mocked_host: create account in set_storage if non-existent

CMakeLists.txt

@@ -19,7 +19,6 @@ include(CableCompilerSettings)
 include(CablePackage)
 include(CMakeDependentOption)
 include(CMakePackageConfigHelpers)
-include(GNUInstallDirs)
 
 option(EVMC_JAVA "Enable building Java Native Interface (JNI) bindings" OFF)
 
@@ -47,6 +46,8 @@ cable_set_build_type(DEFAULT Release CONFIGURATION_TYPES Debug Release)
 project(evmc)
 set(PROJECT_VERSION 8.1.0-alpha.0)
 
+include(GNUInstallDirs)  # Must be included after any language is enabled.
+
 cable_configure_compiler(NO_STACK_PROTECTION)
 if(CABLE_COMPILER_GNULIKE)
     # TODO: Resolve issues or remove "result optional storage" and enable -Wcast-align.

include/evmc/mocked_host.hpp

@@ -185,11 +185,12 @@ class MockedHost : public Host
                                     const bytes32& value) noexcept override
     {
         record_account_access(addr);
-        const auto it = accounts.find(addr);
-        if (it == accounts.end())
-            return EVMC_STORAGE_UNCHANGED;
 
-        auto& old = it->second.storage[key];
+        // Get the reference to the old value.
+        // This will create the account in case it was not present.
+        // This is convenient for unit testing and standalone EVM execution to preserve the
+        // storage values after the execution terminates.
+        auto& old = accounts[addr].storage[key];
 
         // Follow https://eips.ethereum.org/EIPS/eip-1283 specification.
         // WARNING! This is not complete implementation as refund is not handled here.

test/unittests/mocked_host_test.cpp

@@ -34,8 +34,11 @@ TEST(mocked_host, storage)
     EXPECT_EQ(chost.get_storage(addr1, {}), evmc::bytes32{});
     EXPECT_EQ(chost.get_storage(addr2, {}), evmc::bytes32{});
 
-    // Set storage on non-existing account has no effect.
-    EXPECT_EQ(host.set_storage(addr2, val1, val2), EVMC_STORAGE_UNCHANGED);
+    // Set storage on non-existing account creates the account.
+    EXPECT_EQ(host.set_storage(addr1, val1, val2), EVMC_STORAGE_ADDED);
+    EXPECT_EQ(chost.accounts.count(addr1), 1u);
+    EXPECT_EQ(host.accounts[addr1].storage.count(val1), 1u);
+    EXPECT_EQ(host.accounts[addr1].storage[val1].value, val2);
 
     auto& acc2 = host.accounts[addr2];
     EXPECT_EQ(chost.get_storage(addr2, val1), evmc::bytes32{});

test/unittests/tool_commands_test.cpp

@@ -117,3 +117,17 @@ TEST(tool_commands, create_failure_stack_underflow)
               "Creating and executing on Petersburg with 0 gas limit\n"
               "Contract creation failed: undefined instruction\n");
 }
+
+TEST(tool_commands, create_preserve_storage)
+{
+    // Contract: sload(0) mstore(0) return(31, 1)  6000 54 6000 52 6001 601f f3
+    // Create:   sstore(0, 0xbb) mstore(0, "6000546000526001601ff3") return(21, 11)
+    auto vm = evmc::VM{evmc_create_example_vm()};
+    std::ostringstream out;
+
+    const auto exit_code =
+        cmd::run(vm, EVMC_BERLIN, 200, "60bb 6000 55 6a6000546000526001601ff3 6000 52 600b 6015 f3",
+                 "", true, out);
+    EXPECT_EQ(exit_code, 0);
+    EXPECT_EQ(out.str(), out_pattern("Berlin", 200, "success", 7, "bb", true));
+}