cmd/land: add struct test

cmd/land/process_test.go

@@ -1,8 +1,12 @@
 package main
 
 import (
+	"bytes"
+	"encoding/binary"
 	"os"
 	"testing"
+
+	"github.com/kr/pretty"
 )
 
 func testWasmFile(t *testing.T, fname string) *Process {
@@ -77,3 +81,33 @@ func TestFileOps(t *testing.T) {
 		t.Fatalf("wanted \"Hello, world\", got: %q", string(data))
 	}
 }
+
+func TestArbint(t *testing.T) {
+	p := testWasmFile(t, "./testdata/arbint.wasm")
+	pretty.Println(p.vm.Memory()[0x200:0x204])
+}
+
+type structFromC struct {
+	Bar int32
+	Baz int32
+}
+
+func TestStruct(t *testing.T) {
+	p := testWasmFile(t, "./testdata/struct.wasm")
+	pretty.Println(p.vm.Memory()[0x200:0x208])
+
+	foo := structFromC{}
+	if err := binary.Read(bytes.NewReader(p.vm.Memory()[0x200:0x208]), binary.LittleEndian, &foo); err != nil {
+		t.Fatalf("can't read memory as the struct: %v", err)
+	}
+
+	t.Logf("%#v", foo)
+
+	if foo.Bar != 31337 {
+		t.Fatalf("wanted foo.bar to be 31337, got: %d", foo.Bar)
+	}
+
+	if foo.Baz != 255 {
+		t.Fatalf("wanted foo.baz to be 255, got: %d", foo.Baz)
+	}
+}

cmd/land/testdata/Tupfile

@@ -0,0 +1,7 @@
+include_rules
+
+CFLAGS += --target=wasm32-unknown-unknown-wasm
+CFLAGS += --sysroot=~/code/wasmception/sysroot/
+CFLAGS += -O0 -nostartfiles -Wl,--no-entry -nostdlib
+
+: foreach *.c |>  ~/code/wasmception/dist/bin/clang $(CFLAGS) %f -o %o |> %B.wasm

cmd/land/testdata/arbint.c

@@ -0,0 +1,7 @@
+void _start() {}
+
+__attribute__ ((visibility ("default")))
+int main() {
+  *(int*)0x200 = 255;
+  return 0;
+}

cmd/land/testdata/struct.c

@@ -0,0 +1,16 @@
+struct Foo {
+  int bar;
+  int baz;
+};
+
+__attribute__ ((visibility ("default")))
+int main() {
+  struct Foo foo;
+
+  foo.bar = 31337;
+  foo.baz = 255;
+
+  *(struct Foo*)0x200 = foo;
+
+  return 0;
+}