[NFC] [HWASan] Add link to proof for address calculation

[fmayer]

No description provided.

[llvmbot]

@llvm/pr-subscribers-compiler-rt-sanitizer

@llvm/pr-subscribers-llvm-transforms

Author: Florian Mayer (fmayer)

Changes

---

Full diff: https://github.com/llvm/llvm-project/pull/86367.diff

1 Files Affected:

• (modified) llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp (+2)

diff --git a/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
index 3c95610fa3e80b..c8f7ed448279f3 100644
--- a/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
@@ -1104,6 +1104,8 @@ void HWAddressSanitizer::tagAlloca(IRBuilder<> &IRB, AllocaInst *AI, Value *Tag,
     // FIXME: the interceptor is not as fast as real memset. Consider lowering
     // llvm.memset right here into either a sequence of stores, or a call to
     // hwasan_tag_memory.
+    // Mechanical proof of this address calculation can be found at:
+    // https://github.com/google/sanitizers/blob/master/hwaddress-sanitizer/prove_hwasanwrap.smt2
     if (ShadowSize)
       IRB.CreateMemSet(ShadowPtr, Tag, ShadowSize, Align(1));
     if (Size != AlignedSize) {

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[github-actions]

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