* prevent "undef var" errors on gcc --help or --version
@ 2016-01-08 13:23 Olivier Hainque
2016-01-11 16:09 ` Bernd Schmidt
0 siblings, 1 reply; 5+ messages in thread
From: Olivier Hainque @ 2016-01-08 13:23 UTC (permalink / raw)
To: GCC Patches
[-- Attachment #1: Type: text/plain, Size: 1316 bytes --]
Hello,
self-specs setup with configure --with-specs are allowed to contain %:getenv
environment variable references. We are using this capability in a few cases
for cross ports.
In such configurations, gcc --help or gcc --version fail if the variables
aren't defined, like so:
gcc --version
Using built-in specs.
gcc: fatal error: environment variable ‘<VARIABLE_NAME_HERE>’ not defined
compilation terminated.
It is a bit annoying to have to define environment variables just to
be able to retrieve version info. We have been using a close variant of
the attached patch to address this on gcc-4.7 and 4.9 for a while now.
The patch was adjusted for mainline, I tested that it still operates
as intended and performed a regular bootstrap + testsuite cycle showing
no regression on x86_64-linux.
OK to commit ?
Thanks much in advance for your feedback,
With Kind Regards,
Olivier
2016-01-08 Olivier Hainque <hainque@adacore.com>
* gcc.c (spec_undefvar_allowed): New global.
(process_command): Set to true when running for --version or --help
alone, or together.
(getenv_spec_function): When the variable is not defined, use the
variable name as the variable value if we're allowed not to issue
a fatal error.
[-- Attachment #2: spec-undefvar.diff --]
[-- Type: application/octet-stream, Size: 2300 bytes --]
--- a/gcc/gcc.c
+++ b/gcc/gcc.c
@@ -3299,6 +3299,11 @@ int n_infiles;
static int n_infiles_alloc;
+/* True if undefined environment variables encountered during spec processing
+ are ok to ignore, typically when we're running for --help or --version. */
+
+static bool spec_undefvar_allowed;
+
/* True if multiple input files are being compiled to a single
assembly file. */
@@ -4542,6 +4547,15 @@ process_command (unsigned int decoded_options_count,
add_infile ("help-dummy", "c");
}
+ /* Undefined variable references in specs are harmless if
+ we're running for --help or --version alone, or together. */
+ spec_undefvar_allowed =
+ (((print_version || print_help_list)
+ && decoded_options_count == 2)
+ ||
+ ((print_version && print_help_list)
+ && decoded_options_count == 3));
+
alloc_switch ();
switches[n_switches].part1 = 0;
alloc_infile ();
@@ -9085,14 +9099,17 @@ print_multilib_info (void)
\f
/* getenv built-in spec function.
- Returns the value of the environment variable given by its first
- argument, concatenated with the second argument. If the
- environment variable is not defined, a fatal error is issued. */
+ Returns the value of the environment variable given by its first argument,
+ concatenated with the second argument. If the variable is not defined, a
+ fatal error is issued unless such undefs are internally allowed, in which
+ case the variable name is used as the variable value. */
static const char *
getenv_spec_function (int argc, const char **argv)
{
const char *value;
+ const char *varname;
+
char *result;
char *ptr;
size_t len;
@@ -9100,10 +9117,15 @@ getenv_spec_function (int argc, const char **argv)
if (argc != 2)
return NULL;
- value = env.get (argv[0]);
+ varname = argv[0];
+ value = env.get (varname);
+
+ if (!value && spec_undefvar_allowed)
+ value = varname;
+
if (!value)
fatal_error (input_location,
- "environment variable %qs not defined", argv[0]);
+ "environment variable %qs not defined", varname);
/* We have to escape every character of the environment variable so
they are not interpreted as active spec characters. A
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: prevent "undef var" errors on gcc --help or --version
2016-01-08 13:23 prevent "undef var" errors on gcc --help or --version Olivier Hainque
@ 2016-01-11 16:09 ` Bernd Schmidt
2016-01-12 16:11 ` Olivier Hainque
0 siblings, 1 reply; 5+ messages in thread
From: Bernd Schmidt @ 2016-01-11 16:09 UTC (permalink / raw)
To: Olivier Hainque, GCC Patches
On 01/08/2016 02:23 PM, Olivier Hainque wrote:
> + /* Undefined variable references in specs are harmless if
> + we're running for --help or --version alone, or together. */
> + spec_undefvar_allowed =
> + (((print_version || print_help_list)
> + && decoded_options_count == 2)
> + ||
> + ((print_version && print_help_list)
> + && decoded_options_count == 3));
> +
This doesn't follow the formatting rules. Also, there are a couple of
other options that cause gcc to just print something and exit. Are these
affected by missing env vars?
Bernd
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: prevent "undef var" errors on gcc --help or --version
2016-01-11 16:09 ` Bernd Schmidt
@ 2016-01-12 16:11 ` Olivier Hainque
2016-01-12 16:14 ` Bernd Schmidt
0 siblings, 1 reply; 5+ messages in thread
From: Olivier Hainque @ 2016-01-12 16:11 UTC (permalink / raw)
To: Bernd Schmidt; +Cc: GCC Patches
[-- Attachment #1: Type: text/plain, Size: 1446 bytes --]
Hello Bernd,
Thanks for your feedback on this :-)
> On 11 Jan 2016, at 17:09, Bernd Schmidt <bschmidt@redhat.com> wrote:
>
> On 01/08/2016 02:23 PM, Olivier Hainque wrote:
>> + /* Undefined variable references in specs are harmless if
>> + we're running for --help or --version alone, or together. */
>> + spec_undefvar_allowed =
>> + (((print_version || print_help_list)
>> + && decoded_options_count == 2)
>> + ||
>> + ((print_version && print_help_list)
>> + && decoded_options_count == 3));
>> +
>
> This doesn't follow the formatting rules.
