1 files changed, 434 insertions, 0 deletions
diff --git a/contrib/llvm-project/lldb/source/Target/Memory.cpp b/contrib/llvm-project/lldb/source/Target/Memory.cpp
new file mode 100644
index 000000000000..45786415d23b
--- /dev/null
+++ b/contrib/llvm-project/lldb/source/Target/Memory.cpp
@@ -0,0 +1,434 @@
+//===-- Memory.cpp --------------------------------------------------------===//
+//
+// 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 "lldb/Target/Memory.h"
+#include "lldb/Target/Process.h"
+#include "lldb/Utility/DataBufferHeap.h"
+#include "lldb/Utility/LLDBLog.h"
+#include "lldb/Utility/Log.h"
+#include "lldb/Utility/RangeMap.h"
+#include "lldb/Utility/State.h"
+
+#include <cinttypes>
+#include <memory>
+
+using namespace lldb;
+using namespace lldb_private;
+
+// MemoryCache constructor
+MemoryCache::MemoryCache(Process &process)
+    : m_mutex(), m_L1_cache(), m_L2_cache(), m_invalid_ranges(),
+      m_process(process),
+      m_L2_cache_line_byte_size(process.GetMemoryCacheLineSize()) {}
+
+// Destructor
+MemoryCache::~MemoryCache() = default;
+
+void MemoryCache::Clear(bool clear_invalid_ranges) {
+  std::lock_guard<std::recursive_mutex> guard(m_mutex);
+  m_L1_cache.clear();
+  m_L2_cache.clear();
+  if (clear_invalid_ranges)
+    m_invalid_ranges.Clear();
+  m_L2_cache_line_byte_size = m_process.GetMemoryCacheLineSize();
+}
+
+void MemoryCache::AddL1CacheData(lldb::addr_t addr, const void *src,
+                                 size_t src_len) {
+  AddL1CacheData(
+      addr, DataBufferSP(new DataBufferHeap(DataBufferHeap(src, src_len))));
+}
+
+void MemoryCache::AddL1CacheData(lldb::addr_t addr,
+                                 const DataBufferSP &data_buffer_sp) {
+  std::lock_guard<std::recursive_mutex> guard(m_mutex);
+  m_L1_cache[addr] = data_buffer_sp;
+}
+
+void MemoryCache::Flush(addr_t addr, size_t size) {
+  if (size == 0)
+    return;
+
+  std::lock_guard<std::recursive_mutex> guard(m_mutex);
+
+  // Erase any blocks from the L1 cache that intersect with the flush range
+  if (!m_L1_cache.empty()) {
+    AddrRange flush_range(addr, size);
+    BlockMap::iterator pos = m_L1_cache.upper_bound(addr);
+    if (pos != m_L1_cache.begin()) {
+      --pos;
+    }
+    while (pos != m_L1_cache.end()) {
+      AddrRange chunk_range(pos->first, pos->second->GetByteSize());
+      if (!chunk_range.DoesIntersect(flush_range))
+        break;
+      pos = m_L1_cache.erase(pos);
+    }
+  }
+
+  if (!m_L2_cache.empty()) {
+    const uint32_t cache_line_byte_size = m_L2_cache_line_byte_size;
+    const addr_t end_addr = (addr + size - 1);
+    const addr_t first_cache_line_addr = addr - (addr % cache_line_byte_size);
+    const addr_t last_cache_line_addr =
+        end_addr - (end_addr % cache_line_byte_size);
+    // Watch for overflow where size will cause us to go off the end of the
+    // 64 bit address space
+    uint32_t num_cache_lines;
+    if (last_cache_line_addr >= first_cache_line_addr)
+      num_cache_lines = ((last_cache_line_addr - first_cache_line_addr) /
+                         cache_line_byte_size) +
+                        1;
+    else
+      num_cache_lines =
+          (UINT64_MAX - first_cache_line_addr + 1) / cache_line_byte_size;
+
+    uint32_t cache_idx = 0;
+    for (addr_t curr_addr = first_cache_line_addr; cache_idx < num_cache_lines;
+         curr_addr += cache_line_byte_size, ++cache_idx) {
+      BlockMap::iterator pos = m_L2_cache.find(curr_addr);
+      if (pos != m_L2_cache.end())
+        m_L2_cache.erase(pos);
+    }
+  }
+}
+
+void MemoryCache::AddInvalidRange(lldb::addr_t base_addr,
+                                  lldb::addr_t byte_size) {
+  if (byte_size > 0) {
+    std::lock_guard<std::recursive_mutex> guard(m_mutex);
+    InvalidRanges::Entry range(base_addr, byte_size);
+    m_invalid_ranges.Append(range);
+    m_invalid_ranges.Sort();
+  }
+}
+
+bool MemoryCache::RemoveInvalidRange(lldb::addr_t base_addr,
+                                     lldb::addr_t byte_size) {
+  if (byte_size > 0) {
+    std::lock_guard<std::recursive_mutex> guard(m_mutex);
+    const uint32_t idx = m_invalid_ranges.FindEntryIndexThatContains(base_addr);
+    if (idx != UINT32_MAX) {
+      const InvalidRanges::Entry *entry = m_invalid_ranges.GetEntryAtIndex(idx);
+      if (entry->GetRangeBase() == base_addr &&
+          entry->GetByteSize() == byte_size)
+        return m_invalid_ranges.RemoveEntryAtIndex(idx);
+    }
+  }
+  return false;
+}
+
+lldb::DataBufferSP MemoryCache::GetL2CacheLine(lldb::addr_t line_base_addr,
+                                               Status &error) {
+  // This function assumes that the address given is aligned correctly.
