diff --git a/docs/debugger.md b/docs/debugger.md index 6c66467..85aa934 100644 --- a/docs/debugger.md +++ b/docs/debugger.md @@ -40,7 +40,7 @@ to satisfy all three. "JIT" and "comptime" are **not** the same thing. |---|---|---| | **AOT** (`sx build`) | native machine code in an on-disk binary | pointer to an interned `Frame` | | **JIT** (`sx run`) | ORC-JIT'd machine code in anonymous memory | pointer to an interned `Frame` | -| **Comptime** (`#run`) | the IR interpreter (`interp.zig`) — no machine code | packed `(func_id, ir_offset)` | +| **Comptime** (`#run`) | the IR interpreter (`interp.zig`) — no machine code | packed `(func_id, span.start)` | The crucial constraint: **the same lowered IR runs in the compiled backend *and* the interpreter.** So a value the IR produces (like a trace @@ -92,39 +92,55 @@ so the location — *and the offending source line itself* (`line_text`, for the formatter reads it directly. No PC capture, no DWARF, no symbolizer, no runtime file read. -A comptime frame is instead a packed `(func_id: u32, ir_offset: u32)`, -resolved through the interpreter's in-memory IR/source tables. The -interpreter **never dereferences the compiled `Frame` pointer** — it uses -its own representation — so the compiled and interpreted memory models -never collide. +A comptime frame is instead a packed `(func_id: u32, span.start: u32)` — +where `span.start` is the op's source byte offset — resolved through the +interpreter's in-memory IR/source tables. The interpreter **never +dereferences the compiled `Frame` pointer** — it uses its own +representation — so the compiled and interpreted memory models never +collide. ### The niladic trace-push op -Because the same IR runs in both machines, the push is a **dedicated, -niladic, span-stamped IR op** — the same pattern as `is_comptime` / -`interp_print_frames`. It carries **no operands and no global reference**; -each backend derives the frame from its own context: +Because the same IR runs in both machines, the frame value comes from a +**dedicated, niladic, span-stamped IR op** (`.trace_frame`) — the same +pattern as `is_comptime` / `interp_print_frames`. It carries **no operands +and no global reference**; each backend derives the frame from its own +context: -- **`emit_llvm`:** resolves the op's `span` + current function → - `{file, line, col, func}` (reusing the source map wired in for DWARF), - **interns and builds the `Frame` global in `emit_llvm`** (the same - mechanism as the tag-name table), then emits `call sx_trace_push(ptr)`. -- **`interp`:** pushes the packed `(func_id, ir_offset)` from its own - execution context. +- **`emit_llvm` (the `.trace_frame` arm):** resolves the op's `span` + + current function → `{file, line, col, func}` (reusing the source map + wired in for DWARF), **interns and builds the `Frame` global** in + [`src/backend/llvm/reflection.zig`](../src/backend/llvm/reflection.zig) + (the same mechanism, in the same file, as the tag-name table), and yields + its address as the op's value. The lowerer feeds that value to a separate + `sx_trace_push` call emitted through the normal call lowering. +- **`interp`:** yields the packed `(func_id, span.start)` from its own + execution context as the op's value. The separate `sx_trace_push` call + op consuming it is executed by the interp as a foreign call (via + `host_ffi`/dlsym, the same path as any extern), storing the packed value + in the buffer; the comptime `.trace_resolve` resolver later recovers + `file:line:col` from it. -This keeps the lowerer thin: at each push site it emits the op and nothing -else — no operand wiring, no global construction. The rejected -alternative — an op carrying a `GlobalId` to an IR-level `Frame` global — -would make the global visible to the interpreter (forcing comptime onto -the pointer-deref path) and fatten the lowerer; **do not do this.** +The op stays niladic by design: it carries no operand and no `GlobalId`, +so no IR-level `Frame` global is ever visible to the interpreter. The +rejected alternative — an op carrying a `GlobalId` to an IR-level `Frame` +global — would make the global visible to the interpreter (forcing +comptime onto the pointer-deref path) and fatten the lowerer; **do not do +this.