[PostEmscripten] Fix calcSegmentOffsets for large offsets (#6260)

Specifically offsets larger than 2^32 which were being interpreted
misinterpreted here as very large int64_t values.

1 files changed, 3 insertions, 4 deletions

diff --git a/src/passes/PostEmscripten.cpp b/src/passes/PostEmscripten.cpp
index 6dc32eaa8..b7d3e9f91 100644
--- a/src/passes/PostEmscripten.cpp
+++ b/src/passes/PostEmscripten.cpp
@@ -95,12 +95,11 @@ static void calcSegmentOffsets(Module& wasm,
             return;
           }
         }
-        auto it = offsets.find(curr->segment);
-        if (it != offsets.end()) {
+        if (offsets.find(curr->segment) != offsets.end()) {
           Fatal() << "Cannot get offset of passive segment initialized "
                      "multiple times";
         }
-        offsets[curr->segment] = dest->value.getInteger();
+        offsets[curr->segment] = dest->value.getUnsigned();
       }
     } searcher(passiveOffsets);
     searcher.walkModule(&wasm);
@@ -317,7 +316,7 @@ struct PostEmscripten : public Pass {
         // The first operand is the function pointer index, which must be
         // constant if we are to optimize it statically.
         if (auto* index = curr->operands[0]->dynCast<Const>()) {
-          size_t indexValue = index->value.getInteger();
+          size_t indexValue = index->value.getUnsigned();
           if (indexValue >= flatTable.names.size()) {
             // UB can lead to indirect calls to invalid pointers.
             return;