clang/lib/Basic/BuiltinTargetFeatures.h

   1 //===-- CodeGenFunction.h - Target features for builtin ---------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This is the internal required target features for builtin.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #ifndef LLVM_CLANG_LIB_BASIC_BUILTINTARGETFEATURES_H
  14 #define LLVM_CLANG_LIB_BASIC_BUILTINTARGETFEATURES_H
  15 #include "llvm/ADT/StringMap.h"
  16 #include "llvm/ADT/StringRef.h"
  17
  18 using llvm::StringRef;
  19
  20 namespace clang {
  21 namespace Builtin {
  22 /// TargetFeatures - This class is used to check whether the builtin function
  23 /// has the required tagert specific features. It is able to support the
  24 /// combination of ','(and), '|'(or), and '()'. By default, the priority of
  25 /// ',' is higher than that of '|' .
  26 /// E.g:
  27 /// A,B|C means the builtin function requires both A and B, or C.
  28 /// If we want the builtin function requires both A and B, or both A and C,
  29 /// there are two ways: A,B|A,C or A,(B|C).
  30 /// The FeaturesList should not contain spaces, and brackets must appear in
  31 /// pairs.
  32 class TargetFeatures {
  33   struct FeatureListStatus {
  34     bool HasFeatures;
  35     StringRef CurFeaturesList;
  36   };
  37
  38   const llvm::StringMap<bool> &CallerFeatureMap;
  39
  40   FeatureListStatus getAndFeatures(StringRef FeatureList) {
  41     int InParentheses = 0;
  42     bool HasFeatures = true;
  43     size_t SubexpressionStart = 0;
  44     for (size_t i = 0, e = FeatureList.size(); i < e; ++i) {
  45       char CurrentToken = FeatureList[i];
  46       switch (CurrentToken) {
  47       default:
  48         break;
  49       case '(':
  50         if (InParentheses == 0)
  51           SubexpressionStart = i + 1;
  52         ++InParentheses;
  53         break;
  54       case ')':
  55         --InParentheses;
  56         assert(InParentheses >= 0 && "Parentheses are not in pair");
  57         [[fallthrough]];
  58       case '|':
  59       case ',':
  60         if (InParentheses == 0) {
  61           if (HasFeatures && i != SubexpressionStart) {
  62             StringRef F = FeatureList.slice(SubexpressionStart, i);
  63             HasFeatures = CurrentToken == ')' ? hasRequiredFeatures(F)
  64                                               : CallerFeatureMap.lookup(F);
  65           }
  66           SubexpressionStart = i + 1;
  67           if (CurrentToken == '|') {
  68             return {HasFeatures, FeatureList.substr(SubexpressionStart)};
  69           }
  70         }
  71         break;
  72       }
  73     }
  74     assert(InParentheses == 0 && "Parentheses are not in pair");
  75     if (HasFeatures && SubexpressionStart != FeatureList.size())
  76       HasFeatures =
  77           CallerFeatureMap.lookup(FeatureList.substr(SubexpressionStart));
  78     return {HasFeatures, StringRef()};
  79   }
  80
  81 public:
  82   bool hasRequiredFeatures(StringRef FeatureList) {
  83     FeatureListStatus FS = {false, FeatureList};
  84     while (!FS.HasFeatures && !FS.CurFeaturesList.empty())
  85       FS = getAndFeatures(FS.CurFeaturesList);
  86     return FS.HasFeatures;
  87   }
  88
  89   TargetFeatures(const llvm::StringMap<bool> &CallerFeatureMap)
  90       : CallerFeatureMap(CallerFeatureMap) {}
  91 };
  92
  93 } // namespace Builtin
  94 } // namespace clang
  95 #endif /* CLANG_LIB_BASIC_BUILTINTARGETFEATURES_H */