[clang] fc9052e - [clang][bytecode] Check __builtin_memcpy for null pointers (#118313)

[via cfe-commits]

Author: Timm Baeder
Date: 2024-12-03T03:36:57+01:00
New Revision: fc9052ee258e35c5aaba3dc2c1419870975f3a7a

URL: https://github.com/llvm/llvm-project/commit/fc9052ee258e35c5aaba3dc2c1419870975f3a7a
DIFF: https://github.com/llvm/llvm-project/commit/fc9052ee258e35c5aaba3dc2c1419870975f3a7a.diff

LOG: [clang][bytecode] Check __builtin_memcpy for null pointers (#118313)

Added: 
    

Modified: 
    clang/lib/AST/ByteCode/InterpBuiltin.cpp
    clang/test/AST/ByteCode/builtin-functions.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/AST/ByteCode/InterpBuiltin.cpp b/clang/lib/AST/ByteCode/InterpBuiltin.cpp
index db3703a60db699..d7e32c491b03bc 100644
--- a/clang/lib/AST/ByteCode/InterpBuiltin.cpp
+++ b/clang/lib/AST/ByteCode/InterpBuiltin.cpp
@@ -1796,6 +1796,14 @@ static bool interp__builtin_memcpy(InterpState &S, CodePtr OpPC,
     return true;
   }
 
+  if (SrcPtr.isZero() || DestPtr.isZero()) {
+    Pointer DiagPtr = (SrcPtr.isZero() ? SrcPtr : DestPtr);
+    S.FFDiag(S.Current->getSource(OpPC), diag::note_constexpr_memcpy_null)
+        << /*IsMove=*/false << /*IsWchar=*/false << !SrcPtr.isZero()
+        << DiagPtr.toDiagnosticString(S.getASTContext());
+    return false;
+  }
+
   if (!DoBitCastPtr(S, OpPC, SrcPtr, DestPtr))
     return false;
 

diff  --git a/clang/test/AST/ByteCode/builtin-functions.cpp b/clang/test/AST/ByteCode/builtin-functions.cpp
index 9a6a31b5ec4c06..dfee35d6399a6c 100644
--- a/clang/test/AST/ByteCode/builtin-functions.cpp
+++ b/clang/test/AST/ByteCode/builtin-functions.cpp
@@ -1138,4 +1138,12 @@ namespace BuiltinMemcpy {
     return b;
   }
   static_assert(simple() == 12);
+
+
+  extern struct Incomplete incomplete;
+  constexpr struct Incomplete *null_incomplete = 0;
+  static_assert(__builtin_memcpy(null_incomplete, null_incomplete, sizeof(wchar_t))); // both-error {{not an integral constant expression}} \
+                                                                                      // both-note {{source of 'memcpy' is nullptr}}
+
+
 }