offlineasm/settings.rb

   1 # Copyright (C) 2011 Apple Inc. All rights reserved.
   2 #
   3 # Redistribution and use in source and binary forms, with or without
   4 # modification, are permitted provided that the following conditions
   5 # are met:
   6 # 1. Redistributions of source code must retain the above copyright
   7 #    notice, this list of conditions and the following disclaimer.
   8 # 2. Redistributions in binary form must reproduce the above copyright
   9 #    notice, this list of conditions and the following disclaimer in the
  10 #    documentation and/or other materials provided with the distribution.
  11 #
  12 # THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
  13 # AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  14 # THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  15 # PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
  16 # BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  17 # CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  18 # SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  19 # INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  20 # CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  21 # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  22 # THE POSSIBILITY OF SUCH DAMAGE.
  23
  24 require "ast"
  25 require "backends"
  26 require "parser"
  27 require "transform"
  28
  29 #
  30 # computeSettingsCombinations(ast) -> settingsCombiations
  31 #
  32 # Computes an array of settings maps, where a settings map constitutes
  33 # a configuration for the assembly code being generated. The map
  34 # contains key value pairs where keys are settings names (strings) and
  35 # the values are booleans (true for enabled, false for disabled).
  36 #
  37
  38 def computeSettingsCombinations(ast)
  39     settingsCombinations = []
  40
  41     def settingsCombinator(settingsCombinations, mapSoFar, remaining)
  42         if remaining.empty?
  43             settingsCombinations << mapSoFar
  44             return
  45         end
  46
  47         newMap = mapSoFar.dup
  48         newMap[remaining[0]] = true
  49         settingsCombinator(settingsCombinations, newMap, remaining[1..-1])
  50
  51         newMap = mapSoFar.dup
  52         newMap[remaining[0]] = false
  53         settingsCombinator(settingsCombinations, newMap, remaining[1..-1])
  54     end
  55
  56     settingsCombinator(settingsCombinations, {}, (ast.filter(Setting).uniq.collect{|v| v.name} + BACKENDS).uniq)
  57
  58     settingsCombinations
  59 end
  60
  61 #
  62 # forSettings(concreteSettings, ast) {
  63 #     | concreteSettings, lowLevelAST, backend | ... }
  64 #
  65 # Determines if the settings combination is valid, and if so, calls
  66 # the block with the information you need to generate code.
  67 #
  68
  69 def forSettings(concreteSettings, ast)
  70     # Check which architectures this combinator claims to support.
  71     numClaimedBackends = 0
  72     selectedBackend = nil
  73     BACKENDS.each {
  74         | backend |
  75         isSupported = concreteSettings[backend]
  76         raise unless isSupported != nil
  77         numClaimedBackends += if isSupported then 1 else 0 end
  78         if isSupported
  79             selectedBackend = backend
  80         end
  81     }
  82
  83     return if numClaimedBackends > 1
  84
  85     # Resolve the AST down to a low-level form (no macros or conditionals).
  86     lowLevelAST = ast.resolveSettings(concreteSettings)
  87
  88     yield concreteSettings, lowLevelAST, selectedBackend
  89 end
  90
  91 #
  92 # forEachValidSettingsCombination(ast) {
  93 #     | concreteSettings, ast, backend, index | ... }
  94 #
  95 # forEachValidSettingsCombination(ast, settingsCombinations) {
  96 #     | concreteSettings, ast, backend, index | ... }
  97 #
  98 # Executes the given block for each valid settings combination in the
  99 # settings map. The ast passed into the block is resolved
 100 # (ast.resolve) against the settings.
 101 #
 102 # The first form will call computeSettingsCombinations(ast) for you.
 103 #
 104
 105 def forEachValidSettingsCombination(ast, *optionalSettingsCombinations)
 106     raise if optionalSettingsCombinations.size > 1
 107
 108     if optionalSettingsCombinations.empty?
 109         settingsCombinations = computeSettingsCombinations(ast)
 110     else
 111         settingsCombinations = optionalSettingsCombiations[0]
 112     end
 113
 114     settingsCombinations.each_with_index {
 115         | concreteSettings, index |
 116         forSettings(concreteSettings, ast) {
 117             | concreteSettings_, lowLevelAST, backend |
 118             yield concreteSettings, lowLevelAST, backend, index
 119         }
 120     }
 121 end
 122
 123 #
 124 # cppSettingsTest(concreteSettings)
 125 #
 126 # Returns the C++ code used to test if we are in a configuration that
 127 # corresponds to the given concrete settings.
 128 #
 129
 130 def cppSettingsTest(concreteSettings)
 131     "#if " + concreteSettings.to_a.collect{
 132         | pair |
 133         (if pair[1]
 134              ""
 135          else
 136              "!"
 137          end) + "OFFLINE_ASM_" + pair[0]
 138     }.join(" && ")
 139 end
 140
 141 #
 142 # isASTErroneous(ast)
 143 #
 144 # Tests to see if the AST claims that there is an error - i.e. if the
 145 # user's code, after settings resolution, has Error nodes.
 146 #
 147
 148 def isASTErroneous(ast)
 149     not ast.filter(Error).empty?
 150 end
 151
 152 #
 153 # assertConfiguration(concreteSettings)
 154 #
 155 # Emits a check that asserts that we're using the given configuration.
 156 #
 157
 158 def assertConfiguration(concreteSettings)
 159     $output.puts cppSettingsTest(concreteSettings)
 160     $output.puts "#else"
 161     $output.puts "#error \"Configuration mismatch.\""
 162     $output.puts "#endif"
 163 end
 164
 165 #
 166 # emitCodeInConfiguration(concreteSettings, ast, backend) {
 167 #     | concreteSettings, ast, backend | ... }
 168 #
 169 # Emits all relevant guards to see if the configuration holds and
 170 # calls the block if the configuration is not erroneous.
 171 #
 172
 173 def emitCodeInConfiguration(concreteSettings, ast, backend)
 174     $output.puts cppSettingsTest(concreteSettings)
 175
 176     if isASTErroneous(ast)
 177         $output.puts "#error \"Invalid configuration.\""
 178     elsif not WORKING_BACKENDS.include? backend
 179         $output.puts "#error \"This backend is not supported yet.\""
 180     else
 181         yield concreteSettings, ast, backend
 182     end
 183
 184     $output.puts "#endif"
 185 end
 186
 187 #
 188 # emitCodeInAllConfigurations(ast) {
 189 #     | concreteSettings, ast, backend, index | ... }
 190 #
 191 # Emits guard codes for all valid configurations, and calls the block
 192 # for those configurations that are valid and not erroneous.
 193 #
 194
 195 def emitCodeInAllConfigurations(ast)
 196     forEachValidSettingsCombination(ast) {
 197         | concreteSettings, lowLevelAST, backend, index |
 198         $output.puts cppSettingsTest(concreteSettings)
 199         yield concreteSettings, lowLevelAST, backend, index
 200         $output.puts "#endif"
 201     }
 202 end
 203
 204
 205