1 files changed, 23 insertions, 6 deletions

diff --git a/src/binary-reader.cc b/src/binary-reader.cc
index 341e8861..ee8eed49 100644
--- a/src/binary-reader.cc
+++ b/src/binary-reader.cc
@@ -122,6 +122,8 @@ class BinaryReader {
   [[nodiscard]] Result ReadIndex(Index* index, const char* desc);
   [[nodiscard]] Result ReadOffset(Offset* offset, const char* desc);
   [[nodiscard]] Result ReadAlignment(Address* align_log2, const char* desc);
+  [[nodiscard]] Result CheckAlignment(Address* align_log2, const char* desc);
+  [[nodiscard]] Result TakeHasMemidx(Address* align_log2, bool* has_memidx);
   [[nodiscard]] Result ReadMemidx(Index* memidx, const char* desc);
   [[nodiscard]] Result ReadMemLocation(Address* alignment_log2,
                                        Index* memidx,
@@ -432,12 +434,24 @@ Result BinaryReader::ReadOffset(Offset* offset, const char* desc) {
 Result BinaryReader::ReadAlignment(Address* alignment_log2, const char* desc) {
   uint32_t value;
   CHECK_RESULT(ReadU32Leb128(&value, desc));
-  if (value >= 128 ||
-      (value >= 32 && !options_.features.multi_memory_enabled())) {
-    PrintError("invalid %s: %u", desc, value);
+  *alignment_log2 = value;
+  return Result::Ok;
+}
+
+Result BinaryReader::CheckAlignment(Address* align_log2, const char* desc) {
+  uint32_t value = *align_log2;
+  if (value >= 32) {
+    PrintError("invalid %s: %" PRIu32, desc, value);
     return Result::Error;
   }
-  *alignment_log2 = value;
+  return Result::Ok;
+}
+
+Result BinaryReader::TakeHasMemidx(Address* align_log2, bool* has_memidx) {
+  // extract the has_memidx flag
+  *has_memidx = (*align_log2 >> 6) & 1;
+  // then clear it
+  *align_log2 &= ~(1 << 6);
   return Result::Ok;
 }
 
@@ -453,12 +467,14 @@ Result BinaryReader::ReadMemLocation(Address* alignment_log2,
                                      const char* desc_memidx,
                                      const char* desc_offset,
                                      uint8_t* lane_val) {
+  bool has_memidx = false;
   CHECK_RESULT(ReadAlignment(alignment_log2, desc_align));
+  CHECK_RESULT(TakeHasMemidx(alignment_log2, &has_memidx));
+  CHECK_RESULT(CheckAlignment(alignment_log2, desc_align));
   *memidx = 0;
-  if (*alignment_log2 >> 6) {
+  if (has_memidx) {
     ERROR_IF(!options_.features.multi_memory_enabled(),
              "multi_memory not allowed");
-    *alignment_log2 = *alignment_log2 & ((1 << 6) - 1);
     CHECK_RESULT(ReadMemidx(memidx, desc_memidx));
   }
   CHECK_RESULT(ReadAddress(offset, 0, desc_offset));
@@ -2267,6 +2283,7 @@ Result BinaryReader::ReadLinkingSection(Offset section_size) {
           uint32_t flags;
           CHECK_RESULT(ReadStr(&name, "segment name"));
           CHECK_RESULT(ReadAlignment(&alignment_log2, "segment alignment"));
+          CHECK_RESULT(CheckAlignment(&alignment_log2, "segment alignment"));
           CHECK_RESULT(ReadU32Leb128(&flags, "segment flags"));
           CALLBACK(OnSegmentInfo, i, name, alignment_log2, flags);
         }