rft: use 256 bit arithmetic for share math (#729)

Author: CheyenneAtapour

snapshots/Hub.Operations.json

@@ -1,9 +1,9 @@
 {
-  "add": "119571",
+  "add": "119161",
   "draw": "112344",
-  "refreshPremium": "100892",
-  "remove: full": "80336",
-  "remove: partial": "86836",
-  "restore: full": "113988",
-  "restore: partial": "119840"
+  "refreshPremium": "100482",
+  "remove: full": "79500",
+  "remove: partial": "86000",
+  "restore: full": "113578",
+  "restore: partial": "119430"
 }

snapshots/Spoke.Getters.json

@@ -1,7 +1,7 @@
 {
   "getUserAccountData: supplies: 0, borrows: 0": "9329",
-  "getUserAccountData: supplies: 1, borrows: 0": "45002",
-  "getUserAccountData: supplies: 2, borrows: 0": "75761",
-  "getUserAccountData: supplies: 2, borrows: 1": "99125",
-  "getUserAccountData: supplies: 2, borrows: 2": "121045"
+  "getUserAccountData: supplies: 1, borrows: 0": "44592",
+  "getUserAccountData: supplies: 2, borrows: 0": "74941",
+  "getUserAccountData: supplies: 2, borrows: 1": "98305",
+  "getUserAccountData: supplies: 2, borrows: 2": "120225"
 }

snapshots/Spoke.Operations.json

@@ -1,28 +1,28 @@
 {
-  "borrow: first": "257886",
-  "borrow: second action, same reserve": "221358",
-  "liquidationCall: full": "328791",
-  "liquidationCall: partial": "352462",
-  "permitReserve + repay (multicall)": "280764",
-  "permitReserve + supply (multicall)": "140631",
-  "permitReserve + supply + enable collateral (multicall)": "174116",
-  "repay: full": "175217",
-  "repay: partial": "239525",
+  "borrow: first": "257066",
+  "borrow: second action, same reserve": "220538",
+  "liquidationCall: full": "326299",
+  "liquidationCall: partial": "349560",
+  "permitReserve + repay (multicall)": "279944",
+  "permitReserve + supply (multicall)": "140221",
+  "permitReserve + supply + enable collateral (multicall)": "173706",
+  "repay: full": "174397",
+  "repay: partial": "238705",
   "setUserPositionManagerWithSig: disable": "38977",
   "setUserPositionManagerWithSig: enable": "63000",
-  "supply + enable collateral (multicall)": "152550",
-  "supply: 0 borrows, collateral disabled": "116444",
-  "supply: 0 borrows, collateral enabled": "119591",
-  "supply: 1 borrow": "119580",
-  "supply: second action, same reserve": "102491",
+  "supply + enable collateral (multicall)": "152140",
+  "supply: 0 borrows, collateral disabled": "116034",
+  "supply: 0 borrows, collateral enabled": "119181",
+  "supply: 1 borrow": "119170",
+  "supply: second action, same reserve": "102081",
   "updateUserDynamicConfig: 1 collateral": "53152",
   "updateUserDynamicConfig: 2 collaterals": "58433",
-  "updateUserRiskPremium: 1 borrow": "143698",
-  "updateUserRiskPremium: 2 borrows": "195417",
+  "updateUserRiskPremium: 1 borrow": "143288",
+  "updateUserRiskPremium: 2 borrows": "195007",
   "usingAsCollateral: 0 borrows, enable": "54026",
-  "usingAsCollateral: 1 borrow, disable": "153924",
+  "usingAsCollateral: 1 borrow, disable": "153514",
   "usingAsCollateral: 1 borrow, enable": "24786",
-  "withdraw: 0 borrows, full": "135122",
-  "withdraw: 0 borrows, partial": "137225",
-  "withdraw: 1 borrow, partial": "254549"
+  "withdraw: 0 borrows, full": "133466",
+  "withdraw: 0 borrows, partial": "135569",
+  "withdraw: 1 borrow, partial": "252483"
 }

src/libraries/math/SharesMath.sol

@@ -2,10 +2,10 @@
 // Copyright (c) 2025 Aave Labs
 pragma solidity ^0.8.0;
 
-import {Math} from 'src/dependencies/openzeppelin/Math.sol';
+import {MathUtils} from 'src/libraries/math/MathUtils.sol';
 
 library SharesMath {
-  using Math for uint256;
+  using MathUtils for uint256;
 
   /// @dev Virtual assets and shares are used to mitigate share manipulation attacks
   uint256 internal constant VIRTUAL_ASSETS = 1e6;
@@ -16,42 +16,30 @@ library SharesMath {
     uint256 totalAssets,
     uint256 totalShares
   ) internal pure returns (uint256) {
-    return
-      assets.mulDiv(
-        totalShares + VIRTUAL_SHARES,
-        totalAssets + VIRTUAL_ASSETS,
-        Math.Rounding.Floor
-      );
+    return assets.mulDivDown(totalShares + VIRTUAL_SHARES, totalAssets + VIRTUAL_ASSETS);
   }
 
   function toAssetsDown(
     uint256 shares,
     uint256 totalAssets,
     uint256 totalShares
   ) internal pure returns (uint256) {
-    return
-      shares.mulDiv(
-        totalAssets + VIRTUAL_ASSETS,
-        totalShares + VIRTUAL_SHARES,
-        Math.Rounding.Floor
-      );
+    return shares.mulDivDown(totalAssets + VIRTUAL_ASSETS, totalShares + VIRTUAL_SHARES);
   }
 
   function toSharesUp(
     uint256 assets,
     uint256 totalAssets,
     uint256 totalShares
   ) internal pure returns (uint256) {
-    return
-      assets.mulDiv(totalShares + VIRTUAL_SHARES, totalAssets + VIRTUAL_ASSETS, Math.Rounding.Ceil);
+    return assets.mulDivUp(totalShares + VIRTUAL_SHARES, totalAssets + VIRTUAL_ASSETS);
   }
 
   function toAssetsUp(
     uint256 shares,
     uint256 totalAssets,
     uint256 totalShares
   ) internal pure returns (uint256) {
-    return
-      shares.mulDiv(totalAssets + VIRTUAL_ASSETS, totalShares + VIRTUAL_SHARES, Math.Rounding.Ceil);
+    return shares.mulDivUp(totalAssets + VIRTUAL_ASSETS, totalShares + VIRTUAL_SHARES);
   }
 }