[NaCl SDK] remove --toolchain option from create_nmf.

This simplifies the create_nmf invocations in our example
Makefiles.

The --toolchain option was only needed to determin if an
executable is dynamic or not (e.g. if it was built with
glibc toolchain or not).  With this change create_nmf now
knows enough about the elf headers to determine this
on its own.

The -t/--toolchain is now deprecated (but not removed
in case anyone was using it).

R=binji
BUG=


Review URL: https://chromiumcodereview.appspot.com/11348287

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@170267 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 110 insertions, 81 deletions

diff --git a/native_client_sdk/src/build_tools/make_rules.py b/native_client_sdk/src/build_tools/make_rules.py
index d7f9c0e..ad5c819 100755
--- a/native_client_sdk/src/build_tools/make_rules.py
+++ b/native_client_sdk/src/build_tools/make_rules.py
@@ -16,7 +16,6 @@ NEWLIB_CC?=$(TC_PATH)/$(OSNAME)_x86_newlib/bin/i686-nacl-gcc -c
 NEWLIB_CXX?=$(TC_PATH)/$(OSNAME)_x86_newlib/bin/i686-nacl-g++ -c
 NEWLIB_LINK?=$(TC_PATH)/$(OSNAME)_x86_newlib/bin/i686-nacl-g++ -Wl,-as-needed
 NEWLIB_LIB?=$(TC_PATH)/$(OSNAME)_x86_newlib/bin/i686-nacl-ar r
-NEWLIB_DUMP?=$(TC_PATH)/$(OSNAME)_x86_newlib/x86_64-nacl/bin/objdump
 NEWLIB_CCFLAGS?=-MMD -pthread $(NACL_WARNINGS) -idirafter $(NACL_SDK_ROOT)/include
 NEWLIB_LDFLAGS?=-pthread
 """
@@ -38,7 +37,6 @@ PNACL_CC?=$(TC_PATH)/$(OSNAME)_x86_pnacl/newlib/bin/pnacl-clang -c
 PNACL_CXX?=$(TC_PATH)/$(OSNAME)_x86_pnacl/newlib/bin/pnacl-clang++ -c
 PNACL_LINK?=$(TC_PATH)/$(OSNAME)_x86_pnacl/newlib/bin/pnacl-clang++
 PNACL_LIB?=$(TC_PATH)/$(OSNAME)_x86_pnacl/newlib/bin/pnacl-ar r
-PNACL_DUMP?=$(TC_PATH)/$(OSNAME)_x86_pnacl/newlib/bin/objdump
 PNACL_CCFLAGS?=-MMD -pthread $(NACL_WARNINGS) -idirafter $(NACL_SDK_ROOT)/include
 PNACL_LDFLAGS?=-pthread
 TRANSLATE:=$(TC_PATH)/$(OSNAME)_x86_pnacl/newlib/bin/pnacl-translate
@@ -141,7 +139,7 @@ WIN_LIB_RULES = {
 #
 NMF_RULE = """
 <tc>/<config>/<proj>.nmf : <NMF_TARGETS>
-<TAB>$(NMF) -D $(<DUMP>) -o $@ $^ -t <tc> -s <tc>/<config>
+<TAB>$(NMF) -o $@ $^ -s <tc>/<config>
 """
 
 NMF_EMPTY = """
@@ -151,7 +149,7 @@ NMF_EMPTY = """
 
 GLIBC_NMF_RULE = """
 <tc>/<config>/<proj>.nmf : <NMF_TARGETS>
-<TAB>$(NMF) -D $(<DUMP>) -o $@ $(GLIBC_PATHS) $^ -t <tc> -s <tc>/<config> $(GLIBC_REMAP)
+<TAB>$(NMF) -D $(<OBJDUMP>) -o $@ $(GLIBC_PATHS) $^ -s <tc>/<config> $(GLIBC_REMAP)
 """
 
