Merge pull request #10107 from dra27/afl

Always allow linking AFL-instrumented modules

(cherry picked from commit 15c5679)

Changes

@@ -3,10 +3,15 @@ OCaml 4.12, maintenance version
 
 ### Bug fixes:
 
+- #10107: Ensure modules compiled with -afl-instrument can still link on
+  platforms without AFL support.
+  (David Allsopp, review by Xavier Leroy)
+
 - #10294, #10295: fix an assert-failure in pattern-matching compilation
   (Gabriel Scherer, review by Thomas Refis and Luc Maranget,
    report by Nicolás Ojeda Bär)
 
+
 OCaml 4.12.0 (24 February 2021)
 -------------------------------
 

runtime/afl.c

@@ -15,6 +15,11 @@
 /* Runtime support for afl-fuzz */
 #include "caml/config.h"
 
+/* Values used by the instrumentation logic (see cmmgen.ml) */
+static unsigned char afl_area_initial[1 << 16];
+unsigned char* caml_afl_area_ptr = afl_area_initial;
+uintnat caml_afl_prev_loc;
+
 #if !defined(HAS_SYS_SHM_H) || !defined(HAS_SHMAT)
 
 #include "caml/mlvalues.h"
@@ -29,6 +34,12 @@ CAMLprim value caml_reset_afl_instrumentation(value unused)
   return Val_unit;
 }
 
+CAMLexport value caml_setup_afl(value unit)
+{
+  /* AFL is not supported */
+  return Val_unit;
+}
+
 #else
 
 #include <unistd.h>
@@ -50,11 +61,6 @@ static int afl_initialised = 0;
    to count a testcase as "crashing" */
 extern int caml_abort_on_uncaught_exn;
 
-/* Values used by the instrumentation logic (see cmmgen.ml) */
-static unsigned char afl_area_initial[1 << 16];
-unsigned char* caml_afl_area_ptr = afl_area_initial;
-uintnat caml_afl_prev_loc;
-
 /* File descriptors used to synchronise with afl-fuzz */
 #define FORKSRV_FD_READ 198
 #define FORKSRV_FD_WRITE 199