report target error if llvm-target not set

internal/crosscompile/crosscompile.go

@@ -422,6 +422,11 @@ func useTarget(targetName string) (export Export, err error) {
 		return export, fmt.Errorf("failed to resolve target %s: %w", targetName, err)
 	}
 
+	target := config.LLVMTarget
+	if target == "" {
+		return export, fmt.Errorf("target '%s' does not have a valid LLVM target triple", targetName)
+	}
+
 	// Check for ESP Clang support for target-based builds
 	clangRoot, err := getESPClangRoot()
 	if err != nil {
@@ -445,11 +450,6 @@ func useTarget(targetName string) (export Export, err error) {
 	var ccflags []string
 	var ldflags []string
 
-	target := config.LLVMTarget
-	if target == "" {
-		target = llvm.GetTargetTriple(config.GOOS, config.GOARCH)
-	}
-
 	cflags := []string{"-Wno-override-module"}
 	if config.LLVMTarget != "" {
 		cflags = append(cflags, "--target="+config.LLVMTarget)

internal/crosscompile/crosscompile_test.go

@@ -193,7 +193,7 @@ func TestUseTarget(t *testing.T) {
 		{
 			name:        "Cortex-M Target",
 			targetName:  "cortex-m",
-			expectError: false,
+			expectError: true,
 			expectLLVM:  "",
 			expectCPU:   "",
 		},