[Sema] -Wformat-pedantic only for NSInteger/NSUInteger %zu/%zi on Darwin

Summary:
Pick D42933 back up, and make NSInteger/NSUInteger with %zu/%zi specifiers on Darwin warn only in pedantic mode. The default -Wformat recently started warning for the following code because of the added support for analysis for the '%zi' specifier.

     NSInteger i = NSIntegerMax;
     NSLog(@"max NSInteger = %zi", i);

The problem is that on armv7 %zi is 'long', and NSInteger is typedefed to 'int' in Foundation. We should avoid this warning as it's inconvenient to our users: it's target specific (happens only on armv7 and not arm64), and breaks their existing code. We should also silence the warning for the '%zu' specifier to ensure consistency. This is acceptable because Darwin guarantees that, despite the unfortunate choice of typedef, sizeof(size_t) == sizeof(NS[U]Integer), the warning is therefore noisy for pedantic reasons. Once this is in I'll update public documentation.

Related discussion on cfe-dev:
http://lists.llvm.org/pipermail/cfe-dev/2018-May/058050.html

<rdar://36874921&40501559>

Reviewers: ahatanak, vsapsai, alexshap, aaron.ballman, javed.absar, jfb, rjmccall

Subscribers: kristof.beyls, aheejin, cfe-commits

Differential Revision: https://reviews.llvm.org/D47290

llvm-svn: 335393

7 files changed, 109 insertions, 40 deletions

diff --git a/clang/include/clang/Analysis/Analyses/FormatString.h b/clang/include/clang/Analysis/Analyses/FormatString.h
index a23aaae7662..6d76718048b 100644
--- a/clang/include/clang/Analysis/Analyses/FormatString.h
+++ b/clang/include/clang/Analysis/Analyses/FormatString.h
@@ -256,18 +256,19 @@ public:
 private:
   const Kind K;
   QualType T;
-  const char *Name;
-  bool Ptr;
+  const char *Name = nullptr;
+  bool Ptr = false, IsSizeT = false;
+
 public:
-  ArgType(Kind k = UnknownTy, const char *n = nullptr)
-      : K(k), Name(n), Ptr(false) {}
-  ArgType(QualType t, const char *n = nullptr)
-      : K(SpecificTy), T(t), Name(n), Ptr(false) {}
-  ArgType(CanQualType t) : K(SpecificTy), T(t), Name(nullptr), Ptr(false) {}
+  ArgType(Kind K = UnknownTy, const char *N = nullptr) : K(K), Name(N) {}
+  ArgType(QualType T, const char *N = nullptr) : K(SpecificTy), T(T), Name(N) {}
+  ArgType(CanQualType T) : K(SpecificTy), T(T) {}
 
   static ArgType Invalid() { return ArgType(InvalidTy); }
   bool isValid() const { return K != InvalidTy; }
 
+  bool isSizeT() const { return IsSizeT; }
+
   /// Create an ArgType which corresponds to the type pointer to A.
   static ArgType PtrTo(const ArgType& A) {
     assert(A.K >= InvalidTy && "ArgType cannot be pointer to invalid/unknown");
@@ -276,6 +277,13 @@ public:
     return Res;
   }
 
+  /// Create an ArgType which corresponds to the size_t/ssize_t type.
+  static ArgType makeSizeT(const ArgType &A) {
+    ArgType Res = A;
+    Res.IsSizeT = true;
+    return Res;
+  }
+
   MatchKind matchesType(ASTContext &C, QualType argTy) const;
 
