We have a new policy in place making links to private resources
something we try to avoid in source and test files. Normally, we'd
organically switch to the new policy rather than make a sweeping change
across a project. However, Clang is in a somewhat special circumstance
currently: recently, I've had several new contributors run into rdar
links around test code which their patch was changing the behavior of.
This turns out to be a surprisingly bad experience, especially for
newer folks, for a handful of reasons: not understanding what the link
is and feeling intimidated by it, wondering whether their changes are
actually breaking something important to a downstream in some way,
having to hunt down strangers not involved with the patch to impose on
them for help, accidental pressure from asking for potentially private
IP to be made public, etc. Because folks run into these links entirely
by chance (through fixing bugs or working on new features), there's not
really a set of problematic links to focus on -- all of the links have
basically the same potential for causing these problems. As a result,
this is an omnibus patch to remove all such links.
This was not a mechanical change; it was done by manually searching for
rdar, radar, radr, and other variants to find all the various
problematic links. From there, I tried to retain or reword the
surrounding comments so that we would lose as little context as
possible. However, because most links were just a plain link with no
supporting context, the majority of the changes are simple removals.
Differential Review: https://reviews.llvm.org/D158071
https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2350.htm made very
clear that it is an UB having type definitions with in offsetof.
Clang supports defining a type as the first argument as a conforming
extension due to how many projects use the construct in C99 and earlier
to calculate the alignment of a type. GCC also supports defining a type
as the first argument.
This adds extension warnings and documentation for the functionality
Clang explicitly supports.
Fixes#57065
Reverts the revert of 39da55e8f548a11f7dadefa73ea73d809a5f1729
Co-authored-by: Yingchi Long <i@lyc.dev>
Co-authored-by: Aaron Ballman <aaron@aaronballman.com>
Differential Revision: https://reviews.llvm.org/D133574
https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2350.htm made very
clear that it is an UB having type definitions with in offsetof.
Clang supports defining a type as the first argument as a conforming
extension due to how many projects use the construct in C99 and earlier
to calculate the alignment of a type. GCC also supports defining a type
as the first argument.
This adds extension warnings and documentation for the functionality
Clang explicitly supports.
Fixes#57065
Co-authored-by: Yingchi Long <i@lyc.dev>
Co-authored-by: Aaron Ballman <aaron@aaronballman.com>
This revision fixes typos where there are 2 consecutive words which are
duplicated. There should be no code changes in this revision (only
changes to comments and docs). Do let me know if there are any
undesirable changes in this revision. Thanks.
Post-commit feedback on https://reviews.llvm.org/D122895 pointed out
that the diagnostic wording for some code was using "declaration" in a
confusing way, such as:
int foo(); // warning: a function declaration without a prototype is deprecated in all versions of C and is not supported in C2x
int foo(int arg) { // warning: a function declaration without a prototype is deprecated in all versions of C and is not supported in C2x
return 5;
}
And that we had other minor issues with the diagnostics being somewhat
confusing.
This patch addresses the confusion by reworking the implementation to
be a bit more simple and a bit less chatty. Specifically, it changes
the warning and note diagnostics to be able to specify "declaration" or
"definition" as appropriate, and it changes the function merging logic
so that the function without a prototype is always what gets warned on,
and the function with a prototype is sometimes what gets noted.
Additionally, when diagnosing a K&R C definition that is preceded by a
function without a prototype, we don't note the prior declaration, we
warn on it because it will also be changing behavior in C2x.
Differential Revision: https://reviews.llvm.org/D125814
C89 allowed a type specifier to be elided with the resulting type being
int, aka implicit int behavior. This feature was subsequently removed
in C99 without a deprecation period, so implementations continued to
support the feature. Now, as with implicit function declarations, is a
good time to reevaluate the need for this support.
This patch allows -Wimplicit-int to issue warnings in C89 mode (off by
default), defaults the warning to an error in C99 through C17, and
disables support for the feature entirely in C2x. It also removes a
warning about missing declaration specifiers that really was just an
implicit int warning in disguise and other minor related cleanups.
