https://github.com/budimirarandjelovicsyrmia updated
https://github.com/llvm/llvm-project/pull/70024
From 845235ed5bb126458a792bc1051bb5b13b78a677 Mon Sep 17 00:00:00 2001
From: budimirarandjelovicsyrmia <budimir.arandjelo...@syrmia.com>
Date: Fri, 13 Oct 2023 14:45:15 +0200
Subject: [PATCH] [clang] Catch missing format attributes
---
clang/include/clang/Basic/DiagnosticGroups.td | 2 +-
.../clang/Basic/DiagnosticSemaKinds.td | 5 +
clang/include/clang/Sema/Sema.h | 4 +
clang/lib/Sema/SemaChecking.cpp | 4 +-
clang/lib/Sema/SemaDeclAttr.cpp | 104 ++++++++++++++++++
clang/test/Sema/attr-format-missing.c | 13 +++
6 files changed, 130 insertions(+), 2 deletions(-)
create mode 100644 clang/test/Sema/attr-format-missing.c
diff --git a/clang/include/clang/Basic/DiagnosticGroups.td
b/clang/include/clang/Basic/DiagnosticGroups.td
index 17fdcffa2d42740..b8b77df84beb2be 100644
--- a/clang/include/clang/Basic/DiagnosticGroups.td
+++ b/clang/include/clang/Basic/DiagnosticGroups.td
@@ -482,7 +482,7 @@ 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 MissingFormatAttribute: DiagGroup<"missing-format-attribute">;
def : 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 6d6f474f6dcdab9..6864fe3057a1df9 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -936,6 +936,11 @@ def err_opencl_invalid_param : Error<
def err_opencl_invalid_return : Error<
"declaring function return value of type %0 is not allowed %select{; did you
forget * ?|}1">;
def warn_enum_value_overflow : Warning<"overflow in enumeration value">;
+def warn_missing_format_attribute : Warning<
+ "diagnostic behavior may be improved by adding the %0 format attribute to
the declaration of %1">,
+ InGroup<MissingFormatAttribute>, DefaultIgnore;
+def note_insert_format_attribute_fixit: Note<
+ "insert %0 to silence this warning">;
def warn_pragma_options_align_reset_failed : Warning<
"#pragma options align=reset failed: %0">,
InGroup<IgnoredPragmas>;
diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index 741c2503127af7a..064506e70960333 100644
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -10615,6 +10615,10 @@ class Sema final {
ChangedStateAtExit
};
+ void DiagnoseMissingFormatAttributes(const FunctionDecl *FDecl,
+ ArrayRef<const Expr *> Args,
+ SourceLocation Loc);
+
void DiagnoseNonDefaultPragmaAlignPack(PragmaAlignPackDiagnoseKind Kind,
SourceLocation IncludeLoc);
void DiagnoseUnterminatedPragmaAlignPack();
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 4602284309491c1..d3ac6cb519c56ed 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -6014,8 +6014,10 @@ void Sema::checkCall(NamedDecl *FDecl, const
FunctionProtoType *Proto,
}
}
- if (FD)
+ if (FD) {
diagnoseArgDependentDiagnoseIfAttrs(FD, ThisArg, Args, Loc);
+ DiagnoseMissingFormatAttributes(FD, Args, Range.getBegin());
+ }
}
/// CheckConstructorCall - Check a constructor call for correctness and safety
diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
index 1a0bfb3d91bcc87..afa9648fdf0069e 100644
--- a/clang/lib/Sema/SemaDeclAttr.cpp
+++ b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -6849,6 +6849,110 @@ static void handleSwiftAsyncAttr(Sema &S, Decl *D,
const ParsedAttr &AL) {
checkSwiftAsyncErrorBlock(S, D, ErrorAttr, AsyncAttr);
}
+// Warn if passed function has format attribute and their parent not.
+void Sema::DiagnoseMissingFormatAttributes(const FunctionDecl *FDecl,
+ ArrayRef<const Expr *> Args,
+ SourceLocation Loc) {
+ assert(FDecl);
+
+ unsigned BuiltinID = FDecl->getBuiltinID(/*ConsiderWrappers=*/true);
+
+ // If function is builtin and not listed in switch, exit.
