[llvm] f489e86 - Remove Waymarking.h as it is unused
Aaron Ballman via llvm-commits
llvm-commits at lists.llvm.org
Fri Jan 28 11:20:27 PST 2022
Author: Aaron Ballman
Date: 2022-01-28T14:20:06-05:00
New Revision: f489e86a24d38015197597beb88ff357cd7681b9
URL: https://github.com/llvm/llvm-project/commit/f489e86a24d38015197597beb88ff357cd7681b9
DIFF: https://github.com/llvm/llvm-project/commit/f489e86a24d38015197597beb88ff357cd7681b9.diff
LOG: Remove Waymarking.h as it is unused
This file was added in https://reviews.llvm.org/D74415. There was no
justification as to why it was added, and after about a year of being
in-tree, it's still unused, so this removes it.
Added:
Modified:
llvm/unittests/ADT/CMakeLists.txt
Removed:
llvm/include/llvm/ADT/Waymarking.h
llvm/unittests/ADT/WaymarkingTest.cpp
################################################################################
diff --git a/llvm/include/llvm/ADT/Waymarking.h b/llvm/include/llvm/ADT/Waymarking.h
deleted file mode 100644
index 2efbc6f05495..000000000000
--- a/llvm/include/llvm/ADT/Waymarking.h
+++ /dev/null
@@ -1,322 +0,0 @@
-//===- Waymarking.h - Array waymarking algorithm ----------------*- C++ -*-===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-//
-// Utility to backtrace an array's head, from a pointer into it. For the
-// backtrace to work, we use "Waymarks", which are special tags embedded into
-// the array's elements.
-//
-// A Tag of n-bits (in size) is composed as follows:
-//
-// bits: | n-1 | n-2 ... 0 |
-// .---------.------------------------------------.
-// |Stop Mask|(2^(n-1))-ary numeric system - digit|
-// '---------'------------------------------------'
-//
-// Backtracing is done as follows:
-// Walk back (starting from a given pointer to an element into the array), until
-// a tag with a "Stop Mask" is reached. Then start calculating the "Offset" from
-// the array's head, by picking up digits along the way, until another stop is
-// reached. The "Offset" is then subtracted from the current pointer, and the
-// result is the array's head.
-// A special case - if we first encounter a Tag with a Stop and a zero digit,
-// then this is already the head.
-//
-// For example:
-// In case of 2 bits:
-//
-// Tags:
-// x0 - binary digit 0
-// x1 - binary digit 1
-// 1x - stop and calculate (s)
-//
-// Array:
-// .---.---.---.---.---.---.---.---.---.---.---.---.---.---.---.---.
-// head -> |s0 |s1 | 0 |s1 | 0 | 0 |s1 | 1 | 1 |s1 | 0 | 1 | 0 |s1 | 0 | 1 |
-// '---'---'---'---'---'---'---'---'---'---'---'---'---'---'---'---'
-// |-1 |-2 |-4 |-7 |-10 |-14
-// <_ | | | | | |
-// <_____ | | | | |
-// <_____________ | | | |
-// <_________________________ | | |
-// <_____________________________________ | |
-// <_____________________________________________________ |
-//
-//
-// In case of 3 bits:
-//
-// Tags:
-// x00 - quaternary digit 0
-// x01 - quaternary digit 1
-// x10 - quaternary digit 2
-// x11 - quaternary digit 3
-// 1xy - stop and calculate (s)
-//
-// Array:
-// .---.---.---.---.---.---.---.---.---.---.---.---.---.---.---.---.
