From 01ada12136c64ad9ff305f456637d43b9f6d4356 Mon Sep 17 00:00:00 2001 From: David Malcolm Date: Tue, 21 Nov 2017 00:40:53 +0000 Subject: [PATCH] C++: provide macro used-before-defined hint (PR c++/72786) 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. From-SVN: r254978 --- gcc/ChangeLog | 6 +++ gcc/cp/ChangeLog | 7 +++ gcc/cp/name-lookup.c | 50 ++++++++++++++++++- gcc/spellcheck.h | 7 +++ gcc/testsuite/ChangeLog | 7 +++ .../g++.dg/spellcheck-macro-ordering-2.C | 17 +++++++ .../g++.dg/spellcheck-macro-ordering.C | 3 +- libcpp/ChangeLog | 6 +++ libcpp/include/cpplib.h | 1 + libcpp/macro.c | 8 +++ 10 files changed, 109 insertions(+), 3 deletions(-) create mode 100644 gcc/testsuite/g++.dg/spellcheck-macro-ordering-2.C diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 4589f5bbdab..0255d8a3744 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2017-11-20 David Malcolm + + PR c++/72786 + * spellcheck.h (best_match::blithely_get_best_candidate): New + accessor. + 2017-11-20 Jakub Jelinek * config/i386/i386.c (parse_mtune_ctrl_str): Start diagnostics diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog index 5de732f5425..908b48ef09b 100644 --- a/gcc/cp/ChangeLog +++ b/gcc/cp/ChangeLog @@ -1,3 +1,10 @@ +2017-11-20 David Malcolm + + 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. + 2017-11-20 Jason Merrill * decl2.c (constrain_class_visibility): Don't warn about artificial diff --git a/gcc/cp/name-lookup.c b/gcc/cp/name-lookup.c index 9d97da383e7..fc317b175fb 100644 --- a/gcc/cp/name-lookup.c +++ b/gcc/cp/name-lookup.c @@ -5636,12 +5636,49 @@ consider_binding_level (tree name, best_match &bm, } } +/* Subclass of deferred_diagnostic. Notify the user that the + given macro was used before it was defined. + This can be done in the C++ frontend since tokenization happens + upfront. */ + +class macro_use_before_def : public deferred_diagnostic +{ + public: + /* Ctor. LOC is the location of the usage. MACRO is the + macro that was used. */ + macro_use_before_def (location_t loc, cpp_hashnode *macro) + : deferred_diagnostic (loc), m_macro (macro) + { + gcc_assert (macro); + } + + ~macro_use_before_def () + { + if (is_suppressed_p ()) + return; + + source_location def_loc = cpp_macro_definition_location (m_macro); + if (def_loc != UNKNOWN_LOCATION) + { + inform (get_location (), "the macro %qs had not yet been defined", + (const char *)m_macro->ident.str); + inform (def_loc, "it was later defined here"); + } + } + + private: + cpp_hashnode *m_macro; +}; + + /* Search for near-matches for NAME within the current bindings, and within macro names, returning the best match as a const char *, or NULL if - no reasonable match is found. */ + no reasonable match is found. + + Use LOC for any deferred diagnostics. */ name_hint -lookup_name_fuzzy (tree name, enum lookup_name_fuzzy_kind kind, location_t) +lookup_name_fuzzy (tree name, enum lookup_name_fuzzy_kind kind, location_t loc) { gcc_assert (TREE_CODE (name) == IDENTIFIER_NODE); @@ -5671,6 +5708,15 @@ lookup_name_fuzzy (tree name, enum lookup_name_fuzzy_kind kind, location_t) /* If a macro is the closest so far to NAME, consider it. */ if (best_macro) bm.consider ((const char *)best_macro->ident.str); + else if (bmm.get_best_distance () == 0) + { + /* If we have an exact match for a macro name, then the + macro has been used before it was defined. */ + cpp_hashnode *macro = bmm.blithely_get_best_candidate (); + if (macro) + return name_hint (NULL, + new macro_use_before_def (loc, macro)); + } /* Try the "starts_decl_specifier_p" keywords to detect "singed" vs "signed" typos. */ diff --git a/gcc/spellcheck.h b/gcc/spellcheck.h