https://gcc.gnu.org/g:5336b63fe81029cfd790208fbc69a08c70b82b01
commit r15-5738-g5336b63fe81029cfd790208fbc69a08c70b82b01
Author: David Malcolm <dmalc...@redhat.com>
Date: Wed Nov 27 19:21:15 2024 -0500
C/C++: add fix-it hints for missing '&' and '*' (v5) [PR87850]
This patch adds a note with a fix-it hint to various
pointer-vs-non-pointer diagnostics, suggesting the addition of
a leading '&' or '*'.
For example, note the ampersand fix-it hint in the following:
demo.c: In function 'int main()':
demo.c:5:22: error: invalid conversion from 'pthread_key_t' {aka 'unsigned
int'}
to 'pthread_key_t*' {aka 'unsigned int*'} [-fpermissive]
5 | pthread_key_create(key, NULL);
| ^~~
| |
| pthread_key_t {aka unsigned int}
demo.c:5:22: note: possible fix: take the address with '&'
5 | pthread_key_create(key, NULL);
| ^~~
| &
In file included from demo.c:1:
/usr/include/pthread.h:1122:47: note: initializing argument 1 of
'int pthread_key_create(pthread_key_t*, void (*)(void*))'
1122 | extern int pthread_key_create (pthread_key_t *__key,
| ~~~~~~~~~~~~~~~^~~~~
gcc/c-family/ChangeLog:
PR c++/87850
* c-common.cc: Include "gcc-rich-location.h".
(maybe_emit_indirection_note): New function.
* c-common.h (maybe_emit_indirection_note): New decl.
(compatible_types_for_indirection_note_p): New decl.
gcc/c/ChangeLog:
PR c++/87850
* c-typeck.cc (compatible_types_for_indirection_note_p): New
function.
(convert_for_assignment): Call maybe_emit_indirection_note for
pointer vs non-pointer diagnostics.
gcc/cp/ChangeLog:
PR c++/87850
* call.cc (convert_like_real): Call maybe_emit_indirection_note
for "invalid conversion" diagnostic.
* typeck.cc (compatible_types_for_indirection_note_p): New
function.
gcc/testsuite/ChangeLog:
PR c++/87850
* c-c++-common/indirection-fixits.c: New test.
* g++.dg/template/error60.C: Add fix-it hint to expected output.
* g++.dg/template/error60a.C: Likewise.
Signed-off-by: David Malcolm <dmalc...@redhat.com>
Diff:
---
gcc/c-family/c-common.cc | 35 +++
gcc/c-family/c-common.h | 4 +
gcc/c/c-typeck.cc | 18 +-
gcc/cp/call.cc | 2 +
gcc/cp/typeck.cc | 8 +
gcc/testsuite/c-c++-common/indirection-fixits.c | 317 ++++++++++++++++++++++++
gcc/testsuite/g++.dg/template/error60.C | 5 +
gcc/testsuite/g++.dg/template/error60a.C | 5 +
8 files changed, 392 insertions(+), 2 deletions(-)
diff --git a/gcc/c-family/c-common.cc b/gcc/c-family/c-common.cc
index 7fcd978d95bc..721407157bc3 100644
--- a/gcc/c-family/c-common.cc
+++ b/gcc/c-family/c-common.cc
@@ -54,6 +54,7 @@ along with GCC; see the file COPYING3. If not see
#include "tree-vector-builder.h"
#include "vec-perm-indices.h"
#include "tree-pretty-print-markup.h"
+#include "gcc-rich-location.h"
cpp_reader *parse_in; /* Declared in c-pragma.h. */
@@ -9630,6 +9631,40 @@ maybe_suggest_missing_token_insertion (rich_location
*richloc,
}
}
+/* Potentially emit a note about likely missing '&' or '*',
+ depending on EXPR and EXPECTED_TYPE. */
+
+void
+maybe_emit_indirection_note (location_t loc,