-// head -> |s0 |s1 |s2 |s3 | 0 |s1 | 2 |s1 | 0 |s2 | 2 |s2 | 0 |s3 | 2 |s3 |
-// '---'---'---'---'---'---'---'---'---'---'---'---'---'---'---'---'
-// |-1 |-2 |-3 |-4 |-6 |-8 |-10 |-12 |-14 |-16
-// <_ | | | | | | | | | |
-// <_____ | | | | | | | | |
-// <_________ | | | | | | | |
-// <_____________ | | | | | | |
-// <_____________________ | | | | | |
-// <_____________________________ | | | | |
-// <_____________________________________ | | | |
-// <_____________________________________________ | | |
-// <_____________________________________________________ | |
-// <_____________________________________________________________ |
-//
-//
-// The API introduce 2 functions:
-// 1. fillWaymarks
-// 2. followWaymarks
-//
-// Example:
-// int N = 10;
-// int M = 5;
-// int **A = new int *[N + M]; // Define the array.
-// for (int I = 0; I < N + M; ++I)
-// A[I] = new int(I);
-//
-// fillWaymarks(A, A + N); // Set the waymarks for the first N elements
-// // of the array.
-// // Note that it must be done AFTER we fill
-// // the array's elements.
-//
-// ... // Elements which are not in the range
-// // [A, A+N) will not be marked, and we won't
-// // be able to call followWaymarks on them.
-//
-// ... // Elements which will be changed after the
-// // call to fillWaymarks, will have to be
-// // retagged.
-//
-// fillWaymarks(A + N, A + N + M, N); // Set the waymarks of the remaining M
-// // elements.
-// ...
-// int **It = A + N + 1;
-// int **B = followWaymarks(It); // Find the head of the array containing It.
-// assert(B == A);
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef LLVM_ADT_WAYMARKING_H
-#define LLVM_ADT_WAYMARKING_H
-
-#include "llvm/ADT/STLExtras.h"
-#include "llvm/Support/PointerLikeTypeTraits.h"
-
-namespace llvm {
-
-namespace detail {
-
-template <unsigned NumBits> struct WaymarkingTraits {
- enum : unsigned {
- // The number of bits of a Waymarking Tag.
- NUM_BITS = NumBits,
-
- // A Tag is composed from a Mark and a Stop mask.
- MARK_SIZE = NUM_BITS - 1,
- STOP_MASK = (1 << MARK_SIZE),
- MARK_MASK = (STOP_MASK - 1),
- TAG_MASK = (MARK_MASK | STOP_MASK),
-
- // The number of pre-computed tags (for fast fill).
- NUM_STATIC_TAGS = 32
- };
-
-private:
- // Add a new tag, calculated from Count and Stop, to the Vals pack, while
- // continuing recursively to decrease Len down to 0.
- template <unsigned Len, bool Stop, unsigned Count, uint8_t... Vals>
- struct AddTag;
-
- // Delegate to the specialized AddTag according to the need of a Stop mask.
- template <unsigned Len, unsigned Count, uint8_t... Vals> struct GenTag {
- typedef
- typename AddTag<Len, (Count <= MARK_MASK), Count, Vals...>::Xdata Xdata;
- };
-
- // Start adding tags while calculating the next Count, which is actually the
- // number of already calculated tags (equivalent to the position in the
- // array).
- template <unsigned Len, uint8_t... Vals> struct GenOffset {
- typedef typename GenTag<Len, sizeof...(Vals), Vals...>::Xdata Xdata;
- };
-
- // Add the tag and remove it from Count.
- template <unsigned Len, unsigned Count, uint8_t... Vals>
- struct AddTag<Len, false, Count, Vals...> {
- typedef typename GenTag<Len - 1, (Count >> MARK_SIZE), Vals...,
- Count & MARK_MASK>::Xdata Xdata;
- };
-
- // We have reached the end of this Count, so start with a new Count.
- template <unsigned Len, unsigned Count, uint8_t... Vals>
- struct AddTag<Len, true, Count, Vals...> {
- typedef typename GenOffset<Len - 1, Vals...,
- (Count & MARK_MASK) | STOP_MASK>::Xdata Xdata;
- };
-
- template <unsigned Count, uint8_t... Vals> struct TagsData {
- // The remaining number for calculating the next tag, following the last one
- // in Values.
