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docs(debugger): describe Frame global build as LLVMConstNamedStruct over getFrameStructType (A9.2)

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The compiled backend builds each trace Frame global as an LLVM named-struct
constant over the cached getFrameStructType() layout (file, line, col, func,
line_text) via LLVMConstNamedStruct -- a type-safe LLVM struct, not the sx
Frame TypeId / normal struct-emission path. Also correct the file field to
the source basename (full paths live in DWARF).
This commit is contained in:
agra
2026-06-03 14:28:28 +03:00
parent e6c51359fe
commit e907fc9e01
1 changed files with 13 additions and 8 deletions
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docs/debugger.md
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@@ -124,14 +124,19 @@ 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); the reflection builder
(`src/backend/llvm/reflection.zig`) 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 named-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