[mc] Comment the binary search in ObjectInformation::find_function()

diff --git a/src/mc/mc_object_info.cpp b/src/mc/mc_object_info.cpp
index 46c4630..e4bdb0d 100644 (file)
--- a/src/mc/mc_object_info.cpp
+++ b/src/mc/mc_object_info.cpp
@@ -128,10 +128,18 @@ simgrid::mc::Frame* ObjectInformation::find_function(const void *ip) const
   int j = this->functions_index.size() - 1;
   while (j >= i) {
     int k = i + ((j - i) / 2);
   int j = this->functions_index.size() - 1;
   while (j >= i) {
     int k = i + ((j - i) / 2);

+
+    /* In most of the search, we do not dereference the base[k].function.
+     * This way the memory accesses are located in the base[k] array. */

     if (ip < base[k].low_pc)
       j = k - 1;
     else if (k < j && ip >= base[k + 1].low_pc)
       i = k + 1;
     if (ip < base[k].low_pc)
       j = k - 1;
     else if (k < j && ip >= base[k + 1].low_pc)
       i = k + 1;

+
+    /* At this point, the search is over.
+     * Either we have found the correct function or we do not know
+     * any function corresponding to this instruction address.
+     * Only at the point do we derefernce the function pointer. */

     else if (ip < base[k].function->high_pc)
       return base[k].function;
     else
     else if (ip < base[k].function->high_pc)
       return base[k].function;
     else