vendor/cranelift-codegen/src/prelude.isle

;; This is a prelude of standard definitions for ISLE, the instruction-selector
;; DSL, as we use it bound to our interfaces.
;;
;; Note that all `extern` functions here are typically defined in the
;; `isle_prelude_methods` macro defined in `src/isa/isle.rs`

;;;; Primitive and External Types ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

;; `()`
(type Unit (primitive Unit))

;; `bool` is declared in `clif.isle`.
(extern const $true bool)
(extern const $false bool)

(type u8 (primitive u8))
(type u16 (primitive u16))
(type u32 (primitive u32))
(type u64 (primitive u64))
(type u128 (primitive u128))
(type usize (primitive usize))

(type i8 (primitive i8))
(type i16 (primitive i16))
(type i32 (primitive i32))
(type i64 (primitive i64))
(type i128 (primitive i128))
(type isize (primitive isize))

;; `cranelift-entity`-based identifiers.
(type Inst (primitive Inst))
(type Type (primitive Type))
(type Value (primitive Value))

;; ISLE representation of `&[Value]`.
(type ValueSlice (primitive ValueSlice))

;; ISLE representation of `Vec<u8>`
(type VecMask extern (enum))

(type ValueList (primitive ValueList))
(type ValueRegs (primitive ValueRegs))
(type WritableValueRegs (primitive WritableValueRegs))

;; Instruction lowering result: a vector of `ValueRegs`.
(type InstOutput (primitive InstOutput))
;; (Mutable) builder to incrementally construct an `InstOutput`.
(type InstOutputBuilder extern (enum))

(decl u32_add (u32 u32) u32)
(extern constructor u32_add u32_add)

;; Pure/fallible constructor that tries to add two `u32`s, interpreted
;; as signed values, and fails to match on overflow.
(decl pure s32_add_fallible (u32 u32) u32)
(extern constructor s32_add_fallible s32_add_fallible)

;; Extractor that matches a `u32` only if non-negative.
(decl u32_nonnegative (u32) u32)
(extern extractor u32_nonnegative u32_nonnegative)

;; Extractor that pulls apart an Offset32 into a u32 with the raw
;; signed-32-bit twos-complement bits.
(decl offset32 (u32) Offset32)
(extern extractor offset32 offset32)

;; Pure/fallible constructor that tests if one u32 is less than or
;; equal to another.
(decl pure u32_lteq (u32 u32) Unit)
(extern constructor u32_lteq u32_lteq)

;; Get a signed 32-bit immediate in an u32 from an Imm64, if possible.
(decl simm32 (u32) Imm64)
(extern extractor simm32 simm32)

;; Get an unsigned 8-bit immediate in a u8 from an Imm64, if possible.
(decl uimm8 (u8) Imm64)
(extern extractor uimm8 uimm8)

(decl u8_and (u8 u8) u8)
(extern constructor u8_and u8_and)

;;;; Registers ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

(type Reg (primitive Reg))
(type WritableReg (primitive WritableReg))
(type OptionWritableReg (primitive OptionWritableReg))
(type VecReg extern (enum))
(type VecWritableReg extern (enum))
(type PReg (primitive PReg))

;; Construct a `ValueRegs` of one register.
(decl value_reg (Reg) ValueRegs)
(extern constructor value_reg value_reg)

;; Construct a `ValueRegs` of two registers.
(decl value_regs (Reg Reg) ValueRegs)
(extern constructor value_regs value_regs)

;; Construct an empty `ValueRegs` containing only invalid register sentinels.
(decl value_regs_invalid () ValueRegs)
(extern constructor value_regs_invalid value_regs_invalid)

;; Construct an empty `InstOutput`.
(decl output_none () InstOutput)
(extern constructor output_none output_none)

;; Construct a single-element `InstOutput`.
(decl output (ValueRegs) InstOutput)
(extern constructor output output)

;; Construct a two-element `InstOutput`.
(decl output_pair (ValueRegs ValueRegs) InstOutput)
(extern constructor output_pair output_pair)

;; Construct a single-element `InstOutput` from a single register.
(decl output_reg (Reg) InstOutput)
(rule (output_reg reg) (output (value_reg reg)))

;; Construct a single-element `InstOutput` from a value.
(decl output_value (Value) InstOutput)
(rule (output_value val) (output (put_in_regs val)))

;; Initially empty `InstOutput` builder.
(decl output_builder_new () InstOutputBuilder)
(extern constructor output_builder_new output_builder_new)

;; Append a `ValueRegs` to an `InstOutput` under construction.
(decl output_builder_push (InstOutputBuilder ValueRegs) Unit)
(extern constructor output_builder_push output_builder_push)

;; Finish building an `InstOutput` incrementally.
(decl output_builder_finish (InstOutputBuilder) InstOutput)
(extern constructor output_builder_finish output_builder_finish)

;; Get a temporary register for writing.
(decl temp_writable_reg (Type) WritableReg)
(extern constructor temp_writable_reg temp_writable_reg)

;; Get a temporary register for reading.
(decl temp_reg (Type) Reg)
(rule (temp_reg ty)
      (writable_reg_to_reg (temp_writable_reg ty)))