   QualType getRepresentativeType(ASTContext &C) const;
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index b7ede8518ee..f08cd00c62e 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -7719,6 +7719,10 @@ def warn_format_argument_needs_cast : Warning<
   "%select{values of type|enum values with underlying type}2 '%0' should not "
   "be used as format arguments; add an explicit cast to %1 instead">,
   InGroup<Format>;
+def warn_format_argument_needs_cast_pedantic : Warning<
+  "%select{values of type|enum values with underlying type}2 '%0' should not "
+  "be used as format arguments; add an explicit cast to %1 instead">,
+  InGroup<FormatPedantic>, DefaultIgnore;
 def warn_printf_positional_arg_exceeds_data_args : Warning <
   "data argument position '%0' exceeds the number of data arguments (%1)">,
   InGroup<Format>;
diff --git a/clang/lib/Analysis/PrintfFormatString.cpp b/clang/lib/Analysis/PrintfFormatString.cpp
index 3b64508b5a6..93d64f03ead 100644
--- a/clang/lib/Analysis/PrintfFormatString.cpp
+++ b/clang/lib/Analysis/PrintfFormatString.cpp
@@ -466,7 +466,7 @@ ArgType PrintfSpecifier::getArgType(ASTContext &Ctx,
       case LengthModifier::AsIntMax:
         return ArgType(Ctx.getIntMaxType(), "intmax_t");
       case LengthModifier::AsSizeT:
-        return ArgType(Ctx.getSignedSizeType(), "ssize_t");
+        return ArgType::makeSizeT(ArgType(Ctx.getSignedSizeType(), "ssize_t"));
       case LengthModifier::AsInt3264:
         return Ctx.getTargetInfo().getTriple().isArch64Bit()
                    ? ArgType(Ctx.LongLongTy, "__int64")
@@ -499,7 +499,7 @@ ArgType PrintfSpecifier::getArgType(ASTContext &Ctx,
       case LengthModifier::AsIntMax:
         return ArgType(Ctx.getUIntMaxType(), "uintmax_t");
       case LengthModifier::AsSizeT:
-        return ArgType(Ctx.getSizeType(), "size_t");
+        return ArgType::makeSizeT(ArgType(Ctx.getSizeType(), "size_t"));
       case LengthModifier::AsInt3264:
         return Ctx.getTargetInfo().getTriple().isArch64Bit()
                    ? ArgType(Ctx.UnsignedLongLongTy, "unsigned __int64")
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 53be0f6d9ff..12a599b4f13 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -6805,11 +6805,11 @@ CheckPrintfHandler::checkFormatExpr(const analyze_printf::PrintfSpecifier &FS,
     ExprTy = TET->getUnderlyingExpr()->getType();
   }
 
-  analyze_printf::ArgType::MatchKind match = AT.matchesType(S.Context, ExprTy);
-
-  if (match == analyze_printf::ArgType::Match) {
+  const analyze_printf::ArgType::MatchKind Match =
+      AT.matchesType(S.Context, ExprTy);
+  bool Pedantic = Match == analyze_printf::ArgType::NoMatchPedantic;
+  if (Match == analyze_printf::ArgType::Match)
     return true;
-  }
 
   // Look through argument promotions for our error message's reported type.
   // This includes the integral and floating promotions, but excludes array
@@ -6885,6 +6885,11 @@ CheckPrintfHandler::checkFormatExpr(const analyze_printf::PrintfSpecifier &FS,
     QualType CastTy;
     std::tie(CastTy, CastTyName) = shouldNotPrintDirectly(S.Context, IntendedTy, E);
     if (!CastTy.isNull()) {
+      // %zi/%zu are OK to use for NSInteger/NSUInteger of type int
+      // (long in ASTContext). Only complain to pedants.
+      if ((CastTyName == "NSInteger" || CastTyName == "NSUInteger") &&
+          AT.isSizeT() && AT.matchesType(S.Context, CastTy))
+        Pedantic = true;
       IntendedTy = CastTy;
       ShouldNotPrintDirectly = true;
     }
@@ -6892,10 +6897,10 @@ CheckPrintfHandler::checkFormatExpr(const analyze_printf::PrintfSpecifier &FS,
 
   // We may be able to offer a FixItHint if it is a supported type.
   PrintfSpecifier fixedFS = FS;
-  bool success =
+  bool Success =
       fixedFS.fixType(IntendedTy, S.getLangOpts(), S.Context, isObjCContext());
 
-  if (success) {
+  if (Success) {
     // Get the fix string from the fixed format specifier
     SmallString<16> buf;
     llvm::raw_svector_ostream os(buf);
@@ -6904,13 +6909,13 @@ CheckPrintfHandler::checkFormatExpr(const analyze_printf::PrintfSpecifier &FS,
     CharSourceRange SpecRange = getSpecifierRange(StartSpecifier, SpecifierLen);
 
