The Tor Browser: tools/trace-malloc/leaksoup.cpp@b8a032363ba2 (annotated)

tools/trace-malloc/leaksoup.cpp@b8a032363ba2 (annotated)

tools/trace-malloc/leaksoup.cpp

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #include "adreader.h"
 #include <stdio.h>
 #include "plhash.h"
 #include "nsTArray.h"
 #include "nsQuickSort.h"
 #include "nsXPCOM.h"
 const uint32_t kPointersDefaultSize = 8;
 /*
  * Read in an allocation dump, presumably one taken at shutdown (using
  * the --shutdown-leaks=file option, which must be used along with
  * --trace-malloc=tmlog), and treat the memory in the dump as leaks.
  * Find the leak roots, including cycles that are roots, by finding the
  * strongly connected components in the graph.  Print output to stdout
  * as HTML.
  */
 struct AllocationNode {
     const ADLog::Entry *entry;
     // Other |AllocationNode| objects whose memory has a pointer to
     // this object.
     nsAutoTArray<AllocationNode*, kPointersDefaultSize> pointers_to;
     // The reverse.
     nsAutoTArray<AllocationNode*, kPointersDefaultSize> pointers_from;
     // Early on in the algorithm, the pre-order index from a DFS.
     // Later on, set to the index of the strongly connected component to
     // which this node belongs.
     uint32_t index;
     bool reached;
     bool is_root;
 };
 static PLHashNumber hash_pointer(const void *key)
 {
     return (PLHashNumber) NS_PTR_TO_INT32(key);
 }
 static int sort_by_index(const void* e1, const void* e2, void*)
 {
     const AllocationNode *n1 = *static_cast<const AllocationNode*const*>(e1);
     const AllocationNode *n2 = *static_cast<const AllocationNode*const*>(e2);
     return n1->index - n2->index;
 }
 static int sort_by_reverse_index(const void* e1, const void* e2, void*)
 {
     const AllocationNode *n1 = *static_cast<const AllocationNode*const*>(e1);
     const AllocationNode *n2 = *static_cast<const AllocationNode*const*>(e2);
     return n2->index - n1->index;
 }
 static void print_escaped(FILE *aStream, const char* aData)
 {
     char c;
     char buf[1000];
     char *p = buf;
     while ((c = *aData++)) {
         switch (c) {
 #define CH(char) *p++ = char
             case '<':
                 CH('&'); CH('l'); CH('t'); CH(';');
                 break;
             case '>':
                 CH('&'); CH('g'); CH('t'); CH(';');
                 break;
             case '&':
                 CH('&'); CH('a'); CH('m'); CH('p'); CH(';');
                 break;
             default:
                 CH(c);
                 break;
 #undef CH
         }
         if (p + 10 > buf + sizeof(buf)) {
             *p = '\0';
             fputs(buf, aStream);
             p = buf;
         }
     }
     *p = '\0';
     fputs(buf, aStream);
 }
 static const char *allocation_format =
   (sizeof(ADLog::Pointer) == 4) ? "0x%08zX" :
   (sizeof(ADLog::Pointer) == 8) ? "0x%016zX" :
   "UNEXPECTED sizeof(void*)";
 int main(int argc, char **argv)
 {
     if (argc != 2) {
         fprintf(stderr,
                 "Expected usage:  %s <sd-leak-file>\n"
                 "  sd-leak-file: Output of --shutdown-leaks=<file> option.\n",
                 argv[0]);
         return 1;
     }
     NS_InitXPCOM2(nullptr, nullptr, nullptr);
     ADLog log;
     if (!log.Read(argv[1])) {
         fprintf(stderr,
                 "%s: Error reading input file %s.\n", argv[0], argv[1]);
     }
     const size_t count = log.count();
     PLHashTable *memory_map =
         PL_NewHashTable(count * 8, hash_pointer, PL_CompareValues,
                         PL_CompareValues, 0, 0);
     if (!memory_map) {
         fprintf(stderr, "%s: Out of memory.\n", argv[0]);
         return 1;
     }
     // Create one |AllocationNode| object for each log entry, and create
     // entries in the hashtable pointing to it for each byte it occupies.
     AllocationNode *nodes = new AllocationNode[count];
     if (!nodes) {
         fprintf(stderr, "%s: Out of memory.\n", argv[0]);
         return 1;
     }
     {
         AllocationNode *cur_node = nodes;
         for (ADLog::const_iterator entry = log.begin(), entry_end = log.end();
              entry != entry_end; ++entry, ++cur_node) {
             const ADLog::Entry *e = cur_node->entry = *entry;
             cur_node->reached = false;
             for (ADLog::Pointer p = e->address,
                             p_end = e->address + e->datasize;
                  p != p_end; ++p) {
                 PLHashEntry *he = PL_HashTableAdd(memory_map, p, cur_node);
                 if (!he) {
                     fprintf(stderr, "%s: Out of memory.\n", argv[0]);
                     return 1;
                 }
             }
         }
     }
     // Construct graph based on pointers.
     for (AllocationNode *node = nodes, *node_end = nodes + count;
          node != node_end; ++node) {
         const ADLog::Entry *e = node->entry;
         for (const char *d = e->data, *d_end = e->data + e->datasize -
