From b405b91a11df9c75e44bc49edc76a4249d258f53 Mon Sep 17 00:00:00 2001
From: Nick Gasson <nick@nickg.me.uk>
Date: Thu, 7 Dec 2017 17:54:36 +0000
Subject: [PATCH] Constant folding for param upref instruction. Fixes #345

---
 src/eval.c             | 16 +++++++++++++
 test/simp/issue345.vhd | 51 ++++++++++++++++++++++++++++++++++++++++++
 test/test_simp.c       | 11 +++++++++
 3 files changed, 78 insertions(+)
 create mode 100644 test/simp/issue345.vhd

diff --git a/src/eval.c b/src/eval.c
index d0571be5..2e0831fe 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -961,6 +961,18 @@ static void eval_op_fcall(int op, eval_state_t *state)
    eval_free_context(context);
 }
 
+static void eval_op_param_upref(int op, eval_state_t *state)
+{
+   context_t *where = state->context;
+   const int hops = vcode_get_hops(op);
+   for (int i = 0; i < hops; i++)
+      where = where->parent;
+
+   value_t *src = &(where->regs[vcode_get_arg(op, 0)]);
+   value_t *dst = eval_get_reg(vcode_get_result(op), state);
+   *dst = *src;
+}
+
 static void eval_op_bounds(int op, eval_state_t *state)
 {
    value_t *reg = eval_get_reg(vcode_get_arg(op, 0), state);
@@ -2053,6 +2065,10 @@ static void eval_vcode(eval_state_t *state)
          eval_op_addi(i, state);
          break;
 
+      case VCODE_OP_PARAM_UPREF:
+         eval_op_param_upref(i, state);
+         break;
+
       default:
          vcode_dump();
          fatal("cannot evaluate vcode op %s", vcode_op_string(vcode_get_op(i)));
diff --git a/test/simp/issue345.vhd b/test/simp/issue345.vhd
new file mode 100644
index 00000000..0b297dc0
--- /dev/null
+++ b/test/simp/issue345.vhd
@@ -0,0 +1,51 @@
+package pkg is
+  function func (s : string) return natural;
+  function func2 (s : natural) return natural;
+  function func3(x : integer) return integer;
+end package;
+
+package body pkg is
+  function func(s : string) return natural is
+    function inner_func return natural is
+    begin
+      return s'length;
+    end;
+  begin
+    return inner_func;
+  end;
+
+  function func2(s : natural) return natural is
+    function inner_func return natural is
+    begin
+      return s;
+    end;
+  begin
+    return inner_func;
+  end;
+
+  function func3(x : integer) return integer is
+      function inner(n : integer) return integer is
+      begin
+          return x + n;
+      end function;
+  begin
+      return inner(2);
+  end function;
+end;
+
+use work.pkg.all;
+
+entity bug is
+end entity;
+
+architecture a of bug is
+begin
+  main : process
+  begin
+    assert func("") = 0;
+    assert func("abc") = 3;
+    assert func2(10) = 10;
+    assert func3(5) = 7;
+    wait;
+  end process;
+end;
diff --git a/test/test_simp.c b/test/test_simp.c
index 3ac235f4..1b9651ba 100644
--- a/test/test_simp.c
+++ b/test/test_simp.c
@@ -566,6 +566,16 @@ START_TEST(test_issue344)
 }
 END_TEST
 
+START_TEST(test_issue345)
+{
+   input_from_file(TESTDIR "/simp/issue345.vhd");
+
+   tree_t top = run_elab();
+
+   fail_unless(tree_stmts(top) == 0);
+}
+END_TEST
+
 int main(void)
 {
    Suite *s = suite_create("simplify");
@@ -589,6 +599,7 @@ int main(void)
    tcase_add_test(tc_core, test_issue331);
    tcase_add_test(tc_core, test_issue332);
    tcase_add_test(tc_core, test_issue344);
+   tcase_add_test(tc_core, test_issue345);
    suite_add_tcase(s, tc_core);
 
    return nvc_run_test(s);
-- 
2.39.2