Makefile.base

# Common stuff for makefiles, like compiler and flags

# Allow the use of advanced globs in paths
SHELL := /bin/bash -O extglob -O globstar -c

# GCC and ld by default
# Clang is supported in the sense that setting CC=clang LD=ld.lld works,
# but performance may or may not be the same, it's mostly useful for -Weverything
CC ?= gcc
LD ?= ld

# C11, latest POSIX with GNU extensions (unfortunately)
CFLAGS += -std=c11 -D_POSIX_C_SOURCE=200809L -D_GNU_SOURCE

# Max optimizations
CFLAGS += -O2
CFLAGS += -march=native
CFLAGS += -flto

ifeq (, $(findstring clang,$(CC)))
# Allow LTO shared objects to also be linked without LTO if needed
CFLAGS += -ffat-lto-objects
endif

# Required
CFLAGS += -fPIC

# Don't emit unneeded stuff in the binary
CFLAGS += -fno-unwind-tables -fno-asynchronous-unwind-tables

# Don't protect the stack, the code is verified
# NOTE: This is an easy way to change the binary a little bit in case some unrelated change causes the hot path to be slower
CFLAGS += -fno-stack-protector

# Good warnings, and make them fatal errors to avoid walls of output for minor mistakes
CFLAGS += -Wall -Wextra -Werror -pedantic -Wshadow -Wstrict-aliasing -Wpadded -Wfatal-errors

ifneq (, $(findstring clang,$(CC)))
# All the warnings!
CFLAGS += -Weverything
# ...except this one, somehow clang thinks -nostdinc is not actually used
CFLAGS += -Wno-unused-command-line-argument
# ...and also this one, because -Wpacked warns about "unnecessary" uses but this is by definition arch-dependent
CFLAGS += -Wno-packed
endif

# Debug log
# CFLAGS += -DDEBUG_LEVEL=1