[clang-tools-extra] [clang-tidy] Add portability-avoid-platform-specific-fundamental-types (PR #146970)

[Baranov Victor via cfe-commits]

================
@@ -0,0 +1,260 @@
+//===--- 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/ASTMatchers/ASTMatchFinder.h"
+#include "clang/ASTMatchers/ASTMatchers.h"
+#include "clang/Basic/TargetInfo.h"
+
+using namespace clang::ast_matchers;
+
+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());
+}
+
+std::string AvoidPlatformSpecificFundamentalTypesCheck::getFloatReplacement(
+    const BuiltinType *BT, ASTContext &Context) const {
+  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) {
+  // Build the list of type strings to match
+  std::vector<std::string> TypeStrings;
+
+  // Add integer types if the option is enabled
+  if (WarnOnInts) {
+    TypeStrings.insert(TypeStrings.end(), {"short",
+                                           "short int",
+                                           "signed short",
+                                           "signed short int",
+                                           "unsigned short",
+                                           "unsigned short int",
+                                           "int",
+                                           "signed",
+                                           "signed int",
+                                           "unsigned",
+                                           "unsigned int",
+                                           "long",
+                                           "long int",
+                                           "signed long",
+                                           "signed long int",
+                                           "unsigned long",
+                                           "unsigned long int",
+                                           "long long",
+                                           "long long int",
+                                           "signed long long",
+                                           "signed long long int",
+                                           "unsigned long long",
+                                           "unsigned long long int"});
+  }
+
+  // Add float types if the option is enabled
+  if (WarnOnFloats) {
+    TypeStrings.insert(TypeStrings.end(),
+                       {"half", "__bf16", "float", "double", "long double"});
+  }
+
+  // Add char types if the option is enabled
+  if (WarnOnChars) {
+    TypeStrings.insert(TypeStrings.end(),
+                       {"char", "signed char", "unsigned char"});
+  }
+
+  // If no types are enabled, return early
+  if (TypeStrings.empty()) {
+    return;
+  }
----------------
vbvictor wrote:

```suggestion
  if (TypeStrings.empty())
    return;
```
https://llvm.org/docs/CodingStandards.html#don-t-use-braces-on-simple-single-statement-bodies-of-if-else-loop-statements. There are other places too, please correct.

You could enable https://clang.llvm.org/docs/ClangFormatStyleOptions.html#removebracesllvm in your clang-format file.

https://github.com/llvm/llvm-project/pull/146970