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llvm-mirror/lib/Support/SmallVector.cpp
Duncan P. N. Exon Smith c5c96d69c8 ADT: Shrink size of SmallVector by 8B on 64-bit platforms
Representing size and capacity directly as unsigned and calculate
`end()` using `begin() + size()`.

This limits the maximum size/capacity of a vector to UINT32_MAX.

https://reviews.llvm.org/D48518

llvm-svn: 337504
2018-07-19 22:29:47 +00:00

48 lines
1.7 KiB
C++

//===- llvm/ADT/SmallVector.cpp - 'Normally small' vectors ----------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the SmallVector class.
//
//===----------------------------------------------------------------------===//
#include "llvm/ADT/SmallVector.h"
using namespace llvm;
// Check that no bytes are wasted.
static_assert(sizeof(SmallVector<void *, 1>) ==
sizeof(unsigned) * 2 + sizeof(void *) * 2,
"wasted space in SmallVector size 1; missing EBO?");
/// grow_pod - This is an implementation of the grow() method which only works
/// on POD-like datatypes and is out of line to reduce code duplication.
void SmallVectorBase::grow_pod(void *FirstEl, size_t MinCapacity,
size_t TSize) {
// Ensure we can fit the new capacity in 32 bits.
if (MinCapacity > UINT32_MAX)
report_bad_alloc_error("SmallVector capacity overflow during allocation");
size_t NewCapacity = 2 * capacity() + 1; // Always grow.
NewCapacity =
std::min(std::max(NewCapacity, MinCapacity), size_t(UINT32_MAX));
void *NewElts;
if (BeginX == FirstEl) {
NewElts = safe_malloc(NewCapacity * TSize);
// Copy the elements over. No need to run dtors on PODs.
memcpy(NewElts, this->BeginX, size() * TSize);
} else {
// If this wasn't grown from the inline copy, grow the allocated space.
NewElts = safe_realloc(this->BeginX, NewCapacity * TSize);
}
this->BeginX = NewElts;
this->Capacity = NewCapacity;
}