[clang] cda88c2 - [clang][bytecode] Check for block pointers in __builtin_strlen() (#187988)

[via cfe-commits]

Author: Timm Baeder
Date: 2026-03-23T09:35:19+01:00
New Revision: cda88c253cbdc832c798cd36cd7670d359ee71bb

URL: https://github.com/llvm/llvm-project/commit/cda88c253cbdc832c798cd36cd7670d359ee71bb
DIFF: https://github.com/llvm/llvm-project/commit/cda88c253cbdc832c798cd36cd7670d359ee71bb.diff

LOG: [clang][bytecode] Check for block pointers in __builtin_strlen() (#187988)

Added: 
    

Modified: 
    clang/lib/AST/ByteCode/InterpBuiltin.cpp
    clang/test/AST/ByteCode/builtins.c

Removed: 
    


################################################################################
diff  --git a/clang/lib/AST/ByteCode/InterpBuiltin.cpp b/clang/lib/AST/ByteCode/InterpBuiltin.cpp
index fa4eb2077e44e..5f8bfcc452387 100644
--- a/clang/lib/AST/ByteCode/InterpBuiltin.cpp
+++ b/clang/lib/AST/ByteCode/InterpBuiltin.cpp
@@ -357,6 +357,9 @@ static bool interp__builtin_strlen(InterpState &S, CodePtr OpPC,
   if (!CheckLive(S, OpPC, StrPtr, AK_Read))
     return false;
 
+  if (!StrPtr.isBlockPointer())
+    return false;
+
   if (!CheckDummy(S, OpPC, StrPtr.block(), AK_Read))
     return false;
 

diff  --git a/clang/test/AST/ByteCode/builtins.c b/clang/test/AST/ByteCode/builtins.c
index 5630a36e1c05b..2d19ccb51de03 100644
--- a/clang/test/AST/ByteCode/builtins.c
+++ b/clang/test/AST/ByteCode/builtins.c
@@ -19,3 +19,6 @@ void f2()  { __builtin_memchr(f2, 0, 1); }
 
 
 _Static_assert(__atomic_is_lock_free(4, (void*)2), ""); // both-error {{not an integral constant expression}}
+
+_Static_assert(__builtin_strlen((void*)0 + 1) == 2, ""); // both-error {{not an integral constant expression}} \
+                                                         // both-note {{cannot perform pointer arithmetic on null pointer}}