Hi there, I'm having some trouble using the linker... I am using V4.1.2 as part of the WinAVR package. The issue I am having is as follows... The package includes a linker script named avr5.x. In that script it has the line "PROVIDE(__heap_start = .)". When I use the linker with --defsym=__heap_start=0x801100, the value generated for __heap_start by the provide is used (0x800124 in my case) rather than the --defsym value. If I comment out the provide line in the linker script the compile fails with an error "Undefined reference to __heap_start" as my code references __heap_start to initialise the heap... Should the --defsym not be providing __heap_start to my code in the absence of the provide() statement? And the --defsym should also override the provide() statement!
I am not 100% sure this is a bug, but cant find any other explanation. Some forum searches reveled some mention of the command line not working in this case. I image this would be a commonly used command line option so should be OK??? Any help would be greatly appreciated... I have attached the linker script and makefiles in case they are of use... Thanks Ashley
############################################################################### # Makefile for the project LinkTuner ############################################################################### ## General Flags PROJECT = LinkTuner MCU = atmega128 TARGET = LinkTuner.elf CC = avr-gcc.exe ## Options common to compile, link and assembly rules COMMON = -mmcu=$(MCU) ## Compile options common for all C compilation units. CFLAGS = $(COMMON) CFLAGS += -Wall -gdwarf-2 -std=gnu99 -DDEBUG -DF_CPU=16000000UL -Os -funsigned-char -funsigned-bitfields -fpack-struct -fshort-enums CFLAGS += -MD -MP -MT $(*F).o -MF dep/$(@F).d ## Assembly specific flags ASMFLAGS = $(COMMON) ASMFLAGS += $(CFLAGS) ASMFLAGS += -x assembler-with-cpp -Wa,-gdwarf2 ## Linker flags LDFLAGS = $(COMMON) LDFLAGS += --defsym=__heap_end=0x806B57 --defsym=__heap_start=0x801100 -minit-stack=0x90FF -Wl,-Map=LinkTuner.map LDFLAGS += -Wl,-section-start=.data=0x800100 LDFLAGS += -Wl,-section-start=.heap=0x801100 LDFLAGS += -Wl,-section-start=.screenbuffer=0x806b58 LDFLAGS += -Wl,-section-start=.noMemory=0x809100 ## Intel Hex file production flags HEX_FLASH_FLAGS = -R .eeprom HEX_EEPROM_FLAGS = -j .eeprom HEX_EEPROM_FLAGS += --set-section-flags=.eeprom="alloc,load" HEX_EEPROM_FLAGS += --change-section-lma .eeprom=0 --no-change-warnings ## Include Directories INCLUDES = -I"D:\Ashley\Projects\LinkTuner\..\MiOS\include" -I"D:\Ashley\Projects\LinkTuner\Include" -I"D:\Ashley\Projects\LinkTuner\..\MiOS" ## Objects that must be built in order to link OBJECTS = imgs.o LCD.o LinkTuner.o graphics.o Heap.o ## Objects explicitly added by the user LINKONLYOBJECTS = ## Build all: $(TARGET) LinkTuner.hex LinkTuner.eep LinkTuner.lss size ## Compile imgs.o: ../Source/imgs.c $(CC) $(INCLUDES) $(CFLAGS) -c $< LCD.o: ../Source/LCD.c $(CC) $(INCLUDES) $(CFLAGS) -c $< LinkTuner.o: ../Source/LinkTuner.c $(CC) $(INCLUDES) $(CFLAGS) -c $< graphics.o: ../Source/graphics.c $(CC) $(INCLUDES) $(CFLAGS) -c $< Heap.o: ../../MiOS/Heap.c $(CC) $(INCLUDES) $(CFLAGS) -c $< ##Link $(TARGET): $(OBJECTS) $(CC) $(LDFLAGS) $(OBJECTS) $(LINKONLYOBJECTS) $(LIBDIRS) $(LIBS) -o $(TARGET) %.hex: $(TARGET) avr-objcopy -O ihex $(HEX_FLASH_FLAGS) $< $@ %.eep: $(TARGET) -avr-objcopy $(HEX_EEPROM_FLAGS) -O ihex $< $@ || exit 0 %.lss: $(TARGET) avr-objdump -h -S $< > $@ size: ${TARGET} @echo @avr-size -C --mcu=${MCU} ${TARGET} ## Clean target .PHONY: clean clean: -rm -rf $(OBJECTS) LinkTuner.elf dep/* LinkTuner.hex LinkTuner.eep LinkTuner.lss LinkTuner.map ## Other dependencies -include $(shell mkdir dep 2>/dev/null) $(wildcard dep/*)
