From 1cde4765bcd76ceefffbe22bf6d097c8a9a7144a Mon Sep 17 00:00:00 2001
From: Michael Schwarz <michael.schwarz93@gmail.com>
Date: Thu, 16 Jan 2020 13:18:46 +0100
Subject: [PATCH] Add support for __imag__ References #8, References #9

---
 src/check.ml              | 7 ++++---
 src/cil.ml                | 8 ++++----
 src/cil.mli               | 4 ++--
 src/frontc/cabs2cil.ml    | 7 +++++--
 test/small1/c99-complex.c | 6 ++++++
 5 files changed, 21 insertions(+), 11 deletions(-)

diff --git a/src/check.ml b/src/check.ml
index 12eba9005..22049f443 100644
--- a/src/check.ml
+++ b/src/check.ml
@@ -500,9 +500,10 @@ and checkExp (isconst: bool) (e: exp) : typ =
 
       | Real e ->
           let te = checkExp isconst e in
-          typeOfReal te
-      | Imag e -> E.s (E.bug "unimplemented")
-
+          typeOfRealAndImagComponents te
+      | Imag e ->
+          let te = checkExp isconst e in
+          typeOfRealAndImagComponents te
       | AlignOf(t) -> begin
           (* Sizeof cannot be applied to certain types *)
           checkType t CTSizeof;
diff --git a/src/cil.ml b/src/cil.ml
index c14a95b84..59180456a 100755
--- a/src/cil.ml
+++ b/src/cil.ml
@@ -1597,8 +1597,8 @@ let isVoidPtrType t =
     TPtr(tau,_) when isVoidType tau -> true
   | _ -> false
 
-(* get the typ of __real__(e) for e of typ t*)
-let typeOfReal t =
+(* get the typ of __real__(e) or __imag__(e) for e of typ t*)
+let typeOfRealAndImagComponents t =
   match unrollType t with
   | TInt _ -> t
   | TFloat (fkind, attrs) ->
@@ -1920,8 +1920,8 @@ let rec typeOf (e: exp) : typ =
   | Const(CReal (_, fk, _)) -> TFloat(fk, [])
 
   | Const(CEnum(tag, _, ei)) -> typeOf tag
-  | Real e -> typeOfReal @@ typeOf e
-  | Imag e -> E.s (E.bug "unsupported")
+  | Real e -> typeOfRealAndImagComponents @@ typeOf e
+  | Imag e -> typeOfRealAndImagComponents @@ typeOf e
   | Lval(lv) -> typeOfLval lv
   | SizeOf _ | SizeOfE _ | SizeOfStr _ -> !typeOfSizeOf
   | AlignOf _ | AlignOfE _ -> !typeOfSizeOf
diff --git a/src/cil.mli b/src/cil.mli
index b7a1aa7ee..8e453049b 100644
--- a/src/cil.mli
+++ b/src/cil.mli
@@ -1324,8 +1324,8 @@ val isVoidType: typ -> bool
 (** is the given type "void *"? *)
 val isVoidPtrType: typ -> bool
 
-(** for numerical __complex types return type of corresponding real part *)
-val typeOfReal: typ -> typ
+(** for numerical __complex types return type of corresponding real part and imaginary parts *)
+val typeOfRealAndImagComponents: typ -> typ
 
 (** for an fkind, return the corresponding complex fkind *)
 val getComplexFkind: fkind -> fkind
diff --git a/src/frontc/cabs2cil.ml b/src/frontc/cabs2cil.ml
index c18982873..de36604de 100644
--- a/src/frontc/cabs2cil.ml
+++ b/src/frontc/cabs2cil.ml
@@ -3658,8 +3658,11 @@ and doExp (asconst: bool)   (* This expression is used as a constant *)
     | A.REAL e ->
       let (se, e', t) = doExp false e (AExp None) in
       let real = Real e' in
-      finishExp se real (typeOfReal t)
-    | A.IMAG e -> E.s (bug "cabs2cil: unsupported")
+      finishExp se real (typeOfRealAndImagComponents t)
+    | A.IMAG e ->
+      let (se, e', t) = doExp false e (AExp None) in
+      let imag = Imag e' in
+      finishExp se imag (typeOfRealAndImagComponents t)
     | A.CLASSIFYTYPE e ->
       let classify_type t =
         match unrollTypeDeep t with (* See gcc/typeclass.h *)
diff --git a/test/small1/c99-complex.c b/test/small1/c99-complex.c
index fdc6a7071..85ae7f4e4 100644
--- a/test/small1/c99-complex.c
+++ b/test/small1/c99-complex.c
@@ -29,10 +29,16 @@ int main(void)
     }
 
     double d = creal(x1);
+    double i = cimag(x1);
+
+    double j = __imag__(1.0if);
 
     if(d != 0.5)
         E(2);
 
+    if(i != 1.0 || j != 1.0)
+        E(3);
+
     double complex z1 = 1.0iF + 1;
     printf("I * I = %.1f%+.1fi\n", creal(z1), cimag(z1));