Iter 4c: IR-Snapshot-Tests als Codegen-Regressions-Schutz

Vier Snapshots in crates/ail/tests/snapshots/ (sum, max3, hello, list)
sichern den erzeugten LLVM-IR. Test-Helper normalisiert target triple
und trailing whitespace, sonst byte-für-byte-Vergleich. Update via
UPDATE_SNAPSHOTS=1 cargo test ir_snapshot_. Mismatch erzeugt eine
.actual-Datei mit dem aktuellen Output für Diff-Inspektion.
This commit is contained in:
2026-05-07 11:14:41 +02:00
parent c652b12582
commit 74a20055c3
6 changed files with 344 additions and 0 deletions
+2
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@@ -1,3 +1,5 @@
/target
*.ll.o
/build
crates/ail/tests/snapshots/*.actual
crates/ail/tests/snapshots/*.ll.actual
+153
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//! IR-Snapshot-Tests: schützen die Codegen-Pipeline vor unbeabsichtigten
//! Veränderungen am LLVM-IR. Snapshots in tests/snapshots/. Update mit
//! UPDATE_SNAPSHOTS=1 cargo test ir_snapshot_.
use std::path::{Path, PathBuf};
use std::process::Command;
fn ail_bin() -> &'static str {
env!("CARGO_BIN_EXE_ail")
}
/// Normalisiert IR-Text für Plattform-Stabilität:
/// - `target triple = "..."` -> `target triple = "<NORMALIZED>"`
/// - trailing whitespace pro Zeile entfernen
/// - LF-Zeilenenden, Datei endet mit genau einem `\n`
fn normalize(ir: &str) -> String {
let mut out = String::with_capacity(ir.len());
for line in ir.split('\n') {
let line = line.strip_suffix('\r').unwrap_or(line);
let trimmed = line.trim_end();
if let Some(rest) = trimmed.strip_prefix("target triple = ") {
// rest ist `"..."` (mit Anführungszeichen) — komplett normalisieren.
let _ = rest;
out.push_str("target triple = \"<NORMALIZED>\"");
} else {
out.push_str(trimmed);
}
out.push('\n');
}
// split('\n') erzeugt nach einem trailing `\n` ein leeres letztes Stück,
// das oben mit `\n` abgeschlossen wurde. Dadurch enthält `out` typischerweise
// genau ein abschließendes `\n`. Doppelte `\n\n` am Ende reduzieren.
while out.ends_with("\n\n") {
out.pop();
}
if !out.ends_with('\n') {
out.push('\n');
}
out
}
fn snapshots_dir() -> PathBuf {
let manifest_dir = env!("CARGO_MANIFEST_DIR");
Path::new(manifest_dir).join("tests").join("snapshots")
}
fn examples_dir() -> PathBuf {
let manifest_dir = env!("CARGO_MANIFEST_DIR");
Path::new(manifest_dir)
.parent()
.unwrap()
.parent()
.unwrap()
.join("examples")
}
fn first_diff_line(a: &str, b: &str) -> Option<(usize, String, String)> {
let mut la = a.lines();
let mut lb = b.lines();
let mut idx = 1usize;
loop {
match (la.next(), lb.next()) {
(Some(x), Some(y)) => {
if x != y {
return Some((idx, x.to_string(), y.to_string()));
}
}
(Some(x), None) => return Some((idx, x.to_string(), String::from("<EOF>"))),
(None, Some(y)) => return Some((idx, String::from("<EOF>"), y.to_string())),
(None, None) => return None,
}
idx += 1;
}
}
fn check_ir_snapshot(example: &str, snapshot_name: &str) {
let example_path = examples_dir().join(example);
assert!(
example_path.exists(),
"example missing: {}",
example_path.display()
);
let tmpdir = std::env::temp_dir().join(format!(
"ailang_ir_snapshot_{}_{}",
snapshot_name.replace('.', "_"),
std::process::id()
));
std::fs::create_dir_all(&tmpdir).unwrap();
let out_ll = tmpdir.join(format!("{snapshot_name}.tmp.ll"));
let status = Command::new(ail_bin())
.args(["emit-ir", example_path.to_str().unwrap(), "-o"])
.arg(&out_ll)
.status()
.expect("ail emit-ir failed to run");
assert!(status.success(), "ail emit-ir failed for {example}");
let actual_raw = std::fs::read_to_string(&out_ll).expect("read emitted IR");
let actual = normalize(&actual_raw);
let snapshot_path = snapshots_dir().join(snapshot_name);
if std::env::var_os("UPDATE_SNAPSHOTS").is_some() {
std::fs::create_dir_all(snapshots_dir()).unwrap();
