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[mc] Compute a single hash (64 bits) of the current state
[simgrid.git] / src / mc / mc_hash.c
diff --git a/src/mc/mc_hash.c b/src/mc/mc_hash.c
new file mode 100644 (file)
index 0000000..86847a9
--- /dev/null
@@ -0,0 +1,376 @@
+/* Copyright (c) 2014. The SimGrid Team.
+ * All rights reserved.                                                     */
+
+/* This program is free software; you can redistribute it and/or modify it
+ * under the terms of the license (GNU LGPL) which comes with this package. */
+
+#include <stdint.h>
+#include <stdbool.h>
+
+#include "mc_private.h"
+#include "mc/datatypes.h"
+#include <mc/mc.h>
+
+XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_hash, mc,
+                                "Logging specific to mc_hash");
+
+// This is djb2:
+typedef uint64_t mc_hash_t;
+#define MC_HASH_INIT ((uint64_t)5381)
+
+// #define MC_HASH(hash, value) hash = (((hash << 5) + hash) + (uint64_t) value)
+#define MC_HASH(hash, value) \
+  { hash = (((hash << 5) + hash) + (uint64_t) value);\
+  XBT_DEBUG("%s:%i: %"PRIx64" -> %"PRIx64, __FILE__, __LINE__, (uint64_t) value, hash); }
+
+// ***** Hash state
+
+typedef struct s_mc_hashing_state {
+  // Set of pointers/addresses already processed (avoid loops):
+  mc_address_set_t handled_addresses;
+} mc_hashing_state;
+
+void mc_hash_state_init(mc_hashing_state* state);
+void mc_hash_state_destroy(mc_hashing_state* state);
+
+void mc_hash_state_init(mc_hashing_state* state) {
+  state->handled_addresses = mc_address_set_new();
+}
+
+void mc_hash_state_destroy(mc_hashing_state* state) {
+   mc_address_set_free(&state->handled_addresses);
+}
+
+// TODO, detect and avoid loops
+
+static bool mc_ignored(const void* address, size_t size) {
+  mc_heap_ignore_region_t region;
+  unsigned int cursor = 0;
+  const void* end = (char*) address + size;
+  xbt_dynar_foreach(mc_heap_comparison_ignore, cursor, region) {
+   void* istart = region->address;
+   void* iend   = (char*) region->address + region->size;
+
+   if(address>=istart && address<iend && end>=istart && end<iend)
+     return true;
+  }
+
+  return false;
+}
+
+static void mc_hash_binary(mc_hash_t *hash, const void* s, size_t len) {
+  const char* p = (const void*) s;
+  int i;
+  for(i=0; i!=len; ++i) {
+    MC_HASH(*hash, p[i]);
+  }
+}
+
+/** \brief Compute a hash for a given value of a given type
+ *
+ *  We try to be very conservative (do not hash too ambiguous things).
+ *
+ *  \param address address of the variable
+ *  \param type type of the variable
+ * */
+static void mc_hash_value(mc_hash_t* hash, mc_hashing_state* state, mc_object_info_t info, const void* address, dw_type_t type) {
+  top:
+
+  switch(type->type){
+  // Simple case, hash this has binary:
+  case DW_TAG_base_type:
+  case DW_TAG_enumeration_type:
+  {
+    if(mc_ignored(address, 1))
+      return;
+    mc_hash_binary(hash, address, type->byte_size);
+    return;
+  }
+
+  case DW_TAG_array_type:
+  {
+    if(mc_ignored(address, type->byte_size))
+      return;
+
+    long element_count = type->element_count;
+    dw_type_t subtype = xbt_dict_get_or_null(info->types, type->dw_type_id);
+    if(subtype==NULL) {
+      XBT_DEBUG("Hash array without subtype");
+      return;
+    }
+    int i;
+    for(i=0; i!=element_count; ++i) {
+      XBT_DEBUG("Hash array element %i", i);
+      void* subaddress = ((char*)address)+i*subtype->byte_size;
+      mc_hash_value(hash, state, info, subaddress, subtype);
+    }
+    return;
+  }
+
+  // Get the raw type:
+  case DW_TAG_typedef:
+  case DW_TAG_volatile_type:
+  case DW_TAG_const_type:
+  case DW_TAG_restrict_type:
+  {
+    if(type->dw_type_id==NULL) {
+      return;
+    }
+    type = xbt_dict_get_or_null(info->types, type->dw_type_id);
+    if(type==NULL)
+      return;
+    else
+      goto top;
+  }
+
+  case DW_TAG_structure_type:
+  case DW_TAG_class_type:
+  {
+    if(mc_ignored(address, type->byte_size))
+      return;
+
+    unsigned int cursor = 0;
+    dw_type_t member;
+    xbt_dynar_foreach(type->members, cursor, member){
+      XBT_DEBUG("Hash struct member %s", member->name);
+      dw_type_t subtype = xbt_dict_get_or_null(info->types, member->dw_type_id);
+      if(subtype==NULL)
+        return;
+       mc_hash_value(hash, state, info, ((char*)address) + member->offset, subtype);
+    }
+    return;
+  }
+
+  // Pointer, we hash a single value but it might be an array.
