lix/make/lib/compile-c.sh

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. $stdenv/setup
mainName=$(basename $main | cut -c34-)
echo "compiling \`$mainName'..."
# Turn $localIncludes into an array.
localIncludes=($localIncludes)
# Determine how many `..' levels appear in the header file references.
# E.g., if there is some reference `../../foo.h', then we have to
# insert two extra levels in the directory structure, so that `a.c' is
# stored at `dotdot/dotdot/a.c', and a reference from it to
# `../../foo.h' resolves to `dotdot/dotdot/../../foo.h' == `foo.h'.
n=0
maxDepth=0
for ((n = 0; n < ${#localIncludes[*]}; n += 2)); do
target=${localIncludes[$((n + 1))]}
# Split the target name into path components using some IFS magic.
savedIFS="$IFS"
IFS=/
components=($target)
depth=0
for ((m = 0; m < ${#components[*]}; m++)); do
c=${components[m]}
if test "$c" = ".."; then
depth=$((depth + 1))
fi
done
IFS="$savedIFS"
if test $depth -gt $maxDepth; then
maxDepth=$depth;
fi
done
# Create the extra levels in the directory hierarchy.
prefix=
for ((n = 0; n < maxDepth; n++)); do
prefix="dotdot/$prefix"
done
# Create symlinks to the header files.
for ((n = 0; n < ${#localIncludes[*]}; n += 2)); do
source=${localIncludes[n]}
target=${localIncludes[$((n + 1))]}
# Create missing directories. We use IFS magic to split the path
# into path components.
savedIFS="$IFS"
IFS=/
components=($prefix$target)
fullPath=(.)
for ((m = 0; m < ${#components[*]} - 1; m++)); do
fullPath=("${fullPath[@]}" ${components[m]})
if ! test -d "${fullPath[*]}"; then
mkdir "${fullPath[*]}"
fi
done
IFS="$savedIFS"
ln -sf $source $prefix$target
done
# Create a symlink to the main file.
if ! test "$(readlink $prefix$mainName)" = $main; then
ln -s $main $prefix$mainName
fi
mkdir $out
test "$prefix" && cd $prefix
* A primitive operation `dependencyClosure' to do automatic dependency determination (e.g., finding the header files dependencies of a C file) in Nix low-level builds automatically. For instance, in the function `compileC' in make/lib/default.nix, we find the header file dependencies of C file `main' as follows: localIncludes = dependencyClosure { scanner = file: import (findIncludes { inherit file; }); startSet = [main]; }; The function works by "growing" the set of dependencies, starting with the set `startSet', and calling the function `scanner' for each file to get its dependencies (which should yield a list of strings representing relative paths). For instance, when `scanner' is called on a file `foo.c' that includes the line #include "../bar/fnord.h" then `scanner' should yield ["../bar/fnord.h"]. This list of dependencies is absolutised relative to the including file and added to the set of dependencies. The process continues until no more dependencies are found (hence its a closure). `dependencyClosure' yields a list that contains in alternation a dependency, and its relative path to the directory of the start file, e.g., [ /bla/bla/foo.c "foo.c" /bla/bar/fnord.h "../bar/fnord.h" ] These relative paths are necessary for the builder that compiles foo.c to reconstruct the relative directory structure expected by foo.c. The advantage of `dependencyClosure' over the old approach (using the impure `__currentTime') is that it's completely pure, and more efficient because it only rescans for dependencies (i.e., by building the derivations yielded by `scanner') if sources have actually changed. The old approach rescanned every time.
2005-08-14 12:38:47 +00:00
ls -l
gcc -Wall $cFlags -c $mainName -o $out/$mainName.o