compiler: add tests for error messages

The test is currently empty, but will be used in the next commit.

2 files changed, 86 insertions, 43 deletions

diff --git a/compiler/compiler_test.go b/compiler/compiler_test.go
index 74e213dc6..6b5fbe13c 100644
--- a/compiler/compiler_test.go
+++ b/compiler/compiler_test.go
@@ -70,52 +70,11 @@ func TestCompiler(t *testing.T) {
 			options := &compileopts.Options{
 				Target: targetString,
 			}
-			target, err := compileopts.LoadTarget(options)
-			if err != nil {
-				t.Fatal("failed to load target:", err)
-			}
 			if tc.scheduler != "" {
 				options.Scheduler = tc.scheduler
 			}
-			config := &compileopts.Config{
-				Options: options,
-				Target:  target,
-			}
-			compilerConfig := &Config{
-				Triple:             config.Triple(),
-				Features:           config.Features(),
-				ABI:                config.ABI(),
-				GOOS:               config.GOOS(),
-				GOARCH:             config.GOARCH(),
-				CodeModel:          config.CodeModel(),
-				RelocationModel:    config.RelocationModel(),
-				Scheduler:          config.Scheduler(),
-				AutomaticStackSize: config.AutomaticStackSize(),
-				DefaultStackSize:   config.StackSize(),
-				NeedsStackObjects:  config.NeedsStackObjects(),
-			}
-			machine, err := NewTargetMachine(compilerConfig)
-			if err != nil {
-				t.Fatal("failed to create target machine:", err)
-			}
-			defer machine.Dispose()
-
-			// Load entire program AST into memory.
-			lprogram, err := loader.Load(config, "./testdata/"+tc.file, config.ClangHeaders, types.Config{
-				Sizes: Sizes(machine),
-			})
-			if err != nil {
-				t.Fatal("failed to create target machine:", err)
-			}
-			err = lprogram.Parse()
-			if err != nil {
-				t.Fatalf("could not parse test case %s: %s", tc.file, err)
-			}
 
-			// Compile AST to IR.
-			program := lprogram.LoadSSA()
-			pkg := lprogram.MainPkg()
-			mod, errs := CompilePackage(tc.file, pkg, program.Package(pkg.Pkg), machine, compilerConfig, false)
+			mod, errs := testCompilePackage(t, options, tc.file)
 			if errs != nil {
 				for _, err := range errs {
 					t.Error(err)
@@ -123,7 +82,7 @@ func TestCompiler(t *testing.T) {
 				return
 			}
 
-			err = llvm.VerifyModule(mod, llvm.PrintMessageAction)
+			err := llvm.VerifyModule(mod, llvm.PrintMessageAction)
 			if err != nil {
 				t.Error(err)
 			}
@@ -216,3 +175,86 @@ func filterIrrelevantIRLines(lines []string) []string {
 	}
 	return out
 }
+
+func TestCompilerErrors(t *testing.T) {
+	t.Parallel()
+
+	// Read expected errors from the test file.
+	var expectedErrors []string
+	errorsFile, err := os.ReadFile("testdata/errors.go")
+	if err != nil {
+		t.Error(err)
+	}
+	errorsFileString := strings.ReplaceAll(string(errorsFile), "\r\n", "\n")
+	for _, line := range strings.Split(errorsFileString, "\n") {
+		if strings.HasPrefix(line, "// ERROR: ") {
+			expectedErrors = append(expectedErrors, strings.TrimPrefix(line, "// ERROR: "))
+		}
+	}
+
+	// Compile the Go file with errors.
+	options := &compileopts.Options{
+		Target: "wasm",
+	}
+	_, errs := testCompilePackage(t, options, "errors.go")
+
+	// Check whether the actual errors match the expected errors.
+	expectedErrorsIdx := 0
+	for _, err := range errs {
+		err := err.(types.Error)
+		position := err.Fset.Position(err.Pos)
+		position.Filename = "errors.go" // don't use a full path
+		if expectedErrorsIdx >= len(expectedErrors) || expectedErrors[expectedErrorsIdx] != err.Msg {
+			t.Errorf("unexpected compiler error: %s: %s", position.String(), err.Msg)
+			continue
+		}
+		expectedErrorsIdx++
+	}
+}
+
+// Build a package given a number of compiler options and a file.
+func testCompilePackage(t *testing.T, options *compileopts.Options, file string) (llvm.Module, []error) {
+	target, err := compileopts.LoadTarget(options)
+	if err != nil {
+		t.Fatal("failed to load target:", err)
+	}
+	config := &compileopts.Config{
+		Options: options,
+		Target:  target,
+	}
+	compilerConfig := &Config{
+		Triple:             config.Triple(),
+		Features:           config.Features(),
+		ABI:                config.ABI(),
+		GOOS:               config.GOOS(),
+		GOARCH:             config.GOARCH(),
+		CodeModel:          config.CodeModel(),
+		RelocationModel:    config.RelocationModel(),
+		Scheduler:          config.Scheduler(),
+		AutomaticStackSize: config.AutomaticStackSize(),
+		DefaultStackSize:   config.StackSize(),
+		NeedsStackObjects:  config.NeedsStackObjects(),
+	}
+	machine, err := NewTargetMachine(compilerConfig)
+	if err != nil {
+		t.Fatal("failed to create target machine:", err)
+	}
+	defer machine.Dispose()
+
+	// Load entire program AST into memory.
+	lprogram, err := loader.Load(config, "./testdata/"+file, config.ClangHeaders, types.Config{
+		Sizes: Sizes(machine),
+	})
+	if err != nil {
+		t.Fatal("failed to create target machine:", err)
+	}
+	err = lprogram.Parse()
+	if err != nil {
+		t.Fatalf("could not parse test case %s: %s", file, err)
+	}
+
+	// Compile AST to IR.
+	program := lprogram.LoadSSA()
+	pkg := lprogram.MainPkg()
+	return CompilePackage(file, pkg, program.Package(pkg.Pkg), machine, compilerConfig, false)
+}
diff --git a/compiler/testdata/errors.go b/compiler/testdata/errors.go
new file mode 100644
index 000000000..06ab7d0f9
--- /dev/null
+++ b/compiler/testdata/errors.go
@@ -0,0 +1 @@
+package main