Compilation error for iOS (aarch64-apple-ios)

[filipw]

Building for aarch64-apple-ios produces the following error:

$ cargo build -p graviola --target aarch64-apple-ios
   Compiling libc v0.2.177
   Compiling cfg-if v1.0.4
   Compiling getrandom v0.3.4
   Compiling graviola v0.3.0 (/Users/filipw/dev/graviola/graviola)
error: ADR/ADRP relocations must be GOT relative
   --> graviola/src/low/aarch64/curve25519_x25519base.rs:431:9
    |
431 |         Q!("    adrp            " "x10, " PageRef!("curve25519_x25519base_alt_edwards25519_0g")),
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
note: instantiated into assembly here
   --> <inline asm>:13:26
    |
 13 |     adrp            x10, __ZN8graviola3low7aarch6421curve25519_x25519base41curve25519_x25519base_alt_edwards25519_0g17h1c5472b3dd5ad20dE
    |                          ^

error: unknown AArch64 fixup kind!
   --> graviola/src/low/aarch64/curve25519_x25519base.rs:431:9
    |
431 |         Q!("    adrp            " "x10, " PageRef!("curve25519_x25519base_alt_edwards25519_0g")),
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
note: instantiated into assembly here
   --> <inline asm>:13:26
    |
 13 |     adrp            x10, __ZN8graviola3low7aarch6421curve25519_x25519base41curve25519_x25519base_alt_edwards25519_0g17h1c5472b3dd5ad20dE
    |                          ^

error: ADR/ADRP relocations must be GOT relative
   --> graviola/src/low/aarch64/curve25519_x25519base.rs:432:9
    |
432 |         Q!("    adrp            " "x11, " PageRef!("curve25519_x25519base_alt_edwards25519_8g")),
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
note: instantiated into assembly here
   --> <inline asm>:14:26
    |
 14 |     adrp            x11, __ZN8graviola3low7aarch6421curve25519_x25519base41curve25519_x25519base_alt_edwards25519_8g17hcb13392432c6bc31E
    |                          ^

error: unknown AArch64 fixup kind!
   --> graviola/src/low/aarch64/curve25519_x25519base.rs:432:9
    |
432 |         Q!("    adrp            " "x11, " PageRef!("curve25519_x25519base_alt_edwards25519_8g")),
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
note: instantiated into assembly here
   --> <inline asm>:14:26
    |
 14 |     adrp            x11, __ZN8graviola3low7aarch6421curve25519_x25519base41curve25519_x25519base_alt_edwards25519_8g17hcb13392432c6bc31E
    |                          ^

error: ADR/ADRP relocations must be GOT relative
   --> graviola/src/low/aarch64/curve25519_x25519base.rs:488:9
    |
488 |         Q!("    adrp            " tab!() ", " PageRef!("curve25519_x25519base_alt_edwards25519_gtable")),
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
note: instantiated into assembly here
   --> <inline asm>:49:26
    |
 49 |     adrp            x19, __ZN8graviola3low7aarch6421curve25519_x25519base45curve25519_x25519base_alt_edwards25519_gtable17h38071b409089997fE
    |                          ^

error: unknown AArch64 fixup kind!
   --> graviola/src/low/aarch64/curve25519_x25519base.rs:488:9
    |
488 |         Q!("    adrp            " tab!() ", " PageRef!("curve25519_x25519base_alt_edwards25519_gtable")),
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
note: instantiated into assembly here
   --> <inline asm>:49:26
    |
 49 |     adrp            x19, __ZN8graviola3low7aarch6421curve25519_x25519base45curve25519_x25519base_alt_edwards25519_gtable17h38071b409089997fE
    |                          ^

error: could not compile `graviola` (lib) due to 6 previous errors

The problem seems to be that iOS (and other related Apple platforms that are non-Darwin) do not allow adrp direct addressing, you need to go over GOT.

So the fix would be something like this:

#[allow(unused_macros)]
#[cfg(all(target_vendor = "apple", not(target_os = "macos")))]
macro_rules! PageRef {
    ($sym:literal) => { Q!( "{" $sym "}@GOTPAGE" ) }
}

#[allow(unused_macros)]
#[cfg(not(target_vendor = "apple"))]
macro_rules! PageRef {
    ($sym:literal) => { Q!( "{" $sym "}" ) }
}

#[allow(unused_macros)]
#[cfg(target_os = "macos")]
macro_rules! GotLoad {
    ($reg:literal, $sym:literal) => {
        ""
    };
}

#[allow(unused_macros)]
#[cfg(all(target_vendor = "apple", not(target_os = "macos")))]
macro_rules! GotLoad {
    ($reg:literal, $sym:literal) => { Q!("    ldr             " $reg ", [" $reg ", " "{" $sym "}@GOTPAGEOFF" "]\n") }
}

#[allow(unused_macros)]
#[cfg(not(target_vendor = "apple"))]
macro_rules! GotLoad {
    ($reg:literal, $sym:literal) => {
        ""
    };
}

And then in the curve code:

        GotLoad!("x10", "curve25519_x25519base_alt_edwards25519_0g"),
        GotLoad!("x11", "curve25519_x25519base_alt_edwards25519_8g"),
....
        GotLoad!("x19", "curve25519_x25519base_alt_edwards25519_gtable")

which would be no-op everywhere but resolve the iOS issue.

[ctz]

Thanks for the report! I will also look into whether this is a problem upstream (where they are also doing some similar things to move the tables out of the text segment.)