selfhost/cmd/{w6a,w6l}: migrate 6 amalloc sites to alloc(T{...})!

Phase 0 batch 1. Six typed-struct allocations switch from
amalloc(arena, NNu64): *T over-sized byte counts to alloc(T{...})!
with partial struct literal initialization. MAP_ANON-zero from
rt_alloc covers any field the literal omits — same contract the
amalloc bump arena provided via its explicit zero loop, but
without the rule-13 size literal at the call site.

Converted:
 - w6a/asm.ww  addreloc, addrelocdata, addfixup (areloc, afixup)
 - w6l/sym.ww  intern (lsym)
 - w6l/dyn.ww  loadso (lso), lexport

lexport's `if (vernamecs == nil) { e.version.ptr = nil;
e.version.len = 0i32; }` branch dropped — MAP_ANON-zero provides
the empty-version slot for free; the inverted `if (vernamecs !=
nil)` only takes the dcstrtostr path.

w6l/sym.ww:20 comment updated from "amalloc-zeroing" to
"alloc-zeroing gives 0, not -1" so the documented mechanism
matches the call.

w6a/obj.ww's 2 remaining amalloc sites (bufinit + bufgrow) are
runtime-N *u8 byte buffers, deferred to #8 (runtime-N alloc API).

Verified via 991_w6a_ww + 992_w6l_ww + 995_self_rebuild +
996_dyn_ww byte-identity. make test 132/132.

selfhost/cmd/w6a/asm.ww

@@ -40,13 +40,7 @@ export fn emitu32(a: *asm_, v: u32) void = {
 };
 
 export fn addreloc(a: *asm_, off: u64, kind: i32, s: *asym, add: i64) void = {
-	let r: *areloc = amalloc(a.a, 64u64): *areloc;
+	let r: *areloc = alloc(areloc { off = off, section = 0, kind = kind, asy = s, addend = add, rnext = a.relocs })!;
-	r.off = off;
-	r.section = 0;	// .text
-	r.kind = kind;
-	r.asy = s;
-	r.addend = add;
-	r.rnext = a.relocs;
 	a.relocs = r;
 };
 
@@ -54,13 +48,7 @@ export fn addreloc(a: *asm_, off: u64, kind: i32, s: *asym, add: i64) void = {
 // DATAR to patch a 64-bit slot with a symbol's runtime VA. obj.ww
 // separates these into .rela.data when emitting the .o.
 export fn addrelocdata(a: *asm_, off: u64, kind: i32, s: *asym, add: i64) void = {
-	let r: *areloc = amalloc(a.a, 64u64): *areloc;
+	let r: *areloc = alloc(areloc { off = off, section = 1, kind = kind, asy = s, addend = add, rnext = a.relocs })!;
-	r.off = off;
-	r.section = 1;	// .data
-	r.kind = kind;
-	r.asy = s;
-	r.addend = add;
-	r.rnext = a.relocs;
 	a.relocs = r;
 };
 
@@ -254,10 +242,7 @@ fn labeldefined(a: *asm_, name: str) bool = {
 // ---- fixup helper -----------------------------------------------------
 
 fn addfixup(a: *asm_, off: u64, label: str) void = {
-	let f: *afixup = amalloc(a.a, 48u64): *afixup;
+	let f: *afixup = alloc(afixup { off = off, label = label, fnext = a.fixups })!;
-	f.off = off;
-	f.label = label;
-	f.fnext = a.fixups;
 	a.fixups = f;
 };
 

selfhost/cmd/w6a/main.combined.ww

@@ -1783,13 +1783,7 @@ export fn emitu32(a: *asm_, v: u32) void = {
 };
 
 export fn addreloc(a: *asm_, off: u64, kind: i32, s: *asym, add: i64) void = {
-	let r: *areloc = amalloc(a.a, 64u64): *areloc;
+	let r: *areloc = alloc(areloc { off = off, section = 0, kind = kind, asy = s, addend = add, rnext = a.relocs })!;
-	r.off = off;
-	r.section = 0;	// .text
-	r.kind = kind;
-	r.asy = s;
-	r.addend = add;
-	r.rnext = a.relocs;
 	a.relocs = r;
 };
 
@@ -1797,13 +1791,7 @@ export fn addreloc(a: *asm_, off: u64, kind: i32, s: *asym, add: i64) void = {
 // DATAR to patch a 64-bit slot with a symbol's runtime VA. obj.ww
 // separates these into .rela.data when emitting the .o.
 export fn addrelocdata(a: *asm_, off: u64, kind: i32, s: *asym, add: i64) void = {
-	let r: *areloc = amalloc(a.a, 64u64): *areloc;
+	let r: *areloc = alloc(areloc { off = off, section = 1, kind = kind, asy = s, addend = add, rnext = a.relocs })!;
-	r.off = off;
-	r.section = 1;	// .data
-	r.kind = kind;
-	r.asy = s;
-	r.addend = add;
-	r.rnext = a.relocs;
 	a.relocs = r;
 };
 