+  case DW_TAG_pointer_type:
+  case DW_TAG_reference_type:
+  case DW_TAG_rvalue_reference_type:
+  {
+    if(mc_ignored(address, 1))
+      return;
+
+    void* pointed = *(void**)address;
+    if(pointed==NULL) {
+      XBT_DEBUG("Hashed pinter is NULL");
+      return;
+    }
+
+    // Avoid loops:
+    if(mc_address_test(state->handled_addresses, pointed)) {
+      XBT_DEBUG("Hashed pointed data %p already hashed", pointed);
+      return;
+    }
+    mc_address_add(state->handled_addresses, pointed);
+
+    // Anything outside the R/W segments and the heap is not hashed:
+    bool valid_pointer = (pointed >= (void*) mc_binary_info->start_rw && pointed <= (void*) mc_binary_info->end_rw)
+        || (pointed >= (void*) mc_libsimgrid_info->start_rw && pointed <= (void*) mc_libsimgrid_info->end_rw)
+        || (pointed >= std_heap && pointed < (void*) ((const char*)std_heap + STD_HEAP_SIZE));
+    if(!valid_pointer) {
+      XBT_DEBUG("Hashed pointed data %p is in an ignored range", pointed);
+      return;
+    }
+
+    dw_type_t subtype = type->dw_type_id == NULL ? NULL : xbt_dict_get_or_null(info->types, type->dw_type_id);
+    if(subtype==NULL) {
+      XBT_DEBUG("Missing type for %p (type=%s)", pointed, type->dw_type_id);
+      return;
+    }
+
+    address = pointed;
+    type = subtype;
+    goto top;
+  }
+
+  // Skip this:
+  case DW_TAG_union_type:
+  case DW_TAG_subroutine_type:
+  default:
+    return;
+  }
+}
+
+
+static void mc_hash_object_globals(mc_hash_t *hash, mc_hashing_state* state, mc_object_info_t info) {
+  unsigned int cursor = 0;
+  dw_variable_t variable;
+  xbt_dynar_foreach(info->global_variables, cursor, variable) {
+    XBT_DEBUG("Hash global variable %s", variable->name);
+
+    if(variable->type_origin == NULL) {
+      // Nothing
+      continue;
+    }
+
+    dw_type_t type = xbt_dict_get_or_null(info->types, variable->type_origin);
+    if(type==NULL) {
+      // Nothing
+      continue;
+    }
+
+    const char* address = variable->address.address;
+    bool valid_pointer = (address >= mc_binary_info->start_rw && address <= mc_binary_info->end_rw)
+        || (address >= mc_libsimgrid_info->start_rw && address <= mc_libsimgrid_info->end_rw)
+        || (address >= (const char*) std_heap && address < (const char *)std_heap + STD_HEAP_SIZE);
+    if(!valid_pointer) continue;
+
+    mc_hash_value(hash, state, info, variable->address.address, type);
+  }
+}
+
+static void mc_hash_stack_frame(
+  mc_hash_t *hash,
+    mc_object_info_t info, unw_cursor_t* unw_cursor, dw_frame_t frame, char* frame_pointer, mc_hashing_state* state
+    ) {
+
+  // return; // TEMP
+
+  unsigned int cursor = 0;
+  dw_variable_t variable;
+  xbt_dynar_foreach(frame->variables, cursor, variable){
+
+    if(variable->type_origin==NULL) {
+      XBT_DEBUG("Hash local variable %s without type", variable->name);
+      continue;
+    }
+    if(variable->address.location == NULL) {
+      XBT_DEBUG("Hash local variable %s without location", variable->name);
+      continue;
+    }
+
+    XBT_DEBUG("Hash local variable %s", variable->name);
+
+    void* variable_address = (void*) MC_dwarf_resolve_location(unw_cursor, variable->address.location, frame_pointer);
+
+    dw_type_t type = xbt_dict_get_or_null(info->types, variable->type_origin);
+    if(type==NULL) {
+      XBT_DEBUG("Hash local variable %s without loctypeation", variable->name);
+      continue;
+    }
+
+    mc_hash_value(hash, state, info, variable_address, type);
