C89 had a questionable feature where the compiler would implicitly
declare a function that the user called but was never previously
declared. The resulting function would be globally declared as
extern int func(); -- a function without a prototype which accepts zero
or more arguments.
C99 removed support for this questionable feature due to severe
security concerns. However, there was no deprecation period; C89 had
the feature, C99 didn't. So Clang (and GCC) both supported the
functionality as an extension in C99 and later modes.
C2x no longer supports that function signature as it now requires all
functions to have a prototype, and given the known security issues with
the feature, continuing to support it as an extension is not tenable.
This patch changes the diagnostic behavior for the
-Wimplicit-function-declaration warning group depending on the language
mode in effect. We continue to warn by default in C89 mode (due to the
feature being dangerous to use). However, because this feature will not
be supported in C2x mode, we've diagnosed it as being invalid for so
long, the security concerns with the feature, and the trivial
workaround for users (declare the function), we now default the
extension warning to an error in C99-C17 mode. This still gives users
an easy workaround if they are extensively using the extension in those
modes (they can disable the warning or use -Wno-error to downgrade the
error), but the new diagnostic makes it more clear that this feature is
not supported and should be avoided. In C2x mode, we no longer allow an
implicit function to be defined and treat the situation the same as any
other lookup failure.
Differential Revision: https://reviews.llvm.org/D122983
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
This adds -no-opaque-pointers to clang tests whose output will
change when opaque pointers are enabled by default. This is
intended to be part of the migration approach described in
https://discourse.llvm.org/t/enabling-opaque-pointers-by-default/61322/9.
The patch has been produced by replacing %clang_cc1 with
%clang_cc1 -no-opaque-pointers for tests that fail with opaque
pointers enabled. Worth noting that this doesn't cover all tests,
there's a remaining ~40 tests not using %clang_cc1 that will need
a followup change.
Differential Revision: https://reviews.llvm.org/D123115
Without the fix ivars with anonymous types can trigger errors like
> error: 'TestClass::structIvar' from module 'Target' is not present in definition of 'TestClass' provided earlier
> [...]
> note: declaration of 'structIvar' does not match
It happens because types of ivars from different modules are considered
to be different. And it is caused by not merging anonymous `TagDecl`
from different modules.
To fix that I've changed `serialization::needsAnonymousDeclarationNumber`
to handle anonymous `TagDecl` inside `ObjCInterfaceDecl`. But that's not
sufficient as C code inside `ObjCInterfaceDecl` doesn't use interface
decl as a decl context but switches to its parent (TranslationUnit in
most cases). I'm changing that to make `ObjCContainerDecl` the lexical
decl context but keeping the semantic decl context intact.
Test "check-dup-decls-inside-objc.m" doesn't reflect a change in
functionality but captures the existing behavior to prevent regressions.
rdar://85563013
Differential Revision: https://reviews.llvm.org/D118525
The `objc_precise_lifetime` attribute is applied to Objective-C pointers to ensure the optimizer does not prematurely release an object under Automatic Reference Counting (ARC). It is a common enough pattern to assign values to these variables but not reference them otherwise, and annotating them with `__unused` is not really correct as they are being used to ensure an object's lifetime.
Differential Revision: https://reviews.llvm.org/D120372
This patch adds -Wno-strict-prototypes to all of the test cases that
use functions without prototypes, but not as the primary concern of the
test. e.g., attributes testing whether they can/cannot be applied to a
function without a prototype, etc.
This is done in preparation for enabling -Wstrict-prototypes by
default.
A significant number of our tests in C accidentally use functions
without prototypes. This patch converts the function signatures to have
a prototype for the situations where the test is not specific to K&R C
declarations. e.g.,
void func();
becomes
void func(void);
This is the final batch of tests being updated to add prototypes,
hopefully.
Previously, we would take a declaration like void f(void) and print it
as void f(). That's correct in C++ as far as it goes, but is incorrect
in C because that converts the function from having a prototype to one
which does not.
This turns out to matter for some of our tests that use the pretty
printer where we'd like to get rid of the K&R prototypes from the test
but can't because the test is checking the pretty printed function
signature, as done with the ARCMT tests.
A significant number of our tests in C accidentally use functions
without prototypes. This patch converts the function signatures to have
a prototype for the situations where the test is not specific to K&R C
declarations. e.g.,
void func();
becomes
void func(void);
This is the fourth batch of tests being updated (there are a significant
number of other tests left to be updated).
A significant number of our tests in C accidentally use functions
without prototypes. This patch converts the function signatures to have
a prototype for the situations where the test is not specific to K&R C
declarations. e.g.,
void func();
becomes
void func(void);
This is the third batch of tests being updated (there are a significant
number of other tests left to be updated).
Turning on `enable_noundef_analysis` flag allows better codegen by removing freeze instructions.
I modified clang by renaming `enable_noundef_analysis` flag to `disable-noundef-analysis` and turning it off by default.
