[clang] ff96ad8 - [clang][Interp][NFC] Add Pointer::isDereferencable()

[Timm Bäder via cfe-commits]

Author: Timm Bäder
Date: 2024-07-16T07:24:08+02:00
New Revision: ff96ad84f52022af295d11749f106480e7292a89

URL: https://github.com/llvm/llvm-project/commit/ff96ad84f52022af295d11749f106480e7292a89
DIFF: https://github.com/llvm/llvm-project/commit/ff96ad84f52022af295d11749f106480e7292a89.diff

LOG: [clang][Interp][NFC] Add Pointer::isDereferencable()

We currently have a few places where we check whether a pointer can
be read from at all. Add a function to do that.

Added: 
    

Modified: 
    clang/lib/AST/Interp/Pointer.h

Removed: 
    


################################################################################
diff  --git a/clang/lib/AST/Interp/Pointer.h b/clang/lib/AST/Interp/Pointer.h
index 6e9e8675306ef..28bc42985adb2 100644
--- a/clang/lib/AST/Interp/Pointer.h
+++ b/clang/lib/AST/Interp/Pointer.h
@@ -584,6 +584,7 @@ class Pointer {
     assert(isLive() && "Invalid pointer");
     assert(isBlockPointer());
     assert(asBlockPointer().Pointee);
+    assert(isDereferencable());
     assert(Offset + sizeof(T) <=
            asBlockPointer().Pointee->getDescriptor()->getAllocSize());
 
@@ -603,6 +604,17 @@ class Pointer {
                                  sizeof(InitMapPtr))[I];
   }
 
+  /// Whether this block can be read from at all. This is only true for
+  /// block pointers that point to a valid location inside that block.
+  bool isDereferencable() const {
+    if (!isBlockPointer())
+      return false;
+    if (isPastEnd())
+      return false;
+
+    return true;
+  }
+
   /// Initializes a field.
   void initialize() const;
   /// Activats a field.