[PATCH] D158134: Guard against self-assignment in InputArgList

[Andy Kaylor via Phabricator via llvm-commits]

andrew.w.kaylor created this revision.
andrew.w.kaylor added reviewers: dblaikie, bkramer.
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andrew.w.kaylor requested review of this revision.
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The InputArgList move assignment operator releases memory before copying fields, but it doesn't check against self-assignment. I haven't seen the self-assignment happen, but it doesn't look safe.


https://reviews.llvm.org/D158134

Files:
  llvm/include/llvm/Option/ArgList.h


Index: llvm/include/llvm/Option/ArgList.h
===================================================================
--- llvm/include/llvm/Option/ArgList.h
+++ llvm/include/llvm/Option/ArgList.h
@@ -419,11 +419,13 @@
         NumInputArgStrings(RHS.NumInputArgStrings) {}
 
   InputArgList &operator=(InputArgList &&RHS) {
-    releaseMemory();
-    ArgList::operator=(std::move(RHS));
-    ArgStrings = std::move(RHS.ArgStrings);
-    SynthesizedStrings = std::move(RHS.SynthesizedStrings);
-    NumInputArgStrings = RHS.NumInputArgStrings;
+    if (this != &RHS) {
+      releaseMemory();
+      ArgList::operator=(std::move(RHS));
+      ArgStrings = std::move(RHS.ArgStrings);
+      SynthesizedStrings = std::move(RHS.SynthesizedStrings);
+      NumInputArgStrings = RHS.NumInputArgStrings;
+    }
     return *this;
   }
 


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