Force GCC to keep section when using link time optimization - gcc

Question

I have a C struct that is compiled by GCC into a special section and placed at the beginning of an output binary via a linker script. It contains file metadata, including a magic value at the beginning.
Here's a simplified example using just a string as the struct.
const char __magic_value[9] __attribute__((section(".the_header"))) = "MAGICVAL";
GCC places this value into its own section, as we can see with readelf -S:
There are 10 section headers, starting at offset 0x190:
Section Headers:
[Nr] Name Type Addr Off Size ES Flg Lk Inf Al
[ 0] NULL 00000000 000000 000000 00 0 0 0
[ 1] .text PROGBITS 00000000 000034 000000 00 AX 0 0 2
[ 2] .data PROGBITS 00000000 000034 000000 00 WA 0 0 1
[ 3] .bss NOBITS 00000000 000034 000000 00 WA 0 0 1
[ 4] .the_header PROGBITS 00000000 000034 000009 00 A 0 0 1
[ 5] .comment PROGBITS 00000000 00003d 00001e 01 MS 0 0 1
[ 6] .ARM.attributes ARM_ATTRIBUTES 00000000 00005b 000033 00 0 0 1
[ 7] .shstrtab STRTAB 00000000 00008e 000051 00 0 0 1
[ 8] .symtab SYMTAB 00000000 0000e0 000090 10 9 8 4
[ 9] .strtab STRTAB 00000000 000170 00001e 00 0 0 1
Key to Flags:
W (write), A (alloc), X (execute), M (merge), S (strings)
I (info), L (link order), G (group), T (TLS), E (exclude), x (unknown)
O (extra OS processing required) o (OS specific), p (processor specific)
(Note section #4.)
Now, if I specify -flto to the GCC invocation, this section is no longer emitted!
There are 19 section headers, starting at offset 0x730:
Section Headers:
[Nr] Name Type Addr Off Size ES Flg Lk Inf Al
[ 0] NULL 00000000 000000 000000 00 0 0 0
[ 1] .text PROGBITS 00000000 000034 000000 00 AX 0 0 2
[ 2] .data PROGBITS 00000000 000034 000000 00 WA 0 0 1
[ 3] .bss NOBITS 00000000 000034 000000 00 WA 0 0 1
[ 4] .gnu.lto_.profile PROGBITS 00000000 000034 00000f 00 E 0 0 1
[ 5] .gnu.lto_.icf.93e PROGBITS 00000000 000043 000017 00 E 0 0 1
[ 6] .gnu.lto_.jmpfunc PROGBITS 00000000 00005a 00000f 00 E 0 0 1
[ 7] .gnu.lto_.inline. PROGBITS 00000000 000069 00000f 00 E 0 0 1
[ 8] .gnu.lto_.purecon PROGBITS 00000000 000078 00000f 00 E 0 0 1
[ 9] .gnu.lto_.symbol_ PROGBITS 00000000 000087 000022 00 E 0 0 1
[10] .gnu.lto_.refs.93 PROGBITS 00000000 0000a9 00000f 00 E 0 0 1
[11] .gnu.lto_.decls.9 PROGBITS 00000000 0000b8 000239 00 E 0 0 1
[12] .gnu.lto_.symtab. PROGBITS 00000000 0002f1 00001d 00 E 0 0 1
[13] .gnu.lto_.opts PROGBITS 00000000 00030e 0000e8 00 E 0 0 1
[14] .comment PROGBITS 00000000 0003f6 00001e 01 MS 0 0 1
[15] .ARM.attributes ARM_ATTRIBUTES 00000000 000414 000033 00 0 0 1
[16] .shstrtab STRTAB 00000000 000447 00018c 00 0 0 1
[17] .symtab SYMTAB 00000000 0005d4 000130 10 18 17 4
[18] .strtab STRTAB 00000000 000704 00002c 00 0 0 1
Key to Flags:
W (write), A (alloc), X (execute), M (merge), S (strings)
I (info), L (link order), G (group), T (TLS), E (exclude), x (unknown)
O (extra OS processing required) o (OS specific), p (processor specific)
My linker script does not find the .the_header section, resulting in a corrupt binary.
I have tried specifying __attribute__((used)) for the header variable, with no effect.
Here's the relevant part of the linker script:
ENTRY(main)
MEMORY
{
APP (rwx) : ORIGIN = 0, LENGTH = 65536
}
SECTIONS
{
.header :
{
KEEP(*(.the_header))
} > APP
...
}
How do I tell GCC to emit .the_header into the final binary when using link time optimization and the above linker script snippet?