LLVM  10.0.0svn
LEB128.cpp
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1 //===- LEB128.cpp - LEB128 utility functions implementation -----*- 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 file implements some utility functions for encoding SLEB128 and
10 // ULEB128 values.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "llvm/Support/LEB128.h"
15 
16 namespace llvm {
17 
18 /// Utility function to get the size of the ULEB128-encoded value.
19 unsigned getULEB128Size(uint64_t Value) {
20  unsigned Size = 0;
21  do {
22  Value >>= 7;
23  Size += sizeof(int8_t);
24  } while (Value);
25  return Size;
26 }
27 
28 /// Utility function to get the size of the SLEB128-encoded value.
29 unsigned getSLEB128Size(int64_t Value) {
30  unsigned Size = 0;
31  int Sign = Value >> (8 * sizeof(Value) - 1);
32  bool IsMore;
33 
34  do {
35  unsigned Byte = Value & 0x7f;
36  Value >>= 7;
37  IsMore = Value != Sign || ((Byte ^ Sign) & 0x40) != 0;
38  Size += sizeof(int8_t);
39  } while (IsMore);
40  return Size;
41 }
42 
43 } // namespace llvm
This class represents lattice values for constants.
Definition: AllocatorList.h:23
unsigned getULEB128Size(uint64_t Value)
Utility function to get the size of the ULEB128-encoded value.
Definition: LEB128.cpp:19
uint32_t Size
Definition: Profile.cpp:46
unsigned getSLEB128Size(int64_t Value)
Utility function to get the size of the SLEB128-encoded value.
Definition: LEB128.cpp:29
LLVM Value Representation.
Definition: Value.h:73