Revert "[libc] Add erase function to blockstore" (#98669)

Reverts #97641

Fails under sanitizers

Author: michaelrj-google

libc/src/__support/blockstore.h

@@ -9,11 +9,9 @@
 #ifndef LLVM_LIBC_SRC___SUPPORT_BLOCKSTORE_H
 #define LLVM_LIBC_SRC___SUPPORT_BLOCKSTORE_H
 
-#include "src/__support/CPP/array.h"
-#include "src/__support/CPP/new.h"
-#include "src/__support/CPP/type_traits.h"
-#include "src/__support/libc_assert.h"
 #include "src/__support/macros/config.h"
+#include <src/__support/CPP/new.h>
+#include <src/__support/libc_assert.h>
 
 #include <stddef.h>
 #include <stdint.h>
@@ -100,16 +98,6 @@ class BlockStore {
       return *reinterpret_cast<T *>(block->data + sizeof(T) * true_index);
     }
 
-    LIBC_INLINE Iterator operator+(int i) {
-      LIBC_ASSERT(i >= 0 &&
-                  "BlockStore iterators only support incrementation.");
-      auto other = *this;
-      for (int j = 0; j < i; ++j)
-        ++other;
-
-      return other;
-    }
-
     LIBC_INLINE bool operator==(const Iterator &rhs) const {
       return block == rhs.block && index == rhs.index;
     }
@@ -188,45 +176,6 @@ class BlockStore {
     else
       return Iterator(current, fill_count);
   }
-
-  // Removes the element at pos, then moves all the objects after back by one to
-  // fill the hole. It's assumed that pos is a valid iterator to somewhere in
-  // this block_store.
-  LIBC_INLINE void erase(Iterator pos) {
-    const Iterator last_item = Iterator(current, fill_count);
-    if (pos == last_item) {
-      pop_back();
-      return;
-    }
-
-    if constexpr (REVERSE_ORDER) {
-      // REVERSE: Iterate from begin to pos
-      const Iterator range_end = pos;
-      Iterator cur = begin();
-      T prev_val = *cur;
-      ++cur;
-      T cur_val = *cur;
-
-      for (; cur != range_end; ++cur) {
-        cur_val = *cur;
-        *cur = prev_val;
-        prev_val = cur_val;
-      }
-      // We will always need to move at least one item (since we know that pos
-      // isn't the last item due to the check above).
-      *cur = prev_val;
-    } else {
-      // FORWARD: Iterate from pos to end
-      const Iterator range_end = end();
-      Iterator cur = pos;
-      Iterator prev = cur;
-      ++cur;
-
-      for (; cur != range_end; prev = cur, ++cur)
-        *prev = *cur;
-    }
-    pop_back();
-  }
 };
 
 template <typename T, size_t BLOCK_SIZE, bool REVERSE_ORDER>

libc/test/src/__support/blockstore_test.cpp

@@ -64,99 +64,6 @@ class LlvmLibcBlockStoreTest : public LIBC_NAMESPACE::testing::Test {
     }
     block_store.destroy(&block_store);
   }
-
-  template <bool REVERSE> void erase_test() {
-    using LIBC_NAMESPACE::BlockStore;
-    BlockStore<int, 2, REVERSE> block_store;
-    int i;
-
-    constexpr int ARR_SIZE = 6;
-
-    ASSERT_TRUE(block_store.empty());
-    for (int i = 0; i < ARR_SIZE; i++) {
-      ASSERT_TRUE(block_store.push_back(i + 1));
-    }
-
-    // block_store state should be {1,2,3,4,5,6}
-
-    block_store.erase(block_store.begin());
-
-    // FORWARD: block_store state should be {2,3,4,5,6}
-    // REVERSE: block_store state should be {1,2,3,4,5}
-
-    auto iter = block_store.begin();
-    for (i = 0; iter != block_store.end(); ++i, ++iter) {
-      if (!REVERSE) {
-        ASSERT_EQ(*iter, i + 2);
-      } else {
-        ASSERT_EQ(*iter, (ARR_SIZE - 1) - i);
-      }
-    }
-
-    // Assert that there were the correct number of elements
-    ASSERT_EQ(i, ARR_SIZE - 1);
-
-    block_store.erase(block_store.end());
-
-    // BOTH: block_store state should be {2,3,4,5}
-
-    iter = block_store.begin();
-    for (i = 0; iter != block_store.end(); ++i, ++iter) {
-      if (!REVERSE) {
-        ASSERT_EQ(*iter, i + 2);
-      } else {
-        ASSERT_EQ(*iter, (ARR_SIZE - 1) - i);
-      }
-    }
-
-    ASSERT_EQ(i, ARR_SIZE - 2);
-
-    block_store.erase(block_store.begin() + 1);
-
-    // FORWARD: block_store state should be {2,4,5}
-    // REVERSE: block_store state should be {2,3,5}
-
-    const int FORWARD_RESULTS[] = {2, 4, 5};
-    const int REVERSE_RESULTS[] = {2, 3, 5};
-
-    iter = block_store.begin();
-    for (i = 0; iter != block_store.end(); ++i, ++iter) {
-      if (!REVERSE) {
-        ASSERT_EQ(*iter, FORWARD_RESULTS[i]);
-      } else {
-        ASSERT_EQ(*iter, REVERSE_RESULTS[ARR_SIZE - 4 - i]); // reversed
-      }
-    }
-
-    ASSERT_EQ(i, ARR_SIZE - 3);
-
-    block_store.erase(block_store.begin() + 1);
-    // BOTH: block_store state should be {2,5}
-
-    iter = block_store.begin();
-    if (!REVERSE) {
-      ASSERT_EQ(*iter, 2);
-      ASSERT_EQ(*(iter + 1), 5);
-    } else {
-      ASSERT_EQ(*iter, 5);
-      ASSERT_EQ(*(iter + 1), 2);
-    }
-
-    block_store.erase(block_store.begin());
-    // FORWARD: block_store state should be {5}
-    // REVERSE: block_store state should be {2}
-    iter = block_store.begin();
-    if (!REVERSE) {
-      ASSERT_EQ(*iter, 5);
-    } else {
-      ASSERT_EQ(*iter, 2);
-    }
-
-    block_store.erase(block_store.begin());
-    // BOTH: block_store state should be {}
-
-    block_store.destroy(&block_store);
-  }
 };
 
 TEST_F(LlvmLibcBlockStoreTest, PopulateAndIterate4) {
@@ -193,8 +100,3 @@ TEST_F(LlvmLibcBlockStoreTest, Empty) {
   empty_test<false>();
   empty_test<true>();
 }
-
-TEST_F(LlvmLibcBlockStoreTest, Erase) {
-  erase_test<false>();
-  erase_test<true>();
-}