https://github.com/vvuksanovic updated https://github.com/llvm/llvm-project/pull/166738
>From aebddd9138b5aedd941739dcf5f8bf08357ad0b7 Mon Sep 17 00:00:00 2001 From: Vladimir Vuksanovic <[email protected]> Date: Fri, 31 Oct 2025 02:10:05 -0700 Subject: [PATCH 1/4] [Sema] Suggest missing format attributes Implements the `-Wmissing-format-attribute` diagnostic. It suggests adding format attributes to function declarations that call other format functions and pass the format string and arguments to them. Co-authored-by: Budimir Arandjelovic <[email protected]> --- clang/docs/ReleaseNotes.rst | 2 + clang/include/clang/Basic/DiagnosticGroups.td | 1 - .../clang/Basic/DiagnosticSemaKinds.td | 5 + clang/lib/Sema/SemaChecking.cpp | 125 ++++++++-- clang/lib/Sema/SemaDeclAttr.cpp | 4 +- clang/test/Sema/attr-format-missing.c | 217 ++++++++++++++++++ clang/test/Sema/attr-format-missing.cpp | 68 ++++++ 7 files changed, 397 insertions(+), 25 deletions(-) create mode 100644 clang/test/Sema/attr-format-missing.c create mode 100644 clang/test/Sema/attr-format-missing.cpp diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index 32f669f8d70d8..be384b7db72a3 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -401,6 +401,8 @@ Improvements to Clang's diagnostics or continue (#GH166013) - Clang now emits a diagnostic in case `vector_size` or `ext_vector_type` attributes are used with a negative size (#GH165463). +- Clang now detects potential missing format attributes on function declarations + when calling format functions. (#GH60718) Improvements to Clang's time-trace ---------------------------------- diff --git a/clang/include/clang/Basic/DiagnosticGroups.td b/clang/include/clang/Basic/DiagnosticGroups.td index 1e0321de3f4b6..7b534d416fdd9 100644 --- a/clang/include/clang/Basic/DiagnosticGroups.td +++ b/clang/include/clang/Basic/DiagnosticGroups.td @@ -607,7 +607,6 @@ def MainReturnType : DiagGroup<"main-return-type">; def MaxUnsignedZero : DiagGroup<"max-unsigned-zero">; def MissingBraces : DiagGroup<"missing-braces">; def MissingDeclarations: DiagGroup<"missing-declarations">; -def : DiagGroup<"missing-format-attribute">; def MissingIncludeDirs : DiagGroup<"missing-include-dirs">; def MissingNoreturn : DiagGroup<"missing-noreturn">; def MultiChar : DiagGroup<"multichar">; diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td index fa509536bf021..78c5caf79eab7 100644 --- a/clang/include/clang/Basic/DiagnosticSemaKinds.td +++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td @@ -3478,6 +3478,11 @@ 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 " "string">; +def warn_missing_format_attribute + : Warning<"diagnostic behavior may be improved by adding the '%0' format " + "attribute to the declaration of %1">, + InGroup<DiagGroup<"missing-format-attribute">>, + DefaultIgnore; def err_callback_attribute_no_callee : Error< "'callback' attribute specifies no callback callee">; def err_callback_attribute_invalid_callee : Error< diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp index ad2c2e4a97bb9..502e9fd099144 100644 --- a/clang/lib/Sema/SemaChecking.cpp +++ b/clang/lib/Sema/SemaChecking.cpp @@ -6517,7 +6517,8 @@ static StringLiteralCheckType checkFormatStringExpr( unsigned format_idx, unsigned firstDataArg, FormatStringType Type, VariadicCallType CallType, bool InFunctionCall, llvm::SmallBitVector &CheckedVarArgs, UncoveredArgHandler &UncoveredArg, - llvm::APSInt Offset, bool IgnoreStringsWithoutSpecifiers = false) { + llvm::APSInt Offset, std::optional<unsigned> *CallerParamIdx = nullptr, + bool IgnoreStringsWithoutSpecifiers = false) { if (S.isConstantEvaluatedContext()) return SLCT_NotALiteral; tryAgain: @@ -6542,7 +6543,7 @@ static StringLiteralCheckType checkFormatStringExpr( return checkFormatStringExpr( S, ReferenceFormatString, SLE, Args, APK, format_idx, firstDataArg, Type, CallType, /*InFunctionCall*/ false, CheckedVarArgs, - UncoveredArg, Offset, IgnoreStringsWithoutSpecifiers); + UncoveredArg, Offset, CallerParamIdx, IgnoreStringsWithoutSpecifiers); } return SLCT_NotALiteral; case Stmt::BinaryConditionalOperatorClass: @@ -6577,7 +6578,7 @@ static StringLiteralCheckType checkFormatStringExpr( Left = checkFormatStringExpr( S, ReferenceFormatString, C->getTrueExpr(), Args, APK, format_idx, firstDataArg, Type, CallType, InFunctionCall, CheckedVarArgs, - UncoveredArg, Offset, IgnoreStringsWithoutSpecifiers); + UncoveredArg, Offset, CallerParamIdx, IgnoreStringsWithoutSpecifiers); if (Left == SLCT_NotALiteral || !CheckRight) { return Left; } @@ -6586,7 +6587,7 @@ static StringLiteralCheckType checkFormatStringExpr( StringLiteralCheckType Right = checkFormatStringExpr( S, ReferenceFormatString, C->getFalseExpr(), Args, APK, format_idx, firstDataArg, Type, CallType, InFunctionCall, CheckedVarArgs, - UncoveredArg, Offset, IgnoreStringsWithoutSpecifiers); + UncoveredArg, Offset, CallerParamIdx, IgnoreStringsWithoutSpecifiers); return (CheckLeft && Left < Right) ? Left : Right; } @@ -6635,10 +6636,11 @@ static StringLiteralCheckType checkFormatStringExpr( if (InitList->isStringLiteralInit()) Init = InitList->getInit(0)->IgnoreParenImpCasts(); } - return checkFormatStringExpr( - S, ReferenceFormatString, Init, Args, APK, format_idx, - firstDataArg, Type, CallType, - /*InFunctionCall*/ false, CheckedVarArgs, UncoveredArg, Offset); + return checkFormatStringExpr(S, ReferenceFormatString, Init, Args, + APK, format_idx, firstDataArg, Type, + CallType, + /*InFunctionCall*/ false, CheckedVarArgs, + UncoveredArg, Offset, CallerParamIdx); } } @@ -6690,6 +6692,8 @@ static StringLiteralCheckType checkFormatStringExpr( // format arguments, in all cases. // if (const auto *PV = dyn_cast<ParmVarDecl>(VD)) { + if (CallerParamIdx) + *CallerParamIdx = PV->getFunctionScopeIndex(); if (const auto *D = dyn_cast<Decl>(PV->getDeclContext())) { for (const auto *PVFormatMatches : D->specific_attrs<FormatMatchesAttr>()) { @@ -6715,7 +6719,7 @@ static StringLiteralCheckType checkFormatStringExpr( S, ReferenceFormatString, PVFormatMatches->getFormatString(), Args, APK, format_idx, firstDataArg, Type, CallType, /*InFunctionCall*/ false, CheckedVarArgs, UncoveredArg, - Offset, IgnoreStringsWithoutSpecifiers); + Offset, CallerParamIdx, IgnoreStringsWithoutSpecifiers); } } @@ -6770,7 +6774,7 @@ static StringLiteralCheckType checkFormatStringExpr( StringLiteralCheckType Result = checkFormatStringExpr( S, ReferenceFormatString, Arg, Args, APK, format_idx, firstDataArg, Type, CallType, InFunctionCall, CheckedVarArgs, UncoveredArg, - Offset, IgnoreStringsWithoutSpecifiers); + Offset, CallerParamIdx, IgnoreStringsWithoutSpecifiers); if (IsFirst) { CommonResult = Result; IsFirst = false; @@ -6784,10 +6788,11 @@ static StringLiteralCheckType checkFormatStringExpr( if (BuiltinID == Builtin::BI__builtin___CFStringMakeConstantString || BuiltinID == Builtin::BI__builtin___NSStringMakeConstantString) { const Expr *Arg = CE->getArg(0); - return checkFormatStringExpr( - S, ReferenceFormatString, Arg, Args, APK, format_idx, - firstDataArg, Type, CallType, InFunctionCall, CheckedVarArgs, - UncoveredArg, Offset, IgnoreStringsWithoutSpecifiers); + return checkFormatStringExpr(S, ReferenceFormatString, Arg, Args, APK, + format_idx, firstDataArg, Type, CallType, + InFunctionCall, CheckedVarArgs, + UncoveredArg, Offset, CallerParamIdx, + IgnoreStringsWithoutSpecifiers); } } } @@ -6795,7 +6800,7 @@ static StringLiteralCheckType checkFormatStringExpr( return checkFormatStringExpr( S, ReferenceFormatString, SLE, Args, APK, format_idx, firstDataArg, Type, CallType, /*InFunctionCall*/ false, CheckedVarArgs, - UncoveredArg, Offset, IgnoreStringsWithoutSpecifiers); + UncoveredArg, Offset, CallerParamIdx, IgnoreStringsWithoutSpecifiers); return SLCT_NotALiteral; } case Stmt::ObjCMessageExprClass: { @@ -6821,7 +6826,7 @@ static StringLiteralCheckType checkFormatStringExpr( return checkFormatStringExpr( S, ReferenceFormatString, Arg, Args, APK, format_idx, firstDataArg, Type, CallType, InFunctionCall, CheckedVarArgs, UncoveredArg, - Offset, IgnoreStringsWithoutSpecifiers); + Offset, CallerParamIdx, IgnoreStringsWithoutSpecifiers); } } @@ -7001,6 +7006,77 @@ bool Sema::CheckFormatString(const FormatMatchesAttr *Format, return false; } +static void CheckMissingFormatAttributes(Sema *S, FormatStringType FormatType, + unsigned FormatIdx, unsigned FirstArg, + ArrayRef<const Expr *> Args, + Sema::FormatArgumentPassingKind APK, + unsigned CallerParamIdx, + SourceLocation Loc) { + const FunctionDecl *Caller = S->getCurFunctionDecl(); + if (!Caller) + return; + + // Find the offset to convert between attribute and parameter indexes. + unsigned CallerArgumentIndexOffset = + hasImplicitObjectParameter(Caller) ? 