From 1f04cc1f23b1a86d79ee1a9afa59180ac1699ab5 Mon Sep 17 00:00:00 2001
From: Aayush Rajasekaran <arajasek94@gmail.com>
Date: Thu, 16 Dec 2021 23:59:26 -0500
Subject: [PATCH] VM: Circ supply should be constant per epoch

---
 chain/gen/genesis/genesis.go |  6 +++++-
 chain/vm/vm.go               | 19 ++++++++++++++-----
 conformance/driver.go        |  8 ++++++++
 3 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/chain/gen/genesis/genesis.go b/chain/gen/genesis/genesis.go
index 29f03e2af..45387df50 100644
--- a/chain/gen/genesis/genesis.go
+++ b/chain/gen/genesis/genesis.go
@@ -479,6 +479,10 @@ func VerifyPreSealedData(ctx context.Context, cs *store.ChainStore, sys vm.Sysca
 	verifNeeds := make(map[address.Address]abi.PaddedPieceSize)
 	var sum abi.PaddedPieceSize
 
+	csc := func(context.Context, abi.ChainEpoch, *state.StateTree) (abi.TokenAmount, error) {
+		return big.Zero(), nil
+	}
+
 	vmopt := vm.VMOpts{
 		StateBase:      stateroot,
 		Epoch:          0,
@@ -486,7 +490,7 @@ func VerifyPreSealedData(ctx context.Context, cs *store.ChainStore, sys vm.Sysca
 		Bstore:         cs.StateBlockstore(),
 		Actors:         filcns.NewActorRegistry(),
 		Syscalls:       mkFakedSigSyscalls(sys),
-		CircSupplyCalc: nil,
+		CircSupplyCalc: csc,
 		NtwkVersion: func(_ context.Context, _ abi.ChainEpoch) network.Version {
 			return nv
 		},
diff --git a/chain/vm/vm.go b/chain/vm/vm.go
index 16ad5e2a4..d569dbbbf 100644
--- a/chain/vm/vm.go
+++ b/chain/vm/vm.go
@@ -202,9 +202,7 @@ type (
 )
 
 type VM struct {
-	cstate *state.StateTree
-	// TODO: Is base actually used? Can we delete it?
-	base           cid.Cid
+	cstate         *state.StateTree
 	cst            *cbor.BasicIpldStore
 	buf            *blockstore.BufferedBlockstore
 	blockHeight    abi.ChainEpoch
@@ -214,6 +212,7 @@ type VM struct {
 	ntwkVersion    NtwkVersionGetter
 	baseFee        abi.TokenAmount
 	lbStateGet     LookbackStateGetter
+	baseCircSupply abi.TokenAmount
 
 	Syscalls SyscallBuilder
 }
@@ -239,9 +238,13 @@ func NewVM(ctx context.Context, opts *VMOpts) (*VM, error) {
 		return nil, err
 	}
 
+	baseCirc, err := opts.CircSupplyCalc(ctx, opts.Epoch, state)
+	if err != nil {
+		return nil, err
+	}
+
 	return &VM{
 		cstate:         state,
-		base:           opts.StateBase,
 		cst:            cst,
 		buf:            buf,
 		blockHeight:    opts.Epoch,
@@ -251,6 +254,7 @@ func NewVM(ctx context.Context, opts *VMOpts) (*VM, error) {
 		ntwkVersion:    opts.NtwkVersion,
 		Syscalls:       opts.Syscalls,
 		baseFee:        opts.BaseFee,
+		baseCircSupply: baseCirc,
 		lbStateGet:     opts.LookbackState,
 	}, nil
 }
@@ -859,7 +863,12 @@ func (vm *VM) GetNtwkVersion(ctx context.Context, ce abi.ChainEpoch) network.Ver
 }
 
 func (vm *VM) GetCircSupply(ctx context.Context) (abi.TokenAmount, error) {
-	return vm.circSupplyCalc(ctx, vm.blockHeight, vm.cstate)
+	// Before v15, this was recalculated on each invocation as the state tree was mutated
+	if vm.GetNtwkVersion(ctx, vm.blockHeight) <= network.Version14 {
+		return vm.circSupplyCalc(ctx, vm.blockHeight, vm.cstate)
+	}
+
+	return vm.baseCircSupply, nil
 }
 
 func (vm *VM) incrementNonce(addr address.Address) error {
diff --git a/conformance/driver.go b/conformance/driver.go
index 8669089da..c6a20e359 100644
--- a/conformance/driver.go
+++ b/conformance/driver.go
@@ -153,6 +153,14 @@ func (d *Driver) ExecuteTipset(bs blockstore.Blockstore, ds ds.Batching, params
 		results:  []*vm.ApplyRet{},
 	}
 
+	sm.SetVMConstructor(func(ctx context.Context, vmopt *vm.VMOpts) (*vm.VM, error) {
+		vmopt.CircSupplyCalc = func(context.Context, abi.ChainEpoch, *state.StateTree) (abi.TokenAmount, error) {
+			return big.Zero(), nil
+		}
+
+		return vm.NewVM(ctx, vmopt)
+	})
+
 	postcid, receiptsroot, err := tse.ApplyBlocks(context.Background(),
 		sm,
 		params.ParentEpoch,