[Harmony Wiki] Update of "Jitrino OPT/layout" by Mikhail Fursov

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The following page has been changed by Mikhail Fursov:
http://wiki.apache.org/harmony/Jitrino_OPT/layout

New page:
The 'layout' is LIR transformation used to assign relative positions for basic blocks in memory.
Three different layout algorithms are supported today:

1) Topological (reverse-postorder) layout of basic blocks
2) Top-down layout algorithm
3) Bottom-up layout algorithm

To read more about top-down and bottom-up algorithm details check "Profile guided code positioning" paper by Hansen & Pettis.

Command line line options:

jit.arg.codegen.layout.type=topological - enables topological layout

jit.arg.codegen.layout.type=topdown - enables top-down layout

jit.arg.codegen.layout.type=bottomup - enables bottom-up layout

jit.arg.codegen.layout.type=mixed - enables top-down layout for methods without loops and bottom-up for methods with loops


Source files:

src/codegenerator/ia32/Ia32CodeLayout.*

src/codegenerator/ia32/Ia32CodeLayoutTopDown.*

src/codegenerator/ia32/Ia32CodeLayoutBottomUp.*