[WIP][Attributor] Check range size before constant fold load

shiltian · shiltian · commit 35143206ab0d · 2025-07-30T12:09:52.000-04:00
If the range size doesn't match the type size, it might read wrong data.
diff --git a/llvm/lib/Transforms/IPO/Attributor.cpp b/llvm/lib/Transforms/IPO/Attributor.cpp
@@ -272,6 +272,9 @@ AA::getInitialValueForObj(Attributor &A, const AbstractAttribute &QueryingAA,
   }
 
   if (RangePtr && !RangePtr->offsetOrSizeAreUnknown()) {
+    int64_t StorageSize = DL.getTypeStoreSize(&Ty);
+    if (StorageSize != RangePtr->Size)
+      return nullptr;
     APInt Offset = APInt(64, RangePtr->Offset);
     return ConstantFoldLoadFromConst(Initializer, &Ty, Offset, DL);
   }

Original file line number	Diff line number	Diff line change
`@@ -272,6 +272,9 @@ AA::getInitialValueForObj(Attributor &A, const AbstractAttribute &QueryingAA,`
`272`	`272`	`}`
`273`	`273`
`274`	`274`	`if (RangePtr && !RangePtr->offsetOrSizeAreUnknown()) {`
	`275`	`+ int64_t StorageSize = DL.getTypeStoreSize(&Ty);`
	`276`	`+ if (StorageSize != RangePtr->Size)`
	`277`	`+ return nullptr;`
`275`	`278`	`APInt Offset = APInt(64, RangePtr->Offset);`
`276`	`279`	`return ConstantFoldLoadFromConst(Initializer, &Ty, Offset, DL);`
`277`	`280`	`}`