commit 1e7353640dfefdb9cef8eaec276a3c84ff098528
author Tom Sepez <tsepez@chromium.org> Fri Oct 06 23:18:33 2023 +0000
committer Pdfium LUCI CQ <pdfium-scoped@luci-project-accounts.iam.gserviceaccount.com> Fri Oct 06 23:18:33 2023 +0000
tree fee0aebd5ff52f3c789e8ff5263e2ebae60c4eb7
parent 7b7a48c4bb307df0c39ad62b827577c7b09c3441

Remove ProbeForLowSeverityLifetimeIssue() from UnownedPtr.

This functionality is now wholly performed on the PA side by its
various raw_ptr<> implementations.

Bug: pdfium:2038
Change-Id: I58007a5fe135e23e0d1346a2265dbef66ee2ebd0
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/112412
Commit-Queue: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>

core/fxcrt/unowned_ptr.h

diff --git a/core/fxcrt/unowned_ptr.h b/core/fxcrt/unowned_ptr.h
index ab92bc6..039ec7e 100644
--- a/core/fxcrt/unowned_ptr.h
+++ b/core/fxcrt/unowned_ptr.h
@@ -68,13 +68,6 @@
 #include "core/fxcrt/unowned_ptr_exclusion.h"
 #include "third_party/base/compiler_specific.h"
 
-namespace pdfium {
-
-template <typename T>
-class span;
-
-}  // namespace pdfium
-
 namespace fxcrt {
 
 template <class T>
@@ -161,7 +154,6 @@
   }
 
   ~UnownedPtr() {
-    ProbeForLowSeverityLifetimeIssue();
     m_pObj = nullptr;
   }
 
@@ -177,7 +169,6 @@
   T* get() const noexcept { return m_pObj; }
 
   T* ExtractAsDangling() {
-    ProbeForLowSeverityLifetimeIssue();
     T* pTemp = nullptr;
     std::swap(pTemp, m_pObj);
     return pTemp;
@@ -188,26 +179,10 @@
   T* operator->() const { return m_pObj; }
 
  private:
-  friend class pdfium::span<T>;
-
   void Reset(T* obj = nullptr) {
-    ProbeForLowSeverityLifetimeIssue();
     m_pObj = obj;
   }
 
-  inline void ProbeForLowSeverityLifetimeIssue() {
-#if defined(ADDRESS_SANITIZER)
-    if (m_pObj)
-      reinterpret_cast<const volatile uint8_t*>(m_pObj)[0];
-#endif
-  }
-
-  inline void ReleaseBadPointer() {
-#if defined(ADDRESS_SANITIZER)
-    m_pObj = nullptr;
-#endif
-  }
-
   UNOWNED_PTR_EXCLUSION T* m_pObj = nullptr;
 };
 

third_party/base/containers/span.h

diff --git a/third_party/base/containers/span.h b/third_party/base/containers/span.h
index 660d92c..435fafa 100644
--- a/third_party/base/containers/span.h
+++ b/third_party/base/containers/span.h
@@ -228,13 +228,12 @@
   constexpr span(const span<U>& other) : span(other.data(), other.size()) {}
   span& operator=(const span& other) noexcept {
     if (this != &other) {
-      ReleaseEmptySpan();
       data_ = other.data_;
       size_ = other.size_;
     }
     return *this;
   }
-  ~span() noexcept { ReleaseEmptySpan(); }
+  ~span() noexcept = default;
 
   // [span.sub], span subviews
   const span first(size_t count) const {
@@ -299,15 +298,6 @@
   }
 
  private:
-  void ReleaseEmptySpan() noexcept {
-#if defined(ADDRESS_SANITIZER) && !defined(UNOWNED_PTR_IS_BASE_RAW_PTR)
-    // Empty spans might point to byte N+1 of a N-byte object, legal for
-    // C pointers but not UnownedPtrs.
-    if (!size_)
-      data_.ReleaseBadPointer();
-#endif
-  }
-
 #if defined(UNOWNED_PTR_IS_BASE_RAW_PTR)
   raw_ptr<T, AllowPtrArithmetic> data_ = nullptr;
 #else