     if (IntendedTy == ExprTy && !ShouldNotPrintDirectly) {
-      unsigned diag = diag::warn_format_conversion_argument_type_mismatch;
-      if (match == analyze_format_string::ArgType::NoMatchPedantic) {
-        diag = diag::warn_format_conversion_argument_type_mismatch_pedantic;
-      }
+      unsigned Diag =
+          Pedantic
+              ? diag::warn_format_conversion_argument_type_mismatch_pedantic
+              : diag::warn_format_conversion_argument_type_mismatch;
       // In this case, the specifier is wrong and should be changed to match
       // the argument.
-      EmitFormatDiagnostic(S.PDiag(diag)
+      EmitFormatDiagnostic(S.PDiag(Diag)
                                << AT.getRepresentativeTypeName(S.Context)
                                << IntendedTy << IsEnum << E->getSourceRange(),
                            E->getLocStart(),
@@ -6963,9 +6968,11 @@ CheckPrintfHandler::checkFormatExpr(const analyze_printf::PrintfSpecifier &FS,
           Name = TypedefTy->getDecl()->getName();
         else
           Name = CastTyName;
-        EmitFormatDiagnostic(S.PDiag(diag::warn_format_argument_needs_cast)
-                               << Name << IntendedTy << IsEnum
-                               << E->getSourceRange(),
+        unsigned Diag = Pedantic
+                            ? diag::warn_format_argument_needs_cast_pedantic
+                            : diag::warn_format_argument_needs_cast;
+        EmitFormatDiagnostic(S.PDiag(Diag) << Name << IntendedTy << IsEnum
+                                           << E->getSourceRange(),
                              E->getLocStart(), /*IsStringLocation=*/false,
                              SpecRange, Hints);
       } else {
@@ -6989,13 +6996,13 @@ CheckPrintfHandler::checkFormatExpr(const analyze_printf::PrintfSpecifier &FS,
     switch (S.isValidVarArgType(ExprTy)) {
     case Sema::VAK_Valid:
     case Sema::VAK_ValidInCXX11: {
-      unsigned diag = diag::warn_format_conversion_argument_type_mismatch;
-      if (match == analyze_printf::ArgType::NoMatchPedantic) {
-        diag = diag::warn_format_conversion_argument_type_mismatch_pedantic;
-      }
+      unsigned Diag =
+          Pedantic
+              ? diag::warn_format_conversion_argument_type_mismatch_pedantic
+              : diag::warn_format_conversion_argument_type_mismatch;
 
       EmitFormatDiagnostic(
-          S.PDiag(diag) << AT.getRepresentativeTypeName(S.Context) << ExprTy
+          S.PDiag(Diag) << AT.getRepresentativeTypeName(S.Context) << ExprTy
                         << IsEnum << CSR << E->getSourceRange(),
           E->getLocStart(), /*IsStringLocation*/ false, CSR);
       break;
@@ -7178,29 +7185,28 @@ bool CheckScanfHandler::HandleScanfSpecifier(
     return true;
   }
 
-  analyze_format_string::ArgType::MatchKind match =
+  analyze_format_string::ArgType::MatchKind Match =
       AT.matchesType(S.Context, Ex->getType());
-  if (match == analyze_format_string::ArgType::Match) {
+  bool Pedantic = Match == analyze_format_string::ArgType::NoMatchPedantic;
+  if (Match == analyze_format_string::ArgType::Match)
     return true;
-  }
 
   ScanfSpecifier fixedFS = FS;
-  bool success = fixedFS.fixType(Ex->getType(), Ex->IgnoreImpCasts()->getType(),
+  bool Success = fixedFS.fixType(Ex->getType(), Ex->IgnoreImpCasts()->getType(),
                                  S.getLangOpts(), S.Context);
 
-  unsigned diag = diag::warn_format_conversion_argument_type_mismatch;
-  if (match == analyze_format_string::ArgType::NoMatchPedantic) {
-    diag = diag::warn_format_conversion_argument_type_mismatch_pedantic;
-  }
+  unsigned Diag =
+      Pedantic ? diag::warn_format_conversion_argument_type_mismatch_pedantic
+               : diag::warn_format_conversion_argument_type_mismatch;
 
-  if (success) {
+  if (Success) {
     // Get the fix string from the fixed format specifier.
     SmallString<128> buf;
     llvm::raw_svector_ostream os(buf);
     fixedFS.toString(os);
 
