Replace the nm symbol check with a Rust implementation

.github/workflows/main.yaml

@@ -119,7 +119,6 @@ jobs:
         rustup update "$channel" --no-self-update
         rustup default "$channel"
         rustup target add "${{ matrix.target }}"
-        rustup component add llvm-tools-preview
     - uses: taiki-e/install-action@nextest
     - uses: Swatinem/rust-cache@v2
       with:

Cargo.toml

@@ -6,6 +6,7 @@ members = [
     "crates/libm-macros",
     "crates/musl-math-sys",
     "crates/panic-handler",
+    "crates/symbol-check",
     "crates/util",
     "libm",
     "libm-test",

ci/run.sh

@@ -47,87 +47,25 @@ else
     fi
 fi
 
-
-declare -a rlib_paths
-
-# Set the `rlib_paths` global array to a list of all compiler-builtins rlibs
-update_rlib_paths() {
-    if [ -d /builtins-target ]; then
-        rlib_paths=( /builtins-target/"${target}"/debug/deps/libcompiler_builtins-*.rlib )
-    else
-        rlib_paths=( target/"${target}"/debug/deps/libcompiler_builtins-*.rlib )
-    fi
-}
-
-# Remove any existing artifacts from previous tests that don't set #![compiler_builtins]
-update_rlib_paths
-rm -f "${rlib_paths[@]}"
-
-cargo build -p compiler_builtins --target "$target"
-cargo build -p compiler_builtins --target "$target" --release
-cargo build -p compiler_builtins --target "$target" --features c
-cargo build -p compiler_builtins --target "$target" --features c --release
-cargo build -p compiler_builtins --target "$target" --features no-asm
-cargo build -p compiler_builtins --target "$target" --features no-asm --release
-cargo build -p compiler_builtins --target "$target" --features no-f16-f128
-cargo build -p compiler_builtins --target "$target" --features no-f16-f128 --release
-
-PREFIX=${target//unknown-/}-
-case "$target" in
-    armv7-*)
-        PREFIX=arm-linux-gnueabihf-
-        ;;
-    thumb*)
-        PREFIX=arm-none-eabi-
-        ;;
-    *86*-*)
-        PREFIX=
-        ;;
-esac
-
-NM=$(find "$(rustc --print sysroot)" \( -name llvm-nm -o -name llvm-nm.exe \) )
-if [ "$NM" = "" ]; then
-  NM="${PREFIX}nm"
-fi
-
-# i686-pc-windows-gnu tools have a dependency on some DLLs, so run it with
-# rustup run to ensure that those are in PATH.
-TOOLCHAIN="$(rustup show active-toolchain | sed 's/ (default)//')"
-if [[ "$TOOLCHAIN" == *i686-pc-windows-gnu ]]; then
-  NM="rustup run $TOOLCHAIN $NM"
-fi
-
-# Look out for duplicated symbols when we include the compiler-rt (C) implementation
-update_rlib_paths
-for rlib in "${rlib_paths[@]}"; do
-    set +x
-    echo "================================================================"
-    echo "checking $rlib for duplicate symbols"
-    echo "================================================================"
-    set -x
-
-    duplicates_found=0
-
-    # NOTE On i586, It's normal that the get_pc_thunk symbol appears several
-    # times so ignore it
-    $NM -g --defined-only "$rlib" 2>&1 |
-      sort |
-      uniq -d |
-      grep -v __x86.get_pc_thunk --quiet |
-      grep 'T __' && duplicates_found=1
-
-    if [ "$duplicates_found" != 0 ]; then
-        echo "error: found duplicate symbols"
-        exit 1
-    else
-        echo "success; no duplicate symbols found"
-    fi
-done
-
-rm -f "${rlib_paths[@]}"
+# Ensure there are no duplicate symbols or references to `core` when
+# `compiler-builtins` is built with various features.
+symcheck=(cargo run -p symbol-check --release)
+[[ "$target" = "wasm"* ]] && symcheck+=(--features wasm)
+symcheck+=(-- build-and-check)
+
+"${symcheck[@]}" -p compiler_builtins --target "$target"
+"${symcheck[@]}" -p compiler_builtins --target "$target" --release
+"${symcheck[@]}" -p compiler_builtins --target "$target" --features c
+"${symcheck[@]}" -p compiler_builtins --target "$target" --features c --release
+"${symcheck[@]}" -p compiler_builtins --target "$target" --features no-asm
+"${symcheck[@]}" -p compiler_builtins --target "$target" --features no-asm --release
+"${symcheck[@]}" -p compiler_builtins --target "$target" --features no-f16-f128
+"${symcheck[@]}" -p compiler_builtins --target "$target" --features no-f16-f128 --release
 
