Test basic DWARF generation (#931)

* Add obj generation with debug info
* Add simple transform check

tests/debug/simulate.rs

@@ -0,0 +1,55 @@
+use super::dump::{get_dwarfdump, DwarfDumpSection};
+use super::obj::compile_cranelift;
+use anyhow::{format_err, Result};
+use filecheck::{CheckerBuilder, NO_VARIABLES};
+use tempfile::NamedTempFile;
+use wat::parse_str;
+
+#[allow(dead_code)]
+fn check_wat(wat: &str) -> Result<()> {
+    let wasm = parse_str(wat)?;
+    let obj_file = NamedTempFile::new()?;
+    let obj_path = obj_file.path().to_str().unwrap();
+    compile_cranelift(&wasm, None, obj_path)?;
+    let dump = get_dwarfdump(obj_path, DwarfDumpSection::DebugInfo)?;
+    let mut builder = CheckerBuilder::new();
+    builder
+        .text(wat)
+        .map_err(|e| format_err!("unable to build checker: {:?}", e))?;
+    let checker = builder.finish();
+    let check = checker
+        .explain(&dump, NO_VARIABLES)
+        .map_err(|e| format_err!("{:?}", e))?;
+    assert!(check.0, "didn't pass check {}", check.1);
+    Ok(())
+}
+
+#[test]
+#[cfg(all(
+    any(target_os = "linux", target_os = "macos"),
+    target_pointer_width = "64"
+))]
+fn test_debug_dwarf_simulate_simple_x86_64() -> Result<()> {
+    check_wat(
+        r#"
+;; check: DW_TAG_compile_unit 
+(module
+;; check: DW_TAG_subprogram 
+;; check: DW_AT_name	("wasm-function[0]")
+;; check:   DW_TAG_formal_parameter
+;; check:     DW_AT_name	("var0")
+;; check:     DW_AT_type
+;; sameln:	            "i32"
+;; check:   DW_TAG_variable
+;; check:     DW_AT_name	("var1")
+;; check:     DW_AT_type
+;; sameln:	            "i32"
+    (func (param i32) (result i32)
+        (local i32)
+        local.get 0
+        local.set 1
+        local.get 1
+    )
+)"#,
+    )
+}