1//===- llvm/ADT/SmallVector.cpp - 'Normally small' vectors ----------------===//
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 the SmallVector class.
10//
11//===----------------------------------------------------------------------===//
12
13#include "llvm/ADT/SmallVector.h"
14using namespace llvm;
15
16// Check that no bytes are wasted and everything is well-aligned.
17namespace {
18struct Struct16B {
19  alignas(16) void *X;
20};
21struct Struct32B {
22  alignas(32) void *X;
23};
24}
25static_assert(sizeof(SmallVector<void *, 0>) ==
26                  sizeof(unsigned) * 2 + sizeof(void *),
27              "wasted space in SmallVector size 0");
28static_assert(alignof(SmallVector<Struct16B, 0>) >= alignof(Struct16B),
29              "wrong alignment for 16-byte aligned T");
30static_assert(alignof(SmallVector<Struct32B, 0>) >= alignof(Struct32B),
31              "wrong alignment for 32-byte aligned T");
32static_assert(sizeof(SmallVector<Struct16B, 0>) >= alignof(Struct16B),
33              "missing padding for 16-byte aligned T");
34static_assert(sizeof(SmallVector<Struct32B, 0>) >= alignof(Struct32B),
35              "missing padding for 32-byte aligned T");
36static_assert(sizeof(SmallVector<void *, 1>) ==
37                  sizeof(unsigned) * 2 + sizeof(void *) * 2,
38              "wasted space in SmallVector size 1");
39
40/// grow_pod - This is an implementation of the grow() method which only works
41/// on POD-like datatypes and is out of line to reduce code duplication.
42void SmallVectorBase::grow_pod(void *FirstEl, size_t MinCapacity,
43                               size_t TSize) {
44  // Ensure we can fit the new capacity in 32 bits.
45  if (MinCapacity > UINT32_MAX)
46    report_bad_alloc_error("SmallVector capacity overflow during allocation");
47
48  size_t NewCapacity = 2 * capacity() + 1; // Always grow.
49  NewCapacity =
50      std::min(std::max(NewCapacity, MinCapacity), size_t(UINT32_MAX));
51
52  void *NewElts;
53  if (BeginX == FirstEl) {
54    NewElts = safe_malloc(NewCapacity * TSize);
55
56    // Copy the elements over.  No need to run dtors on PODs.
57    memcpy(NewElts, this->BeginX, size() * TSize);
58  } else {
59    // If this wasn't grown from the inline copy, grow the allocated space.
60    NewElts = safe_realloc(this->BeginX, NewCapacity * TSize);
61  }
62
63  this->BeginX = NewElts;
64  this->Capacity = NewCapacity;
65}
66