Assembly generation for trivial programs

4 files changed, 112 insertions, 10 deletions

diff --git a/src/modules/ast/assembly-tree.scm b/src/modules/ast/assembly-tree.scm
new file mode 100644
index 0000000..ee3e116
--- /dev/null
+++ b/src/modules/ast/assembly-tree.scm
@@ -0,0 +1,25 @@
+(define-module (modules ast assembly-tree)
+  #:use-module (srfi srfi-9)
+  #:export (make-subroutine
+            subroutine?
+            subroutine-label
+            subroutine-instructions
+
+            make-instruction
+            instruction?
+            instruction-operator
+            instruction-operand-1
+            instruction-operand-2))
+
+(define-record-type <subroutine>
+  (make-subroutine label instrs)
+  subroutine?
+  (label subroutine-label)
+  (instrs subroutine-instructions))
+
+(define-record-type <instruction>
+  (make-instruction op oper1 oper2)
+  instruction?
+  (op instruction-operator)
+  (oper1 instruction-operand-1)
+  (oper2 instruction-operand-2))
diff --git a/src/modules/ast/syntax-tree.scm b/src/modules/ast/syntax-tree.scm
new file mode 100644
index 0000000..738b115
--- /dev/null
+++ b/src/modules/ast/syntax-tree.scm
@@ -0,0 +1,48 @@
+(define-module (modules ast syntax-tree)
+  #:use-module (srfi srfi-9)
+  #:export (make-program
+            program?
+            program-function
+
+            make-function
+            function?
+            function-id
+            function-stmt
+
+            make-stmt
+            stmt?
+            stmt-expr
+
+            make-expr
+            expr?
+            expr-int
+
+            make-id
+            id?
+            id-symbol))
+
+(define-record-type <program>
+  (make-program func)
+  program?
+  (func program-function))
+
+(define-record-type <function>
+  (make-function id stmt)
+  function?
+  (id function-id)
+  (stmt function-stmt))
+
+(define-record-type <stmt>
+  (make-stmt expr)
+  stmt?
+  (expr stmt-expr))
+
+(define-record-type <expr>
+  (make-expr int)
+  expr?
+  (int expr-int))
+
+(define-record-type <id>
+  (make-id symbol)
+  id?
+  (symbol id-symbol))
diff --git a/src/modules/generator/generator.scm b/src/modules/generator/generator.scm
new file mode 100644
index 0000000..4c08e32
--- /dev/null
+++ b/src/modules/generator/generator.scm
@@ -0,0 +1,31 @@
+(define-module (modules generator generator)
+  #:use-module (modules ast syntax-tree)
+  #:use-module (modules ast assembly-tree)
+  #:export (generate))
+
+(define (generate node)
+  (cond
+   ((program? node) (g-program node))
+   ((function? node) (g-function node))
+   ((stmt? node) (g-stmt node))
+   ((expr? node) (g-expr node))
+   ((id? node) (g-id node))
+   (else (error "Unknown AST element"))))
+
+(define (g-program p)
+  (make-program (generate (program-function p))))
+
+(define (g-function f)
+  (make-subroutine (generate (function-id f))
+                   (generate (function-stmt f))))
+
+(define (g-stmt s)
+  (generate (stmt-expr s)))
+
+(define (g-expr e)
+  ;; for now, we assume only 'return'!
+  (list (make-instruction "mov1" "%eax" "$2")
+        (make-instruction "ret" #f #f)))
+
+(define (g-id i)
+  (id-symbol i))
diff --git a/src/modules/parser/parser.scm b/src/modules/parser/parser.scm
index e70a825..ceac389 100644
--- a/src/modules/parser/parser.scm
+++ b/src/modules/parser/parser.scm
@@ -1,34 +1,32 @@
 (define-module (modules parser parser)
   #:use-module (ice-9 match)
+  #:use-module (modules ast syntax-tree)
   #:export (p-program))
 
 
 (define (die)
   (error "syntax error"))
 
-
 (define (p-program tokens)
   (match tokens
     ((func ...)
-     `(program ,(p-function func)))
+     (make-program (p-function func)))
     (_ (die))))
 
 (define (p-function tokens)
   (match tokens
     (('int (? string? id) 'left-paren 'void 'right-paren 'open-brace stmt ... 'close-brace)
-     `(function (identifier ,id) ,(p-statement stmt)))
+     (make-function (make-id id) (p-stmt stmt)))
     (_ (die))))
 
-(define (p-statement tokens)
+(define (p-stmt tokens)
   (match tokens
     (`(return ,expr semi-colon)
-     `(return ,(p-exp (list expr))))
+     (make-stmt (p-expr (list expr))))
     (_ (die))))
 
-(define (p-exp tokens)
-  "Matches any list containing a single number,
-"
+(define (p-expr tokens)
   (match tokens
-    (((? number? const))
-     `(constant ,const))
+    (((? number? int))
+     (make-expr int))
     (_ (die))))