 build_intrinsics_test() {
-    cargo build \
+    # Mostly we want to check that `cargo build` works, but we also go via
+    # symcheck here to see if any duplicates sneak in somehow.
+    "${symcheck[@]}" \
         --target "$target" --verbose \
         --manifest-path builtins-test-intrinsics/Cargo.toml "$@"
 }
@@ -143,35 +81,6 @@ build_intrinsics_test --features c --release
 CARGO_PROFILE_DEV_LTO=true build_intrinsics_test
 CARGO_PROFILE_RELEASE_LTO=true build_intrinsics_test --release
 
-# Ensure no references to any symbols from core
-update_rlib_paths
-for rlib in "${rlib_paths[@]}"; do
-    set +x
-    echo "================================================================"
-    echo "checking $rlib for references to core"
-    echo "================================================================"
-    set -x
-
-    tmpdir="${CARGO_TARGET_DIR:-target}/tmp"
-    test -d "$tmpdir" || mkdir "$tmpdir"
-    defined="$tmpdir/defined_symbols.txt"
-    undefined="$tmpdir/defined_symbols.txt"
-
-    $NM --quiet -U "$rlib" | grep 'T _ZN4core' | awk '{print $3}' | sort | uniq > "$defined"
-    $NM --quiet -u "$rlib" | grep 'U _ZN4core' | awk '{print $2}' | sort | uniq > "$undefined"
-    grep_has_results=0
-    grep -v -F -x -f "$defined" "$undefined" && grep_has_results=1
-
-    if [ "$target" = "powerpc64-unknown-linux-gnu" ]; then
-        echo "FIXME: powerpc64 fails these tests"
-    elif [ "$grep_has_results" != 0 ]; then
-        echo "error: found unexpected references to core"
-        exit 1
-    else
-        echo "success; no references to core found"
-    fi
-done
-
 # Test libm
 
 # Make sure a simple build works

compiler-builtins/build.rs

@@ -555,7 +555,6 @@ mod c {
 
         if (target.arch == "aarch64" || target.arch == "arm64ec") && consider_float_intrinsics {
             sources.extend(&[
-                ("__comparetf2", "comparetf2.c"),
                 ("__fe_getround", "fp_mode.c"),
                 ("__fe_raise_inexact", "fp_mode.c"),
             ]);
@@ -570,11 +569,11 @@ mod c {
         }
 
         if target.arch == "mips64" {
-            sources.extend(&[("__netf2", "comparetf2.c"), ("__fe_getround", "fp_mode.c")]);
+            sources.extend(&[("__fe_getround", "fp_mode.c")]);
         }
 
         if target.arch == "loongarch64" {
-            sources.extend(&[("__netf2", "comparetf2.c"), ("__fe_getround", "fp_mode.c")]);
+            sources.extend(&[("__fe_getround", "fp_mode.c")]);
         }
 
         // Remove the assembly implementations that won't compile for the target

crates/symbol-check/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "symbol-check"
+version = "0.1.0"
+edition = "2024"
+publish = false
+
+[dependencies]
+# FIXME: used as a git dependency since the latest release does not support wasm
+object = { git = "https://github.com/gimli-rs/object.git", rev = "013fac75da56a684377af4151b8164b78c1790e0" }
+serde_json = "1.0.140"
+
+[features]
+wasm = ["object/wasm"]