libsysprof: add utility to build symbol maps

These are useful to allow us to append symbol informatio to a capture file
using the existing symbol resolvers.

It can read/write a small format embedded within capture files so that
we can append them from the target machine rather than decoding from the
machine we run Sysprof UI on.

src/tests/test-addr-map.c

@@ -0,0 +1,105 @@
+#include <fcntl.h>
+#include <sysprof.h>
+
+#include "sysprof-platform.h"
+#include "sysprof-symbol-map.h"
+
+static GMainLoop *main_loop;
+
+static void *
+resolve_in_thread (gpointer data)
+{
+  SysprofCaptureReader *reader = data;
+  g_autoptr(SysprofSymbolResolver) kernel = NULL;
+  g_autoptr(SysprofSymbolResolver) elf = NULL;
+  SysprofCaptureFrameType type;
+  SysprofSymbolMap *map;
+  gboolean r;
+  int fd;
+
+  g_assert (reader != NULL);
+
+  map = sysprof_symbol_map_new ();
+  kernel = sysprof_kernel_symbol_resolver_new ();
+  elf = sysprof_elf_symbol_resolver_new ();
+
+  sysprof_symbol_map_add_resolver (map, kernel);
+  sysprof_symbol_map_add_resolver (map, elf);
+
+  sysprof_symbol_map_resolve (map, reader);
+
+  fd = sysprof_memfd_create ("decode-test");
+  g_assert_cmpint (fd, !=, -1);
+
+  r = sysprof_symbol_map_serialize (map, fd);
+  g_assert_true (r);
+  sysprof_symbol_map_free (map);
+
+  /* Reset some state */
+  sysprof_capture_reader_reset (reader);
+  lseek (fd, SEEK_SET, 0);
+
+  /* Now desrialize it */
+  map = sysprof_symbol_map_new ();
+  sysprof_symbol_map_deserialize (map, G_BYTE_ORDER, fd);
+
+  /* Now try to print some stack traces */
+  while (sysprof_capture_reader_peek_type (reader, &type))
+    {
+      if (type == SYSPROF_CAPTURE_FRAME_SAMPLE)
+        {
+          const SysprofCaptureSample *sample = NULL;
+
+          if (!(sample = sysprof_capture_reader_read_sample (reader)))
+            break;
+
+          for (guint j = 0; j < sample->n_addrs; j++)
+            {
+              const gchar *name;
+              GQuark tag;
+
+              if (!(name = sysprof_symbol_map_lookup (map, sample->frame.time, sample->frame.pid, sample->addrs[j], &tag)))
+                name = "Unknown symbol";
+
+              g_print ("%u: %s\n", j, name);
+            }
+
+          g_print ("======\n");
+        }
+      else if (!sysprof_capture_reader_skip (reader))
+        break;
+    }
+
+
+  sysprof_symbol_map_free (map);
+
+  close (fd);
+  g_main_loop_quit (main_loop);
+  return NULL;
+}
+
+gint
+main (gint argc,
+      gchar *argv[])
+{
+  g_autoptr(SysprofCaptureReader) reader = NULL;
+  g_autoptr(GError) error = NULL;
+
+  if (argc != 2)
+    {
+      g_printerr ("usage: %s CAPTURE_FILE\n", argv[0]);
+      return 1;
+    }
+
+  if (!(reader = sysprof_capture_reader_new (argv[1], &error)))
+    {
+      g_printerr ("%s\n", error->message);
+      return 1;
+    }
+
+  main_loop = g_main_loop_new (NULL, FALSE);
+  g_thread_new ("reader-thread", resolve_in_thread, reader);
+  g_main_loop_run (main_loop);
+
+  return 0;
+}