Objective-C. Under a special flag, -Wcstring-format-directive,
off by default, issue a warning if %s directive is used in
certain CF/NS formatting APIs, to assist user in deprecating
use of such %s in these APIs. rdar://18182443
llvm-svn: 217467
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 435b951..0c3a3df 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -767,6 +767,37 @@
S.Diag(CallSiteLoc, diag::warn_null_arg) << ArgExpr->getSourceRange();
}
+/// \brief Diagnose use of %s directive in an NSString which is being passed
+/// as formatting string to formatting method.
+static void
+DiagnoseCStringFormatDirectiveInCFAPI(Sema &S,
+ const NamedDecl *FDecl,
+ Expr **Args,
+ unsigned NumArgs) {
+ if (NumArgs < 3)
+ return;
+ ObjCStringFormatFamily SFFamily = FDecl->getObjCFStringFormattingFamily();
+ if (SFFamily == ObjCStringFormatFamily::SFF_CFString) {
+ const Expr *FormatExpr = Args[2];
+ if (const CStyleCastExpr *CSCE = dyn_cast<CStyleCastExpr>(FormatExpr))
+ FormatExpr = CSCE->getSubExpr();
+ const StringLiteral *FormatString;
+ if (const ObjCStringLiteral *OSL =
+ dyn_cast<ObjCStringLiteral>(FormatExpr->IgnoreParenImpCasts()))
+ FormatString = OSL->getString();
+ else
+ FormatString = dyn_cast<StringLiteral>(FormatExpr->IgnoreParenImpCasts());
+ if (!FormatString)
+ return;
+ if (S.FormatStringHasSArg(FormatString)) {
+ S.Diag(FormatExpr->getExprLoc(), diag::warn_objc_cdirective_format_string)
+ << "%s" << 1 << 1;
+ S.Diag(FDecl->getLocation(), diag::note_entity_declared_at)
+ << FDecl->getDeclName();
+ }
+ }
+}
+
static void CheckNonNullArguments(Sema &S,
const NamedDecl *FDecl,
ArrayRef<const Expr *> Args,
@@ -899,6 +930,8 @@
return false;
CheckAbsoluteValueFunction(TheCall, FDecl, FnInfo);
+
+ DiagnoseCStringFormatDirectiveInCFAPI(*this, FDecl, Args, NumArgs);
unsigned CMId = FDecl->getMemoryFunctionKind();
if (CMId == 0)
@@ -3744,6 +3777,20 @@
} // TODO: handle other formats
}
+bool Sema::FormatStringHasSArg(const StringLiteral *FExpr) {
+ // Str - The format string. NOTE: this is NOT null-terminated!
+ StringRef StrRef = FExpr->getString();
+ const char *Str = StrRef.data();
+ // Account for cases where the string literal is truncated in a declaration.
+ const ConstantArrayType *T = Context.getAsConstantArrayType(FExpr->getType());
+ assert(T && "String literal not of constant array type!");
+ size_t TypeSize = T->getSize().getZExtValue();
+ size_t StrLen = std::min(std::max(TypeSize, size_t(1)) - 1, StrRef.size());
+ return analyze_format_string::ParseFormatStringHasSArg(Str, Str + StrLen,
+ getLangOpts(),
+ Context.getTargetInfo());
+}
+
//===--- CHECK: Warn on use of wrong absolute value function. -------------===//
// Returns the related absolute value function that is larger, of 0 if one