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Simplify LowerBackend interface (#5432)

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* Refactor lower_branch to have Unit result

Branches cannot have any output, so it is more straightforward
to have the ISLE term return Unit instead of InstOutput.

Also provide a new `emit_side_effect` term to simplify
implementation of `lower_branch` rules with Unit result.

* Simplify LowerBackend interface

Move all remaining asserts from the LowerBackend::lower and
::lower_branch_group into the common call site.

Change return value of ::lower to Option<InstOutput>, and
return value of ::lower_branch_group to Option<()> to match
ISLE term signature.

Only pass the first branch into ::lower_branch_group and
rename it to ::lower_branch.

As a result of all those changes, LowerBackend routines
now consists solely to calls to the corresponding ISLE
routines.
This commit is contained in:
Ulrich Weigand
2022-12-14 01:48:25 +01:00
committed by GitHub
parent 299be327d5
commit f0af622208
16 changed files with 133 additions and 244 deletions
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30
cranelift/codegen/src/isa/x64/lower.isle
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@@ -7,7 +7,7 @@
;; A variant of the main lowering constructor term, used for branches.
;; The only difference is that it gets an extra argument holding a vector
;; of branch targets to be used.
(decl partial lower_branch (Inst MachLabelSlice) InstOutput)
(decl partial lower_branch (Inst MachLabelSlice) Unit)
;;;; Rules for `iconst` ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
@@ -2865,55 +2865,55 @@
;; Rules for `jump` ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(rule (lower_branch (jump _ _) (single_target target))
(side_effect (jmp_known target)))
(emit_side_effect (jmp_known target)))
;; Rules for `brz` and `brnz` ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(rule 2 (lower_branch (brz (icmp cc a b) _ _) (two_targets taken not_taken))
(let ((cmp IcmpCondResult (invert_icmp_cond_result (emit_cmp cc a b))))
(side_effect (jmp_cond_icmp cmp taken not_taken))))
(emit_side_effect (jmp_cond_icmp cmp taken not_taken))))
(rule 2 (lower_branch (brz (uextend (icmp cc a b)) _ _) (two_targets taken not_taken))
(let ((cmp IcmpCondResult (invert_icmp_cond_result (emit_cmp cc a b))))
(side_effect (jmp_cond_icmp cmp taken not_taken))))
(emit_side_effect (jmp_cond_icmp cmp taken not_taken))))
(rule 2 (lower_branch (brz (fcmp cc a b) _ _) (two_targets taken not_taken))
(let ((cmp FcmpCondResult (emit_fcmp (floatcc_inverse cc) a b)))
(side_effect (jmp_cond_fcmp cmp taken not_taken))))
(emit_side_effect (jmp_cond_fcmp cmp taken not_taken))))
(rule 2 (lower_branch (brz (uextend (fcmp cc a b)) _ _) (two_targets taken not_taken))
(let ((cmp FcmpCondResult (emit_fcmp (floatcc_inverse cc) a b)))
(side_effect (jmp_cond_fcmp cmp taken not_taken))))
(emit_side_effect (jmp_cond_fcmp cmp taken not_taken))))
(rule 1 (lower_branch (brz val @ (value_type $I128) _ _) (two_targets taken not_taken))
(side_effect (jmp_cond_icmp (cmp_zero_i128 (CC.NZ) val) taken not_taken)))
(emit_side_effect (jmp_cond_icmp (cmp_zero_i128 (CC.NZ) val) taken not_taken)))
(rule 0 (lower_branch (brz val @ (value_type (ty_int_bool_or_ref)) _ _) (two_targets taken not_taken))
(side_effect
(emit_side_effect
(with_flags_side_effect (cmp_zero_int_bool_ref val)
(jmp_cond (CC.Z) taken not_taken))))
(rule 2 (lower_branch (brnz (icmp cc a b) _ _) (two_targets taken not_taken))
(side_effect (jmp_cond_icmp (emit_cmp cc a b) taken not_taken)))
(emit_side_effect (jmp_cond_icmp (emit_cmp cc a b) taken not_taken)))
(rule 2 (lower_branch (brnz (fcmp cc a b) _ _) (two_targets taken not_taken))
(let ((cmp FcmpCondResult (emit_fcmp cc a b)))
(side_effect (jmp_cond_fcmp cmp taken not_taken))))
(emit_side_effect (jmp_cond_fcmp cmp taken not_taken))))
(rule 2 (lower_branch (brnz (uextend (icmp cc a b)) _ _) (two_targets taken not_taken))
(side_effect (jmp_cond_icmp (emit_cmp cc a b) taken not_taken)))
(emit_side_effect (jmp_cond_icmp (emit_cmp cc a b) taken not_taken)))
(rule 2 (lower_branch (brnz (uextend (fcmp cc a b)) _ _) (two_targets taken not_taken))
(let ((cmp FcmpCondResult (emit_fcmp cc a b)))
(side_effect (jmp_cond_fcmp cmp taken not_taken))))
(emit_side_effect (jmp_cond_fcmp cmp taken not_taken))))
(rule 1 (lower_branch (brnz val @ (value_type $I128) _ _) (two_targets taken not_taken))
(side_effect (jmp_cond_icmp (cmp_zero_i128 (CC.Z) val) taken not_taken)))
(emit_side_effect (jmp_cond_icmp (cmp_zero_i128 (CC.Z) val) taken not_taken)))
(rule 0 (lower_branch (brnz val @ (value_type (ty_int_bool_or_ref)) _ _) (two_targets taken not_taken))
(side_effect
(emit_side_effect
(with_flags_side_effect (cmp_zero_int_bool_ref val)
(jmp_cond (CC.NZ) taken not_taken))))
@@ -2944,7 +2944,7 @@
;; Rules for `br_table` ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(rule (lower_branch (br_table idx @ (value_type ty) _ _) (jump_table_targets default_target jt_targets))
(side_effect (jmp_table_seq ty idx default_target jt_targets)))
(emit_side_effect (jmp_table_seq ty idx default_target jt_targets)))
;; Rules for `select_spectre_guard` ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;