Is there a way to force the old behavior? Yes. You can use this option -Wl,–disable-new-dtags to tell the new linker to use the old behavior, i.e. RPATH. Is it possible to tell the old version of linker to produce the new output (i.e. RUNPATH instead of RPATH)? Yes. Use -Wl,–enable-new-dtags to tell the old … Read more
One solution that I most commonly use is to actually use the GNU linker (ld) to build the IDT and GDT for me. This answer isn’t a primer on writing GNU linker scripts, but it does make use of the BYTE, SHORT, and LONG linker script directives to build the IDT, the GDT, the IDT … Read more
Shorter answer: Accessing the “value” of a linker script variable is NOT undefined behavior, and is fine to do, so long as you want the actual data stored at that location in memory and not the address of that memory or the “value” of a linkerscript variable which happens to be seen by C code … Read more
As far as I can tell, GNU binutils does not support the Mach-O format. None of the documentation mentions it, and some Googling turns up some recent messages indicating that it is not supported. Now, you mention the Contiki OS, which looks to me like an embedded operating system. Are you needing to compile to … Read more
As far as I can tell, GNU binutils does not support the Mach-O format. None of the documentation mentions it, and some Googling turns up some recent messages indicating that it is not supported. Now, you mention the Contiki OS, which looks to me like an embedded operating system. Are you needing to compile to … Read more
This optimization has since been implemented in GCC. It can be enabled with the -fno-plt option and the noplt function attribute: Do not use the PLT for external function calls in position-independent code. Instead, load the callee address at call sites from the GOT and branch to it. This leads to more efficient code by … Read more
This is a byproduct of the way that .a libraries work – they’re simply a collection of .o files. What happens at compile link time is that the first reference to the name gets resolved to the weak reference and the strong name never gets a look in. You can test this yourself by actually … Read more
The following example works for me: $ dd if=/dev/urandom of=binblob bs=1024k count=1 $ objcopy -I binary -O elf32-little binblob binblob.o $ file binblob.o binblob.o: ELF 32-bit LSB relocatable, no machine, version 1 (SYSV), not stripped $ nm -S -t d binblob.o 0000000001048576 D _binary_binblob_end 0000000001048576 A _binary_binblob_size 0000000000000000 D _binary_binblob_start I.e. no need to specify … Read more
global directive is NASM specific. It is for exporting symbols in your code to where it points in the object code generated. Here you mark _start symbol global so its name is added in the object code (a.o). The linker (ld) can read that symbol in the object code and its value so it knows … Read more
Afaik LD keeps the symbols in the section even if symbols are not referenced. (–gc-sections). Usually used for sections that have some special meaning in the binary startup process, more or less to mark the roots of the dependency tree. (For Sabuncu below) Dependency tree: If you eliminate unused code, you analyze the code and … Read more