@@ -1997,10 +1985,7 @@ fn labeldefined(a: *asm_, name: str) bool = {
 // ---- fixup helper -----------------------------------------------------
 
 fn addfixup(a: *asm_, off: u64, label: str) void = {
-	let f: *afixup = amalloc(a.a, 48u64): *afixup;
+	let f: *afixup = alloc(afixup { off = off, label = label, fnext = a.fixups })!;
-	f.off = off;
-	f.label = label;
-	f.fnext = a.fixups;
 	a.fixups = f;
 };
 

selfhost/cmd/w6l/dyn.ww

@@ -289,10 +289,7 @@ export fn loadso(l: *lnk, path: *u8) i32 = {
 
 	// Build the lso. Exports are appended in dynsym order so
 	// soprovides_v's first-match semantics match the C version.
-	let so: *lso = amalloc(l.a, 64u64): *lso;
+	let so: *lso = alloc(lso { path = dcstrtostr(l.a, path), soname = dcstrtostr(l.a, sonamecs) })!;
-	so.path = dcstrtostr(l.a, path);
-	so.soname = dcstrtostr(l.a, sonamecs);
-	so.exports = nil;
 	let tail: *lexport = nil;
 
 	let si: u64 = 1u64;
@@ -344,15 +341,10 @@ export fn loadso(l: *lnk, path: *u8) i32 = {
 			};
 
 			if (keep != 0) {
-				let e: *lexport = amalloc(l.a, 48u64): *lexport;
+				let e: *lexport = alloc(lexport { name = dcstrtostr(l.a, nmp) })!;
-				e.name = dcstrtostr(l.a, nmp);
+				if (vernamecs != nil) {
-				if (vernamecs == nil) {
-					e.version.ptr = nil;
-					e.version.len = 0i32;
-				} else {
 					e.version = dcstrtostr(l.a, vernamecs);
 				};
-				e.enext = nil;
 				if (tail == nil) {
 					so.exports = e;
 				} else {

selfhost/cmd/w6l/main.combined.ww

@@ -877,7 +877,7 @@ type lsym = struct {
 	idxinowner:  i32,
 	// Dynamic-linking fields. Set by resolve when an undefined sym
 	// is provided by some loaded lso. pltidx and dynsymidx default
-	// to -1 (set explicitly by resolve, not by amalloc-zeroing).
+	// to -1 (set explicitly by resolve; alloc-zeroing gives 0, not -1).
 	isdyn:       i32,
 	dynlib:      *lso,
 	dynversion:  str,	// matched export's version; len 0 if none
@@ -956,9 +956,7 @@ export fn intern(l: *lnk, name: str) *lsym = {
 		if (streq(s.name, name)) { return s; };
 		s = s.snext;
 	};
-	let n: *lsym = amalloc(l.a, 96u64): *lsym;
+	let n: *lsym = alloc(lsym { name = name, snext = l.syms })!;
-	n.name = name;
-	n.snext = l.syms;
 	l.syms = n;
 	return n;
 };
@@ -1876,10 +1874,7 @@ export fn loadso(l: *lnk, path: *u8) i32 = {
 
 	// Build the lso. Exports are appended in dynsym order so
 	// soprovides_v's first-match semantics match the C version.
-	let so: *lso = amalloc(l.a, 64u64): *lso;
+	let so: *lso = alloc(lso { path = dcstrtostr(l.a, path), soname = dcstrtostr(l.a, sonamecs) })!;
-	so.path = dcstrtostr(l.a, path);
-	so.soname = dcstrtostr(l.a, sonamecs);
-	so.exports = nil;
 	let tail: *lexport = nil;
 
 	let si: u64 = 1u64;
@@ -1931,15 +1926,10 @@ export fn loadso(l: *lnk, path: *u8) i32 = {
 			};
 
 			if (keep != 0) {
-				let e: *lexport = amalloc(l.a, 48u64): *lexport;
+				let e: *lexport = alloc(lexport { name = dcstrtostr(l.a, nmp) })!;
-				e.name = dcstrtostr(l.a, nmp);
+				if (vernamecs != nil) {
-				if (vernamecs == nil) {
-					e.version.ptr = nil;
-					e.version.len = 0i32;
-				} else {
 					e.version = dcstrtostr(l.a, vernamecs);
 				};
-				e.enext = nil;
 				if (tail == nil) {
 					so.exports = e;
 				} else {

selfhost/cmd/w6l/sym.ww

@@ -17,7 +17,7 @@ type lsym = struct {
 	idxinowner:  i32,
 	// Dynamic-linking fields. Set by resolve when an undefined sym
 	// is provided by some loaded lso. pltidx and dynsymidx default
-	// to -1 (set explicitly by resolve, not by amalloc-zeroing).
+	// to -1 (set explicitly by resolve; alloc-zeroing gives 0, not -1).
 	isdyn:       i32,
 	dynlib:      *lso,
 	dynversion:  str,	// matched export's version; len 0 if none
@@ -96,9 +96,7 @@ export fn intern(l: *lnk, name: str) *lsym = {
 		if (streq(s.name, name)) { return s; };
 		s = s.snext;
 	};
-	let n: *lsym = amalloc(l.a, 96u64): *lsym;
+	let n: *lsym = alloc(lsym { name = name, snext = l.syms })!;
-	n.name = name;
-	n.snext = l.syms;
 	l.syms = n;
 	return n;
 };