From 03feb369441929581ab6bf07794ee4852e36655e Mon Sep 17 00:00:00 2001
From: mriise <me@mriise.net>
Date: Thu, 12 Jan 2023 17:30:35 -0800
Subject: [PATCH] add precompile test contract, use it for actor_type

---
 actors/evm/tests/precompile.rs | 140 +++++++++++++++++++++++++--------
 1 file changed, 109 insertions(+), 31 deletions(-)

diff --git a/actors/evm/tests/precompile.rs b/actors/evm/tests/precompile.rs
index 8f2031855e..dfc5a9cd1d 100644
--- a/actors/evm/tests/precompile.rs
+++ b/actors/evm/tests/precompile.rs
@@ -1,5 +1,7 @@
 mod asm;
 
+use std::fmt::Debug;
+
 use evm::interpreter::{address::EthAddress, U256};
 use fil_actor_evm as evm;
 use fil_actors_runtime::test_utils::{
@@ -63,58 +65,126 @@ fn test_precompile_hash() {
     );
 }
 
-#[test]
-fn test_native_actor_type() {
-    let bytecode = {
+struct PrecompileTest {
+    pub expected_return: Vec<u8>,
+    pub expected_exit_code: PrecompileExit,
+    pub precompile_number: u8,
+    pub output_size: u8,
+    pub input: Vec<u8>,
+    pub gas_avaliable: u64,
+}
+
+#[repr(u8)]
+enum PrecompileExit {
+    Reverted = 0,
+    Success = 1,
+}
+
+impl Debug for PrecompileTest {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("PrecompileTest")
+            .field("expected_return", &hex::encode(&self.expected_return))
+            .field("expected_exit_code", &(self.expected_exit_code as u8))
+            .field("precompile_number", &format!("{:x}", self.precompile_number))
+            .field("output_size", &self.output_size)
+            .field("precompile_number", &self.output_size)
+            .field("input", &hex::encode(&self.input))
+            .field("gas_avaliable", &self.gas_avaliable)
+            .finish()
+    }
+}
+
+impl PrecompileTest {
+    fn run_test(&self, rt: &mut MockRuntime) {
+        rt.expect_gas_available(self.gas_avaliable);
+        log::trace!("{:#?}", &self);
+        // first byte is precompile number, second is output buffer size, rest is input to precompile
+        let result = util::invoke_contract(
+            rt,
+            &[vec![self.precompile_number, self.output_size], self.input.clone()].concat(),
+        );
+        log::trace!("returned: {:?}", hex::encode(&result));
+        rt.verify();
+        assert_eq!(self.expected_exit_code as u8, result[0]);
+        assert_eq!(&self.expected_return, &result[1..]);
+        rt.reset();
+    }
+
+    fn test_runner_bytecode() -> Vec<u8> {
         let init = "";
         let body = r#"
-    
-# get call payload size
-calldatasize
 # store payload to mem 0x00
-push1 0x00
-push1 0x00
+calldatasize
+push1 0x00 # input offset
+push1 0x00 # dst offset
 calldatacopy
 
 # out size
+push1 0x01 # second byte of input
+mload
+push1 0x08
+push1 0x1f
+mul # 31*8 bits
+shr
+
 # out off
-push1 0x20
-push1 0xA0
+push2 0xA0
 
 # in size
-# in off
+push1 0x02
 calldatasize
-push1 0x00
+sub
+# in off
+push1 0x02
 
 # value
 push1 0x00
 
-# dst (get_actor_type precompile)
-push20 0xfe00000000000000000000000000000000000004
+# precompile address
+push20 0xfe00000000000000000000000000000000000000
+
+push1 0x00 # first byte of input is index
+mload
+push1 0x08
+push1 0x1f
+mul # 31*8 bits 
+shr
+
+add
 
 # gas
 push1 0x00
 
 call
 
-# copy result to mem 0x00 (overwrites input data)
+# write exit code memory
+push1 0x00 # offset
+mstore8
+
+# write precompile return to memory
 returndatasize
-push1 0x00
-push1 0x00
+push1 0x00 # input offset
+push1 0x01 # dst offset
 returndatacopy
 
-# return
+# size
 returndatasize
+push1 0x01
+add
+# offset
 push1 0x00
 return
 "#;
 
-        asm::new_contract("native_actor_type", init, body).unwrap()
-    };
+        asm::new_contract("precompile_tester", init, body).unwrap()
+    }
+}
 
+#[test]
+fn test_native_actor_type() {
     use evm::interpreter::precompiles::NativeType;
 
-    let mut rt = util::construct_and_verify(bytecode);
+    let mut rt = util::construct_and_verify(PrecompileTest::test_runner_bytecode());
 
     // 0x88 is an EVM actor
     let evm_target = FILAddress::new_id(0x88);
@@ -141,11 +211,15 @@ return
     rt.set_address_actor_type(other_target, *MULTISIG_ACTOR_CODE_ID);
 
     fn test_type(rt: &mut MockRuntime, id: FILAddress, expected: NativeType) {
-        rt.expect_gas_available(10_000_000_000u64);
-        let result = util::invoke_contract(rt, &id_to_vec(&id));
-        rt.verify();
-        assert_eq!(&U256::from(expected as u32).to_bytes(), result.as_slice());
-        rt.reset();
+        let test = PrecompileTest {
+            precompile_number: 4,
+            input: id_to_vec(&id),
+            output_size: 32,
+            expected_exit_code: PrecompileExit::Success,
+            expected_return: U256::from(expected as u32).to_bytes().to_vec(),
+            gas_avaliable: 10_000_000_000,
+        };
+        test.run_test(rt);
     }
 
     test_type(&mut rt, evm_target, NativeType::EVMContract);
@@ -157,11 +231,15 @@ return
     test_type(&mut rt, FILAddress::new_id(10101), NativeType::NonExistent);
 
     // invalid format address
-    rt.expect_gas_available(10_000_000_000u64);
-    let result = util::invoke_contract(&mut rt, &[0xff; 64]);
-    rt.verify();
-    assert!(result.is_empty());
-    rt.reset();
+    let test = PrecompileTest {
+        precompile_number: 4,
+        input: vec![0xff; 64],
+        output_size: 32,
+        expected_exit_code: PrecompileExit::Reverted,
+        expected_return: vec![],
+        gas_avaliable: 10_000_000_000,
+    };
+    test.run_test(&mut rt);
 }
 
 fn resolve_address_contract() -> Vec<u8> {