2 files changed, 54 insertions, 2 deletions

diff --git a/lldb/source/Target/Process.cpp b/lldb/source/Target/Process.cpp
index 3176852..fb9e7eb 100644
--- a/lldb/source/Target/Process.cpp
+++ b/lldb/source/Target/Process.cpp
@@ -1971,6 +1971,49 @@ size_t Process::ReadMemory(addr_t addr, void *buf, size_t size, Status &error) {
   }
 }
 
+llvm::SmallVector<llvm::MutableArrayRef<uint8_t>>
+Process::ReadMemoryRanges(llvm::ArrayRef<Range<lldb::addr_t, size_t>> ranges,
+                          llvm::MutableArrayRef<uint8_t> buffer) {
+  auto total_ranges_len = llvm::sum_of(
+      llvm::map_range(ranges, [](auto range) { return range.size; }));
+  // If the buffer is not large enough, this is a programmer error.
+  // In production builds, gracefully fail by returning a length of 0 for all
+  // ranges.
+  assert(buffer.size() >= total_ranges_len && "provided buffer is too short");
+  if (buffer.size() < total_ranges_len) {
+    llvm::MutableArrayRef<uint8_t> empty;
+    return {ranges.size(), empty};
+  }
+
+  llvm::SmallVector<llvm::MutableArrayRef<uint8_t>> results;
+
+  // While `buffer` has space, take the next requested range and read
+  // memory into a `buffer` piece, then slice it to remove the used memory.
+  for (auto [addr, range_len] : ranges) {
+    Status status;
+    size_t num_bytes_read =
+        ReadMemoryFromInferior(addr, buffer.data(), range_len, status);
+    // FIXME: ReadMemoryFromInferior promises to return 0 in case of errors, but
+    // it doesn't; it never checks for errors.
+    if (status.Fail())
+      num_bytes_read = 0;
+
+    assert(num_bytes_read <= range_len && "read more than requested bytes");
+    if (num_bytes_read > range_len) {
+      // In production builds, gracefully fail by returning length zero for this
+      // range.
+      results.emplace_back();
+      continue;
+    }
+
+    results.push_back(buffer.take_front(num_bytes_read));
+    // Slice buffer to remove the used memory.
+    buffer = buffer.drop_front(num_bytes_read);
+  }
+
+  return results;
+}
+
 void Process::DoFindInMemory(lldb::addr_t start_addr, lldb::addr_t end_addr,
                              const uint8_t *buf, size_t size,
                              AddressRanges &matches, size_t alignment,
diff --git a/lldb/source/Target/StopInfo.cpp b/lldb/source/Target/StopInfo.cpp
index 7fa1fc5..e9e534a 100644
--- a/lldb/source/Target/StopInfo.cpp
+++ b/lldb/source/Target/StopInfo.cpp
@@ -87,11 +87,15 @@ bool StopInfo::HasTargetRunSinceMe() {
 namespace lldb_private {
 class StopInfoBreakpoint : public StopInfo {
 public:
+  // We use a "breakpoint preserving BreakpointLocationCollection because we
+  // may need to hand out the "breakpoint hit" list as any point, potentially
+  // after the breakpoint has been deleted.  But we still need to refer to them.
   StopInfoBreakpoint(Thread &thread, break_id_t break_id)
       : StopInfo(thread, break_id), m_should_stop(false),
         m_should_stop_is_valid(false), m_should_perform_action(true),
         m_address(LLDB_INVALID_ADDRESS), m_break_id(LLDB_INVALID_BREAK_ID),
-        m_was_all_internal(false), m_was_one_shot(false) {
+        m_was_all_internal(false), m_was_one_shot(false),
+        m_async_stopped_locs(true) {
     StoreBPInfo();
   }
 
@@ -99,7 +103,8 @@ public:
       : StopInfo(thread, break_id), m_should_stop(should_stop),
         m_should_stop_is_valid(true), m_should_perform_action(true),
         m_address(LLDB_INVALID_ADDRESS), m_break_id(LLDB_INVALID_BREAK_ID),
-        m_was_all_internal(false), m_was_one_shot(false) {
+        m_was_all_internal(false), m_was_one_shot(false),
+        m_async_stopped_locs(true) {
     StoreBPInfo();
   }
 
@@ -699,6 +704,10 @@ private:
   lldb::break_id_t m_break_id;
   bool m_was_all_internal;
   bool m_was_one_shot;
+  /// The StopInfoBreakpoint lives after the stop, and could get queried
+  /// at any time so we need to make sure that it keeps the breakpoints for
+  /// each of the locations it records alive while it is around.  That's what
+  /// The BreakpointPreservingLocationCollection does.
   BreakpointLocationCollection m_async_stopped_locs;
 };