nixpkgs/pkgs/build-support/rust/build-rust-crate/build-crate.nix
Andreas Rammhold 1b748554d5
buildRustCrate: add lib output
This cuts down the dependency tree on some rust builds where a crate not
just exposes a binary but also a library. `$out/lib` contained a bunch
of extra support files that among other information carry linker flags
(including the full path to link-time dependencies). Worst case this led
to some binary outputs depending on the full build closure of rust
crates.

Moving all the `$out/lib` files to `$lib/lib` solves this nicely.

`lib` might be a bit weird here as they are most of the time just rlib
files (rust libraries). Those are essential only required during
compilation but they can also be shared objects (like with traditional
C-style packages). Which is why I went with `lib` for the new output.

One of the caveats we are running into here is that we do not (always)
know ahead of time of a crate produces just a library or just a binary.
Cargo allows for some ambiguity regarding whether or not a crate
provides one, two, … binaries and libraries as it's outputs. Ideally we
would be able to rely on the `crateType` entirely but so far that isn't
the case. More work on that area might show how difficult that actually
is.
2019-11-26 15:05:01 +01:00

172 lines
5.9 KiB
Nix

{ lib, stdenv, echo_build_heading, noisily, makeDeps }:
{ crateName,
dependencies,
crateFeatures, crateRenames, libName, release, libPath,
crateType, metadata, crateBin, hasCrateBin,
extraRustcOpts, verbose, colors }:
let
deps = makeDeps dependencies crateRenames;
rustcOpts =
lib.lists.foldl' (opts: opt: opts + " " + opt)
(if release then "-C opt-level=3" else "-C debuginfo=2")
(["-C codegen-units=$NIX_BUILD_CORES"] ++ extraRustcOpts);
rustcMeta = "-C metadata=${metadata} -C extra-filename=-${metadata}";
# Some platforms have different names for rustc.
rustPlatform =
with stdenv.hostPlatform.parsed;
let cpu_ = if cpu.name == "armv7a" then "armv7"
else cpu.name;
vendor_ = vendor.name;
kernel_ = kernel.name;
abi_ = abi.name;
in
"${cpu_}-${vendor_}-${kernel_}-${abi_}";
in ''
runHook preBuild
norm=""
bold=""
green=""
boldgreen=""
if [[ "${colors}" == "always" ]]; then
norm="$(printf '\033[0m')" #returns to "normal"
bold="$(printf '\033[0;1m')" #set bold
green="$(printf '\033[0;32m')" #set green
boldgreen="$(printf '\033[0;1;32m')" #set bold, and set green.
fi
${echo_build_heading colors}
${noisily colors verbose}
build_lib() {
lib_src=$1
echo_build_heading $lib_src ${libName}
noisily rustc --crate-name $CRATE_NAME $lib_src \
${lib.strings.concatStrings (map (x: " --crate-type ${x}") crateType)} \
${rustcOpts} ${rustcMeta} ${crateFeatures} --out-dir target/lib \
--emit=dep-info,link -L dependency=target/deps ${deps} --cap-lints allow \
$BUILD_OUT_DIR $EXTRA_BUILD $EXTRA_FEATURES --color ${colors}
EXTRA_LIB=" --extern $CRATE_NAME=target/lib/lib$CRATE_NAME-${metadata}.rlib"
if [ -e target/deps/lib$CRATE_NAME-${metadata}${stdenv.hostPlatform.extensions.sharedLibrary} ]; then
EXTRA_LIB="$EXTRA_LIB --extern $CRATE_NAME=target/lib/lib$CRATE_NAME-${metadata}${stdenv.hostPlatform.extensions.sharedLibrary}"
fi
}
build_bin() {
crate_name=$1