 EXT_MAP = {
@@ -428,7 +426,6 @@ class MakeRules(object):
       tcname = tc
     self.vars['<CC>'] = '%s_CC' % TC
     self.vars['<CXX>'] = '%s_CXX' % TC
-    self.vars['<DUMP>'] = '%s_DUMP' % TC
     self.vars['<LIB>'] = '%s_LIB' % TC
     self.vars['<LINK>'] = '%s_LINK' % TC
     self.vars['<tc>'] = tc
@@ -489,10 +486,11 @@ def GenerateNMFRules(tc, main, dlls, cfg, arches):
   for arch in arches:
     replace = {
       '<config>' : cfg,
-      '<DUMP>' : '%s_DUMP' % tc.upper(),
       '<TAB>' : '\t',
       '<tc>' : tc
     }
+    if tc == 'glibc':
+      replace['<OBJDUMP>'] = 'GLIBC_DUMP'
     if '<ARCH>' in arch:
       replace['<ARCH>'] = arch['<ARCH>']
     for dll in dlls:
diff --git a/native_client_sdk/src/tools/create_nmf.py b/native_client_sdk/src/tools/create_nmf.py
index 2f8654f..4ece60a 100755
--- a/native_client_sdk/src/tools/create_nmf.py
+++ b/native_client_sdk/src/tools/create_nmf.py
@@ -85,6 +85,91 @@ class Error(Exception):
   pass
 
 
+def ParseElfHeader(path):
+  """Determine properties of a nexe by parsing elf header.
+  Return tuple of architecture and boolean signalling whether
+  the executable is dynamic (has INTERP header) or static.
+  """
+  # From elf.h:
+  # typedef struct
+  # {
+  #   unsigned char e_ident[EI_NIDENT]; /* Magic number and other info */
+  #   Elf64_Half e_type; /* Object file type */
+  #   Elf64_Half e_machine; /* Architecture */
+  #   ...
+  # } Elf32_Ehdr;
+  elf_header_format = '16s2H'
+  elf_header_size = struct.calcsize(elf_header_format)
+
+  with open(path, 'rb') as f:
+    header = f.read(elf_header_size)
+
+  header = struct.unpack(elf_header_format, header)
+  e_ident, _, e_machine = header[:3]
+
+  elf_magic = '\x7fELF'
+  if e_ident[:4] != elf_magic:
+    raise Error("Not a valid NaCL executable: %s" % path)
+
+  e_machine_mapping = {
+    3 : 'x86-32',
+    40 : 'arm',
+    62 : 'x86-64'
+  }
+  if e_machine not in e_machine_mapping:
+    raise Error("Unknown machine type: %s" % e_machine)
+
+  # Set arch based on the machine type in the elf header
+  arch = e_machine_mapping[e_machine]
+
+  # Now read the full header in either 64bit or 32bit mode
+  if arch == 'x86-64':
+    elf_header_format = '16s2HI3lI3H'
+  else:
+    elf_header_format = '16s2HI3II3H'
+
+  dynamic = IsDynamicElf(path, elf_header_format)
+  return arch, dynamic
+
+
+def IsDynamicElf(path, elf_header_format):
+  """Examine an elf file to determine if it is dynamically
+  linked or not.
+  This is determined by searching the program headers for
+  a header of type PT_INTERP.
+  """
+  elf_header_size = struct.calcsize(elf_header_format)
+
+  with open(path, 'rb') as f:
+    header = f.read(elf_header_size)
+    header = struct.unpack(elf_header_format, header)
+    p_header_offset = header[5]
+    p_header_entry_size = header[9]
+    num_p_header = header[10]
+    f.seek(p_header_offset)
+    p_headers = f.read(p_header_entry_size*num_p_header)
+
+  # Read the first word of each Phdr to find out its type.
+  #
+  # typedef struct
+  # {
+  #   Elf32_Word  p_type;     /* Segment type */
+  #   ...
+  # } Elf32_Phdr;
+  elf_phdr_format = 'I'
+  PT_INTERP = 3
+
+  while p_headers:
+    p_header = p_headers[:p_header_entry_size]
+    p_headers = p_headers[p_header_entry_size:]
+    phdr_type = struct.unpack(elf_phdr_format, p_header[:4])[0]
+    if phdr_type == PT_INTERP:
+      return True
+
+  return False
+
+
+
 class ArchFile(object):
   '''Simple structure containing information about
 