+  assert((line_base_addr % m_L2_cache_line_byte_size) == 0);
+
+  std::lock_guard<std::recursive_mutex> guard(m_mutex);
+  auto pos = m_L2_cache.find(line_base_addr);
+  if (pos != m_L2_cache.end())
+    return pos->second;
+
+  auto data_buffer_heap_sp =
+      std::make_shared<DataBufferHeap>(m_L2_cache_line_byte_size, 0);
+  size_t process_bytes_read = m_process.ReadMemoryFromInferior(
+      line_base_addr, data_buffer_heap_sp->GetBytes(),
+      data_buffer_heap_sp->GetByteSize(), error);
+
+  // If we failed a read, not much we can do.
+  if (process_bytes_read == 0)
+    return lldb::DataBufferSP();
+
+  // If we didn't get a complete read, we can still cache what we did get.
+  if (process_bytes_read < m_L2_cache_line_byte_size)
+    data_buffer_heap_sp->SetByteSize(process_bytes_read);
+
+  m_L2_cache[line_base_addr] = data_buffer_heap_sp;
+  return data_buffer_heap_sp;
+}
+
+size_t MemoryCache::Read(addr_t addr, void *dst, size_t dst_len,
+                         Status &error) {
+  if (!dst || dst_len == 0)
+    return 0;
+
+  std::lock_guard<std::recursive_mutex> guard(m_mutex);
+  // FIXME: We should do a more thorough check to make sure that we're not
+  // overlapping with any invalid ranges (e.g. Read 0x100 - 0x200 but there's an
+  // invalid range 0x180 - 0x280). `FindEntryThatContains` has an implementation
+  // that takes a range, but it only checks to see if the argument is contained
+  // by an existing invalid range. It cannot check if the argument contains
+  // invalid ranges and cannot check for overlaps.
+  if (m_invalid_ranges.FindEntryThatContains(addr)) {
+    error.SetErrorStringWithFormat("memory read failed for 0x%" PRIx64, addr);
+    return 0;
+  }
+
+  // Check the L1 cache for a range that contains the entire memory read.
+  // L1 cache contains chunks of memory that are not required to be the size of
+  // an L2 cache line. We avoid trying to do partial reads from the L1 cache to
+  // simplify the implementation.
+  if (!m_L1_cache.empty()) {
+    AddrRange read_range(addr, dst_len);
+    BlockMap::iterator pos = m_L1_cache.upper_bound(addr);
+    if (pos != m_L1_cache.begin()) {
+      --pos;
+    }
+    AddrRange chunk_range(pos->first, pos->second->GetByteSize());
+    if (chunk_range.Contains(read_range)) {
+      memcpy(dst, pos->second->GetBytes() + (addr - chunk_range.GetRangeBase()),
+             dst_len);
+      return dst_len;
+    }
+  }
+
+  // If the size of the read is greater than the size of an L2 cache line, we'll
+  // just read from the inferior. If that read is successful, we'll cache what
+  // we read in the L1 cache for future use.
+  if (dst_len > m_L2_cache_line_byte_size) {
+    size_t bytes_read =
+        m_process.ReadMemoryFromInferior(addr, dst, dst_len, error);
+    if (bytes_read > 0)
+      AddL1CacheData(addr, dst, bytes_read);
+    return bytes_read;
+  }
+
+  // If the size of the read fits inside one L2 cache line, we'll try reading
+  // from the L2 cache. Note that if the range of memory we're reading sits
+  // between two contiguous cache lines, we'll touch two cache lines instead of
+  // just one.
+
+  // We're going to have all of our loads and reads be cache line aligned.
+  addr_t cache_line_offset = addr % m_L2_cache_line_byte_size;
+  addr_t cache_line_base_addr = addr - cache_line_offset;
+  DataBufferSP first_cache_line = GetL2CacheLine(cache_line_base_addr, error);
+  // If we get nothing, then the read to the inferior likely failed. Nothing to
+  // do here.
