Add edge profiling support to the runtime library

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@12227 91177308-0d34-0410-b5e6-96231b3b80d8

runtime/libprofile/EdgeProfiling.c

@@ -0,0 +1,45 @@
+/*===-- EdgeProfiling.c - Support library for edge profiling --------------===*\
+|*
+|*                     The LLVM Compiler Infrastructure
+|*
+|* This file was developed by the LLVM research group and is distributed under
+|* the University of Illinois Open Source License. See LICENSE.TXT for details.
+|* 
+|*===----------------------------------------------------------------------===*|
+|* 
+|* This file implements the call back routines for the edge profiling
+|* instrumentation pass.  This should be used with the -insert-edge-profiling
+|* LLVM pass.
+|*
+\*===----------------------------------------------------------------------===*/
+
+#include "Profiling.h"
+#include <stdlib.h>
+
+static unsigned *ArrayStart;
+static unsigned NumElements;
+
+/* EdgeProfAtExitHandler - When the program exits, just write out the profiling
+ * data.
+ */
+static void EdgeProfAtExitHandler() {
+  /* Note that if this were doing something more intellegent with the
+     instrumentation, that we could do some computation here to expand what we
+     collected into simple edge profiles.  Since we directly count each edge, we
+     just write out all of the counters directly.
+  */
+  write_profiling_data(Edge, ArrayStart, NumElements);
+}
+
+
+/* llvm_start_edge_profiling - This is the main entry point of the edge
+ * profiling library.  It is responsible for setting up the atexit handler.
+ */
+int llvm_start_edge_profiling(int argc, const char **argv,
+                              unsigned *arrayStart, unsigned numElements) {
+  int Ret = save_arguments(argc, argv);
+  ArrayStart = arrayStart;
+  NumElements = numElements;
+  atexit(EdgeProfAtExitHandler);
+  return Ret;
+}