;; Get or match the invalid register.
(decl invalid_reg () Reg)
(extern constructor invalid_reg invalid_reg)
(extern extractor invalid_reg invalid_reg_etor)

;; Match any register but the invalid register.
(decl valid_reg () Reg)
(extern extractor valid_reg valid_reg)

;; Mark this value as used, to ensure that it gets lowered.
(decl mark_value_used (Value) Unit)
(extern constructor mark_value_used mark_value_used)

;; Put the given value into a register.
;;
;; Asserts that the value fits into a single register, and doesn't require
;; multiple registers for its representation (like `i128` on x64 for example).
;;
;; As a side effect, this marks the value as used.
(decl put_in_reg (Value) Reg)
(extern constructor put_in_reg put_in_reg)

;; Put the given value into one or more registers.
;;
;; As a side effect, this marks the value as used.
(decl put_in_regs (Value) ValueRegs)
(extern constructor put_in_regs put_in_regs)

;; If the given reg is a real register, cause the value in reg to be in a virtual
;; reg, by copying it into a new virtual reg.
(decl ensure_in_vreg (Reg Type) Reg)
(extern constructor ensure_in_vreg ensure_in_vreg)

;; Get the `n`th register inside a `ValueRegs`.
(decl value_regs_get (ValueRegs usize) Reg)
(extern constructor value_regs_get value_regs_get)

;; Get the number of registers in a `ValueRegs`.
(decl value_regs_len (ValueRegs) usize)
(extern constructor value_regs_len value_regs_len)

;; Get a range for the number of regs in a `ValueRegs`.
(decl value_regs_range (ValueRegs) Range)
(rule (value_regs_range regs) (range 0 (value_regs_len regs)))

;; Put the value into one or more registers and return the first register.
;;
;; Unlike `put_in_reg`, this does not assert that the value fits in a single
;; register. This is useful for things like a `i128` shift amount, where we mask
;; the shift amount to the bit width of the value being shifted, and so the high
;; half of the `i128` won't ever be used.
;;
;; As a side efect, this marks that value as used.
(decl lo_reg (Value) Reg)
(rule (lo_reg val)
      (let ((regs ValueRegs (put_in_regs val)))
        (value_regs_get regs 0)))

;; Convert a `PReg` into a `Reg`
(decl preg_to_reg (PReg) Reg)
(extern constructor preg_to_reg preg_to_reg)

;;;; Common Mach Types ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

(type MachLabel (primitive MachLabel))
(type ValueLabel (primitive ValueLabel))
(type UnwindInst (primitive UnwindInst))
(type ExternalName (primitive ExternalName))
(type BoxExternalName (primitive BoxExternalName))
(type RelocDistance (primitive RelocDistance))

;;;; Primitive Type Conversions ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

(decl pure u8_as_u32 (u8) u32)
(extern constructor u8_as_u32 u8_as_u32)

(decl pure u8_as_u64 (u8) u64)
(extern constructor u8_as_u64 u8_as_u64)

(decl pure u16_as_u64 (u16) u64)
(extern constructor u16_as_u64 u16_as_u64)

(decl pure u32_as_u64 (u32) u64)
(extern constructor u32_as_u64 u32_as_u64)

(decl pure i64_as_u64 (i64) u64)
(extern constructor i64_as_u64 i64_as_u64)

;;;; Primitive Arithmetic ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

(decl pure u64_add (u64 u64) u64)
(extern constructor u64_add u64_add)

(decl pure u64_sub (u64 u64) u64)
(extern constructor u64_sub u64_sub)

(decl pure u64_and (u64 u64) u64)
(extern constructor u64_and u64_and)

;;;; `cranelift_codegen::ir::Type` ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

(extern const $B1 Type)
(extern const $B8 Type)
(extern const $B16 Type)
(extern const $B32 Type)
(extern const $B64 Type)
(extern const $B128 Type)

(extern const $I8 Type)
(extern const $I16 Type)
(extern const $I32 Type)
(extern const $I64 Type)
(extern const $I128 Type)

(extern const $R32 Type)
(extern const $R64 Type)

(extern const $F32 Type)
(extern const $F64 Type)

(extern const $B8X16 Type)
(extern const $B16X8 Type)
(extern const $B32X4 Type)
(extern const $B64X2 Type)

(extern const $I8X8 Type)
(extern const $I8X16 Type)
(extern const $I16X4 Type)
(extern const $I16X8 Type)
(extern const $I32X2 Type)
(extern const $I32X4 Type)
(extern const $I64X2 Type)

(extern const $F32X4 Type)
(extern const $F64X2 Type)

(extern const $I32X4XN Type)

;; Get the bit width of a given type.
(decl pure ty_bits (Type) u8)
(extern constructor ty_bits ty_bits)

;; Get the bit width of a given type.
(decl ty_bits_u16 (Type) u16)
(extern constructor ty_bits_u16 ty_bits_u16)

;; Get the bit width of a given type.
(decl ty_bits_u64 (Type) u64)
(extern constructor ty_bits_u64 ty_bits_u64)

;; Get a mask for the width of a given type.
(decl ty_mask (Type) u64)
(extern constructor ty_mask ty_mask)

;; Get the byte width of a given type.
(decl ty_bytes (Type) u16)
(extern constructor ty_bytes ty_bytes)

