Borutr: Created page with "== Flow of compilation in SDCC == # SDCPP traditional C preprocessing (macro expansion, ...?) # compiling (after reaching the end of the source file, the initializers for..."

2012-12-04T10:41:04Z

Created page with "== Flow of compilation in SDCC == # SDCPP traditional C preprocessing (macro expansion, ...?) # compiling (after reaching the end of the source file, the initializers for..."

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== Flow of compilation in SDCC ==

# [[SDCPP traditional C preprocessing]] (macro expansion, ...?)
# compiling (after reaching the end of the source file, the initializers for any non-const global or static variables also go through these same steps)
## [[parsing]]: preprocessed code -> AST
## AST -> icode conversion
## target independent icode optimisation
## target dependent icode optimisation and register allocation
## assembly code generation: icode -> target-specific asm
## peephole optimisation
# assembling
# linking

----

== some details on the "top level" ==
main = SDCC.EXE

=== source ===
* sdcc/sdcc/src/SDCCmain.c

=== what does it do ===
See the tree on top for links to pages with info on each step:

* based on command line establishes which port is to be used
* initialises this port
* parses command line options
* passes the relevant options to the port
* calls the preprocessor SDCPP.EXE
* feeds the output into the parser "character by character"
** via a pipe - preprocessing is completely separate from other parts, there are no common data - it could be run standalone, output into a temporary file and feed that into the lexer part of compiler)
* parser calls the subsequent steps - function by function
** once the parser recognizes that a function is complete, createFunction() (in src/SDCCast.c) is called, which has the AST annotated (probably via decorateType()), has it turned it into iCode (iCodeFromAst() calling ast2iCode()), and lets the backend emit appropriate code (via eBBlockFromiCode() in port->assignRegisters, which maps to, e.g.src/mcs51/ralloc.c, mcs51_assignRegisters())
** eBBlockFromiCode(): cseAllBlocks(), killDeadCode(), loopOptimizations(), all src/SDCCopt.c
* calls the assembler
* calls the linker

Run SDCC with both "-V --verbose" to see some of these steps.

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Borutr: Created page with "== Flow of compilation in SDCC == # SDCPP traditional C preprocessing (macro expansion, ...?) # compiling (after reaching the end of the source file, the initializers for..."