Test updates are made as a separate patch: D108453
Reviewed By: eugenis
Differential Revision: https://reviews.llvm.org/D105169
If a class declares an instance property, and an inheritor class declares a class property with the same name, Clang Sema currently treats the latter as an overridden property, and compares the attributes of the two properties to check for a mismatch. The resulting diagnostics might be misleading, since neither of the properties actually overrides the another one.
rdar://86018435
Differential Revision: https://reviews.llvm.org/D116412
After 04f30795f1, -Wreturn-type has an effect on functions that
contain @try/@catch statements. CheckFallThrough() was missing
a case for ObjCAtTryStmts, leading to a false positive.
(What about the other two places in CheckFallThrough() that handle
CXXTryStmt but not ObjCAtTryStmts?
- I think the last use of CXXTryStmt is dead in practice: 04c6851cd made it so
that calls never add edges to try bodies, and the CFG block for a try
statement is always an empty block containing just the try element itself as
terminator (the try body itself is part of the normal flow of the function
and not connected to the block for the try statement itself. The try statment
cfg block is only connected to the catch bodies, and only reachable from
throw expressions within the try body.)
- The first use of CXXTryStmt might be important. It looks similar to
the code that adds all cfg blocks for try statements as roots of
the reachability graph for the reachability warnings, but I can't
find a way to trigger it. So I'm omitting it for now. The CXXTryStmt
code path seems to only be hit by try statements that are function
bodies without a surrounding compound statements
(`f() try { ... } catch ...`), and those don't exist for ObjC
@try statements.
)
Fixes PR52473.
Differential Revfision: https://reviews.llvm.org/D114660
[NFC] As part of using inclusive language within the llvm project, this patch
replaces `_myMaster` with `_myLeader` in these testcases.
Reviewed By: ZarkoCA
Differential Revision: https://reviews.llvm.org/D113433
* The format_arg attribute tells the compiler that the attributed function
returns a format string that is compatible with a format string that is being
passed as a specific argument.
* Several NSString methods return copies of their input, so they would ideally
have the format_arg attribute. A previous differential (D112670) added
support for instancetype methods having the format_arg attribute when used
in the context of NSString method declarations.
* D112670 failed to account that instancetype can be sugared in certain narrow
(but critical) scenarios, like by using nullability specifiers. This patch
resolves this problem.
Differential Revision: https://reviews.llvm.org/D113636
Reviewed By: ahatanak
Radar-Id: rdar://85278860
Turning on `enable_noundef_analysis` flag allows better codegen by removing freeze instructions.
I modified clang by renaming `enable_noundef_analysis` flag to `disable-noundef-analysis` and turning it off by default.
Test updates are made as a separate patch: D108453
Reviewed By: eugenis
Differential Revision: https://reviews.llvm.org/D105169
[Clang/Test]: Rename enable_noundef_analysis to disable-noundef-analysis and turn it off by default (2)
This patch updates test files after D105169.
Autogenerated test codes are changed by `utils/update_cc_test_checks.py,` and non-autogenerated test codes are changed as follows:
(1) I wrote a python script that (partially) updates the tests using regex: {F18594904} The script is not perfect, but I believe it gives hints about which patterns are updated to have `noundef` attached.
(2) The remaining tests are updated manually.
Reviewed By: eugenis
Differential Revision: https://reviews.llvm.org/D108453
Resolve lit failures in clang after 8ca4b3e's land
Fix lit test failures in clang-ppc* and clang-x64-windows-msvc
Fix missing failures in clang-ppc64be* and retry fixing clang-x64-windows-msvc
Fix internal_clone(aarch64) inline assembly
Turning on `enable_noundef_analysis` flag allows better codegen by removing freeze instructions.
I modified clang by renaming `enable_noundef_analysis` flag to `disable-noundef-analysis` and turning it off by default.
Test updates are made as a separate patch: D108453
Reviewed By: eugenis
Differential Revision: https://reviews.llvm.org/D105169
Trying to update some options that don't at least have an inclusive language version.
This patch adds `objcmt-allowlist-dir-path` as a default alternative.
Reviewed By: akyrtzi
Differential Revision: https://reviews.llvm.org/D112591
The __block Objective-C pointers can be set but not used due to a commonly used lifetime extension pattern in Objective-C.
Differential Revision: https://reviews.llvm.org/D112850
- [[format_arg(N)]] tells Clang that a method returns a format string with
specifiers equivalent to those passed in the string at argument #N. It
obviously requires the argument and the return type to be strings both.
- `instancetype` is a special return type available in Objective-C class
definitions that Clang expands to the most-derived statically known type on
use.
- In Objective-C mode, NSString is allowed in lieu of a C string, both as input
and output. However, _in the definition of NSString_, Clang rejects format_arg
on methods that return NSString. This PR addresses this issue by substituting
`instancetype` with the enclosing definition's type during the validation of
`format_arg`.
