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llvm-mirror/include/llvm/MC/SubtargetFeature.h
Matthias Braun 70dad586fc SubtargetFeature: Cleanup; NFC
- Fix doxygen comments
- Remove duplicated comments
- Remove section comments (which became wrong over time)
- Use more `const` and references but less `auto`

llvm-svn: 295687
2017-02-21 01:27:29 +00:00

131 lines
4.3 KiB
C++

//===- llvm/MC/SubtargetFeature.h - CPU characteristics ---------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
/// \file Defines and manages user or tool specified CPU characteristics.
/// The intent is to be able to package specific features that should or should
/// not be used on a specific target processor. A tool, such as llc, could, as
/// as example, gather chip info from the command line, a long with features
/// that should be used on that chip.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_MC_SUBTARGETFEATURE_H
#define LLVM_MC_SUBTARGETFEATURE_H
#include "llvm/ADT/StringRef.h"
#include <bitset>
#include <initializer_list>
#include <string>
#include <vector>
namespace llvm {
template <typename T> class ArrayRef;
class raw_ostream;
class Triple;
const unsigned MAX_SUBTARGET_FEATURES = 192;
/// Container class for subtarget features.
/// This is convenient because std::bitset does not have a constructor
/// with an initializer list of set bits.
class FeatureBitset : public std::bitset<MAX_SUBTARGET_FEATURES> {
public:
// Cannot inherit constructors because it's not supported by VC++..
FeatureBitset() = default;
FeatureBitset(const bitset<MAX_SUBTARGET_FEATURES>& B) : bitset(B) {}
FeatureBitset(std::initializer_list<unsigned> Init) {
for (auto I : Init)
set(I);
}
};
//===----------------------------------------------------------------------===//
/// Used to provide key value pairs for feature and CPU bit flags.
struct SubtargetFeatureKV {
const char *Key; ///< K-V key string
const char *Desc; ///< Help descriptor
FeatureBitset Value; ///< K-V integer value
FeatureBitset Implies; ///< K-V bit mask
/// Compare routine for std::lower_bound
bool operator<(StringRef S) const {
return StringRef(Key) < S;
}
/// Compare routine for std::is_sorted.
bool operator<(const SubtargetFeatureKV &Other) const {
return StringRef(Key) < StringRef(Other.Key);
}
};
//===----------------------------------------------------------------------===//
/// Used to provide key value pairs for CPU and arbitrary pointers.
struct SubtargetInfoKV {
const char *Key; ///< K-V key string
const void *Value; ///< K-V pointer value
/// Compare routine for std::lower_bound
bool operator<(StringRef S) const {
return StringRef(Key) < S;
}
};
//===----------------------------------------------------------------------===//
/// Manages the enabling and disabling of subtarget specific features.
///
/// Features are encoded as a string of the form
/// "+attr1,+attr2,-attr3,...,+attrN"
/// A comma separates each feature from the next (all lowercase.)
/// Each of the remaining features is prefixed with + or - indicating whether
/// that feature should be enabled or disabled contrary to the cpu
/// specification.
class SubtargetFeatures {
std::vector<std::string> Features; ///< Subtarget features as a vector
public:
explicit SubtargetFeatures(StringRef Initial = "");
/// Returns features as a string.
std::string getString() const;
/// Adds Features.
void AddFeature(StringRef String, bool Enable = true);
/// Toggles a feature and update the feature bits.
static void ToggleFeature(FeatureBitset &Bits, StringRef String,
ArrayRef<SubtargetFeatureKV> FeatureTable);
/// Applies the feature flag and update the feature bits.
static void ApplyFeatureFlag(FeatureBitset &Bits, StringRef Feature,
ArrayRef<SubtargetFeatureKV> FeatureTable);
/// Returns feature bits of a CPU.
FeatureBitset getFeatureBits(StringRef CPU,
ArrayRef<SubtargetFeatureKV> CPUTable,
ArrayRef<SubtargetFeatureKV> FeatureTable);
/// Prints feature string.
void print(raw_ostream &OS) const;
// Dumps feature info.
void dump() const;
/// Adds the default features for the specified target triple.
void getDefaultSubtargetFeatures(const Triple& Triple);
};
} // end namespace llvm
#endif // LLVM_MC_SUBTARGETFEATURE_H