e388687f1a
104/104 regression tests pass. The Triple round-trip
(triple_imp writes {11, 22, 33} on the IMP side → #objc_call(Triple)
reads them back) is the test of record.
emit_llvm.zig changes:
1. `objc_msg_send` arm — when `needsByval(ret_ty)` (same predicate
the plain-foreign-call path uses), apply the sret transform:
- ret type collapses to void
- prepend a `ptr` param at index 0 (call site provides an
alloca slot)
- mirror `sret(<RetType>)` on the call site so the AArch64 x8
/ SysV-AMD64 hidden-ptr ABI lowers correctly
- load the result from the slot post-call
The IR shape now matches clang exactly:
call void @objc_msgSend(ptr sret({...}) %slot, ptr %recv, ptr %sel)
2. `.ret` arm — the body-side counterpart for sx fns whose declared
return type is sret-shaped (sx-defined IMPs registered via
`class_addMethod` produce these). When the current function's
`needsByval(func.ret)` predicate holds, store the IR ret value
through the prepended sret slot (param 0) and emit `ret void`.
Previously the unconditional coerceArg path turned the struct
value into `undef` and emitted `ret void undef` — illegal LLVM.
Test mechanics: registers `SxTripleProbe : NSObject` at runtime via
`objc_allocateClassPair` + `class_addMethod`, IMP returns
Triple{11, 22, 33}. `#objc_call(Triple)(instance, "tripleValue")`
gets them back, round-trip pinned in the .txt snapshot and the
IR-shape snapshot.
53 lines
2.1 KiB
Plaintext
53 lines
2.1 KiB
Plaintext
// Phase 1 step 1.8 (PLAN-FFI.md): >16 B non-HFA struct returns
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// through `#objc_call`. AAPCS64 routes these through the indirect-
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// return convention: caller allocates the result slot, passes its
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// pointer in x8 with the `sret(<T>)` attribute, callee writes
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// through it and returns void.
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//
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// Register a runtime-built Obj-C class with a method that returns
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// a fixed `Triple`. The IMP is a plain sx fn (callconv .c) — its
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// sret-shaped lowering already works (Phase 0.3 fix for plain
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// `#foreign` returns). The `#objc_call` dispatch side now produces
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// the matching call shape: `call void @objc_msgSend(ptr sret %slot,
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// ...)` + load. The two halves must agree on the ABI for the
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// round-trip to return the right bytes.
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#import "modules/std.sx";
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#import "modules/compiler.sx";
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#import "modules/std/objc.sx";
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Triple :: struct { a: s64; b: s64; c: s64; }
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// IMP for the runtime-installed method. Obj-C convention: implicit
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// (self, _cmd) prefix, then declared args. Returns the value bytes.
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triple_imp :: (self: *void, _cmd: *void) -> Triple callconv(.c) {
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Triple.{ a = 11, b = 22, c = 33 };
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}
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main :: () -> s32 {
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inline if OS == .macos {
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// Build the class:
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// @interface SxTripleProbe : NSObject
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// - (Triple)tripleValue;
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// @end
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ns_object := objc_getClass("NSObject".ptr);
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my_cls := objc_allocateClassPair(ns_object, "SxTripleProbe".ptr, 0);
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sel := sel_registerName("tripleValue".ptr);
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// Type encoding: {Triple=qqq}@: → returns 24 B struct of 3 s64,
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// implicit (self: id, _cmd: SEL).
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ok := class_addMethod(my_cls, sel, xx triple_imp, "{Triple=qqq}@:".ptr);
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print("addMethod = {}\n", ok);
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objc_registerClassPair(my_cls);
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// Call through #objc_call — sret transform applies because
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// Triple is 24 B non-HFA.
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instance := class_createInstance(my_cls, 0);
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t := #objc_call(Triple)(instance, "tripleValue");
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print("triple = ({}, {}, {})\n", t.a, t.b, t.c);
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}
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inline if OS != .macos {
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print("skipped (not macos)\n");
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}
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0;
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}
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