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| -rwxr-xr-x | bin/ldev | 232 |
1 files changed, 232 insertions, 0 deletions
diff --git a/bin/ldev b/bin/ldev new file mode 100755 index 0000000..e113c7c --- /dev/null +++ b/bin/ldev @@ -0,0 +1,232 @@ +#!/bin/sh +set -eu + + +usage() { + cat <<-'EOF' + Usage: + ldev deps FILE... + ldev -h + EOF +} + +help() { + cat <<-'EOF' + + + Options: + -h, --help show this message + + FILE toplevel entrypoint file + + + Given a list of C FILEs, generate the Makefile dependencies + between them. + + We have 2 types of object files: + - .o: plain object files; + - .to: compiled with -DTEST so it can expose its embedded unit + tests; + + We also have 1 aggregate file: + - .xa: an e**x**ecutable **a**rchive, made with ar(1), that + includes all the .o dependencies required for linking, so that + one can have only the archive as the linker input, i.e. + `cc -o example.bin example.xa`. This way we don't need + separate targets for each executable, and we can instead deal + separately with dependencies and linking, but without specific + file listing for each case. We use an ar-chive to exploit the + fact that a) it can replace existing files with the same name + and b) the $? macro in make(1) gives us all the out-of-date + dependencies, so our rule in the Makefile is usually a simple + `$(AR) $(ARFLAGS) $@ $?`. This way each .xa file lists its + dependency separately, and the building of the .xa file is + taken care of, in the same way that the linkage into an + executable is also taken care of. For running unit tests, we + include as a dependency of "$NAME.xa" the "$NAME.to" file, + which is the object code of "$NAME.c" compiled with the -DTEST + flag. This exposes a main() function for running unit tests. + + Also in order to run the unit tests without having to relink + them on each run, we have: + - .bin-check: a dedicated virtual target that does nothing but + execute the tests. In order to assert the binaries exist, + each "$NAME.bin-check" virtual target depends on the + equivalent "$NAME.check" physical target. + + There are 2 types of dependencies that are generated: + 1. self dependencies; + 2. inter dependencies. + + The self dependencies are the ones across different + manifestations of the same file so all derived assets are + correctly kept up-to-date: + - $NAME.o $NAME.to: $NAME.h + + As the .SUFFIXES rule already covers the dependency to the + orinal $NAME.c file, all we do is say that whenever the public + interface of these binaries change, they need to be + recompiled; + + - $NAME.xa: $NAME.to + + We make sure to include in each executable archive (.xa) file + its own binary with unit tests. We include the "depN.o" + dependencies later; + + - $NAME.bin-check: $NAME.bin + + Enforce that the binary exists before we run them. + + After we establish the self dependencies, we scrub each file's + content looking for `#include "..."` lines that denote + dependency to other C file. Once we do that we'll have: + - $NAME.o $NAME.to: dep1.h dep2.h ... depN.h + + We'll recompile our file when its public header changes. When + only the body of the code changes we don't recompile, only + later relink; + + - $NAME.xa: dep1.o dep2.o ... depN.o + + Make sure to include all required dependencies in the + $NAME.bin binary so that the later linking works properly. + + So if we have file1.c, file2.c and file3.c with their respective + headers, where file2.c and file3.c depend of file1.c, i.e. they + have `#include "file.h"` in their code, and file3.c depend of + file2.c, the expected output is: + + file1.o file1.to: file1.h + file2.o file2.to: file2.h + file3.o file3.to: file3.h + + file1.xa: file1.to + file2.xa: file2.to + file3.xa: file3.to + + file1.bin-check: file1.bin + file2.bin-check: file2.bin + file3.bin-check: file3.bin + + + file1.o file1.to: + file2.o file2.to: file1.h + file3.o file3.to: file1.h file2.h + + file1.xa: + file2.xa: file1.o + file3.xa: file1.o file2.o + + This ensures that only the minimal amount of files need to get + recompiled, but no less. + + + Examples: + + Get deps for all files in 'src/' but 'src/main.c': + + $ sh tools/cdeps.sh `find src/*.c -not -name 'main.c'` + + + Emit dependencies for all C files in a Git repository: + + $ sh tools/cdeps.sh `git ls-files | grep '\.c$'` + EOF +} + + +for flag in "$@"; do + case "$flag" in + (--) + break + ;; + (--help) + usage + help + exit + ;; + (*) + ;; + esac +done + +while getopts 'h' flag; do + case "$flag" in + (h) + usage + help + exit + ;; + (*) + usage >&2 + exit 2 + ;; + esac +done +shift $((OPTIND - 1)) +shift + +FILE="${1:-}" +eval "$(assert-arg "$FILE" 'FILE')" + + + +each_f() { + fn="$1" + shift + for file in "$@"; do + f="${file%.c}" + "$fn" "$f" + done + printf '\n' +} + +self_header_deps() { + printf '%s.o\t%s.to:\t%s.h\n' "$1" "$1" "$1" +} + +self_xa_deps() { + printf '%s.xa:\t%s.to\n' "$1" "$1" +} + +self_bincheck_deps() { + printf '%s.bin-check:\t%s.bin\n' "$1" "$1" +} + +deps_for() { + ext="$2" + for file in $(awk -F'"' '/^#include "/ { print $2 }' "$1.c"); do + if [ "$file" = 'config.h' ]; then + continue + fi + if [ "$(basename "$file")" = 'tests-lib.h' ]; then + continue + fi + f="$(dirname "$1")/$file" + if [ "$f" = "$1.h" ]; then + continue + fi + printf '%s\n' "${f%.h}$2" + done +} + +rebuild_deps() { + printf '\n' + printf '%s.o\t%s.to:' "$1" "$1" + printf ' %s' $(deps_for "$1" .h) | sed 's| *$||' +} + +archive_deps() { + printf '\n' + printf '%s.xa:' "$1" + printf ' %s' $(deps_for "$1" .o) | sed 's| *$||' +} + + +each_f self_header_deps "$@" +each_f self_xa_deps "$@" +each_f self_bincheck_deps "$@" + +each_f rebuild_deps "$@" +each_f archive_deps "$@" |