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<base href="https://bugs.llvm.org/">
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<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - __attribute__((format_arg(X)) is broken with ObjC message sends"
href="https://bugs.llvm.org/show_bug.cgi?id=36599">36599</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>__attribute__((format_arg(X)) is broken with ObjC message sends
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>All
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>enhancement
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>Frontend
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>bhamiltoncx@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>I bisected this to <a href="https://reviews.llvm.org/D25820">https://reviews.llvm.org/D25820</a> / r284961 .
__attribute__((format_arg(X))) is supposed to mark a format argument as a
pass-through, but it no longer works with ObjC message sends.
Repro:
== apple clang-900.0.39.2: ok ==
% cat test.m
typedef unsigned int NSUInteger;
#define nil ((id)0)
@interface NSString
+ (id)stringWithFormat:(NSString *)fmt, ... __attribute__((format(__NSString__,
1, 2)));
@end
@interface NSBundle
- (NSString *)localizedStringForKey:(NSString *)key value:(nullable NSString
*)value table:(nullable NSString *)tableName __attribute__((format_arg(1)));
@end
#define NSLocalizedStringWithDefaultValue(key, tbl, bundle, val, comment) \
[bundle localizedStringForKey:(key) value:(val) table:(tbl)]
NSString *ShouldNotRaiseDataArgumentNotUsedByFormatString(NSUInteger count) {
return [NSString stringWithFormat:NSLocalizedStringWithDefaultValue(
@"foo",
@"",
nil,
@"%d",
@""),
count];
}
% clang --version
Apple LLVM version 9.0.0 (clang-900.0.39.2)
Target: x86_64-apple-darwin17.4.0
Thread model: posix
InstalledDir:
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin
% clang -fsyntax-only -Werror test.m && echo OK || echo NOT OK
OK
== r317698: bad ==
% clang --version
clang version 6.0.0 (trunk 317696) (llvm/trunk 317698)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /src/install/bin
% cat test.m
typedef unsigned int NSUInteger;
#define nil ((id)0)
@interface NSString
+ (id)stringWithFormat:(NSString *)fmt, ... __attribute__((format(__NSString__,
1, 2)));
@end
@interface NSBundle
- (NSString *)localizedStringForKey:(NSString *)key value:(nullable NSString
*)value table:(nullable NSString *)tableName __attribute__((format_arg(1)));
@end
#define NSLocalizedStringWithDefaultValue(key, tbl, bundle, val, comment) \
[bundle localizedStringForKey:(key) value:(val) table:(tbl)]
NSString *ShouldNotRaiseDataArgumentNotUsedByFormatString(NSUInteger count) {
return [NSString stringWithFormat:NSLocalizedStringWithDefaultValue(
@"foo",
@"",
nil,
@"%d",
@""),
count];
}
% clang -fsyntax-only -Werror test.m && echo OK || echo NOT OK
test.m:23:11: error: data argument not used by format string
[-Werror,-Wformat-extra-args]
count];
^
1 error generated.
NOT OK</pre>
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