Compiler panic when attempting to use non immediate as assembly parameter

[crawford]

Take the following code:

#![feature(asm)]

pub fn boot(addr: Option<u32>) {
    unsafe {
        asm!(
            "mov sp, $0"
             :
             : "r" (addr)
        );
    }
}

Attempting to compile this results in the following:

$ cargo build
   Compiling ice v0.1.0 (file:///home/alex/code/ice)                                                                                                                                           
error: internal compiler error: librustc_codegen_llvm/mir/operand.rs:145: not immediate: OperandRef(Pair((i32:  %7 = load i32, i32* %6, align 4, !dbg !29, !range !31), (i32:  %9 = load i32, i32* %8, align 4, !dbg !29)) @ TyLayout { ty: std::option::Option<u32>, details: LayoutDetails { variants: Tagged { tag: Scalar { value: Int(I32, false), valid_range: 0..=1 }, variants: [LayoutDetails { variants: Single { index: 0 }, fields: Arbitrary { offsets: [], memory_index: [] }, abi: Aggregate { sized: true }, align: Align { abi_pow2: 0, pref_pow2: 3 }, size: Size { raw: 4 } }, LayoutDetails { variants: Single { index: 1 }, fields: Arbitrary { offsets: [Size { raw: 4 }], memory_index: [0] }, abi: Aggregate { sized: true }, align: Align { abi_pow2: 2, pref_pow2: 3 }, size: Size { raw: 8 } }] }, fields: Arbitrary { offsets: [Size { raw: 0 }], memory_index: [0] }, abi: ScalarPair(Scalar { value: Int(I32, false), valid_range: 0..=1 }, Scalar { value: Int(I32, false), valid_range: 0..=4294967295 }), align: Align { abi_pow2: 2, pref_pow2: 3 }, size: Size { raw: 8 } } })

thread 'main' panicked at 'Box<Any>', librustc_errors/lib.rs:587:9
note: Run with `RUST_BACKTRACE=1` for a backtrace.
error: aborting due to previous error


note: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md#bug-reports

note: rustc 1.30.0-nightly (fc81e3624 2018-09-07) running on x86_64-unknown-linux-gnu

note: compiler flags: -C debuginfo=2 -C incremental --crate-type lib

note: some of the compiler flags provided by cargo are hidden

error: Could not compile `ice`.

I think the compiler should fail with something along the lines of "you attempted to use a complex type (Option<u32>) where I expected an immediate".

[alexandermerritt]

edit: not sure if these symptoms are the same, but here's what I stumbled across.

The following code generates a similar result for me:

// ice.rs
#![feature(asm)]
pub struct Foo {
    pub x: usize,
    pub y: usize
}
#[no_mangle]
pub unsafe fn ice() -> () {
    let bar: Foo = Foo { x: 0, y: 0 };
    asm!("lgdt %0" : : "m" (bar) : : );
}
fn main() { }
// EOF

The no_mangle and struct Foo seem to be required, else the ICE is not triggered.

Output

% rustc ice.rs
error: internal compiler error: librustc_codegen_llvm/mir/operand.rs:144: not immediate: OperandRef(Pair((i64:  %5 = load i64, i64* %4, align 8), (i64:  %7 = load i64, i64* %6, align 8)) @ TyLayout { ty: Foo, details: LayoutDetails { variants: Single { index: 0 }, fields: Arbitrary { offsets: [Size { raw: 0 }, Size { raw: 8 }], memory_index: [0, 1] }, abi: ScalarPair(Scalar { value: Int(I64, false), valid_range: 0..=18446744073709551615 }, Scalar { value: Int(I64, false), valid_range: 0..=18446744073709551615 }), align: Align { abi_pow2: 3, pref_pow2: 3 }, size: Size { raw: 16 } } })

thread 'main' panicked at 'Box<Any>', librustc_errors/lib.rs:587:9
stack backtrace:
   0: std::sys::unix::backtrace::tracing::imp::unwind_backtrace
             at libstd/sys/unix/backtrace/tracing/gcc_s.rs:49
   1: std::sys_common::backtrace::print
             at libstd/sys_common/backtrace.rs:71
             at libstd/sys_common/backtrace.rs:59
   2: std::panicking::default_hook::{{closure}}
             at libstd/panicking.rs:211
   3: std::panicking::default_hook
             at libstd/panicking.rs:227
   4: rustc::util::common::panic_hook
   5: std::panicking::rust_panic_with_hook
             at libstd/panicking.rs:481
   6: std::panicking::begin_panic
   7: rustc_errors::Handler::bug
   8: rustc::util::bug::opt_span_bug_fmt::{{closure}}
   9: rustc::ty::context::tls::with_opt::{{closure}}
  10: rustc::ty::context::tls::with_context_opt
  11: rustc::ty::context::tls::with_opt
  12: rustc::util::bug::opt_span_bug_fmt
  13: rustc::util::bug::bug_fmt
  14: <alloc::vec::Vec<T> as alloc::vec::SpecExtend<T, I>>::from_iter
  15: rustc_codegen_llvm::mir::codegen_mir
  16: rustc_codegen_llvm::base::codegen_instance
  17: rustc_codegen_llvm::mono_item::MonoItemExt::define
  18: rustc_codegen_llvm::base::compile_codegen_unit::module_codegen
  19: rustc::dep_graph::graph::DepGraph::with_task
  20: rustc_codegen_llvm::base::codegen_crate
  21: <rustc_codegen_llvm::LlvmCodegenBackend as rustc_codegen_utils::codegen_backend::CodegenBackend>::codegen_crate
  22: rustc::util::common::time
  23: rustc_driver::driver::phase_4_codegen
  24: rustc_driver::driver::compile_input::{{closure}}
  25: rustc::ty::context::tls::enter_context
  26: <std::thread::local::LocalKey<T>>::with
  27: rustc::ty::context::TyCtxt::create_and_enter
  28: rustc_driver::driver::compile_input
  29: rustc_driver::run_compiler_with_pool
  30: <scoped_tls::ScopedKey<T>>::set
  31: rustc_driver::run_compiler
  32: syntax::with_globals
  33: __rust_maybe_catch_panic
             at libpanic_unwind/lib.rs:103
  34: rustc_driver::run
  35: rustc_driver::main
  36: std::rt::lang_start::{{closure}}
  37: std::panicking::try::do_call
             at libstd/rt.rs:59
             at libstd/panicking.rs:310
  38: __rust_maybe_catch_panic
             at libpanic_unwind/lib.rs:103
  39: std::rt::lang_start_internal
             at libstd/panicking.rs:289
             at libstd/panic.rs:392
             at libstd/rt.rs:58
  40: main
  41: __libc_start_main
  42: <unknown>
query stack during panic:
end of query stack
error: aborting due to previous error


note: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md#bug-reports

note: rustc 1.30.0-nightly (2f1547c0a 2018-09-11) running on x86_64-unknown-linux-gnu

[levex]

No longer reproduces:

$ rustc +nightly -vV
rustc 1.31.0-nightly (77af31408 2018-10-11)
binary: rustc
commit-hash: 77af314083e5acabf9ba5335e47271f35eef2e99
commit-date: 2018-10-11
host: x86_64-unknown-linux-gnu
release: 1.31.0-nightly
LLVM version: 8.0
$ rustc +nightly 54067.rs 
error[E0669]: invalid value for constraint in inline assembly
  --> 54067.rs:9:9
   |
9  | /         asm!(
10 | |             "mov sp, $0"
11 | |              :
12 | |              : "r" (addr)
13 | |         );
   | |__________^

error: aborting due to previous error

For more information about this error, try `rustc --explain E0669`.