If the declaration of an identifier has block scope, and the identifier has
external or internal linkage, the declaration shall have no initializer for
the identifier.
Clang now gives a more suitable diagnosis for this case.
Fixes https://github.com/llvm/llvm-project/issues/57478
Signed-off-by: Jun Zhang <jun@junz.org>
Differential Revision: https://reviews.llvm.org/D133088
Clang has traditionally allowed C programs to implicitly convert
integers to pointers and pointers to integers, despite it not being
valid to do so except under special circumstances (like converting the
integer 0, which is the null pointer constant, to a pointer). In C89,
this would result in undefined behavior per 3.3.4, and in C99 this rule
was strengthened to be a constraint violation instead. Constraint
violations are most often handled as an error.
This patch changes the warning to default to an error in all C modes
(it is already an error in C++). This gives us better security posture
by calling out potential programmer mistakes in code but still allows
users who need this behavior to use -Wno-error=int-conversion to retain
the warning behavior, or -Wno-int-conversion to silence the diagnostic
entirely.
Differential Revision: https://reviews.llvm.org/D129881
Based on post-commit review discussion on
2bd8493847 with Richard Smith.
Other uses of forcing HasEmptyPlaceHolder to false seem OK to me -
they're all around pointer/reference types where the pointer/reference
token will appear at the rightmost side of the left side of the type
name, so they make nested types (eg: the "int" in "int *") behave as
though there is a non-empty placeholder (because the "*" is essentially
the placeholder as far as the "int" is concerned).
This was originally committed in 277623f4d5
Reverted in f9ad1d1c77 due to breakages
outside of clang - lldb seems to have some strange/strong dependence on
"char [N]" versus "char[N]" when printing strings (not due to that name
appearing in DWARF, but probably due to using clang to stringify type
names) that'll need to be addressed, plus a few other odds and ends in
other subprojects (clang-tools-extra, compiler-rt, etc).
Looks like lldb has some issues with this - somehow it causes lldb to
treat a "char[N]" type as an array of chars (prints them out
individually) but a "char [N]" is printed as a string. (even though the
DWARF doesn't have this string in it - it's something to do with the
string lldb generates for itself using clang)
This reverts commit 277623f4d5.
Based on post-commit review discussion on
2bd8493847 with Richard Smith.
Other uses of forcing HasEmptyPlaceHolder to false seem OK to me -
they're all around pointer/reference types where the pointer/reference
token will appear at the rightmost side of the left side of the type
name, so they make nested types (eg: the "int" in "int *") behave as
though there is a non-empty placeholder (because the "*" is essentially
the placeholder as far as the "int" is concerned).
I have a follow-on patch that uses an alternative wording for
ext_excess_initializers in some cases. This patch puts it and
a couple of related warnings under their own -W option in order
to avoid a regression in Misc/warning-flags.c.
Differential Revision: https://reviews.llvm.org/D79244
This is long-since overdue, and matches GCC 5.0. This should also be
backwards-compatible, because we already supported all of C11 as an extension
in C99 mode.
llvm-svn: 220244
Moves the bool bail-out down a little in SemaChecking - so now
-Wnull-conversion and -Wliteral-conversion can fire when the target type is
bool.
Also improve the wording/details in the -Wliteral-conversion warning to match
the -Wconstant-conversion.
llvm-svn: 156826
This diagnostic seems to be production ready, it's just an oversight that it
wasn't turned on by default.
The test changes are a bit of a mixed bag. Some tests that seemed like they
clearly didn't need to use this behavior have been modified not to use it.
Others that I couldn't be sure about, I added the necessary expected-warnings
to.
It's possible the diagnostic message could be improved to make it clearer that
this warning can be suppressed by using a value that won't lose precision when
converted to the target type (but can still be a floating point literal, such
as "bool b = 1.0;").
llvm-svn: 154068
destination type for initialization, assignment, parameter-passing,
etc. The main issue fixed here is that we used rather confusing
wording for diagnostics such as
t.c:2:9: warning: initializing 'char const [2]' discards qualifiers,
expected 'char *' [-pedantic]
char *name = __func__;
^ ~~~~~~~~
We're not initializing a 'char const [2]', we're initializing a 'char
*' with an expression of type 'char const [2]'. Similar problems
existed for other diagnostics in this area, so I've normalized them all
with more precise descriptive text to say what we're
initializing/converting/assigning/etc. from and to. The warning for
the code above is now:
t.c:2:9: warning: initializing 'char *' from an expression of type
'char const [2]' discards qualifiers [-pedantic]
char *name = __func__;
^ ~~~~~~~~
Fixes <rdar://problem/7447179>.
llvm-svn: 100832
small bug fixes in SemaInit, switch over SemaDecl to use it more often, and
change a bunch of diagnostics which are different with the new initialization
code.
llvm-svn: 91767
- This is designed to make it obvious that %clang_cc1 is a "test variable"
which is substituted. It is '%clang_cc1' instead of '%clang -cc1' because it
can be useful to redefine what gets run as 'clang -cc1' (for example, to set
a default target).
llvm-svn: 91446
This patch isn't quite ideal in that it eliminates the warning for
constructs like "int a = {1};", where the braces are in fact redundant.
However, that would have required a bunch of refactoring, and it's
much less likely to cause confusion compared to redundant nested braces.
llvm-svn: 71939
braces. We now build the appropriate fully-structured initializer list
for such things. Per PR3618, verified that we're getting the right
code generation.
llvm-svn: 67353
extension. The interaction with designated initializers is a
bit... interesting... but we follow GNU's lead and don't permit too
much crazy code in this area.
Also, make the "excess initializers" error message a bit more
informative.
Addresses PR2561: http://llvm.org/bugs/show_bug.cgi?id=2561
llvm-svn: 63785
The approach I've taken in this patch is relatively straightforward,
although the code itself is non-trivial. Essentially, as we process
an initializer list we build up a fully-explicit representation of the
initializer list, where each of the subobject initializations occurs
in order. Designators serve to "fill in" subobject initializations in
a non-linear way. The fully-explicit representation makes initializer
lists (both with and without designators) easy to grok for codegen and
later semantic analyses. We keep the syntactic form of the initializer
list linked into the AST for those clients interested in exactly what
the user wrote.
Known limitations:
- Designating a member of a union that isn't the first member may
result in bogus initialization (we warn about this)
- GNU array-range designators are not supported (we warn about this)
llvm-svn: 63242
is an array type not a pointer type. This requires updating some
diags that change and updating the code generator to handle the
proper form of strings.
llvm-svn: 46941
Jun Zhang