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|
(ns cljcc.analyzer
(:require [cljcc.lexer :as l]
[clojure.pprint :as pp]
[cljcc.util :as u]
[cljcc.parser :as p]))
(defn- unique-identifier
([] (unique-identifier "analyzer"))
([identifier] (u/create-identifier! identifier)))
(declare resolve-block)
(defn- resolve-exp [e mp]
(condp = (:exp-type e)
:constant-exp e
:variable-exp (if (contains? mp (:identifier e))
(p/variable-exp-node (:name (get mp (:identifier e))))
(throw (ex-info "Undeclared variable seen." {:variable e})))
:assignment-exp (let [left (:left e)
right (:right e)
op (:assignment-operator e)
left-var? (= :variable-exp (:exp-type left))]
(if left-var?
(p/assignment-exp-node (resolve-exp left mp)
(resolve-exp right mp)
op)
(throw (ex-info "Invalid lvalue." {:lvalue e}))))
:binary-exp (p/binary-exp-node (resolve-exp (:left e) mp)
(resolve-exp (:right e) mp)
(:binary-operator e))
:unary-exp (p/unary-exp-node (:unary-operator e) (resolve-exp (:value e) mp))
:conditional-exp (p/conditional-exp-node (resolve-exp (:left e) mp)
(resolve-exp (:middle e) mp)
(resolve-exp (:right e) mp))
(throw (ex-info "Analyzer error. Invalid expression type" {:exp e}))))
(defn- resolve-optional-exp [e var-mp]
(if (nil? e)
e
(resolve-exp e var-mp)))
(defn- resolve-declaration [d mp]
(if (and (contains? mp (:identifier d)) (:from-current-block (get mp (:identifier d))))
(throw (ex-info "Analyzer error. Duplicate variable declaration." {:declaration d}))
(let [ident (:identifier d)
unique-name (unique-identifier ident)
updated-mp (assoc mp ident {:name unique-name
:from-current-block true})
init (when (:initial d) (resolve-exp (:initial d) updated-mp))]
(if init
{:declaration (p/declaration-node unique-name init)
:variable-map updated-mp}
{:declaration (p/declaration-node unique-name)
:variable-map updated-mp}))))
(defn- copy-variable-map [var-mp]
(zipmap (keys var-mp)
(map (fn [m]
(update m :from-current-block (fn [_] false)))
(vals var-mp))))
(defn- resolve-for-init [for-init var-mp]
(if (= (:type for-init) :declaration)
(resolve-declaration for-init var-mp)
(resolve-optional-exp for-init var-mp)))
(defn- resolve-statement [s mp]
(condp = (:statement-type s)
:return (p/return-statement-node (resolve-exp (:value s) mp))
:expression (p/expression-statement-node (resolve-exp (:value s) mp))
:if (if (:else-statement s)
(p/if-statement-node (resolve-exp (:condition s) mp)
(resolve-statement (:then-statement s) mp)
(resolve-statement (:else-statement s) mp))
(p/if-statement-node (resolve-exp (:condition s) mp)
(resolve-statement (:then-statement s) mp)))
:break s
:continue s
:while (p/while-statement-node (resolve-exp (:condition s) mp)
(resolve-statement (:body s) mp))
:do-while (p/do-while-statement-node (resolve-exp (:condition s) mp)
(resolve-statement (:body s) mp))
:for (let [new-var-map (copy-variable-map mp)
for-init (resolve-for-init (:init s) new-var-map)
new-var-map (if (:declaration for-init)
(:variable-map for-init)
new-var-map) ; updates new-var-map so that include possible
; variable declaration
condition (resolve-optional-exp (:condition s) new-var-map)
post (resolve-optional-exp (:post s) new-var-map)
body (resolve-statement (:body s) new-var-map)]
(p/for-statement-node for-init condition post body))
:compound (let [updated-mp (copy-variable-map mp)]
(p/compound-statement-node (:block (resolve-block (:block s) updated-mp))))
:empty (p/empty-statement-node)
(throw (ex-info "Analyzer error. Invalid statement." {:statement s}))))
(defn- resolve-block-item [item mp]
(let [type (:type item)]
(cond
(= type :declaration) (let [v (resolve-declaration item mp)]
{:block-item (:declaration v)
:variable-map (:variable-map v)})
(= type :statement) {:block-item (resolve-statement item mp)
:variable-map mp}
:else (throw (ex-info "Analyzer Error. Invalid statement/declaration." {item item})))))
(defn- resolve-block
([block]
(resolve-block block {}))
([block var-mp]
(reduce (fn [acc block-item]
(let [v (resolve-block-item block-item (:variable-map acc))]
{:block (conj (:block acc) (:block-item v))
:variable-map (:variable-map v)}))
{:block []
:variable-map var-mp}
block)))
(defn- annotate-label [n l]
(assoc n :label l))
(defn- label-statement
([s]
(label-statement s nil))
([s current-label]
(let [s-type (:statement-type s)]
(cond
(= s-type :break) (if (nil? current-label)
(throw (ex-info "break statement outside of loop" {}))
(p/break-statement-node current-label))
(= s-type :continue) (if (nil? current-label)
(throw (ex-info "continue statement outside of loop" {}))
(p/continue-statement-node current-label))
(= s-type :while) (let [new-label (unique-identifier "while_label")
l-body (label-statement (:body s) new-label)
l-while (p/while-statement-node (:condition s) l-body)]
(annotate-label l-while new-label))
(= s-type :do-while) (let [new-label (unique-identifier "do_while_label")
l-body (label-statement (:body s) new-label)
l-do-while (p/do-while-statement-node (:condition s) l-body)]
(annotate-label l-do-while new-label))
(= s-type :for) (let [new-label (unique-identifier "for_label")
l-body (label-statement (:body s) new-label)
l-for (p/for-statement-node (:init s) (:condition s) (:post s) l-body)]
(annotate-label l-for new-label))
(= s-type :if) (if (:else-statement s)
(p/if-statement-node (:condition s)
(label-statement (:then-statement s) current-label)
(label-statement (:else-statement s) current-label))
(p/if-statement-node (:condition s)
(label-statement (:then-statement s) current-label)))
(= s-type :compound) (let [update-block-f (fn [item]
(if (= (:type item) :statement)
(label-statement item current-label)
item))
new-block (map update-block-f (:block s))]
(p/compound-statement-node new-block))
(= s-type :return) s
(= s-type :expression) s
(= s-type :empty) s
:else (throw (ex-info "invalid statement reached during loop labelling." {}))))))
(defn- resolve-loop-labels [body]
(let [f (fn [item]
(if (= :statement (:type item))
(label-statement item)
item))
new-body (map f body)]
new-body))
(defn- validate-function [f]
(let [body (resolve-loop-labels (:block (resolve-block (:body f))))]
(assoc f :body body)))
(comment
(resolve-block
[{:type :declaration
:identifier "a",
:initial {:type :exp, :exp-type :constant-exp, :value 1}}
{:type :statement,
:statement-type :return,
:value {:type :exp, :exp-type :constant-exp, :value 0}}])
())
(defn validate [ast]
(map validate-function ast))
(defn- validate-from-src [s]
(u/reset-counter!)
(-> s
l/lex
p/parse
validate))
(comment
(pp/pprint
(validate-from-src
"int main (void) {
int a = 3;
{
int a = a = 4;
}
while (a < 10) {
break;
}
return a;
}"))
(pp/pprint
(validate-from-src
"int main (void) {
int x = 1 + x;
}"))
())
|