+ tree expr, tree expected_type)
+{
+ gcc_assert (expr);
+ gcc_assert (expected_type);
+
+ tree actual_type = TREE_TYPE (expr);
+
+ /* Missing '&'. */
+ if (TREE_CODE (expected_type) == POINTER_TYPE
+ && compatible_types_for_indirection_note_p (actual_type,
+ TREE_TYPE (expected_type))
+ && lvalue_p (expr))
+ {
+ gcc_rich_location richloc (loc);
+ richloc.add_fixit_insert_before ("&");
+ inform (&richloc, "possible fix: take the address with %qs", "&");
+ }
+
+ /* Missing '*'. */
+ if (TREE_CODE (actual_type) == POINTER_TYPE
+ && compatible_types_for_indirection_note_p (TREE_TYPE (actual_type),
+ expected_type))
+ {
+ gcc_rich_location richloc (loc);
+ richloc.add_fixit_insert_before ("*");
+ inform (&richloc, "possible fix: dereference with %qs", "*");
+ }
+}
+
#if CHECKING_P
namespace selftest {
diff --git a/gcc/c-family/c-common.h b/gcc/c-family/c-common.h
index e07909673ce9..a323982ae26b 100644
--- a/gcc/c-family/c-common.h
+++ b/gcc/c-family/c-common.h
@@ -1697,6 +1697,10 @@ extern void maybe_add_include_fixit (rich_location *,
const char *, bool);
extern void maybe_suggest_missing_token_insertion (rich_location *richloc,
enum cpp_ttype token_type,
location_t prev_token_loc);
+extern void maybe_emit_indirection_note (location_t loc,
+ tree expr, tree expected_type);
+extern bool compatible_types_for_indirection_note_p (tree type1, tree type2);
+
extern tree braced_lists_to_strings (tree, tree);
#if CHECKING_P
diff --git a/gcc/c/c-typeck.cc b/gcc/c/c-typeck.cc
index f465123bfab0..e429ce9d1761 100644
--- a/gcc/c/c-typeck.cc
+++ b/gcc/c/c-typeck.cc
@@ -1438,6 +1438,14 @@ struct comptypes_data {
const struct tagged_tu_seen_cache* cache;
};
+/* C implementation of compatible_types_for_indirection_note_p. */
+
+bool
+compatible_types_for_indirection_note_p (tree type1, tree type2)
+{
+ return comptypes (type1, type2) == 1;
+}
+
/* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
or various other operations. Return 2 if they are compatible
but a warning may be needed if you use them together. */
@@ -8487,7 +8495,10 @@ convert_for_assignment (location_t location, location_t
expr_loc, tree type,
if (permerror_opt (&richloc, OPT_Wint_conversion,
"passing argument %d of %qE makes pointer "
"from integer without a cast", parmnum, rname))
- inform_for_arg (fundecl, expr_loc, parmnum, type, rhstype);
+ {
+ maybe_emit_indirection_note (expr_loc, rhs, type);
+ inform_for_arg (fundecl, expr_loc, parmnum, type, rhstype);
+ }
}
break;
case ic_assign:
@@ -8527,7 +8538,10 @@ convert_for_assignment (location_t location, location_t
expr_loc, tree type,
if (permerror_opt (&richloc, OPT_Wint_conversion,
"passing argument %d of %qE makes integer from "
"pointer without a cast", parmnum, rname))
- inform_for_arg (fundecl, expr_loc, parmnum, type, rhstype);
+ {
+ maybe_emit_indirection_note (expr_loc, rhs, type);
+ inform_for_arg (fundecl, expr_loc, parmnum, type, rhstype);
+ }
}
break;
case ic_assign:
