csource: emit bitmasks only when required

2 files changed, 26 insertions, 30 deletions

diff --git a/csource/common.go b/csource/common.go
index c0abd4412..3ac10334d 100644
--- a/csource/common.go
+++ b/csource/common.go
@@ -116,6 +116,22 @@ void debug(const char* msg, ...)
 	fflush(stdout);
 }
 
+#if defined(SYZ_EXECUTOR) || defined(SYZ_USE_BITMASKS)
+#define BITMASK_LEN(type, bf_len) (type)((1ull << (bf_len)) - 1)
+
+#define BITMASK_LEN_OFF(type, bf_off, bf_len) (type)(BITMASK_LEN(type, (bf_len)) << (bf_off))
+
+#define STORE_BY_BITMASK(type, addr, val, bf_off, bf_len)                         \
+	if ((bf_off) == 0 && (bf_len) == 0) {                                     \
+		*(type*)(addr) = (type)(val);                                     \
+	} else {                                                                  \
+		type new_val = *(type*)(addr);                                    \
+		new_val &= ~BITMASK_LEN_OFF(type, (bf_off), (bf_len));            \
+		new_val |= ((type)(val)&BITMASK_LEN(type, (bf_len))) << (bf_off); \
+		*(type*)(addr) = new_val;                                         \
+	}
+#endif
+
 #if defined(SYZ_EXECUTOR) || defined(SYZ_HANDLE_SEGV)
 __thread int skip_segv;
 __thread jmp_buf segv_env;
@@ -175,20 +191,6 @@ static void use_temporary_dir()
 }
 #endif
 
-#define BITMASK_LEN(type, bf_len) (type)((1ull << (bf_len)) - 1)
-
-#define BITMASK_LEN_OFF(type, bf_off, bf_len) (type)(BITMASK_LEN(type, (bf_len)) << (bf_off))
-
-#define STORE_BY_BITMASK(type, addr, val, bf_off, bf_len)                         \
-	if ((bf_off) == 0 && (bf_len) == 0) {                                     \
-		*(type*)(addr) = (type)(val);                                     \
-	} else {                                                                  \
-		type new_val = *(type*)(addr);                                    \
-		new_val &= ~BITMASK_LEN_OFF(type, (bf_off), (bf_len));            \
-		new_val |= ((type)(val)&BITMASK_LEN(type, (bf_len))) << (bf_off); \
-		*(type*)(addr) = new_val;                                         \
-	}
-
 #if defined(SYZ_EXECUTOR) || defined(SYZ_TUN_ENABLE)
 static void vsnprintf_check(char* str, size_t size, const char* format, va_list args)
 {
@@ -551,7 +553,10 @@ static uintptr_t syz_fuseblk_mount(uintptr_t a0, uintptr_t a1, uintptr_t a2, uin
 
 
 #ifndef NONFAILING
-#define NONFAILING(x) { x; }
+#define NONFAILING(x) \
+	{             \
+		x;    \
+	}
 #endif
 
 const char kvm_asm16_cpl3[] = "\x0f\x20\xc0\x66\x83\xc8\x01\x0f\x22\xc0\xb8\xa0\x00\x0f\x00\xd8\xb8\x2b\x00\x8e\xd8\x8e\xc0\x8e\xe0\x8e\xe8\xbc\x00\x01\xc7\x06\x00\x01\x1d\xba\xc7\x06\x02\x01\x23\x00\xc7\x06\x04\x01\x00\x01\xc7\x06\x06\x01\x2b\x00\xcb";
diff --git a/csource/csource.go b/csource/csource.go
index 0a5bcddd7..8faae8e5e 100644
--- a/csource/csource.go
+++ b/csource/csource.go
@@ -42,18 +42,6 @@ type Options struct {
 	Repro bool
 }
 
-func RequiresTun(p *prog.Prog) bool {
-	for _, c := range p.Calls {
-		switch c.Meta.CallName {
-		case "syz_emit_ethernet":
-			return true
-		case "syz_extract_tcp_seq":
-			return true
-		}
-	}
-	return false
-}
-
 func Write(p *prog.Prog, opts Options) ([]byte, error) {
 	exec := make([]byte, prog.ExecBufferSize)
 	if err := p.SerializeForExec(exec, 0); err != nil {
@@ -61,7 +49,7 @@ func Write(p *prog.Prog, opts Options) ([]byte, error) {
 	}
 	w := new(bytes.Buffer)
 
-	if RequiresTun(p) {
+	if prog.RequiresTun(p) {
 		opts.EnableTun = true
 	}
 
@@ -78,7 +66,7 @@ func Write(p *prog.Prog, opts Options) ([]byte, error) {
 	}
 	fmt.Fprintf(w, "\n")
 
-	hdr, err := preprocessCommonHeader(opts, handled)
+	hdr, err := preprocessCommonHeader(opts, handled, prog.RequiresBitmasks(p))
 	if err != nil {
 		return nil, err
 	}
@@ -340,8 +328,11 @@ loop:
 	return calls, n
 }
 
-func preprocessCommonHeader(opts Options, handled map[string]int) (string, error) {
+func preprocessCommonHeader(opts Options, handled map[string]int, useBitmasks bool) (string, error) {
 	var defines []string
+	if useBitmasks {
+		defines = append(defines, "SYZ_USE_BITMASKS")
+	}
 	switch opts.Sandbox {
 	case "none":
 		defines = append(defines, "SYZ_SANDBOX_NONE")