Cleaned up pre/post inc/dec in bytecode
https://bugs.webkit.org/show_bug.cgi?id=115222

Reviewed by Filip Pizlo.

Source/JavaScriptCore: 

A few related changes here:

(*) Removed post_inc and post_dec. The two-result form was awkward to
reason about. Being explicit about the intermediate mov and to_number
reduces DFG overhead, removes some fragile ASSERTs from the DFG, and
fixes a const bug. Plus, we get to blow away 262 lines of code.

(*) Renamed pre_inc and pre_dec to inc and dec, since there's only one
version now.

(*) Renamed to_jsnumber to to_number, to match the ECMA name.

(*) Tightened up the codegen and runtime support for to_number.


* JavaScriptCore.order: Order!

* bytecode/CodeBlock.cpp:
(JSC::CodeBlock::dumpBytecode):
* bytecode/Opcode.h:
(JSC::padOpcodeName):
* bytecompiler/BytecodeGenerator.cpp:
(JSC::BytecodeGenerator::emitInc):
(JSC::BytecodeGenerator::emitDec):
* bytecompiler/BytecodeGenerator.h:
(JSC::BytecodeGenerator::emitToNumber):
(BytecodeGenerator): Removed post_inc and post_dec.

* bytecompiler/NodesCodegen.cpp:
(JSC::emitPreIncOrDec): Updated for rename.

(JSC::emitPostIncOrDec): Issue an explicit mov and to_number when needed.
These are rare, and they boil away in the DFG.

(JSC::PostfixNode::emitResolve):
(JSC::PrefixNode::emitResolve): For const, use an explicit mov instead
of any special forms. This fixes a bug where we would do string
add/subtract instead of number.

* dfg/DFGByteCodeParser.cpp:
(JSC::DFG::ByteCodeParser::parseBlock):
* dfg/DFGCapabilities.h:
(JSC::DFG::canCompileOpcode):
* jit/JIT.cpp:
(JSC::JIT::privateCompileMainPass):
(JSC::JIT::privateCompileSlowCases):
* jit/JIT.h:
* jit/JITArithmetic.cpp:
(JSC::JIT::emit_op_inc):
(JSC::JIT::emitSlow_op_inc):
(JSC::JIT::emit_op_dec):
(JSC::JIT::emitSlow_op_dec):
* jit/JITArithmetic32_64.cpp:
(JSC::JIT::emit_op_inc):
(JSC::JIT::emitSlow_op_inc):
(JSC::JIT::emit_op_dec):
(JSC::JIT::emitSlow_op_dec): Removed post_inc/dec, and updated for renames.

* jit/JITOpcodes.cpp:
(JSC::JIT::emit_op_to_number):
(JSC::JIT::emitSlow_op_to_number): Removed a test for number cells. There's
no such thing!

* jit/JITOpcodes32_64.cpp:
(JSC::JIT::emit_op_to_number): Use LowestTag to avoid making assumptions
about the lowest valued tag.

(JSC::JIT::emitSlow_op_to_number): Updated for renames.

* jit/JITStubs.cpp:
(JSC::DEFINE_STUB_FUNCTION):
* jit/JITStubs.h:
* llint/LLIntSlowPaths.cpp:
(JSC::LLInt::LLINT_SLOW_PATH_DECL):
* llint/LLIntSlowPaths.h:
* llint/LowLevelInterpreter32_64.asm:
* llint/LowLevelInterpreter64.asm:
* parser/NodeConstructors.h:
(JSC::UnaryPlusNode::UnaryPlusNode): Removed post_inc/dec, and updated for renames.

* runtime/Operations.cpp:
(JSC::jsIsObjectType): Removed a test for number cells. There's
no such thing!

LayoutTests: 

* fast/js/const-expected.txt:
* fast/js/resources/const.js: Added tests for some const cases we used
to get wrong.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@149247 268f45cc-cd09-0410-ab3c-d52691b4dbfc