diff --git a/gcc/cp/call.cc b/gcc/cp/call.cc
index 2179332fb9da..9fbc1602b0de 100644
--- a/gcc/cp/call.cc
+++ b/gcc/cp/call.cc
@@ -8584,6 +8584,8 @@ convert_like_internal (conversion *convs, tree expr, tree
fn, int argnum,
complained = permerror (&richloc,
"invalid conversion from %qH to %qI",
TREE_TYPE (expr), totype);
+ if (complained)
+ maybe_emit_indirection_note (loc, expr, totype);
}
if (convs->kind == ck_ref_bind)
expr = convert_to_reference (totype, expr, CONV_IMPLICIT,
diff --git a/gcc/cp/typeck.cc b/gcc/cp/typeck.cc
index 102a8ed131cf..6e7f5e8451ad 100644
--- a/gcc/cp/typeck.cc
+++ b/gcc/cp/typeck.cc
@@ -1686,6 +1686,14 @@ structural_comptypes (tree t1, tree t2, int strict)
return true;
}
+/* C++ implementation of compatible_types_for_indirection_note_p. */
+
+bool
+compatible_types_for_indirection_note_p (tree type1, tree type2)
+{
+ return same_type_p (type1, type2);
+}
+
/* Return true if T1 and T2 are related as allowed by STRICT. STRICT
is a bitwise-or of the COMPARE_* flags. */
diff --git a/gcc/testsuite/c-c++-common/indirection-fixits.c
b/gcc/testsuite/c-c++-common/indirection-fixits.c
new file mode 100644
index 000000000000..0a658edd238d
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/indirection-fixits.c
@@ -0,0 +1,317 @@
+/* { dg-options "-fdiagnostics-show-caret" } */
+
+void takes_int_ptr(int*);
+void takes_char_ptr(char*);
+void takes_int(int);
+int returns_int(void);
+
+int ivar;
+char cvar;
+int *int_ptr;
+char *char_ptr;
+
+void test_1 (void)
+{
+ takes_int_ptr(&ivar);
+ takes_int_ptr(int_ptr);
+ takes_char_ptr(&cvar);
+ takes_char_ptr(char_ptr);
+
+ ivar = 42;
+ cvar = 'b';
+ int_ptr = &ivar;
+ char_ptr = &cvar;
+}
+
+void test_2 (void)
+{
+ takes_int_ptr(ivar); /* { dg-error "" "" } */
+ /* { dg-message "possible fix: take the address with '&'" "" { target *-*-*
} .-1 } */
+
+ /* Expect an '&' fix-it hint. */
+ /* { dg-begin-multiline-output "" }
+ takes_int_ptr(ivar);
+ ^~~~
+ |
+ int
+ { dg-end-multiline-output "" } */
+ /* { dg-begin-multiline-output "" }
+ takes_int_ptr(ivar);
+ ^~~~
+ &
+ { dg-end-multiline-output "" } */
+ /* { dg-begin-multiline-output "" }
+ void takes_int_ptr(int*);
+ ^~~~
+ { dg-end-multiline-output "" } */
+}
+
+void test_3 (void)
+{
+ takes_int_ptr(cvar); /* { dg-error "" } */
+
+ /* Don't expect an '&' fix-it hint. */
+ /* { dg-begin-multiline-output "" }
+ takes_int_ptr(cvar);
+ ^~~~
+ |
+ char
+ { dg-end-multiline-output "" } */
+ /* { dg-begin-multiline-output "" }
+ void takes_int_ptr(int*);
+ ^~~~
+ { dg-end-multiline-output "" } */
+}
+
+void test_4 (void)
+{
+ takes_char_ptr(ivar); /* { dg-error "" } */
+
+ /* Don't expect an '&' fix-it hint. */
+ /* { dg-begin-multiline-output "" }
+ takes_char_ptr(ivar);
+ ^~~~
+ |
+ int
+ { dg-end-multiline-output "" } */
+ /* { dg-begin-multiline-output "" }
+ void takes_char_ptr(char*);
+ ^~~~~
+ { dg-end-multiline-output "" } */
+}
+
+void test_5 (void)
+{
+ takes_char_ptr(cvar); /* { dg-error "" } */
+
