[TSan] Remove unused setjmp definitions

[melver]

Summary

The __interceptor_*setjmp() definitions appear to have been defined for
the purpose of TSAN_INTERCEPT(), but on non-Mac systems, it seems
TSAN_INTERCEPT() isn't even being used anymore for setjmp.

Remove them. Nothing should call them anyway (due to CHECK-fail), so
having the linker fail is better than failing at runtime.

compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp

 #if SANITIZER_NETBSD
 #define setjmp_symname __setjmp14
 #define sigsetjmp_symname __sigsetjmp14
 #else
 #define setjmp_symname setjmp
 #define sigsetjmp_symname sigsetjmp
 #endif
 
-#define TSAN_INTERCEPTOR_SETJMP_(x) __interceptor_ ## x
-#define TSAN_INTERCEPTOR_SETJMP__(x) TSAN_INTERCEPTOR_SETJMP_(x)
-#define TSAN_INTERCEPTOR_SETJMP TSAN_INTERCEPTOR_SETJMP__(setjmp_symname)
-#define TSAN_INTERCEPTOR_SIGSETJMP TSAN_INTERCEPTOR_SETJMP__(sigsetjmp_symname)
-
-#define TSAN_STRING_SETJMP SANITIZER_STRINGIFY(setjmp_symname)
-#define TSAN_STRING_SIGSETJMP SANITIZER_STRINGIFY(sigsetjmp_symname)
-
-// Not called.  Merely to satisfy TSAN_INTERCEPT().
-extern "C" SANITIZER_INTERFACE_ATTRIBUTE
-int TSAN_INTERCEPTOR_SETJMP(void *env);
-extern "C" int TSAN_INTERCEPTOR_SETJMP(void *env) {
-  CHECK(0);
-  return 0;
-}
-
-// FIXME: any reason to have a separate declaration?
-extern "C" SANITIZER_INTERFACE_ATTRIBUTE
-int __interceptor__setjmp(void *env);
-extern "C" int __interceptor__setjmp(void *env) {
-  CHECK(0);
-  return 0;
-}
-
-extern "C" SANITIZER_INTERFACE_ATTRIBUTE
-int TSAN_INTERCEPTOR_SIGSETJMP(void *env);
-extern "C" int TSAN_INTERCEPTOR_SIGSETJMP(void *env) {
-  CHECK(0);
-  return 0;
-}
-
-#if !SANITIZER_NETBSD
-extern "C" SANITIZER_INTERFACE_ATTRIBUTE
-int __interceptor___sigsetjmp(void *env);
-extern "C" int __interceptor___sigsetjmp(void *env) {
-  CHECK(0);
-  return 0;
-}
-#endif
-
-extern "C" int setjmp_symname(void *env);
-extern "C" int _setjmp(void *env);
-extern "C" int sigsetjmp_symname(void *env);
-#if !SANITIZER_NETBSD
-extern "C" int __sigsetjmp(void *env);
-#endif
 DEFINE_REAL(int, setjmp_symname, void *env)
 DEFINE_REAL(int, _setjmp, void *env)
 DEFINE_REAL(int, sigsetjmp_symname, void *env)
 #if !SANITIZER_NETBSD
 DEFINE_REAL(int, __sigsetjmp, void *env)
 #endif
+
+// The real interceptor for setjmp is special, and implemented in pure asm. We
+// just need to initialize the REAL functions so that they can be used in asm.
+static void InitializeSetjmpInterceptors() {
+  // We can not use TSAN_INTERCEPT to get setjmp addr, because it does &setjmp and
+  // setjmp is not present in some versions of libc.
+  using __interception::InterceptFunction;
+  InterceptFunction(SANITIZER_STRINGIFY(setjmp_symname), (uptr*)&REAL(setjmp_symname), 0, 0);
+  InterceptFunction("_setjmp", (uptr*)&REAL(_setjmp), 0, 0);
+  InterceptFunction(SANITIZER_STRINGIFY(sigsetjmp_symname), (uptr*)&REAL(sigsetjmp_symname), 0,
+                    0);
+#if !SANITIZER_NETBSD
+  InterceptFunction("__sigsetjmp", (uptr*)&REAL(__sigsetjmp), 0, 0);
+#endif
+}
 #endif  // SANITIZER_APPLE
 
 #if SANITIZER_NETBSD
 #define longjmp_symname __longjmp14
 #define siglongjmp_symname __siglongjmp14
 #else
 #define longjmp_symname longjmp
 #define siglongjmp_symname siglongjmp
#endif
 
   new(interceptor_ctx()) InterceptorContext();
 
   InitializeCommonInterceptors();
   InitializeSignalInterceptors();
   InitializeLibdispatchInterceptors();
 
 #if !SANITIZER_APPLE
-  // We can not use TSAN_INTERCEPT to get setjmp addr,
-  // because it does &setjmp and setjmp is not present in some versions of libc.
-  using __interception::InterceptFunction;
-  InterceptFunction(TSAN_STRING_SETJMP, (uptr*)&REAL(setjmp_symname), 0, 0);
-  InterceptFunction("_setjmp", (uptr*)&REAL(_setjmp), 0, 0);
-  InterceptFunction(TSAN_STRING_SIGSETJMP, (uptr*)&REAL(sigsetjmp_symname), 0,
-                    0);
-#if !SANITIZER_NETBSD
-  InterceptFunction("__sigsetjmp", (uptr*)&REAL(__sigsetjmp), 0, 0);
-#endif
+  InitializeSetjmpInterceptors();
 #endif
 
   TSAN_INTERCEPT(longjmp_symname);
   TSAN_INTERCEPT(siglongjmp_symname);
 #if SANITIZER_NETBSD
   TSAN_INTERCEPT(_longjmp);
 #endif