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nixpkgs/pkgs/build-support/cc-wrapper/cc-wrapper.sh
Matthew Bauer d180cb9850 cc-wrapper: make machine configuration configurable
It is useful to make these dynamic and not bake them into gcc. This
means we don’t have to rebuild gcc to change these values. Instead, we
will pass cflags to gcc based on platform values. This was already
done hackily for android gcc (which is multi-target), but not for our
own gccs which are single target.

To accomplish this, we need to add a few things:

- add ‘arch’ to cpu
- add NIX_CFLAGS_COMPILE_BEFORE flag (goes before args)
- set -march everywhere
- set mcpu, mfpu, mmode, and mtune based on targetPlatform.gcc flags

cc-wrapper: only set -march when it is in the cpu type

Some architectures don’t have a good mapping of -march. For instance
POWER architecture doesn’t support the -march flag at all!

https://gcc.gnu.org/onlinedocs/gcc/RS_002f6000-and-PowerPC-Options.html#RS_002f6000-and-PowerPC-Options
2019-04-20 20:05:51 -04:00

187 lines
5.5 KiB
Bash

#! @shell@
set -eu -o pipefail +o posix
shopt -s nullglob
if (( "${NIX_DEBUG:-0}" >= 7 )); then
set -x
fi
path_backup="$PATH"
# That @-vars are substituted separately from bash evaluation makes
# shellcheck think this, and others like it, are useless conditionals.
# shellcheck disable=SC2157
if [[ -n "@coreutils_bin@" && -n "@gnugrep_bin@" ]]; then
PATH="@coreutils_bin@/bin:@gnugrep_bin@/bin"
fi
source @out@/nix-support/utils.bash
# Flirting with a layer violation here.
if [ -z "${NIX_BINTOOLS_WRAPPER_@infixSalt@_FLAGS_SET:-}" ]; then
source @bintools@/nix-support/add-flags.sh
fi
# Put this one second so libc ldflags take priority.
if [ -z "${NIX_CC_WRAPPER_@infixSalt@_FLAGS_SET:-}" ]; then
source @out@/nix-support/add-flags.sh
fi
# Parse command line options and set several variables.
# For instance, figure out if linker flags should be passed.
# GCC prints annoying warnings when they are not needed.
dontLink=0
nonFlagArgs=0
# shellcheck disable=SC2193
[[ "@prog@" = *++ ]] && isCpp=1 || isCpp=0
cppInclude=1
expandResponseParams "$@"
declare -i n=0
nParams=${#params[@]}
while (( "$n" < "$nParams" )); do
p=${params[n]}
p2=${params[n+1]:-} # handle `p` being last one
if [ "$p" = -c ]; then
dontLink=1
elif [ "$p" = -S ]; then
dontLink=1
elif [ "$p" = -E ]; then
dontLink=1
elif [ "$p" = -E ]; then
dontLink=1
elif [ "$p" = -M ]; then
dontLink=1
elif [ "$p" = -MM ]; then
dontLink=1
elif [[ "$p" = -x && "$p2" = *-header ]]; then
dontLink=1
elif [[ "$p" = -x && "$p2" = c++* && "$isCpp" = 0 ]]; then
isCpp=1
elif [ "$p" = -nostdlib ]; then
isCpp=-1
elif [ "$p" = -nostdinc ]; then
cppInclude=0
elif [ "$p" = -nostdinc++ ]; then
cppInclude=0
elif [[ "$p" != -?* ]]; then
# A dash alone signifies standard input; it is not a flag
nonFlagArgs=1
fi
n+=1
done
# If we pass a flag like -Wl, then gcc will call the linker unless it
# can figure out that it has to do something else (e.g., because of a
# "-c" flag). So if no non-flag arguments are given, don't pass any
# linker flags. This catches cases like "gcc" (should just print
# "gcc: no input files") and "gcc -v" (should print the version).
if [ "$nonFlagArgs" = 0 ]; then
