harec

gen.c (116934B)

---

 #include <assert.h>
 #include <stdlib.h>
 #include <string.h>
 #include "check.h"
 #include "expr.h"
 #include "gen.h"
 #include "scope.h"
 #include "typedef.h"
 #include "types.h"
 #include "util.h"
 
 #define EXPR_GEN_VALUE -1
 
 static const struct gen_value gv_void = {
 	.kind = GV_CONST,
 	.type = &builtin_type_void,
 };
 
 static struct gen_value gen_expr(struct gen_context *ctx,
 	const struct expression *expr);
 static void gen_expr_at(struct gen_context *ctx,
 	const struct expression *expr,
 	struct gen_value out);
 static struct gen_value gen_expr_with(struct gen_context *ctx,
 	const struct expression *expr,
 	struct gen_value *out);
 static void gen_global_decl(struct gen_context *ctx,
 	const struct declaration *decl);
 
 static void
 gen_defers(struct gen_context *ctx, struct gen_scope *scope)
 {
 	if (ctx->deferring || !scope) {
 		return;
 	}
 	ctx->deferring = true;
 	if (scope->defers) {
 		pushc(ctx->current, "gen defers");
 	}
 	for (struct gen_defer *defer = scope->defers; defer;
 			defer = defer->next) {
 		gen_expr(ctx, defer->expr);
 	}
 	ctx->deferring = false;
 }
 
 static struct gen_scope *
 gen_scope_lookup(struct gen_context *ctx, const struct scope *which)
 {
 	for (struct gen_scope *scope = ctx->scope;
 			scope; scope = scope->parent) {
 		if (scope->scope == which) {
 			return scope;
 		}
 	}
 	abort();
 }
 
 static struct gen_scope *
 push_scope(struct gen_context *ctx, const struct scope *scope)
 {
 	struct gen_scope *new = xcalloc(1, sizeof(struct gen_scope));
 	new->parent = ctx->scope;
 	new->scope = scope;
 	ctx->scope = new;
 	return new;
 }
 
 static void
 pop_scope(struct gen_context *ctx, bool gendefers)
 {
 	if (gendefers) {
 		gen_defers(ctx, ctx->scope);
 	}
 	struct gen_scope *scope = ctx->scope;
 	ctx->scope = scope->parent;
 	for (struct gen_defer *defer = scope->defers; defer; /* n/a */) {
 		struct gen_defer *next = defer->next;
 		free(defer);
 		defer = next;
 	}
 	free(scope);
 }
 
 static void
 gen_copy_memcpy(struct gen_context *ctx,
 	struct gen_value dest, struct gen_value src)
 {
 	struct qbe_value rtfunc = mkrtfunc(ctx, "rt.memcpy");
 	struct qbe_value dtemp = mklval(ctx, &dest);
 	struct qbe_value stemp = mklval(ctx, &src);
 	struct qbe_value sz = constl(dest.type->size);
 	pushi(ctx->current, NULL, Q_CALL, &rtfunc, &dtemp, &stemp, &sz, NULL);
 }
 
 static void
 gen_copy_aligned(struct gen_context *ctx,
 	struct gen_value dest, struct gen_value src)
 {
 	if (dest.type->size > 128) {
 		gen_copy_memcpy(ctx, dest, src);
 		return;
 	}
 	struct qbe_value srcv = mkqval(ctx, &src);
 	struct qbe_value destv = mkqval(ctx, &dest);
 	struct qbe_value size = constl(dest.type->size);
 	pushi(ctx->current, NULL, Q_BLIT, &srcv, &destv, &size, NULL);
 }
 
 static void
 gen_store(struct gen_context *ctx,
 	struct gen_value object,
 	struct gen_value value)
 {
 	const struct type *ty = type_dealias(object.type);
 	switch (ty->storage) {
 	case STORAGE_ARRAY:
 	case STORAGE_SLICE:
 	case STORAGE_STRING:
 	case STORAGE_STRUCT:
 	case STORAGE_UNION:
 	case STORAGE_TAGGED:
 	case STORAGE_TUPLE:
 	case STORAGE_VALIST:
 		gen_copy_aligned(ctx, object, value);
 		return;
 	case STORAGE_ENUM:
 		object.type = ty->alias.type;
 		break;
 	default:
 		break; // no-op
 	}
 
