[llvm] f415d74 - [SampleProfile] Handle the case when the option `MaxNumPromotions` is zero.

[via llvm-commits]

Author: minglotus-6
Date: 2022-02-22T21:44:32-08:00
New Revision: f415d74d1df3995795c889333d493b0dcc31a863

URL: https://github.com/llvm/llvm-project/commit/f415d74d1df3995795c889333d493b0dcc31a863
DIFF: https://github.com/llvm/llvm-project/commit/f415d74d1df3995795c889333d493b0dcc31a863.diff

LOG: [SampleProfile] Handle the case when the option `MaxNumPromotions` is zero.

In places where `MaxNumPromotions` is used to allocated an array, bail out early to prevent allocating an array of length 0.

Differential Revision: https://reviews.llvm.org/D120295

Added: 
    

Modified: 
    llvm/lib/Transforms/IPO/SampleProfile.cpp

Removed: 
    


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diff  --git a/llvm/lib/Transforms/IPO/SampleProfile.cpp b/llvm/lib/Transforms/IPO/SampleProfile.cpp
index fc0b6f5991a1f..5985281019b0a 100644
--- a/llvm/lib/Transforms/IPO/SampleProfile.cpp
+++ b/llvm/lib/Transforms/IPO/SampleProfile.cpp
@@ -841,6 +841,13 @@ static void
 updateIDTMetaData(Instruction &Inst,
                   const SmallVectorImpl<InstrProfValueData> &CallTargets,
                   uint64_t Sum) {
+  // Bail out early if MaxNumPromotions is zero.
+  // This prevents allocating an array of zero length below.
+  //
+  // Note `updateIDTMetaData` is called in two places so check
+  // `MaxNumPromotions` inside it.
+  if (MaxNumPromotions == 0)
+    return;
   uint32_t NumVals = 0;
   // OldSum is the existing total count in the value profile data.
   uint64_t OldSum = 0;
@@ -924,6 +931,10 @@ updateIDTMetaData(Instruction &Inst,
 bool SampleProfileLoader::tryPromoteAndInlineCandidate(
     Function &F, InlineCandidate &Candidate, uint64_t SumOrigin, uint64_t &Sum,
     SmallVector<CallBase *, 8> *InlinedCallSite) {
+  // Bail out early if MaxNumPromotions is zero.
+  // This prevents allocating an array of zero length in callees below.
+  if (MaxNumPromotions == 0)
+    return false;
   auto CalleeFunctionName = Candidate.CalleeSamples->getFuncName();
   auto R = SymbolMap.find(CalleeFunctionName);
   if (R == SymbolMap.end() || !R->getValue())