/* Default linker script, for normal executables */ OUTPUT_FORMAT("elf32-avr","elf32-avr","elf32-avr") OUTPUT_ARCH(avr:5) MEMORY { text (rx) : ORIGIN = 0, LENGTH = 128K data (rw!x) : ORIGIN = 0x800060, LENGTH = 0xffa0 eeprom (rw!x) : ORIGIN = 0x810000, LENGTH = 64K } SECTIONS { /* Read-only sections, merged into text segment: */ .hash : { *(.hash) } .dynsym : { *(.dynsym) } .dynstr : { *(.dynstr) } .gnu.version : { *(.gnu.version) } .gnu.version_d : { *(.gnu.version_d) } .gnu.version_r : { *(.gnu.version_r) } .rel.init : { *(.rel.init) } .rela.init : { *(.rela.init) } .rel.text : { *(.rel.text) *(.rel.text.*) *(.rel.gnu.linkonce.t*) } .rela.text : { *(.rela.text) *(.rela.text.*) *(.rela.gnu.linkonce.t*) } .rel.fini : { *(.rel.fini) } .rela.fini : { *(.rela.fini) } .rel.rodata : { *(.rel.rodata) *(.rel.rodata.*) *(.rel.gnu.linkonce.r*) } .rela.rodata : { *(.rela.rodata) *(.rela.rodata.*) *(.rela.gnu.linkonce.r*) } .rel.data : { *(.rel.data) *(.rel.data.*) *(.rel.gnu.linkonce.d*) } .rela.data : { *(.rela.data) *(.rela.data.*) *(.rela.gnu.linkonce.d*) } .rel.ctors : { *(.rel.ctors) } .rela.ctors : { *(.rela.ctors) } .rel.dtors : { *(.rel.dtors) } .rela.dtors : { *(.rela.dtors) } .rel.got : { *(.rel.got) } .rela.got : { *(.rela.got) } .rel.bss : { *(.rel.bss) } .rela.bss : { *(.rela.bss) } .rel.plt : { *(.rel.plt) } .rela.plt : { *(.rela.plt) } /* Internal text space or external memory. */ .text : { *(.vectors) KEEP(*(.vectors)) /* For data that needs to reside in the lower 64k of progmem. */ *(.progmem.gcc*) *(.progmem*) . = ALIGN(2); __trampolines_start = . ; /* The jump trampolines for the 16-bit limited relocs will reside here. */ *(.trampolines) *(.trampolines*) __trampolines_end = . ; /* For future tablejump instruction arrays for 3 byte pc devices. We don't relax jump/call instructions within these sections. */ *(.jumptables) *(.jumptables*) /* For code that needs to reside in the lower 128k progmem. */ *(.lowtext) *(.lowtext*) __ctors_start = . ; *(.ctors) __ctors_end = . ; __dtors_start = . ; *(.dtors) __dtors_end = . ; KEEP(SORT(*)(.ctors)) KEEP(SORT(*)(.dtors)) /* From this point on, we don't bother about wether the insns are below or above the 16 bits boundary. */ *(.init0) /* Start here after reset. */ KEEP (*(.init0)) *(.init1) KEEP (*(.init1)) *(.init2) /* Clear __zero_reg__, set up stack pointer. */ KEEP (*(.init2)) *(.init3) KEEP (*(.init3)) *(.init4) /* Initialize data and BSS. */ KEEP (*(.init4)) *(.init5) KEEP (*(.init5)) *(.init6) /* C++ constructors. */ KEEP (*(.init6)) *(.init7) KEEP (*(.init7)) *(.init8) KEEP (*(.init8)) *(.init9) /* Call main(). */ KEEP (*(.init9)) *(.text) . = ALIGN(2); *(.text.*) . = ALIGN(2); *(.fini9) /* _exit() starts here. */ KEEP (*(.fini9)) *(.fini8) KEEP (*(.fini8)) *(.fini7) KEEP (*(.fini7)) *(.fini6) /* C++ destructors. */ KEEP (*(.fini6)) *(.fini5) KEEP (*(.fini5)) *(.fini4) KEEP (*(.fini4)) *(.fini3) KEEP (*(.fini3)) *(.fini2) KEEP (*(.fini2)) *(.fini1) KEEP (*(.fini1)) *(.fini0) /* Infinite loop after program termination. */ KEEP (*(.fini0)) _etext = . ; } > text .data : AT (ADDR (.text) + SIZEOF (.text)) { PROVIDE (__data_start = .) ; *(.data) *(.data*) *(.rodata) /* We need to include .rodata here if gcc is used */ *(.rodata*) /* with -fdata-sections. */ *(.gnu.linkonce.d*) . = ALIGN(2); _edata = . ; PROVIDE (__data_end = .) ; } > data .bss SIZEOF(.data) + ADDR(.data) : { PROVIDE (__bss_start = .) ; *(.bss) *(.bss*) *(COMMON) PROVIDE (__bss_end = .) ; } > data __data_load_start = LOADADDR(.data); __data_load_end = __data_load_start + SIZEOF(.data); /* Global data not cleared after reset. */ .noinit SIZEOF(.bss) + ADDR(.bss) : { PROVIDE (__noinit_start = .) ; *(.noinit*) PROVIDE (__noinit_end = .) ; _end = . ; PROVIDE (__heap_start = .) ; } > data .eeprom : { *(.eeprom*) __eeprom_end = . ; } > eeprom /* Stabs debugging sections. */ .stab 0 : { *(.stab) } .stabstr 0 : { *(.stabstr) } .stab.excl 0 : { *(.stab.excl) } .stab.exclstr 0 : { *(.stab.exclstr) } .stab.index 0 : { *(.stab.index) } .stab.indexstr 0 : { *(.stab.indexstr) } .comment 0 : { *(.comment) } /* DWARF debug sections. Symbols in the DWARF debugging sections are relative to the beginning of the section so we begin them at 0. */ /* DWARF 1 */ .debug 0 : { *(.debug) } .line 0 : { *(.line) } /* GNU DWARF 1 extensions */ .debug_srcinfo 0 : { *(.debug_srcinfo) } .debug_sfnames 0 : { *(.debug_sfnames) } /* DWARF 1.1 and DWARF 2 */ .debug_aranges 0 : { *(.debug_aranges) } .debug_pubnames 0 : { *(.debug_pubnames) } /* DWARF 2 */ .debug_info 0 : { *(.debug_info) *(.gnu.linkonce.wi.*) } .debug_abbrev 0 : { *(.debug_abbrev) } .debug_line 0 : { *(.debug_line) } .debug_frame 0 : { *(.debug_frame) } .debug_str 0 : { *(.debug_str) } .debug_loc 0 : { *(.debug_loc) } .debug_macinfo 0 : { *(.debug_macinfo) } }
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