1 files changed, 106 insertions, 0 deletions
diff --git a/clang-tools-extra/clang-tidy/abseil/DurationFactoryFloatCheck.cpp b/clang-tools-extra/clang-tidy/abseil/DurationFactoryFloatCheck.cpp
new file mode 100644
index 00000000000..80ecf8a812e
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/abseil/DurationFactoryFloatCheck.cpp
@@ -0,0 +1,106 @@
+//===--- DurationFactoryFloatCheck.cpp - clang-tidy -----------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "DurationFactoryFloatCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/Tooling/FixIt.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace abseil {
+
+// Returns an integer if the fractional part of a `FloatingLiteral` is `0`.
+static llvm::Optional<llvm::APSInt>
+truncateIfIntegral(const FloatingLiteral &FloatLiteral) {
+  double Value = FloatLiteral.getValueAsApproximateDouble();
+  if (std::fmod(Value, 1) == 0) {
+    if (Value >= static_cast<double>(1u << 31))
+      return llvm::None;
+
+    return llvm::APSInt::get(static_cast<int64_t>(Value));
+  }
+  return llvm::None;
+}
+
+// Returns `true` if `Range` is inside a macro definition.
+static bool InsideMacroDefinition(const MatchFinder::MatchResult &Result,
+                                  SourceRange Range) {
+  return !clang::Lexer::makeFileCharRange(
+              clang::CharSourceRange::getCharRange(Range),
+              *Result.SourceManager, Result.Context->getLangOpts())
+              .isValid();
+}
+
+void DurationFactoryFloatCheck::registerMatchers(MatchFinder *Finder) {
+  Finder->addMatcher(
+      callExpr(
+          callee(functionDecl(hasAnyName(
+              "absl::Nanoseconds", "absl::Microseconds", "absl::Milliseconds",
+              "absl::Seconds", "absl::Minutes", "absl::Hours"))),
+          hasArgument(0,
+                      anyOf(cxxStaticCastExpr(
+                                hasDestinationType(realFloatingPointType()),
+                                hasSourceExpression(expr().bind("cast_arg"))),
+                            cStyleCastExpr(
+                                hasDestinationType(realFloatingPointType()),
+                                hasSourceExpression(expr().bind("cast_arg"))),
+                            cxxFunctionalCastExpr(
+                                hasDestinationType(realFloatingPointType()),
+                                hasSourceExpression(expr().bind("cast_arg"))),
+                            floatLiteral().bind("float_literal"))))
+          .bind("call"),
+      this);
+}
+
+void DurationFactoryFloatCheck::check(const MatchFinder::MatchResult &Result) {
+  const auto *MatchedCall = Result.Nodes.getNodeAs<CallExpr>("call");
+
+  // Don't try and replace things inside of macro definitions.
+  if (InsideMacroDefinition(Result, MatchedCall->getSourceRange()))
+    return;
+
+  const Expr *Arg = MatchedCall->getArg(0)->IgnoreImpCasts();
+  // Arguments which are macros are ignored.
+  if (Arg->getBeginLoc().isMacroID())
+    return;
+
+  // Check for casts to `float` or `double`.
+  if (const auto *MaybeCastArg = Result.Nodes.getNodeAs<Expr>("cast_arg")) {
+    diag(MatchedCall->getBeginLoc(),
+         (llvm::Twine("use the integer version of absl::") +
+          MatchedCall->getDirectCallee()->getName())
+             .str())
+        << FixItHint::CreateReplacement(
+               Arg->getSourceRange(),
+               tooling::fixit::getText(*MaybeCastArg, *Result.Context));
+    return;
+  }
+
+  // Check for floats without fractional components.
+  if (const auto *LitFloat =
+          Result.Nodes.getNodeAs<FloatingLiteral>("float_literal")) {
+    // Attempt to simplify a `Duration` factory call with a literal argument.
+    if (llvm::Optional<llvm::APSInt> IntValue = truncateIfIntegral(*LitFloat)) {
+      diag(MatchedCall->getBeginLoc(),
+           (llvm::Twine("use the integer version of absl::") +
+            MatchedCall->getDirectCallee()->getName())
+               .str())
+          << FixItHint::CreateReplacement(LitFloat->getSourceRange(),
+                                          IntValue->toString(/*radix=*/10));
+      return;
+    }
+  }
+}
+
+} // namespace abseil
+} // namespace tidy
+} // namespace clang