std::fs::write(&snapshot_path, &actual).expect("write snapshot");
eprintln!("updated snapshot: {}", snapshot_path.display());
return;
}
let expected_raw = std::fs::read_to_string(&snapshot_path).unwrap_or_else(|e| {
panic!(
"missing snapshot {}: {e}\nrun with UPDATE_SNAPSHOTS=1 to create it",
snapshot_path.display()
)
});
let expected = normalize(&expected_raw);
if actual != expected {
let actual_path = snapshot_path.with_extension("ll.actual");
std::fs::write(&actual_path, &actual).expect("write .actual");
let diff_msg = match first_diff_line(&expected, &actual) {
Some((line, want, got)) => format!(
"first diff at line {line}:\n expected: {want}\n actual: {got}",
),
None => "files differ but no line-level diff found (whitespace?)".to_string(),
};
panic!(
"IR snapshot mismatch for {example}\n{diff_msg}\nactual written to: {}\nrun UPDATE_SNAPSHOTS=1 cargo test ir_snapshot_ to refresh.",
actual_path.display()
);
}
}
#[test]
fn ir_snapshot_sum() {
check_ir_snapshot("sum.ail.json", "sum.ll");
}
#[test]
fn ir_snapshot_max3() {
check_ir_snapshot("max3.ail.json", "max3.ll");
}
#[test]
fn ir_snapshot_hello() {
check_ir_snapshot("hello.ail.json", "hello.ll");
}
#[test]
fn ir_snapshot_list() {
check_ir_snapshot("list.ail.json", "list.ll");
}
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; AILang generated module: hello
source_filename = "hello.ail"
target triple = "<NORMALIZED>"
@.str_str_0 = private unnamed_addr constant [15 x i8] c"Hallo, AILang.\00", align 1
declare i32 @printf(ptr, ...)
declare i32 @puts(ptr)
declare ptr @malloc(i64)
define i8 @ail_main() {
entry:
call i32 @puts(ptr @.str_str_0)
ret i8 0
}
define i32 @main() {
call i8 @ail_main()
ret i32 0
}
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; AILang generated module: list
source_filename = "list.ail"
target triple = "<NORMALIZED>"
@.str_fmt_int_0 = private unnamed_addr constant [6 x i8] c"%lld\0A\00", align 1
declare i32 @printf(ptr, ...)
declare i32 @puts(ptr)
declare ptr @malloc(i64)
define i64 @ail_sum_list(ptr %arg_xs) {
entry:
%v1 = load i64, ptr %arg_xs, align 8
switch i64 %v1, label %mdefault.2 [
i64 0, label %marm.2.0
i64 1, label %marm.2.1
]
marm.2.0:
br label %mjoin.2
marm.2.1:
%v3 = getelementptr inbounds i8, ptr %arg_xs, i64 8
%v4 = load i64, ptr %v3, align 8
%v5 = getelementptr inbounds i8, ptr %arg_xs, i64 16
%v6 = load ptr, ptr %v5, align 8
%v7 = call i64 @ail_sum_list(ptr %v6)
%v8 = add i64 %v4, %v7
br label %mjoin.2
mdefault.2:
unreachable
mjoin.2:
%v9 = phi i64 [ 0, %marm.2.0 ], [ %v8, %marm.2.1 ]
ret i64 %v9
}
define i8 @ail_main() {
entry:
%v1 = call ptr @malloc(i64 8)
store i64 0, ptr %v1, align 8
%v2 = call ptr @malloc(i64 24)
store i64 1, ptr %v2, align 8
%v3 = getelementptr inbounds i8, ptr %v2, i64 8
store i64 12, ptr %v3, align 8
%v4 = getelementptr inbounds i8, ptr %v2, i64 16
store ptr %v1, ptr %v4, align 8
%v5 = call ptr @malloc(i64 24)
store i64 1, ptr %v5, align 8
%v6 = getelementptr inbounds i8, ptr %v5, i64 8
store i64 20, ptr %v6, align 8
%v7 = getelementptr inbounds i8, ptr %v5, i64 16
store ptr %v2, ptr %v7, align 8
%v8 = call ptr @malloc(i64 24)
store i64 1, ptr %v8, align 8
%v9 = getelementptr inbounds i8, ptr %v8, i64 8
store i64 10, ptr %v9, align 8
%v10 = getelementptr inbounds i8, ptr %v8, i64 16
store ptr %v5, ptr %v10, align 8
%v11 = call i64 @ail_sum_list(ptr %v8)
call i32 (ptr, ...) @printf(ptr @.str_fmt_int_0, i64 %v11)
ret i8 0
}
define i32 @main() {
call i8 @ail_main()
ret i32 0
}
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; AILang generated module: max3
source_filename = "max3.ail"
target triple = "<NORMALIZED>"
@.str_fmt_int_0 = private unnamed_addr constant [6 x i8] c"%lld\0A\00", align 1
declare i32 @printf(ptr, ...)
