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 "config"
  25 require "ast"
  26 require "backends"
  27 require "parser"
  28 require "transform"
  29
  30 #
  31 # computeSettingsCombinations(ast) -> settingsCombiations
  32 #
  33 # Computes an array of settings maps, where a settings map constitutes
  34 # a configuration for the assembly code being generated. The map
  35 # contains key value pairs where keys are settings names (strings) and
  36 # the values are booleans (true for enabled, false for disabled).
  37 #
  38
  39 def computeSettingsCombinations(ast)
  40     settingsCombinations = []
  41
  42     def settingsCombinator(settingsCombinations, mapSoFar, remaining)
  43         if remaining.empty?
  44             settingsCombinations << mapSoFar
  45             return
  46         end
  47
  48         newMap = mapSoFar.dup
  49         newMap[remaining[0]] = true
  50         settingsCombinator(settingsCombinations, newMap, remaining[1..-1])
  51
  52         newMap = mapSoFar.dup
  53         newMap[remaining[0]] = false
  54         settingsCombinator(settingsCombinations, newMap, remaining[1..-1])
  55     end
  56
  57     settingsCombinator(settingsCombinations, {}, (ast.filter(Setting).uniq.collect{|v| v.name} + BACKENDS).uniq)
  58
  59     settingsCombinations
  60 end
  61
  62 #
  63 # forSettings(concreteSettings, ast) {
  64 #     | concreteSettings, lowLevelAST, backend | ... }
  65 #
  66 # Determines if the settings combination is valid, and if so, calls
  67 # the block with the information you need to generate code.
  68 #
  69
  70 def forSettings(concreteSettings, ast)
  71     # Check which architectures this combinator claims to support.
  72     numClaimedBackends = 0
  73     selectedBackend = nil
  74     BACKENDS.each {
  75         | backend |
  76         isSupported = concreteSettings[backend]
  77         raise unless isSupported != nil
  78         numClaimedBackends += if isSupported then 1 else 0 end
  79         if isSupported
  80             selectedBackend = backend
  81         end
  82     }
  83
  84     return if numClaimedBackends > 1
  85
  86     # Resolve the AST down to a low-level form (no macros or conditionals).
  87     lowLevelAST = ast.resolveSettings(concreteSettings)
  88
  89     yield concreteSettings, lowLevelAST, selectedBackend
  90 end
  91
  92 #
  93 # forEachValidSettingsCombination(ast) {
  94 #     | concreteSettings, ast, backend, index | ... }
  95 #
  96 # forEachValidSettingsCombination(ast, settingsCombinations) {
  97 #     | concreteSettings, ast, backend, index | ... }
  98 #
  99 # Executes the given block for each valid settings combination in the
 100 # settings map. The ast passed into the block is resolved
 101 # (ast.resolve) against the settings.
 102 #
 103 # The first form will call computeSettingsCombinations(ast) for you.
 104 #
 105
 106 def forEachValidSettingsCombination(ast, *optionalSettingsCombinations)
 107     raise if optionalSettingsCombinations.size > 1
 108
 109     if optionalSettingsCombinations.empty?
 110         settingsCombinations = computeSettingsCombinations(ast)
 111     else
 112         settingsCombinations = optionalSettingsCombiations[0]
 113     end
 114
 115     settingsCombinations.each_with_index {
 116         | concreteSettings, index |
 117         forSettings(concreteSettings, ast) {
 118             | concreteSettings_, lowLevelAST, backend |
 119             yield concreteSettings, lowLevelAST, backend, index
 120         }
 121     }
 122 end
 123
 124 #
 125 # cppSettingsTest(concreteSettings)
 126 #
 127 # Returns the C++ code used to test if we are in a configuration that
 128 # corresponds to the given concrete settings.
 129 #
 130
 131 def cppSettingsTest(concreteSettings)
 132     "#if " + concreteSettings.to_a.collect{
 133         | pair |
 134         (if pair[1]
 135              ""
 136          else
 137              "!"
 138          end) + "OFFLINE_ASM_" + pair[0]
 139     }.join(" && ")
 140 end
 141
 142 #
 143 # isASTErroneous(ast)
 144 #
 145 # Tests to see if the AST claims that there is an error - i.e. if the
 146 # user's code, after settings resolution, has Error nodes.
 147 #
 148
 149 def isASTErroneous(ast)
 150     not ast.filter(Error).empty?
 151 end
 152
 153 #
 154 # assertConfiguration(concreteSettings)
 155 #
 156 # Emits a check that asserts that we're using the given configuration.
 157 #
 158
 159 def assertConfiguration(concreteSettings)
 160     $output.puts cppSettingsTest(concreteSettings)
 161     $output.puts "#else"
 162     $output.puts "#error \"Configuration mismatch.\""
 163     $output.puts "#endif"
 164 end
 165
 166 #
 167 # emitCodeInConfiguration(concreteSettings, ast, backend) {
 168 #     | concreteSettings, ast, backend | ... }
 169 #
 170 # Emits all relevant guards to see if the configuration holds and
 171 # calls the block if the configuration is not erroneous.
 172 #
 173
 174 def emitCodeInConfiguration(concreteSettings, ast, backend)
 175     $output.puts cppSettingsTest(concreteSettings)
 176
 177     if isASTErroneous(ast)
 178         $output.puts "#error \"Invalid configuration.\""
 179     elsif not WORKING_BACKENDS.include? backend
 180         $output.puts "#error \"This backend is not supported yet.\""
 181     else
 182         yield concreteSettings, ast, backend
 183     end
 184
 185     $output.puts "#endif"
 186 end
 187
 188 #
 189 # emitCodeInAllConfigurations(ast) {
 190 #     | concreteSettings, ast, backend, index | ... }
 191 #
 192 # Emits guard codes for all valid configurations, and calls the block
 193 # for those configurations that are valid and not erroneous.
 194 #
 195
 196 def emitCodeInAllConfigurations(ast)
 197     forEachValidSettingsCombination(ast) {
 198         | concreteSettings, lowLevelAST, backend, index |
 199         $output.puts cppSettingsTest(concreteSettings)
 200         yield concreteSettings, lowLevelAST, backend, index
 201         $output.puts "#endif"
 202     }
 203 end
 204
 205
 206