Add number of native relocations to .size file metadata (Reland)

In furtherance of possibly putting a limit on additional native relocations
added to the binary. A count of native relocations is now included in the
metadata of the .size file.

This reverts commit 936b6478.

Reason for reland: this cl works on 64bit elf files.

Original CL:
> https://chromium-review.googlesource.com/c/chromium/src/+/1879504

Bug: 1012373
Change-Id: I47c7fc8e73b6ad05d3ecd9dfd235f8904e9d7c9b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1889946Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Commit-Queue: Mohamed Heikal <mheikal@chromium.org>
Cr-Commit-Position: refs/heads/master@{#711261}

tools/binary_size/libsupersize/archive.py

@@ -773,6 +773,7 @@ def CreateMetadata(map_path, elf_path, apk_path, minimal_apks_path,
         elf_path))
     timestamp = calendar.timegm(timestamp_obj.timetuple())
     relative_tool_prefix = path_util.ToSrcRootRelative(tool_prefix)
+    relocations_count = _CountRelocationsFromElf(elf_path, tool_prefix)
 
     metadata = {
         models.METADATA_GIT_REVISION: git_rev,
@@ -781,6 +782,7 @@ def CreateMetadata(map_path, elf_path, apk_path, minimal_apks_path,
         models.METADATA_ELF_BUILD_ID: build_id,
         models.METADATA_LINKER_NAME: linker_name,
         models.METADATA_TOOL_PREFIX: relative_tool_prefix,
+        models.METADATA_ELF_RELOCATIONS_COUNT: relocations_count
     }
 
     if output_directory:
@@ -1671,6 +1673,13 @@ def _ArchFromElf(elf_path, tool_prefix):
   return machine
 
 
+def _CountRelocationsFromElf(elf_path, tool_prefix):
+  args = [path_util.GetObjDumpPath(tool_prefix), '--private-headers', elf_path]
+  stdout = subprocess.check_output(args)
+  relocations = re.search('REL[AR]?COUNT\s*(.+)', stdout).group(1)
+  return int(relocations, 16)
+
+
 def _ParseGnArgs(args_path):
   """Returns a list of normalized "key=value" strings."""
   args = {}

tools/binary_size/libsupersize/models.py

@@ -44,6 +44,7 @@ METADATA_ELF_ARCHITECTURE = 'elf_arch'  # "Machine" field from readelf -h
 METADATA_ELF_FILENAME = 'elf_file_name'  # Path relative to output_directory.
 METADATA_ELF_MTIME = 'elf_mtime'  # int timestamp in utc.
 METADATA_ELF_BUILD_ID = 'elf_build_id'
+METADATA_ELF_RELOCATIONS_COUNT = 'elf_relocations_count'
 METADATA_GN_ARGS = 'gn_args'
 METADATA_LINKER_NAME = 'linker_name'
 METADATA_TOOL_PREFIX = 'tool_prefix'  # Path relative to SRC_ROOT.

tools/binary_size/libsupersize/testdata/Archive_Apk.golden

@@ -4,6 +4,7 @@ elf_arch=arm
 elf_build_id=WhatAnAmazingBuildId
 elf_file_name=elf
 elf_mtime={redacted}
+elf_relocations_count=394087
 git_revision=abc123
 gn_args=var1=true var2="foo"
 linker_name=gold

tools/binary_size/libsupersize/testdata/Archive_Elf.golden

@@ -2,6 +2,7 @@ elf_arch=arm
 elf_build_id=WhatAnAmazingBuildId
 elf_file_name=elf
 elf_mtime={redacted}
+elf_relocations_count=394087
 git_revision=abc123
 gn_args=var1=true var2="foo"
 linker_name=gold

tools/binary_size/libsupersize/testdata/Archive_MinimalApks.golden

@@ -5,6 +5,7 @@ elf_arch=arm
 elf_build_id=WhatAnAmazingBuildId
 elf_file_name=elf
 elf_mtime={redacted}
+elf_relocations_count=394087
 git_revision=abc123
 gn_args=var1=true var2="foo"
 linker_name=gold

tools/binary_size/libsupersize/testdata/Archive_Pak_Files.golden

@@ -2,6 +2,7 @@ elf_arch=arm
 elf_build_id=WhatAnAmazingBuildId
 elf_file_name=elf
 elf_mtime={redacted}
+elf_relocations_count=394087
 git_revision=abc123
 gn_args=var1=true var2="foo"
 linker_name=gold

tools/binary_size/libsupersize/testdata/Console.golden

@@ -67,6 +67,7 @@ Metadata:
     elf_build_id=WhatAnAmazingBuildId
     elf_file_name=elf
     elf_mtime={redacted}
+    elf_relocations_count=394087
     git_revision=abc123
     gn_args=var1=true var2="foo"
     linker_name=gold

