Pliant optimizer and code generator

See pliant computing mechanism for a general introduction on meta-programming
The Pliant optimizer and code generator stands in optimize.c which is documented.

If you want to dig in the code generator, just start by running:

pliant debug 0 module /pliant/sample/code_generator.pli

It will display of the sample function (factorial function) at three low level compiling stages:

the initial listing is just before trying to share some complex (non atomic) local variables
the second listing is just before assigning atomic local variables to registers
the last one is just after building the binary executable

All assignments (two local variables are shared or a local variable is assigned to a processor register) are displayed.

This is a sample line extracted from the listing:

2048: cast_uInt_Int c6 a7 <= 768 (uInt Int /pliant/language/type/number/int.pli (internals) 43 1)

It's meaning is:

2048:

The instruction index is 2048. Each instruction in the function is assigned an index that is unic. indices are ordered.

cast_uInt_Int c6 a7

The instruction calls function 'cast_uInt_Int' with two arguments 'c6' and 'a7'
Arguments starting with 'c' are constants.
Arguments starting with 'a' are local variables.
Arguments starting with 'r' are registers: they have to be assigned to a processor register, but we don't know yet which.
Processor registers are displayed using their usual name (EAX, EBX, ...)

<= 768

There is a possible jump to this instruction from instruction with index 768

uInt Int /pliant/language/type/number/int.pli (internals) 43 1

The argument types for function 'cast_uInt_Int' are uInt and Int, and the function is defined in /pliant/language/type/number/int.pli at line 43.