Мой сценарий использования выглядит следующим образом:

I am using a typical SDK that comes with Makefile based projects I belive the linker is patched gcc. gcc --version gives me 4.3.4 SDK defines the linker script (lets call it Linker.ld) Linker.ld includes LinkerMemMap.cfg, which defines the absolute addresses for various sections in the linked ELF image SDK provides application templates based on Makefiles (GNU Make 3.81) and make itself In the SDK provided Makefile template, when gcc is invoked the Linker.ld is provided with -T command line option, as follows:

gcc $(OBJS) -l$(Lib1) -l$(Lib2) -nostdlib -lgcc -L$(library_path) -g -msmall-mode -mconst-switch-tables -mas-mode -mno-initc -Wl,--start-group,--end-group,-T,$(PATH_TO_Linker.ld),--gc-sections -o$(OUTPUT).elf

Мое требование заключается в следующем:

I would like to use the sections as defined in Linker.ld and use the memory map as per LinkerMemMap.cfg however tweak a particular symbol(lets call it SYMBOL_RAM_START) defined in LinkerMemMap.cfg

Что работает:

I have tried in the makefile, prior to linking the final ELF image, copy the LinkerMemMap.cfg (which is included by Linker.ld) to the build directory and patch it to redefine SYMBOL_RAM_START. This does work as the linker searches for the linker scripts and the files included by the linker scripts in the current folder first.

Что не так:

Unfortunately our stakeholders think the above method is too risky and complex to understand. I would like to override the symbol value on the linker command line with something like below:

gcc $(OBJS) -l$(Lib1) -l$(Lib2) -nostdlib -lgcc -L$(library_path) -g -msmall-mode -mconst-switch-tables -mas-mode -mno-initc -Wl,--start-group,--end-group,-T,$(PATH_TO_Linker.ld),--gc-sections,--defsym=SYMBOL_RAM_START=$(VALUE_TO_OVERRIDE) -o$(OUTPUT).elf

gcc $(OBJS) -l$(Lib1) -l$(Lib2) -nostdlib -lgcc -L$(library_path) -g -msmall-mode -mconst-switch-tables -mas-mode -mno-initc -Wl,--start-group,--end-group,-T,$(PATH_TO_Linker.ld),--gc-sections --defsym=SYMBOL_RAM_START=$(VALUE_TO_OVERRIDE) -o$(OUTPUT).elf

gcc $(OBJS) -l$(Lib1) -l$(Lib2) --defsym=SYMBOL_RAM_START=$(VALUE_TO_OVERRIDE) -nostdlib -lgcc -L$(library_path) -g -msmall-mode -mconst-switch-tables -mas-mode -mno-initc -Wl,--start-group,--end-group,-T,$(PATH_TO_Linker.ld),--gc-sections -o$(OUTPUT).elf

Кажется, что ни один из них не влияет на связанное изображение, созданное компоновщиком.

Can --defsym override the symbols defined by linkerscript specified using -T? Could any of you please see what am I doing wrong here?