Option Recommendations

Depending on the compiled source code files, each Compiler option has advantages or disadvantages. We recommend the following:

• When using the HIWARE Object-file Format and the -Cc: Allocate Const Objects into ROM compiler option, specify ROM_VAR in the Linker parameter file.
• -Wpd: Error for Implicit Parameter Declaration
• -Or: Register Optimization whenever available or possible

The default configuration enables most options in the Compiler. If the default options cause problems in your code (for example, they make the code hard to debug), disable the options (these options usually have the -On prefix). Candidates for such options are peephole options.

Some options produce more code for some functions than for others (for example, -Oi: Inlining or -Cu: Loop Unrolling). On the other hand, inlining functions, while producing more code, also make it execute faster because there's not overhead in performing a function call. Vary your option choices to find the best result for each function.

To get the best results for each function, compile each module with the -OdocF option (refer -OdocF: Dynamic Option Configuration for Functions). An example of this option is -OdocF="-Or".

For compilers with the ICG optimization engine, the following option combination provides the best results:

  -Ona -OdocF="-Onca|-One|-Or"