[llvm-branch-commits] [sanitizer] Add MemCpyAccessible (PR #112794)

[Florian Mayer via llvm-branch-commits]

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@@ -219,6 +219,32 @@ static void StopStackDepotBackgroundThread() {
 static void StopStackDepotBackgroundThread() {}
 #endif
 
+void MemCpyAccessible(void *dest, const void *src, uptr n) {
+  if (TryMemCpy(dest, src, n))
+    return;
+
+  const uptr page_size = GetPageSize();
+  uptr b = reinterpret_cast<uptr>(src);
+  uptr b_up = RoundUpTo(b, page_size);
+
+  uptr e = reinterpret_cast<uptr>(src) + n;
+  uptr e_down = RoundDownTo(e, page_size);
+
+  auto copy_or_zero = [dest, src](uptr b, uptr e) {
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fmayer wrote:

Don't reuse `b` and `e` in and outside of the lambda

https://github.com/llvm/llvm-project/pull/112794