2 : 1; + + unsigned FirstArgumentIndex = -1; + switch (APK) { + case Sema::FormatArgumentPassingKind::FAPK_Fixed: + case Sema::FormatArgumentPassingKind::FAPK_Variadic: { + // As an extension, clang allows the format attribute on non-variadic + // functions. + // Caller must have fixed arguments to pass them to a fixed or variadic + // function. Try to match caller and callee arguments. If successful, then + // emit a diag with the caller idx, otherwise we can't determine the callee + // arguments. + unsigned NumCalleeArgs = Args.size() - FirstArg; + if (NumCalleeArgs == 0 || Caller->getNumParams() < NumCalleeArgs) { + // There aren't enough arugments in the caller to pass to callee. + return; + } + for (unsigned CalleeIdx = Args.size() - 1, + CallerIdx = Caller->getNumParams() - 1; + CalleeIdx >= FirstArg; --CalleeIdx, --CallerIdx) { + const auto *Arg = + dyn_cast<DeclRefExpr>(Args[CalleeIdx]->IgnoreParenCasts()); + if (!Arg) + return; + const auto *Param = dyn_cast<ParmVarDecl>(Arg->getDecl()); + if (!Param || Param->getFunctionScopeIndex() != CallerIdx) + return; + } + FirstArgumentIndex = + Caller->getNumParams() + CallerArgumentIndexOffset - NumCalleeArgs; + break; + } + case Sema::FormatArgumentPassingKind::FAPK_VAList: + // Caller arguments are either variadic or a va_list. + FirstArgumentIndex = + Caller->isVariadic() + ? (Caller->getNumParams() + CallerArgumentIndexOffset) + : 0; + break; + case Sema::FormatArgumentPassingKind::FAPK_Elsewhere: + // Args are not passed to the callee. + return; + } + + // Emit the diagnostic and fixit. + unsigned FormatStringIndex = CallerParamIdx + CallerArgumentIndexOffset; + StringRef FormatTypeName = S->GetFormatStringTypeName(FormatType); + S->Diag(Loc, diag::warn_missing_format_attribute) + << FormatTypeName << Caller + << FixItHint::CreateInsertion(Caller->getFirstDecl()->getLocation(), + (llvm::Twine("__attribute__((format(") + + FormatTypeName + ", " + + llvm::Twine(FormatStringIndex) + ", " + + llvm::Twine(FirstArgumentIndex) + ")))") + .str()); + S->Diag(Caller->getFirstDecl()->getLocation(), diag::note_callee_decl) + << Caller; +} + bool Sema::CheckFormatArguments(ArrayRef<const Expr *> Args, Sema::FormatArgumentPassingKind APK, const StringLiteral *ReferenceFormatString, @@ -7030,11 +7106,12 @@ bool Sema::CheckFormatArguments(ArrayRef<const Expr *> Args, // ObjC string uses the same format specifiers as C string, so we can use // the same format string checking logic for both ObjC and C strings. UncoveredArgHandler UncoveredArg; + std::optional<unsigned> CallerParamIdx; StringLiteralCheckType CT = checkFormatStringExpr( *this, ReferenceFormatString, OrigFormatExpr, Args, APK, format_idx, firstDataArg, Type, CallType, /*IsFunctionCall*/ true, CheckedVarArgs, UncoveredArg, - /*no string offset*/ llvm::APSInt(64, false) = 0); + /*no string offset*/ llvm::APSInt(64, false) = 0, &CallerParamIdx); // Generate a diagnostic where an uncovered argument is detected. if (UncoveredArg.hasUncoveredArg()) { @@ -7047,11 +7124,6 @@ bool Sema::CheckFormatArguments(ArrayRef<const Expr *> Args, // Literal format string found, check done! return CT == SLCT_CheckedLiteral; - // Strftime is particular as it always uses a single 'time' argument, - // so it is safe to pass a non-literal string. - if (Type == FormatStringType::Strftime) - return false; - // Do not emit diag when the string param is a macro expansion and the // format is either NSString or CFString. This is a hack to prevent // diag when using the NSLocalizedString and CFCopyLocalizedString macros @@ -7061,6 +7133,15 @@ bool Sema::CheckFormatArguments(ArrayRef<const Expr *> Args, SourceMgr.isInSystemMacro(FormatLoc)) return false; + if (CallerParamIdx) + CheckMissingFormatAttributes(this, Type, format_idx, firstDataArg, Args, + APK, *CallerParamIdx, Loc); + + // Strftime is particular as it always uses a single 'time' argument, + // so it is safe to pass a non-literal string. + if (Type == FormatStringType::Strftime) + return false; + // If there are no arguments specified, warn with -Wformat-security, otherwise // warn only with -Wformat-nonliteral. if (Args.size() == firstDataArg) { diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp index a9e7b44ac9d73..9849e125889cf 100644 --- a/clang/lib/Sema/SemaDeclAttr.cpp +++ b/clang/lib/Sema/SemaDeclAttr.cpp @@ -3572,7 +3572,7 @@ static void handleEnumExtensibilityAttr(Sema &S, Decl *D, } /// Handle __attribute__((format_arg((idx)))) attribute based on -/// http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html +/// https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html static void handleFormatArgAttr(Sema &S, Decl *D, const ParsedAttr &AL) { const Expr *IdxExpr = AL.getArgAsExpr(0); ParamIdx Idx; @@ -3771,7 +3771,7 @@ struct FormatAttrCommon { }; /// Handle __attribute__((format(type,idx,firstarg))) attributes based on -/// http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html +/// https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html static bool handleFormatAttrCommon(Sema &S, Decl *D, const ParsedAttr &AL, FormatAttrCommon *Info) { // Checks the first two arguments of the attribute; this is shared between diff --git a/clang/test/Sema/attr-format-missing.c b/clang/test/Sema/attr-format-missing.c new file mode 100644 index 0000000000000..7e5131153f661 --- /dev/null +++ b/clang/test/Sema/attr-format-missing.c @@ -0,0 +1,217 @@ +// RUN: %clang_cc1 -fsyntax-only -verify -Wmissing-format-attribute %s +// RUN: %clang_cc1 -fsyntax-only -Wmissing-format-attribute -fdiagnostics-parseable-fixits %s 2>&1 | FileCheck %s + +typedef unsigned long size_t; +typedef long ssize_t; +typedef __builtin_va_list va_list; + +__attribute__((format(printf, 1, 2))) +int printf(const char *, ...); + +__attribute__((format(scanf, 1, 2))) +int scanf(const char *, ...); + +__attribute__((format(printf, 1, 0))) +int vprintf(const char *, va_list); + +__attribute__((format(scanf, 1, 0))) +int vscanf(const char *, va_list); + +__attribute__((format(printf, 2, 0))) +int vsprintf(char *, const char *, va_list); + +struct tm { unsigned i; }; +__attribute__((format(strftime, 3, 0))) +size_t strftime(char *, size_t, const char *, const struct tm *); + +__attribute__((format(strfmon, 3, 4))) +ssize_t strfmon(char *, size_t, const char *, ...); + +// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:6-[[@LINE+1]]:6}:"__attribute__((format(printf, 1, 0)))" +void f1(char *out, va_list args) // #f1 +{ + vprintf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'printf' format attribute to the declaration of 'f1'}} + // expected-note@#f1 {{'f1' declared here}} +} + +// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:6-[[@LINE+1]]:6}:"__attribute__((format(scanf, 1, 0)))" +void f2(const char *out, va_list args) // #f2 +{ + vscanf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'scanf' format attribute to the declaration of 'f2'}} + // expected-note@#f2 {{'f2' declared here}} +} + +// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:6-[[@LINE+1]]:6}:"__attribute__((format(printf, 1, 2)))" +void f3(const char *out, ... /* args */) // #f3 +{ + va_list args; + vprintf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'printf' format attribute to the declaration of 'f3'}} + // expected-note@#f3 {{'f3' declared here}} +} + +// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:6-[[@LINE+1]]:6}:"__attribute__((format(scanf, 1, 2)))" +void f4(const char *out, ... /* args */) // #f4 +{ + va_list args; + vscanf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'scanf' format attribute to the declaration of 'f4'}} + // expected-note@#f4 {{'f4' declared here}} +} + +// CHECK: fix-it:"{{.*}}":{[[@LINE+2]]:6-[[@LINE+2]]:6}:"__attribute__((format(printf, 2, 3)))" +__attribute__((format(printf, 1, 3))) +void f5(char *out, const char *format, ... /* args */) // #f5 +{ + va_list args; + vsprintf(out, format, args); // expected-warning {{diagnostic behavior may be improved by adding the 'printf' format attribute to the declaration of 'f5'}} + // expected-note@#f5 {{'f5' declared here}} +} + +__attribute__((format(scanf, 1, 3))) +void f6(char *out, const char *format, ... /* args */) // #f6 +{ + va_list args; + vsprintf(out, format, args); // expected-warning {{diagnostic behavior may be improved by adding the 'printf' format attribute to the declaration of 'f6'}} + // expected-note@#f6 {{'f6' declared here}} +} + +// Ok, out is not passed to print functions. +void f7(char* out, ... /* args */) +{ + va_list args; + + const char *ch = "format"; + vprintf(ch, args); + vprintf("test", args); +} + +// Ok, out is not passed to print functions. +void f8(char *out, va_list args) +{ + const char *ch = "format"; + vprintf(ch, args); + vprintf("test", args); +} + +// Ok, out is not passed to scan functions. +void f9(va_list args) +{ + const char *ch = "format"; + vscanf(ch, args); + vscanf("test", args); +} + +// CHECK: fix-it:"{{.*}}":{[[@LINE+2]]:6-[[@LINE+2]]:6}:"__attribute__((format(scanf, 1, 2)))" +// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:6-[[@LINE+1]]:6}:"__attribute__((format(printf, 1, 2)))" +void f10(const char *out, ... /* args */) // #f10 +{ + va_list args; + vscanf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'scanf' format attribute to the declaration of 'f10'}} + // expected-note@#f10 {{'f10' declared here}} + vprintf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'printf' format attribute to the declaration of 'f10'}} + // expected-note@#f10 {{'f10' declared here}} +} + +// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:6-[[@LINE+1]]:6}:"__attribute__((format(printf, 1, 2)))" +void f11(const char out[], ... /* args */) // #f11 +{ + va_list args; + char ch[10] = "format"; + vprintf(ch, args); + vsprintf(ch, out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'printf' format attribute to the declaration of 'f11'}} + // expected-note@#f11 {{'f11' declared here}} +} + +// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:6-[[@LINE+1]]:6}:"__attribute__((format(printf, 1, 0)))" +void f12(char* out) // #f12 +{ + va_list args; + const char *ch = "format"; + vsprintf(out, ch, args); + vprintf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'printf' format attribute to the declaration of 'f12'}} + // expected-note@#f12 {{'f12' declared here}} +} + +// CHECK: fix-it:"{{.