fcloutier created this revision.
fcloutier added reviewers: NoQ, ahatanak, aaron.ballman.
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Herald added a project: clang.
It's not unusual to see functions like this:
void log(const char *fmt, ...) {
va_list ap;
va_start(ap, fmt);
NSLogv([NSString stringWithCString:fmt], ap);
va_end(ap);
}
Currently, such a function can't be annotated with `__attribute__((format))`.
It can't do `__attribute__((format(printf)))` because `printf` does not accept
the `%@` format specifier (while this function does support it) and it can't do
`__attribute__((format(NSString)))` because the format argument is not a
`NSString *`. It's not always reasonable to ask the owners of these functions
to change the type of the format argument as it can be an ABI-breaking change.
The only viable thing to do is to not annotate `log` at all, which precludes
using `-Wformat-nonliteral` (as it will trigger on the `NSLogv` line) and may
hide format bugs in users of `log`.
This patch allows all string types for all format kinds and leaves it up to the
user to convert the format string with a function that has the correct
`__attribute__((format_arg))` annotation. The example above can now be
annotated with `__attribute__((format(NSString, 1, 2)))` and pass
`-Wformat-nonliteral`, provided that `[NSString stringWithCString:]` is
modified to have `__attribute__((format_arg(1)))`.
It is still a diagnostic to mix format strings with different format styles, so
for instance you can't pass a `printf`-style format string to `[NSString
stringWithFormat:]` even if you've converted it to a `NSString *`:
void log(const char *fmt, ...) __attribute__((format(printf, 1, 2))) {
va_list ap;
va_start(ap, fmt);
NSLogv([NSString stringWithCString:fmt], ap); // warning: format string
is not a string literal [-Wformat-nonliteral]
va_end(ap);
}
rdar://89060618
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D125254
Files:
clang/include/clang/Basic/DiagnosticSemaKinds.td
clang/lib/Sema/SemaDeclAttr.cpp
clang/test/SemaObjC/format-strings-objc.m
Index: clang/test/SemaObjC/format-strings-objc.m
===================================================================
--- clang/test/SemaObjC/format-strings-objc.m
+++ clang/test/SemaObjC/format-strings-objc.m
@@ -60,8 +60,23 @@
}
// Check type validation
-extern void NSLog2(int format, ...) __attribute__((format(__NSString__, 1,
2))); // expected-error {{format argument not an NSString}}
-extern void CFStringCreateWithFormat2(int *format, ...)
__attribute__((format(CFString, 1, 2))); // expected-error {{format argument
not a CFString}}
+extern void NSLog2(int format, ...) __attribute__((format(__NSString__, 1,
2))); // expected-error {{format argument not a string type}}
+extern void CFStringCreateWithFormat2(int *format, ...)
__attribute__((format(CFString, 1, 2))); // expected-error {{format argument
not a string type}}
+
+// Check interoperability of strings
+extern void NSLog3(const char *, ...) __attribute__((format(__NSString__, 1,
2)));
+extern void CFStringCreateWithFormat3(const char *, ...)
__attribute__((format(__NSString__, 1, 2)));
+extern void printf2(NSString *format, ...) __attribute__((format(printf, 1,
2)));
+
+extern NSString *CStringToNSString(const char *)
__attribute__((format_arg(1)));
+
+void NSLog3(const char *fmt, ...) {
+ NSString *const nsFmt = CStringToNSString(fmt);
+ va_list ap;
+ va_start(ap, fmt);
+ NSLogv(nsFmt, ap);
+ va_end(ap);
+}
// <rdar://problem/7068334> - Catch use of long long with int arguments.
void rdar_7068334(void) {
Index: clang/lib/Sema/SemaDeclAttr.cpp
===================================================================
--- clang/lib/Sema/SemaDeclAttr.cpp
+++ clang/lib/Sema/SemaDeclAttr.cpp
@@ -3661,8 +3661,7 @@
(!Ty->isPointerType() ||
!Ty->castAs<PointerType>()->getPointeeType()->isCharType())) {
S.Diag(AL.getLoc(), diag::err_format_attribute_not)
- << "a string type" << IdxExpr->getSourceRange()
- << getFunctionOrMethodParamRange(D, 0);
+ << IdxExpr->getSourceRange() << getFunctionOrMethodParamRange(D, 0);
return;
}
Ty = getFunctionOrMethodResultType(D);
@@ -3862,27 +3861,13 @@
// make sure the format string is really a string
QualType Ty = getFunctionOrMethodParamType(D, ArgIdx);
- if (Kind == CFStringFormat) {
- if (!isCFStringType(Ty, S.Context)) {
- S.Diag(AL.getLoc(), diag::err_format_attribute_not)
- << "a CFString" << IdxExpr->getSourceRange()
- << getFunctionOrMethodParamRange(D, ArgIdx);
- return;
- }
- } else if (Kind == NSStringFormat) {
- // FIXME: do we need to check if the type is NSString*? What are the
- // semantics?
