Merge pull request #539 from ethereum/example_vm_cpp

examples: Convert example VM implementation to C++
ethereum · Nov 3, 2020 · 8a04005 · 8a04005
2 parents 0aeb25b + 8867609
commit 8a04005
Show file tree

Hide file tree

Showing 17 changed files with 633 additions and 289 deletions.
diff --git a/.clang-format b/.clang-format
@@ -5,17 +5,22 @@ AccessModifierOffset: -4
 AlignAfterOpenBracket: Align
 BinPackParameters: false
 BraceWrapping:
-  AfterClass:      true
+  AfterCaseLabel:        true
+  AfterClass:            true
   AfterControlStatement: true
-  AfterEnum:       true
-  AfterFunction:   true
-  AfterNamespace:  true
-  AfterObjCDeclaration: true
-  AfterStruct:     true
-  AfterUnion:      true
-  BeforeCatch:     true
-  BeforeElse:      true
-  SplitEmptyFunction: false
+  AfterEnum:             true
+  AfterFunction:         true
+  AfterNamespace:        true
+  AfterStruct:           true
+  AfterUnion:            true
+  # AfterExternBlock:      true
+  BeforeCatch:           true
+  BeforeElse:            true
+  # BeforeLambdaBody:      true
+  # BeforeWhile:           true
+  SplitEmptyFunction:    false
+  SplitEmptyRecord:      false
+  SplitEmptyNamespace: false
 BreakBeforeBraces: Custom
 BreakBeforeTernaryOperators: false
 ColumnLimit:     100

diff --git a/Doxyfile b/Doxyfile
@@ -102,7 +102,7 @@ WARN_LOGFILE           =
 INPUT                  = \
     include/evmc/ \
     docs/ \
-    examples/example_vm/example_vm.c
+    examples/example_vm/example_vm.cpp
 INPUT_ENCODING         = UTF-8
 FILE_PATTERNS          =
 RECURSIVE              = NO

diff --git a/bindings/go/evmc/evmc_test.go b/bindings/go/evmc/evmc_test.go
@@ -2,7 +2,7 @@
 // Copyright 2018-2020 The EVMC Authors.
 // Licensed under the Apache License, Version 2.0.
 
-//go:generate gcc -shared ../../../examples/example_vm/example_vm.c -I../../../include -o example_vm.so
+//go:generate g++ -shared ../../../examples/example_vm/example_vm.cpp -I../../../include -o example_vm.so
 
 package evmc
 
@@ -41,21 +41,21 @@ func TestLoadConfigure(t *testing.T) {
 	}
 }
 
-func TestExecute(t *testing.T) {
+func TestExecuteEmptyCode(t *testing.T) {
 	vm, _ := Load(modulePath)
 	defer vm.Destroy()
 
 	addr := Address{}
 	h := Hash{}
 	output, gasLeft, err := vm.Execute(nil, Byzantium, Call, false, 1, 999, addr, addr, nil, h, nil, h)
 
-	if bytes.Compare(output, []byte("Welcome to Byzantium!")) != 0 {
-		t.Errorf("execution unexpected output: %s", output)
+	if bytes.Compare(output, []byte("")) != 0 {
+		t.Errorf("execution unexpected output: %x", output)
 	}
-	if gasLeft != 99 {
-		t.Error("execution gas left is incorrect")
+	if gasLeft != 999 {
+		t.Errorf("execution gas left is incorrect: %d", gasLeft)
 	}
-	if err != Failure {
-		t.Error("execution returned unexpected error")
+	if err != nil {
+		t.Errorf("execution returned unexpected error: %v", err)
 	}
 }
diff --git a/bindings/go/evmc/host_test.go b/bindings/go/evmc/host_test.go
@@ -62,49 +62,57 @@ func (host *testHostContext) Call(kind CallKind,
 	return output, gas, Address{}, nil
 }
 
-func TestGetTxContext(t *testing.T) {
+func TestGetBlockNumberFromTxContext(t *testing.T) {
+	// Yul: mstore(0, number()) return(0, msize())
+	code := []byte("\x43\x60\x00\x52\x59\x60\x00\xf3")
+
 	vm, _ := Load(modulePath)
 	defer vm.Destroy()
 
 	host := &testHostContext{}
-	code := []byte("\x43\x60\x00\x52\x59\x60\x00\xf3")
-
 	addr := Address{}
 	h := Hash{}
 	output, gasLeft, err := vm.Execute(host, Byzantium, Call, false, 1, 100, addr, addr, nil, h, code, h)
 
-	if len(output) != 20 {
+	if len(output) != 32 {
 		t.Errorf("unexpected output size: %d", len(output))
 	}
-	if bytes.Compare(output[0:3], []byte("42\x00")) != 0 {
-		t.Errorf("execution unexpected output: %s", output)
+
+	// Should return value 42 (0x2a) as defined in GetTxContext().
+	expectedOutput := []byte("\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x2a")
+	if bytes.Compare(output, expectedOutput) != 0 {
+		t.Errorf("execution unexpected output: %x", output)
 	}
-	if gasLeft != 50 {
+	if gasLeft != 94 {
 		t.Errorf("execution gas left is incorrect: %d", gasLeft)
 	}
 	if err != nil {
-		t.Error("execution returned unexpected error")
+		t.Errorf("execution returned unexpected error: %v", err)
 	}
 }
 
 func TestCall(t *testing.T) {
+	// pseudo-Yul: call(0, 0, 0, 0, 0, 0, 34) return(0, msize())
+	code := []byte("\x60\x22\x60\x00\x80\x80\x80\x80\x80\xf1\x59\x60\x00\xf3")
+
 	vm, _ := Load(modulePath)
 	defer vm.Destroy()
 
 	host := &testHostContext{}
-	code := []byte("\x60\x00\x80\x80\x80\x80\x80\x80\xf1")
-
 	addr := Address{}
 	h := Hash{}
 	output, gasLeft, err := vm.Execute(host, Byzantium, Call, false, 1, 100, addr, addr, nil, h, code, h)
 
