(!HELP NEEDED) Where is the doc for the format strings in gcc (for example, %q+D, ...)

(!HELP NEEDED) Where is the doc for the format strings in gcc (for example, %q+D, ...)

[Qing Zhao]

Hi,

In GCC, there are many utility routines for reporting error, warning, or information, for example:

warning (0, "weak declaration of %q+D not supported", decl);
warning_at (stmtloc, OPT_Wmaybe_uninitialized,  "%qE may be used uninitialized", ptr));
inform (loc, "in a call to %qT declared with " "attribute %<%s%>", fntype, access_str);
error ("%qD is unavailable: %s", node, (const char *) msg);

There are format-strings inside them, “%q+D”, “%qE”, “%qT”, “%qD”, etc, where can I find a doc for the details of
These format-strings? Or which source files I should read to understand the details?

Thanks a lot for your help.

Qing

Re: (!HELP NEEDED) Where is the doc for the format strings in gcc (for example, %q+D, ...)

[Marek Polacek]

On Wed, Oct 20, 2021 at 03:49:09PM +0000, Qing Zhao via Gcc-patches wrote:
> Hi,
> 
> In GCC, there are many utility routines for reporting error, warning, or information, for example:
> 
> warning (0, "weak declaration of %q+D not supported", decl);
> warning_at (stmtloc, OPT_Wmaybe_uninitialized,  "%qE may be used uninitialized", ptr));
> inform (loc, "in a call to %qT declared with " "attribute %<%s%>", fntype, access_str);
> error ("%qD is unavailable: %s", node, (const char *) msg);
> 
> There are format-strings inside them, “%q+D”, “%qE”, “%qT”, “%qD”, etc, where can I find a doc for the details of
> These format-strings? Or which source files I should read to understand the details?

You can take a look at cp/error.c:

/* Called from output_format -- during diagnostic message processing --
   to handle C++ specific format specifier with the following meanings:
   %A   function argument-list.
   %C   tree code.
   %D   declaration.
   %E   expression.
   %F   function declaration.
   %H   type difference (from).
   %I   type difference (to).
   %L   language as used in extern "lang".
   %O   binary operator.
   %P   function parameter whose position is indicated by an integer.
   %Q   assignment operator.
   %S   substitution (template + args)
   %T   type.
   %V   cv-qualifier.
   %X   exception-specification.  */
static bool 
cp_printer (pretty_printer *pp, text_info *text, const char *spec,

or c/c-objc-common.c:

/* Called during diagnostic message formatting process to print a
   source-level entity onto BUFFER.  The meaning of the format specifiers
   is as follows:
   %D: a general decl,
   %E: an identifier or expression,
   %F: a function declaration,
   %T: a type.
   %V: a list of type qualifiers from a tree.
   %v: an explicit list of type qualifiers
   %#v: an explicit list of type qualifiers of a function type.

   Please notice when called, the `%' part was already skipped by the
   diagnostic machinery.  */
static bool
c_tree_printer (pretty_printer *pp, text_info *text, const char *spec,

Marek

Re: (!HELP NEEDED) Where is the doc for the format strings in gcc (for example, %q+D, ...)

[Qing Zhao]

Hi, Marek,

Thanks a lot for the information. 

Really helpful.