 	struct qbe_value qobj = mkqval(ctx, &object),
 		qval = mkqval(ctx, &value);
 	enum qbe_instr qi = store_for_type(ctx, object.type);
 	pushi(ctx->current, NULL, qi, &qval, &qobj, NULL);
 }
 
 static struct gen_value
 gen_load(struct gen_context *ctx, struct gen_value object)
 {
 	const struct type *ty = type_dealias(object.type);
 	switch (ty->storage) {
 	case STORAGE_ARRAY:
 	case STORAGE_FUNCTION:
 	case STORAGE_SLICE:
 	case STORAGE_STRING:
 	case STORAGE_STRUCT:
 	case STORAGE_TAGGED:
 	case STORAGE_TUPLE:
 	case STORAGE_UNION:
 	case STORAGE_VALIST:
 		return object;
 	case STORAGE_ENUM:
 		object.type = ty->alias.type;
 		break;
 	default:
 		break; // no-op
 	}
 
 	struct gen_value value = {
 		.kind = GV_TEMP,
 		.type = object.type,
 		.name = gen_name(&ctx->id, "load.%d"),
 	};
 	struct qbe_value qobj = mkqval(ctx, &object),
 		qval = mkqval(ctx, &value);
 	enum qbe_instr qi = load_for_type(ctx, object.type);
 	pushi(ctx->current, &qval, qi, &qobj, NULL);
 	return value;
 }
 
 static void
 gen_fixed_abort(struct gen_context *ctx,
 	struct location loc, enum fixed_aborts reason)
 {
 	int n = snprintf(NULL, 0, "%s:%d:%d",
 			sources[loc.file], loc.lineno, loc.colno);
 	char *s = xcalloc(1, n + 1);
 	snprintf(s, n, "%s:%d:%d",
 			sources[loc.file], loc.lineno, loc.colno);
 	struct expression eloc = {0};
 	eloc.type = EXPR_CONSTANT;
 	eloc.result = &builtin_type_const_str;
 	eloc.constant.string.value = s;
 	eloc.constant.string.len = n - 1;
 	struct gen_value msg = gen_expr(ctx, &eloc);
 	struct qbe_value qmsg = mkqval(ctx, &msg);
 	struct qbe_value rtabort = mkrtfunc(ctx, "rt.abort_fixed");
 	struct qbe_value tmp = constl(reason);
 	pushi(ctx->current, NULL, Q_CALL, &rtabort, &qmsg, &tmp, NULL);
 }
 
 static struct gen_value
 gen_autoderef(struct gen_context *ctx, struct gen_value val)
 {
 	while (type_dealias(val.type)->storage == STORAGE_POINTER) {
 		val.type = type_dealias(val.type)->pointer.referent;
 		val = gen_load(ctx, val);
 	}
 	return val;
 }
 
 static struct gen_value
 gen_access_ident(struct gen_context *ctx, const struct scope_object *obj)
 {
 	switch (obj->otype) {
 	case O_BIND:
 		for (const struct gen_binding *gb = ctx->bindings;
 				gb; gb = gb->next) {
 			if (gb->object == obj) {
 				return gb->value;
 			}
 		}
 		break;
 	case O_DECL:
 		return (struct gen_value){
 			.kind = GV_GLOBAL,
 			.type = obj->type,
 			.name = ident_to_sym(&obj->ident),
 			.threadlocal = obj->threadlocal,
 		};
 	case O_CONST:
 	case O_TYPE:
 	case O_SCAN:
 		abort(); // Invariant
 	}
 	abort(); // Invariant
 }
 
 static struct gen_value
 gen_access_index(struct gen_context *ctx, const struct expression *expr)
 {
 	struct gen_value glval = gen_expr(ctx, expr->access.array);
 	glval = gen_autoderef(ctx, glval);
 	struct qbe_value qlval = mkqval(ctx, &glval);
 	struct qbe_value qival = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 	bool checkbounds = !expr->access.bounds_checked;
 	struct qbe_value length;
 	const struct type *ty = type_dealias(glval.type);
 	switch (ty->storage) {
 	case STORAGE_SLICE:;
 		enum qbe_instr load = load_for_type(ctx, &builtin_type_size);
 		struct qbe_value base = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 		pushi(ctx->current, &base, load, &qlval, NULL);
 
 		struct qbe_value temp = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 		length = mkqtmp(ctx, ctx->arch.sz, "len.%d");
 		struct qbe_value offset = constl(builtin_type_size.size);
 		pushi(ctx->current, &temp, Q_ADD, &qlval, &offset, NULL);
 		pushi(ctx->current, &length, load, &temp, NULL);
 
