From a33bf774077393372f6a9c47c8c0fc7e113aec70 Mon Sep 17 00:00:00 2001
From: Enrico Lumetti <enrico.lumetti@gmail.com>
Date: Mon, 15 Aug 2022 01:56:24 +0200
Subject: [PATCH] Instruction selection: basic bril->AArch64Var conversion

---
 aarch64var.rkt              | 25 +++++++++++++++++++++++
 complete-tests.rkt          |  6 +++++-
 select-instr.rkt            | 33 ++++++++++++++++++++++++++++++
 tests/all-tests.rkt         |  4 +++-
 tests/test-select-instr.rkt | 40 +++++++++++++++++++++++++++++++++++++
 5 files changed, 106 insertions(+), 2 deletions(-)
 create mode 100644 aarch64var.rkt
 create mode 100644 select-instr.rkt
 create mode 100644 tests/test-select-instr.rkt

diff --git a/aarch64var.rkt b/aarch64var.rkt
new file mode 100644
index 0000000..a5349d4
--- /dev/null
+++ b/aarch64var.rkt
@@ -0,0 +1,25 @@
+#lang racket
+
+(provide Label Var Reg Imm LMov Add Sub RetDefault Svc Bl)
+
+(require racket/struct)
+
+(struct AArch64VarProgram (info labeled-seq) #:transparent)
+(struct Label (label) #:transparent)
+(struct Var (var-name) #:transparent)
+(struct Reg (reg-name) #:transparent)
+(struct Imm (immediate) #:transparent)
+(struct LMov (src dest) #:transparent)
+(struct Add (op1 op2 dest) #:transparent)
+(struct Sub (op1 op2 dest) #:transparent)
+(struct RetDefault () #:transparent)
+(struct Svc (i) #:transparent)
+(struct Bl (label) #:transparent)
+
+(define valid-reg-names
+  '(x0 x1 x2 x3 x4 x5 x6
+    x7 x8 x9 x10 x11 x12
+    x13 x14 x15 x16 x17 x18
+    x19 x20 x21 x22 x23 x24
+    x25 x26 x27 x28 x29 x30
+    sp pc xzr))
diff --git a/complete-tests.rkt b/complete-tests.rkt
index 56a2e35..af89abb 100644
--- a/complete-tests.rkt
+++ b/complete-tests.rkt
@@ -46,7 +46,11 @@
   (test-suite
    "Complete Tests"
    (complete-rvar-test
-     "Simple RVar Tests"
+     "Simple addition"
+     "complete-tests/test0.rvar"
+     "complete-tests/test0.bril")
+   (complete-rvar-test
+     "Simple addition with subexpression"
      "complete-tests/test1.rvar"
      "complete-tests/test1.bril")))
     
diff --git a/select-instr.rkt b/select-instr.rkt
new file mode 100644
index 0000000..ed00825
--- /dev/null
+++ b/select-instr.rkt
@@ -0,0 +1,33 @@
+#lang racket
+
+(require (prefix-in bril: bril/lang))
+(require "aarch64var.rkt")
+
+; only deals with int64 type!
+(define (bril-instr-to-aarch64var bril-instr)
+  (match bril-instr
+   [(bril:Label label) (Label label)]
+   [(bril:ConstantInstr dest-name _ (bril:Int const-val))
+    (list (LMov (Imm const-val) (Var dest-name)))]
+   [(bril:ValueInstr op dest type args _ _)
+    (bril-value-instr-to-aarch64 op dest args)]
+   [(bril:EffectInstr op args _ _)
+    (match op
+     ['return (bril-return-to-aarch64var args)])]))
+
+(define (bril-value-instr-to-aarch64 op dest args)
+  (case op
+    ['add (list (Add (Var (list-ref args 0))
+                     (Var (list-ref args 1))
+                     (Var dest)))]
+    ['sub (list (Sub (Var (list-ref args 0))
+                     (Var (list-ref args 1))
+                     (Var dest)))]))
+
+(define (bril-return-to-aarch64var args)
+  (match args
+    [(list var)
+     (list (LMov (Reg 'x0) (Var (list-ref args 0)))
+           (RetDefault))]
+    [_ (list (RetDefault))]))
+       
diff --git a/tests/all-tests.rkt b/tests/all-tests.rkt
index 6eb575e..a43900e 100644
--- a/tests/all-tests.rkt
+++ b/tests/all-tests.rkt
@@ -10,6 +10,7 @@
 ;(require "test-remove-complex-opera.rkt")
 ;(require "test-explicate-control.rkt")
 (require "test-cvar-to-bril.rkt")
+(require "test-select-instr.rkt")
 
 (define all-tests
   (test-suite
@@ -20,5 +21,6 @@
    uniquify-tests
    ;remove-complex-opera-tests
    ;explicate-control-tests
-   cvar-to-bril-tests))
+   cvar-to-bril-tests
+   select-instr-tests))
    
diff --git a/tests/test-select-instr.rkt b/tests/test-select-instr.rkt
new file mode 100644
index 0000000..8cadb2f
--- /dev/null
+++ b/tests/test-select-instr.rkt
@@ -0,0 +1,40 @@
+#lang racket
+
+(provide select-instr-tests)
+
+(require rackunit)
+
+(require (prefix-in bril: bril/lang))
+(require "../aarch64var.rkt")
+(require/expose "../select-instr.rkt" (bril-instr-to-aarch64var))
+
+(define bril-label (bril:Label "main"))
+(define bril-add
+  (bril:ValueInstr 'add "a" (bril:Type 'int) '("c" "d") '() '()))
+(define bril-const
+  (bril:ConstantInstr "a" (bril:Type 'int) (bril:Int 21)))
+(define bril-return
+  (bril:EffectInstr 'return '("x") '() '()))
+
+(define select-instr-tests
+  (test-suite
+   "Instruction Selection Tests"
+   (test-suite
+     "Single instruction selection"
+     (test-case
+       "Label"
+       (check-equal? (bril-instr-to-aarch64var bril-label)
+                     (Label "main")))
+     (test-case
+       "Addition"
+       (check-equal? (bril-instr-to-aarch64var bril-add)
+                     (list (Add (Var "c") (Var "d") (Var "a")))))
+     (test-case
+       "Constant Instr"
+       (check-equal? (bril-instr-to-aarch64var bril-const)
+                     (list (LMov (Imm 21) (Var "a")))))
+     (test-case
+       "Return"
+       (check-equal? (bril-instr-to-aarch64var bril-return)
+                     (list (LMov (Reg 'x0) (Var "x"))
+                           (RetDefault)))))))