From 55708e99aca33f2ee9036732d778cd5899d2a2b0 Mon Sep 17 00:00:00 2001 From: Tom Tromey Date: Tue, 5 Nov 2019 10:12:27 -0700 Subject: Allow re-assigning to convenience variables A customer reported somewhat odd gdb behavior, where re-assigning an array or string to a convenience variable would yield "Too many array elements". A test case is: (gdb) p $x = "x" (gdb) p $x = "xyz" This patch fixes the problem by making a special case in the evaluator for assignment to convenience variables, which seems like the correct behavior. Note that a previous patch implemented this for Ada, see commit f411722cb ("Allow re-assigning to convenience variables"). gdb/ChangeLog 2019-11-14 Tom Tromey * eval.c (evaluate_subexp_standard) : Do not pass an expected type for the RHS if the LHS is a convenience variable. gdb/testsuite/ChangeLog 2019-11-14 Tom Tromey * gdb.base/gdbvars.exp (test_convenience_variables): Add regression tests. Change-Id: I5e66a2d243931a5c43c7af4bc9f6717464c2477e --- gdb/ChangeLog | 5 +++++ gdb/eval.c | 9 ++++++++- gdb/testsuite/ChangeLog | 5 +++++ gdb/testsuite/gdb.base/gdbvars.exp | 15 +++++++++++++++ 4 files changed, 33 insertions(+), 1 deletion(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 719574f3096..1a84242839b 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,8 @@ +2019-11-14 Tom Tromey + + * eval.c (evaluate_subexp_standard) : Do not pass an + expected type for the RHS if the LHS is a convenience variable. + 2019-11-14 Simon Marchi * unittests/vec-utils-selftests.c (unordered_remove_tests::obj): diff --git a/gdb/eval.c b/gdb/eval.c index 139fd68aaa9..71e79d623a3 100644 --- a/gdb/eval.c +++ b/gdb/eval.c @@ -2151,7 +2151,14 @@ evaluate_subexp_standard (struct type *expect_type, case BINOP_ASSIGN: arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside); - arg2 = evaluate_subexp (value_type (arg1), exp, pos, noside); + /* Special-case assignments where the left-hand-side is a + convenience variable -- in these, don't bother setting an + expected type. This avoids a weird case where re-assigning a + string or array to an internal variable could error with "Too + many array elements". */ + arg2 = evaluate_subexp (VALUE_LVAL (arg1) == lval_internalvar + ? NULL_TYPE : value_type (arg1), + exp, pos, noside); if (noside == EVAL_SKIP || noside == EVAL_AVOID_SIDE_EFFECTS) return arg1; diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index 7416b820d78..3a4d2294706 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2019-11-14 Tom Tromey + + * gdb.base/gdbvars.exp (test_convenience_variables): Add + regression tests. + 2019-11-12 Tom Tromey * lib/tuiterm.exp (_accept): Add wait_for parameter. Check output diff --git a/gdb/testsuite/gdb.base/gdbvars.exp b/gdb/testsuite/gdb.base/gdbvars.exp index 8259115b7fb..a4e5b417ac5 100644 --- a/gdb/testsuite/gdb.base/gdbvars.exp +++ b/gdb/testsuite/gdb.base/gdbvars.exp @@ -51,6 +51,21 @@ proc test_convenience_variables {} { gdb_test "print \$bar" " = void" \ "Print contents of uninitialized convenience variable" + + + gdb_test "print \$str = \"some string\"" \ + " = \"some string\"" \ + "Set convenience variable to string value" + gdb_test "print \$str = \"some other string\"" \ + " = \"some other string\"" \ + "Change convenience variable to different string value" + + gdb_test "print \$arr = {1, 2, 3}" \ + " = \\{1, 2, 3\\}" \ + "Set convenience variable to array value" + gdb_test "print \$arr = {0, 1, 2, 3}" \ + " = \\{0, 1, 2, 3\\}" \ + "Set convenience variable to different array value" } proc test_convenience_functions {} { -- cgit v1.2.3-65-gdbad