Revert 8203: Revert 8202 - Add ragel decoder/validator to SCONS

src/trusted/validator_ragel/build.scons

Index: src/trusted/validator_ragel/build.scons
===================================================================
--- src/trusted/validator_ragel/build.scons	(revision 0)
+++ src/trusted/validator_ragel/build.scons	(revision 0)
@@ -0,0 +1,129 @@
+# -*- 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')
+
+#
+#
+# Build on x86 only.
+#
+#
+if not env.Bit('target_x86'):
+  Return()
+
+# General adjustments to the environment for builds.
+
+# TODO(khim): eliminate need for the following piece
+# See http://code.google.com/p/nativeclient/issues/detail?id=2718 for details.
+if env.Bit('windows'):
+  env.FilterOut(CCFLAGS=['/O1'])
+
+# Defines the source directory where validator generated files should be added.
+rl_src_dir = '$OBJ_ROOT/src/trusted/validator_ragel'
+val_src_dir = '$MAIN_DIR/src/trusted/validator_ragel/gen'
+
+# Source generation:
+#
+#   valgen : Regenerate any autogenerated source files.
+
+generate = False
+if ('valgen' in COMMAND_LINE_TARGETS) or ('valclean' in COMMAND_LINE_TARGETS):
+  generate = True
+
+if generate:
+  # Set of generated (source) decoder automatas.
+  automatas = []
+
+  # Source generation step 1: Build generator of ragel files.
+  #
+  # We have generator which reads .def files and produced automata definition.
+  #
+  # Ragel is included in most Linux distributions, but it's not standard tool
+  # on MacOS/Windows thus we only support gneration of automata under Linux.
+  # This also means that we don't need to make sure gen-dfa.cc is portable to
+  # non-POSIX platforms (in particular it's not Windows compatible).
+
+  env_gen_dfa = env.Clone()
+  env_gen_dfa.Append(CCFLAGS=['-std=c++0x', '-DNACL_TRUSTED_BUT_NOT_TCB'])
+
+  gen_dfa = env_gen_dfa.ComponentProgram(
+      'gen-dfa',
+      ['unreviewed/gen-dfa.cc'])
+
+  # Source generation step 2: Generate decoder automatas.
+  #
+  # Now we are back to conditionally defining the large automatas generated
+  # by gen-dfa.
+
+  # Generate 32 and 64 bit versions of decoders and validators.
+  for bits in ['32', '64']:
+    for automata in ['decoder', 'validator']:
+      # We are cheating here: there are two autogenerated files:
+      #  .rl and -consts.c, but we only track .rl one.  This is safe because
+      #  -consts.c file includes constants referenced by .rl file and if .rl
+      #  file is not changed -consts.c is guaranteed to be the same (reverse
+      #  is not true).
+      rl_file = '%s-x86_%s-instruction.rl' % (automata, bits)
+      const_file = '%s/%s-x86_%s-instruction-consts.c' % (
+          val_src_dir, automata, bits)
+      exe_path = '${STAGING_DIR}/${PROGPREFIX}gen-dfa${PROGSUFFIX}'
+      env.Command(
+          target=rl_file,
+          source=[
+            exe_path,
+            'unreviewed/general-purpose-instructions.def',
+            'unreviewed/system-instructions.def',
+            'unreviewed/x87-instructions.def',
+            'unreviewed/mmx-instructions.def',
+            'unreviewed/xmm-instructions.def',
+            'unreviewed/nops.def'],
+          action=[('${SOURCES[0]} -o ${TARGET} -c %s -m %s -d %s ${SOURCES[1]} '
+            '${SOURCES[2]} ${SOURCES[3]} ${SOURCES[4]} ${SOURCES[5]} '
+            '${SOURCES[6]}') % (
+            # Const file (-c): not tracked by SCONS (see above)
+            const_file,
+            # Argument for CPU type (-m): either "ia32" or "amd64".
+            {'32': 'ia32', '64': 'amd64'}[bits],
+            # Argument for actions selection (-d): selects only actions we need.
+            {'decoder32':
+              'check_access,opcode,parse_operands_states,mark_data_fields',
+             'decoder64':
+              'check_access,opcode,parse_operands_states,mark_data_fields',
+             'validator32':
+              ('check_access,opcode,parse_operands,parse_operands_states,'
+               'instruction_name,mark_data_fields,nacl-forbidden,'
+               'imm_operand_action,rel_operand_action'),
+             'validator64':
+              ('opcode,instruction_name,mark_data_fields,rel_operand_action,'
+               'nacl-forbidden')}[automata+bits])]
+      )
+      automatas.append(rl_file)
+      c_file = '%s/%s-x86_%s.c' % (val_src_dir, automata, bits)
+      env.Command(
+          target=c_file,
+          source=['unreviewed/%s-x86_%s.rl' % (automata, bits), rl_file],
+          action=['ragel -G2 -I%s ${SOURCES[0]} -o ${TARGET}' % (rl_src_dir)]
+      )
+      automatas.append(c_file)
+
+  # Generate 32 and 64 bit versions of decoders and validators
+  env.AlwaysBuild(env.Alias('valgen', automatas))
+  env.AlwaysBuild(env.Alias('valclean', action=[Delete(x) for x in automatas]))
+
+# Generate 32 and 64 bit versions of decoders and validators.
+for bits in ['32', '64']:
+  for automata in ['decoder', 'validator']:
+    env.ComponentLibrary('%s_x86_%s' % (automata, bits),
+                         ['gen/%s-x86_%s.c' % (automata, bits)])
+
+env.ComponentProgram(
+    'decoder-test',
+    ['unreviewed/decoder-test.c'],
+    EXTRA_LIBS=['decoder_x86_32', 'decoder_x86_64'])
+
+env.ComponentProgram(
+    'validator-test',
+    ['unreviewed/validator-test.c'],
+    EXTRA_LIBS=['validator_x86_32', 'validator_x86_64'])