tools/binary_size/libsupersize/testdata/Diff_NullDiff.golden

@@ -3,6 +3,7 @@ Common Metadata:
     elf_build_id=WhatAnAmazingBuildId
     elf_file_name=elf
     elf_mtime={redacted}
+    elf_relocations_count=394087
     git_revision=abc123
     gn_args=var1=true var2="foo"
     linker_name=gold

tools/binary_size/libsupersize/testdata/FullDescription.golden

@@ -3,6 +3,7 @@ Metadata:
     elf_build_id=WhatAnAmazingBuildId
     elf_file_name=elf
     elf_mtime={redacted}
+    elf_relocations_count=394087
     git_revision=abc123
     gn_args=var1=true var2="foo"
     linker_name=gold

tools/binary_size/libsupersize/testdata/mock_toolchain/mock_objdump.py

+# Copyright 2019 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import os
+import sys
+
+_OUTPUT = """\
+{}:	file format ELF32-arm-little
+
+Program Header:
+    PHDR off    0x00000034 vaddr 0x00000034 paddr 0x00000034 align 2**2
+         filesz 0x00000160 memsz 0x00000160 flags r--
+  INTERP off    0x00000194 vaddr 0x00000194 paddr 0x00000194 align 2**0
+         filesz 0x00000013 memsz 0x00000013 flags r--
+    LOAD off    0x00000000 vaddr 0x00000000 paddr 0x00000000 align 2**12
+         filesz 0x02e86540 memsz 0x02e86540 flags r-x
+    LOAD off    0x02e86540 vaddr 0x02e87540 paddr 0x02e87540 align 2**12
+         filesz 0x0020751c memsz 0x0020751c flags rw-
+    LOAD off    0x0308da60 vaddr 0x0308fa60 paddr 0x0308fa60 align 2**12
+         filesz 0x00027048 memsz 0x0056d5bc flags rw-
+    LOAD off    0x030b5714 vaddr 0x0364d714 paddr 0x0364d714 align 2**12
+         filesz 0x00000000 memsz 0x00001000 flags rw-
+ DYNAMIC off    0x0308ce08 vaddr 0x0308de08 paddr 0x0308de08 align 2**2
+         filesz 0x000000f0 memsz 0x000000f0 flags rw-
+   RELRO off    0x02e86540 vaddr 0x02e87540 paddr 0x02e87540 align 2**0
+         filesz 0x0020751c memsz 0x00207ac0 flags r--
+   STACK off    0x00000000 vaddr 0x00000000 paddr 0x00000000 align 2**64
+         filesz 0x00000000 memsz 0x00000000 flags rw-
+    NOTE off    0x000001a8 vaddr 0x000001a8 paddr 0x000001a8 align 2**2
+         filesz 0x000000d8 memsz 0x000000d8 flags r--
+ UNKNOWN off    0x00000280 vaddr 0x00000280 paddr 0x00000280 align 2**2
+         filesz 0x00002498 memsz 0x00002498 flags r--
+
+Dynamic Section:
+  NEEDED               libdl.so
+  NEEDED               libm.so
+  NEEDED               libandroid.so
+  NEEDED               liblog.so
+  NEEDED               libjnigraphics.so
+  NEEDED               libc.so
+  SONAME               libmonochrome.so
+  FLAGS                0x00000008
+  FLAGS_1              0x00000001
+  ANDROID_REL          0x00021de8
+  ANDROID_RELSZ        0x00030b95
+  RELENT               0x00000008
+  RELCOUNT             0x00060367
+  JMPREL               0x00052980
+  PLTRELSZ             0x00000c48
+  PLTGOT               0x0308e42c
+  PLTREL               0x00000011
+  SYMTAB               0x00002718
+  SYMENT               0x00000010
+  STRTAB               0x000133a0
+  STRSZ                0x0000ea48
+  GNU_HASH             0x0000f2d0
+  INIT_ARRAY           0x0308de00
+  INIT_ARRAYSZ         0x00000008
+  FINI_ARRAY           0x02e87540
+  FINI_ARRAYSZ         0x00000008
+  VERSYM               0x0000dbd8
+  VERNEED              0x0000f270
+  VERNEEDNUM           0x00000003
+Version References:
+  required from libdl.so:
+    0x00050d63 0x00 03 LIBC
+  required from libm.so:
+    0x00050d63 0x00 04 LIBC
+  required from libc.so:
+    0x00050d63 0x00 02 LIBC
+"""
+
+
+def _PrintOutput(path):
+  sys.stdout.write(_OUTPUT.format(path))
+  sys.stdout.write('\n')
+
+
+def main():
+  paths = [p for p in sys.argv[1:] if not p.startswith('-')]
+  _PrintOutput(paths[0])
+
+
+if __name__ == '__main__':
+  main()

tools/binary_size/libsupersize/testdata/mock_toolchain/objdump

+#!/usr/bin/env bash
+# Copyright 2019 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+base_dir=$(dirname "$0")
+exec python "$base_dir/mock_objdump.py" "$@"