+ /* Expect an '&' fix-it hint. */
+ /* { dg-begin-multiline-output "" }
+ takes_char_ptr(cvar);
+ ^~~~
+ |
+ char
+ { dg-end-multiline-output "" } */
+ /* { dg-begin-multiline-output "" }
+ takes_char_ptr(cvar);
+ ^~~~
+ &
+ { dg-end-multiline-output "" } */
+ /* { dg-begin-multiline-output "" }
+ void takes_char_ptr(char*);
+ ^~~~~
+ { dg-end-multiline-output "" } */
+}
+
+void test_6 (void)
+{
+ takes_int(int_ptr); /* { dg-error "" } */
+ /* { dg-message "possible fix: dereference with '*'" "" { target *-*-* } .-1
} */
+
+ /* Expect a '*' fix-it hint. */
+ /* { dg-begin-multiline-output "" }
+ takes_int(int_ptr);
+ ^~~~~~~
+ |
+ int *
+ { dg-end-multiline-output "" { target c } } */
+ /* { dg-begin-multiline-output "" }
+ takes_int(int_ptr);
+ ^~~~~~~
+ |
+ int*
+ { dg-end-multiline-output "" { target c++ } } */
+ /* { dg-begin-multiline-output "" }
+ takes_int(int_ptr);
+ ^~~~~~~
+ *
+ { dg-end-multiline-output "" } */
+ /* { dg-begin-multiline-output "" }
+ void takes_int(int);
+ ^~~
+ { dg-end-multiline-output "" } */
+}
+
+void test_7 (void)
+{
+ takes_int(char_ptr); /* { dg-error "" } */
+
+ /* Don't expect a '*' fix-it hint. */
+ /* { dg-begin-multiline-output "" }
+ takes_int(char_ptr);
+ ^~~~~~~~
+ |
+ char *
+ { dg-end-multiline-output "" { target c } } */
+ /* { dg-begin-multiline-output "" }
+ takes_int(char_ptr);
+ ^~~~~~~~
+ |
+ char*
+ { dg-end-multiline-output "" { target c++ } } */
+ /* { dg-begin-multiline-output "" }
+ void takes_int(int);
+ ^~~
+ { dg-end-multiline-output "" } */
+}
+
+void test_8 (void)
+{
+ ivar = int_ptr; /* { dg-error "" } */
+
+ /* Expect a fix-it hint from the C++ FE, but not from C (due to missing
+ location). */
+ /* { dg-begin-multiline-output "" }
+ ivar = int_ptr;
+ ^~~~~~~
+ |
+ int*
+ { dg-end-multiline-output "" { target c++ } } */
+ /* { dg-begin-multiline-output "" }
+ ivar = int_ptr;
+ ^~~~~~~
+ *
+ { dg-end-multiline-output "" { target c++ } } */
+ /* { dg-begin-multiline-output "" }
+ ivar = int_ptr;
+ ^
+ { dg-end-multiline-output "" { target c } } */
+}
+
+void test_9 (void)
+{
+ cvar = int_ptr; /* { dg-error "" } */
+
+ /* Don't expect a '*' fix-it hint. */
+ /* { dg-begin-multiline-output "" }
+ cvar = int_ptr;
+ ^~~~~~~
+ |
+ int*
+ { dg-end-multiline-output "" { target c++ } } */
+ /* { dg-begin-multiline-output "" }
+ cvar = int_ptr;
+ ^
+ { dg-end-multiline-output "" { target c } } */
+}
+
+void test_10 (void)
+{
+ int_ptr = ivar; /* { dg-error "" } */
+
+ /* Expect a fix-it hint from the C++ FE, but not from C (due to missing
+ location). */
+ /* { dg-begin-multiline-output "" }
+ int_ptr = ivar;
+ ^~~~
+ |
+ int
+ { dg-end-multiline-output "" { target c++ } } */
+ /* { dg-begin-multiline-output "" }
+ int_ptr = ivar;
+ ^~~~
+ &
+ { dg-end-multiline-output "" { target c++ } } */
+ /* { dg-begin-multiline-output "" }
+ int_ptr = ivar;
+ ^
+ { dg-end-multiline-output "" { target c } } */
+}
+
+void test_11 (void)
+{
+ char_ptr = ivar; /* { dg-error "" } */