;; Get the type of each lane in the given type.
(decl lane_type (Type) Type)
(extern constructor lane_type lane_type)

;;;; `cranelift_codegen::ir::MemFlags ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

;; `MemFlags::trusted`
(decl mem_flags_trusted () MemFlags)
(extern constructor mem_flags_trusted mem_flags_trusted)

;;;; Helper Clif Extractors ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

;; An extractor that only matches types that can fit in 16 bits.
(decl fits_in_16 (Type) Type)
(extern extractor fits_in_16 fits_in_16)

;; An extractor that only matches types that can fit in 32 bits.
(decl fits_in_32 (Type) Type)
(extern extractor fits_in_32 fits_in_32)

;; An extractor that only matches types that can fit in 32 bits.
(decl lane_fits_in_32 (Type) Type)
(extern extractor lane_fits_in_32 lane_fits_in_32)

;; An extractor that only matches types that can fit in 64 bits.
(decl fits_in_64 (Type) Type)
(extern extractor fits_in_64 fits_in_64)

;; An extractor that only matches types that fit in exactly 32 bits.
(decl ty_32 (Type) Type)
(extern extractor ty_32 ty_32)

;; An extractor that only matches types that fit in exactly 64 bits.
(decl ty_64 (Type) Type)
(extern extractor ty_64 ty_64)

;; A pure constructor that only matches scalar booleans, integers, and
;; references that can fit in 64 bits.
(decl pure ty_int_bool_ref_scalar_64 (Type) Type)
(extern constructor ty_int_bool_ref_scalar_64 ty_int_bool_ref_scalar_64)

;; An extractor that matches 32- and 64-bit types only.
(decl ty_32_or_64 (Type) Type)
(extern extractor ty_32_or_64 ty_32_or_64)

;; An extractor that matches 8- and 16-bit types only.
(decl ty_8_or_16 (Type) Type)
(extern extractor ty_8_or_16 ty_8_or_16)

;; An extractor that matches int and bool types that fit in 32 bits.
(decl int_bool_fits_in_32 (Type) Type)
(extern extractor int_bool_fits_in_32 int_bool_fits_in_32)

;; An extractor that matches I64 or B64.
(decl ty_int_bool_64 (Type) Type)
(extern extractor ty_int_bool_64 ty_int_bool_64)

;; An extractor that matches I64 or B64 or R64.
(decl ty_int_bool_ref_64 (Type) Type)
(extern extractor ty_int_bool_ref_64 ty_int_bool_ref_64)

;; An extractor that matches I128 or B128.
(decl ty_int_bool_128 (Type) Type)
(extern extractor ty_int_bool_128 ty_int_bool_128)

;; An extractor that matches any int or bool.
(decl ty_int_bool (Type) Type)
(extern extractor ty_int_bool ty_int_bool)

;; An extractor that only matches integers.
(decl ty_int (Type) Type)
(extern extractor ty_int ty_int)

;; An extractor that only matches scalar floating-point types--F32 or F64.
(decl ty_scalar_float (Type) Type)
(extern extractor ty_scalar_float ty_scalar_float)

;; An extractor that matches scalar floating-point types or vector types.
(decl ty_float_or_vec (Type) Type)
(extern extractor ty_float_or_vec ty_float_or_vec)

;; A pure constructor that only matches vector floating-point types.
(decl pure ty_vector_float (Type) Type)
(extern constructor ty_vector_float ty_vector_float)

;; A pure constructor that only matches vector types with lanes which
;; are not floating-point.
(decl pure ty_vector_not_float (Type) Type)
(extern constructor ty_vector_not_float ty_vector_not_float)

;; A pure constructor/extractor that only matches 64-bit vector types.
(decl pure ty_vec64 (Type) Type)
(extern constructor ty_vec64 ty_vec64_ctor)
(extern extractor ty_vec64 ty_vec64)

;; An extractor that only matches 128-bit vector types.
(decl ty_vec128 (Type) Type)
(extern extractor ty_vec128 ty_vec128)

;; An extractor that only matches dynamic vector types with a 64-bit
;; base type.
(decl ty_dyn_vec64 (Type) Type)
(extern extractor ty_dyn_vec64 ty_dyn_vec64)

;; An extractor that only matches dynamic vector types with a 128-bit
;; base type.
(decl ty_dyn_vec128 (Type) Type)
(extern extractor ty_dyn_vec128 ty_dyn_vec128)

;; An extractor that only matches 64-bit vector types with integer
;; lanes (I8X8, I16X4, I32X2)
(decl ty_vec64_int (Type) Type)
(extern extractor ty_vec64_int ty_vec64_int)

;; An extractor that only matches 128-bit vector types with integer
;; lanes (I8X16, I16X8, I32X4, I64X2).
(decl ty_vec128_int (Type) Type)
(extern extractor ty_vec128_int ty_vec128_int)

;; A pure constructor that matches everything except vectors with size 32X2.
(decl pure not_vec32x2 (Type) Type)
(extern constructor not_vec32x2 not_vec32x2)

;; An extractor that matches everything except I64X2
(decl not_i64x2 () Type)
(extern extractor not_i64x2 not_i64x2)

;; Extractor to get a `ValueSlice` out of a `ValueList`.
(decl value_list_slice (ValueSlice) ValueList)
(extern extractor infallible value_list_slice value_list_slice)

