IRT: Replace __attribute__((constructor)) with explicit call in _start()

src/untrusted/irt/nacl.scons

 # -*- python -*-
 # Copyright (c) 2012 The Native Client 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('env')
 
 # TODO(mseaborn): Enable -Wstrict-prototypes here.  Currently
 # dlmalloc/malloc.c does not build with this warning.
 env.FilterOut(CFLAGS=['-Wstrict-prototypes'])
 
 # This module shouldn't be built in an environment that uses glibc.
 if env.Bit('nacl_glibc'):
   raise UserError('src/untrusted/irt/nacl.scons in the wrong environment?')
 
 blob_env = env.Clone()
 blob_env.Append(LINKFLAGS=[blob_env.RodataSwitch('${IRT_BLOB_DATA_START}'),
                            blob_env.TextSwitch('${IRT_BLOB_CODE_START}')])
 
 irt_support_sources = [
+    'irt_entry.c',
     'irt_malloc.c',
     'irt_private_pthread.c',
     'irt_private_tls.c',
     ]
 
-irt_entry_obj = blob_env.ComponentObject('irt_entry.c')
-
 # NACL_GC_WRAP_SYSCALL uses ({...}) syntax.
 blob_env.FilterOut(CCFLAGS=['-pedantic'])
 
 irt_common_interfaces = [
     'irt_basic.c',
     'irt_fdio.c',
     'irt_filename.c',
     'irt_memory.c',
     'irt_dyncode.c',
     'irt_thread.c',
@@ skipping 37 matching lines @@
   # Publish the object file for tests/irt_private_pthread to use.
   # Putting aeabi_read_tp.o into libirt_support_private is not
   # sufficient because of link ordering issues.
   env.Replicate('${STAGING_DIR}', read_tp_obj)
 
 # Build a library so that irt_support_objs can be used in tests that
 # cover IRT-internal code.
 env.ComponentLibrary('libirt_support_private', irt_support_objs)
 
 irt_nonbrowser = ['irt_interfaces.c',
-                  'irt_core_entry.c',
                   'irt_core_resource.c',
                   ]
 
 irt_libs = ['srpc',
             'imc_syscalls',
             'platform',
             'gio',
             'm',
             ]
 
 irt_core_library = blob_env.ComponentProgram(
-    'irt_core',
-    [irt_entry_obj] + irt_support_objs + irt_nonbrowser,
-    EXTRA_LIBS=irt_libs)
+    'irt_core', irt_support_objs + irt_nonbrowser, EXTRA_LIBS=irt_libs)
 env.SDKInstallBin('irt_core.nexe', irt_core_library)
 
 # TODO(mcgrathr): these should be installed, but scons is a mystery
 #env.AddHeaderToSdk(['irt.h'])
 #env.AddHeaderToSdk(['irt_ppapi.h'])
 
 # Make sure that the linked IRT nexe never uses TLS via the TLS ABI
 # register (e.g., %gs on x86-32).  All IRT code must avoid direct use
 # of the TLS ABI register, which is reserved for user TLS.  Instead,
 # ensure all TLS accesses use a call to __nacl_read_tp (or __aeabi_read_tp
 # for ARM), which the IRT code overrides to segregate IRT-private TLS
 # from user TLS.
 if ((env.Bit('build_arm') or env.Bit('build_x86_32'))
     # Do not try to run OBJDUMP if 'built_elsewhere', since that *might*
     # mean that a toolchain is not even present. E.g., the arm buildbots
     # do not have the pnacl toolchain, since that is built for x86 hosts.
     and not env.Bit('built_elsewhere')):
   check_tls_arch = '${TARGET_FULLARCH}'
   if env.Bit('build_arm'):
     check_tls_arch = 'arm'
   node = env.CommandTest('irt_core_tls_test.out',
                          ['${PYTHON}', env.File('check_tls.py'),
                           check_tls_arch, '${OBJDUMP}', irt_core_library],
                          # don't run ${PYTHON} under the emulator.
                          direct_emulation=False)
   env.AddNodeToTestSuite(node, ['small_tests'], 'run_irt_core_tls_test')