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-rw-r--r--packages/sol-trace-based-tools-common/src/revert_trace.ts95
1 files changed, 95 insertions, 0 deletions
diff --git a/packages/sol-trace-based-tools-common/src/revert_trace.ts b/packages/sol-trace-based-tools-common/src/revert_trace.ts
new file mode 100644
index 000000000..4d474120c
--- /dev/null
+++ b/packages/sol-trace-based-tools-common/src/revert_trace.ts
@@ -0,0 +1,95 @@
+import { logUtils } from '@0x/utils';
+import { OpCode, StructLog } from 'ethereum-types';
+
+import * as _ from 'lodash';
+
+import { EvmCallStack } from './types';
+import { utils } from './utils';
+
+/**
+ * Converts linear trace to a call stack by following calls and returns
+ * @param structLogs Linear trace
+ * @param startAddress The address of initial context
+ */
+export function getRevertTrace(structLogs: StructLog[], startAddress: string): EvmCallStack {
+ const evmCallStack: EvmCallStack = [];
+ const addressStack = [startAddress];
+ if (_.isEmpty(structLogs)) {
+ return [];
+ }
+ const normalizedStructLogs = utils.normalizeStructLogs(structLogs);
+ // tslint:disable-next-line:prefer-for-of
+ for (let i = 0; i < normalizedStructLogs.length; i++) {
+ const structLog = normalizedStructLogs[i];
+ if (structLog.depth !== addressStack.length - 1) {
+ throw new Error("Malformed trace. Trace depth doesn't match call stack depth");
+ }
+ // After that check we have a guarantee that call stack is never empty
+ // If it would: callStack.length - 1 === structLog.depth === -1
+ // That means that we can always safely pop from it
+
+ if (utils.isCallLike(structLog.op)) {
+ const currentAddress = _.last(addressStack) as string;
+ const jumpAddressOffset = 1;
+ const newAddress = utils.getAddressFromStackEntry(
+ structLog.stack[structLog.stack.length - jumpAddressOffset - 1],
+ );
+
+ // Sometimes calls don't change the execution context (current address). When we do a transfer to an
+ // externally owned account - it does the call and immediately returns because there is no fallback
+ // function. We manually check if the call depth had changed to handle that case.
+ const nextStructLog = normalizedStructLogs[i + 1];
+ if (nextStructLog.depth !== structLog.depth) {
+ addressStack.push(newAddress);
+ evmCallStack.push({
+ address: currentAddress,
+ structLog,
+ });
+ }
+ } else if (utils.isEndOpcode(structLog.op) && structLog.op !== OpCode.Revert) {
+ // Just like with calls, sometimes returns/stops don't change the execution context (current address).
+ const nextStructLog = normalizedStructLogs[i + 1];
+ if (_.isUndefined(nextStructLog) || nextStructLog.depth !== structLog.depth) {
+ evmCallStack.pop();
+ addressStack.pop();
+ }
+ if (structLog.op === OpCode.SelfDestruct) {
+ // After contract execution, we look at all sub-calls to external contracts, and for each one, fetch
+ // the bytecode and compute the coverage for the call. If the contract is destroyed with a call
+ // to `selfdestruct`, we are unable to fetch it's bytecode and compute coverage.
+ // TODO: Refactor this logic to fetch the sub-called contract bytecode before the selfdestruct is called
+ // in order to handle this edge-case.
+ logUtils.warn(
+ "Detected a selfdestruct. We currently do not support that scenario. We'll just skip the trace part for a destructed contract",
+ );
+ }
+ } else if (structLog.op === OpCode.Revert) {
+ evmCallStack.push({
+ address: _.last(addressStack) as string,
+ structLog,
+ });
+ return evmCallStack;
+ } else if (structLog.op === OpCode.Create) {
+ // TODO: Extract the new contract address from the stack and handle that scenario
+ logUtils.warn(
+ "Detected a contract created from within another contract. We currently do not support that scenario. We'll just skip that trace",
+ );
+ return [];
+ } else {
+ if (structLog !== _.last(normalizedStructLogs)) {
+ const nextStructLog = normalizedStructLogs[i + 1];
+ if (nextStructLog.depth === structLog.depth) {
+ continue;
+ } else if (nextStructLog.depth === structLog.depth - 1) {
+ addressStack.pop();
+ } else {
+ throw new Error('Malformed trace. Unexpected call depth change');
+ }
+ }
+ }
+ }
+ if (evmCallStack.length !== 0) {
+ logUtils.warn('Malformed trace. Call stack non empty at the end. (probably out of gas)');
+ }
+ return [];
+}