*}}":{[[@LINE+2]]:6-[[@LINE+2]]:6}:"__attribute__((format(scanf, 1, 2)))" +// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:6-[[@LINE+1]]:6}:"__attribute__((format(printf, 1, 2)))" +void f13(char *out, ... /* args */) // #f13 +{ + va_list args; + vscanf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'scanf' format attribute to the declaration of 'f13'}} + // expected-note@#f13 {{'f13' declared here}} + vprintf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'printf' format attribute to the declaration of 'f13'}} + // expected-note@#f13 {{'f13' declared here}} +} + +// CHECK: fix-it:"{{.*}}":{[[@LINE+2]]:6-[[@LINE+2]]:6}:"__attribute__((format(scanf, 1, 0)))" +// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:6-[[@LINE+1]]:6}:"__attribute__((format(printf, 1, 0)))" +void f14(char *out, va_list args) // #f14 +{ + vscanf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'scanf' format attribute to the declaration of 'f14'}} + // expected-note@#f14 {{'f14' declared here}} + vprintf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'printf' format attribute to the declaration of 'f14'}} + // expected-note@#f14 {{'f14' declared here}} +} + +// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:6-[[@LINE+1]]:6}:"__attribute__((format(scanf, 1, 2)))" +void f15(char *out, ... /* args */) // #f15 +{ + va_list args; + vscanf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'scanf' format attribute to the declaration of 'f15'}} + // expected-note@#f15 {{'f15' declared here}} + vscanf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'scanf' format attribute to the declaration of 'f15'}} + // expected-note@#f15 {{'f15' declared here}} +} + +// CHECK: fix-it:"{{.*}}":{[[@LINE+2]]:6-[[@LINE+2]]:6}:"__attribute__((format(printf, 1, 3)))" +// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:6-[[@LINE+1]]:6}:"__attribute__((format(printf, 2, 3)))" +void f16(char *ch, const char *out, ... /* args */) // #f16 +{ + va_list args; + vprintf(ch, args); // expected-warning {{diagnostic behavior may be improved by adding the 'printf' format attribute to the declaration of 'f16'}} + // expected-note@#f16 {{'f16' declared here}} + vprintf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'printf' format attribute to the declaration of 'f16'}} + // expected-note@#f16 {{'f16' declared here}} +} + +// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:6-[[@LINE+1]]:6}:"__attribute__((format(printf, 1, 2)))" +void f17(const char *a, ...) // #f17 +{ + va_list ap; + const char *const b = a; + vprintf(b, ap); // expected-warning {{diagnostic behavior may be improved by adding the 'printf' format attribute to the declaration of 'f17'}} + // expected-note@#f17 {{'f17' declared here}} +} + +// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:6-[[@LINE+1]]:6}:"__attribute__((format(printf, 1, 2)))" +void f18(char *fmt, unsigned x, unsigned y, unsigned z) // #f18 +{ + printf(fmt, x, y, z); // expected-warning {{diagnostic behavior may be improved by adding the 'printf' format attribute to the declaration of 'f18'}} + // expected-note@#f18 {{'f18' declared here}} +} + +void f19(char *fmt, unsigned x, unsigned y, unsigned z) // #f19 +{ + // Arguments are not passed in the same order. + printf(fmt, x, z, y); +} + +void f20(char *out, ... /* args */) +{ + printf(out, 1); // No warning, arguments are not passed to printf. +} + +// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:6-[[@LINE+1]]:6}:"__attribute__((format(strftime, 3, 0)))" +void f21(char *out, const size_t len, const char *format) // #f21 +{ + struct tm tm_arg; + tm_arg.i = 0; + strftime(out, len, format, &tm_arg); // expected-warning {{diagnostic behavior may be improved by adding the 'strftime' format attribute to the declaration of 'f21'}} + // expected-note@#f21 {{'f21' declared here}} +} + +// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:6-[[@LINE+1]]:6}:"__attribute__((format(strfmon, 3, 4)))" +void f22(char *out, const size_t len, const char *format, int x, int y) // #f22 +{ + strfmon(out, len, format, x, y); // expected-warning {{diagnostic behavior may be improved by adding the 'strfmon' format attribute to the declaration of 'f22'}} + // expected-note@#f22 {{'f22' declared here}} +} diff --git a/clang/test/Sema/attr-format-missing.cpp b/clang/test/Sema/attr-format-missing.cpp new file mode 100644 index 0000000000000..90d667531ce0a --- /dev/null +++ b/clang/test/Sema/attr-format-missing.cpp @@ -0,0 +1,68 @@ +// RUN: %clang_cc1 -fsyntax-only -verify -std=c++23 -Wmissing-format-attribute %s +// RUN: %clang_cc1 -fsyntax-only -Wmissing-format-attribute -fdiagnostics-parseable-fixits -std=c++23 %s 2>&1 | FileCheck %s + +typedef __SIZE_TYPE__ size_t; +typedef __builtin_va_list va_list; + +__attribute__((__format__(__printf__, 1, 2))) +int printf(const char *, ...); + +__attribute__((__format__(__scanf__, 1, 2))) +int scanf(const char *, ...); + +__attribute__((__format__(__printf__, 1, 0))) +int vprintf(const char *, va_list); + +__attribute__((__format__(__scanf__, 1, 0))) +int vscanf(const char *, va_list); + +__attribute__((__format__(__printf__, 2, 0))) +int vsprintf(char *, const char *, va_list); + +__attribute__((__format__(__printf__, 3, 0))) +int vsnprintf(char *, size_t, const char *, va_list); + +struct S1 +{ + // CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:8-[[@LINE+1]]:8}:"__attribute__((format(scanf, 2, 3)))" + void fn1(const char *out, ... /* args */) // #S1_fn1 + { + va_list args; + vscanf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'scanf' format attribute to the declaration of 'fn1'}} + // expected-note@#S1_fn1 {{'fn1' declared here}} + } + + __attribute__((format(printf, 2, 0))) + void print(const char *out, va_list args); + + // CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:8-[[@LINE+1]]:8}:"__attribute__((format(printf, 2, 3)))" + void fn2(const char *out, ... /* args */) // #S1_fn2 + { + va_list args; + print(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'printf' format attribute to the declaration of 'fn2'}} + // expected-note@#S1_fn2 {{'fn2' declared here}} + } + + // CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:8-[[@LINE+1]]:8}:"__attribute__((format(printf, 2, 0)))" + void fn3(const char *out, va_list args) // #S1_fn3 + { + print(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'printf' format attribute to the declaration of 'fn3'}} + // expected-note@#S1_fn3 {{'fn3' declared here}} + } + + // CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:8-[[@LINE+1]]:8}:"__attribute__((format(printf, 2, 3)))" + void fn4(this S1& self, const char *out, ... /* args */) // #S1_fn4 + { + va_list args; + self.print(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'printf' format attribute to the declaration of 'fn4'}} + // expected-note@#S1_fn4 {{'fn4' declared here}} + } + + // CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:8-[[@LINE+1]]:8}:"__attribute__((format(printf, 2, 0)))" + void fn5(this S1& self, const char *out, va_list args) // #S1_fn5 + { + self.print(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'printf' format attribute to the declaration of 'fn5'}} + // expected-note@#S1_fn5 {{'fn5' declared here}} + } +}; + >From c62ec642a3aafd82ae4ec1da0ea46d1a4ca43c60 Mon Sep 17 00:00:00 2001 From: Vladimir Vuksanovic <[email protected]> Date: Fri, 7 Nov 2025 03:13:04 -0800 Subject: [PATCH 2/4] Switch to portable attribute syntax --- .../clang/Basic/DiagnosticSemaKinds.td | 9 ++- clang/lib/Sema/SemaChecking.cpp | 28 ++++++--- clang/test/Sema/attr-format-missing-gnu.c | 20 ++++++ .../Sema/attr-format-missing-unsupported.c | 17 +++++ clang/test/Sema/attr-format-missing.c | 62 +++++++++---------- clang/test/Sema/attr-format-missing.cpp | 24 +++---- 6 files changed, 102 insertions(+), 58 deletions(-) create mode 100644 clang/test/Sema/attr-format-missing-gnu.c create mode 100644 clang/test/Sema/attr-format-missing-unsupported.c diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td index 78c5caf79eab7..37d7e9591d32b 100644 --- a/clang/include/clang/Basic/DiagnosticSemaKinds.td +++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td @@ -3478,11 +3478,10 @@ 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 " "string">; -def warn_missing_format_attribute - : Warning<"diagnostic behavior may be improved by adding the '%0' format " - "attribute to the declaration of %1">, - InGroup<DiagGroup<"missing-format-attribute">>, - DefaultIgnore; +def warn_missing_format_attribute : Warning< + "diagnostic behavior may be improved by adding the '%0' format " + "attribute to the declaration of %1">, + InGroup<DiagGroup<"missing-format-attribute">>, DefaultIgnore; def err_callback_attribute_no_callee : Error< "'callback' attribute