From 16d345b1b0463574ff7baad7df662254f168031a Mon Sep 17 00:00:00 2001
From: Nick Gasson <nick@nickg.me.uk>
Date: Tue, 18 Oct 2022 22:29:16 +0100
Subject: [PATCH] Incorrect copying of record initial value. Fixes #549

---
 src/lower.c               | 40 ++++++++++++++++++++++++++++-------
 test/regress/issue549.vhd | 44 +++++++++++++++++++++++++++++++++++++++
 test/regress/testlist.txt |  1 +
 test/test_lower.c         |  3 ---
 4 files changed, 78 insertions(+), 10 deletions(-)
 create mode 100644 test/regress/issue549.vhd

diff --git a/src/lower.c b/src/lower.c
index 88839e0d..6e075467 100644
--- a/src/lower.c
+++ b/src/lower.c
@@ -4393,8 +4393,11 @@ static vcode_reg_t lower_default_value(type_t type, vcode_reg_t hint_reg,
       const int nfields = type_fields(type);
       vcode_type_t vtype = lower_type(type);
 
-      vcode_var_t tmp_var = lower_temp_var("def", vtype, vtype);
-      vcode_reg_t mem_reg = emit_index(tmp_var, VCODE_INVALID_REG);
+      vcode_reg_t mem_reg = hint_reg;
+      if (hint_reg == VCODE_INVALID_REG) {
+         vcode_var_t tmp_var = lower_temp_var("def", vtype, vtype);
+         mem_reg = emit_index(tmp_var, VCODE_INVALID_REG);
+      }
 
       tree_t rcon = shift_constraints(&cons, &ncons, 1);
       assert(ncons == 0);   // Cannot have more constraints following record
@@ -4843,15 +4846,33 @@ static void lower_copy_record_cb(type_t ftype, vcode_reg_t dst_ptr,
       if (lower_have_uarray_ptr(src_reg))
          src_reg = emit_load_indirect(src_ptr);
 
+      vcode_reg_t count_reg = lower_array_total_len(ftype, src_reg);
+
       vcode_reg_t dst_reg = dst_ptr;
-      if (lower_have_uarray_ptr(dst_reg))
-         dst_reg = emit_load_indirect(dst_ptr);
+      if (where == NULL) {
+         // Initialising a variable, need to allocate an array of the
+         // correct length
+         if (lower_have_uarray_ptr(dst_reg)) {
+            type_t scalar_elem = lower_elem_recur(ftype);
+            vcode_type_t vtype = lower_type(scalar_elem);
+            vcode_type_t vbounds = lower_bounds(scalar_elem);
+            vcode_reg_t mem_reg = emit_alloc(vtype, vbounds, count_reg);
+            vcode_reg_t wrap_reg = lower_rewrap(mem_reg, src_reg);
 
-      lower_check_array_sizes(where, ftype, ftype, dst_reg, src_reg);
+            emit_store_indirect(wrap_reg, dst_ptr);
+            dst_reg = wrap_reg;
+         }
+      }
+      else {
+         // Overwriting an existing array, check the length
+         if (lower_have_uarray_ptr(dst_reg))
+            dst_reg = emit_load_indirect(dst_ptr);
+
+         lower_check_array_sizes(where, ftype, ftype, dst_reg, src_reg);
+      }
 
       vcode_reg_t src_data = lower_array_data(src_reg);
       vcode_reg_t dst_data = lower_array_data(dst_reg);
-      vcode_reg_t count_reg = lower_array_total_len(ftype, dst_reg);
       emit_copy(dst_data, src_data, count_reg);
    }
    else if (type_is_record(ftype)) {
@@ -6414,7 +6435,12 @@ static void lower_var_decl(tree_t decl)
       }
    }
    else if (type_is_record(type)) {
-      emit_copy(dest_reg, value_reg, VCODE_INVALID_REG);
+      if (value_reg != dest_reg && !lower_const_bounds(type)) {
+         // We need to allocate memory for some of the fields
+         lower_copy_record(type, dest_reg, value_reg, NULL);
+      }
+      else
+         emit_copy(dest_reg, value_reg, VCODE_INVALID_REG);
    }
    else if (type_is_scalar(type)) {
       lower_check_scalar_bounds(value_reg, type, decl, decl);
diff --git a/test/regress/issue549.vhd b/test/regress/issue549.vhd
new file mode 100644
index 00000000..14283a44
--- /dev/null
+++ b/test/regress/issue549.vhd
@@ -0,0 +1,44 @@
+package pack is
+    constant C : integer;
+
+    type rec is record
+        x : integer;
+        y : bit_vector(1 to C);
+    end record;
+
+end package;
+
+package body pack is
+    constant C : integer := 4;
+end package body;
+
+-------------------------------------------------------------------------------
+
+entity issue549 is
+end entity;
+
+use work.pack.all;
+
+architecture test of issue549 is
+
+    constant def : rec := (x => 0, y => "0000");
+
+    procedure modify (variable arg : inout rec) is
+    begin
+        arg.y(1) := '1';
+    end procedure;
+
+    procedure test (arg : in rec) is
+        variable copy : rec := def;
+    begin
+        copy.y := arg.y;
+        modify(copy);
+        assert def.y = "0000";
+        assert copy.y = "1110";
+    end procedure;
+
+begin
+
+    p1: test((x => 1, y => "0110"));
+
+end architecture;
diff --git a/test/regress/testlist.txt b/test/regress/testlist.txt
index f39a62a4..2b8ea4a5 100644
--- a/test/regress/testlist.txt
+++ b/test/regress/testlist.txt
@@ -683,3 +683,4 @@ ename4          normal,2008
 genpack12       normal,2008
 wave8           shell
 signal28        normal,relaxed
+issue549        normal
diff --git a/test/test_lower.c b/test/test_lower.c
index 050b8eb0..50b77ef9 100644
--- a/test/test_lower.c
+++ b/test/test_lower.c
@@ -4607,7 +4607,6 @@ START_TEST(test_vunit5)
 
    EXPECT_BB(0) = {
       { VCODE_OP_INDEX, .name = "R" },
-      { VCODE_OP_INDEX, .name = "*def" },
       { VCODE_OP_RECORD_REF, .field = 0 },
       { VCODE_OP_UARRAY_LEN },
       { VCODE_OP_CAST },
@@ -4624,8 +4623,6 @@ START_TEST(test_vunit5)
       { VCODE_OP_MEMSET },
       { VCODE_OP_WRAP },
       { VCODE_OP_STORE_INDIRECT },
-      { VCODE_OP_COPY },
-      { VCODE_OP_RECORD_REF, .field = 0 },
       { VCODE_OP_LOAD_INDIRECT },
       { VCODE_OP_UARRAY_LEN },
       { VCODE_OP_UNWRAP },
-- 
2.39.2