[Mlir-commits] [mlir] [MLIR][Bytecode] Followup 8106c81 (PR #157136)

[Nikhil Kalra]

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@@ -300,8 +298,19 @@ class EncodingReader {
       // alignment of the root buffer. If it is not, we cannot safely guarantee
       // that the specified alignment is globally correct.
       //
-      // E.g. if the buffer is 8k aligned and the section is 16k aligned,
-      // we could end up at an offset of 24k, which is not globally 16k aligned.
+      // E.g. if the buffer is 8k aligned and the section is marked to be 16k
+      // aligned:
+      // - (a) the alignTo call early returns when the pointer is 16k
+      // aligned but given the original 8k alignment we could offset into the
+      // padding by ~8k giving us 16k pointer alignment leaving another ~8k of
+      // padding in the bytecode file that will inadvertently be read when we
+      // attempt to parse the next section.
+      // - (b) we update alignTo to align relative to the start of the buffer,
+      // but given an 8k aligned buffer and section alignment of 16k, we could
+      // end up with a pointer that is 24k aligned (8k start alignment + 16k
+      // offset) instead of globally 16k aligned (versus 16k start alignment +
+      // 16k offset). This would result in incorrectly stated alignment for
+      // resources that reference data inside of the bytecode buffer.
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nikalra wrote:

done

https://github.com/llvm/llvm-project/pull/157136