Moving dgen_ scripts out of validator_arm into a common directory.

src/trusted/validator_arm/dgen_decoder_output.py

-#!/usr/bin/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.
-#
-
-"""
-Responsible for generating the decoder based on parsed
-table representations.
-"""
-
-
-import dgen_opt
-import dgen_output
-
-# This file generates the class decoder Decoder as defined by the
-# decoder tables.  The code is specifically written to minimize the
-# number of decoder classes needed to parse valid ARM
-# instructions. Many rows in the table use the same decoder class. In
-# addition, we optimize tables by merging, so long as the same decoder
-# class is built.
-#
-# The following files are generated:
-#
-#     decoder.h
-#     decoder.cc
-#
-# decoder.h declares the generated decoder parser class while
-# decoder.cc contains the implementation of that decoder class.
-#
-# For testing purposes (see dgen_test_output.py) different rules are
-# applied. Note: It may be worth reading dgen_test_output.py preamble
-# to get a better understanding of decoder actions, and why we need
-# the "action_filter" methods.
-
-# Defines the header for decoder.h
-H_HEADER="""
-%(FILE_HEADER)s
-
-#ifndef %(IFDEF_NAME)s
-#define %(IFDEF_NAME)s
-
-#include "native_client/src/trusted/validator_arm/decode.h"
-#include "native_client/src/trusted/validator_arm/inst_classes.h"
-
-namespace nacl_arm_dec {
-"""
-
-DECODER_DECLARE_HEADER="""
-// Defines a decoder class selector for instructions.
-class %(decoder_name)s : DecoderState {
- public:
-   explicit %(decoder_name)s();
-   virtual ~%(decoder_name)s();
-
-   // Parses the given instruction, returning the decoder to use.
-   virtual const ClassDecoder& decode(const Instruction) const;
-
- private:
-"""
-
-DECODER_DECLARE_METHOD_COMMENTS="""
-  // The following list of methods correspond to each decoder table,
-  // and implements the pattern matching of the corresponding bit
-  // patterns. After matching the corresponding bit patterns, they
-  // either call other methods in this list (corresponding to another
-  // decoder table), or they return the instance field that implements
-  // the class decoder that should be used to decode the particular
-  // instruction.
-"""
-
-DECODER_DECLARE_METHOD="""
-  inline const ClassDecoder& decode_%(table_name)s(
-      const Instruction insn) const;
-"""
-
-DECODER_DECLARE_FIELD_COMMENTS="""
-  // The following fields define the set of class decoders
-  // that can be returned by the API function "decode". They
-  // are created once as instance fields, and then returned
-  // by the table methods above. This speeds up the code since
-  // the class decoders need to only be built once (and reused
-  // for each call to "decode").
-"""
-
-DECODER_DECLARE_FIELD="""
-  const %(decoder)s %(decoder)s_instance_;
-"""
-
-DECODER_DECLARE_FOOTER="""
-};
-"""
-
-H_FOOTER="""
-}  // namespace nacl_arm_dec
-#endif  // %(IFDEF_NAME)s
-"""
-
-def generate_h(decoder, decoder_name, filename, out):
-    """Entry point to the decoder for .h file.
-
-    Args:
-        decoder: The decoder defined by the list of Table objects to process.
-        decoder_name: The name of the decoder state to build.
-        filename: The (localized) name for the .h file.
-        named_decoders: If true, generate a decoder state with named instances.
-        out: a COutput object to write to.
-    """
-    if not decoder.primary: raise Exception('No tables provided.')
-
-    # Before starting, remove all testing information from the parsed tables.
-    decoder = decoder.action_filter(['name'])
-
-    values = {
-        'FILE_HEADER': dgen_output.HEADER_BOILERPLATE,
-        'IFDEF_NAME': dgen_output.ifdef_name(filename),
-        'decoder_name': decoder_name,
-        }
-    out.write(H_HEADER % values)
-    out.write(DECODER_DECLARE_HEADER % values)
-    out.write(DECODER_DECLARE_METHOD_COMMENTS)
-    for table in decoder.tables():
-      values['table_name'] = table.name
-      out.write(DECODER_DECLARE_METHOD % values)
-    out.write(DECODER_DECLARE_FIELD_COMMENTS)
-    for action in decoder.decoders():
-      values['decoder'] = action.name;
-      out.write(DECODER_DECLARE_FIELD % values)
-    out.write(DECODER_DECLARE_FOOTER % values)
-    out.write(H_FOOTER % values)
-
-# Defines the header for DECODER.h
-CC_HEADER="""
-%(FILE_HEADER)s
-
-#include "%(header_filename)s"
-
-#include <stdio.h>
-
-namespace nacl_arm_dec {
-
-"""
-
-CONSTRUCTOR_HEADER="""
-%(decoder_name)s::%(decoder_name)s() : DecoderState()
-"""
-
-CONSTRUCTOR_FIELD_INIT="""
-  , %(decoder)s_instance_()
-"""
-
-CONSTRUCTOR_FOOTER="""
-{}
-
-%(decoder_name)s::~%(decoder_name)s() {}
-"""
-
-METHOD_HEADER="""
-// Implementation of table: %(table_name)s.
