1 //===- llvm/ADT/SmallVector.cpp - 'Normally small' vectors ----------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file implements the SmallVector class. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "llvm/ADT/SmallVector.h" 15 using namespace llvm; 16 17 // Check that no bytes are wasted and everything is well-aligned. 18 namespace { 19 struct Struct16B { 20 alignas(16) void *X; 21 }; 22 struct Struct32B { 23 alignas(32) void *X; 24 }; 25 } 26 static_assert(sizeof(SmallVector<void *, 0>) == 27 sizeof(unsigned) * 2 + sizeof(void *), 28 "wasted space in SmallVector size 0"); 29 static_assert(alignof(SmallVector<Struct16B, 0>) >= alignof(Struct16B), 30 "wrong alignment for 16-byte aligned T"); 31 static_assert(alignof(SmallVector<Struct32B, 0>) >= alignof(Struct32B), 32 "wrong alignment for 32-byte aligned T"); 33 static_assert(sizeof(SmallVector<Struct16B, 0>) >= alignof(Struct16B), 34 "missing padding for 16-byte aligned T"); 35 static_assert(sizeof(SmallVector<Struct32B, 0>) >= alignof(Struct32B), 36 "missing padding for 32-byte aligned T"); 37 static_assert(sizeof(SmallVector<void *, 1>) == 38 sizeof(unsigned) * 2 + sizeof(void *) * 2, 39 "wasted space in SmallVector size 1"); 40 41 /// grow_pod - This is an implementation of the grow() method which only works 42 /// on POD-like datatypes and is out of line to reduce code duplication. 43 void SmallVectorBase::grow_pod(void *FirstEl, size_t MinCapacity, 44 size_t TSize) { 45 // Ensure we can fit the new capacity in 32 bits. 46 if (MinCapacity > UINT32_MAX) 47 report_bad_alloc_error("SmallVector capacity overflow during allocation"); 48 49 size_t NewCapacity = 2 * capacity() + 1; // Always grow. 50 NewCapacity = 51 std::min(std::max(NewCapacity, MinCapacity), size_t(UINT32_MAX)); 52 53 void *NewElts; 54 if (BeginX == FirstEl) { 55 NewElts = safe_malloc(NewCapacity * TSize); 56 57 // Copy the elements over. No need to run dtors on PODs. 58 memcpy(NewElts, this->BeginX, size() * TSize); 59 } else { 60 // If this wasn't grown from the inline copy, grow the allocated space. 61 NewElts = safe_realloc(this->BeginX, NewCapacity * TSize); 62 } 63 64 this->BeginX = NewElts; 65 this->Capacity = NewCapacity; 66 } 67
