compiler/rustc_target/src/spec/thumbv4t_none_eabi.rs

   1 //! Targets the ARMv4T, with code as `t32` code by default.
   2 //!
   3 //! Primarily of use for the GBA, but usable with other devices too.
   4 //!
   5 //! Please ping @Lokathor if changes are needed.
   6 //!
   7 //! This target profile assumes that you have the ARM binutils in your path
   8 //! (specifically the linker, `arm-none-eabi-ld`). They can be obtained for free
   9 //! for all major OSes from the ARM developer's website, and they may also be
  10 //! available in your system's package manager. Unfortunately, the standard
  11 //! linker that Rust uses (`lld`) only supports as far back as `ARMv5TE`, so we
  12 //! must use the GNU `ld` linker.
  13 //!
  14 //! **Important:** This target profile **does not** specify a linker script. You
  15 //! just get the default link script when you build a binary for this target.
  16 //! The default link script is very likely wrong, so you should use
  17 //! `-Clink-arg=-Tmy_script.ld` to override that with a correct linker script.
  18
  19 use crate::spec::{
  20     cvs, FramePointer, LinkerFlavor, PanicStrategy, RelocModel, Target, TargetOptions,
  21 };
  22
  23 pub fn target() -> Target {
  24     Target {
  25         llvm_target: "thumbv4t-none-eabi".into(),
  26         pointer_width: 32,
  27         arch: "arm".into(),
  28         /* Data layout args are '-' separated:
  29          * little endian
  30          * stack is 64-bit aligned (EABI)
  31          * pointers are 32-bit
  32          * i64 must be 64-bit aligned (EABI)
  33          * mangle names with ELF style
  34          * native integers are 32-bit
  35          * All other elements are default
  36          */
  37         data_layout: "e-m:e-p:32:32-Fi8-i64:64-v128:64:128-a:0:32-n32-S64".into(),
  38         options: TargetOptions {
  39             abi: "eabi".into(),
  40             linker_flavor: LinkerFlavor::Ld,
  41             linker: Some("arm-none-eabi-ld".into()),
  42
  43             // extra args passed to the external assembler (assuming `arm-none-eabi-as`):
  44             // * activate t32/a32 interworking
  45             // * use arch ARMv4T
  46             // * use little-endian
  47             asm_args: cvs!["-mthumb-interwork", "-march=armv4t", "-mlittle-endian",],
  48
  49             // minimum extra features, these cannot be disabled via -C
  50             // Also force-enable 32-bit atomics, which allows the use of atomic load/store only.
  51             // The resulting atomics are ABI incompatible with atomics backed by libatomic.
  52             features: "+soft-float,+strict-align,+atomics-32".into(),
  53
  54             panic_strategy: PanicStrategy::Abort,
  55             relocation_model: RelocModel::Static,
  56             // suggested from thumb_base, rust-lang/rust#44993.
  57             emit_debug_gdb_scripts: false,
  58             // suggested from thumb_base, with no-os gcc/clang use 8-bit enums
  59             c_enum_min_bits: 8,
  60             frame_pointer: FramePointer::MayOmit,
  61
  62             main_needs_argc_argv: false,
  63
  64             // don't have atomic compare-and-swap
  65             atomic_cas: false,
  66             has_thumb_interworking: true,
  67
  68             ..super::thumb_base::opts()
  69         },
  70     }
  71 }