 		qlval = base;
 		break;
 	case STORAGE_ARRAY:
 		if (ty->array.length != SIZE_UNDEFINED) {
 			length = constl(ty->array.length);
 		} else {
 			checkbounds = false;
 		}
 		break;
 	default:
 		assert(0); // Unreachable
 	}
 
 	struct gen_value index = gen_expr(ctx, expr->access.index);
 	struct qbe_value qindex = mkqval(ctx, &index);
 	struct qbe_value itemsz = constl(expr->result->size);
 	pushi(ctx->current, &qival, Q_MUL, &qindex, &itemsz, NULL);
 	pushi(ctx->current, &qival, Q_ADD, &qlval, &qival, NULL);
 
 	if (checkbounds) {
 		struct qbe_value valid = mkqtmp(ctx, &qbe_word, ".%d");
 		pushi(ctx->current, &valid, Q_CULTL, &qindex, &length, NULL);
 
 		struct qbe_statement linvalid, lvalid;
 		struct qbe_value binvalid = mklabel(ctx, &linvalid, ".%d");
 		struct qbe_value bvalid = mklabel(ctx, &lvalid, ".%d");
 
 		pushi(ctx->current, NULL, Q_JNZ, &valid, &bvalid, &binvalid, NULL);
 		push(&ctx->current->body, &linvalid);
 		gen_fixed_abort(ctx, expr->loc, ABORT_OOB);
 		push(&ctx->current->body, &lvalid);
 	}
 
 	return (struct gen_value){
 		.kind = GV_TEMP,
 		.type = expr->result,
 		.name = qival.name,
 	};
 }
 
 static struct gen_value
 gen_access_field(struct gen_context *ctx, const struct expression *expr)
 {
 	const struct struct_field *field = expr->access.field;
 	struct gen_value glval = gen_expr(ctx, expr->access._struct);
 	glval = gen_autoderef(ctx, glval);
 	struct qbe_value qlval = mkqval(ctx, &glval);
 	struct qbe_value qfval = mkqtmp(ctx, ctx->arch.ptr, "field.%d");
 	struct qbe_value offs = constl(field->offset);
 	pushi(ctx->current, &qfval, Q_ADD, &qlval, &offs, NULL);
 	return (struct gen_value){
 		.kind = GV_TEMP,
 		.type = field->type,
 		.name = qfval.name,
 	};
 }
 
 static struct gen_value
 gen_access_value(struct gen_context *ctx, const struct expression *expr)
 {
 	const struct type_tuple *tuple = expr->access.tvalue;
 	struct gen_value glval = gen_expr(ctx, expr->access.tuple);
 	glval = gen_autoderef(ctx, glval);
 	struct qbe_value qlval = mkqval(ctx, &glval);
 	struct qbe_value qfval = mkqtmp(ctx, ctx->arch.ptr, "value.%d");
 	struct qbe_value offs = constl(tuple->offset);
 	pushi(ctx->current, &qfval, Q_ADD, &qlval, &offs, NULL);
 	return (struct gen_value){
 		.kind = GV_TEMP,
 		.type = tuple->type,
 		.name = qfval.name,
 	};
 }
 
 static struct gen_value
 gen_expr_access_addr(struct gen_context *ctx, const struct expression *expr)
 {
 	struct gen_value addr;
 	switch (expr->access.type) {
 	case ACCESS_IDENTIFIER:
 		addr = gen_access_ident(ctx, expr->access.object);
 		break;
 	case ACCESS_INDEX:
 		addr = gen_access_index(ctx, expr);
 		break;
 	case ACCESS_FIELD:
 		addr = gen_access_field(ctx, expr);
 		break;
 	case ACCESS_TUPLE:
 		addr = gen_access_value(ctx, expr);
 		break;
 	}
 	return addr;
 }
 
 static struct gen_value
 gen_expr_access(struct gen_context *ctx, const struct expression *expr)
 {
 	struct gen_value addr = gen_expr_access_addr(ctx, expr);
 	return gen_load(ctx, addr);
 }
 
 static void
 gen_alloc_slice_at(struct gen_context *ctx,
 		const struct expression *expr,
 		struct gen_value out,
 		bool expand)
 {
 	struct qbe_value qcap;
 	if (expr->alloc.cap) {
 		struct gen_value cap = gen_expr(ctx, expr->alloc.cap);
 		qcap = mkqval(ctx, &cap);
 	}
 