- static const unsigned Remain = Count;
-
- // The array of ordered pre-computed Tags.
- static const uint8_t Values[sizeof...(Vals)];
- };
-
- // Specialize the case when Len equals 0, as the recursion stop condition.
- template <unsigned Count, uint8_t... Vals>
- struct AddTag<0, false, Count, Vals...> {
- typedef TagsData<Count, Vals...> Xdata;
- };
-
- template <unsigned Count, uint8_t... Vals>
- struct AddTag<0, true, Count, Vals...> {
- typedef TagsData<Count, Vals...> Xdata;
- };
-
-public:
- typedef typename GenOffset<NUM_STATIC_TAGS>::Xdata Tags;
-};
-
-template <unsigned NumBits>
-template <unsigned Count, uint8_t... Vals>
-const uint8_t WaymarkingTraits<NumBits>::TagsData<
- Count, Vals...>::Values[sizeof...(Vals)] = {Vals...};
-
-} // end namespace detail
-
-/// This class is responsible for tagging (and retrieving the tag of) a given
-/// element of type T.
-template <class T, class WTraits = detail::WaymarkingTraits<
- PointerLikeTypeTraits<T>::NumLowBitsAvailable>>
-struct Waymarker {
- using Traits = WTraits;
- static void setWaymark(T &N, unsigned Tag) { N.setWaymark(Tag); }
- static unsigned getWaymark(const T &N) { return N.getWaymark(); }
-};
-
-template <class T, class WTraits> struct Waymarker<T *, WTraits> {
- using Traits = WTraits;
- static void setWaymark(T *&N, unsigned Tag) {
- reinterpret_cast<uintptr_t &>(N) |= static_cast<uintptr_t>(Tag);
- }
- static unsigned getWaymark(const T *N) {
- return static_cast<unsigned>(reinterpret_cast<uintptr_t>(N)) &
- Traits::TAG_MASK;
- }
-};
-
-/// Sets up the waymarking algorithm's tags for a given range [Begin, End).
-///
-/// \param Begin The beginning of the range to mark with tags (inclusive).
-/// \param End The ending of the range to mark with tags (exclusive).
-/// \param Offset The position in the supposed tags array from which to start
-/// marking the given range.
-template <class TIter, class Marker = Waymarker<
- typename std::iterator_traits<TIter>::value_type>>
-void fillWaymarks(TIter Begin, TIter End, size_t Offset = 0) {
- if (Begin == End)
- return;
-
- size_t Count = Marker::Traits::Tags::Remain;
- if (Offset <= Marker::Traits::NUM_STATIC_TAGS) {
- // Start by filling the pre-calculated tags, starting from the given offset.
- while (Offset != Marker::Traits::NUM_STATIC_TAGS) {
- Marker::setWaymark(*Begin, Marker::Traits::Tags::Values[Offset]);
-
- ++Offset;
- ++Begin;
-
- if (Begin == End)
- return;
- }
- } else {
- // The given offset is larger than the number of pre-computed tags, so we
- // must do it the hard way.
- // Calculate the next remaining Count, as if we have filled the tags up to
- // the given offset.
- size_t Off = Marker::Traits::NUM_STATIC_TAGS;
- do {
- ++Off;
-
- // If the count can fit into the tag, then the counting must stop.
- if (Count <= Marker::Traits::MARK_MASK) {
- Count = Off;
- } else
- Count >>= Marker::Traits::MARK_SIZE;
- } while (Off != Offset);
- }
-
- // By now, we have the matching remaining Count for the current offset.
- do {
- ++Offset;
-
- unsigned Tag = Count & Marker::Traits::MARK_MASK;
-
- // If the count can fit into the tag, then the counting must stop.
