[Lldb-commits] [PATCH] D123098: [lldb] Fix undefined behavior: left shift of negative value

[Jonas Devlieghere via Phabricator via lldb-commits]

JDevlieghere created this revision.
JDevlieghere added reviewers: aprantl, jingham, jasonmolenda.
Herald added a project: All.
JDevlieghere requested review of this revision.

Fix undefined behavior in AppleObjCRuntimeV2 where we were left shifting a 
signed value.

rdar://91242879


https://reviews.llvm.org/D123098

Files:
  
lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntimeV2.cpp


Index: 
lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntimeV2.cpp
===================================================================
--- 
lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntimeV2.cpp
+++ 
lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntimeV2.cpp
@@ -2765,7 +2765,7 @@
       (((uint64_t)unobfuscated << m_objc_debug_taggedpointer_payload_lshift) >>
        m_objc_debug_taggedpointer_payload_rshift);
   int64_t data_payload_signed =
-      ((int64_t)((int64_t)unobfuscated
+      ((int64_t)((uint64_t)unobfuscated
                  << m_objc_debug_taggedpointer_payload_lshift) >>
        m_objc_debug_taggedpointer_payload_rshift);
   return ClassDescriptorSP(new ClassDescriptorV2Tagged(


STAMPS
actor(@JDevlieghere) application(Differential) author(@JDevlieghere) 
herald(H576) herald(H864) monogram(D123098) object-type(DREV) 
phid(PHID-DREV-vn5s2fbg65fw42dy4msc) reviewer(@aprantl) reviewer(@jasonmolenda) 
reviewer(@jingham) revision-status(needs-review) subscriber(@lldb-commits) 
tag(#all) via(web)


Index: lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntimeV2.cpp
===================================================================
--- lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntimeV2.cpp
+++ lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntimeV2.cpp
@@ -2765,7 +2765,7 @@
       (((uint64_t)unobfuscated << m_objc_debug_taggedpointer_payload_lshift) >>
        m_objc_debug_taggedpointer_payload_rshift);
   int64_t data_payload_signed =
-      ((int64_t)((int64_t)unobfuscated
+      ((int64_t)((uint64_t)unobfuscated
                  << m_objc_debug_taggedpointer_payload_lshift) >>
        m_objc_debug_taggedpointer_payload_rshift);
   return ClassDescriptorSP(new ClassDescriptorV2Tagged(

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