wasm: override dlmalloc heap implementation from wasi-libc

These two heaps conflict with each other, so that if any function uses
the dlmalloc heap implementation it will eventually result in memory
corruption.

This commit fixes this by implementing all heap-related functions. This
overrides the functions that are implemented in wasi-libc. That's why
all of them are implemented (even if they just panic): to make sure no
program accidentally uses the wrong one.

main_test.go

@@ -125,7 +125,7 @@ func TestCompiler(t *testing.T) {
 		// Test with few optimizations enabled (no inlining, etc).
 		t.Run("opt=1", func(t *testing.T) {
 			t.Parallel()
-			runTestWithConfig("stdlib.go", "", t, &compileopts.Options{
+			runTestWithConfig("stdlib.go", "", t, compileopts.Options{
 				Opt: "1",
 			}, nil, nil)
 		})
@@ -134,15 +134,14 @@ func TestCompiler(t *testing.T) {
 		// TODO: fix this for stdlib.go, which currently fails.
 		t.Run("opt=0", func(t *testing.T) {
 			t.Parallel()
-			runTestWithConfig("print.go", "", t, &compileopts.Options{
+			runTestWithConfig("print.go", "", t, compileopts.Options{
 				Opt: "0",
 			}, nil, nil)
 		})
 
 		t.Run("ldflags", func(t *testing.T) {
 			t.Parallel()
-			runTestWithConfig("ldflags.go", "", t, &compileopts.Options{
-				Opt: "z",
+			runTestWithConfig("ldflags.go", "", t, compileopts.Options{
 				GlobalValues: map[string]map[string]string{
 					"main": {
 						"someGlobal": "foobar",
@@ -188,20 +187,20 @@ func runBuild(src, out string, opts *compileopts.Options) error {
 }
 
 func runTest(name, target string, t *testing.T, cmdArgs, environmentVars []string) {
-	options := &compileopts.Options{
-		Target:     target,
-		Opt:        "z",
-		PrintIR:    false,
-		DumpSSA:    false,
-		VerifyIR:   true,
-		Debug:      true,
-		PrintSizes: "",
-		WasmAbi:    "",
+	options := compileopts.Options{
+		Target: target,
 	}
 	runTestWithConfig(name, target, t, options, cmdArgs, environmentVars)
 }
 
-func runTestWithConfig(name, target string, t *testing.T, options *compileopts.Options, cmdArgs, environmentVars []string) {
+func runTestWithConfig(name, target string, t *testing.T, options compileopts.Options, cmdArgs, environmentVars []string) {
+	// Set default config.
+	options.Debug = true
+	options.VerifyIR = true
+	if options.Opt == "" {
+		options.Opt = "z"
+	}
+
 	// Get the expected output for this test.
 	// Note: not using filepath.Join as it strips the path separator at the end
 	// of the path.
@@ -230,7 +229,7 @@ func runTestWithConfig(name, target string, t *testing.T, options *compileopts.O
 
 	// Build the test binary.
 	binary := filepath.Join(tmpdir, "test")
-	err = runBuild("./"+path, binary, options)
+	err = runBuild("./"+path, binary, &options)
 	if err != nil {
 		printCompilerError(t.Log, err)
 		t.Fail()