** -`Frame` is defined **once** in sx (`trace.sx`/std); `emit_llvm` builds the -interned global off that `TypeId` through the normal struct-emission path, -never a bespoke byte layout (which would risk the "8-bytes-assumed" -clobber class of bug). `file`/`func` strings are interned into a shared -pool so a path shared by N push sites is stored once — the table stays -tiny. File paths are normalized to a stable relative form so trace output -is machine-independent and snapshot-testable. +`Frame` is defined **once** in sx (`trace.sx`/std), and its runtime layout — +`{ string file, i32 line, i32 col, string func, string line_text }` — is +mirrored by the cached LLVM **literal (anonymous) struct type** `getFrameStructType()` +(`src/ir/emit_llvm.zig`). The reflection builder +(`src/backend/llvm/reflection.zig`) assembles each push site's global as an +LLVM **named-struct constant** over that cached type via +`LLVMConstNamedStruct` — a type-safe LLVM struct, not hand-packed bytes +(which would risk the "8-bytes-assumed" clobber class of bug). It does +**not** derive the layout from the sx `Frame` `TypeId`, nor route through +the normal struct-emission path. `file`/`func`/`line_text` strings are +interned into a shared pool so a path shared by N push sites is stored once +— the table stays tiny. The `file` field is the source basename (full paths +live in DWARF), so trace output is machine-independent and snapshot-testable. ### Push and clear sites @@ -193,8 +209,9 @@ stripped without affecting traces. ### What's emitted -In [`src/ir/emit_llvm.zig`](../src/ir/emit_llvm.zig), gated on the same -debug opt levels + a wired source map (`setDebugContext`): +In [`src/backend/llvm/debug.zig`](../src/backend/llvm/debug.zig) (the +`DebugInfo` helper, driven from `emit_llvm`'s `emit()` pipeline), gated on +the same debug opt levels + a wired source map (`setDebugContext`): - one `DICompileUnit` + `DIFile` on the main file, - a `DISubprogram` per emitted function (`LLVMSetSubprogram`), @@ -237,10 +254,12 @@ both the trace path and the DWARF path. Items marked ✅ exist today; |---|---| | [`src/core.zig`](../src/core.zig) | `Compilation`: owns `import_sources` (file→source map), constructs the emitter, calls `setDebugContext` + `emit`; re-enters the interpreter for `#run`/post-link | | [`src/ir/lower.zig`](../src/ir/lower.zig) | AST→IR. Stamps `Inst.span`; emits push/clear at failure/absorb sites; `tracesEnabled` gate; declares the `sx_trace_*` externs | -| [`src/ir/emit_llvm.zig`](../src/ir/emit_llvm.zig) | IR→LLVM. Builds the interned `Frame` table; lowers the push op to a pointer push; emits all DWARF metadata | -| [`src/ir/interp.zig`](../src/ir/interp.zig) | Comptime IR interpreter. Lowers the push op to a packed `(func_id, offset)`; resolves comptime frames | +| [`src/ir/emit_llvm.zig`](../src/ir/emit_llvm.zig) | IR→LLVM orchestrator. Owns `LLVMEmitter` + the source map (`setDebugContext`); dispatches the `.trace_frame` op and the DWARF passes to the helpers below | +| [`src/backend/llvm/reflection.zig`](../src/backend/llvm/reflection.zig) | `Reflection`: builds the interned `Frame` table + the tag-name / type-name tables; yields the `.trace_frame` op's value (the `Frame` global's address) — the `sx_trace_push` call itself is emitted by `lower.zig` | +| [`src/backend/llvm/debug.zig`](../src/backend/llvm/debug.zig) | `DebugInfo`: builds all DWARF metadata (compile unit, per-function subprograms, per-instruction `DILocation`) | +| [`src/ir/interp.zig`](../src/ir/interp.zig) | Comptime IR interpreter. The `.trace_frame` op yields a packed `(func_id, span.start)`; the separate `sx_trace_push` call op runs as a foreign call (dlsym); `.trace_resolve` recovers comptime frames | | [`src/errors.zig`](../src/errors.zig) | `SourceLoc.compute(source, offset) → {line, col}`; the `import_sources` map type | -| [`src/ir/inst.zig`](../src/ir/inst.zig) | `Inst.span`, `Function.source_file`, the `Op` union (home of the trace-push op) | +| [`src/ir/inst.zig`](../src/ir/inst.zig) | `Inst.span`, `Function.source_file`, the `Op` union (home of the `.trace_frame` op) | | [`library/vendors/sx_trace_runtime/sx_trace.c`](../library/vendors/sx_trace_runtime/sx_trace.c) | the thread-local ring buffer + `sx_trace_report_unhandled` | | [`library/modules/trace.sx`](../library/modules/trace.sx) | the formatter (`to_string` / `print_current`) | | [`src/llvm_api.zig`](../src/llvm_api.zig) | binds `llvm-c/Core.h` + `llvm-c/DebugInfo.h` | @@ -270,17 +289,23 @@ traces and DWARF can never disagree: 1. `lower.zig` reaches a failure site — `lowerRaise`, `lowerTry`'s propagation branch, `lowerFailableOr`, or `lowerDestructureDecl` — and - (when `tracesEnabled()`) emits the