asm!: `push offset` causes `unexpected token!`

[toku-sa-n]

Code

#![feature(asm)]

fn main() {
    unsafe {
        asm!(
            "
            push offset 1f
            1:
            "
        );
    }
}

Expectation

Compilable as this assembly code follows the syntax of .intel_syntax noprefix.

Actual

The code will not compile, emitting these errors:

error: unexpected token!
 --> src/main.rs:7:13
  |
7 |             push offset 1f
  |             ^
  |
note: instantiated into assembly here
 --> <inline asm>:3:25
  |
3 |             push offset 1f
  |                         ^

error: aborting due to previous error

error: could not compile `rust`.

Other info

See the comments of the question I posted:
https://stackoverflow.com/questions/62989703/push-label-pushs-label-not-the-address-of-label-rust-asm?noredirect=1#62989703

The equivalent code written in GAS compiles with gcc:

    .intel_syntax noprefix

    .globl main

    .section text
main:
    push offset 1f
1:

Meta

rustc --version --verbose:

rustc 1.46.0-nightly (346aec9b0 2020-07-11)
binary: rustc
commit-hash: 346aec9b02f3c74f3fce97fd6bda24709d220e49
commit-date: 2020-07-11
host: x86_64-unknown-linux-gnu
release: 1.46.0-nightly
LLVM version: 10.0

[Amanieu]

This is a bug in LLVM's integrated assembler.

[Amanieu]

It seems that this is caused by LLVM's assembler interpreting 1b as an x86 binary literal rather than as a label. The workaround is to avoid using the 0: and 1: local labels for intel-syntax x86 code.

[pcordes]

The workaround is to avoid using the 0: and 1: local labels for intel-syntax x86 code.

That unfortunately doesn't work. 2: has the same problem, and it's not unique to a b suffix. In a stand-alone .s file:

.intel_syntax noprefix
   mov  edi, offset 2f         # fails
2:
   push  offset 2b           # also fails

$ clang -c foo.s
foo.s:2:18: error: unexpected token!
mov  edi, offset 2f
                 ^

foo.s:4:17: error: unexpected token!
   push  offset 2b
                ^

That's from clang version 11.0.0 (on x86-64 Arch GNU/Linux). Also, the GAS / LLVM syntax for binary constants is a 0b prefix, not a NASM-style b suffix. So 0b0101

mov  eax, 0b01         # valid,   mov eax, 1
mov  eax, 1b           # error: invalid reference to undefined symbol  (if you comment out 1: or put it after this instruction)

With 1: before mov eax, 1b, it assembles as a load from the label address, with an absolute [disp32] addressing mode.