[Lldb-commits] [lldb] [lldb] Implement Process::ReadMemoryRanges (PR #163651)

[David Spickett via lldb-commits]

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@@ -1971,6 +1971,45 @@ 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 empty chunks.
+  assert(buffer.size() >= total_ranges_len);
+  if (buffer.size() < total_ranges_len)
+    return llvm::SmallVector<llvm::MutableArrayRef<uint8_t>>(ranges.size());
+
+  llvm::SmallVector<llvm::MutableArrayRef<uint8_t>> results;
+
+  // While `buffer` has space, take the next requested range and read
+  // memory into a `buffer` chunk, then slice it to remove the used chunk.
+  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 an empty chunk.
+      results.emplace_back();
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DavidSpickett wrote:

Explicit zero here please.

https://github.com/llvm/llvm-project/pull/163651