     EmitFormatDiagnostic(
-        S.PDiag(diag) << AT.getRepresentativeTypeName(S.Context)
+        S.PDiag(Diag) << AT.getRepresentativeTypeName(S.Context)
                       << Ex->getType() << false << Ex->getSourceRange(),
         Ex->getLocStart(),
         /*IsStringLocation*/ false,
@@ -7208,7 +7214,7 @@ bool CheckScanfHandler::HandleScanfSpecifier(
         FixItHint::CreateReplacement(
             getSpecifierRange(startSpecifier, specifierLen), os.str()));
   } else {
-    EmitFormatDiagnostic(S.PDiag(diag)
+    EmitFormatDiagnostic(S.PDiag(Diag)
                              << AT.getRepresentativeTypeName(S.Context)
                              << Ex->getType() << false << Ex->getSourceRange(),
                          Ex->getLocStart(),
diff --git a/clang/test/FixIt/fixit-format-ios-nopedantic.m b/clang/test/FixIt/fixit-format-ios-nopedantic.m
new file mode 100644
index 00000000000..0b332376c06
--- /dev/null
+++ b/clang/test/FixIt/fixit-format-ios-nopedantic.m
@@ -0,0 +1,21 @@
+// RUN: cp %s %t
+// RUN: %clang_cc1 -triple thumbv7-apple-ios8.0.0 -fsyntax-only -Wformat -Werror -fixit %t
+
+int printf(const char *restrict, ...);
+typedef unsigned int NSUInteger;
+typedef int NSInteger;
+NSUInteger getNSUInteger();
+NSInteger getNSInteger();
+
+void test() {
+  // For thumbv7-apple-ios8.0.0 the underlying type of ssize_t is long
+  // and the underlying type of size_t is unsigned long.
+
+  printf("test 1: %zu", getNSUInteger());
+
+  printf("test 2: %zu %zu", getNSUInteger(), getNSUInteger());
+
+  printf("test 3: %zd", getNSInteger());
+
+  printf("test 4: %zd %zd", getNSInteger(), getNSInteger());
+}
diff --git a/clang/test/FixIt/fixit-format-ios.m b/clang/test/FixIt/fixit-format-ios.m
index ef664307786..9c3670d0c84 100644
--- a/clang/test/FixIt/fixit-format-ios.m
+++ b/clang/test/FixIt/fixit-format-ios.m
@@ -1,5 +1,5 @@
 // RUN: cp %s %t
-// RUN: %clang_cc1 -triple thumbv7-apple-ios8.0.0 -fsyntax-only -Wformat -fixit %t
+// RUN: %clang_cc1 -triple thumbv7-apple-ios8.0.0 -fsyntax-only -Wformat-pedantic -fixit %t
 // RUN: grep -v CHECK %t | FileCheck %s
 
 int printf(const char * restrict, ...);
diff --git a/clang/test/SemaObjC/format-size-spec-nsinteger.m b/clang/test/SemaObjC/format-size-spec-nsinteger.m
new file mode 100644
index 00000000000..9eb954ec512
--- /dev/null
+++ b/clang/test/SemaObjC/format-size-spec-nsinteger.m
@@ -0,0 +1,30 @@
+// RUN: %clang_cc1 -triple thumbv7-apple-ios -Wno-objc-root-class -fsyntax-only -verify -Wformat %s
+// RUN: %clang_cc1 -triple thumbv7-apple-ios -Wno-objc-root-class -fsyntax-only -verify -Wformat-pedantic -DPEDANTIC %s
+
+#if !defined(PEDANTIC)
+// expected-no-diagnostics
+#endif
+
+#if __LP64__
+typedef unsigned long NSUInteger;
+typedef long NSInteger;
+#else
+typedef unsigned int NSUInteger;
+typedef int NSInteger;
+#endif
+
+@class NSString;
+
+extern void NSLog(NSString *format, ...);
+
+void testSizeSpecifier() {
+  NSInteger i = 0;
+  NSUInteger j = 0;
+  NSLog(@"max NSInteger = %zi", i);
+  NSLog(@"max NSUinteger = %zu", j);
+
+#if defined(PEDANTIC)
+  // expected-warning@-4 {{values of type 'NSInteger' should not be used as format arguments; add an explicit cast to 'long' instead}}
+  // expected-warning@-4 {{values of type 'NSUInteger' should not be used as format arguments; add an explicit cast to 'unsigned long' instead}}
+#endif
+}