[clang] [clang][Sema] Fixes for %b printf extension handling (PR #120689)

[Brad Smith via cfe-commits]

https://github.com/brad0 created https://github.com/llvm/llvm-project/pull/120689

The %b printf extension in the kernel is not fixed to a int type. On
sparc64 there are various %llb formats. Adjust the code to handle the
length specifiers and type check like it is used by the regular case.

>From a0b6bab87a50cd0c66d8c31ca2f16376de826955 Mon Sep 17 00:00:00 2001
From: Brad Smith <brad at comstyle.com>
Date: Thu, 19 Dec 2024 21:35:57 -0500
Subject: [PATCH] [clang][Sema] Fixes for %b printf extension handling

The %b printf extension in the kernel is not fixed to a int type. On
sparc64 there are various %llb formats. Adjust the code to handle the
length specifiers and type check like it is used by the regular case.
---
 clang/lib/Sema/SemaChecking.cpp | 33 ++++++++++++++++++++++++---------
 1 file changed, 24 insertions(+), 9 deletions(-)

diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index f6c4def2892554..93a09ac65b8cad 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -7191,18 +7191,33 @@ bool CheckPrintfHandler::HandlePrintfSpecifier(
     // Claim the second argument.
     CoveredArgs.set(argIndex + 1);
 
-    // Type check the first argument (int for %b, pointer for %D)
     const Expr *Ex = getDataArg(argIndex);
-    const analyze_printf::ArgType &AT =
-      (CS.getKind() == ConversionSpecifier::FreeBSDbArg) ?
-        ArgType(S.Context.IntTy) : ArgType::CPointerTy;
-    if (AT.isValid() && !AT.matchesType(S.Context, Ex->getType()))
-      EmitFormatDiagnostic(
+    if (CS.getKind() == ConversionSpecifier::FreeBSDDArg) {
+      // Type check the first argument (pointer for %D)
+      const analyze_printf::ArgType &AT = ArgType::CPointerTy;
+      if (AT.isValid() && !AT.matchesType(S.Context, Ex->getType()))
+        EmitFormatDiagnostic(
           S.PDiag(diag::warn_format_conversion_argument_type_mismatch)
-              << AT.getRepresentativeTypeName(S.Context) << Ex->getType()
-              << false << Ex->getSourceRange(),
-          Ex->getBeginLoc(), /*IsStringLocation*/ false,
+          << AT.getRepresentativeTypeName(S.Context) << Ex->getType()
+          << false << Ex->getSourceRange(),
+          Ex->getBeginLoc(), /*IsStringLocation*/false,
           getSpecifierRange(startSpecifier, specifierLen));
+    } else {
+      // Check the length modifier for %b
+      if (!FS.hasValidLengthModifier(S.getASTContext().getTargetInfo(),
+                                     S.getLangOpts()))
+        HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen,
+                                    diag::warn_format_nonsensical_length);
+      else if (!FS.hasStandardLengthModifier())
+        HandleNonStandardLengthModifier(FS, startSpecifier, specifierLen);
+      else if (!FS.hasStandardLengthConversionCombination())
+        HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen,
+                                    diag::warn_format_non_standard_conversion_spec);
+
+      // Type check the first argument of %b
+      if (!checkFormatExpr(FS, startSpecifier, specifierLen, Ex))
+        return false;
+    }
 
     // Type check the second argument (char * for both %b and %D)
     Ex = getDataArg(argIndex + 1);