Qing

> On Oct 20, 2021, at 12:57 PM, Marek Polacek <polacek@redhat.com> wrote:
> 
> On Wed, Oct 20, 2021 at 03:49:09PM +0000, Qing Zhao via Gcc-patches wrote:
>> Hi,
>> 
>> In GCC, there are many utility routines for reporting error, warning, or information, for example:
>> 
>> warning (0, "weak declaration of %q+D not supported", decl);
>> warning_at (stmtloc, OPT_Wmaybe_uninitialized,  "%qE may be used uninitialized", ptr));
>> inform (loc, "in a call to %qT declared with " "attribute %<%s%>", fntype, access_str);
>> error ("%qD is unavailable: %s", node, (const char *) msg);
>> 
>> There are format-strings inside them, “%q+D”, “%qE”, “%qT”, “%qD”, etc, where can I find a doc for the details of
>> These format-strings? Or which source files I should read to understand the details?
> 
> You can take a look at cp/error.c:
> 
> /* Called from output_format -- during diagnostic message processing --
>   to handle C++ specific format specifier with the following meanings:
>   %A   function argument-list.
>   %C   tree code.
>   %D   declaration.
>   %E   expression.
>   %F   function declaration.
>   %H   type difference (from).
>   %I   type difference (to).
>   %L   language as used in extern "lang".
>   %O   binary operator.
>   %P   function parameter whose position is indicated by an integer.
>   %Q   assignment operator.
>   %S   substitution (template + args)
>   %T   type.
>   %V   cv-qualifier.
>   %X   exception-specification.  */
> static bool 
> cp_printer (pretty_printer *pp, text_info *text, const char *spec,
> 
> or c/c-objc-common.c:
> 
> /* Called during diagnostic message formatting process to print a
>   source-level entity onto BUFFER.  The meaning of the format specifiers
>   is as follows:
>   %D: a general decl,
>   %E: an identifier or expression,
>   %F: a function declaration,
>   %T: a type.
>   %V: a list of type qualifiers from a tree.
>   %v: an explicit list of type qualifiers
>   %#v: an explicit list of type qualifiers of a function type.
> 
>   Please notice when called, the `%' part was already skipped by the
>   diagnostic machinery.  */
> static bool
> c_tree_printer (pretty_printer *pp, text_info *text, const char *spec,
> 
> Marek
> 

Re: (!HELP NEEDED) Where is the doc for the format strings in gcc (for example, %q+D, ...)

[Eric Gallager]

On Wed, Oct 20, 2021 at 10:57 AM Marek Polacek via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> On Wed, Oct 20, 2021 at 03:49:09PM +0000, Qing Zhao via Gcc-patches wrote:
> > Hi,
> >
> > In GCC, there are many utility routines for reporting error, warning, or information, for example:
> >
> > warning (0, "weak declaration of %q+D not supported", decl);
> > warning_at (stmtloc, OPT_Wmaybe_uninitialized,  "%qE may be used uninitialized", ptr));
> > inform (loc, "in a call to %qT declared with " "attribute %<%s%>", fntype, access_str);
> > error ("%qD is unavailable: %s", node, (const char *) msg);
> >
> > There are format-strings inside them, “%q+D”, “%qE”, “%qT”, “%qD”, etc, where can I find a doc for the details of
> > These format-strings? Or which source files I should read to understand the details?
>
> You can take a look at cp/error.c:
>
> /* Called from output_format -- during diagnostic message processing --
>    to handle C++ specific format specifier with the following meanings:
>    %A   function argument-list.
>    %C   tree code.
>    %D   declaration.
>    %E   expression.
>    %F   function declaration.
>    %H   type difference (from).
>    %I   type difference (to).
>    %L   language as used in extern "lang".
>    %O   binary operator.
>    %P   function parameter whose position is indicated by an integer.
>    %Q   assignment operator.
>    %S   substitution (template + args)
>    %T   type.
>    %V   cv-qualifier.
>    %X   exception-specification.  */
> static bool
> cp_printer (pretty_printer *pp, text_info *text, const char *spec,
>
> or c/c-objc-common.c:
>
> /* Called during diagnostic message formatting process to print a
>    source-level entity onto BUFFER.  The meaning of the format specifiers
>    is as follows:
>    %D: a general decl,
>    %E: an identifier or expression,
>    %F: a function declaration,
>    %T: a type.
>    %V: a list of type qualifiers from a tree.
>    %v: an explicit list of type qualifiers
>    %#v: an explicit list of type qualifiers of a function type.
>
>    Please notice when called, the `%' part was already skipped by the
>    diagnostic machinery.  */
> static bool
> c_tree_printer (pretty_printer *pp, text_info *text, const char *spec,
>
> Marek
>

Note that this is bug 92435: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92435