[clang-tidy] Add portability-avoid-platform-specific-fundamental-types

clang-tools-extra/clang-tidy/portability/AvoidPlatformSpecificFundamentalTypesCheck.cpp

@@ -0,0 +1,254 @@
+//===--- AvoidPlatformSpecificFundamentalTypesCheck.cpp - clang-tidy ------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "AvoidPlatformSpecificFundamentalTypesCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/Type.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/ASTMatchers/ASTMatchers.h"
+#include "clang/Basic/TargetInfo.h"
+
+using namespace clang::ast_matchers;
+
+namespace {
+
+static bool isCharType(const clang::BuiltinType *BT) {
+  using clang::BuiltinType;
+  switch (BT->getKind()) {
+  case BuiltinType::Char_S:
+  case BuiltinType::Char_U:
+  case BuiltinType::SChar:
+  case BuiltinType::UChar:
+    return true;
+  default:
+    return false;
+  }
+}
+
+AST_MATCHER(clang::QualType, isBuiltinInt) {
+  const auto *BT = Node->getAs<clang::BuiltinType>();
+  if (!BT)
+    return false;
+
+  switch (BT->getKind()) {
+  case clang::BuiltinType::Short:
+  case clang::BuiltinType::UShort:
+  case clang::BuiltinType::Int:
+  case clang::BuiltinType::UInt:
+  case clang::BuiltinType::Long:
+  case clang::BuiltinType::ULong:
+  case clang::BuiltinType::LongLong:
+  case clang::BuiltinType::ULongLong:
+    return true;
+  default:
+    return false;
+  }
+}
+
+AST_MATCHER(clang::QualType, isBuiltinFloat) {
+  const auto *BT = Node->getAs<clang::BuiltinType>();
+  if (!BT)
+    return false;
+
+  switch (BT->getKind()) {
+  case clang::BuiltinType::Half:
+  case clang::BuiltinType::BFloat16:
+  case clang::BuiltinType::Float:
+  case clang::BuiltinType::Double:
+  case clang::BuiltinType::LongDouble:
+    return true;
+  default:
+    return false;
+  }
+}
+
+AST_MATCHER(clang::QualType, isBuiltinChar) {
+  const auto *BT = Node->getAs<clang::BuiltinType>();
+  if (!BT)
+    return false;
+
+  return isCharType(BT);
+}
+} // namespace
+
+namespace clang::tidy::portability {
+
+AvoidPlatformSpecificFundamentalTypesCheck::
+    AvoidPlatformSpecificFundamentalTypesCheck(StringRef Name,
+                                               ClangTidyContext *Context)
+    : ClangTidyCheck(Name, Context),
+      WarnOnFloats(Options.get("WarnOnFloats", true)),
+      WarnOnInts(Options.get("WarnOnInts", true)),
+      WarnOnChars(Options.get("WarnOnChars", true)),
+      IncludeInserter(Options.getLocalOrGlobal("IncludeStyle",
+                                               utils::IncludeSorter::IS_LLVM),
+                      areDiagsSelfContained()) {}
+
+void AvoidPlatformSpecificFundamentalTypesCheck::registerPPCallbacks(
+    const SourceManager &SM, Preprocessor *PP, Preprocessor *ModuleExpanderPP) {
+  IncludeInserter.registerPreprocessor(PP);
+}
+
+void AvoidPlatformSpecificFundamentalTypesCheck::storeOptions(
+    ClangTidyOptions::OptionMap &Opts) {
+  Options.store(Opts, "WarnOnFloats", WarnOnFloats);
+  Options.store(Opts, "WarnOnInts", WarnOnInts);
+  Options.store(Opts, "WarnOnChars", WarnOnChars);
+  Options.store(Opts, "IncludeStyle", IncludeInserter.getStyle());
+}
+
+static std::string getFloatReplacement(const BuiltinType *BT,
+                                       ASTContext &Context) {
+  const TargetInfo &Target = Context.getTargetInfo();
+
+  auto GetReplacementType = [](unsigned Width) {
+    switch (Width) {
+    // This is ambiguous by default since it could be bfloat16 or float16
+    case 16U:
+      return "";
+    case 32U:
+      return "float32_t";
+    case 64U:
+      return "float64_t";
+    case 128U:
+      return "float128_t";
+    default:
+      return "";
+    }
+  };
+
+  switch (BT->getKind()) {
+  // Not an ambiguous type
+  case BuiltinType::BFloat16:
+    return "bfloat16_t";
+  case BuiltinType::Half:
+    return GetReplacementType(Target.getHalfWidth());
+  case BuiltinType::Float:
+    return GetReplacementType(Target.getFloatWidth());
+  case BuiltinType::Double:
+    return GetReplacementType(Target.getDoubleWidth());
+  default:
+    return "";
+  }
+}
+
+void AvoidPlatformSpecificFundamentalTypesCheck::registerMatchers(
+    MatchFinder *Finder) {
+  auto PlatformSpecificFundamentalType = qualType(
+      allOf(builtinType(),
+            anyOf(WarnOnInts ? isBuiltinInt() : unless(anything()),
+                  WarnOnFloats ? isBuiltinFloat() : unless(anything()),
+                  WarnOnChars ? isBuiltinChar() : unless(anything()))));
+
+  if (!WarnOnInts && !WarnOnFloats && !WarnOnChars)
+    return;
+
+  Finder->addMatcher(
+      varDecl(hasType(PlatformSpecificFundamentalType)).bind("var_decl"), this);
+
+  Finder->addMatcher(
+      functionDecl(returns(PlatformSpecificFundamentalType)).bind("func_decl"),
+      this);
+
+  Finder->addMatcher(
+      parmVarDecl(hasType(PlatformSpecificFundamentalType)).bind("param_decl"),
+      this);
+
+  Finder->addMatcher(
+      fieldDecl(hasType(PlatformSpecificFundamentalType)).bind("field_decl"),
+      this);
+
+  Finder->addMatcher(
+      typedefDecl(hasUnderlyingType(PlatformSpecificFundamentalType))
+          .bind("typedef_decl"),
+      this);
+
+  Finder->addMatcher(typeAliasDecl(hasType(PlatformSpecificFundamentalType))
+                         .bind("alias_decl"),
+                     this);
+}
+
+void AvoidPlatformSpecificFundamentalTypesCheck::check(
+    const MatchFinder::MatchResult &Result) {
+  SourceLocation Loc;
+  QualType QT;
+  SourceRange TypeRange;
+
+  auto SetTypeRange = [&TypeRange](auto Decl) {
+    if (Decl->getTypeSourceInfo())
+      TypeRange = Decl->getTypeSourceInfo()->getTypeLoc().getSourceRange();
+  };
+
+  if (const auto *VD = Result.Nodes.getNodeAs<VarDecl>("var_decl")) {
+    Loc = VD->getLocation();
+    QT = VD->getType();
+    SetTypeRange(VD);
+  } else if (const auto *FD =
+                 Result.Nodes.getNodeAs<FunctionDecl>("func_decl")) {
+    Loc = FD->getLocation();
+    QT = FD->getReturnType();
+    SetTypeRange(FD);
+  } else if (const auto *PD =
+                 Result.Nodes.getNodeAs<ParmVarDecl>("param_decl")) {
+    Loc = PD->getLocation();
+    QT = PD->getType();
+    SetTypeRange(PD);
+  } else if (const auto *FD = Result.Nodes.getNodeAs<FieldDecl>("field_decl")) {
+    Loc = FD->getLocation();
+    QT = FD->getType();
+    SetTypeRange(FD);
+  } else if (const auto *TD =
+                 Result.Nodes.getNodeAs<TypedefDecl>("typedef_decl")) {
+    Loc = TD->getLocation();
+    QT = TD->getUnderlyingType();
+    SetTypeRange(TD);
+  } else if (const auto *AD =
+                 Result.Nodes.getNodeAs<TypeAliasDecl>("alias_decl")) {
+    Loc = AD->getLocation();
+    QT = AD->getUnderlyingType();
+    SetTypeRange(AD);
+  } else {
+    return;
+  }
+
+  const std::string TypeName = QT.getAsString();
+
+  const auto *BT = QT->getAs<BuiltinType>();
+
+  if (BT->isFloatingPoint()) {
+    const std::string Replacement = getFloatReplacement(BT, *Result.Context);
+    if (!Replacement.empty()) {
+      auto Diag =
+          diag(Loc, "avoid using platform-dependent floating point type '%0'; "
+                    "consider using '%1' instead")
+          << TypeName << Replacement;
+
+      if (TypeRange.isValid())
+        Diag << FixItHint::CreateReplacement(TypeRange, Replacement);
+
+      if (auto IncludeFixit = IncludeInserter.createIncludeInsertion(
+              Result.SourceManager->getFileID(Loc), "<stdfloat>")) {
+        Diag << *IncludeFixit;
+      }
+    } else {
+      diag(Loc, "avoid using platform-dependent floating point type '%0'; "
+                "consider using a typedef or fixed-width type instead")
+          << TypeName;
+    }
+  } else if (isCharType(BT)) {
+    diag(Loc, "avoid using platform-dependent character type '%0'; "
+              "consider using char8_t for text or std::byte for bytes")
+        << TypeName;
+  } else {
+    diag(Loc, "avoid using platform-dependent fundamental integer type '%0'; "
+              "consider using a typedef or fixed-width type instead")
+        << TypeName;
+  }
+}
+
+} // namespace clang::tidy::portability