+  if (!first_cache_line)
+    return 0;
+
+  // If the cache line was not filled out completely and the offset is greater
+  // than what we have available, we can't do anything further here.
+  if (cache_line_offset >= first_cache_line->GetByteSize())
+    return 0;
+
+  uint8_t *dst_buf = (uint8_t *)dst;
+  size_t bytes_left = dst_len;
+  size_t read_size = first_cache_line->GetByteSize() - cache_line_offset;
+  if (read_size > bytes_left)
+    read_size = bytes_left;
+
+  memcpy(dst_buf + dst_len - bytes_left,
+         first_cache_line->GetBytes() + cache_line_offset, read_size);
+  bytes_left -= read_size;
+
+  // If the cache line was not filled out completely and we still have data to
+  // read, we can't do anything further.
+  if (first_cache_line->GetByteSize() < m_L2_cache_line_byte_size &&
+      bytes_left > 0)
+    return dst_len - bytes_left;
+
+  // We'll hit this scenario if our read straddles two cache lines.
+  if (bytes_left > 0) {
+    cache_line_base_addr += m_L2_cache_line_byte_size;
+
+    // FIXME: Until we are able to more thoroughly check for invalid ranges, we
+    // will have to check the second line to see if it is in an invalid range as
+    // well. See the check near the beginning of the function for more details.
+    if (m_invalid_ranges.FindEntryThatContains(cache_line_base_addr)) {
+      error.SetErrorStringWithFormat("memory read failed for 0x%" PRIx64,
+                                     cache_line_base_addr);
+      return dst_len - bytes_left;
+    }
+
+    DataBufferSP second_cache_line =
+        GetL2CacheLine(cache_line_base_addr, error);
+    if (!second_cache_line)
+      return dst_len - bytes_left;
+
+    read_size = bytes_left;
+    if (read_size > second_cache_line->GetByteSize())
+      read_size = second_cache_line->GetByteSize();
+
+    memcpy(dst_buf + dst_len - bytes_left, second_cache_line->GetBytes(),
+           read_size);
+    bytes_left -= read_size;
+
+    return dst_len - bytes_left;
+  }
+
+  return dst_len;
+}
+
+AllocatedBlock::AllocatedBlock(lldb::addr_t addr, uint32_t byte_size,
+                               uint32_t permissions, uint32_t chunk_size)
+    : m_range(addr, byte_size), m_permissions(permissions),
+      m_chunk_size(chunk_size)
+{
+  // The entire address range is free to start with.
+  m_free_blocks.Append(m_range);
+  assert(byte_size > chunk_size);
+}
+
+AllocatedBlock::~AllocatedBlock() = default;
+
+lldb::addr_t AllocatedBlock::ReserveBlock(uint32_t size) {
+  // We must return something valid for zero bytes.
+  if (size == 0)
+    size = 1;
+  Log *log = GetLog(LLDBLog::Process);
+
+  const size_t free_count = m_free_blocks.GetSize();
+  for (size_t i=0; i<free_count; ++i)
+  {
+    auto &free_block = m_free_blocks.GetEntryRef(i);
+    const lldb::addr_t range_size = free_block.GetByteSize();
+    if (range_size >= size)
+    {
+      // We found a free block that is big enough for our data. Figure out how
+      // many chunks we will need and calculate the resulting block size we
+      // will reserve.
+      addr_t addr = free_block.GetRangeBase();
+      size_t num_chunks = CalculateChunksNeededForSize(size);
+      lldb::addr_t block_size = num_chunks * m_chunk_size;
+      lldb::addr_t bytes_left = range_size - block_size;
+      if (bytes_left == 0)
+      {
+        // The newly allocated block will take all of the bytes in this
+        // available block, so we can just add it to the allocated ranges and
+        // remove the range from the free ranges.
+        m_reserved_blocks.Insert(free_block, false);
+        m_free_blocks.RemoveEntryAtIndex(i);
+      }
+      else
+      {
+        // Make the new allocated range and add it to the allocated ranges.
+        Range<lldb::addr_t, uint32_t> reserved_block(free_block);
+        reserved_block.SetByteSize(block_size);
+        // Insert the reserved range and don't combine it with other blocks in
+        // the reserved blocks list.
+        m_reserved_blocks.Insert(reserved_block, false);
+        // Adjust the free range in place since we won't change the sorted
+        // ordering of the m_free_blocks list.
