Address PR274 - '[JIT] Programs cannot resolve the fstat function'

by trying to get the compiler to generate an undefined reference for it
and related functions which live in libc_nonshared.a on Linux.

Linkers... sigh.

llvm-svn: 12256

llvm/lib/ExecutionEngine/JIT/Intercept.cpp

@@ -18,6 +18,7 @@
 #include "JIT.h"
 #include "Support/DynamicLinker.h"
 #include <iostream>
+#include <sys/stat.h>
 using namespace llvm;
 
 // AtExitHandlers - List of functions to call when the program exits,
@@ -40,6 +41,23 @@ static void runAtExitHandlers() {
 // Function stubs that are invoked instead of certain library calls
 //===----------------------------------------------------------------------===//
 
+// Force the following functions to be linked in to anything that uses the
+// JIT. This is a hack designed to work around the all-too-clever Glibc
+// strategy of making these functions work differently when inlined vs. when
+// not inlined, and hiding their real definitions in a separate archive file
+// that the dynamic linker can't see. For more info, search for
+// 'libc_nonshared.a' on Google, or read http://llvm.cs.uiuc.edu/PR274.
+void *FunctionPointers[] = {
+  (void *) stat,
+  (void *) stat64,
+  (void *) fstat,
+  (void *) fstat64,
+  (void *) lstat,
+  (void *) lstat64,
+  (void *) atexit,
+  (void *) mknod
+};
+
 // NoopFn - Used if we have nothing else to call...
 static void NoopFn() {}