Limit maximum size of stack allocations to 64kB

Fixes #791

src/jit/jit-irgen.c

@@ -36,7 +36,8 @@
 typedef struct _irgen_label irgen_label_t;
 typedef struct _patch_list  patch_list_t;
 
-#define PATCH_CHUNK_SZ 4
+#define PATCH_CHUNK_SZ  4
+#define MAX_STACK_ALLOC 65536
 
 struct _patch_list {
    patch_list_t *next;
@@ -3891,7 +3892,7 @@ static void irgen_locals(jit_irgen_t *g)
       for (int i = 0; i < nvars; i++) {
          vcode_type_t vtype = vcode_var_type(i);
          const int sz = irgen_size_bytes(vtype);
-         if (vcode_var_flags(i) & VAR_HEAP)
+         if ((vcode_var_flags(i) & VAR_HEAP) || sz > MAX_STACK_ALLOC)
             g->vars[i] = macro_lalloc(g, jit_value_from_int64(sz));
          else
             g->vars[i] = macro_salloc(g, sz);

test/regress/issue791.vhd

@@ -0,0 +1,25 @@
+entity issue791 is
+end entity;
+
+architecture beh of issue791 is
+
+  type t_slv_array is array (natural range <>) of bit_vector;
+
+  procedure read_mem is
+    -- This shouldn't be allocated on the stack
+    variable v_memory : t_slv_array(0 to (8 * 131072)-1)(7 downto 0) := (others => x"FF");
+  begin
+    wait for 1 ns;
+    v_memory(v_memory'right) := X"ab";
+    wait for 1 ns;
+    assert v_memory(v_memory'right) = X"ab";
+  end procedure;
+
+begin
+
+  p_proc : process
+  begin
+    read_mem;
+    wait;
+  end process;
+end architecture;

test/regress/testlist.txt

@@ -898,3 +898,4 @@ cover20         cover,shell
 issue787        normal
 view6           normal,2019
 issue790        normal
+issue791        normal,2008