declare i32 @puts(ptr)
declare ptr @malloc(i64)
define i64 @ail_max(i64 %arg_a, i64 %arg_b) {
entry:
%v1 = icmp sgt i64 %arg_a, %arg_b
br i1 %v1, label %then.2, label %else.2
then.2:
br label %join.2
else.2:
br label %join.2
join.2:
%v3 = phi i64 [ %arg_a, %then.2 ], [ %arg_b, %else.2 ]
ret i64 %v3
}
define i64 @ail_max3(i64 %arg_a, i64 %arg_b, i64 %arg_c) {
entry:
%v1 = icmp sgt i64 %arg_a, %arg_b
br i1 %v1, label %then.2, label %else.2
then.2:
%v3 = icmp sgt i64 %arg_a, %arg_c
br i1 %v3, label %then.4, label %else.4
then.4:
br label %join.4
else.4:
br label %join.4
join.4:
%v5 = phi i64 [ %arg_a, %then.4 ], [ %arg_c, %else.4 ]
br label %join.2
else.2:
%v6 = icmp sgt i64 %arg_b, %arg_c
br i1 %v6, label %then.7, label %else.7
then.7:
br label %join.7
else.7:
br label %join.7
join.7:
%v8 = phi i64 [ %arg_b, %then.7 ], [ %arg_c, %else.7 ]
br label %join.2
join.2:
%v9 = phi i64 [ %v5, %join.4 ], [ %v8, %join.7 ]
ret i64 %v9
}
define i8 @ail_main() {
entry:
%v1 = call i64 @ail_max3(i64 3, i64 17, i64 9)
call i32 (ptr, ...) @printf(ptr @.str_fmt_int_0, i64 %v1)
ret i8 0
}
define i32 @main() {
call i8 @ail_main()
ret i32 0
}
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; AILang generated module: sum
source_filename = "sum.ail"
target triple = "<NORMALIZED>"
@.str_fmt_int_0 = private unnamed_addr constant [6 x i8] c"%lld\0A\00", align 1
declare i32 @printf(ptr, ...)
declare i32 @puts(ptr)
declare ptr @malloc(i64)
define i64 @ail_sum(i64 %arg_n) {
entry:
%v1 = icmp eq i64 %arg_n, 0
br i1 %v1, label %then.2, label %else.2
then.2:
br label %join.2
else.2:
%v3 = sub i64 %arg_n, 1
%v4 = call i64 @ail_sum(i64 %v3)
%v5 = add i64 %arg_n, %v4
br label %join.2
join.2:
%v6 = phi i64 [ 0, %then.2 ], [ %v5, %else.2 ]
ret i64 %v6
}
define i8 @ail_main() {
entry:
%v1 = call i64 @ail_sum(i64 10)
call i32 (ptr, ...) @printf(ptr @.str_fmt_int_0, i64 %v1)
ret i8 0
}
define i32 @main() {
call i8 @ail_main()
ret i32 0
}