Add --libafl arg in libafl_cc and enable it for fuzzbench (#466)

fuzzers/fuzzbench/Makefile

@@ -12,7 +12,7 @@ target/release/libafl_cxx: src/* src/bin/*
 target/release/libafl_cc: target/release/libafl_cxx
 
 fuzz.o: fuzz.c target/release/libafl_cc
-	target/release/libafl_cc -O3 -c $^ -o $@
+	target/release/libafl_cc --libafl-no-link -O3 -c $^ -o $@
 
 fuzzer: target/release/libafl_cxx fuzz.o
 	# Build the fuzzer compiler
@@ -20,6 +20,7 @@ fuzzer: target/release/libafl_cxx fuzz.o
 
 	# Build the harness	
 	target/release/libafl_cxx \
+	  --libafl \
 		fuzz.o \
 		-o $(FUZZER_NAME) \
 		-lm -lz

fuzzers/fuzzbench/src/bin/libafl_cc.rs

@@ -20,6 +20,8 @@ pub fn main() {
             .cpp(is_cpp)
             // silence the compiler wrapper output, needed for some configure scripts.
             .silence(true)
+            // add arguments only if --libafl or --libafl-no-link are present
+            .need_libafl_arg(true)
             .from_args(&args)
             .expect("Failed to parse the command line")
             .link_staticlib(&dir, "fuzzbench")

libafl_cc/src/clang.rs

@@ -60,6 +60,8 @@ pub struct ClangWrapper {
     linking: bool,
     x_set: bool,
     bit_mode: u32,
+    need_libafl_arg: bool,
+    has_libafl_arg: bool,
 
     from_args_called: bool,
     base_args: Vec<String>,
@@ -112,6 +114,11 @@ impl CompilerWrapper for ClangWrapper {
             match arg.as_ref() {
                 "--libafl-no-link" => {
                     linking = false;
+                    self.has_libafl_arg = true;
+                    continue;
+                }
+                "--libafl" => {
+                    self.has_libafl_arg = true;
                     continue;
                 }
                 "-x" => self.x_set = true,
@@ -207,6 +214,10 @@ impl CompilerWrapper for ClangWrapper {
             args.push(self.wrapped_cc.clone());
         }
         args.extend_from_slice(self.base_args.as_slice());
+        if self.need_libafl_arg && !self.has_libafl_arg {
+            return Ok(args);
+        }
+
         if !self.passes.is_empty() {
             args.push("-fno-experimental-new-pass-manager".into());
         }
@@ -270,6 +281,8 @@ impl ClangWrapper {
             linking: false,
             x_set: false,
             bit_mode: 0,
+            need_libafl_arg: false,
+            has_libafl_arg: false,
             from_args_called: false,
             base_args: vec![],
             cc_args: vec![],
@@ -308,6 +321,18 @@ impl ClangWrapper {
         self.passes.push(pass);
         self
     }
+
+    /// Set if linking
+    pub fn linking(&mut self, value: bool) -> &'_ mut Self {
+        self.linking = value;
+        self
+    }
+
+    /// Set if it needs the --libafl arg to add the custom arguments to clang
+    pub fn need_libafl_arg(&mut self, value: bool) -> &'_ mut Self {
+        self.need_libafl_arg = value;
+        self
+    }
 }
 
 #[cfg(test)]