+        free_block.SetRangeBase(reserved_block.GetRangeEnd());
+        free_block.SetByteSize(bytes_left);
+      }
+      LLDB_LOGV(log, "({0}) (size = {1} ({1:x})) => {2:x}", this, size, addr);
+      return addr;
+    }
+  }
+
+  LLDB_LOGV(log, "({0}) (size = {1} ({1:x})) => {2:x}", this, size,
+            LLDB_INVALID_ADDRESS);
+  return LLDB_INVALID_ADDRESS;
+}
+
+bool AllocatedBlock::FreeBlock(addr_t addr) {
+  bool success = false;
+  auto entry_idx = m_reserved_blocks.FindEntryIndexThatContains(addr);
+  if (entry_idx != UINT32_MAX)
+  {
+    m_free_blocks.Insert(m_reserved_blocks.GetEntryRef(entry_idx), true);
+    m_reserved_blocks.RemoveEntryAtIndex(entry_idx);
+    success = true;
+  }
+  Log *log = GetLog(LLDBLog::Process);
+  LLDB_LOGV(log, "({0}) (addr = {1:x}) => {2}", this, addr, success);
+  return success;
+}
+
+AllocatedMemoryCache::AllocatedMemoryCache(Process &process)
+    : m_process(process), m_mutex(), m_memory_map() {}
+
+AllocatedMemoryCache::~AllocatedMemoryCache() = default;
+
+void AllocatedMemoryCache::Clear(bool deallocate_memory) {
+  std::lock_guard<std::recursive_mutex> guard(m_mutex);
+  if (m_process.IsAlive() && deallocate_memory) {
+    PermissionsToBlockMap::iterator pos, end = m_memory_map.end();
+    for (pos = m_memory_map.begin(); pos != end; ++pos)
+      m_process.DoDeallocateMemory(pos->second->GetBaseAddress());
+  }
+  m_memory_map.clear();
+}
+
+AllocatedMemoryCache::AllocatedBlockSP
+AllocatedMemoryCache::AllocatePage(uint32_t byte_size, uint32_t permissions,
+                                   uint32_t chunk_size, Status &error) {
+  AllocatedBlockSP block_sp;
+  const size_t page_size = 4096;
+  const size_t num_pages = (byte_size + page_size - 1) / page_size;
+  const size_t page_byte_size = num_pages * page_size;
+
+  addr_t addr = m_process.DoAllocateMemory(page_byte_size, permissions, error);
+
+  Log *log = GetLog(LLDBLog::Process);
+  if (log) {
+    LLDB_LOGF(log,
+              "Process::DoAllocateMemory (byte_size = 0x%8.8" PRIx32
+              ", permissions = %s) => 0x%16.16" PRIx64,
+              (uint32_t)page_byte_size, GetPermissionsAsCString(permissions),
+              (uint64_t)addr);
+  }
+
+  if (addr != LLDB_INVALID_ADDRESS) {
+    block_sp = std::make_shared<AllocatedBlock>(addr, page_byte_size,
+                                                permissions, chunk_size);
+    m_memory_map.insert(std::make_pair(permissions, block_sp));
+  }
+  return block_sp;
+}
+
+lldb::addr_t AllocatedMemoryCache::AllocateMemory(size_t byte_size,
+                                                  uint32_t permissions,
+                                                  Status &error) {
+  std::lock_guard<std::recursive_mutex> guard(m_mutex);
+
+  addr_t addr = LLDB_INVALID_ADDRESS;
+  std::pair<PermissionsToBlockMap::iterator, PermissionsToBlockMap::iterator>
+      range = m_memory_map.equal_range(permissions);
+
+  for (PermissionsToBlockMap::iterator pos = range.first; pos != range.second;
+       ++pos) {
+    addr = (*pos).second->ReserveBlock(byte_size);
+    if (addr != LLDB_INVALID_ADDRESS)
+      break;
+  }
+
+  if (addr == LLDB_INVALID_ADDRESS) {
+    AllocatedBlockSP block_sp(AllocatePage(byte_size, permissions, 16, error));
+
+    if (block_sp)
+      addr = block_sp->ReserveBlock(byte_size);
+  }
+  Log *log = GetLog(LLDBLog::Process);
+  LLDB_LOGF(log,
+            "AllocatedMemoryCache::AllocateMemory (byte_size = 0x%8.8" PRIx32
+            ", permissions = %s) => 0x%16.16" PRIx64,
+            (uint32_t)byte_size, GetPermissionsAsCString(permissions),
+            (uint64_t)addr);
+  return addr;
+}
+
+bool AllocatedMemoryCache::DeallocateMemory(lldb::addr_t addr) {
+  std::lock_guard<std::recursive_mutex> guard(m_mutex);
+
+  PermissionsToBlockMap::iterator pos, end = m_memory_map.end();
+  bool success = false;
+  for (pos = m_memory_map.begin(); pos != end; ++pos) {
+    if (pos->second->Contains(addr)) {
+      success = pos->second->FreeBlock(addr);
+      break;
+    }
+  }
+  Log *log = GetLog(LLDBLog::Process);
+  LLDB_LOGF(log,
+            "AllocatedMemoryCache::DeallocateMemory (addr = 0x%16.16" PRIx64
+            ") => %i",
+            (uint64_t)addr, success);
+  return success;
+}