+
+ /* Don't expect a fix-it hint, due to mismatching types. */
+ /* { dg-begin-multiline-output "" }
+ char_ptr = ivar;
+ ^~~~
+ |
+ int
+ { dg-end-multiline-output "" { target c++ } } */
+ /* { dg-begin-multiline-output "" }
+ char_ptr = ivar;
+ ^
+ { dg-end-multiline-output "" { target c } } */
+}
+
+/* We shouldn't offer '&' fix-it hints for non-lvalues. */
+
+void test_12 (void)
+{
+ takes_int_ptr (returns_int ()); /* { dg-error "" } */
+
+ /* { dg-begin-multiline-output "" }
+ takes_int_ptr (returns_int ());
+ ^~~~~~~~~~~~~~
+ |
+ int
+ { dg-end-multiline-output "" { target c } } */
+ /* { dg-begin-multiline-output "" }
+ takes_int_ptr (returns_int ());
+ ~~~~~~~~~~~~^~
+ |
+ int
+ { dg-end-multiline-output "" { target c++ } } */
+ /* { dg-begin-multiline-output "" }
+ void takes_int_ptr(int*);
+ ^~~~
+ { dg-end-multiline-output "" } */
+}
+
+/* Ignore typedefs when offering fix-it hints. */
+
+typedef int typedef_int_t;
+typedef_int_t typedef_int_t_var;
+
+void test_13 (void)
+{
+ takes_int_ptr (typedef_int_t_var); /* { dg-error "" } */
+ /* { dg-message "possible fix: take the address with '&'" "" { target *-*-*
} .-1 } */
+
+ /* Expect an '&' fix-it hint. */
+ /* { dg-begin-multiline-output "" }
+ takes_int_ptr (typedef_int_t_var);
+ ^~~~~~~~~~~~~~~~~
+ |
+ typedef_int_t {aka int}
+ { dg-end-multiline-output "" } */
+ /* { dg-begin-multiline-output "" }
+ takes_int_ptr (typedef_int_t_var);
+ ^~~~~~~~~~~~~~~~~
+ &
+ { dg-end-multiline-output "" } */
+ /* { dg-begin-multiline-output "" }
+ void takes_int_ptr(int*);
+ ^~~~
+ { dg-end-multiline-output "" } */
+}
+
+enum foo
+{
+ FOO_0,
+ FOO_1,
+ FOO_2
+};
+
+void test_14 (void)
+{
+ enum foo f;
+ takes_int_ptr (f); /* { dg-error "" } */
+ /* We don't expect a fix-it hint here. */
+ /* { dg-begin-multiline-output "" }
+ takes_int_ptr (f);
+ ^
+ |
+ enum foo
+ { dg-end-multiline-output "" { target c } } */
+ /* { dg-begin-multiline-output "" }
+ takes_int_ptr (f);
+ ^
+ |
+ foo
+ { dg-end-multiline-output "" { target c++ } } */
+ /* { dg-begin-multiline-output "" }
+ void takes_int_ptr(int*);
+ ^~~~
+ { dg-end-multiline-output "" } */
+}
diff --git a/gcc/testsuite/g++.dg/template/error60.C
b/gcc/testsuite/g++.dg/template/error60.C
index 8c2139b207c4..7d578b166cb3 100644
--- a/gcc/testsuite/g++.dg/template/error60.C
+++ b/gcc/testsuite/g++.dg/template/error60.C
@@ -35,3 +35,8 @@ void usage ()
|
int
{ dg-end-multiline-output "" } */
+ /* { dg-begin-multiline-output "" }
+ my_pointer<Foo> ptr (val);
+ ^~~
+ &
+ { dg-end-multiline-output "" } */
diff --git a/gcc/testsuite/g++.dg/template/error60a.C
b/gcc/testsuite/g++.dg/template/error60a.C
index 9d0f170c18ba..41af458d3f07 100644
--- a/gcc/testsuite/g++.dg/template/error60a.C
+++ b/gcc/testsuite/g++.dg/template/error60a.C
@@ -44,3 +44,8 @@ void usage ()
|
int
{ dg-end-multiline-output "" } */
+ /* { dg-begin-multiline-output "" }
+ my_pointer<Foo> ptr (val);
+ ^~~
+ &
+ { dg-end-multiline-output "" } */