+  }
+}
+
+/** \brief Find the frame base of a given frame
+ *
+ *  \param ip         Instruction pointer
+ *  \param frame
+ *  \param unw_cursor
+ */
+void* mc_find_frame_base(unw_word_t ip, dw_frame_t frame, unw_cursor_t* unw_cursor) {
+  switch(frame->frame_base->type) {
+  case e_dw_loclist:
+  {
+    int loclist_cursor;
+    for(loclist_cursor=0; loclist_cursor < xbt_dynar_length(frame->frame_base->location.loclist); loclist_cursor++){
+      dw_location_entry_t entry = xbt_dynar_get_as(frame->frame_base->location.loclist, loclist_cursor, dw_location_entry_t);
+      if((ip >= entry->lowpc) && (ip < entry->highpc)){
+        return (void*) MC_dwarf_resolve_location(unw_cursor, entry->location, NULL);
+      }
+    }
+    return NULL;
+  }
+  // Not handled:
+  default:
+    return NULL;
+  }
+}
+
+static void mc_hash_stack(mc_hash_t *hash, stack_region_t stack, mc_hashing_state* state) {
+
+  unw_cursor_t cursor;
+  if(unw_init_local(&cursor, (unw_context_t *)stack->context)){
+    xbt_die("unw_init_local failed");
+  }
+
+  MC_HASH(*hash, (long)stack->address);
+
+  long count = 0;
+
+  int ret;
+  for(ret=1; ret >= 0; ret = unw_step(&cursor)) {
+
+    // Find the frame name:
+    unw_word_t off;
+    char frame_name[256];
+    if(unw_get_proc_name(&cursor, frame_name, sizeof (frame_name), &off)!=0) {
+      continue;
+    }
+
+    XBT_DEBUG("Frame #%i %s", (int) count, frame_name);
+
+    // Stop before context switch with maestro
+    if(!strcmp(frame_name, "smx_ctx_sysv_wrapper")) {
+      break;
+    }
+
+    ++count;
+
+    unw_word_t ip, sp;
+    if(unw_get_reg(&cursor, UNW_REG_IP, &ip))
+      continue;
+    if(unw_get_reg(&cursor, UNW_REG_SP, &sp))
+      continue;
+
+    MC_HASH(*hash, ip);
+
+    // Find the object info:
+    mc_object_info_t info;
+    if((long)ip >= (long) mc_libsimgrid_info->start_exec && (long)ip < (long) mc_libsimgrid_info->end_exec)
+      info = mc_libsimgrid_info;
+    else if((long)ip >= (long) mc_binary_info->start_exec && (long)ip < (long) mc_binary_info->end_exec)
+      info = mc_binary_info;
+    else
+      continue;
+
+    // Find the frame:
+    dw_frame_t frame = xbt_dict_get_or_null(info->local_variables, frame_name);
+    if(frame==NULL)
+      continue;
+
+    long true_ip = (long)frame->low_pc + (long)off;
+
+    // Find the fame base:
+    void* frame_base = mc_find_frame_base(true_ip, frame, &cursor);
+    if(frame_base==NULL)
+      continue;
+
+    mc_hash_stack_frame(hash, info, &cursor, frame, frame_base, state);
+  }
+
+  MC_HASH(*hash, count);
+}
+
+static void mc_hash_stacks(mc_hash_t *hash, mc_hashing_state* state) {
+  unsigned int cursor = 0;
+  stack_region_t current_stack;
+
+  MC_HASH(*hash, xbt_dynar_length(stacks_areas));
+
+  int i=0;
+  xbt_dynar_foreach(stacks_areas, cursor, current_stack){
+    XBT_DEBUG("Stack %i", i);
+    mc_hash_stack(hash, current_stack, state);
+    ++i;
+  }
+}
+
+uint64_t mc_hash_processes_state(int num_state) {
+  XBT_DEBUG("START hash %i", num_state);
+
+  mc_hashing_state state;
+  mc_hash_state_init(&state);
+
+  mc_hash_t hash = MC_HASH_INIT;
+
+  MC_HASH(hash, xbt_swag_size(simix_global->process_list)); // process count
+  mc_hash_object_globals(&hash, &state, mc_binary_info);
+  // mc_hash_object_globals(&hash, &state, mc_libsimgrid_info);
+  mc_hash_stacks(&hash, &state);
+
+  mc_hash_state_destroy(&state);
+
+  XBT_DEBUG("END hash %i", num_state);
+  return hash;
+}