[PATCH] D41457: [libfuzzer] Fix UB when calculating Log(0) in StackDepthStepFunction().

[Max Moroz via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rCRT321211: [libfuzzer] Fix UB when calculating Log(0) in StackDepthStepFunction(). (authored by Dor1s, committed by ).

Changed prior to commit:
  https://reviews.llvm.org/D41457?vs=127761&id=127768#toc

Repository:
  rCRT Compiler Runtime

https://reviews.llvm.org/D41457

Files:
  lib/fuzzer/FuzzerTracePC.h


Index: lib/fuzzer/FuzzerTracePC.h
===================================================================
--- lib/fuzzer/FuzzerTracePC.h
+++ lib/fuzzer/FuzzerTracePC.h
@@ -276,6 +276,7 @@
 
   // Step function, grows similar to 8 * Log_2(A).
   auto StackDepthStepFunction = [](uint32_t A) -> uint32_t {
+    if (!A) return A;
     uint32_t Log2 = Log(A);
     if (Log2 < 3) return A;
     Log2 -= 3;


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