niladic `.trace_frame_push` op, - replacing today's `emitTracePush(placeholderTraceFrame())`. Absorbing - sites emit `emitTraceClear()` → `call sx_trace_clear()`. -2. **Compiled backend** (`emit_llvm.emitInst`, `.trace_frame_push` arm): + (when `tracesEnabled()`) emits the niladic `.trace_frame` op via + `placeholderTraceFrame()`, whose result feeds a separate `sx_trace_push` + call via `emitTracePush()`. Absorbing sites emit `emitTraceClear()` → + `call sx_trace_clear()`. +2. **Compiled backend** (`emit_llvm.emitInst`, `.trace_frame` arm): resolve the op's `span` + current function → `{file,line,col,func}`, intern into the `Frame` table (built alongside `tag_name_array`), and - emit `call sx_trace_push(ptr_to_Frame)`. The `sx_trace_push` extern is + yield the `Frame` global's address as the op's value, which the separate + `sx_trace_push` call (step 1) consumes. The `sx_trace_push` extern is declared lazily by `getTraceFids()` (which sets `needs_trace_runtime`). 3. **Interpreter** (`interp.zig`, same op): pack `(current_func_id, - ir_offset)` into a `u64` and call the foreign `sx_trace_push` (resolved - via `host_ffi` `dlsym` against the linked `sx_trace.c`). + span.start)` into a `u64` and return it as the op's value. The separate + `sx_trace_push` call op is then executed by the interp as a foreign call + (`callForeign` → `host_ffi.lookupSymbol`/dlsym, the same path as any + extern), storing the packed value in the buffer. The comptime + `.trace_resolve` resolver later turns each packed value back into + `file:line:col` via the IR/source tables. **Buffer (run time) ✅** — `sx_trace.c` stores the `u64`s. Linked into the compiler so the JIT resolves `sx_trace_*` via `dlsym`; auto-injected as a @@ -288,10 +313,10 @@ compiler so the JIT resolves `sx_trace_*` via `dlsym`; auto-injected as a **Formatter (run time) ✅ (compiled 3a, comptime 3b)** — `trace.sx` `to_string()` loops `sx_trace_len()` / `sx_trace_frame_at(i)` and resolves each `u64` through -a **read-side context-split primitive** (the mirror of the push op): +a **read-side context-split primitive** (the mirror of the `.trace_frame` op): - compiled: cast the `u64` → `*Frame`, load the fields. -- comptime: unpack `(func_id, offset)`, resolve via the interpreter's +- comptime: unpack `(func_id, span.start)`, resolve via the interpreter's IR/source tables → a `Frame`. The same `trace.sx` source works in both because it runs in the matching @@ -330,8 +355,8 @@ the failable-`main` wrapper, whose `ret` path in `emit_llvm` ### The gate: one switch, two consumers -`Lowering.tracesEnabled()` (lower.zig) and `LLVMEmitter.debugEnabled()` -(emit_llvm) both reduce to `opt_level == .none or .less`. The `Frame` +`Lowering.tracesEnabled()` (lower.zig) and `DebugInfo.debugEnabled()` +(backend/llvm/debug.zig) both reduce to `opt_level == .none or .less`. The `Frame` table + push/clear ride `tracesEnabled`; DWARF rides `debugEnabled`. Release (`-O2`/`-O3`) emits neither. `sx run` defaults to `-O0` (both on); `sx ir`/`sx asm` default to `-O2` (both off) — which is why the `.ir` @@ -455,7 +480,7 @@ a Mach-O debug map, never register JIT DWARF. | IR instructions carry source spans | ✅ done — E3.0 slice 1 (`b44a5d0`) | | DWARF emission (compile unit / subprogram / line table) | ✅ done — E3.0 slice 2 (`c32d694`) | | Niladic trace-push op + interned `Frame` table (runtime) | ✅ done — E3.3 slice 3a (`1b6cbc1`) | -| Comptime resolver (`func_id, ir_offset` → location) | ✅ done — slice 3b | +| Comptime resolver (`func_id, span.start` → location) | ✅ done — slice 3b | | Source snippet + `^` caret | ✅ done — slice 3c (line embedded in `Frame`) | | `--emit-obj` artifact plumbing | ✅ done — slice 3d | | Stepping verification: macOS lldb | ✅ done — 3e rung 1 (`tests/debug_stepping_smoke.sh`) | diff --git a/docs/error-handling.md b/docs/error-handling.md index 251eb82..c746801 100644 --- a/docs/error-handling.md +++ b/docs/error-handling.md @@ -326,7 +326,9 @@ error trace: Traces are on by default in debug builds and compiled out in release (re-enable with `--release-traces`). They cost nothing on the success -path. Frame locations resolve through the binary's debug info, so +path. Each frame's location comes from `Frame` metadata +(file/line/col/func) baked in at the trace point — the trace resolves +itself with no debug info. Separately, sx emits standard DWARF, so `lldb` / `gdb` work on sx binaries too. Interpolating a tag with `{}` prints its **name**, not a number — in