                                          e->datasize % sizeof(ADLog::Pointer);
              d != d_end; d += sizeof(ADLog::Pointer)) {
             AllocationNode *target = (AllocationNode*)
                 PL_HashTableLookup(memory_map, *(void**)d);
             if (target) {
                 target->pointers_from.AppendElement(node);
                 node->pointers_to.AppendElement(target);
             }
         }
     }
     // Do a depth-first search on the graph (i.e., by following
     // |pointers_to|) and assign the post-order index to |index|.
     {
         uint32_t dfs_index = 0;
         nsTArray<AllocationNode*> stack;
         for (AllocationNode *n = nodes, *n_end = nodes+count; n != n_end; ++n) {
             if (n->reached) {
                 continue;
             }
             stack.AppendElement(n);
             do {
                 uint32_t pos = stack.Length() - 1;
                 AllocationNode *n = stack[pos];
                 if (n->reached) {
                     n->index = dfs_index++;
                     stack.RemoveElementAt(pos);
                 } else {
                     n->reached = true;
                     // When doing post-order processing, we have to be
                     // careful not to put reached nodes into the stack.
                     for (int32_t i = n->pointers_to.Length() - 1; i >= 0; --i) {
                         AllocationNode* e = n->pointers_to[i];
                         if (!e->reached) {
                             stack.AppendElement(e);
                         }
                     }
                 }
             } while (stack.Length() > 0);
         }
     }
     // Sort the nodes by their DFS index, in reverse, so that the first
     // node is guaranteed to be in a root SCC.
     AllocationNode **sorted_nodes = new AllocationNode*[count];
     if (!sorted_nodes) {
         fprintf(stderr, "%s: Out of memory.\n", argv[0]);
         return 1;
     }
     {
         for (size_t i = 0; i < count; ++i) {
             sorted_nodes[i] = nodes + i;
         }
         NS_QuickSort(sorted_nodes, count, sizeof(AllocationNode*),
                      sort_by_reverse_index, 0);
     }
     // Put the nodes into their strongly-connected components.
     uint32_t num_sccs = 0;
     {
         for (size_t i = 0; i < count; ++i) {
             nodes[i].reached = false;
         }
         nsTArray<AllocationNode*> stack;
         for (AllocationNode **sn = sorted_nodes,
                         **sn_end = sorted_nodes + count; sn != sn_end; ++sn) {
             if ((*sn)->reached) {
                 continue;
             }
             // We found a new strongly connected index.
             stack.AppendElement(*sn);
             do {
                 uint32_t pos = stack.Length() - 1;
                 AllocationNode *n = stack[pos];
                 stack.RemoveElementAt(pos);
                 if (!n->reached) {
                     n->reached = true;
                     n->index = num_sccs;
                     stack.AppendElements(n->pointers_from);
                 }
             } while (stack.Length() > 0);
             ++num_sccs;
         }
     }
     // Identify which nodes are leak roots by using DFS, and watching
     // for component transitions.
     uint32_t num_root_nodes = count;
     {
         for (size_t i = 0; i < count; ++i) {
             nodes[i].is_root = true;
         }
         nsTArray<AllocationNode*> stack;
         for (AllocationNode *n = nodes, *n_end = nodes+count; n != n_end; ++n) {
             if (!n->is_root) {
                 continue;
             }
             // Loop through pointers_to, and add any that are in a
             // different SCC to stack:
             for (int i = n->pointers_to.Length() - 1; i >= 0; --i) {
                 AllocationNode *target = n->pointers_to[i];
                 if (n->index != target->index) {
                     stack.AppendElement(target);
                 }
             }
             while (stack.Length() > 0) {
                 uint32_t pos = stack.Length() - 1;
                 AllocationNode *n = stack[pos];
                 stack.RemoveElementAt(pos);
                 if (n->is_root) {
                     n->is_root = false;
                     --num_root_nodes;
                     stack.AppendElements(n->pointers_to);
                 }
             }
         }
     }
     // Sort the nodes by their SCC index.
     NS_QuickSort(sorted_nodes, count, sizeof(AllocationNode*),
                  sort_by_index, 0);
     // Print output.
     {
         printf("<!DOCTYPE html PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n"
                "<html>\n"
                "<head>\n"
                "<title>Leak analysis</title>\n"
                "<style type=\"text/css\">\n"
                "  .root { background: white; color: black; }\n"
