Patchwork [1/2] Fix big-endian aggregate assignment in Ada

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Submitter Tom Tromey
Date April 29, 2019, 6:47 p.m.
Message ID <20190429184744.2239-2-tromey@adacore.com>
Download mbox | patch
Permalink /patch/32464/
State New
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Comments

Tom Tromey - April 29, 2019, 6:47 p.m.
A bug internal to AdaCore notes that assigning a non-scalar value to
an element of a packed array will sometimes fail.

The bug turns out to be that ada_value_assign incorrectly computes the
starting point for the assignment.  This patch fixes the problem.

gdb/ChangeLog
2019-04-29  Tom Tromey  <tromey@adacore.com>

	* ada-lang.c (ada_value_assign): Correctly compute starting offset
	for big-endian copies.

gdb/testsuite/ChangeLog
2019-04-29  Tom Tromey  <tromey@adacore.com>

	* gdb.ada/packed_array_assign.exp: Add packed assignment
	regression test.
---
 gdb/ChangeLog                                 |  5 +++++
 gdb/ada-lang.c                                | 14 ++++++++------
 gdb/testsuite/ChangeLog                       |  5 +++++
 gdb/testsuite/gdb.ada/packed_array_assign.exp |  5 +++++
 4 files changed, 23 insertions(+), 6 deletions(-)

Patch

diff --git a/gdb/ada-lang.c b/gdb/ada-lang.c
index 250ce438b1a..422bfdb3b8d 100644
--- a/gdb/ada-lang.c
+++ b/gdb/ada-lang.c
@@ -2709,12 +2709,14 @@  ada_value_assign (struct value *toval, struct value *fromval)
       from_size = value_bitsize (fromval);
       if (from_size == 0)
 	from_size = TYPE_LENGTH (value_type (fromval)) * TARGET_CHAR_BIT;
-      if (gdbarch_bits_big_endian (get_type_arch (type)))
-        copy_bitwise (buffer, value_bitpos (toval),
-		      value_contents (fromval), from_size - bits, bits, 1);
-      else
-        copy_bitwise (buffer, value_bitpos (toval),
-		      value_contents (fromval), 0, bits, 0);
+
+      const int is_big_endian = gdbarch_bits_big_endian (get_type_arch (type));
+      ULONGEST from_offset = 0;
+      if (is_big_endian && is_scalar_type (value_type (fromval)))
+	from_offset = from_size - bits;
+      copy_bitwise (buffer, value_bitpos (toval),
+		    value_contents (fromval), from_offset,
+		    bits, is_big_endian);
       write_memory_with_notification (to_addr, buffer, len);
 
       val = value_copy (toval);
diff --git a/gdb/testsuite/gdb.ada/packed_array_assign.exp b/gdb/testsuite/gdb.ada/packed_array_assign.exp
index 93910ac6cb4..8ed2d63ecf3 100644
--- a/gdb/testsuite/gdb.ada/packed_array_assign.exp
+++ b/gdb/testsuite/gdb.ada/packed_array_assign.exp
@@ -28,3 +28,8 @@  runto "aggregates.run_test"
 gdb_test \
     "print pra := ((packed_array_assign_x => 2, packed_array_assign_y => 0, packed_array_assign_w => 17), pr, (packed_array_assign_x => 7, packed_array_assign_y => 1, packed_array_assign_w => 23))" \
     " = \\(\\(packed_array_assign_w => 17, packed_array_assign_x => 2, packed_array_assign_y => 0\\), \\(packed_array_assign_w => 104, packed_array_assign_x => 2, packed_array_assign_y => 3\\), \\(packed_array_assign_w => 23, packed_array_assign_x => 7, packed_array_assign_y => 1\\)\\)"
+
+gdb_test "print pra(1) := pr" \
+    " = \\(packed_array_assign_w => 104, packed_array_assign_x => 2, packed_array_assign_y => 3\\)"
+gdb_test "print pra(1)" \
+    " = \\(packed_array_assign_w => 104, packed_array_assign_x => 2, packed_array_assign_y => 3\\)"