[PATCH] D80354: [lld][WebAssembly] Do not emit initialization for .bss segments

Wed May 20 20:57:34 PDT 2020

sbc100 added inline comments.

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Comment at: lld/test/wasm/data-segments.ll:65
+; PASSIVE-NEXT:        Body:            41B4D60041004101FE480200044041B4D6004101427FFE0102001A054180084100410DFC08000041900841004114FC08010041B4D6004102FE17020041B4D600417FFE0002001A0BFC0900FC09010B
+
 ; PASSIVE-NEXT:  - Index:           2
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tlively wrote:
> There used to be 3 data.drop (FC09) instructions at the end, but now you can see that there are only two, as expected.
So we doulbly dropping a segment before?

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Comment at: lld/wasm/Writer.cpp:832
           writeUleb128(os, WASM_OPCODE_MEMORY_INIT, "memory.init");
           writeUleb128(os, s->index, "segment index immediate");
           writeU8(os, 0, "memory index immediate");
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So was the crash was happening when there was only a bss segment?  And somehow having more than one segment was masking the crash?  

Should we add a specific test case for that?  An example that would have previously caused and invalid binary would be good.

I'm stil now clear why we didn't see this is more of our emscripten test cases,

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D80354/new/

https://reviews.llvm.org/D80354