[compiler-rt] [llvm] [Memprof] Adds instrumentation support for memprof with histograms. (PR #100834)

[Teresa Johnson via llvm-commits]

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@@ -489,16 +489,38 @@ void MemProfiler::instrumentAddress(Instruction *OrigIns,
     return;
   }
 
-  // Create an inline sequence to compute shadow location, and increment the
-  // value by one.
-  Type *ShadowTy = Type::getInt64Ty(*C);
-  Type *ShadowPtrTy = PointerType::get(ShadowTy, 0);
-  Value *ShadowPtr = memToShadow(AddrLong, IRB);
-  Value *ShadowAddr = IRB.CreateIntToPtr(ShadowPtr, ShadowPtrTy);
-  Value *ShadowValue = IRB.CreateLoad(ShadowTy, ShadowAddr);
-  Value *Inc = ConstantInt::get(Type::getInt64Ty(*C), 1);
-  ShadowValue = IRB.CreateAdd(ShadowValue, Inc);
-  IRB.CreateStore(ShadowValue, ShadowAddr);
+  if (ClHistogram) {
+    Type *ShadowTy = Type::getInt8Ty(*C);
+    Type *ShadowPtrTy = PointerType::get(ShadowTy, 0);
+    Value *Shadow = IRB.CreateAnd(AddrLong, Mapping.Mask);
+    Shadow = IRB.CreateLShr(Shadow, Mapping.Scale);
+    assert(DynamicShadowOffset);
+    Value *ShadowInteger = IRB.CreateAdd(Shadow, DynamicShadowOffset);
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teresajohnson wrote:

Can't the above 4 lines just reuse memToShadow?

https://github.com/llvm/llvm-project/pull/100834