[llvm-branch-commits] [llvm] [BOLT] Gadget scanner: detect signing oracles (PR #134146)

[Kristof Beyls via llvm-branch-commits]

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@@ -622,6 +628,40 @@ class MCPlusBuilder {
     return std::make_pair(getNoRegister(), getNoRegister());
   }
 
+  /// Analyzes if a pointer is checked to be valid by the end of BB.
+  ///
+  /// It is possible for pointer authentication instructions not to terminate
+  /// the program abnormally on authentication failure and return some *invalid
+  /// pointer* instead (like it is done on AArch64 when FEAT_FPAC is not
+  /// implemented). This might be enough to crash on invalid memory access
+  /// when the pointer is later used as the destination of load/store or branch
+  /// instruction. On the other hand, when the pointer is not used right away,
+  /// it may be important for the compiler to check the address explicitly not
+  /// to introduce signing or authentication oracle.
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kbeyls wrote:

either "a signing..." or "oracles"?

https://github.com/llvm/llvm-project/pull/134146