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.
---
gcc/cp/name-lookup.c | 47 +++++++++++++++++++++-
gcc/spellcheck.h | 7 ++++
gcc/testsuite/g++.dg/spellcheck-macro-ordering-2.C | 17 ++++++++
gcc/testsuite/g++.dg/spellcheck-macro-ordering.C | 3 +-
libcpp/include/cpplib.h | 1 +
libcpp/macro.c | 8 ++++
6 files changed, 80 insertions(+), 3 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/spellcheck-macro-ordering-2.C
diff --git a/gcc/cp/name-lookup.c b/gcc/cp/name-lookup.c
index de8c267..93bea35 100644
--- a/gcc/cp/name-lookup.c
+++ b/gcc/cp/name-lookup.c
@@ -4952,12 +4952,46 @@ consider_binding_level (tree name, best_match <tree,
const char *> &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);
+ }
+
+ void emit () OVERRIDE FINAL
+ {
+ 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);
@@ -4987,6 +5021,15 @@ 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 2edc695..bad3c1e 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/g++.dg/spellcheck-macro-ordering-2.C
b/gcc/testsuite/g++.dg/spellcheck-macro-ordering-2.C
new file mode 100644
index 0000000..73c0f21
--- /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 3b888c6..a2c7bba 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/include/cpplib.h b/libcpp/include/cpplib.h
index b843992..cf2fdc6 100644
--- a/libcpp/include/cpplib.h
+++ b/libcpp/include/cpplib.h
@@ -876,6 +876,7 @@ 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 de18c22..16fdd2a 100644
--- a/libcpp/macro.c
+++ b/libcpp/macro.c
@@ -3472,3 +3472,11 @@ 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;
+}
--
1.8.5.3