;; Extractor to test whether a `ValueSlice` is empty.
(decl value_slice_empty () ValueSlice)
(extern extractor value_slice_empty value_slice_empty)

;; Extractor to split a `ValueSlice` into its first element plus a tail.
(decl value_slice_unwrap (Value ValueSlice) ValueSlice)
(extern extractor value_slice_unwrap value_slice_unwrap)

;; Return the length of a `ValueSlice`.
(decl value_slice_len (ValueSlice) usize)
(extern constructor value_slice_len value_slice_len)

;; Return any element of a `ValueSlice`.
(decl value_slice_get (ValueSlice usize) Value)
(extern constructor value_slice_get value_slice_get)

;; Extractor to get the first element from a value list, along with its tail as
;; a `ValueSlice`.
(decl unwrap_head_value_list_1 (Value ValueSlice) ValueList)
(extractor (unwrap_head_value_list_1 head tail)
           (value_list_slice (value_slice_unwrap head tail)))

;; Extractor to get the first two elements from a value list, along with its
;; tail as a `ValueSlice`.
(decl unwrap_head_value_list_2 (Value Value ValueSlice) ValueList)
(extractor (unwrap_head_value_list_2 head1 head2 tail)
           (value_list_slice (value_slice_unwrap head1 (value_slice_unwrap head2 tail))))

;; Constructor to test whether two values are same.
(decl pure same_value (Value Value) Value)
(extern constructor same_value same_value)

;; Turn a `Writable<Reg>` into a `Reg` via `Writable::to_reg`.
(decl writable_reg_to_reg (WritableReg) Reg)
(extern constructor writable_reg_to_reg writable_reg_to_reg)

;; Extract a `u8` from an `Uimm8`.
(decl u8_from_uimm8 (u8) Uimm8)
(extern extractor infallible u8_from_uimm8 u8_from_uimm8)

;; Extract a `u64` from a `bool`.
(decl u64_from_bool (u64) bool)
(extern extractor infallible u64_from_bool u64_from_bool)

;; Extract a `u64` from an `Imm64`.
(decl u64_from_imm64 (u64) Imm64)
(extern extractor infallible u64_from_imm64 u64_from_imm64)

;; Extract a `u64` from an `Imm64` which is not zero.
(decl nonzero_u64_from_imm64 (u64) Imm64)
(extern extractor nonzero_u64_from_imm64 nonzero_u64_from_imm64)

;; Extract a `u64` from an `Ieee32`.
(decl u64_from_ieee32 (u64) Ieee32)
(extern extractor infallible u64_from_ieee32 u64_from_ieee32)

;; Extract a `u64` from an `Ieee64`.
(decl u64_from_ieee64 (u64) Ieee64)
(extern extractor infallible u64_from_ieee64 u64_from_ieee64)

;; Extract the result values for the given instruction.
(decl inst_results (ValueSlice) Inst)
(extern extractor infallible inst_results inst_results)

;; Extract the first result value of the given instruction.
(decl first_result (Value) Inst)
(extern extractor first_result first_result)

;; Extract the `InstructionData` for an `Inst`.
(decl inst_data (InstructionData) Inst)
(extern extractor infallible inst_data inst_data)

;; Extract the type of a `Value`.
(decl value_type (Type) Value)
(extern extractor infallible value_type value_type)

;; Extract the type of the instruction's first result.
(decl result_type (Type) Inst)
(extractor (result_type ty)
           (first_result (value_type ty)))

;; Extract the type of the instruction's first result and pass along the
;; instruction as well.
(decl has_type (Type Inst) Inst)
(extractor (has_type ty inst)
           (and (result_type ty)
                inst))

;; Match a multi-lane type, extracting (# bits per lane, # lanes) from the given
;; type. Will only match when there is more than one lane.
(decl multi_lane (u32 u32) Type)
(extern extractor multi_lane multi_lane)

;; Match a dynamic-lane type, extracting (# bits per lane) from the given
;; type.
(decl dynamic_lane (u32 u32) Type)
(extern extractor dynamic_lane dynamic_lane)

;; Match a dynamic-lane integer type, extracting (# bits per lane) from the given
;; type.
(decl dynamic_int_lane (u32) Type)
(extern extractor dynamic_int_lane dynamic_int_lane)

;; Match a dynamic-lane floating point type, extracting (# bits per lane)
;; from the given type.
(decl dynamic_fp_lane (u32) Type)
(extern extractor dynamic_fp_lane dynamic_fp_lane)

;; An extractor that only matches 64-bit dynamic vector types with integer
;; lanes (I8X8XN, I16X4XN, I32X2XN)
(decl ty_dyn64_int (Type) Type)
(extern extractor ty_dyn64_int ty_dyn64_int)

;; An extractor that only matches 128-bit dynamic vector types with integer
;; lanes (I8X16XN, I16X8XN, I32X4XN, I64X2XN).
(decl ty_dyn128_int (Type) Type)
(extern extractor ty_dyn128_int ty_dyn128_int)

;; Match the instruction that defines the given value, if any.
(decl def_inst (Inst) Value)
(extern extractor def_inst def_inst)