dontLink=1
fi
# Optionally filter out paths not refering to the store.
if [[ "${NIX_ENFORCE_PURITY:-}" = 1 && -n "$NIX_STORE" ]]; then
rest=()
nParams=${#params[@]}
declare -i n=0
while (( "$n" < "$nParams" )); do
p=${params[n]}
p2=${params[n+1]:-} # handle `p` being last one
if [ "${p:0:3}" = -L/ ] && badPath "${p:2}"; then
skip "${p:2}"
elif [ "$p" = -L ] && badPath "$p2"; then
n+=1; skip "$p2"
elif [ "${p:0:3}" = -I/ ] && badPath "${p:2}"; then
skip "${p:2}"
elif [ "$p" = -I ] && badPath "$p2"; then
n+=1; skip "$p2"
elif [ "$p" = -isystem ] && badPath "$p2"; then
n+=1; skip "$p2"
else
rest+=("$p")
fi
n+=1
done
# Old bash empty array hack
params=(${rest+"${rest[@]}"})
fi
# Clear march/mtune=native -- they bring impurity.
if [ "$NIX_@infixSalt@_ENFORCE_NO_NATIVE" = 1 ]; then
rest=()
# Old bash empty array hack
for p in ${params+"${params[@]}"}; do
if [[ "$p" = -m*=native ]]; then
skip "$p"
else
rest+=("$p")
fi
done
# Old bash empty array hack
params=(${rest+"${rest[@]}"})
fi
if [[ "$isCpp" = 1 ]]; then
if [[ "$cppInclude" = 1 ]]; then
NIX_@infixSalt@_CFLAGS_COMPILE+=" ${NIX_@infixSalt@_CXXSTDLIB_COMPILE:-@default_cxx_stdlib_compile@}"
fi
NIX_@infixSalt@_CFLAGS_LINK+=" $NIX_@infixSalt@_CXXSTDLIB_LINK"
fi
source @out@/nix-support/add-hardening.sh
# Add the flags for the C compiler proper.
extraAfter=($NIX_@infixSalt@_CFLAGS_COMPILE)
extraBefore=(${hardeningCFlags[@]+"${hardeningCFlags[@]}"} $NIX_@infixSalt@_CFLAGS_COMPILE_BEFORE)
if [ "$dontLink" != 1 ]; then
# Add the flags that should only be passed to the compiler when
# linking.
extraAfter+=($NIX_@infixSalt@_CFLAGS_LINK)
# Add the flags that should be passed to the linker (and prevent
# `ld-wrapper' from adding NIX_@infixSalt@_LDFLAGS again).
for i in $NIX_@infixSalt@_LDFLAGS_BEFORE; do
extraBefore+=("-Wl,$i")
done
for i in $NIX_@infixSalt@_LDFLAGS; do
if [ "${i:0:3}" = -L/ ]; then
extraAfter+=("$i")
else
extraAfter+=("-Wl,$i")
fi
done
export NIX_@infixSalt@_LDFLAGS_SET=1
fi
# As a very special hack, if the arguments are just `-v', then don't
# add anything. This is to prevent `gcc -v' (which normally prints
# out the version number and returns exit code 0) from printing out
# `No input files specified' and returning exit code 1.
if [ "$*" = -v ]; then
extraAfter=()
extraBefore=()
fi
# Optionally print debug info.
if (( "${NIX_DEBUG:-0}" >= 1 )); then
# Old bash workaround, see ld-wrapper for explanation.
echo "extra flags before to @prog@:" >&2
printf " %q\n" ${extraBefore+"${extraBefore[@]}"} >&2
echo "original flags to @prog@:" >&2
printf " %q\n" ${params+"${params[@]}"} >&2
echo "extra flags after to @prog@:" >&2
printf " %q\n" ${extraAfter+"${extraAfter[@]}"} >&2
fi
PATH="$path_backup"
# Old bash workaround, see above.
exec @prog@ \
${extraBefore+"${extraBefore[@]}"} \
${params+"${params[@]}"} \
${extraAfter+"${extraAfter[@]}"}