Functions without prototypes in C (also known as K&R C functions) were
introduced into C89 as a deprecated feature and C2x is now reclaiming
that syntax space with different semantics. However, Clang's
-Wstrict-prototypes diagnostic is off-by-default (even in pedantic
mode) and does not suffice to warn users about issues in their code.
This patch changes the behavior of -Wstrict-prototypes to only diagnose
declarations and definitions which are not going to change behavior in
C2x mode, and enables the diagnostic in -pedantic mode. The diagnostic
is now specifically about the fact that the feature is deprecated.
It also adds -Wdeprecated-non-prototype, which is grouped under
-Wstrict-prototypes and diagnoses declarations or definitions which
will change behavior in C2x mode. This diagnostic is enabled by default
because the risk is higher for the user to continue to use the
deprecated feature.
Differential Revision: https://reviews.llvm.org/D122895
feature is c11 about nested struct declarations must have
struct-declarator-list. Without this change, code
which was meant for c99 breaks. rdar://18125536
llvm-svn: 216469
We had two bugs:
- We wouldn't properly warn when a struct/union/enum was mentioned
inside of a record definition if no declarator was provided. We
should have mentioned that this declaration declares nothing.
- We didn't properly support Microsoft's extension where certain
declspecs without declarators would act as anonymous structs/unions.
* We completely ignored the case where such a declspec could be a
union.
* We didn't properly handle the case where a record was defined inside
another record:
struct X {
int a;
struct Y {
int b;
};
};
llvm-svn: 215347
Array declarators involving the static keyword take on two forms:
D[ static type-qualifier-listopt assignment-expression ]
D[ type-qualifier-list static assignment-expression ]
Raise a diagnostic if the assignment-expression is missing.
This fixes PR20584.
llvm-svn: 215187
void knrNoSemi(i) int i { }
Adherents of The C Programming Language unfortunate enough to miss a semicolon
as above would be met with a cascade of errors spanning the remainder of the
TU.
This patch introduces a beautiful parse error recovery, complete with helpful
FixIt to restore sanity.
Before (output redacted for brevity):
error: 'error' diagnostics seen but not expected:
File declarators.c Line 119: declaration does not declare a parameter
File declarators.c Line 123: declaration does not declare a parameter
File declarators.c Line 127: parameter named 'func_E12' is missing
File declarators.c Line 127: expected ';' at end of declaration
File declarators.c Line 133: parameter named 'func_E13' is missing
File declarators.c Line 133: expected ';' at end of declaration
File declarators.c Line 139: parameter named 'func_E14' is missing
File declarators.c Line 139: expected ';' at end of declaration
File declarators.c Line 145: parameter named 'func_E15' is missing
File declarators.c Line 145: expected ';' at end of declaration
File declarators.c Line 150: expected function body after function declarator
File declarators.c Line 119: declaration of 'enum E11' will not be visible outside of this function
File declarators.c Line 123: declaration of 'enum E12' will not be visible outside of this function
File declarators.c Line 133: ISO C forbids forward references to 'enum' types
File declarators.c Line 133: declaration of 'enum E13' will not be visible outside of this function
File declarators.c Line 139: ISO C forbids forward references to 'enum' types
File declarators.c Line 139: declaration of 'enum E14' will not be visible outside of this function
File declarators.c Line 145: ISO C forbids forward references to 'enum' types
File declarators.c Line 145: declaration of 'enum E15' will not be visible outside of this function
...
After:
declarators.c:103:24: error: expected ';' at end of declaration
void knrNoSemi(i) int i { }
^
;
Patch found in a sealed envelope dated 1978 with the message "Do not open until
January 2014"
llvm-svn: 198540
Previously any error in enum definition body stopped parsing it. With this
change parser tries to recover from errors.
The patch fixes PR10982.
Differential Revision: http://llvm-reviews.chandlerc.com/D2018
llvm-svn: 198259
us to improve this diagnostic (telling us to insert another ")":
t.c:2:19: error: expected ';' at end of declaration
int x = 4+(5-12));
^
;
to:
t.c:2:19: error: extraneous ')' before ';'
int x = 4+(5-12));
^
...telling us to remove the ")". This is PR12595. There are more uses of ExpectAndConsumeSemi
that could be switched over, but I don't hit them on a daily basis :)
llvm-svn: 155759
In a few cases clang emitted a rather content-free diagnostic: 'parse error'.
