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     nonBackendSettings = ast.filter(Setting).uniq.collect{ |v| v.name }
  58     nonBackendSettings.delete_if {
  59         | setting |
  60         isBackend? setting
  61     }
  62
  63     allBackendsFalse = {}
  64     BACKENDS.each {
  65         | backend |
  66         allBackendsFalse[backend] = false
  67     }
  68
  69     # This will create entries for invalid backends. That's fine. It's necessary
  70     # because it ensures that generate_offsets_extractor (which knows about valid
  71     # backends) has settings indices that are compatible with what asm will see
  72     # (asm doesn't know about valid backends).
  73     BACKENDS.each {
  74         | backend |
  75         map = allBackendsFalse.clone
  76         map[backend] = true
  77         settingsCombinator(settingsCombinations, map, nonBackendSettings)
  78     }
  79
  80     settingsCombinations
  81 end
  82
  83 #
  84 # forSettings(concreteSettings, ast) {
  85 #     | concreteSettings, lowLevelAST, backend | ... }
  86 #
  87 # Determines if the settings combination is valid, and if so, calls
  88 # the block with the information you need to generate code.
  89 #
  90
  91 def forSettings(concreteSettings, ast)
  92     # Check which architectures this combinator claims to support.
  93     numClaimedBackends = 0
  94     selectedBackend = nil
  95     BACKENDS.each {
  96         | backend |
  97         if concreteSettings[backend]
  98             raise if selectedBackend
  99             selectedBackend = backend
 100         end
 101     }
 102
 103     return unless isValidBackend? selectedBackend
 104
 105     # Resolve the AST down to a low-level form (no macros or conditionals).
 106     lowLevelAST = ast.resolveSettings(concreteSettings)
 107
 108     yield concreteSettings, lowLevelAST, selectedBackend
 109 end
 110
 111 #
 112 # forEachValidSettingsCombination(ast) {
 113 #     | concreteSettings, ast, backend, index | ... }
 114 #
 115 # forEachValidSettingsCombination(ast, settingsCombinations) {
 116 #     | concreteSettings, ast, backend, index | ... }
 117 #
 118 # Executes the given block for each valid settings combination in the
 119 # settings map. The ast passed into the block is resolved
 120 # (ast.resolve) against the settings.
 121 #
 122 # The first form will call computeSettingsCombinations(ast) for you.
 123 #
 124
 125 def forEachValidSettingsCombination(ast, *optionalSettingsCombinations)
 126     raise if optionalSettingsCombinations.size > 1
 127
 128     if optionalSettingsCombinations.empty?
 129         settingsCombinations = computeSettingsCombinations(ast)
 130     else
 131         settingsCombinations = optionalSettingsCombiations[0]
 132     end
 133
 134     settingsCombinations.each_with_index {
 135         | concreteSettings, index |
 136         forSettings(concreteSettings, ast) {
 137             | concreteSettings_, lowLevelAST, backend |
 138             yield concreteSettings, lowLevelAST, backend, index
 139         }
 140     }
 141 end
 142
 143 #
 144 # cppSettingsTest(concreteSettings)
 145 #
 146 # Returns the C++ code used to test if we are in a configuration that
 147 # corresponds to the given concrete settings.
 148 #
 149
 150 def cppSettingsTest(concreteSettings)
 151     "#if " + concreteSettings.to_a.collect{
 152         | pair |
 153         (if pair[1]
 154              ""
 155          else
 156              "!"
 157          end) + "OFFLINE_ASM_" + pair[0]
 158     }.join(" && ")
 159 end
 160
 161 #
 162 # isASTErroneous(ast)
 163 #
 164 # Tests to see if the AST claims that there is an error - i.e. if the
 165 # user's code, after settings resolution, has Error nodes.
 166 #
 167
 168 def isASTErroneous(ast)
 169     not ast.filter(Error).empty?
 170 end
 171
 172 #
 173 # assertConfiguration(concreteSettings)
 174 #
 175 # Emits a check that asserts that we're using the given configuration.
 176 #
 177
 178 def assertConfiguration(concreteSettings)
 179     $output.puts cppSettingsTest(concreteSettings)
 180     $output.puts "#else"
 181     $output.puts "#error \"Configuration mismatch.\""
 182     $output.puts "#endif"
 183 end
 184
 185 #
 186 # emitCodeInConfiguration(concreteSettings, ast, backend) {
 187 #     | concreteSettings, ast, backend | ... }
 188 #
 189 # Emits all relevant guards to see if the configuration holds and
 190 # calls the block if the configuration is not erroneous.
 191 #
 192
 193 def emitCodeInConfiguration(concreteSettings, ast, backend)
 194     Label.resetReferenced
 195
 196     if !$emitWinAsm
 197         $output.puts cppSettingsTest(concreteSettings)
 198     else
 199         if backend == "X86_WIN"
 200             $output.puts ".MODEL FLAT, C"
 201         end
 202         $output.puts "INCLUDE #{File.basename($output.path)}.sym"
 203         $output.puts "_TEXT SEGMENT"
 204     end
 205
 206     if isASTErroneous(ast)
 207         $output.puts "#error \"Invalid configuration.\""
 208     elsif not WORKING_BACKENDS.include? backend
 209         $output.puts "#error \"This backend is not supported yet.\""
 210     else
 211         yield concreteSettings, ast, backend
 212     end
 213
 214     if !$emitWinAsm
 215         $output.puts "#endif"
 216     else
 217         $output.puts "_TEXT ENDS"
 218         $output.puts "END"
 219
 220         # Write symbols needed by MASM
 221         File.open("#{File.basename($output.path)}.sym", "w") {
 222             | outp |
 223             Label.forReferencedExtern {
 224                 | name |
 225                 outp.puts "EXTERN #{name[1..-1]} : near"
 226             }
 227         }
 228     end
 229 end
 230
 231 #
 232 # emitCodeInAllConfigurations(ast) {
 233 #     | concreteSettings, ast, backend, index | ... }
 234 #
 235 # Emits guard codes for all valid configurations, and calls the block
 236 # for those configurations that are valid and not erroneous.
 237 #
 238
 239 def emitCodeInAllConfigurations(ast)
 240     forEachValidSettingsCombination(ast) {
 241         | concreteSettings, lowLevelAST, backend, index |
 242         $output.puts cppSettingsTest(concreteSettings)
 243         yield concreteSettings, lowLevelAST, backend, index
 244         $output.puts "#endif"
 245     }
 246 end
 247
 248
 249