Stack zeroization for ARM: add tests

Co-authored-by: Santiago Arranz Olmos <santiago.arranz1@gmail.com>

compiler/Makefile

@@ -15,7 +15,9 @@ CHECKCATS ?= \
 	arm-m4 \
 	arm-m4-print \
 	x86-64-stack-zero-loop \
-	x86-64-stack-zero-unrolled
+	x86-64-stack-zero-unrolled \
+	arm-m4-stack-zero-loop \
+	arm-m4-stack-zero-unrolled
 
 # --------------------------------------------------------------------
 DESTDIR  ?=

compiler/config/tests.config

@@ -67,3 +67,15 @@ args    = -stack-zero=unrolled
 okdirs  = examples/**/x86-64 tests/success/**/x86-64
 kodirs  = tests/fail/**/x86-64
 exclude = !tests/fail/warning
+
+[test-arm-m4-stack-zero-loop]
+bin     = ./scripts/check-arm-m4
+args    = -stack-zero=loop
+okdirs  = examples/**/arm-m4 tests/success/**/arm-m4
+kodirs  = tests/fail/**/arm-m4
+
+[test-arm-m4-stack-zero-unrolled]
+bin     = ./scripts/check-arm-m4
+args    = -stack-zero=unrolled
+okdirs  = examples/**/arm-m4 tests/success/**/arm-m4
+kodirs  = tests/fail/**/arm-m4

compiler/src/pretyping.ml

@@ -1875,11 +1875,10 @@ let process_f_annot loc funname f_cc annot =
     match strategy, size with
     | None, None -> None
     | None, Some _ ->
-        hierror
-          ~loc:(Lone loc)
-          ~funname
-          ~kind:"unexpected annotation"
-          "\"stackzerosize\" cannot be used alone, you need to specify a strategy with attribute \"stackzero\""
+        warning Always
+          (L.i_loc0 loc)
+          "\"stackzerosize\" is ignored, since you did not specify a strategy with attribute \"stackzero\"";
+        None
     | Some szs, _ -> Some (szs, size)
   in
 

compiler/tests/success/arm-m4/rand.jazz

@@ -1,3 +1,9 @@
+/* stack zeroization uses the alignment of the function as the default clear
+   step size. Due to the system call, the function is aligned on u128, but stack
+   zeroization is not implemented for u128 on ARM. Thus we introduce this
+   annotation to use u32 for the clear step size instead.
+*/
+#[stackzerosize=u32]
 export
 fn random32() -> reg u32 {
   stack u8[4] s;