@@ -101,41 +186,7 @@ class ArchFile(object):
     self.url = url
     self.arch = arch
     if arch is None:
-      self._ReadElfHeader()
-
-  def _ReadElfHeader(self):
-    """Determine architecture of nexe by reading elf header."""
-    # From elf.h:
-    # typedef struct
-    # {
-    #   unsigned char e_ident[EI_NIDENT]; /* Magic number and other info */
-    #   Elf64_Half e_type; /* Object file type */
-    #   Elf64_Half e_machine; /* Architecture */
-    #   ...
-    # } Elf32_Ehdr;
-    elf_header_format = '16s2H'
-    elf_header_size = struct.calcsize(elf_header_format)
-
-    with open(self.path, 'rb') as f:
-      header = f.read(elf_header_size)
-
-    header = struct.unpack(elf_header_format, header)
-    e_ident, _, e_machine = header
-
-    elf_magic = '\x7fELF'
-    if e_ident[:4] != elf_magic:
-      raise Error("Not a valid NaCL executable: %s" % self.path)
-
-    e_machine_mapping = {
-      3 : 'x86-32',
-      40 : 'arm',
-      62 : 'x86-64'
-    }
-    if e_machine not in e_machine_mapping:
-      raise Error("Unknown machine type: %s" % e_machine)
-
-    # set arch based on the machine type in the elf header
-    self.arch = e_machine_mapping[e_machine]
+      self.arch = ParseElfHeader(path)[0]
 
   def __repr__(self):
     return "<ArchFile %s>" % self.path
@@ -155,7 +206,7 @@ class NmfUtils(object):
 
   def __init__(self, main_files=None, objdump=None,
                lib_path=None, extra_files=None, lib_prefix=None,
-               toolchain=None, remap=None):
+               remap=None):
     '''Constructor
 
     Args:
@@ -167,8 +218,6 @@ class NmfUtils(object):
       lib_prefix: A list of path components to prepend to the library paths,
           both for staging the libraries and for inclusion into the nmf file.
           Examples:  ['..'], ['lib_dir']
-      toolchain: Specify which toolchain newlib|glibc|pnacl which can require
-          different forms of the NMF.
       remap: Remaps the library name in the manifest.
       '''
     self.objdump = objdump
@@ -178,10 +227,8 @@ class NmfUtils(object):
     self.manifest = None
     self.needed = {}
     self.lib_prefix = lib_prefix or []
-    self.toolchain = toolchain
     self.remap = remap or {}
 
-
   def GleanFromObjdump(self, files):
     '''Get architecture and dependency information for given files
 
@@ -209,11 +256,15 @@ class NmfUtils(object):
     input_info = {}
     needed = set()
     output, err_output = proc.communicate()
+    if proc.returncode:
+      raise Error('%s\nStdError=%s\nobjdump failed with error code: %d' %
+                  (output, err_output, proc.returncode))
+
     for line in output.splitlines(True):
       # Objdump should display the architecture first and then the dependencies
       # second for each file in the list.
       matched = FormatMatcher.match(line)
-      if matched is not None:
+      if matched:
         filename = matched.group(1)
         arch = OBJDUMP_ARCH_MAP[matched.group(2)]
         if files[filename] is None or arch in files[filename]:
@@ -224,13 +275,9 @@ class NmfUtils(object):
               path=filename,
               url='/'.join(self.lib_prefix + [ARCH_LOCATION[arch], name]))
       matched = NeededMatcher.match(line)
-      if matched is not None:
+      if matched:
         if files[filename] is None or arch in files[filename]:
           needed.add('/'.join([arch, matched.group(1)]))
-    status = proc.poll()
-    if status != 0:
-      raise Error('%s\nStdError=%s\nobjdump failed with error code: %d' %
-                  (output, err_output, status))
     return input_info, needed
 
   def FindLibsInPath(self, name):
@@ -261,10 +308,11 @@ class NmfUtils(object):
     if self.needed:
       return self.needed
 
-    runnable = (self.toolchain != 'newlib' and self.toolchain != 'pnacl')
     DebugPrint('GetNeeded(%s)' % self.main_files)
 
