[RFC,6/9] gas: dw2gencfi: ignore all .cfi_* directives with --scfi=all
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Commit Message
As we add support for --scfi=inline, this commit will need to evolve and
more changes may be necessary. More specifically, we will need to
explictly check the value of the enumerator flag_synth_cfi.
gas/
* dw2gencfi.c (dot_cfi): Ignore processing when synthesizing
CFI.
(dot_cfi_escape): Likewise.
(dot_cfi_personality): Likewise.
(dot_cfi_lsda): Likewise.
(dot_cfi_val_encoded_addr): Likewise.
(dot_cfi_label): Likewise.
(dot_cfi_sections): Likewise.
(dot_cfi_startproc): Likewise.
(dot_cfi_endproc): Likewise.
(dot_cfi_personality_id): Likewise.
(dot_cfi_fde_data): Likewise.
(dot_cfi_inline_lsda): Likewise.
---
gas/dw2gencfi.c | 72 +++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 72 insertions(+)
Comments
Hi Indu,
> @@ -806,6 +806,12 @@ dot_cfi (int arg)
> offsetT offset;
> unsigned reg1, reg2;
>
> + if (flag_synth_cfi)
> + {
> + ignore_rest_of_line ();
> + return;
> + }
> +
I am concerned about this behaviour. I understand that mixing
synthetic CFI statements and real ones would be a bad idea, but
I think that silently ignoring the real ones is a mistake. At
the very least you ought to generate a warning message letting
the user know that their cfi instructions are being ignored.
Cheers
Nick
On 9/28/23 07:10, Nick Clifton wrote:
> Hi Indu,
>
>> @@ -806,6 +806,12 @@ dot_cfi (int arg)
>> offsetT offset;
>> unsigned reg1, reg2;
>> + if (flag_synth_cfi)
>> + {
>> + ignore_rest_of_line ();
>> + return;
>> + }
>> +
>
> I am concerned about this behaviour. I understand that mixing
> synthetic CFI statements and real ones would be a bad idea, but
> I think that silently ignoring the real ones is a mistake. At
> the very least you ought to generate a warning message letting
> the user know that their cfi instructions are being ignored.
>
Yes, we could trigger one warning per function, when we see, say a
.cfi_startproc, for a asm function for which user specified --scfi=all:
"Warning: --scfi=all ignores sythesizable CFI directives for function
'foo'"
That said, it looks like for --scfi=all, we will need to honor at least
the following from the user:
- .cfi_sections
- .cfi_label
- .cfi_signal_frame
Thanks
@@ -806,6 +806,12 @@ dot_cfi (int arg)
offsetT offset;
unsigned reg1, reg2;
+ if (flag_synth_cfi)
+ {
+ ignore_rest_of_line ();
+ return;
+ }
+
if (frchain_now->frch_cfi_data == NULL)
{
as_bad (_("CFI instruction used without previous .cfi_startproc"));
@@ -936,6 +942,12 @@ dot_cfi_escape (int ignored ATTRIBUTE_UNUSED)
struct cfi_escape_data *head, **tail, *e;
struct cfi_insn_data *insn;
+ if (flag_synth_cfi)
+ {
+ ignore_rest_of_line ();
+ return;
+ }
+
if (frchain_now->frch_cfi_data == NULL)
{
as_bad (_("CFI instruction used without previous .cfi_startproc"));
@@ -974,6 +986,12 @@ dot_cfi_personality (int ignored ATTRIBUTE_UNUSED)
struct fde_entry *fde;
offsetT encoding;
+ if (flag_synth_cfi)
+ {
+ ignore_rest_of_line ();
+ return;
+ }
+
if (frchain_now->frch_cfi_data == NULL)
{
as_bad (_("CFI instruction used without previous .cfi_startproc"));
@@ -1045,6 +1063,12 @@ dot_cfi_lsda (int ignored ATTRIBUTE_UNUSED)
struct fde_entry *fde;
offsetT encoding;
+ if (flag_synth_cfi)
+ {
+ ignore_rest_of_line ();
+ return;
+ }
+
if (frchain_now->frch_cfi_data == NULL)
{
as_bad (_("CFI instruction used without previous .cfi_startproc"));
@@ -1118,6 +1142,12 @@ dot_cfi_val_encoded_addr (int ignored ATTRIBUTE_UNUSED)
struct cfi_insn_data *insn_ptr;
offsetT encoding;
+ if (flag_synth_cfi)
+ {
+ ignore_rest_of_line ();
+ return;
+ }
+
if (frchain_now->frch_cfi_data == NULL)
{
as_bad (_("CFI instruction used without previous .cfi_startproc"));
@@ -1183,6 +1213,12 @@ dot_cfi_label (int ignored ATTRIBUTE_UNUSED)
{
char *name;
+ if (flag_synth_cfi)
+ {
+ ignore_rest_of_line ();
+ return;
+ }
+
if (frchain_now->frch_cfi_data == NULL)
{
as_bad (_("CFI instruction used without previous .cfi_startproc"));
@@ -1211,6 +1247,12 @@ dot_cfi_sections (int ignored ATTRIBUTE_UNUSED)
{
int sections = 0;
+ if (flag_synth_cfi)
+ {
+ ignore_rest_of_line ();
+ return;
+ }
+
SKIP_WHITESPACE ();
if (is_name_beginner (*input_line_pointer) || *input_line_pointer == '"')
while (1)
@@ -1278,6 +1320,12 @@ dot_cfi_startproc (int ignored ATTRIBUTE_UNUSED)
{
int simple = 0;
+ if (flag_synth_cfi)
+ {
+ ignore_rest_of_line ();
+ return;
+ }
+
if (frchain_now->frch_cfi_data != NULL)
{
as_bad (_("previous CFI entry not closed (missing .cfi_endproc)"));
@@ -1318,6 +1366,12 @@ dot_cfi_startproc (int ignored ATTRIBUTE_UNUSED)
static void
dot_cfi_endproc (int ignored ATTRIBUTE_UNUSED)
{
+ if (flag_synth_cfi)
+ {
+ ignore_rest_of_line ();
+ return;
+ }
+
if (frchain_now->frch_cfi_data == NULL)
{
as_bad (_(".cfi_endproc without corresponding .cfi_startproc"));
@@ -1382,6 +1436,12 @@ dot_cfi_personality_id (int ignored ATTRIBUTE_UNUSED)
{
struct fde_entry *fde;
+ if (flag_synth_cfi)
+ {
+ ignore_rest_of_line ();
+ return;
+ }
+
if (frchain_now->frch_cfi_data == NULL)
{
as_bad (_("CFI instruction used without previous .cfi_startproc"));
@@ -1403,6 +1463,12 @@ dot_cfi_personality_id (int ignored ATTRIBUTE_UNUSED)
static void
dot_cfi_fde_data (int ignored ATTRIBUTE_UNUSED)
{
+ if (flag_synth_cfi)
+ {
+ ignore_rest_of_line ();
+ return;
+ }
+
if (frchain_now->frch_cfi_data == NULL)
{
as_bad (_(".cfi_fde_data without corresponding .cfi_startproc"));
@@ -1511,6 +1577,12 @@ dot_cfi_inline_lsda (int ignored ATTRIBUTE_UNUSED)
int align;
long max_alignment = 28;
+ if (flag_synth_cfi)
+ {
+ ignore_rest_of_line ();
+ return;
+ }
+
if (!last_fde)
{
as_bad (_("unexpected .cfi_inline_lsda"));