specifies no callback callee">; def err_callback_attribute_invalid_callee : Error< diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp index 502e9fd099144..bb11b6077e03f 100644 --- a/clang/lib/Sema/SemaChecking.cpp +++ b/clang/lib/Sema/SemaChecking.cpp @@ -6636,11 +6636,10 @@ static StringLiteralCheckType checkFormatStringExpr( if (InitList->isStringLiteralInit()) Init = InitList->getInit(0)->IgnoreParenImpCasts(); } - return checkFormatStringExpr(S, ReferenceFormatString, Init, Args, - APK, format_idx, firstDataArg, Type, - CallType, - /*InFunctionCall*/ false, CheckedVarArgs, - UncoveredArg, Offset, CallerParamIdx); + return checkFormatStringExpr( + S, ReferenceFormatString, Init, Args, APK, format_idx, + firstDataArg, Type, CallType, /*InFunctionCall=*/false, + CheckedVarArgs, UncoveredArg, Offset, CallerParamIdx); } } @@ -7065,13 +7064,21 @@ static void CheckMissingFormatAttributes(Sema *S, FormatStringType FormatType, // Emit the diagnostic and fixit. unsigned FormatStringIndex = CallerParamIdx + CallerArgumentIndexOffset; StringRef FormatTypeName = S->GetFormatStringTypeName(FormatType); + StringRef AttrPrefix, AttrSuffix; + if (S->getLangOpts().C23 || S->getLangOpts().CPlusPlus11) { + AttrPrefix = "[[gnu::format("; + AttrSuffix = ")]] "; + } else { + AttrPrefix = "__attribute__((format("; + AttrSuffix = "))) "; + } S->Diag(Loc, diag::warn_missing_format_attribute) << FormatTypeName << Caller - << FixItHint::CreateInsertion(Caller->getFirstDecl()->getLocation(), - (llvm::Twine("__attribute__((format(") + - FormatTypeName + ", " + + << FixItHint::CreateInsertion(Caller->getFirstDecl()->getBeginLoc(), + (AttrPrefix + FormatTypeName + ", " + llvm::Twine(FormatStringIndex) + ", " + - llvm::Twine(FirstArgumentIndex) + ")))") + llvm::Twine(FirstArgumentIndex) + + AttrSuffix) .str()); S->Diag(Caller->getFirstDecl()->getLocation(), diag::note_callee_decl) << Caller; @@ -7133,7 +7140,8 @@ bool Sema::CheckFormatArguments(ArrayRef<const Expr *> Args, SourceMgr.isInSystemMacro(FormatLoc)) return false; - if (CallerParamIdx) + const LangOptions &LO = getLangOpts(); + if (CallerParamIdx && (LO.GNUMode || LO.C23 || LO.CPlusPlus11)) CheckMissingFormatAttributes(this, Type, format_idx, firstDataArg, Args, APK, *CallerParamIdx, Loc); diff --git a/clang/test/Sema/attr-format-missing-gnu.c b/clang/test/Sema/attr-format-missing-gnu.c new file mode 100644 index 0000000000000..4ba7d64107d3a --- /dev/null +++ b/clang/test/Sema/attr-format-missing-gnu.c @@ -0,0 +1,20 @@ +// RUN: %clang_cc1 -fsyntax-only -verify -std=gnu11 -Wmissing-format-attribute %s +// RUN: %clang_cc1 -fsyntax-only -verify -x c++ -std=gnu++98 -Wmissing-format-attribute %s +// RUN: %clang_cc1 -fsyntax-only -std=gnu11 -Wmissing-format-attribute -fdiagnostics-parseable-fixits %s 2>&1 | FileCheck %s +// RUN: %clang_cc1 -fsyntax-only -x c++ -std=gnu++98 -Wmissing-format-attribute -fdiagnostics-parseable-fixits %s 2>&1 | FileCheck %s + +typedef unsigned long size_t; +typedef long ssize_t; +typedef __builtin_va_list va_list; + +__attribute__((format(printf, 1, 0))) +int vprintf(const char *, va_list); + +// Test that attribute fixit is specified using the GNU extension format when -std=gnuXY or -std=gnu++XY. + +// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:1-[[@LINE+1]]:1}:"__attribute__((format(printf, 1, 0))) " +void f1(char *out, va_list args) // #f1 +{ + vprintf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'printf' format attribute to the declaration of 'f1'}} + // expected-note@#f1 {{'f1' declared here}} +} diff --git a/clang/test/Sema/attr-format-missing-unsupported.c b/clang/test/Sema/attr-format-missing-unsupported.c new file mode 100644 index 0000000000000..2694ce1b9bb49 --- /dev/null +++ b/clang/test/Sema/attr-format-missing-unsupported.c @@ -0,0 +1,17 @@ +// RUN: %clang_cc1 -fsyntax-only -verify -std=c11 -Wmissing-format-attribute %s +// RUN: %clang_cc1 -fsyntax-only -verify -x c++ -std=c++98 -Wmissing-format-attribute %s + +typedef unsigned long size_t; +typedef long ssize_t; +typedef __builtin_va_list va_list; + +__attribute__((format(printf, 1, 0))) +int vprintf(const char *, va_list); + +// Test that diagnostic is disabled when the standard doesn't support a portable attribute syntax. +// expected-no-diagnostics + +void f1(char *out, va_list args) // #f1 +{ + vprintf(out, args); +} diff --git a/clang/test/Sema/attr-format-missing.c b/clang/test/Sema/attr-format-missing.c index 7e5131153f661..071054dfa1e6d 100644 --- a/clang/test/Sema/attr-format-missing.c +++ b/clang/test/Sema/attr-format-missing.c @@ -1,47 +1,47 @@ -// RUN: %clang_cc1 -fsyntax-only -verify -Wmissing-format-attribute %s -// RUN: %clang_cc1 -fsyntax-only -Wmissing-format-attribute -fdiagnostics-parseable-fixits %s 2>&1 | FileCheck %s +// RUN: %clang_cc1 -fsyntax-only -verify -std=c23 -Wmissing-format-attribute %s +// RUN: %clang_cc1 -fsyntax-only -std=c23 -Wmissing-format-attribute -fdiagnostics-parseable-fixits %s 2>&1 | FileCheck %s typedef unsigned long size_t; typedef long ssize_t; typedef __builtin_va_list va_list; -__attribute__((format(printf, 1, 2))) +[[gnu::format(printf, 1, 2)]] int printf(const char *, ...); -__attribute__((format(scanf, 1, 2))) +[[gnu::format(scanf, 1, 2)]] int scanf(const char *, ...); -__attribute__((format(printf, 1, 0))) +[[gnu::format(printf, 1, 0)]] int vprintf(const char *, va_list); -__attribute__((format(scanf, 1, 0))) +[[gnu::format(scanf, 1, 0)]] int vscanf(const char *, va_list); -__attribute__((format(printf, 2, 0))) +[[gnu::format(printf, 2, 0)]] int vsprintf(char *, const char *, va_list); struct tm { unsigned i; }; -__attribute__((format(strftime, 3, 0))) +[[gnu::format(strftime, 3, 0)]] size_t strftime(char *, size_t, const char *, const struct tm *); -__attribute__((format(strfmon, 3, 4))) +[[gnu::format(strfmon, 3, 4)]] ssize_t strfmon(char *, size_t, const char *, ...); -// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:6-[[@LINE+1]]:6}:"__attribute__((format(printf, 1, 0)))" +// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:1-[[@LINE+1]]:1}:"{{\[\[}}gnu::format(printf, 1, 0)]] " void f1(char *out, va_list args) // #f1 { vprintf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'printf' format attribute to the declaration of 'f1'}} // expected-note@#f1 {{'f1' declared here}} } -// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:6-[[@LINE+1]]:6}:"__attribute__((format(scanf, 1, 0)))" +// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:1-[[@LINE+1]]:1}:"{{\[\[}}gnu::format(scanf, 1, 0)]] " void f2(const char *out, va_list args) // #f2 { vscanf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'scanf' format attribute to the declaration of 'f2'}} // expected-note@#f2 {{'f2' declared here}} } -// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:6-[[@LINE+1]]:6}:"__attribute__((format(printf, 1, 2)))" +// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:1-[[@LINE+1]]:1}:"{{\[\[}}gnu::format(printf, 1, 2)]] " void f3(const char *out, ... /* args */) // #f3 { va_list args; @@ -49,7 +49,7 @@ void f3(const char *out, ... /* args */) // #f3 // expected-note@#f3 {{'f3' declared here}} } -// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:6-[[@LINE+1]]:6}:"__attribute__((format(scanf, 1, 2)))" +// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:1-[[@LINE+1]]:1}:"{{\[\[}}gnu::format(scanf, 1, 2)]] " void f4(const char *out, ... /* args */) // #f4 { va_list args; @@ -57,8 +57,8 @@ void f4(const char *out, ... /* args */) // #f4 // expected-note@#f4 {{'f4' declared here}} } -// CHECK: fix-it:"{{.*}}":{[[@LINE+2]]:6-[[@LINE+2]]:6}:"__attribute__((format(printf, 2, 3)))" -__attribute__((format(printf, 1, 3))) +// CHECK: fix-it:"{{.*}}":{[[@LINE+2]]:1-[[@LINE+2]]:1}:"{{\[\[}}gnu::format(printf, 2, 3)]] " +[[gnu::format(printf, 1, 3)]] void f5(char *out, const char *format, ... /* args */) // #f5 { va_list args; @@ -66,7 +66,7 @@ void f5(char *out, const char *format, ... /* args */) // #f5 // expected-note@#f5 {{'f5' declared here}} } -__attribute__((format(scanf, 1, 3))) +[[gnu::format(scanf, 1, 3)]] void f6(char *out, const char *format, ... /* args */) // #f6 { va_list args; @@ -100,8 +100,8 @@ void f9(va_list args) vscanf("test", args); } -// CHECK: fix-it:"{{.*}}":{[[@LINE+2]]:6-[[@LINE+2]]:6}:"__attribute__((format(scanf, 1, 2)))" -// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:6-[[@LINE+1]]:6}:"__attribute__((format(printf, 1, 2)))" +// CHECK: fix-it:"{{.*}}":{[[@LINE+2]]:1-[[@LINE+2]]:1}:"{{\[\[}}gnu::format(scanf, 1, 2)]] " +// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:1-[[@LINE+1]]:1}:"{{\[\[}}gnu::format(printf, 1, 2)]] " void f10(const char *out, ... /* args */) // #f10 { va_list args; @@ -111,7 +111,7 @@ void f10(const char *out, ... /* args */) // #f10 // expected-note@#f10 {{'f10' declared here}} } -// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:6-[[@LINE+1]]:6}:"__attribute__((format(printf, 1, 2)))" +// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:1-[[@LINE+1]]:1}:"{{\[\[}}gnu::format(printf, 1, 2)]] " void f11(const char out[], ... /* args */) // #f11 { va_list args; @@ -121,7 +121,7 @@ void f11(const char out[], ... /* args */) // #f11 // expected-note@#f11 {{'f11' declared here}} } -// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:6-[[@LINE+1]]:6}:"__attribute__((format(printf, 1, 0)))" +// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:1-[[@LINE+1]]:1}:"{{\[\[}}gnu::format(printf, 1, 0)]] " void f12(char* out) // #f12 { va_list args; @@ -131,8 +131,8 @@ void f12(char* out) // #f12 // expected-note@#f12 {{'f12' declared here}} } -// CHECK: fix-it:"{{.