- if (!isNSStringType(Ty, S.Context, /*AllowNSAttributedString=*/true)) {
- S.Diag(AL.getLoc(), diag::err_format_attribute_not)
- << "an NSString" << IdxExpr->getSourceRange()
- << getFunctionOrMethodParamRange(D, ArgIdx);
- return;
- }
- } else if (!Ty->isPointerType() ||
- !Ty->castAs<PointerType>()->getPointeeType()->isCharType()) {
+ bool NotNSStringTy = !isNSStringType(Ty, S.Context, true);
+ if (NotNSStringTy &&
+ !isCFStringType(Ty, S.Context) &&
+ (!Ty->isPointerType() ||
+ !Ty->castAs<PointerType>()->getPointeeType()->isCharType())) {
S.Diag(AL.getLoc(), diag::err_format_attribute_not)
- << "a string type" << IdxExpr->getSourceRange()
- << getFunctionOrMethodParamRange(D, ArgIdx);
+ << IdxExpr->getSourceRange() << getFunctionOrMethodParamRange(D, ArgIdx);
return;
}
Index: clang/include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -3104,7 +3104,7 @@
"strftime format attribute requires 3rd parameter to be 0">;
def err_format_attribute_requires_variadic : Error<
"format attribute requires variadic function">;
-def err_format_attribute_not : Error<"format argument not %0">;
+def err_format_attribute_not : Error<"format argument not a string type">;
def err_format_attribute_result_not : Error<"function does not return %0">;
def err_format_attribute_implicit_this_format_string : Error<
"format attribute cannot specify the implicit this argument as the format "
Index: clang/test/SemaObjC/format-strings-objc.m
===================================================================
--- clang/test/SemaObjC/format-strings-objc.m
+++ clang/test/SemaObjC/format-strings-objc.m
@@ -60,8 +60,23 @@
}
// Check type validation
-extern void NSLog2(int format, ...) __attribute__((format(__NSString__, 1, 2))); // expected-error {{format argument not an NSString}}
-extern void CFStringCreateWithFormat2(int *format, ...) __attribute__((format(CFString, 1, 2))); // expected-error {{format argument not a CFString}}
+extern void NSLog2(int format, ...) __attribute__((format(__NSString__, 1, 2))); // expected-error {{format argument not a string type}}
+extern void CFStringCreateWithFormat2(int *format, ...) __attribute__((format(CFString, 1, 2))); // expected-error {{format argument not a string type}}
+
+// Check interoperability of strings
+extern void NSLog3(const char *, ...) __attribute__((format(__NSString__, 1, 2)));
+extern void CFStringCreateWithFormat3(const char *, ...) __attribute__((format(__NSString__, 1, 2)));
+extern void printf2(NSString *format, ...) __attribute__((format(printf, 1, 2)));
+
+extern NSString *CStringToNSString(const char *) __attribute__((format_arg(1)));
+
+void NSLog3(const char *fmt, ...) {
+ NSString *const nsFmt = CStringToNSString(fmt);
+ va_list ap;
+ va_start(ap, fmt);
+ NSLogv(nsFmt, ap);
+ va_end(ap);
+}
// <rdar://problem/7068334> - Catch use of long long with int arguments.
void rdar_7068334(void) {
Index: clang/lib/Sema/SemaDeclAttr.cpp
===================================================================
--- clang/lib/Sema/SemaDeclAttr.cpp
+++ clang/lib/Sema/SemaDeclAttr.cpp
@@ -3661,8 +3661,7 @@
(!Ty->isPointerType() ||
!Ty->castAs<PointerType>()->getPointeeType()->isCharType())) {
S.Diag(AL.getLoc(), diag::err_format_attribute_not)
- << "a string type" << IdxExpr->getSourceRange()
- << getFunctionOrMethodParamRange(D, 0);
+ << IdxExpr->getSourceRange() << getFunctionOrMethodParamRange(D, 0);
return;
}
Ty = getFunctionOrMethodResultType(D);
@@ -3862,27 +3861,13 @@
// make sure the format string is really a string
QualType Ty = getFunctionOrMethodParamType(D, ArgIdx);
- if (Kind == CFStringFormat) {
- if (!isCFStringType(Ty, S.Context)) {
- S.Diag(AL.getLoc(), diag::err_format_attribute_not)
- << "a CFString" << IdxExpr->getSourceRange()
- << getFunctionOrMethodParamRange(D, ArgIdx);
- return;
- }
- } else if (Kind == NSStringFormat) {
- // FIXME: do we need to check if the type is NSString*? What are the
- // semantics?
- if (!isNSStringType(Ty, S.Context, /*AllowNSAttributedString=*/true)) {
- S.Diag(AL.getLoc(), diag::err_format_attribute_not)
- << "an NSString" << IdxExpr->getSourceRange()
- << getFunctionOrMethodParamRange(D, ArgIdx);
- return;
- }
- } else if (!Ty->isPointerType() ||
- !Ty->castAs<PointerType>()->getPointeeType()->isCharType()) {
+ bool NotNSStringTy = !isNSStringType(Ty, S.Context, true);
+ if (NotNSStringTy &&
+ !isCFStringType(Ty, S.Context) &&
+ (!Ty->isPointerType() ||
+ !Ty->castAs<PointerType>()->getPointeeType()->isCharType())) {
S.Diag(AL.getLoc(), diag::err_format_attribute_not)
- << "a string type" << IdxExpr->getSourceRange()
- << getFunctionOrMethodParamRange(D, ArgIdx);
+ << IdxExpr->getSourceRange() << getFunctionOrMethodParamRange(D, ArgIdx);
return;
}
Index: clang/include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -3104,7 +3104,7 @@
"strftime format attribute requires 3rd parameter to be 0">;
def err_format_attribute_requires_variadic : Error<
"format attribute requires variadic function">;
-def err_format_attribute_not : Error<"format argument not %0">;
+def err_format_attribute_not : Error<"format argument not a string type">;
def err_format_attribute_result_not : Error<"function does not return %0">;
def err_format_attribute_implicit_this_format_string : Error<
"format attribute cannot specify the implicit this argument as the format "
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