Add initial compiler implementation

5 files changed, 223 insertions, 23 deletions

diff --git a/src/cljcc/cljcc.clj b/src/cljcc/cljcc.clj
index 1e102af..1da49fd 100644
--- a/src/cljcc/cljcc.clj
+++ b/src/cljcc/cljcc.clj
@@ -1,28 +1,8 @@
 (ns cljcc.cljcc
   (:require
-   [instaparse.core :as insta]
-   [clojure.java.io :as io])
+   [cljcc.driver :as d])
   (:gen-class))
 
-(def ex-prg "int main(void) {return 2;}")
-
-(def whitespace
-  (insta/parser
-   "whitespace = #'\\s+'"))
-
-(def c-parser
-  (insta/parser
-   "<program> = function+
-    function = #'int\\b' identifier <'('> #'void\\b' <')'> <'{'> statement <'}'>
-    statement = #'return\\b' exp <';'>
-    exp = constant
-    identifier = #'[a-zA-Z_]\\w*\\b'
-    constant = #'[0-9]+\\b'
-    keyword = #'int\\b' | #'return\\b' | #'void\\b'"
-   :auto-whitespace whitespace))
-
-(println (c-parser ex-prg))
-
 (defn greet
   "Callable entry point to the application."
   [data]
@@ -31,5 +11,12 @@
 (defn -main
   "I don't do a whole lot ... yet."
   [& args]
-  (let [input-file-path (first args)])
-  (greet {:name (first args)}))
+  (let [input-file-path (first args)]
+    (try
+     (d/run input-file-path)
+     (println "success")
+     (catch Exception e
+       (println "Error: " (.getMessage e))
+       (System/exit 1))
+     (finally
+       (System/exit 0)))))
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)
+
+ ,)
diff --git a/src/cljcc/driver.clj b/src/cljcc/driver.clj
new file mode 100644
index 0000000..960bd1f
--- /dev/null
+++ b/src/cljcc/driver.clj
@@ -0,0 +1,82 @@
+(ns cljcc.driver
+  (:require [clojure.java.shell :refer [sh]]
+            [clojure.java.io :as io]
+            [cljcc.compiler :as c]
+            [cljcc.util :refer [get-os handle-sh mac-aarch64?]]))
+
+(defn make-file-name
+  ([filename ext]
+   (str filename "." ext))
+  ([directory filename ext]
+   (str directory "/" filename "." ext)))
+
+(defn handle-os []
+  (let [os (get-os)]
+    (condp = os
+      :linux (println "running on linux")
+      :mac (if (mac-aarch64?)
+             (println "running on mac arch 64")
+             (println "running on mac"))
+      :unsupported (throw (Exception. (str os " is not currently supported."))))))
+
+(defn remove-extension [filename]
+  (if (.contains filename ".")
+    (.substring filename 0 (.lastIndexOf filename "."))
+    filename))
+
+(defn preprocess [directory filename]
+  (let [input-file-path (make-file-name directory (remove-extension filename) "c")
+        preprocessed-file-path (make-file-name directory (remove-extension filename) "i")
+        output (handle-sh "gcc" "-E" "-P" input-file-path "-o" preprocessed-file-path)]
+    (if (= 1 (:exit output))
+      (throw (Exception. (:out output)))
+      (println (str "Successfully preprocessed file: " preprocessed-file-path)))))
+
+(defn assemble [directory filename]
+  (let [file-without-ext (remove-extension filename)
+        assembly-file (make-file-name directory file-without-ext "s")
+        output-file (str directory "/" file-without-ext)
+        output (handle-sh "gcc" assembly-file "-o" output-file)]
+    (println file-without-ext assembly-file output-file output)
+    (if (= 1 (:exit output))
+      (throw (Exception. (:out output)))
+      (println (str "Successfully created executable at: " output-file output)))))
+
+(defn run-compile [directory filename]
+  (let [preprocessed-file-path (make-file-name directory (remove-extension filename) "i")
+        file (io/file preprocessed-file-path)
+        source (slurp file)
+        assembled-source (c/run-compile source)
+        out-file-path (make-file-name directory (remove-extension filename) "s")]
+    (spit out-file-path assembled-source)
+    (println "succesfully generated .s file" assembled-source)))
+
+(defn cleanup [directory filename]
+  (let [file-without-ext (remove-extension filename)]
+    (sh "rm" (make-file-name directory file-without-ext "i"))
+    (sh "rm" (make-file-name directory file-without-ext "s"))))
+
+(defn run
+  "Runs the compiler driver with the given input source file."
+  [file-path]
+  (let [file (io/file file-path)
+        filename (.getName file)
+        directory (.getParent file)]
+    (handle-os)
+    (preprocess directory filename)
+    (run-compile directory filename)
+    (assemble directory filename)
+    (cleanup directory filename)
+    (println "Successfully created executable at " directory " for filename " filename)))
+
+(comment
+
+ (run "/Users/shagunagrawal/Development/c_tests/ex2.c")
+
+ (assemble "/Users/shagunagrawal/Development/c_tests" "ex2.c")
+
+ (handle-sh "gcc" "-E" "-P" "/Users/shagunagrawal/Development/c_tests/ex2.c" "-o" "/Users/shagunagrawal/Development/c_tests/out.i")
+
+ (sh "gcc" "-E" "-P" "/Users/shagunagrawal/Development/c_tests/ex1.c" "-o" "/Users/shagunagrawal/Development/c_tests/out.i")
+
+ ,)
diff --git a/src/cljcc/parser.clj b/src/cljcc/parser.clj
new file mode 100644
index 0000000..3c54012
--- /dev/null
+++ b/src/cljcc/parser.clj
@@ -0,0 +1,25 @@
+(ns cljcc.parser
+  (:require
+   [instaparse.core :as insta]))
+
+(def whitespace
+  (insta/parser
+   "whitespace = #'\\s+'"))
+
+(def c-parser
+  (insta/parser
+   "<program> = function+
+    function = #'int\\b' identifier <'('> #'void\\b' <')'> <'{'> statement <'}'>
+    statement = #'return\\b' exp <';'>
+    exp = constant
+    identifier = #'[a-zA-Z_]\\w*\\b'
+    constant = #'[0-9]+\\b'
+    keyword = #'int\\b' | #'return\\b' | #'void\\b'"
+   :auto-whitespace whitespace))
+
+(defn parse [source]
+  (c-parser source))
+
+(comment
+ (parse "int main(void) {return 2;}")
+ ,)
diff --git a/src/cljcc/util.clj b/src/cljcc/util.clj
new file mode 100644
index 0000000..1087029
--- /dev/null
+++ b/src/cljcc/util.clj
@@ -0,0 +1,19 @@
+(ns cljcc.util
+  (:require [clojure.java.shell :refer [sh]]))
+
+(defn get-os []
+  (let [os-name (.toLowerCase (System/getProperty "os.name"))]
+    (cond
+      (.contains os-name "mac") :mac
+      (.contains os-name "linux") :linux
+      :else :unsupported)))
+
+(defn mac-aarch64? []
+  (and (= :mac (get-os)) (= (System/getProperty "os.arch" "aarch64"))))
+
+(defn handle-sh
+  "Preprends arch -x86_64 if running under Mac M chips."
+  [command & args]
+  (if (mac-aarch64?)
+    (apply sh "arch" "-x86_64" command args)
+    (apply sh command args)))