*}}":{[[@LINE+2]]:6-[[@LINE+2]]:6}:"__attribute__((format(scanf, 1, 2)))" -// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:6-[[@LINE+1]]:6}:"__attribute__((format(printf, 1, 2)))" +// CHECK: fix-it:"{{.*}}":{[[@LINE+2]]:1-[[@LINE+2]]:1}:"{{\[\[}}gnu::format(scanf, 1, 2)]] " +// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:1-[[@LINE+1]]:1}:"{{\[\[}}gnu::format(printf, 1, 2)]] " void f13(char *out, ... /* args */) // #f13 { va_list args; @@ -142,8 +142,8 @@ void f13(char *out, ... /* args */) // #f13 // expected-note@#f13 {{'f13' declared here}} } -// CHECK: fix-it:"{{.*}}":{[[@LINE+2]]:6-[[@LINE+2]]:6}:"__attribute__((format(scanf, 1, 0)))" -// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:6-[[@LINE+1]]:6}:"__attribute__((format(printf, 1, 0)))" +// CHECK: fix-it:"{{.*}}":{[[@LINE+2]]:1-[[@LINE+2]]:1}:"{{\[\[}}gnu::format(scanf, 1, 0)]] " +// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:1-[[@LINE+1]]:1}:"{{\[\[}}gnu::format(printf, 1, 0)]] " void f14(char *out, va_list args) // #f14 { vscanf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'scanf' format attribute to the declaration of 'f14'}} @@ -152,7 +152,7 @@ void f14(char *out, va_list args) // #f14 // expected-note@#f14 {{'f14' declared here}} } -// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:6-[[@LINE+1]]:6}:"__attribute__((format(scanf, 1, 2)))" +// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:1-[[@LINE+1]]:1}:"{{\[\[}}gnu::format(scanf, 1, 2)]] " void f15(char *out, ... /* args */) // #f15 { va_list args; @@ -162,8 +162,8 @@ void f15(char *out, ... /* args */) // #f15 // expected-note@#f15 {{'f15' declared here}} } -// CHECK: fix-it:"{{.*}}":{[[@LINE+2]]:6-[[@LINE+2]]:6}:"__attribute__((format(printf, 1, 3)))" -// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:6-[[@LINE+1]]:6}:"__attribute__((format(printf, 2, 3)))" +// CHECK: fix-it:"{{.*}}":{[[@LINE+2]]:1-[[@LINE+2]]:1}:"{{\[\[}}gnu::format(printf, 1, 3)]] " +// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:1-[[@LINE+1]]:1}:"{{\[\[}}gnu::format(printf, 2, 3)]] " void f16(char *ch, const char *out, ... /* args */) // #f16 { va_list args; @@ -173,7 +173,7 @@ void f16(char *ch, const char *out, ... /* args */) // #f16 // expected-note@#f16 {{'f16' declared here}} } -// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:6-[[@LINE+1]]:6}:"__attribute__((format(printf, 1, 2)))" +// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:1-[[@LINE+1]]:1}:"{{\[\[}}gnu::format(printf, 1, 2)]] " void f17(const char *a, ...) // #f17 { va_list ap; @@ -182,7 +182,7 @@ void f17(const char *a, ...) // #f17 // expected-note@#f17 {{'f17' declared here}} } -// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:6-[[@LINE+1]]:6}:"__attribute__((format(printf, 1, 2)))" +// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:1-[[@LINE+1]]:1}:"{{\[\[}}gnu::format(printf, 1, 2)]] " void f18(char *fmt, unsigned x, unsigned y, unsigned z) // #f18 { printf(fmt, x, y, z); // expected-warning {{diagnostic behavior may be improved by adding the 'printf' format attribute to the declaration of 'f18'}} @@ -200,7 +200,7 @@ void f20(char *out, ... /* args */) printf(out, 1); // No warning, arguments are not passed to printf. } -// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:6-[[@LINE+1]]:6}:"__attribute__((format(strftime, 3, 0)))" +// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:1-[[@LINE+1]]:1}:"{{\[\[}}gnu::format(strftime, 3, 0)]] " void f21(char *out, const size_t len, const char *format) // #f21 { struct tm tm_arg; @@ -209,7 +209,7 @@ void f21(char *out, const size_t len, const char *format) // #f21 // expected-note@#f21 {{'f21' declared here}} } -// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:6-[[@LINE+1]]:6}:"__attribute__((format(strfmon, 3, 4)))" +// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:1-[[@LINE+1]]:1}:"{{\[\[}}gnu::format(strfmon, 3, 4)]] " void f22(char *out, const size_t len, const char *format, int x, int y) // #f22 { strfmon(out, len, format, x, y); // expected-warning {{diagnostic behavior may be improved by adding the 'strfmon' format attribute to the declaration of 'f22'}} diff --git a/clang/test/Sema/attr-format-missing.cpp b/clang/test/Sema/attr-format-missing.cpp index 90d667531ce0a..23f643bb80058 100644 --- a/clang/test/Sema/attr-format-missing.cpp +++ b/clang/test/Sema/attr-format-missing.cpp @@ -4,27 +4,27 @@ typedef __SIZE_TYPE__ size_t; typedef __builtin_va_list va_list; -__attribute__((__format__(__printf__, 1, 2))) +[[gnu::format(printf, 1, 2)]] int printf(const char *, ...); -__attribute__((__format__(__scanf__, 1, 2))) +[[gnu::format(scanf, 1, 2)]] int scanf(const char *, ...); -__attribute__((__format__(__printf__, 1, 0))) +[[gnu::format(printf, 1, 0)]] int vprintf(const char *, va_list); -__attribute__((__format__(__scanf__, 1, 0))) +[[gnu::format(scanf, 1, 0)]] int vscanf(const char *, va_list); -__attribute__((__format__(__printf__, 2, 0))) +[[gnu::format(printf, 2, 0)]] int vsprintf(char *, const char *, va_list); -__attribute__((__format__(__printf__, 3, 0))) +[[gnu::format(printf, 3, 0)]] int vsnprintf(char *, size_t, const char *, va_list); struct S1 { - // CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:8-[[@LINE+1]]:8}:"__attribute__((format(scanf, 2, 3)))" + // CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:3-[[@LINE+1]]:3}:"{{\[\[}}gnu::format(scanf, 2, 3)]] " void fn1(const char *out, ... /* args */) // #S1_fn1 { va_list args; @@ -32,10 +32,10 @@ struct S1 // expected-note@#S1_fn1 {{'fn1' declared here}} } - __attribute__((format(printf, 2, 0))) + [[gnu::format(printf, 2, 0)]] void print(const char *out, va_list args); - // CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:8-[[@LINE+1]]:8}:"__attribute__((format(printf, 2, 3)))" + // CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:3-[[@LINE+1]]:3}:"{{\[\[}}gnu::format(printf, 2, 3)]] " void fn2(const char *out, ... /* args */) // #S1_fn2 { va_list args; @@ -43,14 +43,14 @@ struct S1 // expected-note@#S1_fn2 {{'fn2' declared here}} } - // CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:8-[[@LINE+1]]:8}:"__attribute__((format(printf, 2, 0)))" + // CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:3-[[@LINE+1]]:3}:"{{\[\[}}gnu::format(printf, 2, 0)]] " void fn3(const char *out, va_list args) // #S1_fn3 { print(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'printf' format attribute to the declaration of 'fn3'}} // expected-note@#S1_fn3 {{'fn3' declared here}} } - // CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:8-[[@LINE+1]]:8}:"__attribute__((format(printf, 2, 3)))" + // CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:3-[[@LINE+1]]:3}:"{{\[\[}}gnu::format(printf, 2, 3)]] " void fn4(this S1& self, const char *out, ... /* args */) // #S1_fn4 { va_list args; @@ -58,7 +58,7 @@ struct S1 // expected-note@#S1_fn4 {{'fn4' declared here}} } - // CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:8-[[@LINE+1]]:8}:"__attribute__((format(printf, 2, 0)))" + // CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:3-[[@LINE+1]]:3}:"{{\[\[}}gnu::format(printf, 2, 0)]] " void fn5(this S1& self, const char *out, va_list args) // #S1_fn5 { self.print(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'printf' format attribute to the declaration of 'fn5'}} >From a0a4ca6383a88215b8edc9d2814ee0694a28f406 Mon Sep 17 00:00:00 2001 From: Vladimir Vuksanovic <[email protected]> Date: Mon, 17 Nov 2025 00:52:50 -0800 Subject: [PATCH 3/4] Address review comments - Check now works or Objective-C - Add attribute arguments to diagnostic message - Rename CallerParamIdx to CallerFormatParamIdx - Fix typo --- .../clang/Basic/DiagnosticSemaKinds.td | 4 +- clang/lib/Sema/SemaChecking.cpp | 118 +++++++++--------- clang/test/Sema/attr-format-missing-gnu.c | 2 +- clang/test/Sema/attr-format-missing.c | 57 ++++----- clang/test/Sema/attr-format-missing.cpp | 10 +- clang/test/Sema/attr-format-missing.m | 31 +++++ 6 files changed, 130 insertions(+), 92 deletions(-) create mode 100644 clang/test/Sema/attr-format-missing.m diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td index 37d7e9591d32b..c42ee4ddb4e65 100644 --- a/clang/include/clang/Basic/DiagnosticSemaKinds.td +++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td @@ -3479,8 +3479,8 @@ def err_format_attribute_implicit_this_format_string : Error< "format attribute cannot specify the implicit this argument as the format " "string">; def warn_missing_format_attribute : Warning< - "diagnostic behavior may be improved by adding the '%0' format " - "attribute to the declaration of %1">, + "diagnostic behavior may be improved by adding the '%0' attribute to the " + "declaration of %1">, InGroup<DiagGroup<"missing-format-attribute">>, DefaultIgnore; def err_callback_attribute_no_callee : Error< "'callback' attribute specifies no callback callee">; diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp