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

[Brad Smith via cfe-commits]

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

>From db61e7cc93b93bfa4ea19b274532f562b3c0a9a6 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          | 38 +++++++++++++++++-------
 clang/test/Sema/format-strings-freebsd.c |  1 -
 2 files changed, 27 insertions(+), 12 deletions(-)

diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index e703a62ff9cf18..e50118762fff32 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -7170,18 +7170,34 @@ 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(
-          S.PDiag(diag::warn_format_conversion_argument_type_mismatch)
-              << AT.getRepresentativeTypeName(S.Context) << Ex->getType()
-              << false << Ex->getSourceRange(),
-          Ex->getBeginLoc(), /*IsStringLocation*/ false,
-          getSpecifierRange(startSpecifier, specifierLen));
+    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,
+            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);
diff --git a/clang/test/Sema/format-strings-freebsd.c b/clang/test/Sema/format-strings-freebsd.c
index 3d3ed6b40f48dc..ce24855b409c90 100644
--- a/clang/test/Sema/format-strings-freebsd.c
+++ b/clang/test/Sema/format-strings-freebsd.c
@@ -10,7 +10,6 @@ void check_freebsd_kernel_extensions(int i, long l, char *s, short h)
 {
   // %b expects an int and a char *
   freebsd_kernel_printf("reg=%b\n", i, "\10\2BITTWO\1BITONE\n"); // no-warning
-  freebsd_kernel_printf("reg=%b\n", l, "\10\2BITTWO\1BITONE\n"); // expected-warning{{format specifies type 'int' but the argument has type 'long'}}
   freebsd_kernel_printf("reg=%b\n", i, l); // expected-warning{{format specifies type 'char *' but the argument has type 'long'}}
   freebsd_kernel_printf("reg=%b\n", i); // expected-warning{{more '%' conversions than data arguments}}
   freebsd_kernel_printf("reg=%b\n", i, "\10\2BITTWO\1BITONE\n", l); // expected-warning{{data argument not used by format string}}