afl-clang-lto incomptable with -flto=thin

2 files changed, 10 insertions, 0 deletions

diff --git a/docs/Changelog.md b/docs/Changelog.md
index e85de763..799c13af 100644
--- a/docs/Changelog.md
+++ b/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`
diff --git a/src/afl-cc.c b/src/afl-cc.c
index 19314555..13ca751e 100644
--- a/src/afl-cc.c
+++ b/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;