Why are some relocations .text + addend instead of symbol's name + addend?

Why are some relocation entries in an ELF file symbol name + addend while others are section + addend? I am looking to clear up some confusion and gain a deeper understanding of ELFs. Below is my investigation.

I have a very simple C file, test.c:

#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>

static void func1(void)
{
    fprintf(stdout, "Inside func1\n");
}

// ... a couple other simple *static* functions

int main (void)
{
    func1();

    // ... call some other functions

    exit(EXIT_SUCCESS);
}

I then compile this into an object file with:

clang -O0 -Wall -g -c test.c -o test.o

If look at the relocations with readelf -r test.o I see the entries that refer to my static functions as follows (this one is picked from the .rela.debug_info section):

Offset            Info              Type         Symbol's Value    Symbol's Name + Addend
...
000000000000006f  0000000400000001  R_X86_64_64  0000000000000000 .text + b0
...

Why are these functions referred to as section + addend rather than symbol name + addend? I see entries for the functions in the .symtab using readelf -s test.o:

Num: Value            Size Type Bind  Vis     Ndx Name
  ...
  2: 00000000000000b0 31   FUNC LOCAL DEFAULT 2   func1
  ...

Additionally, when I disassemble the object file (via objdump -d), I see that the functions are there and weren't optimized into main or anything.

If I don't make the functions static and then look at the relocations, I see the same as before when the type is R_X86_64_64, but I also see entries that use the symbol name plus an addend with type R_X86_64_PC32. So for example in .rela.text:

Offset            Info              Type           Symbol's Value    Symbol's Name + Addend
...
00000000000000fe  0000001200000002  R_X86_64_PC32  0000000000000000  func1 + 1c
...

Please let me know if more examples/readelf output would be helpful. Thank you for taking the time to read this.

Solution

Why are these functions referred to as section + addend rather than symbol name + addend?

The function names for static functions are not guaranteed to be present at link time. You could remove them with e.g. objcopy --strip-unneeded or objcopy --strip-symbol, and the result will still link.

I see entries for the functions in the .symtab using readelf -s test.o

I believe the only reason they are kept is to help debugging, and they are not used by the linker at all. But I have not verified this by looking at linker source, and so did not answer this related question.