNKNOWN_LINUX_MUSL_RUNNER="/qemu-runner x86_64" \
     AR_x86_64_unknown_linux_musl="$CROSS_TOOLCHAIN_PREFIX"ar \
     CC_x86_64_unknown_linux_musl="$CROSS_TOOLCHAIN_PREFIX"gcc \
diff --git a/docker/aarch64-linux-musl-gcc.sh b/docker/aarch64-linux-musl-gcc.sh
diff --git a/docker/musl-gcc.sh b/docker/musl-gcc.sh
@@ -1,20 +1,74 @@
 #!/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.
+# this linker works around missing builtins in older rust versions.
+# we also have custom linker scripts for our static libstdc++ for all versions
+# which is found in `musl-symlink.sh`.
+#
+# for other targets, issues in older versions of compiler-builtins require
+# manually linking to libgcc to compensate for missing builtins.
+# target-specific details include:
+#
+# aarch64-unknown-linux-musl (fixed in 1.48)
+#   https://github.com/rust-lang/compiler-builtins/pull/377
+#
+# armv5te-unknown-linux-musleabi (fixed in 1.65)
+#   missing sync `sync_X_and_fetch`
+#   https://github.com/rust-lang/compiler-builtins/pull/484
+#
+# mips64-unknown-linux-muslabi64, mips64el-unknown-linux-muslabi64  (fixed in 1.65)
+#   missing soft-fp routine `__trunctfsf2`
+#   https://github.com/rust-lang/compiler-builtins/pull/483
 
 set -x
 set -euo pipefail
 
 main() {
-    if [[ $# -eq 0 ]]; then
+    local minor
+    local patched_minor="${CROSS_BUILTINS_PATCHED_MINOR_VERSION:-0}"
+    minor=$(rustc_minor_version)
+
+    if [[ $# -eq 0 ]] || [[ "${minor}" -ge "${patched_minor}" ]]; then
         exec "${CROSS_TOOLCHAIN_PREFIX}"gcc "${@}"
     else
-        exec "${CROSS_TOOLCHAIN_PREFIX}"gcc "${@}" -lc
+        exec "${CROSS_TOOLCHAIN_PREFIX}"gcc "${@}" -lgcc -static-libgcc
+    fi
+}
+
+# FIXME: the rest of the contents of this file can be removed later on,
+# especially after 0.3.0 has been released so we can ensure everyone is
+# using a cross version at least as recent as images requiring the rust
+# versions provided as environment variables. these functions are wrappers
+# around these environment variables for backwards compatibility.
+# https://github.com/cross-rs/cross/issues/1046
+
+# NOTE: this will fail if rustc does not provide version
+# info, which may happen with a custom toolchain.
+rustc_version() {
+    rustc -Vv | grep '^release:' | cut -d ':' -f2
+}
+
+rustc_major_version() {
+    if [[ -z "${CROSS_RUSTC_MAJOR_VERSION:-}" ]]; then
+        CROSS_RUSTC_MAJOR_VERSION=$(rustc_version | cut -d '.' -f1)
+        export CROSS_RUSTC_MAJOR_VERSION
+    fi
+    echo "${CROSS_RUSTC_MAJOR_VERSION}"
+}
+
+rustc_minor_version() {
+    if [[ -z "${CROSS_RUSTC_MINOR_VERSION:-}" ]]; then
+        CROSS_RUSTC_MINOR_VERSION=$(rustc_version | cut -d '.' -f2)
+        export CROSS_RUSTC_MINOR_VERSION
+    fi
+    echo "${CROSS_RUSTC_MINOR_VERSION}"
+}
+
+rustc_patch_version() {
+    if [[ -z "${CROSS_RUSTC_PATCH_VERSION:-}" ]]; then
+        CROSS_RUSTC_PATCH_VERSION=$(rustc_version | cut -d '.' -f3)
+        export CROSS_RUSTC_PATCH_VERSION
     fi
+    echo "${CROSS_RUSTC_PATCH_VERSION}"
 }
 
 main "${@}"
diff --git a/docker/musl-symlink.sh b/docker/musl-symlink.sh
@@ -53,6 +53,25 @@ main() {
     # https://github.com/cross-rs/cross/issues/902
     rm "${sysroot}"/lib/libstdc++.so* || true
 
+    # now, we create a linker script that adds all the required dependencies
+    # because we link to a static libstdc++ to avoid runtime issues and
+    # with the shared libstdc++, we can have missing symbols that are reference
+    # in libstdc++, such as those from libc like `setlocale` and `__cxa_atexit`,
+    # as well as those from libgcc, like `__extendsftf2`. all musl targets
+    # can require symbols from libc, however, only the following are known
+    # to require symbols from libgcc:
+    #   - aarch64-unknown-linux-musl
+    #   - mips64-unknown-linux-muslabi64
+    #   - mips64el-unknown-linux-muslabi64
+    echo '/* cross-rs linker script
+ * this allows us to statically link libstdc++ to avoid segfaults
+ * https://github.com/cross-rs/cross/issues/902
+ */
+GROUP ( libstdc++.a AS_NEEDED( -lgcc -lc -lm ) )
+' > "${sysroot}"/lib/libstdc++.so.6.0.27
+    ln -s libstdc++.so.6.0.27 "${sysroot}"/lib/libstdc++.so.6
+    ln -s libstdc++.so.6.0.27 "${sysroot}"/lib/libstdc++.so
+
     echo "${sysroot}/lib" >> "/etc/ld-musl-${arch}.path"
 
     rm -rf "${0}"
diff --git a/docker/rust-1-65-musl-gcc.sh b/docker/rust-1-65-musl-gcc.sh
diff --git a/docker/rustc_info.sh b/docker/rustc_info.sh

Original file line number	Diff line number	Diff line change
`@@ -12,7 +12,7 @@`
`12`	`12`	`},`
`13`	`13`	`{`
`14`	`14`	`"type": "fixed",`
`15`		`- "description": "always link to libc when compiling alpine since static libstdc++ may have undefined references to libc symbols.",`
	`15`	`+ "description": "use a linker script for musl libstdc++ to ensure the archive links to libc, libm, and libgcc as needed.",`
`16`	`16`	`"issues": [1124]`
`17`	`17`	`}`
`18`	`18`	`]`