index bb11b6077e03f..b78aec68bec62 100644 --- a/clang/lib/Sema/SemaChecking.cpp +++ b/clang/lib/Sema/SemaChecking.cpp @@ -17,6 +17,7 @@ #include "clang/AST/ASTDiagnostic.h" #include "clang/AST/Attr.h" #include "clang/AST/AttrIterator.h" +#include "clang/AST/Attrs.inc" #include "clang/AST/CharUnits.h" #include "clang/AST/Decl.h" #include "clang/AST/DeclBase.h" @@ -6511,14 +6512,16 @@ static const Expr *maybeConstEvalStringLiteral(ASTContext &Context, // If this function returns false on the arguments to a function expecting a // format string, we will usually need to emit a warning. // True string literals are then checked by CheckFormatString. -static StringLiteralCheckType checkFormatStringExpr( - Sema &S, const StringLiteral *ReferenceFormatString, const Expr *E, - ArrayRef<const Expr *> Args, Sema::FormatArgumentPassingKind APK, - unsigned format_idx, unsigned firstDataArg, FormatStringType Type, - VariadicCallType CallType, bool InFunctionCall, - llvm::SmallBitVector &CheckedVarArgs, UncoveredArgHandler &UncoveredArg, - llvm::APSInt Offset, std::optional<unsigned> *CallerParamIdx = nullptr, - bool IgnoreStringsWithoutSpecifiers = false) { +static StringLiteralCheckType +checkFormatStringExpr(Sema &S, const StringLiteral *ReferenceFormatString, + const Expr *E, ArrayRef<const Expr *> Args, + Sema::FormatArgumentPassingKind APK, unsigned format_idx, + unsigned firstDataArg, FormatStringType Type, + VariadicCallType CallType, bool InFunctionCall, + llvm::SmallBitVector &CheckedVarArgs, + UncoveredArgHandler &UncoveredArg, llvm::APSInt Offset, + std::optional<unsigned> *CallerFormatParamIdx = nullptr, + bool IgnoreStringsWithoutSpecifiers = false) { if (S.isConstantEvaluatedContext()) return SLCT_NotALiteral; tryAgain: @@ -6540,10 +6543,11 @@ static StringLiteralCheckType checkFormatStringExpr( case Stmt::InitListExprClass: // Handle expressions like {"foobar"}. if (const clang::Expr *SLE = maybeConstEvalStringLiteral(S.Context, E)) { - return checkFormatStringExpr( - S, ReferenceFormatString, SLE, Args, APK, format_idx, firstDataArg, - Type, CallType, /*InFunctionCall*/ false, CheckedVarArgs, - UncoveredArg, Offset, CallerParamIdx, IgnoreStringsWithoutSpecifiers); + return checkFormatStringExpr(S, ReferenceFormatString, SLE, Args, APK, + format_idx, firstDataArg, Type, CallType, + /*InFunctionCall*/ false, CheckedVarArgs, + UncoveredArg, Offset, CallerFormatParamIdx, + IgnoreStringsWithoutSpecifiers); } return SLCT_NotALiteral; case Stmt::BinaryConditionalOperatorClass: @@ -6575,10 +6579,11 @@ static StringLiteralCheckType checkFormatStringExpr( if (!CheckLeft) Left = SLCT_UncheckedLiteral; else { - Left = checkFormatStringExpr( - S, ReferenceFormatString, C->getTrueExpr(), Args, APK, format_idx, - firstDataArg, Type, CallType, InFunctionCall, CheckedVarArgs, - UncoveredArg, Offset, CallerParamIdx, IgnoreStringsWithoutSpecifiers); + Left = checkFormatStringExpr(S, ReferenceFormatString, C->getTrueExpr(), + Args, APK, format_idx, firstDataArg, Type, + CallType, InFunctionCall, CheckedVarArgs, + UncoveredArg, Offset, CallerFormatParamIdx, + IgnoreStringsWithoutSpecifiers); if (Left == SLCT_NotALiteral || !CheckRight) { return Left; } @@ -6587,7 +6592,8 @@ static StringLiteralCheckType checkFormatStringExpr( StringLiteralCheckType Right = checkFormatStringExpr( S, ReferenceFormatString, C->getFalseExpr(), Args, APK, format_idx, firstDataArg, Type, CallType, InFunctionCall, CheckedVarArgs, - UncoveredArg, Offset, CallerParamIdx, IgnoreStringsWithoutSpecifiers); + UncoveredArg, Offset, CallerFormatParamIdx, + IgnoreStringsWithoutSpecifiers); return (CheckLeft && Left < Right) ? Left : Right; } @@ -6639,7 +6645,7 @@ static StringLiteralCheckType checkFormatStringExpr( return checkFormatStringExpr( S, ReferenceFormatString, Init, Args, APK, format_idx, firstDataArg, Type, CallType, /*InFunctionCall=*/false, - CheckedVarArgs, UncoveredArg, Offset, CallerParamIdx); + CheckedVarArgs, UncoveredArg, Offset, CallerFormatParamIdx); } } @@ -6691,8 +6697,8 @@ static StringLiteralCheckType checkFormatStringExpr( // format arguments, in all cases. // if (const auto *PV = dyn_cast<ParmVarDecl>(VD)) { - if (CallerParamIdx) - *CallerParamIdx = PV->getFunctionScopeIndex(); + if (CallerFormatParamIdx) + *CallerFormatParamIdx = PV->getFunctionScopeIndex(); if (const auto *D = dyn_cast<Decl>(PV->getDeclContext())) { for (const auto *PVFormatMatches : D->specific_attrs<FormatMatchesAttr>()) { @@ -6718,7 +6724,7 @@ static StringLiteralCheckType checkFormatStringExpr( S, ReferenceFormatString, PVFormatMatches->getFormatString(), Args, APK, format_idx, firstDataArg, Type, CallType, /*InFunctionCall*/ false, CheckedVarArgs, UncoveredArg, - Offset, CallerParamIdx, IgnoreStringsWithoutSpecifiers); + Offset, CallerFormatParamIdx, IgnoreStringsWithoutSpecifiers); } } @@ -6773,7 +6779,7 @@ static StringLiteralCheckType checkFormatStringExpr( StringLiteralCheckType Result = checkFormatStringExpr( S, ReferenceFormatString, Arg, Args, APK, format_idx, firstDataArg, Type, CallType, InFunctionCall, CheckedVarArgs, UncoveredArg, - Offset, CallerParamIdx, IgnoreStringsWithoutSpecifiers); + Offset, CallerFormatParamIdx, IgnoreStringsWithoutSpecifiers); if (IsFirst) { CommonResult = Result; IsFirst = false; @@ -6787,19 +6793,20 @@ static StringLiteralCheckType checkFormatStringExpr( if (BuiltinID == Builtin::BI__builtin___CFStringMakeConstantString || BuiltinID == Builtin::BI__builtin___NSStringMakeConstantString) { const Expr *Arg = CE->getArg(0); - return checkFormatStringExpr(S, ReferenceFormatString, Arg, Args, APK, - format_idx, firstDataArg, Type, CallType, - InFunctionCall, CheckedVarArgs, - UncoveredArg, Offset, CallerParamIdx, - IgnoreStringsWithoutSpecifiers); + return checkFormatStringExpr( + S, ReferenceFormatString, Arg, Args, APK, format_idx, + firstDataArg, Type, CallType, InFunctionCall, CheckedVarArgs, + UncoveredArg, Offset, CallerFormatParamIdx, + IgnoreStringsWithoutSpecifiers); } } } if (const Expr *SLE = maybeConstEvalStringLiteral(S.Context, E)) - return checkFormatStringExpr( - S, ReferenceFormatString, SLE, Args, APK, format_idx, firstDataArg, - Type, CallType, /*InFunctionCall*/ false, CheckedVarArgs, - UncoveredArg, Offset, CallerParamIdx, IgnoreStringsWithoutSpecifiers); + return checkFormatStringExpr(S, ReferenceFormatString, SLE, Args, APK, + format_idx, firstDataArg, Type, CallType, + /*InFunctionCall*/ false, CheckedVarArgs, + UncoveredArg, Offset, CallerFormatParamIdx, + IgnoreStringsWithoutSpecifiers); return SLCT_NotALiteral; } case Stmt::ObjCMessageExprClass: { @@ -6825,7 +6832,7 @@ static StringLiteralCheckType checkFormatStringExpr( return checkFormatStringExpr( S, ReferenceFormatString, Arg, Args, APK, format_idx, firstDataArg, Type, CallType, InFunctionCall, CheckedVarArgs, UncoveredArg, - Offset, CallerParamIdx, IgnoreStringsWithoutSpecifiers); + Offset, CallerFormatParamIdx, IgnoreStringsWithoutSpecifiers); } } @@ -7011,10 +7018,12 @@ static void CheckMissingFormatAttributes(Sema *S, FormatStringType FormatType, Sema::FormatArgumentPassingKind APK, unsigned CallerParamIdx, SourceLocation Loc) { - const FunctionDecl *Caller = S->getCurFunctionDecl(); + NamedDecl *Caller = S->getCurFunctionOrMethodDecl(); if (!Caller) return; + unsigned NumCallerParams = getFunctionOrMethodNumParams(Caller); + // Find the offset to convert between attribute and parameter indexes. unsigned CallerArgumentIndexOffset = hasImplicitObjectParameter(Caller) ? 2 : 1; @@ -7030,12 +7039,11 @@ static void CheckMissingFormatAttributes(Sema *S, FormatStringType FormatType, // emit a diag with the caller idx, otherwise we can't determine the callee // arguments. unsigned NumCalleeArgs = Args.size() - FirstArg; - if (NumCalleeArgs == 0 || Caller->getNumParams() < NumCalleeArgs) { - // There aren't enough arugments in the caller to pass to callee. + if (NumCalleeArgs == 0 || NumCallerParams < NumCalleeArgs) { + // There aren't enough arguments in the caller to pass to callee. return; } - for (unsigned CalleeIdx = Args.size() - 1, - CallerIdx = Caller->getNumParams() - 1; + for (unsigned CalleeIdx = Args.size() - 1, CallerIdx = NumCallerParams - 1; CalleeIdx >= FirstArg; --CalleeIdx, --CallerIdx) { const auto *Arg = dyn_cast<DeclRefExpr>(Args[CalleeIdx]->IgnoreParenCasts()); @@ -7046,15 +7054,14 @@ static void CheckMissingFormatAttributes(Sema *S, FormatStringType FormatType, return; } FirstArgumentIndex = - Caller->getNumParams() + CallerArgumentIndexOffset - NumCalleeArgs; + NumCallerParams + CallerArgumentIndexOffset - NumCalleeArgs; break; } case Sema::FormatArgumentPassingKind::FAPK_VAList: // Caller arguments are either variadic or a va_list. - FirstArgumentIndex = - Caller->isVariadic() - ? (Caller->getNumParams() + CallerArgumentIndexOffset) - : 0; + FirstArgumentIndex = isFunctionOrMethodVariadic(Caller) + ? (NumCallerParams + CallerArgumentIndexOffset) + : 0; break; case Sema::FormatArgumentPassingKind::FAPK_Elsewhere: // Args are not passed to the callee. @@ -7063,25 +7070,24 @@ static void CheckMissingFormatAttributes(Sema *S, FormatStringType FormatType, // Emit the diagnostic and fixit. unsigned FormatStringIndex = CallerParamIdx + CallerArgumentIndexOffset; - StringRef FormatTypeName = S->GetFormatStringTypeName(FormatType); StringRef AttrPrefix, AttrSuffix; if (S->getLangOpts().C23 || S->getLangOpts().CPlusPlus11) { - AttrPrefix = "[[gnu::format("; - AttrSuffix = ")]] "; + AttrPrefix = "[[gnu::"; + AttrSuffix = "]] "; } else { - AttrPrefix = "__attribute__((format("; - AttrSuffix = "))) "; + AttrPrefix = "__attribute__(("; + AttrSuffix = ")) "; } + StringRef FormatTypeName = S->GetFormatStringTypeName(FormatType); + std::string Attr = + ("format(" + FormatTypeName + ", " + llvm::Twine(FormatStringIndex) + + ", " + llvm::Twine(FirstArgumentIndex) + ")") + .str(); S->Diag(Loc, diag::warn_missing_format_attribute) - << FormatTypeName << Caller - << FixItHint::CreateInsertion(Caller->getFirstDecl()->getBeginLoc(), - (AttrPrefix + FormatTypeName + ", " + - llvm::Twine(FormatStringIndex) + ", " + - llvm::Twine(FirstArgumentIndex) + - AttrSuffix) - .str()); - S->Diag(Caller->getFirstDecl()->getLocation(), diag::note_callee_decl) - << Caller; + << Attr << Caller + << FixItHint::CreateInsertion(Caller->getBeginLoc(), + (AttrPrefix + Attr + AttrSuffix).str()); + S->Diag(Caller->getLocation(), diag::note_entity_declared_at) << Caller; } bool Sema::CheckFormatArguments(ArrayRef<const Expr *> Args, diff --git a/clang/test/Sema/attr-format-missing-gnu.c b/clang/test/Sema/attr-format-missing-gnu.c index 4ba7d64107d3a..83f20b8b85a7b 100644 --- a/clang/test/Sema/attr-format-missing-gnu.c +++ b/clang/test/Sema/attr-format-missing-gnu.c @@ -15,6 +15,6 @@ int vprintf(const char *, va_list); // CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:1-[[@LINE+1]]:1}:"__attribute__((format(printf, 1, 0))) " void f1(char *out, va_list args) // #f1 { - vprintf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'printf' format attribute to the declaration of 'f1'}} + vprintf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'format(printf, 1, 0)' attribute to the declaration of 'f1'}} // expected-note@#f1 {{'f1' declared here}} } diff --git a/clang/test/Sema/attr-format-missing.c b/clang/test/Sema/attr-format-missing.c index 071054dfa1e6d..5d4eeac18773b 100644 --- a/clang/test/Sema/attr-format-missing.c +++ b/clang/test/Sema/attr-format-missing.c @@ -28,33 +28,33 @@ size_t strftime(char *, size_t, const char *, const struct tm *); ssize_t strfmon(char *, size_t, const char *, ...); // CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:1-[[@LINE+1]]:1}:"{{\[\[}}gnu::format(printf, 1, 0)]] " -void f1(char *out, va_list args) // #f1 +void f1(const char *fmt, va_list args) // #f1 { - vprintf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'printf' format attribute to the declaration of 'f1'}} + vprintf(fmt, args); // expected-warning {{diagnostic behavior may be improved by adding the 'format(printf, 1, 0)' attribute to the declaration of 'f1'}} // expected-note@#f1 {{'f1' declared here}} } // CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:1-[[@LINE+1]]:1}:"{{\[\[}}gnu::format(scanf, 1, 0)]] " -void f2(const char *out, va_list args) // #f2 +void f2(const char *fmt, va_list args) // #f2 { - vscanf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'scanf' format attribute to the declaration of 'f2'}} - // expected-note@#f2 {{'f2' declared here}} + vscanf(fmt, args); // expected-warning {{diagnostic behavior may be improved by adding the 'format(scanf, 1, 0)' attribute to the declaration of 'f2'}} + // expected-note@#f2 {{'f2' declared here}} } // CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:1-[[@LINE+1]]:1}:"{{\[\[}}gnu::format(printf, 1, 2)]] " -void f3(const char *out, ... /* args */) // #f3 +void f3(const char *fmt, ... /* args */) // #f3 { va_list args; - vprintf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'printf' format attribute to the declaration of 'f3'}} + vprintf(fmt, args); // expected-warning {{diagnostic behavior may be improved by adding the 'format(printf, 1, 2)' attribute to the declaration of 'f3'}} // expected-note@#f3 {{'f3' declared here}} } // CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:1-[[@LINE+1]]:1}:"{{\[\[}}gnu::format(scanf, 1, 2)]] " -void f4(const char *out, ... /* args */) // #f4 +void f4(const char *fmt, ... /* args */) // #f4 { va_list args; - vscanf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'scanf' format attribute to the declaration of 'f4'}} - // expected-note@#f4 {{'f4' declared here}} + vscanf(fmt, args); // expected-warning {{diagnostic behavior may be improved by adding the 'format(scanf, 1, 2)' attribute to the declaration of 'f4'}} + // expected-note@#f4 {{'f4' declared here}} } // CHECK: fix-it:"{{.*}}":{[[@LINE+2]]:1-[[@LINE+2]]:1}:"{{\[\[}}gnu::format(printf, 2, 3)]] " @@ -62,15 +62,16 @@ void f4(const char *out, ... /* args */) // #f4 void f5(char *out, const char *format, ... /* args */) // #f5 { va_list args; - vsprintf(out, format, args); // expected-warning {{diagnostic behavior may be improved by adding the 'printf' format attribute to the declaration of 'f5'}} + vsprintf(out, format, args); // expected-warning {{diagnostic behavior may be improved by adding the 'format(printf, 2, 3)' attribute to the declaration of 'f5'}} // expected-note@#f5 {{'f5' declared here}} } +// CHECK: fix-it:"{{.*}}":{[[@LINE+2]]:1-[[@LINE+2]]:1}:"{{\[\[}}gnu::format(printf, 2, 3)]] " [[gnu::format(scanf, 1, 3)]] void f6(char *out, const char *format, ... /* args */) // #f6 { va_list args; - vsprintf(out, format, args); // expected-warning {{diagnostic behavior may be improved by adding the 'printf' format attribute to the declaration of 'f6'}} + vsprintf(out, format, args); // expected-warning {{diagnostic behavior may be improved by adding the 'format(printf, 2, 3)' attribute to the declaration of 'f6'}} // expected-note@#f6 {{'f6' declared here}} } @@ -105,9 +106,9 @@ void f9(va_list args) void f10(const char *out, ... /* args */) // #f10 { va_list args; - vscanf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'scanf' format attribute to the declaration of 'f10'}} + vscanf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'format(scanf, 1, 2)' attribute to the declaration of 'f10'}} // expected-note@#f10 {{'f10' declared here}} - vprintf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'printf' format attribute to the declaration of 'f10'}} + vprintf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'format(printf, 1, 2)' attribute to the declaration of 'f10'}} // expected-note@#f10 {{'f10' declared here}} } @@ -117,7 +118,7 @@ void f11(const char out[], ... /* args */) // #f11 va_list args; char ch[10] = "format"; vprintf(ch, args); - vsprintf(ch, out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'printf' format attribute to the declaration of 'f11'}} + vsprintf(ch, out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'format(printf, 1, 2)' attribute to the declaration of 'f11'}} // expected-note@#f11 {{'f11' declared here}} } @@ -127,7 +128,7 @@ void f12(char* out) // #f12 va_list args; const char *ch = "format"; vsprintf(out, ch, args); - vprintf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'printf' format attribute to the declaration of 'f12'}} + vprintf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'format(printf, 1, 0)' attribute to the declaration of 'f12'}} // expected-note@#f12 {{'f12' declared here}} } @@ -136,9 +137,9 @@ void f12(char* out) // #f12 void f13(char *out, ... /* args */) // #f13 { va_list args; - vscanf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'scanf' format attribute to the declaration of 'f13'}} + vscanf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'format(scanf, 1, 2)' attribute to the declaration of 'f13'}} // expected-note@#f13 {{'f13' declared here}} - vprintf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'printf' format attribute to the declaration of 'f13'}} + vprintf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'format(printf, 1, 2)' attribute to the declaration of 'f13'}} // expected-note@#f13 {{'f13' declared here}} } @@ -146,9 +147,9 @@ void f13(char *out, ... /* args */) // #f13 // CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:1-[[@LINE+1]]:1}:"{{\[\[}}gnu::format(printf, 1, 0)]] " void f14(char *out, va_list args) // #f14 { - vscanf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'scanf' format attribute to the declaration of 'f14'}} + vscanf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'format(scanf, 1, 0)' attribute to the declaration of 'f14'}} // expected-note@#f14 {{'f14' declared here}} - vprintf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'printf' format attribute to the declaration of 'f14'}} + vprintf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'format(printf, 1, 0)' attribute to the declaration of 'f14'}} // expected-note@#f14 {{'f14' declared here}} } @@ -156,9 +157,9 @@ void f14(char *out, va_list args) // #f14 void f15(char *out, ... /* args */) // #f15 { va_list args; - vscanf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'scanf' format attribute to the declaration of 'f15'}} + vscanf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'format(scanf, 1, 2)' attribute to the declaration of 'f15'}} // expected-note@#f15 {{'f15' declared here}} - vscanf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'scanf' format attribute to the declaration of 