-// Specified by: %(citation)s
-const ClassDecoder& %(decoder_name)s::decode_%(table_name)s(
-     const Instruction insn) const
-{
-"""
-
-METHOD_DISPATCH="""
-  if (%(tests)s)
-"""
-
-METHOD_DISPATCH_CLASS_DECODER="""
-    return %(decoder)s_instance_;
-"""
-
-METHOD_DISPATCH_SUBMETHOD="""
-    return decode_%(subtable_name)s(insn);
-"""
-
-METHOD_FOOTER="""
-  // Catch any attempt to fall though ...
-  fprintf(stderr, "TABLE IS INCOMPLETE: %(table_name)s could not parse %%08X",
-          insn.bits(31, 0));
-  return Forbidden_instance_;
-}
-"""
-
-DECODER_METHOD="""
-const ClassDecoder& %(decoder_name)s::decode(const Instruction insn) const {
-  return decode_%(entry_table_name)s(insn);
-}
-"""
-
-CC_FOOTER="""
-}  // namespace nacl_arm_dec
-"""
-
-def generate_cc(decoder, decoder_name, filename, out):
-    """Implementation of the decoder in .cc file
-
-    Args:
-        decoder: The decoder defined by the list of Table objects to process.
-        decoder_name: The name of the decoder state to build.
-        filename: The (localized) name for the .h file.
-        named_decoders: If true, generate a decoder state with named instances.
-        out: a COutput object to write to.
-    """
-    if not decoder.primary: raise Exception('No tables provided.')
-    assert filename.endswith('.cc')
-
-    # Before starting, remove all testing information from the parsed tables.
-    decoder = decoder.action_filter(['name'])
-    values = {
-        'FILE_HEADER': dgen_output.HEADER_BOILERPLATE,
-        'header_filename': filename[:-2] + 'h',
-        'decoder_name': decoder_name,
-        'entry_table_name': decoder.primary.name,
-        }
-    out.write(CC_HEADER % values)
-    _generate_constructors(decoder, values, out)
-    _generate_methods(decoder, values, out)
-    out.write(DECODER_METHOD % values)
-    out.write(CC_FOOTER % values)
-
-def _generate_constructors(decoder, values, out):
-  out.write(CONSTRUCTOR_HEADER % values)
-  for decoder in decoder.decoders():
-    values['decoder'] = decoder.name
-    out.write(CONSTRUCTOR_FIELD_INIT % values)
-  out.write(CONSTRUCTOR_FOOTER % values)
-
-def _generate_methods(decoder, values, out):
-  for table in decoder.tables():
-    opt_rows = sorted(dgen_opt.optimize_rows(table.rows))
-    print ("Table %s: %d rows minimized to %d"
-           % (table.name, len(table.rows), len(opt_rows)))
-
-    values['table_name'] = table.name
-    values['citation'] = table.citation
-    out.write(METHOD_HEADER % values)
-
-    # Add message to stop compilation warnings if this table
-    # doesn't require subtables to select a class decoder.
-    if not [r for r in opt_rows
-            if r.action.__class__.__name__ == 'DecoderMethod']:
-      out.write("  UNREFERENCED_PARAMETER(insn);")
-
-    for row in opt_rows:
-      # Each row consists of a set of bit patterns defining if the row
-      # is applicable. Convert this into a sequence of anded C test
-      # expressions. For example, convert the following pair of bit
-      # patterns:
-      #
-      #   xxxx1010xxxxxxxxxxxxxxxxxxxxxxxx
-      #   xxxxxxxxxxxxxxxxxxxxxxxxxxxx0101
-      #
-      # Each instruction is masked to get the the bits, and then
-      # tested against the corresponding expected bits. Hence, the
-      # above example is converted to:
-      #
-      #    ((insn & 0x0F000000) != 0x0C000000) &&
-      #    ((insn & 0x0000000F) != 0x00000005)
-      values['tests'] = ' && '.join(["(%s)" % p.to_c_expr('insn')
-                                     for p in row.patterns])
-      out.write(METHOD_DISPATCH % values)
-      if row.action.__class__.__name__ == 'DecoderAction':
-        values['decoder'] = row.action.name
-        out.write(METHOD_DISPATCH_CLASS_DECODER % values)
-      elif row.action.__class__.__name__ == 'DecoderMethod':
-        values['subtable_name'] = row.action.name
-        out.write(METHOD_DISPATCH_SUBMETHOD % values)
-      else:
-        raise Exception('Bad table action: %s' % repr(row.action))
-    out.write(METHOD_FOOTER % values)