+	if len(output) != 34 {
+		t.Errorf("execution unexpected output length: %d", len(output))
+	}
 	if bytes.Compare(output, []byte("output from testHostContext.Call()")) != 0 {
 		t.Errorf("execution unexpected output: %s", output)
 	}
-	if gasLeft != 99 {
+	if gasLeft != 89 {
 		t.Errorf("execution gas left is incorrect: %d", gasLeft)
 	}
 	if err != nil {
-		t.Error("execution returned unexpected error")
+		t.Errorf("execution returned unexpected error: %v", err)
 	}
 }
diff --git a/bindings/java/java/src/test/java/org/ethereum/evmc/EvmcTest.java b/bindings/java/java/src/test/java/org/ethereum/evmc/EvmcTest.java
@@ -70,7 +70,7 @@ void testExecute_returnAddress() throws Exception {
       result.getInt(); // padding
       long gasLeft = result.getLong();
       assert (statusCode == 0);
-      assert (gasLeft == 0);
+      assert (gasLeft == 199994);
     }
   }
 
@@ -100,7 +100,7 @@ void testExecute_counter() throws Exception {
       result.getInt(); // padding
       long gasLeft = result.getLong();
       assert (statusCode == 0);
-      assert (gasLeft == 0);
+      assert (gasLeft == 199994);
     }
   }
 
@@ -130,7 +130,7 @@ void testExecute_returnBlockNumber() throws Exception {
       result.getInt(); // padding
       long gasLeft = result.getLong();
       assert (statusCode == 0);
-      assert (gasLeft == gas / 2);
+      assert (gasLeft == 199994);
     }
   }
 
@@ -162,7 +162,7 @@ void testExecute_saveReturnBlockNumber() throws Exception {
       result.getInt(); // padding
       long gasLeft = result.getLong();
       assert (statusCode == 0);
-      assert (gasLeft == gas / 2);
+      assert (gasLeft == 199991);
     }
   }
 
@@ -201,7 +201,7 @@ void testExecute_makeCall() throws Exception {
       result.getInt(); // padding
       long gasLeft = result.getLong();
       assert (statusCode == 0);
-      assert (gasLeft == 0); // gas - gas / 64);
+      assert (gasLeft == 199992);
     }
   }
 
@@ -229,7 +229,7 @@ void testExecute_EVMC_CREATE() throws Exception {
       result.getInt(); // padding
       long gasLeft = result.getLong();
       assert (statusCode == 0);
-      assert (gasLeft == gas / 10);
+      assert (gasLeft == 199999);
     }
   }
 

diff --git a/circle.yml b/circle.yml
@@ -277,7 +277,7 @@ jobs:
             go get -v $(grep -o 'github.com/ethereum/evmc/v.*' ../../go.mod)@$V
             go mod tidy -v
             go mod graph
-            gcc -shared -I../../include ../../examples/example_vm/example_vm.c -o example-vm.so
+            g++ -shared -I../../include ../../examples/example_vm/example_vm.cpp -o example-vm.so
             go test -v
             go mod graph
 

diff --git a/docs/VM_Guide.md b/docs/VM_Guide.md
@@ -4,7 +4,7 @@
 
 ## An example
 
-You can start with [the example implementation of EVMC VM interface in C](@ref example_vm.c).
+You can start with [the example implementation of EVMC VM interface in C++](@ref example_vm.cpp).
 
 ## VM instance
 

diff --git a/examples/example_vm/CMakeLists.txt b/examples/example_vm/CMakeLists.txt
@@ -2,15 +2,17 @@
 # Copyright 2019-2020 The EVMC Authors.
 # Licensed under the Apache License, Version 2.0.
 
-add_library(example-vm SHARED example_vm.c example_vm.h)
+add_library(example-vm SHARED example_vm.cpp example_vm.h)
 add_library(evmc::example-vm ALIAS example-vm)
+target_compile_features(example-vm PRIVATE cxx_std_11)
 target_link_libraries(example-vm PRIVATE evmc::evmc)
 
-add_library(example-vm-static STATIC example_vm.c example_vm.h)
+add_library(example-vm-static STATIC example_vm.cpp example_vm.h)
 add_library(evmc::example-vm-static ALIAS example-vm-static)
+target_compile_features(example-vm-static PRIVATE cxx_std_11)
 target_link_libraries(example-vm-static PRIVATE evmc::evmc)
 
-set_source_files_properties(example_vm.c PROPERTIES
+set_source_files_properties(example_vm.cpp PROPERTIES
     COMPILE_DEFINITIONS PROJECT_VERSION="${PROJECT_VERSION}")
 
 if(EVMC_INSTALL)