6.5 KiB
DMBS - Dean's Makefile Build System
Module: GCC
The GCC module provides build targets to compile a user application, using a
variant of GCC for a specific target architecture (such as avr-gcc).
Importing This Module into a Makefile:
To use this module in your application makefile, add the following code to your makefile:
include $(DMBS_PATH)/gcc.mk
Prerequisites:
This module requires the GCC compiler to be installed and available in the
system's PATH variable for the desired target architecture.
Build Targets:
The following targets are supported by this module:
| size | Show the compiled binary size for the various memory segments. |
| symbol-sizes | Show the size of each symbol in the compiled binary (useful to find large functions to optimize further). |
| all | Build application and generate all binary (BIN, ELF, HEX) and auxiliary (LSS, MAP, SYM, etc.) output files. |
| lib | Generate a static `.a` library from the application code, containing the flash region's data. |
| elf | Generate an ELF debug file from the application code, containing all region's data. |
| bin | Generate a flat BIN binary file from the application code, containing the flash region's data. |
| hex | Generate a pair of Intel HEX files from the application code, containing the flash region's data (HEX) and EEPROM data (EEP). |
| lss | Generate a LSS listing file showing the disassembly of the compiled application. |
| clean | Remove all generated project intermediary and binary output files. |
| mostlyclean | Remove all generated project intermediary output files, but preserve the binary output files. |
Mandatory Variables:
The following variables must be defined (with a NAME = VALUE syntax, one
variable per line) in the user makefile to be able to use this module:
| MCU | Name of the Atmel processor model (e.g. `at90usb1287`). |
| TARGET | Name of the application output file prefix (e.g. `TestApplication`). |
| ARCH | Target device architecture (e.g. `AVR8`). |
| SRC | List of all project source files (C, C++, ASM). |
Optional Variables:
The following variables may be defined (with a NAME = VALUE syntax, one
variable per line) in the user makefile. If not specified, a default value will
be assumed.
| COMPILER_PATH | Path to the compiler to use, in case a specific compiler should be substituted for the one in the system's `PATH` variable. Default is blank (use `PATH` provided compiler). |
| OPTIMIZATION | Optimization level to use when compiling C and C++ source files. Default is `s` (optimize for smallest size). |
| C_STANDARD | C language standard used when compiling C language source files. Default is `gnu99` (C99 standard with GNU extensions)./td> |
| CPP_STANDARD | C++ language standard used when compiling C++ language source files. Default is `gnu++98` (C++98 standard with GNU extensions)./td> |
| F_CPU | Processor core clock frequency, in Hz. This is used by some architectures for functions such as software spin-loop delays. Default is blank (no value defined). |
| C_FLAGS | Common GCC flags passed to the compiler for C language (C) input files. Default is blank (no additional flags). |
| CPP_FLAGS | Common GCC flags passed to the compiler for C++ language (CPP) input files. Default is blank (no additional flags). |
| ASM_FLAGS | Common GCC flags passed to the assembler for assembly language (S) input files. Default is blank (no additional flags). |
| CC_FLAGS | Common GCC flags passed to the compiler for all source file types. Default is blank (no additional flags). |
| LD_FLAGS | Extra flags to pass to the GNU linker when linking the compiled object files into the resulting binary. Default is blank (no additional flags). |
| LINKER_RELAXATIONS | Boolean, if `Y` linker relaxations will be enabled to slightly reduce the resulting binary's size. Default is `Y`. |
| JUMP_TABLES | Boolean, if `Y` jump tables will be enabled to slightly reduce the resulting binary's size - note that this can cause incorrect jumps if the binary is relocated after compilation, such as for a bootloader. Default is `N`. |
| OBJDIR | Directory to store the intermediate object files, as they are generated from the source files. Default is `obj`. |
| OBJECT_FILES | List of additional `.o` object files to link into the final binary. Default is blank (no additional objects). |
| DEBUG_FORMAT | Debug ELF file format to generate. Default is `dwarf-2`. |
| DEBUG_LEVEL | Level of the debugging information to generate in the compiled object files. Debug is 2 (medium level debugging information). |
Provided Variables:
The following variables may be referenced in a user makefile (via $(NAME)
syntax) if desired, as they are provided by this module.
| N/A | This module provides no variables. |
Provided Macros:
The following macros may be referenced in a user makefile (via
$(call NAME, ARG1, ARG2, ...) syntax) if desired, as they are provided by
this module.
| N/A | This module provides no macros. |
Module Changelog:
The changes to this module since its initial release are listed below, as of the DMBS version where the change was made.
20170426
Added JUMP_TABLES optional variable.
20160403
Initial release.