[llvm] 80c46c5 - [PoisonChecking] Further clarify file scope comment, and update to match naming now used in code

[Philip Reames via llvm-commits]

Author: Philip Reames
Date: 2020-04-15T14:48:53-07:00
New Revision: 80c46c53bd01ea12495c0e9b4b6c871cef74638d

URL: https://github.com/llvm/llvm-project/commit/80c46c53bd01ea12495c0e9b4b6c871cef74638d
DIFF: https://github.com/llvm/llvm-project/commit/80c46c53bd01ea12495c0e9b4b6c871cef74638d.diff

LOG: [PoisonChecking] Further clarify file scope comment, and update to match naming now used in code

Added: 
    

Modified: 
    llvm/lib/Transforms/Instrumentation/PoisonChecking.cpp

Removed: 
    


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diff  --git a/llvm/lib/Transforms/Instrumentation/PoisonChecking.cpp b/llvm/lib/Transforms/Instrumentation/PoisonChecking.cpp
index 85976b70eaaf..bb90c7bb41b9 100644
--- a/llvm/lib/Transforms/Instrumentation/PoisonChecking.cpp
+++ b/llvm/lib/Transforms/Instrumentation/PoisonChecking.cpp
@@ -21,17 +21,15 @@
 // 2) A propagation rule which translates dynamic information about the poison
 //    state of each input to whether the dynamic output of the instruction
 //    produces poison.
-// 3) A flag validation rule which validates any poison producing flags on the
+// 3) A creation rule which validates any poison producing flags on the
 //    instruction itself (e.g. checks for overflow on nsw).
 // 4) A check rule which traps (to a handler function) if this instruction must
 //    execute undefined behavior given the poison state of it's inputs.
 //
-// At the moment, the UB detection is done in a best effort manner; that is,
-// the resulting code may produce a false negative result (not report UB when
-// it actually exists according to the LangRef spec), but should never produce
-// a false positive (report UB where it doesn't exist).  The intention is to
-// eventually support a "strict" mode which never dynamically reports a false
-// negative at the cost of rejecting some valid inputs to translation.
+// This is a must analysis based transform; that is, the resulting code may
+// produce a false negative result (not report UB when actually exists
+// according to the LangRef spec), but should never produce a false positive
+// (report UB where it doesn't exist).
 //
 // Use cases for this pass include:
 // - Understanding (and testing!) the implications of the definition of poison