;; Extract a constant `u64` from a value defined by an `iconst`.
(decl u64_from_iconst (u64) Value)
(extractor (u64_from_iconst x)
           (def_inst (iconst (u64_from_imm64 x))))

;; Convert an `Offset32` to a primitive number.
(decl offset32_to_u32 (Offset32) u32)
(extern constructor offset32_to_u32 offset32_to_u32)

;; Match any zero value for iconst, fconst32, fconst64, vconst and splat.
(decl pure zero_value (Value) Value)
(extern constructor zero_value zero_value)

;; Match a sinkable instruction from a value operand.
(decl pure is_sinkable_inst (Value) Inst)
(extern constructor is_sinkable_inst is_sinkable_inst)

;; Instruction creation helpers ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

;; Emit an instruction.
;;
;; This is low-level and side-effectful; it should only be used as an
;; implementation detail by helpers that preserve the SSA facade themselves.

(decl emit (MInst) Unit)
(extern constructor emit emit)

;; Sink an instruction.
;;
;; This is a side-effectful operation that notifies the context that the
;; instruction has been sunk into another instruction, and no longer needs to
;; be lowered.
(decl sink_inst (Inst) Unit)
(extern constructor sink_inst sink_inst)

;; Constant pool emission.

(type VCodeConstant (primitive VCodeConstant))

;; Add a u64 little-endian constant to the in-memory constant pool and
;; return a VCodeConstant index that refers to it. This is
;; side-effecting but idempotent (constants are deduplicated).
(decl emit_u64_le_const (u64) VCodeConstant)
(extern constructor emit_u64_le_const emit_u64_le_const)

;; Add a u128 little-endian constant to the in-memory constant pool and
;; return a VCodeConstant index that refers to it. This is
;; side-effecting but idempotent (constants are deduplicated).
(decl emit_u128_le_const (u128) VCodeConstant)
(extern constructor emit_u128_le_const emit_u128_le_const)

;; Fetch the VCodeConstant associated with a Constant.
(decl const_to_vconst (Constant) VCodeConstant)
(extern constructor const_to_vconst const_to_vconst)

;;;; Helpers for Side-Effectful Instructions Without Results ;;;;;;;;;;;;;;;;;;;

(type SideEffectNoResult (enum
                          (Inst (inst MInst))
                          (Inst2 (inst1 MInst)
                                 (inst2 MInst))
                          (Inst3 (inst1 MInst)
                                 (inst2 MInst)
                                 (inst3 MInst))))

;; Create an empty `InstOutput`, but do emit the given side-effectful
;; instruction.
(decl side_effect (SideEffectNoResult) InstOutput)
(rule (side_effect (SideEffectNoResult.Inst inst))
      (let ((_ Unit (emit inst)))
        (output_none)))
(rule (side_effect (SideEffectNoResult.Inst2 inst1 inst2))
      (let ((_ Unit (emit inst1))
            (_ Unit (emit inst2)))
        (output_none)))
(rule (side_effect (SideEffectNoResult.Inst3 inst1 inst2 inst3))
      (let ((_ Unit (emit inst1))
            (_ Unit (emit inst2))
            (_ Unit (emit inst3)))
        (output_none)))

(decl side_effect_concat (SideEffectNoResult SideEffectNoResult) SideEffectNoResult)
(rule (side_effect_concat (SideEffectNoResult.Inst inst1) (SideEffectNoResult.Inst inst2))
      (SideEffectNoResult.Inst2 inst1 inst2))
(rule (side_effect_concat (SideEffectNoResult.Inst inst1) (SideEffectNoResult.Inst2 inst2 inst3))
      (SideEffectNoResult.Inst3 inst1 inst2 inst3))
(rule (side_effect_concat (SideEffectNoResult.Inst2 inst1 inst2) (SideEffectNoResult.Inst inst3))
      (SideEffectNoResult.Inst3 inst1 inst2 inst3))

;;;; Helpers for Working with Flags ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

;; Newtype wrapper around `MInst` for instructions that are used for their
;; effect on flags.
;;
;; Variant determines how result is given when combined with a
;; ConsumesFlags. See `with_flags` below for more.
(type ProducesFlags (enum
                     ;; For cases where the flags have been produced by another
                     ;; instruction, and we have out-of-band reasons to know
                     ;; that they won't be clobbered by the time we depend on
                     ;; them.
                     (AlreadyExistingFlags)
                     (ProducesFlagsSideEffect (inst MInst))
                     ;; Not directly combinable with a ConsumesFlags;
                     ;; used in s390x and unwrapped directly by `trapif`.
                     (ProducesFlagsReturnsReg (inst MInst) (result Reg))
                     (ProducesFlagsReturnsResultWithConsumer (inst MInst) (result Reg))))

;; Newtype wrapper around `MInst` for instructions that consume flags.
;;
;; Variant determines how result is given when combined with a
;; ProducesFlags. See `with_flags` below for more.
(type ConsumesFlags (enum
                     (ConsumesFlagsSideEffect (inst MInst))
                     (ConsumesFlagsSideEffect2 (inst1 MInst) (inst2 MInst))
                     (ConsumesFlagsReturnsResultWithProducer (inst MInst) (result Reg))
                     (ConsumesFlagsReturnsReg (inst MInst) (result Reg))
                     (ConsumesFlagsTwiceReturnsValueRegs (inst1 MInst)
                                                         (inst2 MInst)
                                                         (result ValueRegs))
                     (ConsumesFlagsFourTimesReturnsValueRegs (inst1 MInst)
                                                             (inst2 MInst)
                                                             (inst3 MInst)
                                                             (inst4 MInst)
                                                             (result ValueRegs))))