Arg, indeed. Revised version attached.
> Also, there are a couple of other options that cause gcc to just print something and exit. Are these affected by missing env vars?
Some of these, for sure. For example, a common use case here is to
define a default --sysroot. We need this to be set properly for at
least --print-search-dirs and --print-prog-name, probably --print-file-name.
The print-multi family might be ok. It's heavily based on the presence
of other options on the command line, but maybe never depending on argument
values. I wasn't ready to bet though and opted for a conservative approach
first.
The attached patch is doing the same as the previous one, except more
explicitly and making it easier to adapt if deemed useful.
I could extract the decision code in a separate function if you prefer.
Olivier
[-- Attachment #2: spec-undef.diff --]
[-- Type: application/octet-stream, Size: 2763 bytes --]
diff --git a/gcc/gcc.c b/gcc/gcc.c
index 319a073..92fb051 100644
--- a/gcc/gcc.c
+++ b/gcc/gcc.c
@@ -3299,6 +3299,11 @@ int n_infiles;
static int n_infiles_alloc;
+/* True if undefined environment variables encountered during spec processing
+ are ok to ignore, typically when we're running for --help or --version. */
+
+static bool spec_undefvar_allowed;
+
/* True if multiple input files are being compiled to a single
assembly file. */
@@ -4542,6 +4547,27 @@ process_command (unsigned int decoded_options_count,
add_infile ("help-dummy", "c");
}
+ /* Decide if undefined variable references are allowed in specs. */
+ {
+ /* --version and --help alone or together are safe. Note that -v would
+ make them unsafe, as they'd then be run for subprocesses as well, the
+ location of which might depend on variables possibly coming from
+ self-specs. */
+
+ /* Count the number of options we have for which undefined variables
+ are harmless for sure, and check that nothing else is set. */
+
+ unsigned n_varsafe_options = 0;
+
+ if (print_version)
+ n_varsafe_options++;
+
+ if (print_help_list)
+ n_varsafe_options++;
+
+ spec_undefvar_allowed = (decoded_options_count == n_varsafe_options + 1);
+ }
+
alloc_switch ();
switches[n_switches].part1 = 0;
alloc_infile ();
@@ -9085,14 +9111,17 @@ print_multilib_info (void)
\f
/* getenv built-in spec function.
- Returns the value of the environment variable given by its first
- argument, concatenated with the second argument. If the
- environment variable is not defined, a fatal error is issued. */
+ Returns the value of the environment variable given by its first argument,
+ concatenated with the second argument. If the variable is not defined, a
+ fatal error is issued unless such undefs are internally allowed, in which
+ case the variable name is used as the variable value. */
static const char *
getenv_spec_function (int argc, const char **argv)
{
const char *value;
+ const char *varname;
+
char *result;
char *ptr;
size_t len;
@@ -9100,10 +9129,15 @@ getenv_spec_function (int argc, const char **argv)
if (argc != 2)
return NULL;
- value = env.get (argv[0]);
+ varname = argv[0];
+ value = env.get (varname);
+
+ if (!value && spec_undefvar_allowed)
+ value = varname;
+
if (!value)
fatal_error (input_location,
- "environment variable %qs not defined", argv[0]);
+ "environment variable %qs not defined", varname);
/* We have to escape every character of the environment variable so
they are not interpreted as active spec characters. A
[-- Attachment #3: Type: text/plain, Size: 2 bytes --]
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: prevent "undef var" errors on gcc --help or --version
2016-01-12 16:11 ` Olivier Hainque
@ 2016-01-12 16:14 ` Bernd Schmidt
2016-01-12 16:37 ` Olivier Hainque
0 siblings, 1 reply; 5+ messages in thread
From: Bernd Schmidt @ 2016-01-12 16:14 UTC (permalink / raw)
To: Olivier Hainque; +Cc: GCC Patches
On 01/12/2016 05:11 PM, Olivier Hainque wrote:
> + /* Decide if undefined variable references are allowed in specs. */
> + {
> + /* --version and --help alone or together are safe. Note that -v would
> + make them unsafe, as they'd then be run for subprocesses as well, the
> + location of which might depend on variables possibly coming from
> + self-specs. */
> +
> + /* Count the number of options we have for which undefined variables
> + are harmless for sure, and check that nothing else is set. */
> +
> + unsigned n_varsafe_options = 0;
> +
I think you can do without the outer braces. Ok with those removed.
Bernd
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: prevent "undef var" errors on gcc --help or --version
2016-01-12 16:14 ` Bernd Schmidt
@ 2016-01-12 16:37 ` Olivier Hainque
0 siblings, 0 replies; 5+ messages in thread
From: Olivier Hainque @ 2016-01-12 16:37 UTC (permalink / raw)
To: Bernd Schmidt; +Cc: GCC Patches
> On 12 Jan 2016, at 17:14, Bernd Schmidt <bschmidt@redhat.com> wrote:
>
> I think you can do without the outer braces. Ok with those removed.
Great! Thanks for the review and comments.
With Kind Regards,
Olivier
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2016-01-12 16:37 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-01-08 13:23 prevent "undef var" errors on gcc --help or --version Olivier Hainque
2016-01-11 16:09 ` Bernd Schmidt
2016-01-12 16:11 ` Olivier Hainque
2016-01-12 16:14 ` Bernd Schmidt
2016-01-12 16:37 ` Olivier Hainque
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).