[PATCH] D95510: Diagnose if a SLEB128 is too large to fit in an int64_t.

[Richard Smith - zygoloid via Phabricator via llvm-commits]

rsmith created this revision.
rsmith added reviewers: dblaikie, aardappel.
Herald added subscribers: dexonsmith, sunfish, hiraditya, sbc100.
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Previously we'd hit UB due to an invalid left shift operand.

Also fix the WASM emitter to properly use SLEB128 encoding instead of
ULEB128 encoding for signed fields so that negative numbers don't
result in overly-large values that we can't read back any more.

In passing, don't diagnose a non-canonical ULEB128 that fits in a uint64_t but
has redundant trailing zero bytes.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D95510

Files:
  llvm/include/llvm/Support/LEB128.h
  llvm/lib/ObjectYAML/WasmEmitter.cpp
  llvm/unittests/Support/LEB128Test.cpp

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