From: Anders Björklund <anders@itension.se>
Date: Sun, 29 Nov 2015 12:52:21 +0000 (+0100)
Subject: Improve debuginfo cwd when using -fdebug-prefix-map
X-Git-Tag: v3.3~117
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=020045d73ccf9b16656837027efab409d9de435d;p=thirdparty%2Fccache.git

Improve debuginfo cwd when using -fdebug-prefix-map

Support the -fdebug-prefix-map option, for relocating the debuginfo
current working directory (cwd) as recorded with CCACHE_HASHDIR.
This can be used in connection with CCACHE_BASEDIR, to get cache hits
even when generating debuginfo: the base directory can be mapped.
---

diff --git a/MANUAL.txt b/MANUAL.txt
index 9852cb372..aae6d2aeb 100644
--- a/MANUAL.txt
+++ b/MANUAL.txt
@@ -242,6 +242,10 @@ setting key. Boolean options are indicated with ``[boolean]''
     directory. If set to the empty string (which is the default), no rewriting
     is done. See also the discussion under
     <<_compiling_in_different_directories,COMPILING IN DIFFERENT DIRECTORIES>>.
+    If using GCC*, you might want to look into the *-fdebug-prefix-map* option
+    for relocating debug info to a common prefix (mapping prefix with old=new).
+
+    * or newer versions of Clang, see: http://reviews.llvm.org/rL250094
 
 *cache_dir* (*CCACHE_DIR*)::
 
diff --git a/ccache.c b/ccache.c
index 14df68260..c9d87dd71 100644
--- a/ccache.c
+++ b/ccache.c
@@ -189,6 +189,9 @@ static bool generating_dependencies;
 /* is gcc being asked to output coverage? */
 static bool generating_coverage;
 
+/* relocating debuginfo, in the format old=new */
+static char *debug_prefix_map = NULL;
+
 /* is gcc being asked to output coverage data (.gcda) at runtime? */
 static bool profile_arcs;
 
@@ -1488,6 +1491,23 @@ calculate_common_hash(struct args *args, struct mdfour *hash)
 	/* Possibly hash the current working directory. */
 	if (conf->hash_dir) {
 		char *cwd = gnu_getcwd();
+		if (debug_prefix_map) {
+			char *map = debug_prefix_map;
+			char *sep = strchr(map, '=');
+			char *dir, *old, *new;
+			if (sep) {
+				old = x_strndup(map, sep - map);
+				new = x_strdup(sep + 1);
+				cc_log("Relocating debuginfo cwd %s, from %s to %s", cwd, old, new);
+				if (str_startswith(cwd, old)) {
+					dir = format("%s%s", new, cwd + strlen(old));
+					free(cwd);
+					cwd = dir;
+				}
+				free(old);
+				free(new);
+			}
+		}
 		if (cwd) {
 			hash_delimiter(hash, "cwd");
 			hash_string(hash, cwd);
@@ -2186,6 +2206,11 @@ cc_process_args(struct args *args, struct args **preprocessor_args,
 			args_add(stripped_args, argv[i]);
 			continue;
 		}
+		if (str_startswith(argv[i], "-fdebug-prefix-map=")) {
+			debug_prefix_map = x_strdup(argv[i] + 19);
+			args_add(stripped_args, argv[i]);
+			continue;
+		}
 
 		/* Debugging is handled specially, so that we know if we can strip line
 		 * number info. */
@@ -3006,6 +3031,7 @@ cc_reset(void)
 	free(primary_config_path); primary_config_path = NULL;
 	free(secondary_config_path); secondary_config_path = NULL;
 	free(current_working_dir); current_working_dir = NULL;
+	free(debug_prefix_map); debug_prefix_map = NULL;
 	free(profile_dir); profile_dir = NULL;
 	free(included_pch_file); included_pch_file = NULL;
 	args_free(orig_args); orig_args = NULL;