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//===--- DurationRewriter.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 "DurationRewriter.h"
#include "clang/Tooling/FixIt.h"
#include "llvm/ADT/IndexedMap.h"
using namespace clang::ast_matchers;
namespace clang {
namespace tidy {
namespace abseil {
struct DurationScale2IndexFunctor {
using argument_type = DurationScale;
unsigned operator()(DurationScale Scale) const {
return static_cast<unsigned>(Scale);
}
};
/// 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;
}
/// Given a `Scale` return the inverse functions for it.
static const std::pair<llvm::StringRef, llvm::StringRef> &
getInverseForScale(DurationScale Scale) {
static const llvm::IndexedMap<std::pair<llvm::StringRef, llvm::StringRef>,
DurationScale2IndexFunctor>
InverseMap = []() {
// TODO: Revisit the immediately invoked lamba technique when
// IndexedMap gets an initializer list constructor.
llvm::IndexedMap<std::pair<llvm::StringRef, llvm::StringRef>,
DurationScale2IndexFunctor>
InverseMap;
InverseMap.resize(6);
InverseMap[DurationScale::Hours] =
std::make_pair("::absl::ToDoubleHours", "::absl::ToInt64Hours");
InverseMap[DurationScale::Minutes] =
std::make_pair("::absl::ToDoubleMinutes", "::absl::ToInt64Minutes");
InverseMap[DurationScale::Seconds] =
std::make_pair("::absl::ToDoubleSeconds", "::absl::ToInt64Seconds");
InverseMap[DurationScale::Milliseconds] = std::make_pair(
"::absl::ToDoubleMilliseconds", "::absl::ToInt64Milliseconds");
InverseMap[DurationScale::Microseconds] = std::make_pair(
"::absl::ToDoubleMicroseconds", "::absl::ToInt64Microseconds");
InverseMap[DurationScale::Nanoseconds] = std::make_pair(
"::absl::ToDoubleNanoseconds", "::absl::ToInt64Nanoseconds");
return InverseMap;
}();
return InverseMap[Scale];
}
/// If `Node` is a call to the inverse of `Scale`, return that inverse's
/// argument, otherwise None.
static llvm::Optional<std::string>
rewriteInverseDurationCall(const MatchFinder::MatchResult &Result,
DurationScale Scale, const Expr &Node) {
const std::pair<llvm::StringRef, llvm::StringRef> &InverseFunctions =
getInverseForScale(Scale);
if (const auto *MaybeCallArg = selectFirst<const Expr>(
"e",
match(callExpr(callee(functionDecl(hasAnyName(
InverseFunctions.first, InverseFunctions.second))),
hasArgument(0, expr().bind("e"))),
Node, *Result.Context))) {
return tooling::fixit::getText(*MaybeCallArg, *Result.Context).str();
}
return llvm::None;
}
/// Returns the factory function name for a given `Scale`.
llvm::StringRef getFactoryForScale(DurationScale Scale) {
switch (Scale) {
case DurationScale::Hours:
return "absl::Hours";
case DurationScale::Minutes:
return "absl::Minutes";
case DurationScale::Seconds:
return "absl::Seconds";
case DurationScale::Milliseconds:
return "absl::Milliseconds";
case DurationScale::Microseconds:
return "absl::Microseconds";
case DurationScale::Nanoseconds:
return "absl::Nanoseconds";
}
llvm_unreachable("unknown scaling factor");
}
/// Returns `true` if `Node` is a value which evaluates to a literal `0`.
bool IsLiteralZero(const MatchFinder::MatchResult &Result, const Expr &Node) {
return selectFirst<const clang::Expr>(
"val",
match(expr(ignoringImpCasts(anyOf(integerLiteral(equals(0)),
floatLiteral(equals(0.0)))))
.bind("val"),
Node, *Result.Context)) != nullptr;
}
llvm::Optional<std::string>
stripFloatCast(const ast_matchers::MatchFinder::MatchResult &Result,
const Expr &Node) {
if (const Expr *MaybeCastArg = selectFirst<const Expr>(
"cast_arg",
match(expr(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"))))),
Node, *Result.Context)))
return tooling::fixit::getText(*MaybeCastArg, *Result.Context).str();
return llvm::None;
}
llvm::Optional<std::string>
stripFloatLiteralFraction(const MatchFinder::MatchResult &Result,
const Expr &Node) {
if (const auto *LitFloat = llvm::dyn_cast<FloatingLiteral>(&Node))
// Attempt to simplify a `Duration` factory call with a literal argument.
if (llvm::Optional<llvm::APSInt> IntValue = truncateIfIntegral(*LitFloat))
return IntValue->toString(/*radix=*/10);
return llvm::None;
}
std::string simplifyDurationFactoryArg(const MatchFinder::MatchResult &Result,
const Expr &Node) {
// Check for an explicit cast to `float` or `double`.
if (llvm::Optional<std::string> MaybeArg = stripFloatCast(Result, Node))
return *MaybeArg;
// Check for floats without fractional components.
if (llvm::Optional<std::string> MaybeArg =
stripFloatLiteralFraction(Result, Node))
return *MaybeArg;
// We couldn't simplify any further, so return the argument text.
return tooling::fixit::getText(Node, *Result.Context).str();
}
llvm::Optional<DurationScale> getScaleForInverse(llvm::StringRef Name) {
static const llvm::StringMap<DurationScale> ScaleMap(
{{"ToDoubleHours", DurationScale::Hours},
{"ToInt64Hours", DurationScale::Hours},
{"ToDoubleMinutes", DurationScale::Minutes},
{"ToInt64Minutes", DurationScale::Minutes},
{"ToDoubleSeconds", DurationScale::Seconds},
{"ToInt64Seconds", DurationScale::Seconds},
{"ToDoubleMilliseconds", DurationScale::Milliseconds},
{"ToInt64Milliseconds", DurationScale::Milliseconds},
{"ToDoubleMicroseconds", DurationScale::Microseconds},
{"ToInt64Microseconds", DurationScale::Microseconds},
{"ToDoubleNanoseconds", DurationScale::Nanoseconds},
{"ToInt64Nanoseconds", DurationScale::Nanoseconds}});
auto ScaleIter = ScaleMap.find(std::string(Name));
if (ScaleIter == ScaleMap.end())
return llvm::None;
return ScaleIter->second;
}
std::string rewriteExprFromNumberToDuration(
const ast_matchers::MatchFinder::MatchResult &Result, DurationScale Scale,
const Expr *Node) {
const Expr &RootNode = *Node->IgnoreParenImpCasts();
// First check to see if we can undo a complimentary function call.
if (llvm::Optional<std::string> MaybeRewrite =
rewriteInverseDurationCall(Result, Scale, RootNode))
return *MaybeRewrite;
if (IsLiteralZero(Result, RootNode))
return std::string("absl::ZeroDuration()");
return (llvm::Twine(getFactoryForScale(Scale)) + "(" +
simplifyDurationFactoryArg(Result, RootNode) + ")")
.str();
}
} // namespace abseil
} // namespace tidy
} // namespace clang
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