clang-tools-extra/clang-tidy/portability/AvoidPlatformSpecificFundamentalTypesCheck.h

@@ -0,0 +1,50 @@
+//==-- AvoidPlatformSpecificFundamentalTypesCheck.h - clang-tidy -*- C++ -*-==//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//==------------------------------------------------------------------------==//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_PORTABILITY_AVOIDPLATFORMSPECIFICFUNDAMENTALTYPESCHECK_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_PORTABILITY_AVOIDPLATFORMSPECIFICFUNDAMENTALTYPESCHECK_H
+
+#include "../ClangTidyCheck.h"
+#include "../utils/IncludeInserter.h"
+
+namespace clang::tidy::portability {
+
+/// Find fundamental platform-dependent types and recommend using typedefs or
+/// fixed-width types.
+///
+/// Detects fundamental types (int, short, long, long long, char, float, etc)
+/// and warns against their use due to platform-dependent behavior.
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/portability/avoid-platform-specific-fundamental-types.html
+class AvoidPlatformSpecificFundamentalTypesCheck : public ClangTidyCheck {
+public:
+  AvoidPlatformSpecificFundamentalTypesCheck(StringRef Name,
+                                             ClangTidyContext *Context);
+  void registerPPCallbacks(const SourceManager &SM, Preprocessor *PP,
+                           Preprocessor *ModuleExpanderPP) override;
+  void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+  void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+  void storeOptions(ClangTidyOptions::OptionMap &Opts) override;
+  bool isLanguageVersionSupported(const LangOptions &LangOpts) const override {
+    return LangOpts.CPlusPlus11;
+  }
+  std::optional<TraversalKind> getCheckTraversalKind() const override {
+    return TK_IgnoreUnlessSpelledInSource;
+  }
+
+private:
+  const bool WarnOnFloats;
+  const bool WarnOnInts;
+  const bool WarnOnChars;
+  utils::IncludeInserter IncludeInserter;
+};
+
+} // namespace clang::tidy::portability
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_PORTABILITY_AVOIDPLATFORMSPECIFICFUNDAMENTALTYPESCHECK_H

clang-tools-extra/clang-tidy/portability/CMakeLists.txt

@@ -5,6 +5,7 @@ set(LLVM_LINK_COMPONENTS
   )
 
 add_clang_library(clangTidyPortabilityModule STATIC
+  AvoidPlatformSpecificFundamentalTypesCheck.cpp
   AvoidPragmaOnceCheck.cpp
   PortabilityTidyModule.cpp
   RestrictSystemIncludesCheck.cpp

clang-tools-extra/clang-tidy/portability/PortabilityTidyModule.cpp

@@ -9,6 +9,7 @@
 #include "../ClangTidy.h"
 #include "../ClangTidyModule.h"
 #include "../ClangTidyModuleRegistry.h"
+#include "AvoidPlatformSpecificFundamentalTypesCheck.h"
 #include "AvoidPragmaOnceCheck.h"
 #include "RestrictSystemIncludesCheck.h"
 #include "SIMDIntrinsicsCheck.h"
@@ -21,6 +22,8 @@ namespace portability {
 class PortabilityModule : public ClangTidyModule {
 public:
   void addCheckFactories(ClangTidyCheckFactories &CheckFactories) override {
+    CheckFactories.registerCheck<AvoidPlatformSpecificFundamentalTypesCheck>(
+        "portability-avoid-platform-specific-fundamental-types");
     CheckFactories.registerCheck<AvoidPragmaOnceCheck>(
         "portability-avoid-pragma-once");
     CheckFactories.registerCheck<RestrictSystemIncludesCheck>(

clang-tools-extra/docs/ReleaseNotes.rst

@@ -148,6 +148,13 @@ New checks
   Finds uses of ``std::lock_guard`` and suggests replacing them with C++17's
   alternative ``std::scoped_lock``.
 
+- New :doc:`portability-avoid-platform-specific-fundamental-types
+  <clang-tidy/checks/portability/avoid-platform-specific-fundamental-types>` 
+  check.
+
+  Finds fundamental types (e.g. `int`, `float`) and recommends using typedefs 
+  or fixed-width types instead to improve portability across different platforms.
+
 - New :doc:`portability-avoid-pragma-once
   <clang-tidy/checks/portability/avoid-pragma-once>` check.
 

clang-tools-extra/docs/clang-tidy/checks/list.rst

@@ -353,6 +353,7 @@ Clang-Tidy Checks
    :doc:`performance-type-promotion-in-math-fn <performance/type-promotion-in-math-fn>`, "Yes"
    :doc:`performance-unnecessary-copy-initialization <performance/unnecessary-copy-initialization>`, "Yes"
    :doc:`performance-unnecessary-value-param <performance/unnecessary-value-param>`, "Yes"
+   :doc:`portability-avoid-platform-specific-fundamental-types <portability/avoid-platform-specific-fundamental-types>`,
    :doc:`portability-avoid-pragma-once <portability/avoid-pragma-once>`,
    :doc:`portability-restrict-system-includes <portability/restrict-system-includes>`, "Yes"
    :doc:`portability-simd-intrinsics <portability/simd-intrinsics>`,