This change replaces two actual cases (template parameter parsing and K&R
parameter declaration parsing) with more specific diagnostics and removes a
third dead case of this in the BalancedDelimiterTracker (the ctor already
checked the invariant necessary to ensure that the diag::parse_error was never
actually used).
llvm-svn: 154224
a function prototype is followed by a declarator if we
aren't parsing a K&R style identifier list.
Also, avoid skipping randomly after a declaration if a
semicolon is missing. Before we'd get:
t.c:3:1: error: expected function body after function declarator
void bar();
^
Now we get:
t.c:1:11: error: invalid token after top level declarator
void foo()
^
;
llvm-svn: 108105
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
or that's been hidden by a non-type (in C++).
The ideal C++ diagnostic here would note the hiding declaration, but this
is a good start.
llvm-svn: 96141
t.c:4:3: error: expected ';' at end of declaration list
int y;
^
t.c:4:8: warning: extra ';' inside a struct or union
int y;
^
t.c:6:1: warning: expected ';' at end of declaration list
};
^
After:
t.c:3:8: error: expected ';' at end of declaration list
int x // expected-error {{expected ';' at end of declaration list}}
^
;
t.c:5:8: warning: expected ';' at end of declaration list
int z
^
;
llvm-svn: 95038
- 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
scheme to be more useful.
The new scheme introduces a set of categories that should be more
readable, and also reflects what we want to consider as an extension
more accurately. Specifically, it makes the "what is a keyword"
determination accurately reflect whether the keyword is a GNU or
Microsoft extension.
I also introduced separate flags for keyword aliases; this is useful
because the classification of the aliases is mostly unrelated to the
classification of the original keyword.
This patch treats anything that's in the implementation
namespace (prefixed with "__", or "_X" where "X" is any upper-case
letter) as a keyword without marking it as an extension. This is
consistent with the standards in that an implementation is allowed to define
arbitrary extensions in the implementation namespace without violating
the standard. This gets rid of all the nasty "extension used" warnings
for stuff like __attribute__ in -pedantic mode. We still warn for
extensions outside of the the implementation namespace, like typeof.
If someone wants to implement -Wextensions or something like that, we
could add additional information to the keyword table.
This also removes processing for the unused "Boolean" language option;
such an extension isn't supported on any other C implementation, so I
don't see any point to adding it.
The changes to test/CodeGen/inline.c are required because previously, we
weren't actually disabling the "inline" keyword in -std=c89 mode.
I'll remove Boolean and NoExtensions from LangOptions in a follow-up
commit.
llvm-svn: 70281
struct xyz { int y; };
enum abc { ZZZ };
static xyz b;
abc c;
we used to produce:
t2.c:4:8: error: unknown type name 'xyz'
static xyz b;
^
t2.c:5:1: error: unknown type name 'abc'
abc c;
^
we now produce:
t2.c:4:8: error: use of tagged type 'xyz' without 'struct' tag
static xyz b;
^
struct
t2.c:5:1: error: use of tagged type 'abc' without 'enum' tag
abc c;
^
enum
GCC produces the normal:
t2.c:4: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘b’
t2.c:5: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘c’
rdar://6783347
llvm-svn: 68914
which tries to do better error recovery when it is "obvious" that an
identifier is a mis-typed typename. In this case, we try to parse
it as a typename instead of as the identifier in a declarator, which
gives us several options for better error recovery and immediately
makes diagnostics more useful. For example, we now produce:
t.c:4:8: error: unknown type name 'foo_t'
static foo_t a = 4;
^
instead of:
t.c:4:14: error: invalid token after top level declarator
static foo_t a = 4;
^
Also, since we now parse "a" correctly, we make a decl for it,
preventing later uses of 'a' from emitting things like:
t.c:12:20: error: use of undeclared identifier 'a'
int bar() { return a + b; }
^
I'd really appreciate any scrutiny possible on this, it
is a tricky area.
llvm-svn: 68911
