Add ragel machine generators to SCONS

src/trusted/validator_ragel/build.scons

+# -*- python -*-
+# Copyright (c) 2011 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 os
+import sys
+Import('env')
+
+#
+#
+# Build on x86 only.
+#
+#
+if not env.Bit('target_x86'): Return()
+
+# ------------------------------------------------------
+# General adjustments to the environment for builds.
+
+# Make a copy of debug CRT for now.
+# TODO(bradnelson): there should be a better way to generalize this requirement.
+# NOTE: debug builds on windows break without this
+crt = []
+if env.AllBits('windows', 'debug'):
+  for i in ['.', '$STAGING_DIR']:
+    crt += env.Replicate(i, '$VC80_DIR/vc/redist/Debug_NonRedist/'
+                         'x86/Microsoft.VC80.DebugCRT')
+    crt += env.Replicate(i, '$VC80_DIR/vc/redist/x86/Microsoft.VC80.CRT')
+
+# TODO(bradchen): eliminate need for the following line
+env.FilterOut(CCFLAGS=['-Wextra', '-Wswitch-enum', '-Wsign-compare'])
+
+# Defines the source directory where validator generated files should be added.
+val_src_dir = '$MAIN_DIR/src/trusted/validator_ragel/generated'
+# ------------------------------------------------------
+# Source generation:
+#
+#   valgen : Regenerate any autogenerated source files.
+
+gen_env = env.Clone();
+gen_env.Append(CCFLAGS=['-DNACL_TRUSTED_BUT_NOT_TCB'])
+
+generate = False
+if 'valgen' in COMMAND_LINE_TARGETS: generate = True
+if 'valclean' in COMMAND_LINE_TARGETS: generate = True
+
+# Set of generated (source) decoder tables.
+tables = []
+
+# ------------------------------------------------------
+# Ragel generator:
+#
+# We have generator which reads .def files and produced machine definition.
+
+env_gen_decoder = env.Clone()
+env_gen_decoder.FilterOut(CCFLAGS=['-pedantic', '-Wsign-compare'])

[pasko-google - do not use, 2012/04/03 15:09:40]

filtering out these options smells wrong

+env_gen_decoder.Append(CCFLAGS=['-std=c++0x', '-O3', '-finline-limit=10000',

[pasko-google - do not use, 2012/04/03 15:09:40]

no reason for doing -O3, only reduces overall time
-finline-limit -- needs explanation in commants

[khim, 2012/04/03 16:45:53]

Done.

+                                '-Wno-sign-compare',
+                                '-DNACL_TRUSTED_BUT_NOT_TCB'])
+
+gen_decoder = env_gen_decoder.ComponentProgram(
+    'gen-decoder',
+    ['unreviewed/gen-decoder.cc'])
+
+env.Requires(gen_decoder, crt)
+
+# ------------------------------------------------------
+#  Source generation step 2: Generate decoder tables.
+#
+# Now we are back to conditionally defining the large tables generated
+# by ncdecode_tablegen.
+#
+
+if generate:
+  #
+  # Generate 32 and 64 bit versions of decoders and validators.
+  #
+  for bits in ['32', '64']:
+    for machine in ['decoder', 'validator']:
+      rl_file = '%s/%s-x86_%s-instruction.rl' % (val_src_dir, machine, bits)
+      exe_path = '${STAGING_DIR}/${PROGPREFIX}gen-decoder${PROGSUFFIX}'
+      gen_env.Command(
+          rl_file,
+          [exe_path,
+            'unreviewed/general-purpose-instructions.def',
+            'unreviewed/system-instructions.def',
+            'unreviewed/x87-instructions.def',
+            'unreviewed/mmx-instructions.def',
+            'unreviewed/xmm-instructions.def',
+            'unreviewed/nops.def'],
+          [('${SOURCES[0]} -o ${TARGET} -m %s -d %s ${SOURCES[1]} '

[pasko-google - do not use, 2012/04/03 15:09:40]

this manipulation with SOURCES scares me away since I do not know where these
SOURCES came from, is this something internal to scons? can this be done
differently using names rather than numbers?

[halyavin, 2012/04/03 15:15:12]

These are Command parameters (second argument of env.Command).

[khim, 2012/04/03 16:45:53]

Well, yeah: these are files listed immediately before that line.

can this be done
I've tried and it looks even worse. If we use SOURCES[N] then scons inself
creates FQFN, otherwise we'll need to it manually.

+            '${SOURCES[2]} ${SOURCES[3]} ${SOURCES[4]} ${SOURCES[5]} '
+            '${SOURCES[6]}') % (
+            {'32': 'ia32', '64': 'amd64'}[bits],
+            {'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'}[machine+bits])]
+      )
+      tables.append(rl_file)
+      c_file = '%s/%s-x86_%s.c' % (val_src_dir, machine, bits)
+      gen_env.Command(
+          c_file,
+          ['unreviewed/%s-x86_%s.rl' % (machine, bits), rl_file],
+          ['ragel -G2 -I%s ${SOURCES[0]} -o ${TARGET}' % (val_src_dir)]
+      )
+      tables.append(c_file)
+
+  # Generate 32 and 64 bit versions of decoders and validators
+  gen_env.AlwaysBuild(
+      gen_env.Alias('valgen', tables))
+  gen_env.AlwaysBuild(
+      gen_env.Alias('valclean', action=[Delete(x) for x in tables]))