crate_name_=$(echo $crate_name | sed -e "s/-/_/g")
main_file=""
if [[ ! -z $2 ]]; then
main_file=$2
fi
echo_build_heading $@
noisily rustc --crate-name $crate_name_ $main_file --crate-type bin ${rustcOpts}\
${crateFeatures} --out-dir target/bin --emit=dep-info,link -L dependency=target/deps \
$LINK ${deps}$EXTRA_LIB --cap-lints allow \
$BUILD_OUT_DIR $EXTRA_BUILD $EXTRA_FEATURES --color ${colors} \
${if stdenv.hostPlatform != stdenv.buildPlatform then "--target ${rustPlatform} -C linker=${stdenv.hostPlatform.config}-gcc" else ""}
if [ "$crate_name_" != "$crate_name" ]; then
mv target/bin/$crate_name_ target/bin/$crate_name
fi
}
EXTRA_LIB=""
CRATE_NAME=$(echo ${libName} | sed -e "s/-/_/g")
if [[ -e target/link_ ]]; then
EXTRA_BUILD="$(cat target/link_) $EXTRA_BUILD"
fi
if [[ -e "${libPath}" ]]; then
build_lib ${libPath}
elif [[ -e src/lib.rs ]]; then
build_lib src/lib.rs
elif [[ -e src/${libName}.rs ]]; then
build_lib src/${libName}.rs
fi
echo "$EXTRA_LINK_SEARCH" | while read i; do
if [[ ! -z "$i" ]]; then
for library in $i; do
echo "-L $library" >> target/link
L=$(echo $library | sed -e "s#$(pwd)/target/build#$lib/lib#")
echo "-L $L" >> target/link.final
done
fi
done
echo "$EXTRA_LINK" | while read i; do
if [[ ! -z "$i" ]]; then
for library in $i; do
echo "-l $library" >> target/link
echo "-l $library" >> target/link.final
done
fi
done
if [[ -e target/link ]]; then
sort -u target/link.final > target/link.final.sorted
mv target/link.final.sorted target/link.final
sort -u target/link > target/link.sorted
mv target/link.sorted target/link
tr '\n' ' ' < target/link > target/link_
LINK=$(cat target/link_)
fi
${lib.optionalString (crateBin != "") ''
printf "%s\n" "${crateBin}" | head -n1 | tr -s ',' '\n' | while read -r BIN_NAME BIN_PATH; do
mkdir -p target/bin
# filter empty entries / empty "lines"
if [[ -z "$BIN_NAME" ]]; then
continue
fi
if [[ -z "$BIN_PATH" ]]; then
# heuristic to "guess" the correct source file as found in cargo:
# https://github.com/rust-lang/cargo/blob/90fc9f620190d5fa3c80b0c8c65a1e1361e6b8ae/src/cargo/util/toml/targets.rs#L308-L325
# the first two cases are the "new" default IIRC
BIN_NAME_=$(echo $BIN_NAME | sed -e 's/-/_/g')
FILES=( "src/bin/$BIN_NAME.rs" "src/bin/$BIN_NAME/main.rs" "src/bin/$BIN_NAME_.rs" "src/bin/$BIN_NAME_/main.rs" "src/bin/main.rs" "src/main.rs" )
if ! [ -e "${libPath}" -o -e src/lib.rs -o -e "src/${libName}.rs" ]; then
# if this is not a library the following path is also valid
FILES=( "src/$BIN_NAME.rs" "src/$BIN_NAME_.rs" "''${FILES[@]}" )
fi
for file in "''${FILES[@]}";
do
echo "checking file $file"
# first file that exists wins
if [[ -e "$file" ]]; then
BIN_PATH="$file"
break
fi
done
if [[ -z "$BIN_PATH" ]]; then
echo "failed to find file for binary target: $BIN_NAME" >&2
exit 1
fi
fi
build_bin "$BIN_NAME" "$BIN_PATH"
done
''}
${lib.optionalString (crateBin == "" && !hasCrateBin) ''
if [[ -e src/main.rs ]]; then
mkdir -p target/bin
build_bin ${crateName} src/main.rs
fi
for i in src/bin/*.rs; do #*/
mkdir -p target/bin
build_bin "$(basename $i .rs)" "$i"
done
''}
# Remove object files to avoid "wrong ELF type"
find target -type f -name "*.o" -print0 | xargs -0 rm -f
runHook postBuild
''