'f15'}} + vscanf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'format(scanf, 1, 2)' attribute to the declaration of 'f15'}} // expected-note@#f15 {{'f15' declared here}} } @@ -167,9 +168,9 @@ void f15(char *out, ... /* args */) // #f15 void f16(char *ch, const char *out, ... /* args */) // #f16 { va_list args; - vprintf(ch, args); // expected-warning {{diagnostic behavior may be improved by adding the 'printf' format attribute to the declaration of 'f16'}} + vprintf(ch, args); // expected-warning {{diagnostic behavior may be improved by adding the 'format(printf, 1, 3)' attribute to the declaration of 'f16'}} // expected-note@#f16 {{'f16' declared here}} - vprintf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'printf' format attribute to the declaration of 'f16'}} + vprintf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'format(printf, 2, 3)' attribute to the declaration of 'f16'}} // expected-note@#f16 {{'f16' declared here}} } @@ -178,14 +179,14 @@ void f17(const char *a, ...) // #f17 { va_list ap; const char *const b = a; - vprintf(b, ap); // expected-warning {{diagnostic behavior may be improved by adding the 'printf' format attribute to the declaration of 'f17'}} + vprintf(b, ap); // expected-warning {{diagnostic behavior may be improved by adding the 'format(printf, 1, 2)' attribute to the declaration of 'f17'}} // expected-note@#f17 {{'f17' declared here}} } // CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:1-[[@LINE+1]]:1}:"{{\[\[}}gnu::format(printf, 1, 2)]] " void f18(char *fmt, unsigned x, unsigned y, unsigned z) // #f18 { - printf(fmt, x, y, z); // expected-warning {{diagnostic behavior may be improved by adding the 'printf' format attribute to the declaration of 'f18'}} + printf(fmt, x, y, z); // expected-warning {{diagnostic behavior may be improved by adding the 'format(printf, 1, 2)' attribute to the declaration of 'f18'}} // expected-note@#f18 {{'f18' declared here}} } @@ -205,13 +206,13 @@ void f21(char *out, const size_t len, const char *format) // #f21 { struct tm tm_arg; tm_arg.i = 0; - strftime(out, len, format, &tm_arg); // expected-warning {{diagnostic behavior may be improved by adding the 'strftime' format attribute to the declaration of 'f21'}} + strftime(out, len, format, &tm_arg); // expected-warning {{diagnostic behavior may be improved by adding the 'format(strftime, 3, 0)' attribute to the declaration of 'f21'}} // expected-note@#f21 {{'f21' declared here}} } // CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:1-[[@LINE+1]]:1}:"{{\[\[}}gnu::format(strfmon, 3, 4)]] " void f22(char *out, const size_t len, const char *format, int x, int y) // #f22 { - strfmon(out, len, format, x, y); // expected-warning {{diagnostic behavior may be improved by adding the 'strfmon' format attribute to the declaration of 'f22'}} + strfmon(out, len, format, x, y); // expected-warning {{diagnostic behavior may be improved by adding the 'format(strfmon, 3, 4)' attribute to the declaration of 'f22'}} // expected-note@#f22 {{'f22' declared here}} } diff --git a/clang/test/Sema/attr-format-missing.cpp b/clang/test/Sema/attr-format-missing.cpp index 23f643bb80058..06b5ad1a68f3c 100644 --- a/clang/test/Sema/attr-format-missing.cpp +++ b/clang/test/Sema/attr-format-missing.cpp @@ -28,7 +28,7 @@ struct S1 void fn1(const char *out, ... /* args */) // #S1_fn1 { va_list args; - vscanf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'scanf' format attribute to the declaration of 'fn1'}} + vscanf(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'format(scanf, 2, 3)' attribute to the declaration of 'fn1'}} // expected-note@#S1_fn1 {{'fn1' declared here}} } @@ -39,14 +39,14 @@ struct S1 void fn2(const char *out, ... /* args */) // #S1_fn2 { va_list args; - print(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'printf' format attribute to the declaration of 'fn2'}} + print(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'format(printf, 2, 3)' attribute to the declaration of 'fn2'}} // expected-note@#S1_fn2 {{'fn2' declared here}} } // CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:3-[[@LINE+1]]:3}:"{{\[\[}}gnu::format(printf, 2, 0)]] " void fn3(const char *out, va_list args) // #S1_fn3 { - print(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'printf' format attribute to the declaration of 'fn3'}} + print(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'format(printf, 2, 0)' attribute to the declaration of 'fn3'}} // expected-note@#S1_fn3 {{'fn3' declared here}} } @@ -54,14 +54,14 @@ struct S1 void fn4(this S1& self, const char *out, ... /* args */) // #S1_fn4 { va_list args; - self.print(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'printf' format attribute to the declaration of 'fn4'}} + self.print(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'format(printf, 2, 3)' attribute to the declaration of 'fn4'}} // expected-note@#S1_fn4 {{'fn4' declared here}} } // CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:3-[[@LINE+1]]:3}:"{{\[\[}}gnu::format(printf, 2, 0)]] " void fn5(this S1& self, const char *out, va_list args) // #S1_fn5 { - self.print(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'printf' format attribute to the declaration of 'fn5'}} + self.print(out, args); // expected-warning {{diagnostic behavior may be improved by adding the 'format(printf, 2, 0)' attribute to the declaration of 'fn5'}} // expected-note@#S1_fn5 {{'fn5' declared here}} } }; diff --git a/clang/test/Sema/attr-format-missing.m b/clang/test/Sema/attr-format-missing.m new file mode 100644 index 0000000000000..3896bcef4634a --- /dev/null +++ b/clang/test/Sema/attr-format-missing.m @@ -0,0 +1,31 @@ +// RUN: %clang_cc1 -fsyntax-only -verify -Wmissing-format-attribute %s +// RUN: %clang_cc1 -fsyntax-only -Wmissing-format-attribute -fdiagnostics-parseable-fixits %s 2>&1 | FileCheck %s + +#include <stdarg.h> + +@interface Print +-(void)printf:(const char *)fmt, ... __attribute__((format(printf, 1, 2))); +-(void)vprintf:(const char *)fmt list:(va_list)ap __attribute__((format(printf, 1, 0))); +@end + +// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:1-[[@LINE+1]]:1}:"__attribute__((format(printf, 2, 3))) " +void f1(Print *p, const char *fmt, int x) // #f1 +{ + [p printf:fmt, x]; // expected-warning {{diagnostic behavior may be improved by adding the 'format(printf, 2, 3)' attribute to the declaration of 'f1'}} + // expected-note@#f1 {{'f1' declared here}} +} + +// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:1-[[@LINE+1]]:1}:"__attribute__((format(printf, 2, 3))) " +void f2(Print *p, const char *fmt, ...) // #f2 +{ + va_list ap; + [p vprintf:fmt list:ap]; // expected-warning {{diagnostic behavior may be improved by adding the 'format(printf, 2, 3)' attribute to the declaration of 'f2'}} + // expected-note@#f2 {{'f2' declared here}} +} + +// CHECK: fix-it:"{{.*}}":{[[@LINE+1]]:1-[[@LINE+1]]:1}:"__attribute__((format(printf, 2, 0))) " +void f3(Print *p, const char *fmt, va_list ap) // #f3 +{ + [p vprintf:fmt list:ap]; // expected-warning {{diagnostic behavior may be improved by adding the 'format(printf, 2, 0)' attribute to the declaration of 'f3'}} + // expected-note@#f3 {{'f3' declared here}} +} >From ba5e3d8cee04ba236495c8e440688533f93f928d Mon Sep 17 00:00:00 2001 From: Vladimir Vuksanovic <[email protected]> Date: Mon, 17 Nov 2025 00:55:32 -0800 Subject: [PATCH 4/4] Emit fixit only when supported --- clang/lib/Sema/SemaChecking.cpp | 37 +++++++++++++++++++-------------- 1 file changed, 21 insertions(+), 16 deletions(-) diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp index b78aec68bec62..5dbac022d7c4d 100644 --- a/clang/lib/Sema/SemaChecking.cpp +++ b/clang/lib/Sema/SemaChecking.cpp @@ -7070,23 +7070,28 @@ static void CheckMissingFormatAttributes(Sema *S, FormatStringType FormatType, // Emit the diagnostic and fixit. unsigned FormatStringIndex = CallerParamIdx + CallerArgumentIndexOffset; - StringRef AttrPrefix, AttrSuffix; - if (S->getLangOpts().C23 || S->getLangOpts().CPlusPlus11) { - AttrPrefix = "[[gnu::"; - AttrSuffix = "]] "; - } else { - AttrPrefix = "__attribute__(("; - AttrSuffix = ")) "; - } StringRef FormatTypeName = S->GetFormatStringTypeName(FormatType); - std::string Attr = - ("format(" + FormatTypeName + ", " + llvm::Twine(FormatStringIndex) + - ", " + llvm::Twine(FirstArgumentIndex) + ")") - .str(); - S->Diag(Loc, diag::warn_missing_format_attribute) - << Attr << Caller - << FixItHint::CreateInsertion(Caller->getBeginLoc(), - (AttrPrefix + Attr + AttrSuffix).str()); + { + std::string Attr = + ("format(" + FormatTypeName + ", " + llvm::Twine(FormatStringIndex) + + ", " + llvm::Twine(FirstArgumentIndex) + ")") + .str(); + auto DB = S->Diag(Loc, diag::warn_missing_format_attribute) + << Attr << Caller; + const LangOptions &LO = S->getLangOpts(); + StringRef AttrPrefix, AttrSuffix; + if (LO.C23 || LO.CPlusPlus11) { + AttrPrefix = "[[gnu::"; + AttrSuffix = "]] "; + } else if (LO.ObjC || LO.GNUMode) { + AttrPrefix = "__attribute__(("; + AttrSuffix = ")) "; + } + if (!AttrPrefix.empty()) { + DB << FixItHint::CreateInsertion(Caller->getBeginLoc(), + (AttrPrefix + Attr + AttrSuffix).str()); + } + } S->Diag(Caller->getLocation(), diag::note_entity_declared_at) << Caller; } _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