;; Get the produced register out of a ProducesFlags.
(decl produces_flags_get_reg (ProducesFlags) Reg)
(rule (produces_flags_get_reg (ProducesFlags.ProducesFlagsReturnsReg _ reg)) reg)

;; Modify a ProducesFlags to use it only for its side-effect, ignoring
;; its result.
(decl produces_flags_ignore (ProducesFlags) ProducesFlags)
(rule (produces_flags_ignore (ProducesFlags.ProducesFlagsReturnsReg inst _))
                             (ProducesFlags.ProducesFlagsSideEffect inst))
(rule (produces_flags_ignore (ProducesFlags.ProducesFlagsReturnsResultWithConsumer inst _))
                             (ProducesFlags.ProducesFlagsSideEffect inst))

;; Helper for combining two flags-consumer instructions that return a
;; single Reg, giving a ConsumesFlags that returns both values in a
;; ValueRegs.
(decl consumes_flags_concat (ConsumesFlags ConsumesFlags) ConsumesFlags)
(rule (consumes_flags_concat (ConsumesFlags.ConsumesFlagsReturnsReg inst1 reg1)
                             (ConsumesFlags.ConsumesFlagsReturnsReg inst2 reg2))
      (ConsumesFlags.ConsumesFlagsTwiceReturnsValueRegs
       inst1
       inst2
       (value_regs reg1 reg2)))
(rule (consumes_flags_concat
        (ConsumesFlags.ConsumesFlagsSideEffect inst1)
        (ConsumesFlags.ConsumesFlagsSideEffect inst2))
      (ConsumesFlags.ConsumesFlagsSideEffect2 inst1 inst2))

;; Combine flags-producing and -consuming instructions together, ensuring that
;; they are emitted back-to-back and no other instructions can be emitted
;; between them and potentially clobber the flags.
;;
;; Returns a `ValueRegs` according to the specific combination of ProducesFlags and ConsumesFlags modes:
;; - SideEffect + ReturnsReg --> ValueReg with one Reg from consumer
;; - SideEffect + ReturnsValueRegs --> ValueReg as given from consumer
;; - ReturnsResultWithProducer + ReturnsResultWithConsumer --> ValueReg with low part from producer, high part from consumer
;;
;; See `with_flags_reg` below for a variant that extracts out just the lower Reg.
(decl with_flags (ProducesFlags ConsumesFlags) ValueRegs)

(rule (with_flags (ProducesFlags.ProducesFlagsReturnsResultWithConsumer producer_inst producer_result)
                  (ConsumesFlags.ConsumesFlagsReturnsResultWithProducer consumer_inst consumer_result))
      (let ((_x Unit (emit producer_inst))
            (_y Unit (emit consumer_inst)))
        (value_regs producer_result consumer_result)))

(rule (with_flags (ProducesFlags.ProducesFlagsSideEffect producer_inst)
                  (ConsumesFlags.ConsumesFlagsReturnsReg consumer_inst consumer_result))
      (let ((_x Unit (emit producer_inst))
            (_y Unit (emit consumer_inst)))
        (value_reg consumer_result)))

(rule (with_flags (ProducesFlags.ProducesFlagsSideEffect producer_inst)
                  (ConsumesFlags.ConsumesFlagsTwiceReturnsValueRegs consumer_inst_1
                                                                    consumer_inst_2
                                                                    consumer_result))
      ;; We must emit these instructions in order as the creator of
      ;; the ConsumesFlags may be relying on dataflow dependencies
      ;; amongst them.
      (let ((_x Unit (emit producer_inst))
            (_y Unit (emit consumer_inst_1))
            (_z Unit (emit consumer_inst_2)))
        consumer_result))

(rule (with_flags (ProducesFlags.ProducesFlagsSideEffect producer_inst)
                  (ConsumesFlags.ConsumesFlagsFourTimesReturnsValueRegs consumer_inst_1
                                                                        consumer_inst_2
                                                                        consumer_inst_3
                                                                        consumer_inst_4
                                                                        consumer_result))
      ;; We must emit these instructions in order as the creator of
      ;; the ConsumesFlags may be relying on dataflow dependencies
      ;; amongst them.
      (let ((_x Unit (emit producer_inst))
            (_y Unit (emit consumer_inst_1))
            (_z Unit (emit consumer_inst_2))
            (_w Unit (emit consumer_inst_3))
            (_v Unit (emit consumer_inst_4)))
        consumer_result))

(decl with_flags_reg (ProducesFlags ConsumesFlags) Reg)
(rule (with_flags_reg p c)
      (let ((v ValueRegs (with_flags p c)))
        (value_regs_get v 0)))

;; Indicate that the current state of the flags register from the instruction
;; that produces this Value is relied on.
(decl flags_to_producesflags (Value) ProducesFlags)
(rule (flags_to_producesflags val)
      (let ((_ Unit (mark_value_used val)))
        (ProducesFlags.AlreadyExistingFlags)))

