Add initial compiler implementation

1 files changed, 87 insertions, 0 deletions

diff --git a/src/cljcc/compiler.clj b/src/cljcc/compiler.clj
new file mode 100644
index 0000000..6a4d13d
--- /dev/null
+++ b/src/cljcc/compiler.clj
@@ -0,0 +1,87 @@
+(ns cljcc.compiler
+  (:require [cljcc.parser :as p]
+            [instaparse.core :as insta]
+            [clojure.edn :as edn]
+            [cljcc.util :refer [get-os]]
+            [clojure.string :as str]))
+
+(defn transform-function [return-type identifier args body]
+  {:op :function
+   :identifier identifier
+   :args args
+   :body body})
+
+(defn ast->compile [ast]
+ (insta/transform
+  {:function transform-function
+   :identifier str
+   :constant (comp edn/read-string str)
+   :exp (fn [v]
+          {:op :movl
+           :src v
+           :dst :eax})
+    :statement (fn [_ v]
+                 [v {:op :ret}])}
+  ast))
+
+(defn handle-function-name [name]
+  (if (= :mac (get-os))
+    (str "_" name)
+    name))
+
+(defn emit-instruction
+  ([inst]
+   (str "    " (symbol inst)))
+  ([inst src dst]
+   (str "    " (symbol inst) "    " "$" src ", %" (symbol dst))))
+
+(defn statement-fn [stmt]
+  (condp = (:op stmt)
+        :ret (emit-instruction :ret)
+        :movl (emit-instruction (:op stmt) (:src stmt) (:dst stmt))))
+
+(statement-fn {:op :movl :src 1 :dst :eax})
+
+(defn emit-function-assembly [fn-ast]
+  (let [name (handle-function-name (:identifier fn-ast))
+        globl-line (str "    .globl " name)
+        fn-start-line (str name ":")
+        body-statements (map statement-fn (:body fn-ast))]
+    (flatten [globl-line fn-start-line body-statements])))
+
+(def linux-assembly-end ".section .note.GNU-stack,\"\",@progbits")
+
+(defn il->assembly [il]
+  (let [fn-assembly (emit-function-assembly (first il))]
+    (if (= :linux (get-os))
+      (conj fn-assembly linux-assembly-end)
+      fn-assembly)))
+
+(defn join-assembly [assembly-lines]
+  (str/join "\n" assembly-lines))
+
+(defn run-compile [source]
+  (-> source
+      p/parse
+      ast->compile
+      il->assembly
+      join-assembly))
+
+(comment
+
+ (def ex "int main(void) {return 2;}")
+
+ (-> ex
+      p/parse)
+
+ (-> ex
+      p/parse
+      ast->compile)
+
+ (-> ex
+   p/parse
+   ast->compile
+   il->assembly
+   join-assembly)
+
+ ,)