Add HL bytecode output test suite (tests/hlcode)

[Copilot]

Adds a test suite for validating HL code generation output, analogous to the JS optimization tests. Tests use a @:hl(<> ... </>) annotation containing output copied verbatim from dump/hlcode.txt.

Structure

tests/hlcode/
├── compile.hxml          # -main Main -D dump
└── src/
    ├── Main.hx           # minimal entry point
    ├── Macro.hx          # onAfterGenerate validator
    └── cases/            # one .hx file per test topic
        └── HlCodeTests.hx
tests/tools/
└── diff/                 # shared diff utility (moved from tests/misc/src/diff)

The macro auto-discovers all files in src/cases/ (all package cases;), reads dump/hlcode.txt after generation, looks up each annotated function by its fully-qualified name (e.g. cases.HlCodeTests.registerAffixDesc), and compares normalized output.

Normalization

Both expected and actual are normalized before comparison, making tests robust to unrelated changes:

• Source comment lines (;) — skipped entirely
• Function indices: fun@23(17h) → fun@N(Nh)
• Instruction source-line prefix: .12 @0 → @0
• Global IDs in global/setglobal → sequential $0, $1, … (per-function, order of first appearance)

Failure output

When a test fails, a unified diff is shown to make it easy to spot the difference:

| Test failed for cases.HlCodeTests.registerAffixDesc
| @@ -1,5 +1,5 @@
|  fun@N(Nh) ():virtual(target:enum(cases.EKind))
| -r0 virtual(target:WRONG_TYPE)
| +r0 virtual(target:enum(cases.EKind))
|  r1 enum(cases.EKind)
|  @0 new 0
|  @1 global 1, $0

Example test

@:hl(<>
    fun@364(16Ch) ():virtual(target:enum(cases.EKind))
    ; src/cases/HlCodeTests.hx:30 (cases.HlCodeTests.registerAffixDesc)
        r0 virtual(target:enum(cases.EKind))
        r1 enum(cases.EKind)
        .30    @0 new 0
        .30    @1 global 1, 18
        .30    @2 setfield 0[0],1
        .30    @3 ret 0
</>)
static public function registerAffixDesc():ApplicationDesc {
    return {target: Empty};
}

To add a test: compile with -D dump, copy the relevant block from dump/hlcode.txt into an @:hl(<> ... </>) annotation.

CI

Hooked into the HL target run (tests/runci/targets/Hl.hx) alongside the existing misc HL tests. Requires only the Haxe compiler — no HL runtime needed.

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[Simn]

@yuxiaomao Please check if this gives you a good workflow! Feel free to add some cases already, e.g. more of the stuff from #12682.

[Simn]

@copilot The only problem I'm seeing right now is that if a test fails it just dumps the expected/actual output at me which makes it hard to spot the actual difference. We have a small diff implementation in tests/misc/src/diff which we can use.

Let's take this opportunity to move it to tests/tools/diff so we don't have any weird test-suite interaction going on and all the general purpose stuff is in a more central area.

[Copilot]

@copilot The only problem I'm seeing right now is that if a test fails it just dumps the expected/actual output at me which makes it hard to spot the actual difference. We have a sma...

Done in 6f92728. The diff implementation has been moved from tests/misc/src/diff to tests/tools/diff, and tests/misc/compile.hxml updated to reference the new path. Macro.hx now uses it to show a unified diff on failure:

| Test failed for cases.HlCodeTests.registerAffixDesc
| @@ -1,5 +1,5 @@
|  fun@N(Nh) ():virtual(target:enum(cases.EKind))
| -r0 virtual(target:WRONG_TYPE)
| +r0 virtual(target:enum(cases.EKind))
|  r1 enum(cases.EKind)
|  @0 new 0
|  @1 global 1, $0