[llvm] [Attributor] New attribute to identify what byte ranges are alive for an allocation (PR #66148)

[Vidhush Singhal via llvm-commits]

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@@ -12658,6 +12669,268 @@ struct AAAddressSpaceCallSiteArgument final : AAAddressSpaceImpl {
 };
 } // namespace
 
+/// ----------- Allocation Info ----------
+namespace {
+struct AAAllocationInfoImpl : public AAAllocationInfo {
+  AAAllocationInfoImpl(const IRPosition &IRP, Attributor &A)
+      : AAAllocationInfo(IRP, A) {}
+
+  std::optional<TypeSize> getAllocatedSize() const override {
+    assert(isValidState() && "the AA is invalid");
+    return AssumedAllocatedSize;
+  }
+
+  bool isaMallocInst(Instruction *I) {
+    CallInst *Call = dyn_cast<CallInst>(I);
+    auto CallName = Call->getCalledFunction()->getName();
+    if (CallName.str() == "malloc")
+      return true;
+
+    return false;
+  };
+
+  ChangeStatus updateImpl(Attributor &A) override {
+
+    Instruction *I = getIRPosition().getCtxI();
+
+    const IRPosition &IRP = getIRPosition();
+
+    if (!(isa<AllocaInst>(I) || isaMallocInst(I)))
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vidsinghal wrote:

There are a few functions in MemoryBuiltins.h
`isAllocLikeFn`  should work here. 

https://github.com/llvm/llvm-project/pull/66148