linker-scripts

问题 I viewed the source code of __libc_init_array from http://newlib.sourcearchive.com/documentation/1.18.0/init_8c-source.html . But I don't quite understand what this function does. I know that these symbols /* These magic symbols are provided by the linker. */ extern void (*__preinit_array_start []) (void) __attribute__((weak)); extern void (*__preinit_array_end []) (void) __attribute__((weak)); extern void (*__init_array_start []) (void) __attribute__((weak)); extern void (*__init_array_end [

问题 I viewed the source code of __libc_init_array from http://newlib.sourcearchive.com/documentation/1.18.0/init_8c-source.html . But I don't quite understand what this function does. I know that these symbols /* These magic symbols are provided by the linker. */ extern void (*__preinit_array_start []) (void) __attribute__((weak)); extern void (*__preinit_array_end []) (void) __attribute__((weak)); extern void (*__init_array_start []) (void) __attribute__((weak)); extern void (*__init_array_end [

问题 I have foo[NUMBYTES] __attribute__((section(".bar"))); Why using this attribute .bar section? Because foo[] provides already some memory space. Is this for easy memory management? 回答1: For bare metal code that run without an operating system, the section attribute , __attribute__((section(".bar"))) , is often used to: Place symbols (data or functions) in a special memory space, such as RAM, FLASH or EEPROMs built into microcontrollers. Place symbols at a special address, e.g. placing the

问题 I have foo[NUMBYTES] __attribute__((section(".bar"))); Why using this attribute .bar section? Because foo[] provides already some memory space. Is this for easy memory management? 回答1: For bare metal code that run without an operating system, the section attribute , __attribute__((section(".bar"))) , is often used to: Place symbols (data or functions) in a special memory space, such as RAM, FLASH or EEPROMs built into microcontrollers. Place symbols at a special address, e.g. placing the

问题 I'm writing a bootable program that is 512 bytes, and I have to stick the 0xAA55 in the last 2 bytes of my 512 byte program image. So I've done that. Now my linker script, should be pretty simple. I was just curious about what this syntax means .foo : { *(.*) } I was given it as an example. There is no .foo section, and before that, I change the program counter to . = 0x1000 //To account for the elf header which I will strip later So after this directive is .foo : { *(.*) } What does this do?

问题 While it could be clear in the context of a resulting binary or ELF file what is a section, many places in documentation (independently of the compiler used) refers them as to Input or Output sections. What are the differences between these? 回答1: The linker consumes object files (and possibly shared libraries) and outputs an executable or shared library. The input object files are composed of named sections - .text , .data , .rodata , .bss , etc. So is the output file. It is a principal part

问题 here's my problem. I have this linker script that links a standard arm7nommu-uClinux kernel: OUTPUT_ARCH(arm) ENTRY(stext) SECTIONS { . = 0x0; .vectors : { *(.resetvector) } . = 0x8000; .init : { /* Init code and data */ _stext = .; __init_begin = .; *(.text.init) __proc_info_begin = .; *(.proc.info) __proc_info_end = .; __arch_info_begin = .; *(.arch.info) __arch_info_end = .; __tagtable_begin = .; *(.taglist) __tagtable_end = .; *(.data.init) . = ALIGN(16); __setup_start = .; *(.setup.init)

问题 What does the ALIGN keyword do in linker scripts? I read many tutorials about linker scripts but I cant understand what really ALIGN do. Can any one explain it simply. Thanks! 回答1: A typical usage is . = ALIGN(8); This means: insert padding bytes until current location becomes aligned on 8-byte boundary. That is: while ((current_location & 7) != 0) *current_location++ = padding_value; 回答2: The ALIGN() instructions tell the linker that section(bss, text) shoul be this much aligned. For a

问题 I'm trying to understand deeper linking process and linker scripts...looking at binutils doc i found a simple linker script implementation that i've improved by adding some commands: OUTPUT_FORMAT("elf32-i386", "elf32-i386", "elf32-i386") OUTPUT_ARCH(i386) ENTRY(mymain) SECTIONS { . = 0x10000; .text : { *(.text) } . = 0x8000000; .data : { *(.data) } .bss : { *(.bss) } } My program is a very simple program: void mymain(void) { int a; a++; } Now i tried to build an executable: gcc -c main.c ld

问题 I've just started learning some ARM programming and I've got stuck in a slightly annoying problem. The toolchain I'm using to compile my sources is Sourcery CodeBench Lite 2013.05-23 (can be found here: https://sourcery.mentor.com/GNUToolchain/release2449) What I would need is to tell GCC or LD or OBJCOPY to put the compiled bytecode of the 'main' function at the beginning of the .text section. Is there any way to achieve this? (maybe through a linker script?) Thank you 回答1: Solved the