;; Combine a flags-producing instruction and a flags-consuming instruction that
;; produces no results.
;;
;; This function handles the following case only:
;; - ProducesFlagsSideEffect + ConsumesFlagsSideEffect
(decl with_flags_side_effect (ProducesFlags ConsumesFlags) SideEffectNoResult)

(rule (with_flags_side_effect
        (ProducesFlags.AlreadyExistingFlags)
        (ConsumesFlags.ConsumesFlagsSideEffect c))
      (SideEffectNoResult.Inst c))

(rule (with_flags_side_effect
        (ProducesFlags.AlreadyExistingFlags)
        (ConsumesFlags.ConsumesFlagsSideEffect2 c1 c2))
      (SideEffectNoResult.Inst2 c1 c2))

(rule (with_flags_side_effect
        (ProducesFlags.ProducesFlagsSideEffect p)
        (ConsumesFlags.ConsumesFlagsSideEffect c))
      (SideEffectNoResult.Inst2 p c))

(rule (with_flags_side_effect
        (ProducesFlags.ProducesFlagsSideEffect p)
        (ConsumesFlags.ConsumesFlagsSideEffect2 c1 c2))
      (SideEffectNoResult.Inst3 p c1 c2))

;;;; Helpers for Working with TrapCode ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

(decl trap_code_division_by_zero () TrapCode)
(extern constructor trap_code_division_by_zero trap_code_division_by_zero)

(decl trap_code_integer_overflow () TrapCode)
(extern constructor trap_code_integer_overflow trap_code_integer_overflow)

(decl trap_code_bad_conversion_to_integer () TrapCode)
(extern constructor trap_code_bad_conversion_to_integer trap_code_bad_conversion_to_integer)

;;;; Helpers for accessing compilation flags ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

(decl avoid_div_traps () Type)
(extern extractor avoid_div_traps avoid_div_traps)

(decl pure tls_model_is_elf_gd () Unit)
(extern constructor tls_model_is_elf_gd tls_model_is_elf_gd)

(decl pure tls_model_is_macho () Unit)
(extern constructor tls_model_is_macho tls_model_is_macho)

(decl pure tls_model_is_coff () Unit)
(extern constructor tls_model_is_coff tls_model_is_coff)

;;;; Helpers for accessing instruction data ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

;; Accessor for `FuncRef`.

(decl func_ref_data (SigRef ExternalName RelocDistance) FuncRef)
(extern extractor infallible func_ref_data func_ref_data)

;; Accessor for `GobalValue`.

(decl symbol_value_data (ExternalName RelocDistance i64) GlobalValue)
(extern extractor symbol_value_data symbol_value_data)

(decl box_external_name (ExternalName) BoxExternalName)
(extern constructor box_external_name box_external_name)

;; Accessor for `RelocDistance`.

(decl reloc_distance_near () RelocDistance)
(extern extractor reloc_distance_near reloc_distance_near)

;; Accessor for `Immediate` as u128.

(decl u128_from_immediate (u128) Immediate)
(extern extractor u128_from_immediate u128_from_immediate)

;; Accessor for `Immediate` as a vector of u8 values.

(decl vec_mask_from_immediate (VecMask) Immediate)
(extern extractor vec_mask_from_immediate vec_mask_from_immediate)

;; Accessor for `Constant` as u128.

(decl u128_from_constant (u128) Constant)
(extern extractor u128_from_constant u128_from_constant)

;; Accessor for `Constant` as u64.

(decl u64_from_constant (u64) Constant)
(extern extractor u64_from_constant u64_from_constant)

;;;; Helpers for tail recursion loops ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

;; A range of integers to loop through.
(type Range (primitive Range))

;; Create a new range from `start` through `end` (exclusive).
(decl range (usize usize) Range)
(extern constructor range range)

;; Extractor to test whether a range is empty.
(decl range_empty () Range)
(extern extractor range_empty range_empty)

;; Extractor to test whether a range has a single element in it
(decl range_singleton (usize) Range)
(extern extractor range_singleton range_singleton)

;; Extractor to return the first value in the range, and a sub-range
;; containing the remaining values.
(decl range_unwrap (usize Range) Range)
(extern extractor range_unwrap range_unwrap)

;;;; Helpers for generating returns ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

;; The (writable) register(s) that will contain the n'th return value.
(decl retval (usize) WritableValueRegs)
(extern constructor retval retval)

;; Extractor to check for the special case that a `WritableValueRegs`
;; contains only a single register.
(decl only_writable_reg (WritableReg) WritableValueRegs)
(extern extractor only_writable_reg only_writable_reg)

;; Get the `n`th register inside a `WritableValueRegs`.
(decl writable_regs_get (WritableValueRegs usize) WritableReg)
(extern constructor writable_regs_get writable_regs_get)

;;;; Helpers for generating calls ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

;; Type to hold information about a function call signature.
(type Sig extern (enum))

;; Information how to pass one argument or return value.
(type ABIArg extern (enum))

;; Information how to pass a single slot of one argument or return value.
(type ABIArgSlot extern
  (enum
    (Reg
      (reg RealReg)
      (ty Type)
      (extension ArgumentExtension))
    (Stack
      (offset i64)
      (ty Type)
      (extension ArgumentExtension))
))