                "  .nonroot { background: #ccc; color: black; }\n"
                "</style>\n"
                "</head>\n");
         printf("<body>\n\n"
                "<p>Generated %zd entries (%d in root SCCs) and %d SCCs.</p>\n\n",
                count, num_root_nodes, num_sccs);
         for (size_t i = 0; i < count; ++i) {
             nodes[i].reached = false;
         }
         // Loop over the sorted nodes twice, first printing the roots
         // and then the non-roots.
         for (int32_t root_type = true;
              root_type == true || root_type == false; --root_type) {
             if (root_type) {
                 printf("\n\n"
                        "<div class=\"root\">\n"
                        "<h1 id=\"root\">Root components</h1>\n");
             } else {
                 printf("\n\n"
                        "<div class=\"nonroot\">\n"
                        "<h1 id=\"nonroot\">Non-root components</h1>\n");
             }
             uint32_t component = (uint32_t)-1;
             bool one_object_component;
             for (const AllocationNode *const* sn = sorted_nodes,
                                   *const* sn_end = sorted_nodes + count;
                  sn != sn_end; ++sn) {
                 const AllocationNode *n = *sn;
                 if (n->is_root != root_type)
                     continue;
                 const ADLog::Entry *e = n->entry;
                 if (n->index != component) {
                     component = n->index;
                     one_object_component =
                         sn + 1 == sn_end || (*(sn+1))->index != component;
                     if (!one_object_component)
                         printf("\n\n<h2 id=\"c%d\">Component %d</h2>\n",
                                component, component);
                 }
                 if (one_object_component) {
                     printf("\n\n<div id=\"c%d\">\n", component);
                     printf("<h2 id=\"o%td\">Object %td "
                            "(single-object component %d)</h2>\n",
                            n-nodes, n-nodes, component);
                 } else {
                     printf("\n\n<h3 id=\"o%td\">Object %td</h3>\n",
                            n-nodes, n-nodes);
                 }
                 printf("<pre>\n");
                 printf("%p &lt;%s&gt; (%zd)\n",
                        e->address, e->type, e->datasize);
                 for (size_t d = 0; d < e->datasize;
                      d += sizeof(ADLog::Pointer)) {
                     AllocationNode *target = (AllocationNode*)
                         PL_HashTableLookup(memory_map, *(void**)(e->data + d));
                     if (target) {
                         printf("        <a href=\"#o%td\">",
                                target - nodes);
                         printf(allocation_format,
                                *(size_t*)(e->data + d));
                         printf("</a> &lt;%s&gt;",
                                target->entry->type);
                         if (target->index != n->index) {
                             printf(", component %d", target->index);
                         }
                         printf("\n");
                     } else {
                         printf("        ");
                         printf(allocation_format,
                                *(size_t*)(e->data + d));
                         printf("\n");
                     }
                 }
                 if (n->pointers_from.Length()) {
                     printf("\nPointers from:\n");
                     for (uint32_t i = 0, i_end = n->pointers_from.Length();
                          i != i_end; ++i) {
                         AllocationNode *t = n->pointers_from[i];
                         const ADLog::Entry *te = t->entry;
                         printf("    <a href=\"#o%td\">%s</a> (Object %td, ",
                                t - nodes, te->type, t - nodes);
                         if (t->index != n->index) {
                             printf("component %d, ", t->index);
                         }
                         if (t == n) {
                             printf("self)\n");
                         } else {
                             printf("%p)\n", te->address);
                         }
                     }
                 }
                 print_escaped(stdout, e->allocation_stack);
                 printf("</pre>\n");
                 if (one_object_component) {
                     printf("</div>\n");
                 }
             }
             printf("</div>\n");
         }
         printf("</body>\n"
                "</html>\n");
     }
     delete [] sorted_nodes;
     delete [] nodes;
     NS_ShutdownXPCOM(nullptr);
     return 0;
 }

The Tor Browser / annotate

tools/trace-malloc/leaksoup.cpp@b8a032363ba2 (annotated)

tools/trace-malloc/leaksoup.cpp