lib/Support/SmallVector.cpp

   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.
  18 static_assert(sizeof(SmallVector<void *, 1>) == sizeof(void *) * 4,
  19               "wasted space in SmallVector size 1; missing EBO?");
  20
  21 /// grow_pod - This is an implementation of the grow() method which only works
  22 /// on POD-like datatypes and is out of line to reduce code duplication.
  23 void SmallVectorBase::grow_pod(void *FirstEl, size_t MinSizeInBytes,
  24                                size_t TSize) {
  25   size_t CurSizeBytes = size_in_bytes();
  26   size_t NewCapacityInBytes = 2 * capacity_in_bytes() + TSize; // Always grow.
  27   if (NewCapacityInBytes < MinSizeInBytes)
  28     NewCapacityInBytes = MinSizeInBytes;
  29
  30   void *NewElts;
  31   if (BeginX == FirstEl) {
  32     NewElts = safe_malloc(NewCapacityInBytes);
  33
  34     // Copy the elements over.  No need to run dtors on PODs.
  35     memcpy(NewElts, this->BeginX, CurSizeBytes);
  36   } else {
  37     // If this wasn't grown from the inline copy, grow the allocated space.
  38     NewElts = safe_realloc(this->BeginX, NewCapacityInBytes);
  39   }
  40
  41   this->EndX = (char*)NewElts+CurSizeBytes;
  42   this->BeginX = NewElts;
  43   this->CapacityX = (char*)this->BeginX + NewCapacityInBytes;
  44 }