- if (Count <= Marker::Traits::MARK_MASK) {
- Tag |= Marker::Traits::STOP_MASK;
- Count = Offset;
- } else
- Count >>= Marker::Traits::MARK_SIZE;
-
- Marker::setWaymark(*Begin, Tag);
- ++Begin;
- } while (Begin != End);
-}
-
-/// Sets up the waymarking algorithm's tags for a given range.
-///
-/// \param Range The range to mark with tags.
-/// \param Offset The position in the supposed tags array from which to start
-/// marking the given range.
-template <typename R, class Marker = Waymarker<typename std::remove_reference<
- decltype(*std::begin(std::declval<R &>()))>::type>>
-void fillWaymarks(R &&Range, size_t Offset = 0) {
- return fillWaymarks<decltype(std::begin(std::declval<R &>())), Marker>(
- adl_begin(Range), adl_end(Range), Offset);
-}
-
-/// Retrieves the element marked with tag of only STOP_MASK, by following the
-/// waymarks. This is the first element in a range passed to a previous call to
-/// \c fillWaymarks with \c Offset 0.
-///
-/// For the trivial usage of calling \c fillWaymarks(Array), and \I is an
-/// iterator inside \c Array, this function retrieves the head of \c Array, by
-/// following the waymarks.
-///
-/// \param I The iterator into an array which was marked by the waymarking tags
-/// (by a previous call to \c fillWaymarks).
-template <class TIter, class Marker = Waymarker<
- typename std::iterator_traits<TIter>::value_type>>
-TIter followWaymarks(TIter I) {
- unsigned Tag;
- do
- Tag = Marker::getWaymark(*I--);
- while (!(Tag & Marker::Traits::STOP_MASK));
-
- // Special case for the first Use.
- if (Tag != Marker::Traits::STOP_MASK) {
- ptr
diff _t Offset = Tag & Marker::Traits::MARK_MASK;
- while (!((Tag = Marker::getWaymark(*I)) & Marker::Traits::STOP_MASK)) {
- Offset = (Offset << Marker::Traits::MARK_SIZE) + Tag;
- --I;
- }
- I -= Offset;
- }
- return ++I;
-}
-
-} // end namespace llvm
-
-#endif // LLVM_ADT_WAYMARKING_H
diff --git a/llvm/unittests/ADT/CMakeLists.txt b/llvm/unittests/ADT/CMakeLists.txt
index f98624f60f9c..3b3d7c5483c2 100644
--- a/llvm/unittests/ADT/CMakeLists.txt
+++ b/llvm/unittests/ADT/CMakeLists.txt
@@ -79,7 +79,6 @@ add_llvm_unittest(ADTTests
TwineTest.cpp
TypeSwitchTest.cpp
TypeTraitsTest.cpp
- WaymarkingTest.cpp
)
target_link_libraries(ADTTests PRIVATE LLVMTestingSupport)
diff --git a/llvm/unittests/ADT/WaymarkingTest.cpp b/llvm/unittests/ADT/WaymarkingTest.cpp
deleted file mode 100644
index 0a6b66e8d21c..000000000000
--- a/llvm/unittests/ADT/WaymarkingTest.cpp
+++ /dev/null
@@ -1,142 +0,0 @@
-//===- llvm/unittest/IR/WaymarkTest.cpp - Waymarking unit tests -----------===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-#include "llvm/ADT/Waymarking.h"
-#include "gtest/gtest.h"
-
-using namespace llvm;
-
-static const int N = 100;
-
-// Get the Waymarking Tag of the pointer.
-static int tag(int *P) {
- return static_cast<int>(reinterpret_cast<uintptr_t>(P) &
- uintptr_t(alignof(int *) - 1));
-}
-
-// Get the actual pointer, by stripping the Waymarking Tag.
