Use -fmacro-prefix-map to strip build path

This commit matches sway's 2dc4978d8af326c310057ca8fd22a4c7f5d09335.

To help ensure a reproducible build (when debug info is disabled),
the meson build script now uses the -fmacro-prefix-map command line
argument supported by GCC to strip the build-path dependent bytes
of each __FILE__ string used by wlr_log and related functions.

A rather ugly algorithm is used to compute the relative path between
the build and source folders, because meson has no specific function
for this.

When the compiler does not support -fmacro-prefix-map, fall back
to shifting the start of each __FILE__ string by the length of the
relative path to the source directory.

1 files changed, 0 insertions, 17 deletions

diff --git a/util/log.c b/util/log.c
index 2f4ed86d..25629e05 100644
--- a/util/log.c
+++ b/util/log.c
@@ -81,23 +81,6 @@ void _wlr_log(enum wlr_log_importance verbosity, const char *fmt, ...) {
 	va_end(args);
 }
 
-// strips the path prefix from filepath
-// will try to strip WLR_SRC_DIR as well as a relative src dir
-// e.g. '/src/build/wlroots/backend/wayland/backend.c' and
-// '../backend/wayland/backend.c' will both be stripped to
-// 'backend/wayland/backend.c'
-const char *_wlr_strip_path(const char *filepath) {
-	static int srclen = sizeof(WLR_SRC_DIR);
-	if (strstr(filepath, WLR_SRC_DIR) == filepath) {
-		filepath += srclen;
-	} else if (*filepath == '.') {
-		while (*filepath == '.' || *filepath == '/') {
-			++filepath;
-		}
-	}
-	return filepath;
-}
-
 enum wlr_log_importance wlr_log_get_verbosity(void) {
 	return log_importance;
 }