inclyc updated this revision to Diff 449517.
inclyc added a comment.
.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D130906/new/
https://reviews.llvm.org/D130906
Files:
clang/docs/ReleaseNotes.rst
clang/lib/Sema/SemaChecking.cpp
clang/test/SemaCXX/format-strings.cpp
Index: clang/test/SemaCXX/format-strings.cpp
===================================================================
--- clang/test/SemaCXX/format-strings.cpp
+++ clang/test/SemaCXX/format-strings.cpp
@@ -163,3 +163,48 @@
t::func4("Hello %s"); // expected-warning {{more '%' conversions than data arguments}}
}
}
+#if __cplusplus >= 201103L
+namespace evaluated {
+
+constexpr const char *basic() {
+ return
+"%s %d"; // expected-note {{format string is defined here}}
+}
+
+constexpr const char *correct_fmt() {
+ return
+"%d %d";
+}
+
+constexpr const char *string_linebreak() {
+ return
+"%d %d"
+"%d %s"; // expected-note {{format string is defined here}}
+}
+
+/*non-constexpr*/ const char *not_literal() {
+ return
+"%d %d"
+"%d %s";
+}
+
+constexpr const char *inner_call() {
+ return "%d %s"; // expected-note {{format string is defined here}}
+}
+
+constexpr const char *wrap_constexpr() {
+ return inner_call();
+}
+
+
+void f() {
+ printf(basic(), 1, 2); // expected-warning {{format specifies type 'char *' but the argument has type 'int'}}
+ printf(correct_fmt(), 1, 2);
+ printf(string_linebreak(), 1, 2, 3, 4); // expected-warning {{format specifies type 'char *' but the argument has type 'int'}}
+ printf(not_literal(), 1, 2, 3, 4); // expected-warning {{format string is not a string literal}}
+ printf(wrap_constexpr(), 1, 2); // expected-warning {{format specifies type 'char *' but the argument has type 'int'}}
+}
+
+
+}
+#endif
Index: clang/lib/Sema/SemaChecking.cpp
===================================================================
--- clang/lib/Sema/SemaChecking.cpp
+++ clang/lib/Sema/SemaChecking.cpp
@@ -8473,6 +8473,9 @@
llvm::SmallBitVector &CheckedVarArgs, UncoveredArgHandler &UncoveredArg,
bool IgnoreStringsWithoutSpecifiers);
+static const Expr *maybeConstEvalStringLiteral(ASTContext &Context,
+ const Expr *E);
+
// Determine if an expression is a string literal or constant string.
// If this function returns false on the arguments to a function expecting a
// format string, we will usually need to emit a warning.
@@ -8713,7 +8716,11 @@
}
}
}
-
+ if (auto *SLE = maybeConstEvalStringLiteral(S.Context, E))
+ return checkFormatStringExpr(S, SLE, Args, APK, format_idx, firstDataArg,
+ Type, CallType, /*InFunctionCall*/ false,
+ CheckedVarArgs, UncoveredArg, Offset,
+ IgnoreStringsWithoutSpecifiers);
return SLCT_NotALiteral;
}
case Stmt::ObjCMessageExprClass: {
@@ -8823,6 +8830,20 @@
}
}
+// If this expression can be evaluated at compile-time,
+// check if the result is a StringLiteral and return it
+// otherwise return nullptr
+static const Expr *maybeConstEvalStringLiteral(ASTContext &Context,
+ const Expr *E) {
+ Expr::EvalResult Result;
+ if (E->EvaluateAsRValue(Result, Context) && Result.Val.isLValue()) {
+ auto *LVE = Result.Val.getLValueBase().dyn_cast<const Expr *>();
+ if (isa_and_nonnull<StringLiteral>(LVE))
+ return LVE;
+ }
+ return nullptr;
+}
+
Sema::FormatStringType Sema::GetFormatStringType(const FormatAttr *Format) {
return llvm::StringSwitch<FormatStringType>(Format->getType()->getName())
.Case("scanf", FST_Scanf)
Index: clang/docs/ReleaseNotes.rst
===================================================================
--- clang/docs/ReleaseNotes.rst
+++ clang/docs/ReleaseNotes.rst
@@ -61,6 +61,8 @@
enum without a fixed underlying type is set to a value outside the range of
the enumeration's values. Fixes
`Issue 50055: <https://github.com/llvm/llvm-project/issues/50055>`_.
+- Clang will now check compile-time determinable string literals as format strings.
+ This fixes `Issue 55805: <https://github.com/llvm/llvm-project/issues/55805>`_.
Non-comprehensive list of changes in this release
-------------------------------------------------
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