On 05/05/2017 11:51 AM, David Malcolm wrote:
> This patch uses the name_hint/deferred_diagnostic to provide
> a message in the C++ frontend if a macro is used before it is defined
> e.g.:
>
> test.c:6:24: error: expected ‘;’ at end of member declaration
> virtual void clone() const OVERRIDE { }
> ^~~~~
> ;
> test.c:6:30: error: ‘OVERRIDE’ does not name a type
> virtual void clone() const OVERRIDE { }
> ^~~~~~~~
> test.c:6:30: note: the macro ‘OVERRIDE’ had not yet been defined
> test.c:15:0: note: it was later defined here
> #define OVERRIDE override
>
> It's possible to do it from the C++ frontend as tokenization happens
> up-front (and hence the macro already exists when the above is parsed);
> I attempted to do it from the C frontend, but because the C frontend only
> tokenizes on-demand during parsing, the macro isn't known about until
> later.
>
> gcc/cp/ChangeLog:
> PR c++/72786
> * name-lookup.c (class macro_use_before_def): New class.
> (lookup_name_fuzzy): Detect macro that were used before being
> defined, and report them as such.
>
> gcc/ChangeLog:
> PR c++/72786
> * spellcheck.h (best_match::blithely_get_best_candidate): New
> accessor.
>
> gcc/testsuite/ChangeLog:
> PR c++/72786
> * g++.dg/spellcheck-macro-ordering-2.C: New test case.
> * g++.dg/spellcheck-macro-ordering.C: Add dg-message directives
> for macro used-before-defined.
>
> libcpp/ChangeLog:
> PR c++/72786
> * include/cpplib.h (cpp_macro_definition_location): New decl.
> * macro.c (cpp_macro_definition): New function.
This is fine once the prereq is approved.
jeff
