From 628c73d984fd7663607cc3fd9368f809855906fd Mon Sep 17 00:00:00 2001 From: Robin Haberkorn Date: Sun, 13 Apr 2025 00:40:37 +0300 Subject: fixed undoing bitfields on Windows * It turns out that `bool` (_Bool) in bitfields may cause padding to the next 32-bit word. This was only observed on MinGW. I am not entirely sure why, although the C standard does not guarantee much with regard to bitfield memory layout and there are 64-bit available due to passing anyway. Actually, they could also be layed out in a different order. * I am now consistently using guint instead of `bool` in bitfields to prevent any potential surprises. * The way that guint was aliased with bitfield structs for undoing teco_machine_main_t and teco_machine_qregspec_t flags was therefore insecure. It was not guaranteed that the __flags field really "captures" all of the bit field. Even with `guint v : 1` fields, this was not guaranteed. We would have required a static assertion for robustness. Alternatively, we could have declared a `gsize __flags` variable as well. This __should__ be safe since gsize should always be pointer sized and correspond to the platform's alignment. However, it's also not 100% guaranteed. Using classic ANSI C enums with bit operations to encode multiple fields and flags into a single integer also doesn't look very attractive. * Instead, we now define scalar types with their own teco_undo_push() shortcuts for the bitfield structs. This is in one way simpler and much more robust, but on the other hand complicates access to the flag variables. * It's a good question whether a `struct __attribute__((packed))` bitfield with guint fields would be a reliable replacement for flag enums, that are communicated with the "outside" (TECO) world. I am not going to risk it until GCC gives any guarantees, though. For the time being, bitfields are only used internally where the concrete memory layout (bit positions) is not crucial. * This fixes the test suite and therefore probably CI and nightly builds on Windows. * Test case: Rub out `@I//` or `@Xq` until before the `@`. The parser doesn't know that `@` is still set and allows all sorts of commands where `@` should be forbidden. * It's unknown how long this has been broken on Windows - quite possibly since v2.0. --- src/goto-commands.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'src/goto-commands.c') diff --git a/src/goto-commands.c b/src/goto-commands.c index e335c70..a0e6634 100644 --- a/src/goto-commands.c +++ b/src/goto-commands.c @@ -76,8 +76,8 @@ teco_state_label_input(teco_machine_main_t *ctx, gunichar chr, GError **error) memset(&teco_goto_skip_label, 0, sizeof(teco_goto_skip_label)); if (ctx->parent.must_undo) - teco_undo_guint(ctx->__flags); - ctx->mode = TECO_MODE_NORMAL; + teco_undo_flags(ctx->flags); + ctx->flags.mode = TECO_MODE_NORMAL; } } else if (existing_pc != ctx->macro_pc) { g_autofree gchar *label_printable = teco_string_echo(ctx->goto_label.data, @@ -115,7 +115,7 @@ TECO_DEFINE_STATE(teco_state_label, static teco_state_t * teco_state_goto_done(teco_machine_main_t *ctx, const teco_string_t *str, GError **error) { - if (ctx->mode > TECO_MODE_NORMAL) + if (ctx->flags.mode > TECO_MODE_NORMAL) return &teco_state_start; teco_int_t value; @@ -148,8 +148,8 @@ teco_state_goto_done(teco_machine_main_t *ctx, const teco_string_t *str, GError undo__teco_string_truncate(&teco_goto_skip_label, 0); teco_string_init(&teco_goto_skip_label, label.data, label.len); if (ctx->parent.must_undo) - teco_undo_guint(ctx->__flags); - ctx->mode = TECO_MODE_PARSE_ONLY_GOTO; + teco_undo_flags(ctx->flags); + ctx->flags.mode = TECO_MODE_PARSE_ONLY_GOTO; } } -- cgit v1.2.3