;; Physical register that may hold an argument or return value.
(type RealReg (primitive RealReg))

;; Instruction on whether and how to extend an argument value.
(type ArgumentExtension extern
  (enum
    (None)
    (Uext)
    (Sext)
))

;; Get the number of arguments expected.
(decl abi_num_args (Sig) usize)
(extern constructor abi_num_args abi_num_args)

;; Get information specifying how to pass one argument.
(decl abi_get_arg (Sig usize) ABIArg)
(extern constructor abi_get_arg abi_get_arg)

;; Get the number of return values expected.
(decl abi_num_rets (Sig) usize)
(extern constructor abi_num_rets abi_num_rets)

;; Get information specifying how to pass one return value.
(decl abi_get_ret (Sig usize) ABIArg)
(extern constructor abi_get_ret abi_get_ret)

;; Get information specifying how to pass the implicit pointer
;; to the return-value area on the stack, if required.
(decl abi_ret_arg (ABIArg) Sig)
(extern extractor abi_ret_arg abi_ret_arg)

;; Succeeds if no implicit return-value area pointer is required.
(decl abi_no_ret_arg () Sig)
(extern extractor abi_no_ret_arg abi_no_ret_arg)

;; Size of the argument area.
(decl abi_sized_stack_arg_space (Sig) i64)
(extern constructor abi_sized_stack_arg_space abi_sized_stack_arg_space)

;; Size of the return-value area.
(decl abi_sized_stack_ret_space (Sig) i64)
(extern constructor abi_sized_stack_ret_space abi_sized_stack_ret_space)

;; StackSlot addr
(decl abi_stackslot_addr (WritableReg StackSlot Offset32) MInst)
(extern constructor abi_stackslot_addr abi_stackslot_addr)

;; DynamicStackSlot addr
(decl abi_dynamic_stackslot_addr (WritableReg DynamicStackSlot) MInst)
(extern constructor abi_dynamic_stackslot_addr abi_dynamic_stackslot_addr)

;; Extractor to detect the special case where an argument or
;; return value only requires a single slot to be passed.
(decl abi_arg_only_slot (ABIArgSlot) ABIArg)
(extern extractor abi_arg_only_slot abi_arg_only_slot)

;; Extractor to detect the special case where a struct argument
;; is explicitly passed by reference using a hidden pointer.
(decl abi_arg_struct_pointer (ABIArgSlot i64 u64) ABIArg)
(extern extractor abi_arg_struct_pointer abi_arg_struct_pointer)

;; Extractor to detect the special case where a non-struct argument
;; is implicitly passed by reference using a hidden pointer.
(decl abi_arg_implicit_pointer (ABIArgSlot i64 Type) ABIArg)
(extern extractor abi_arg_implicit_pointer abi_arg_implicit_pointer)

;; Convert a real register number into a virtual register.
(decl real_reg_to_reg (RealReg) Reg)
(extern constructor real_reg_to_reg real_reg_to_reg)

;; Convert a real register number into a writable virtual register.
(decl real_reg_to_writable_reg (RealReg) WritableReg)
(extern constructor real_reg_to_writable_reg real_reg_to_writable_reg)

;; Generate a move between two registers.
(decl gen_move (Type WritableReg Reg) MInst)
(extern constructor gen_move gen_move)

;; Copy a return value to a set of registers.
(decl copy_to_regs (WritableValueRegs Value) Unit)
(rule (copy_to_regs dsts val @ (value_type ty))
      (let ((srcs ValueRegs (put_in_regs val)))
        (copy_to_regs_range ty (value_regs_range srcs) dsts srcs)))

;; Helper for `copy_to_regs` that uses a range to index into the reg/value
;; vectors. Fails for the empty range.
(decl copy_to_regs_range (Type Range WritableValueRegs ValueRegs) Unit)

(rule (copy_to_regs_range ty (range_singleton idx) dsts srcs)
      (let ((dst WritableReg (writable_regs_get dsts idx))
            (src Reg (value_regs_get srcs idx)))
        (emit (gen_move ty dst src))))

(rule (copy_to_regs_range ty (range_unwrap head tail) dsts srcs)
      (let ((dst WritableReg (writable_regs_get dsts head))
            (src Reg (value_regs_get srcs head))
            (_ Unit (emit (gen_move ty dst src))))
        (copy_to_regs_range ty tail dsts srcs)))

(decl lower_return (Range ValueSlice) InstOutput)
(rule (lower_return (range_empty) _) (output_none))
(rule (lower_return (range_unwrap head tail) args)
      (let ((_ Unit (copy_to_regs (retval head) (value_slice_get args head))))
        (lower_return tail args)))

;;;; Automatic conversions ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

(convert Inst Value def_inst)
(convert Reg ValueRegs value_reg)
(convert Value Reg put_in_reg)
(convert Value ValueRegs put_in_regs)
(convert WritableReg Reg writable_reg_to_reg)
(convert ValueRegs InstOutput output)
(convert Reg InstOutput output_reg)
(convert Value InstOutput output_value)
(convert Offset32 u32 offset32_to_u32)
(convert ExternalName BoxExternalName box_external_name)
(convert PReg Reg preg_to_reg)