[PATCH] D137839: [Sema] check InitListExpr format strings like {"foo"}

[Yingchi Long via Phabricator via cfe-commits]

inclyc created this revision.
Herald added a project: All.
inclyc added a reviewer: aaron.ballman.
inclyc published this revision for review.
Herald added a project: clang.
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Adds InitListExpr case in format string checks.

e.g.

  int sprintf(char *__restrict, const char * __restrict, ...);
  
  int foo()
  {
      char data[100];
      constexpr const char* fmt2{"%d"};  // no-warning
      sprintf(data, fmt2, 123);
  }

Fixes: https://github.com/llvm/llvm-project/issues/58900


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D137839

Files:
  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
@@ -203,6 +203,9 @@
   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'}}
+
+  constexpr const char *fmt {"%d%d"};
+  printf(fmt, 1, 1); // no-warning
 }
 
 
Index: clang/lib/Sema/SemaChecking.cpp
===================================================================
--- clang/lib/Sema/SemaChecking.cpp
+++ clang/lib/Sema/SemaChecking.cpp
@@ -8554,6 +8554,15 @@
     return SLCT_UncheckedLiteral;
 
   switch (E->getStmtClass()) {
+  case Stmt::InitListExprClass:
+    // Handle expressions like {"foobar"}.
+    if (const clang::Expr *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::BinaryConditionalOperatorClass:
   case Stmt::ConditionalOperatorClass: {
     // The expression is a literal if both sub-expressions were, and it was


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