[llvm] c20a800 - [ObjC][ARC] Fix UB in ObjCARCOpt with -enable-objc-arc-opts=false

[Stefan Gränitz via llvm-commits]

Author: Stefan Gränitz
Date: 2022-11-23T11:30:39+01:00
New Revision: c20a80092c15c6da5de2e5829be88e2009d5899f

URL: https://github.com/llvm/llvm-project/commit/c20a80092c15c6da5de2e5829be88e2009d5899f
DIFF: https://github.com/llvm/llvm-project/commit/c20a80092c15c6da5de2e5829be88e2009d5899f.diff

LOG: [ObjC][ARC] Fix UB in ObjCARCOpt with -enable-objc-arc-opts=false

When ObjCARCOpt::run() returned early, Changed and CFGChanged were never initialized. CFGChanged is read unconditionally afterwards. This came up in the course of D137942.

Added: 
    

Modified: 
    llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp

Removed: 
    


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diff  --git a/llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp b/llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
index 9834679ef51fc..d703468f6353b 100644
--- a/llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
+++ b/llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
@@ -481,8 +481,8 @@ namespace {
 
   /// The main ARC optimization pass.
 class ObjCARCOpt {
-  bool Changed;
-  bool CFGChanged;
+  bool Changed = false;
+  bool CFGChanged = false;
   ProvenanceAnalysis PA;
 
   /// A cache of references to runtime entry point constants.