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