4.4.4 xc32-g++ (32-bit C++ Compiler)

A subset of command-line options may be specified in MPLAB X IDE. Select a category and set up C++ options.

See also 4.4.7 Options Page Features.

Table 4-7. XC32-G++ C++ Specific Category
OptionDescriptionCommand Line
Generate run time type descriptor informationEnable generation of information about every class with virtual functions for use by the C++ runtime type identification features (dynamic_cast and typeid). If you don't use those parts of the language, you can save some space by disabling this option. Note that exception handling uses the same information, but it will generate it as needed. The dynamic_cast operator can still be used for casts that do not require runtime type information, that is, casts to void * or to unambiguous base classes.-frtti
Enable C++ exception handlingEnable exception handling. Generates extra code needed to propagate exceptions.-fexceptions
Check that the pointer returned by operator 'new' is non-nullCheck that the pointer returned by operator new is non-null before attempting to modify the storage allocated.-fcheck-new
Generate code to check for violation of exception specificationGenerate code to check for violation of exception specifications at runtime. Using this option may increase code size in production builds.-fenforce-eh-specs
Table 4-8. XC32-G++ General Category
OptionDescriptionCommand Line
Have symbols in production buildBuild for debugging in a production build image.-g
Enable App IOSupport the APPIN/APPOUT debugging feature with REAL ICE.-mappio-debug
Isolate each function in a sectionPlace each function into its own section in the output file if the target supports arbitrary sections. The name of the function or the name of the data item determines the section's name in the output file. This option is useful when combined with the linker’s --gc-sections option to remove unreferenced functions.-ffunction-sections
Place data into its own sectionPlace each data item into its own section in the output file if the target supports arbitrary sections. The name of the function or the name of the data item determines the section's name in the output file. This option is useful when combined with the linker’s --gc-sections option to remove unreferenced variables.-fdata-sections
Enable toplevel reorderingAllows the compiler to reorder top-level functions, variables, and asm statements, in which case, they might not be output in the same order that they appear in the input file.-ftoplevel-reorder
Use indirect callsEnable full-range calls.-mlong-calls
Generate MIPS16 16-bit codeBy default, generate code for the MIPS16 instruction set, reducing code size.-mips16
Generate microMIPS compressed codeGenerate code using the microMIPS instructions. This feature is available only in the PRO edition.-m[no-]micromips
Exclude floating-point libraryExclude support for floating-point operations reducing code size for applications that do not require floating-point support.-mno-float
Table 4-9. XC32-G++ Optimization Category
OptionDescriptionCommand Line
Optimization LevelSelect an optimization level. Your compiler edition may support only some optimizations. Equivalent to -On option, where n is an option below:

0 - Do not optimize. The compiler’s goal is to reduce the cost of compilation and to make debugging produce the expected results.

1 - Optimize. Optimizing compilation takes somewhat longer and a lot more host memory for a large function. The compiler tries to reduce code size and execution time.

2 - Optimize even more. The compiler performs nearly all supported optimizations that do not involve a space-speed trade-off.

3 - Optimize yet more favoring speed (superset of O2).

s - Optimize yet more favoring size (superset of O2).

-O0 -O1 -O2 -O3 -Os
Unroll loopsCheck to perform the optimization of loop unrolling. This is only done for loops whose number of iterations can be determined at compile time or run time.

Uncheck to not unroll loops.

-funroll-loops
Omit frame pointerCheck to not keep the Frame Pointer in a register for functions that don’t need one.

Uncheck to keep the Frame Pointer.

-fomit-frame-pointer
Pre-optimization instruction schedulingDefault for optimization level:

- Disable

- Enable

-f[no-]schedule-insns

Post-optimization instruction schedulingDefault for optimization level:

- Disable

- Enable

-f[no-]schedule-insns2

Table 4-10. XC32-G++ Preprocessing and Messages Category
OptionDescriptionCommand Line
Preprocessor macrosProject-specific preprocessor macro defines passed via the compiler’s –D option.

-Dmacro[=defn]

Include directoriesSearch these directories for project-specific include files.

-I path

Make warnings into errors

Check to halt compilation based on warnings as well as errors.

Uncheck to halt compilation based on errors only.

-Werror
Additional warnings

Check to enable all warnings.

Uncheck to disable warnings.

-Wall
Enable address-attribute warning-Waddress-attribute-use
strict-ansiIssue all the warnings demanded by strict ISO C and ISO C++; reject all programs that use forbidden extensions, and some other programs that do not follow ISO C and ISO C++.-pedantic
Use CCI syntaxEnable support for the CCI syntax (25 Common C Interface).-mcci
Use IAR syntaxEnable support for syntax used by other toolchain vendors.-mext=IAR