+ switch (BuiltinID) {
+ case Builtin::NotBuiltin:
+ break;
+ case Builtin::BIprintf:
+ case Builtin::BIfprintf:
+ case Builtin::BIsprintf:
+ case Builtin::BIscanf:
+ case Builtin::BIfscanf:
+ case Builtin::BIsscanf:
+ case Builtin::BIvprintf:
+ case Builtin::BIvfprintf:
+ case Builtin::BIvsprintf:
+ break;
+ // C99 mode
+ case Builtin::BIsnprintf:
+ case Builtin::BIvsnprintf:
+ case Builtin::BIvscanf:
+ case Builtin::BIvfscanf:
+ case Builtin::BIvsscanf:
+ if (!getLangOpts().C99)
+ return;
+ break;
+ default:
+ return;
+ }
+
+ const FunctionDecl *ParentFuncDecl = getCurFunctionDecl();
+ if (!ParentFuncDecl)
+ return;
+
+ // Iterate through function format attributes. Check if parent function
+ // has these attributes. If parent function does not have format
+ // attribute, emit warning.
+ for (const FormatAttr *Attr : FDecl->specific_attrs<FormatAttr>()) {
+ // Check if parent function has format attribute with correct arguments.
+ bool HasCorrectFormatAttr = llvm::any_of(
+ ParentFuncDecl->specific_attrs<FormatAttr>(),
+ [&](const FormatAttr *ParentAttr) {
+ // Check if first argument matches child function format argument
+ // type.
+ if (ParentAttr->getType() != Attr->getType())
+ return false;
+
+ // In C++ the implicit 'this' function parameter also counts
+ // Number of arguments does not count variadic argument
+ unsigned NumArgs = getFunctionOrMethodNumParams(ParentFuncDecl) +
+ isInstanceMethod(ParentFuncDecl);
+
+ // Checks for second argument
+ unsigned FormatIdx = ParentAttr->getFormatIdx();
+ if (FormatIdx < 1 || FormatIdx > NumArgs)
+ return false;
+
+ // Check if second argument matches correct type.
+ QualType FormatType =
+ ParentFuncDecl->parameters()[FormatIdx - 1]->getType();
+ if (!isNSStringType(FormatType, Context, true) &&
+ !isCFStringType(FormatType, Context) &&
+ (!FormatType->isPointerType() ||
+ !FormatType->getPointeeType()->isCharType()))
+ return false;
+
+ // Check third argument, which is valid if it is either zero
+ // or greater by one than number of parent function arguments.
+ unsigned FirstArg = ParentAttr->getFirstArg();
+ return FirstArg == 0 || FirstArg == NumArgs + 1;
+ });
+
+ if (HasCorrectFormatAttr)
+ continue;
+
+ Diag(Loc, diag::warn_missing_format_attribute)
+ << Attr->getType() << ParentFuncDecl;
+
+ int StringIndex = 0;
+ for (ParmVarDecl *Param : ParentFuncDecl->parameters()) {
+ if (Param->getType() == Args[Attr->getFirstArg()]->getType()) {
+ StringIndex = Param->getFunctionScopeIndex() + 1;
+ break;
+ }
+ }
+
+ int FirstToCheck =
+ ParentFuncDecl->isVariadic() ? (ParentFuncDecl->getNumParams() + 1) :
0;
+ SourceLocation ParentFuncLoc = ParentFuncDecl->getLocation();
+ std::string InsertionText;
+ llvm::raw_string_ostream OS(InsertionText);
+ OS << "__attribute__((format(" + Attr->getType()->getName() + ", " +
+ std::to_string(StringIndex) + ", " +
+ std::to_string(FirstToCheck) + ")))";
+ Diag(ParentFuncLoc, diag::note_insert_format_attribute_fixit)
+ << FixItHint::CreateInsertion(ParentFuncLoc, InsertionText);
+ }
+}
+
//===----------------------------------------------------------------------===//
// Microsoft specific attribute handlers.
//===----------------------------------------------------------------------===//
diff --git a/clang/test/Sema/attr-format-missing.c
b/clang/test/Sema/attr-format-missing.c
new file mode 100644
index 000000000000000..1926d3d3163124b
--- /dev/null
+++ b/clang/test/Sema/attr-format-missing.c
@@ -0,0 +1,13 @@
+// RUN: %clang_cc1 -fsyntax-only -verify -Wmissing-format-attribute %s
+// RUN: %clang_cc1 -fsyntax-only -verify -std=c99 -Wmissing-format-attribute %s
+
+#include <stdarg.h>
+#include <stdio.h>
+
+__attribute__((__format__ (__scanf__, 1, 4)))
+void foo(char *out, const size_t len, const char *format, ... /* args */)
+{
+ va_list args;
+
+ vsnprintf(out, len, format, args); // expected-warning {{Function 'foo'
might be candidate for 'printf' format attribute}}
+}
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
