[clang] [clang] Implement __attribute__((format_matches)) (PR #116708)

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=?utf-8?q?Félix?= Cloutier <fcloutier at apple.com>,
=?utf-8?q?Félix?= Cloutier <fcloutier at apple.com>,
=?utf-8?q?Félix?= Cloutier <fcloutier at apple.com>,
=?utf-8?q?Félix?= Cloutier <fcloutier at apple.com>,
=?utf-8?q?Félix?= Cloutier <fcloutier at apple.com>,
=?utf-8?q?Félix?= Cloutier <fcloutier at apple.com>,
=?utf-8?q?Félix?= Cloutier <fcloutier at apple.com>,
=?utf-8?q?Félix?= Cloutier <fcloutier at apple.com>,
=?utf-8?q?Félix?= Cloutier <fcloutier at apple.com>
Message-ID:
In-Reply-To: <llvm.org/llvm/llvm-project/pull/116708 at github.com>


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@@ -8664,6 +8664,39 @@ bool Sema::CheckFormatStringsCompatible(
   return false;
 }
 
+bool Sema::ValidateFormatString(FormatStringType Type,
+                                const StringLiteral *Str) {
+  if (Type != Sema::FST_Printf && Type != Sema::FST_NSString &&
+      Type != Sema::FST_Kprintf && Type != Sema::FST_FreeBSDKPrintf &&
+      Type != Sema::FST_OSLog && Type != Sema::FST_OSTrace &&
+      Type != Sema::FST_Syslog)
+    return true;
+
+  FormatStringLiteral RefLit = Str;
+  llvm::SmallVector<EquatableFormatArgument, 9> Args;
+  bool IsObjC = Type == Sema::FST_NSString || Type == Sema::FST_OSTrace;
+  if (!DecomposePrintfHandler::GetSpecifiers(*this, &RefLit, Str, Type, IsObjC,
+                                             true, Args))
+    return false;
+
+  // If positional arguments are used multiple times in the same format string,
+  // ensure that they are used in compatible ways.
+  bool HadError = false;
+  auto Iter = Args.begin();
+  auto End = Args.end();
+  while (Iter != End) {
----------------
apple-fcloutier wrote:

(FWIW, this is the same thing as the other place you commented, but I moved it around between two commits)

https://github.com/llvm/llvm-project/pull/116708