afl-clang-lto incomptable with -flto=thin

docs/Changelog.md

@@ -13,6 +13,7 @@
   - afl-cc:
     - new env `AFL_LLVM_LTO_SKIPINIT` to support the AFL++ based WASM
       (https://github.com/fgsect/WAFL) project
+    - error and print help if afl-clan-lto is used with lto=thin
   - afl-showmap:
     - added custom mutator post_process and send support
     - add `-I filelist` option, an alternative to `-i in_dir`

src/afl-cc.c

@@ -853,6 +853,15 @@ static void edit_params(u32 argc, char **argv, char **envp) {
 
     if (cur[0] != '-') { non_dash = 1; }
     if (!strncmp(cur, "--afl", 5)) continue;
+
+    if (lto_mode && !strncmp(cur, "-flto=thin", 10)) {
+
+      FATAL(
+          "afl-clang-lto cannot work with -flto=thin. Switch to -flto=full or "
+          "use afl-clang-fast!");
+
+    }
+
     if (lto_mode && !strncmp(cur, "-fuse-ld=", 9)) continue;
     if (lto_mode && !strncmp(cur, "--ld-path=", 10)) continue;
     if (!strncmp(cur, "-fno-unroll", 11)) continue;