Support for SDIV and MLS ARM instructions, and implement DoModI using them

build/common.gypi

 # Copyright 2012 the V8 project authors. All rights reserved.
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 #       notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 #       copyright notice, this list of conditions and the following
 #       disclaimer in the documentation and/or other materials provided
@@ skipping 25 matching lines @@
     'v8_target_arch%': '<(target_arch)',
 
     # Setting 'v8_can_use_unaligned_accesses' to 'true' will allow the code
     # generated by V8 to do unaligned memory access, and setting it to 'false'
     # will ensure that the generated code will always do aligned memory
     # accesses. The default value of 'default' will try to determine the correct
     # setting. Note that for Intel architectures (ia32 and x64) unaligned memory
     # access is allowed for all CPUs.
     'v8_can_use_unaligned_accesses%': 'default',
 
+    # Setting 'v8_can_use_integer_division' to 'true' will allow the code
+    # generated by V8 to utilize hardware integer division instruction
+    # Setting it to 'false' will not use hardware integer division instruction
+    'v8_can_use_integer_division%': 'true',

[danno, 2012/09/27 15:28:09]

I think this flag is mis-named. can_use_sdiv_instructions or something similar
is better, since flags expressing similar functionality (VFP) clearly reference
something that is ARM-specific.

also, I we can't land this in the current form as a compile-time flag, since
there is only one binary that gets distributed on ARM

+
     # Setting 'v8_can_use_vfp2_instructions' to 'true' will enable use of ARM VFP
     # instructions in the V8 generated code. VFP instructions will be enabled
     # both for the snapshot and for the ARM target. Leaving the default value
     # of 'false' will avoid VFP instructions in the snapshot and use CPU feature
     # probing when running on the target.
     'v8_can_use_vfp2_instructions%': 'false',
     'v8_can_use_vfp3_instructions%': 'false',
 
     # Similar to vfp but on MIPS.
     'v8_can_use_fpu_instructions%': 'true',
@@ skipping 76 matching lines @@
           [ 'v8_can_use_unaligned_accesses=="true"', {
             'defines': [
               'CAN_USE_UNALIGNED_ACCESSES=1',
             ],
           }],
           [ 'v8_can_use_unaligned_accesses=="false"', {
             'defines': [
               'CAN_USE_UNALIGNED_ACCESSES=0',
             ],
           }],
+          [ 'v8_can_use_integer_division=="true"', {
+            'defines': [
+              'CAN_USE_INTEGER_DIVISION=1',
+            ],
+          }],
+          [ 'v8_can_use_integer_division=="false"', {
+            'defines': [
+              'CAN_USE_INTEGER_DIVISION=0',
+            ],
+          }],
           [ 'v8_can_use_vfp2_instructions=="true"', {
             'defines': [
               'CAN_USE_VFP2_INSTRUCTIONS',
             ],
           }],
           [ 'v8_can_use_vfp3_instructions=="true"', {
             'defines': [
               'CAN_USE_VFP3_INSTRUCTIONS',
             ],
           }],
@@ skipping 269 matching lines @@
                 'OptimizeReferences': '2',
                 'EnableCOMDATFolding': '2',
               },
             },
           }],  # OS=="win"
         ],  # conditions
       },  # Release
     },  # configurations
   },  # target_defaults
 }