index 2edc695e632..bad3c1e2c37 100644 --- a/gcc/spellcheck.h +++ b/gcc/spellcheck.h @@ -178,6 +178,13 @@ class best_match return m_best_candidate; } + /* Get the closest candidate so far, without applying any filtering. */ + + candidate_t blithely_get_best_candidate () const + { + return m_best_candidate; + } + edit_distance_t get_best_distance () const { return m_best_distance; } size_t get_best_candidate_length () const { return m_best_candidate_len; } diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 05dd8e0f398..4c9569f13a9 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,10 @@ +2017-11-20 David Malcolm + + 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. + 2017-11-20 Steve Ellcey PR target/81356 diff --git a/gcc/testsuite/g++.dg/spellcheck-macro-ordering-2.C b/gcc/testsuite/g++.dg/spellcheck-macro-ordering-2.C new file mode 100644 index 00000000000..73c0f21ee45 --- /dev/null +++ b/gcc/testsuite/g++.dg/spellcheck-macro-ordering-2.C @@ -0,0 +1,17 @@ +// PR c++/72786 + +/* Example of undeffed macro. */ + +#define OVERRIDE override + +#undef OVERRIDE + +class DocTargetDriver { + virtual void clone() const OVERRIDE { } // { dg-line usage } + /* Offering "OVERRIDE" as a spelling suggestion for "OVERRIDE" would be + nonsensical. */ + // { dg-bogus "did you mean" "" { target *-*-* } usage } + // { dg-error "expected .;. at end of member declaration" "" { target *-*-* } usage } + // { dg-error ".OVERRIDE. does not name a type" "" { target *-*-* } usage } + // { dg-bogus "macro" "" { target *-*-* } usage } +}; diff --git a/gcc/testsuite/g++.dg/spellcheck-macro-ordering.C b/gcc/testsuite/g++.dg/spellcheck-macro-ordering.C index 3b888c6dcb3..bbd41f48e09 100644 --- a/gcc/testsuite/g++.dg/spellcheck-macro-ordering.C +++ b/gcc/testsuite/g++.dg/spellcheck-macro-ordering.C @@ -9,7 +9,8 @@ class DocTargetDriver { // { dg-bogus "did you mean" "" { target *-*-* } .-3 } // { dg-error "expected .;. at end of member declaration" "" { target *-*-* } .-4 } // { dg-error ".OVERRIDE. does not name a type" "" { target *-*-* } .-5 } + // { dg-message "the macro 'OVERRIDE' had not yet been defined" "" { target *-*-* } .-6 } }; #define OVERRIDE override - +// { dg-message "-:it was later defined here" "" { target *-*-* } .-1 } diff --git a/libcpp/ChangeLog b/libcpp/ChangeLog index 70c834c61d0..cc5d4d392c0 100644 --- a/libcpp/ChangeLog +++ b/libcpp/ChangeLog @@ -1,3 +1,9 @@ +2017-11-20 David Malcolm + + PR c++/72786 + * include/cpplib.h (cpp_macro_definition_location): New decl. + * macro.c (cpp_macro_definition): New function. + 2017-11-13 Tom Tromey * pch.c (cpp_read_state): Set n__VA_OPT__. diff --git a/libcpp/include/cpplib.h b/libcpp/include/cpplib.h index 101b33aef48..4d04a48a0e4 100644 --- a/libcpp/include/cpplib.h +++ b/libcpp/include/cpplib.h @@ -889,6 +889,7 @@ extern const cpp_token *cpp_get_token_with_location (cpp_reader *, extern bool cpp_fun_like_macro_p (cpp_hashnode *); extern const unsigned char *cpp_macro_definition (cpp_reader *, cpp_hashnode *); +extern source_location cpp_macro_definition_location (cpp_hashnode *); extern void _cpp_backup_tokens (cpp_reader *, unsigned int); extern const cpp_token *cpp_peek_token (cpp_reader *, int); diff --git a/libcpp/macro.c b/libcpp/macro.c index bf473eae358..43f2baa67b3 100644 --- a/libcpp/macro.c +++ b/libcpp/macro.c @@ -3646,3 +3646,11 @@ cpp_macro_definition (cpp_reader *pfile, cpp_hashnode *node) *buffer = '\0'; return pfile->macro_buffer; } + +/* Get the line at which the macro was defined. */ + +source_location +cpp_macro_definition_location (cpp_hashnode *node) +{ + return node->value.macro->line; +} -- 2.30.2