From cd8c307d930da2983292197f190c615b560efe4a Mon Sep 17 00:00:00 2001
From: Nick Gasson <nick@nickg.me.uk>
Date: Fri, 8 Mar 2024 14:29:59 +0000
Subject: [PATCH] Fix crash after error in external name. Fixes #860

---
 src/lower.c            |  9 ++++++--
 test/elab/issue860.vhd | 49 ++++++++++++++++++++++++++++++++++++++++++
 test/test_elab.c       | 21 ++++++++++++++++++
 3 files changed, 77 insertions(+), 2 deletions(-)
 create mode 100644 test/elab/issue860.vhd

diff --git a/src/lower.c b/src/lower.c
index a6d6c28c..6bcc2b65 100644
--- a/src/lower.c
+++ b/src/lower.c
@@ -3027,8 +3027,13 @@ static vcode_reg_t lower_external_name(lower_unit_t *lu, tree_t ref)
    if (decl == NULL) {
       type_t type = tree_type(ref);
       vcode_type_t vbounds = lower_bounds(type);
-      if (tree_class(ref) == C_SIGNAL)
-         return emit_undefined(lower_signal_type(type), vbounds);
+      if (tree_class(ref) == C_SIGNAL) {
+         vcode_type_t vstype = lower_signal_type(type);
+         if (type_is_homogeneous(type))
+            return emit_undefined(vstype, vbounds);
+         else
+            return emit_undefined(vtype_pointer(vstype), vbounds);
+      }
       else
          return emit_undefined(vtype_pointer(lower_type(type)), vbounds);
    }
diff --git a/test/elab/issue860.vhd b/test/elab/issue860.vhd
new file mode 100644
index 00000000..9e3a3ad4
--- /dev/null
+++ b/test/elab/issue860.vhd
@@ -0,0 +1,49 @@
+package pack is
+    type t_sbi_if is record
+        addr  : bit_vector;
+        wdata : bit_vector;
+        rdata : bit_vector;
+    end record;
+end package;
+
+use work.pack.all;
+
+entity ethernet_th is
+  generic(
+    GC_SBI_ADDR_WIDTH : positive := 8;
+    GC_SBI_DATA_WIDTH : positive := 8
+  );
+end entity ethernet_th;
+
+architecture struct_sbi of ethernet_th is
+  signal clk       : bit;
+  signal i1_sbi_if : t_sbi_if(addr(GC_SBI_ADDR_WIDTH - 1 downto 0), wdata(GC_SBI_DATA_WIDTH - 1 downto 0), rdata(GC_SBI_DATA_WIDTH - 1 downto 0));
+begin
+end architecture struct_sbi;
+
+use work.pack.all;
+
+entity test is
+  generic(
+    GC_DATA_WIDTH : positive := 8);
+end entity;
+
+architecture tb of test is
+  constant C_ADDR_WIDTH : positive := 8;
+
+  alias clk is << signal .test.i_test_harness.clk : bit >>;  -- Error
+  alias i1_sbi_if is << signal .test.i_test_harness.i1_sbi_if :
+      t_sbi_if(addr(C_ADDR_WIDTH - 1 downto 0), wdata(GC_DATA_WIDTH - 1 downto 0), rdata(GC_DATA_WIDTH - 1 downto 0)) >>; -- Error
+begin
+
+  i_test_harness : entity work.ethernet_th(struct_sbi)
+    generic map(
+      GC_SBI_ADDR_WIDTH => C_ADDR_WIDTH,
+      GC_SBI_DATA_WIDTH => GC_DATA_WIDTH
+    );
+
+  p_main: process
+  begin
+    wait;
+  end process p_main;
+end architecture;
diff --git a/test/test_elab.c b/test/test_elab.c
index 5b9fedd0..ccd6a2d4 100644
--- a/test/test_elab.c
+++ b/test/test_elab.c
@@ -1878,6 +1878,26 @@ START_TEST(test_issue864)
 }
 END_TEST
 
+START_TEST(test_issue860)
+{
+   set_standard(STD_08);
+
+   input_from_file(TESTDIR "/elab/issue860.vhd");
+
+   const error_t expect[] = {
+      { 34, "external name CLK not found" },
+      { 35, "external name I1_SBI_IF not found" },
+      { -1, NULL }
+   };
+   expect_errors(expect);
+
+   tree_t e = run_elab();
+   fail_unless(e == NULL);
+
+   check_expected_errors();
+}
+END_TEST
+
 Suite *get_elab_tests(void)
 {
    Suite *s = suite_create("elab");
@@ -1978,6 +1998,7 @@ Suite *get_elab_tests(void)
    tcase_add_test(tc, test_ename3);
    tcase_add_test(tc, test_issue855);
    tcase_add_test(tc, test_issue864);
+   tcase_add_test(tc, test_issue860);
    suite_add_tcase(s, tc);
 
    return s;
-- 
2.39.2