clang/lib/Analysis/FlowSensitive/Formula.cpp

   1 //===- Formula.cpp ----------------------------------------------*- 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 #include "clang/Analysis/FlowSensitive/Formula.h"
  10 #include "clang/Basic/LLVM.h"
  11 #include "llvm/ADT/STLExtras.h"
  12 #include "llvm/ADT/StringRef.h"
  13 #include "llvm/Support/Allocator.h"
  14 #include "llvm/Support/ErrorHandling.h"
  15 #include <cassert>
  16 #include <type_traits>
  17
  18 namespace clang::dataflow {
  19
  20 const Formula &Formula::create(llvm::BumpPtrAllocator &Alloc, Kind K,
  21                                ArrayRef<const Formula *> Operands,
  22                                unsigned Value) {
  23   assert(Operands.size() == numOperands(K));
  24   if (Value != 0) // Currently, formulas have values or operands, not both.
  25     assert(numOperands(K) == 0);
  26   void *Mem = Alloc.Allocate(sizeof(Formula) +
  27                                  Operands.size() * sizeof(Operands.front()),
  28                              alignof(Formula));
  29   Formula *Result = new (Mem) Formula();
  30   Result->FormulaKind = K;
  31   Result->Value = Value;
  32   // Operands are stored as `const Formula *`s after the formula itself.
  33   // We don't need to construct an object as pointers are trivial types.
  34   // Formula is alignas(const Formula *), so alignment is satisfied.
  35   llvm::copy(Operands, reinterpret_cast<const Formula **>(Result + 1));
  36   return *Result;
  37 }
  38
  39 static llvm::StringLiteral sigil(Formula::Kind K) {
  40   switch (K) {
  41   case Formula::AtomRef:
  42   case Formula::Literal:
  43     return "";
  44   case Formula::Not:
  45     return "!";
  46   case Formula::And:
  47     return " & ";
  48   case Formula::Or:
  49     return " | ";
  50   case Formula::Implies:
  51     return " => ";
  52   case Formula::Equal:
  53     return " = ";
  54   }
  55   llvm_unreachable("unhandled formula kind");
  56 }
  57
  58 void Formula::print(llvm::raw_ostream &OS, const AtomNames *Names) const {
  59   if (Names && kind() == AtomRef)
  60     if (auto It = Names->find(getAtom()); It != Names->end()) {
  61       OS << It->second;
  62       return;
  63     }
  64
  65   switch (numOperands(kind())) {
  66   case 0:
  67     switch (kind()) {
  68     case AtomRef:
  69       OS << getAtom();
  70       break;
  71     case Literal:
  72       OS << (literal() ? "true" : "false");
  73       break;
  74     default:
  75       llvm_unreachable("unhandled formula kind");
  76     }
  77     break;
  78   case 1:
  79     OS << sigil(kind());
  80     operands()[0]->print(OS, Names);
  81     break;
  82   case 2:
  83     OS << '(';
  84     operands()[0]->print(OS, Names);
  85     OS << sigil(kind());
  86     operands()[1]->print(OS, Names);
  87     OS << ')';
  88     break;
  89   default:
  90     llvm_unreachable("unhandled formula arity");
  91   }
  92 }
  93
  94 } // namespace clang::dataflow