[llvm] 5cb4c37 - Revert "ADT: SmallVector size/capacity use word-size integers when elements are small"
Andrew Browne via llvm-commits
llvm-commits at lists.llvm.org
Fri Apr 24 19:25:17 PDT 2020
Author: Andrew Browne
Date: 2020-04-24T19:24:46-07:00
New Revision: 5cb4c3776a34d48e43d9118921d2191aee0e3d21
URL: https://github.com/llvm/llvm-project/commit/5cb4c3776a34d48e43d9118921d2191aee0e3d21
DIFF: https://github.com/llvm/llvm-project/commit/5cb4c3776a34d48e43d9118921d2191aee0e3d21.diff
LOG: Revert "ADT: SmallVector size/capacity use word-size integers when elements are small"
This reverts commit b5f0eae1dc3c09c020cdf9d07238dec9acdacf5f.
clang-cmake-armv7-quick/llvm/llvm/lib/Support/SmallVector.cpp:81:22:
error: duplicate explicit instantiation of 'SmallVectorBase<unsigned int>'
Added:
Modified:
llvm/include/llvm/ADT/SmallVector.h
llvm/lib/Support/SmallVector.cpp
Removed:
################################################################################
diff --git a/llvm/include/llvm/ADT/SmallVector.h b/llvm/include/llvm/ADT/SmallVector.h
index d02d7a65b23e..12a58761955b 100644
--- a/llvm/include/llvm/ADT/SmallVector.h
+++ b/llvm/include/llvm/ADT/SmallVector.h
@@ -16,10 +16,10 @@
#include "llvm/ADT/iterator_range.h"
#include "llvm/Support/AlignOf.h"
#include "llvm/Support/Compiler.h"
-#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/MemAlloc.h"
#include "llvm/Support/type_traits.h"
+#include "llvm/Support/ErrorHandling.h"
#include <algorithm>
#include <cassert>
#include <cstddef>
@@ -27,7 +27,6 @@
#include <cstring>
#include <initializer_list>
#include <iterator>
-#include <limits>
#include <memory>
#include <new>
#include <type_traits>
@@ -35,23 +34,11 @@
namespace llvm {
-/// This is all the stuff common to all SmallVectors.
-///
-/// The template parameter specifies the type which should be used to hold the
-/// Size and Capacity of the SmallVector, so it can be adjusted.
-/// Using 32 bit size is desirable to shink the size of the SmallVector.
-/// Using 64 bit size is desirable for cases like SmallVector<char>, where a
-/// 32 bit size would limit the vector to ~4GB. SmallVectors are used for
-/// buffering bitcode output - which can exceed 4GB.
-template <class Size_T> class SmallVectorBase {
+/// This is all the non-templated stuff common to all SmallVectors.
+class SmallVectorBase {
protected:
void *BeginX;
- Size_T Size = 0, Capacity;
-
- /// The maximum value of the Size_T used.
- static constexpr size_t SizeTypeMax() {
- return std::numeric_limits<Size_T>::max();
- }
+ unsigned Size = 0, Capacity;
SmallVectorBase() = delete;
SmallVectorBase(void *FirstEl, size_t TotalCapacity)
@@ -83,13 +70,9 @@ template <class Size_T> class SmallVectorBase {
}
};
-template <class T>
-using SmallVectorSizeType =
- typename std::conditional<sizeof(T) < 4, uintptr_t, uint32_t>::type;
-
/// Figure out the offset of the first element.
template <class T, typename = void> struct SmallVectorAlignmentAndSize {
- AlignedCharArrayUnion<SmallVectorBase<SmallVectorSizeType<T>>> Base;
+ AlignedCharArrayUnion<SmallVectorBase> Base;
AlignedCharArrayUnion<T> FirstEl;
};
@@ -97,10 +80,7 @@ template <class T, typename = void> struct SmallVectorAlignmentAndSize {
/// the type T is a POD. The extra dummy template argument is used by ArrayRef
/// to avoid unnecessarily requiring T to be complete.
template <typename T, typename = void>
-class SmallVectorTemplateCommon
- : public SmallVectorBase<SmallVectorSizeType<T>> {
- using Base = SmallVectorBase<SmallVectorSizeType<T>>;
-
+class SmallVectorTemplateCommon : public SmallVectorBase {
/// Find the address of the first element. For this pointer math to be valid
/// with small-size of 0 for T with lots of alignment, it's important that
/// SmallVectorStorage is properly-aligned even for small-size of 0.
@@ -112,20 +92,21 @@ class SmallVectorTemplateCommon
// Space after 'FirstEl' is clobbered, do not add any instance vars after it.
protected:
- SmallVectorTemplateCommon(size_t Size) : Base(getFirstEl(), Size) {}
+ SmallVectorTemplateCommon(size_t Size)
+ : SmallVectorBase(getFirstEl(), Size) {}
void grow_pod(size_t MinCapacity, size_t TSize) {
- Base::grow_pod(getFirstEl(), MinCapacity, TSize);
+ SmallVectorBase::grow_pod(getFirstEl(), MinCapacity, TSize);
}
/// Return true if this is a smallvector which has not had dynamic
/// memory allocated for it.