Reviewed By: ahatanak
Differential Revision: https://reviews.llvm.org/D112670
Radar-Id: rdar://84729746
@finally is still not implemented.
With this, clang can emit -Wreturn-type warnings for functions containing
@try/@catch (but not yet @finally), and -Wunreachable-code also works for those
functions.
The implementation is similar to D36914.
Part of PR46693.
Differential Revision: https://reviews.llvm.org/D112287
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).
This patch updates test files after D105169.
Autogenerated test codes are changed by `utils/update_cc_test_checks.py,` and non-autogenerated test codes are changed as follows:
(1) I wrote a python script that (partially) updates the tests using regex: {F18594904} The script is not perfect, but I believe it gives hints about which patterns are updated to have `noundef` attached.
(2) The remaining tests are updated manually.
Reviewed By: eugenis
Differential Revision: https://reviews.llvm.org/D108453
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).
There are functions where we do not want function instrumentation which is why we have `__attribute__((no_instrument_function))`. Extending this functionality to disable instrumentation for Objective-C methods as well. Objective C methods like `+load` run premain and having instrumentation on them causes runtime errors depending on the implementation of `__cyg_profile_func_enter` etc. functions
Reviewed By: rjmccall, aaron.ballman
Differential Revision: https://reviews.llvm.org/D111286
pointers to structs
clang was just being conservative and trying to prevent users from
messing up the qualifier on the inner pointer type. Lifting this
restriction enables using some of the libc++ templates with ObjC pointer
arguments, which clang currently rejects.
rdar://79018677
Differential Revision: https://reviews.llvm.org/D107021
This commit adds support for Mac Catalyst availability attribute, as
supported by the Apple clang compiler. A follow-up commit will provide
additional support for inferring Mac Catalyst availability from macOS
availability using the mapping in the SDKSettings.json.
Differential Revision: https://reviews.llvm.org/D105052
The anonymous and non-anonymous bit-field diagnostics are easily
combined into one diagnostic. However, the diagnostic was missing a
"the" that is present in the almost-identically worded
warn_bitfield_width_exceeds_type_width diagnostic, hence the changes to
test cases.
This fixes both https://bugs.llvm.org/show_bug.cgi?id=50309 and https://bugs.llvm.org/show_bug.cgi?id=50310.
Previously, lambdas inside functions would mark their own bodies for later analysis when encountering a potentially unavailable decl, without taking into consideration that the entire lambda itself might be correctly guarded inside an @available check. The same applied to inner class member functions. Blocks happened to work as expected already, since Sema::getEnclosingFunction() skips through block scopes.
This patch instead simply and conservatively marks the entire outermost function scope for search, and removes some special-case logic that prevented DiagnoseUnguardedAvailabilityViolations from traversing down into lambdas and nested functions. This correctly accounts for arbitrarily nested lambdas, inner classes, and blocks that may be inside appropriate @available checks at any ancestor level. It also treats all potential availability violations inside functions consistently, without being overly sensitive to the current DeclContext, which previously caused issues where e.g. nested struct members were warned about twice.
DiagnoseUnguardedAvailabilityViolations now has more work to do in some cases, particularly in functions with many (possibly deeply) nested lambdas and classes, but the big-O is the same, and the simplicity of the approach and the fact that it fixes at least two bugs feels like a strong win.
Differential Revision: https://reviews.llvm.org/D102338
when implementing an optional protocol requirement
When an Objective-C method implements an optional protocol requirement,
allow the method to use a newer introduced or older obsoleted
availability version than what's specified on the method in the protocol
itself. This allows SDK adopters to adopt an optional method from a
protocol later than when the method is introduced in the protocol. The users
that call an optional method on an object that conforms to this protocol
are supposed to check whether the object implements the method or not,
so a lack of appropriate `if (@available)` check for a new OS version
is not a cause of concern as there's already another runtime check that's required.
Differential Revision: https://reviews.llvm.org/D102459
These are intended to mimic warnings available in gcc.
-Wunused-but-set-variable is triggered in the case of a variable which
appears on the LHS of an assignment but not otherwise used.
For instance:
void f() {
int x;
x = 0;
}
-Wunused-but-set-parameter works similarly, but for function parameters
instead of variables.
In C++, they are triggered only for scalar types; otherwise, they are
triggered for all types. This is gcc's behavior.
-Wunused-but-set-parameter is controlled by -Wextra, while
-Wunused-but-set-variable is controlled by -Wunused. This is slightly
different from gcc's behavior, but seems most consistent with clang's
behavior for -Wunused-parameter and -Wunused-variable.
Reviewed By: aeubanks
Differential Revision: https://reviews.llvm.org/D100581
Programmers would like to be able to test direct methods by calling them from a
different linkage unit or mocking them, both of which are impossible. This
patch adds a flag that effectively disables the attribute, which will fix this
when enabled in testable builds. rdar://71190891
Differential revision: https://reviews.llvm.org/D95845
Aaron Ballman