-    if runnable:
+    dynamic = any(ParseElfHeader(f)[1] for f in self.main_files)
+
+    if dynamic:
       examined = set()
       all_files, unexamined = self.GleanFromObjdump(
           dict([(f, None) for f in self.main_files]))
@@ -335,9 +383,11 @@ class NmfUtils(object):
     FILES key mapped as 'main.exe' instead of it's original name so that the
     loader can find it.'''
     manifest = { FILES_KEY: {}, PROGRAM_KEY: {} }
-    runnable = (self.toolchain != 'newlib' and self.toolchain != 'pnacl')
 
     needed = self.GetNeeded()
+
+    runnable = any(n.endswith(RUNNABLE_LD) for n in needed)
+
     for need, archinfo in needed.items():
       urlinfo = { URL_KEY: archinfo.url }
       name = archinfo.name
@@ -383,19 +433,6 @@ class NmfUtils(object):
     return '\n'.join([line.rstrip() for line in pretty_lines]) + '\n'
 
 
-def DetermineToolchain(objdump):
-  objdump = objdump.replace('\\', '/')
-  paths = objdump.split('/')
-  count = len(paths)
-  for index in range(count - 2, 0, -1):
-    if paths[index] == 'toolchain':
-      if paths[index + 1].endswith('newlib'):
-        return 'newlib'
-      if paths[index + 1].endswith('glibc'):
-        return 'glibc'
-  raise Error('Could not deternime which toolchain to use.')
-
-
 def Trace(msg):
   if Trace.verbose:
     sys.stderr.write(str(msg) + '\n')
@@ -403,7 +440,7 @@ def Trace(msg):
 Trace.verbose = False
 
 
-def Main(argv):
+def main(argv):
   parser = optparse.OptionParser(
       usage='Usage: %prog [options] nexe [extra_libs...]')
   parser.add_option('-o', '--output', dest='output',
@@ -425,9 +462,7 @@ def Main(argv):
   parser.add_option('-r', '--remove', dest='remove',
                     help='Remove the prefix from the files.',
                     metavar='PATH')
-  parser.add_option('-t', '--toolchain', dest='toolchain',
-                    help='Add DIRECTORY to library search path',
-                    default=None, metavar='TOOLCHAIN')
+  parser.add_option('-t', '--toolchain', help='Legacy option, do not use')
   parser.add_option('-n', '--name', dest='name',
                     help='Rename FOO as BAR',
                     action='append', default=[], metavar='FOO,BAR')
@@ -435,21 +470,18 @@ def Main(argv):
                     help='Verbose output', action='store_true')
   parser.add_option('-d', '--debug-mode',
                     help='Debug mode', action='store_true')
-  (options, args) = parser.parse_args(argv)
+  options, args = parser.parse_args(argv)
   if options.verbose:
     Trace.verbose = True
   if options.debug_mode:
     DebugPrint.debug_mode = True
 
+  if options.toolchain is not None:
+    print "warning: option -t/--toolchain is deprecated."
+
   if len(args) < 1:
     raise Error("No nexe files specified.  See --help for more info")
 
-  if not options.toolchain:
-    options.toolchain = DetermineToolchain(os.path.abspath(options.objdump))
-
-  if options.toolchain not in ['newlib', 'glibc', 'pnacl']:
-    raise Error('Unknown toolchain: ' + str(options.toolchain))
-
   remap = {}
   for ren in options.name:
     parts = ren.split(',')
@@ -466,7 +498,6 @@ def Main(argv):
                  main_files=args,
                  lib_path=options.lib_path,
                  lib_prefix=path_prefix,
-                 toolchain=options.toolchain,
                  remap=remap)
 
   nmf.GetManifest()
@@ -486,7 +517,7 @@ def Main(argv):
 # Invoke this file directly for simple testing.
 if __name__ == '__main__':
   try:
-    rtn = Main(sys.argv[1:])
+    rtn = main(sys.argv[1:])
   except Error, e:
     sys.stderr.write("%s: %s\n" % (os.path.basename(__file__), e))
     rtn = 1