this->byte_size = 0;
this->element_count = 0;
this->is_pointer_type = 0;
+ this->type_id = 0;
this->subtype = nullptr;
this->full_type = nullptr;
}
this->dwarf_offset = 0;
this->global = 0;
this->type = nullptr;
+ this->type_id = 0;
this->address = nullptr;
this->start_scope = 0;
this->object_info = nullptr;
ObjectInformation::ObjectInformation()
{
this->flags = 0;
- this->file_name = nullptr;
this->start = nullptr;
this->end = nullptr;
this->start_exec = nullptr;
this->end_rw = nullptr;
this->start_ro = nullptr;
this->end_ro = nullptr;
- this->subprograms = xbt_dict_new_homogeneous(mc_frame_free);
- this->types = xbt_dict_new_homogeneous((void (*)(void *)) mc_type_free);
- this->full_types_by_name = xbt_dict_new_homogeneous(NULL);
- this->functions_index = nullptr;
-}
-
-ObjectInformation::~ObjectInformation()
-{
- xbt_free(this->file_name);
- xbt_dict_free(&this->subprograms);
- xbt_dict_free(&this->types);
- xbt_dict_free(&this->full_types_by_name);
- xbt_dynar_free(&this->functions_index);
}
/** Find the DWARF offset for this ELF object
*
* An offset is applied to address found in DWARF:
*
- * <ul>
- * <li>for an executable obejct, addresses are virtual address
- * (there is no offset) i.e. \f$\text{virtual address} = \{dwarf address}\f$;</li>
- * <li>for a shared object, the addreses are offset from the begining
- * of the shared object (the base address of the mapped shared
- * object must be used as offset
- * i.e. \f$\text{virtual address} = \text{shared object base address}
- * + \text{dwarf address}\f$.</li>
+ * * for an executable obejct, addresses are virtual address
+ * (there is no offset) i.e.
+ * \f$\text{virtual address} = \{dwarf address}\f$;
*
+ * * for a shared object, the addreses are offset from the begining
+ * of the shared object (the base address of the mapped shared
+ * object must be used as offset
+ * i.e. \f$\text{virtual address} = \text{shared object base address}
+ * + \text{dwarf address}\f$.
*/
void *ObjectInformation::base_address() const
{
return result;
}
-mc_frame_t ObjectInformation::find_function(const void *ip) const
+/* Find a function by instruction pointer */
+simgrid::mc::Frame* ObjectInformation::find_function(const void *ip) const
{
- xbt_dynar_t dynar = this->functions_index;
- mc_function_index_item_t base =
- (mc_function_index_item_t) xbt_dynar_get_ptr(dynar, 0);
+ /* This is implemented by binary search on a sorted array.
+ *
+ * We do quite a lot ot those so we want this to be cache efficient.
+ * We pack the only information we need in the index entries in order
+ * to successfully do the binary search. We do not need the high_pc
+ * during the binary search (only at the end) so it is not included
+ * in the index entry. We could use parallel arrays as well.
+ *
+ * We cannot really use the std:: alogrithm for this.
+ * We could use std::binary_search by including the high_pc inside
+ * the FunctionIndexEntry.
+ */
+ const simgrid::mc::FunctionIndexEntry* base =
+ this->functions_index.data();
int i = 0;
- int j = xbt_dynar_length(dynar) - 1;
+ int j = this->functions_index.size() - 1;
while (j >= i) {
int k = i + ((j - i) / 2);
- if (ip < base[k].low_pc) {
+
+ /* 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 (ip >= base[k].high_pc) {
+ else if (k < j && ip >= base[k + 1].low_pc)
i = k + 1;
- } else {
+
+ /* 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
+ return nullptr;
}
return nullptr;
}