- bool isSmall() const { return this->BeginX == getFirstEl(); }
+ bool isSmall() const { return BeginX == getFirstEl(); }
/// Put this vector in a state of being small.
void resetToSmall() {
- this->BeginX = getFirstEl();
- this->Size = this->Capacity = 0; // FIXME: Setting Capacity to 0 is suspect.
+ BeginX = getFirstEl();
+ Size = Capacity = 0; // FIXME: Setting Capacity to 0 is suspect.
}
public:
@@ -143,10 +124,6 @@ class SmallVectorTemplateCommon
using pointer = T *;
using const_pointer = const T *;
- using Base::capacity;
- using Base::empty;
- using Base::size;
-
// forward iterator creation methods.
iterator begin() { return (iterator)this->BeginX; }
const_iterator begin() const { return (const_iterator)this->BeginX; }
@@ -160,9 +137,7 @@ class SmallVectorTemplateCommon
const_reverse_iterator rend() const { return const_reverse_iterator(begin());}
size_type size_in_bytes() const { return size() * sizeof(T); }
- size_type max_size() const {
- return std::min(this->SizeTypeMax(), size_type(-1) / sizeof(T));
- }
+ size_type max_size() const { return size_type(-1) / sizeof(T); }
size_t capacity_in_bytes() const { return capacity() * sizeof(T); }
@@ -257,21 +232,18 @@ class SmallVectorTemplateBase : public SmallVectorTemplateCommon<T> {
// Define this out-of-line to dissuade the C++ compiler from inlining it.
template <typename T, bool TriviallyCopyable>
void SmallVectorTemplateBase<T, TriviallyCopyable>::grow(size_t MinSize) {
- // Ensure we can fit the new capacity.
- // This is only going to be applicable when the capacity is 32 bit.
- if (MinSize > this->SizeTypeMax())
+ if (MinSize > UINT32_MAX)
report_bad_alloc_error("SmallVector capacity overflow during allocation");
// Ensure we can meet the guarantee of space for at least one more element.
// The above check alone will not catch the case where grow is called with a
// default MinCapacity of 0, but the current capacity cannot be increased.
- // This is only going to be applicable when the capacity is 32 bit.
- if (this->capacity() == this->SizeTypeMax())
+ if (this->capacity() == size_t(UINT32_MAX))
report_bad_alloc_error("SmallVector capacity unable to grow");
// Always grow, even from zero.
size_t NewCapacity = size_t(NextPowerOf2(this->capacity() + 2));
- NewCapacity = std::min(std::max(NewCapacity, MinSize), this->SizeTypeMax());
+ NewCapacity = std::min(std::max(NewCapacity, MinSize), size_t(UINT32_MAX));
T *NewElts = static_cast<T*>(llvm::safe_malloc(NewCapacity*sizeof(T)));
// Move the elements over.
diff --git a/llvm/lib/Support/SmallVector.cpp b/llvm/lib/Support/SmallVector.cpp
index e267bdeadfb9..9ece0c5a3b62 100644
--- a/llvm/lib/Support/SmallVector.cpp
+++ b/llvm/lib/Support/SmallVector.cpp
@@ -37,30 +37,24 @@ static_assert(sizeof(SmallVector<void *, 1>) ==
sizeof(unsigned) * 2 + sizeof(void *) * 2,
"wasted space in SmallVector size 1");
-static_assert(sizeof(SmallVector<char, 0>) ==
- sizeof(void *) * 2 + sizeof(void *),
- "1 byte elements have word-sized type for size and capacity");
-
-// Note: Moving this function into the header may cause performance regression.
-template <class Size_T>
-void SmallVectorBase<Size_T>::grow_pod(void *FirstEl, size_t MinCapacity,
- size_t TSize) {
- // Ensure we can fit the new capacity.
- // This is only going to be applicable when the capacity is 32 bit.
- if (MinCapacity > SizeTypeMax())
+/// 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.
+/// This function will report a fatal error if it cannot increase capacity.
+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");
// Ensure we can meet the guarantee of space for at least one more element.
// The above check alone will not catch the case where grow is called with a
// default MinCapacity of 0, but the current capacity cannot be increased.
- // This is only going to be applicable when the capacity is 32 bit.
- if (capacity() == SizeTypeMax())
+ if (capacity() == size_t(UINT32_MAX))
report_bad_alloc_error("SmallVector capacity unable to grow");
- // In theory 2*capacity can overflow if the capacity is 64 bit, but the
- // original capacity would never be large enough for this to be a problem.
size_t NewCapacity = 2 * capacity() + 1; // Always grow.
- NewCapacity = std::min(std::max(NewCapacity, MinCapacity), SizeTypeMax());
+ NewCapacity =
+ std::min(std::max(NewCapacity, MinCapacity), size_t(UINT32_MAX));
void *NewElts;
if (BeginX == FirstEl) {
@@ -76,6 +70,3 @@ void SmallVectorBase<Size_T>::grow_pod(void *FirstEl, size_t MinCapacity,
this->BeginX = NewElts;
this->Capacity = NewCapacity;
}
-
-template class llvm::SmallVectorBase<uint32_t>;
-template class llvm::SmallVectorBase<uintptr_t>;
More information about the llvm-commits
mailing list