compiler/rustc_target/src/spec/msp430_none_elf.rs

   1 use crate::spec::{LinkerFlavor, PanicStrategy, RelocModel, Target, TargetOptions, TargetResult};
   2
   3 pub fn target() -> TargetResult {
   4     Ok(Target {
   5         llvm_target: "msp430-none-elf".to_string(),
   6         target_endian: "little".to_string(),
   7         target_pointer_width: "16".to_string(),
   8         target_c_int_width: "16".to_string(),
   9         data_layout: "e-m:e-p:16:16-i32:16-i64:16-f32:16-f64:16-a:8-n8:16-S16".to_string(),
  10         arch: "msp430".to_string(),
  11         target_os: "none".to_string(),
  12         target_env: String::new(),
  13         target_vendor: String::new(),
  14         linker_flavor: LinkerFlavor::Gcc,
  15
  16         options: TargetOptions {
  17             executables: true,
  18
  19             // The LLVM backend currently can't generate object files. To
  20             // workaround this LLVM generates assembly files which then we feed
  21             // to gcc to get object files. For this reason we have a hard
  22             // dependency on this specific gcc.
  23             asm_args: vec!["-mcpu=msp430".to_string()],
  24             linker: Some("msp430-elf-gcc".to_string()),
  25
  26             // There are no atomic CAS instructions available in the MSP430
  27             // instruction set, and the LLVM backend doesn't currently support
  28             // compiler fences so the Atomic* API is missing on this target.
  29             // When the LLVM backend gains support for compile fences uncomment
  30             // the `singlethread: true` line and set `max_atomic_width` to
  31             // `Some(16)`.
  32             max_atomic_width: Some(0),
  33             atomic_cas: false,
  34             // singlethread: true,
  35
  36             // Because these devices have very little resources having an
  37             // unwinder is too onerous so we default to "abort" because the
  38             // "unwind" strategy is very rare.
  39             panic_strategy: PanicStrategy::Abort,
  40
  41             // Similarly, one almost always never wants to use relocatable
  42             // code because of the extra costs it involves.
  43             relocation_model: RelocModel::Static,
  44
  45             // Right now we invoke an external assembler and this isn't
  46             // compatible with multiple codegen units, and plus we probably
  47             // don't want to invoke that many gcc instances.
  48             default_codegen_units: Some(1),
  49
  50             // Since MSP430 doesn't meaningfully support faulting on illegal
  51             // instructions, LLVM generates a call to abort() function instead
  52             // of a trap instruction. Such calls are 4 bytes long, and that is
  53             // too much overhead for such small target.
  54             trap_unreachable: false,
  55
  56             // See the thumb_base.rs file for an explanation of this value
  57             emit_debug_gdb_scripts: false,
  58
  59             eh_frame_header: false,
  60
  61             ..Default::default()
  62         },
  63     })
  64 }