-static int *ref(int *P) {
- return reinterpret_cast<int *>(reinterpret_cast<uintptr_t>(P) &
- ~uintptr_t(alignof(int *) - 1));
-}
-
-static int **createArray(int Len) {
- int **A = new int *[Len];
- for (int I = 0; I < Len; ++I)
- A[I] = new int(I);
- return A;
-}
-
-static void freeArray(int **A, int Len) {
- for (int I = 0; I < Len; ++I)
- delete ref(A[I]);
- delete[] A;
-}
-
-// Verify the values stored in the array are as expected, and did not change due
-// to fillWaymarks.
-static void verifyArrayValues(int **A, int Begin, int End) {
- for (int I = Begin; I < End; ++I)
- EXPECT_EQ(I, *ref(A[I]));
-}
-
-static void verifyArrayValues(int **A, int Len) {
- verifyArrayValues(A, 0, Len);
-}
-
-// Verify that we can follow the waymarks to the array's head from each element
-// of the array.
-static void verifyFollowWaymarks(int **A, int Len) {
- for (int I = 0; I < Len; ++I) {
- int **P = followWaymarks(A + I);
- EXPECT_EQ(A, P);
- }
-}
-
-namespace {
-
-// Test filling and following the waymarks of a single array.
-TEST(WaymarkingTest, SingleHead) {
- const int N2 = 2 * N;
- int **volatile A = createArray(N2);
-
- // Fill the first half of the array with waymarks.
- fillWaymarks(A, A + N, 0);
- verifyArrayValues(A, N2);
-
- verifyFollowWaymarks(A, N);
-
- // Fill the rest of the waymarks (continuing from where we stopped).
- fillWaymarks(A + N, A + N2, N);
- verifyArrayValues(A, N2);
-
- verifyFollowWaymarks(A, N);
-
- freeArray(A, N2);
-}
-
-// Test filling and following the waymarks of an array split into several
-//
diff erent sections of waymarks (treated just like separate arrays).
-TEST(WaymarkingTest, MultiHead) {
- const int N2 = 2 * N;
- const int N3 = 3 * N;
- int **volatile A = createArray(N3);
-
- // Separate the array into 3 sections of waymarks.
- fillWaymarks(A, A + N, 0);
- fillWaymarks(A + N, A + N2, 0);
- fillWaymarks(A + N2, A + N3, 0);
- verifyArrayValues(A, N3);
-
- verifyFollowWaymarks(A, N);
- verifyFollowWaymarks(A + N, N2 - N);
- verifyFollowWaymarks(A + N2, N3 - N2);
-
- freeArray(A, N3);
-}
-
-// Test reseting (value and tag of) elements inside an array of waymarks.
-TEST(WaymarkingTest, Reset) {
- int **volatile A = createArray(N);
-
- fillWaymarks(A, A + N, 0);
- verifyArrayValues(A, N);
-
- const int N2 = N / 2;
- const int N3 = N / 3;
- const int N4 = N / 4;
-
- // Reset specific elements and check that the tag remains the same.
- int T2 = tag(A[N2]);
- delete ref(A[N2]);
- A[N2] = new int(N2);
- fillWaymarks(A + N2, A + N2 + 1, N2);
- verifyArrayValues(A, N2, N2 + 1);
- EXPECT_EQ(T2, tag(A[N2]));
-
- int T3 = tag(A[N3]);
- delete ref(A[N3]);
- A[N3] = new int(N3);
- fillWaymarks(A + N3, A + N3 + 1, N3);
- verifyArrayValues(A, N3, N3 + 1);
- EXPECT_EQ(T3, tag(A[N3]));
-
- int T4 = tag(A[N4]);
- delete ref(A[N4]);
- A[N4] = new int(N4);
- fillWaymarks(A + N4, A + N4 + 1, N4);
- verifyArrayValues(A, N4, N4 + 1);
- EXPECT_EQ(T4, tag(A[N4]));
-
- verifyArrayValues(A, N);
- verifyFollowWaymarks(A, N);
-
- freeArray(A, N);
-}
-
-} // end anonymous namespace
More information about the llvm-commits
mailing list