[Fuchsia] Fix ids.txt data format, enable symbolization of SDK libraries.

The ids.txt file was being created without newlines between entries,
preventing it from being read correctly.

Also enable symbolization for binaries provided in the SDK, now that the
symbolizer supports multiple sources of symbols.


Bug: 772252
Change-Id: I2c0e179d09a26248f5d0c17c61bda7b2ccd05ee6
Reviewed-on: https://chromium-review.googlesource.com/c/1488576Reviewed-by: Wez <wez@chromium.org>
Reviewed-by: Sergey Ulanov <sergeyu@chromium.org>
Commit-Queue: Kevin Marshall <kmarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#635840}

build/config/fuchsia/prepare_package_inputs.py

@@ -96,9 +96,14 @@ def _WriteBuildIdsTxt(binary_paths, ids_txt_path):
         assert binary_shortname in unprocessed_binary_paths
 
       elif line.startswith(READELF_BUILD_ID_PREFIX):
+        # Paths to the unstripped executables listed in "ids.txt" are specified
+        # as relative paths to that file.
+        unstripped_rel_path = os.path.relpath(
+            os.path.abspath(unprocessed_binary_paths[binary_shortname]),
+            os.path.dirname(os.path.abspath(ids_txt_path)))
+
         build_id = line[len(READELF_BUILD_ID_PREFIX):]
-        ids_file.write(build_id + ' ' +
-                       unprocessed_binary_paths[binary_shortname])
+        ids_file.write(build_id + ' ' + unstripped_rel_path + '\n')
         del unprocessed_binary_paths[binary_shortname]
 
   # Did readelf forget anything? Make sure that all binaries are accounted for.

build/fuchsia/symbolizer.py

@@ -22,7 +22,8 @@ def SymbolizerFilter(input_fd, build_ids_file):
                                       'llvm-symbolizer')
   symbolizer = os.path.join(SDK_ROOT, 'tools', 'symbolize')
   symbolizer_cmd = [symbolizer, '-ids', build_ids_file,
-                    '-ids-rel', '-llvm-symbolizer', llvm_symbolizer_path]
+                    '-ids-rel', '-llvm-symbolizer', llvm_symbolizer_path,
+                    '-build-id-dir', os.path.join(SDK_ROOT, '.build-id')]
 
   logging.info('Running "%s".' % ' '.join(symbolizer_cmd))
   symbolizer_proc = subprocess.Popen(