 	struct gen_value init;
 	struct qbe_value qinit;
 	struct qbe_value length, initdata;
 	const struct type *inittype = type_dealias(expr->alloc.init->result);
 	switch (inittype->storage) {
 	case STORAGE_ARRAY:
 		assert(inittype->array.length != SIZE_UNDEFINED);
 		length = constl(inittype->array.length);
 		break;
 	case STORAGE_SLICE:
 		init = gen_expr(ctx, expr->alloc.init);
 		qinit = mkqval(ctx, &init);
 		enum qbe_instr load = load_for_type(ctx, &builtin_type_size);
 		initdata = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 		pushi(ctx->current, &initdata, load, &qinit, NULL);
 		struct qbe_value offset = constl(builtin_type_size.size);
 		struct qbe_value ptr = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 		pushi(ctx->current, &ptr, Q_ADD, &qinit, &offset, NULL);
 		length = mkqtmp(ctx, ctx->arch.sz, ".%d");
 		pushi(ctx->current, &length, load, &ptr, NULL);
 		break;
 	default: abort(); // Invariant
 	}
 
 	if (!expr->alloc.cap) {
 		qcap = length;
 	}
 
 	const struct type *sltype = type_dealias(expr->result);
 	struct qbe_value isize = constl(sltype->array.members->size);
 	struct qbe_value size = mkqtmp(ctx, ctx->arch.sz, ".%d");
 	pushi(ctx->current, &size, Q_MUL, &qcap, &isize, NULL);
 
 	struct qbe_statement lzero, lnonzero;
 	struct qbe_value bzero = mklabel(ctx, &lzero, ".%d");
 	struct qbe_value bnonzero = mklabel(ctx, &lnonzero, ".%d");
 
 	struct qbe_value rtfunc = mkrtfunc(ctx, "rt.malloc");
 	struct qbe_value data = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 	struct qbe_value cmpres = mkqtmp(ctx, &qbe_word, ".%d");
 	struct qbe_value zero = constl(0);
 	pushi(ctx->current, &data, Q_COPY, &zero, NULL);
 	pushi(ctx->current, &cmpres, Q_CNEL, &size, &zero, NULL);
 	pushi(ctx->current, NULL, Q_JNZ, &cmpres, &bnonzero, &bzero, NULL);
 	push(&ctx->current->body, &lnonzero);
 	pushi(ctx->current, &data, Q_CALL, &rtfunc, &size, NULL);
 
 	struct qbe_statement linvalid;
 	struct qbe_value binvalid = mklabel(ctx, &linvalid, ".%d");
 	pushi(ctx->current, &cmpres, Q_CNEL, &data, &zero, NULL);
 	pushi(ctx->current, NULL, Q_JNZ, &cmpres, &bzero, &binvalid, NULL);
 	push(&ctx->current->body, &linvalid);
 	gen_fixed_abort(ctx, expr->loc, ABORT_ALLOC_FAILURE);
 	push(&ctx->current->body, &lzero);
 
 	struct qbe_value base = mklval(ctx, &out);
 	struct qbe_value ptr = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 	struct qbe_value offset = constl(builtin_type_size.size);
 	enum qbe_instr store = store_for_type(ctx, &builtin_type_size);
 	pushi(ctx->current, NULL, store, &data, &base, NULL);
 	pushi(ctx->current, &ptr, Q_ADD, &base, &offset, NULL);
 
 	if (expand) {
 		pushi(ctx->current, NULL, store, &qcap, &ptr, NULL);
 	} else {
 		pushi(ctx->current, NULL, store, &length, &ptr, NULL);
 	}
 
 	offset = constl(builtin_type_size.size * 2);
 	pushi(ctx->current, &ptr, Q_ADD, &base, &offset, NULL);
 	pushi(ctx->current, NULL, store, &qcap, &ptr, NULL);
 
 	if (inittype->storage == STORAGE_ARRAY) {
 		struct gen_value storage = (struct gen_value){
 			.kind = GV_TEMP,
 			.type = inittype,
 			.name = data.name,
 		};
 		gen_expr_at(ctx, expr->alloc.init, storage);
 	} else {
 		struct qbe_value copysize = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 		pushi(ctx->current, &copysize, Q_MUL, &length, &isize, NULL);
 		struct qbe_value rtmemcpy = mkrtfunc(ctx, "rt.memcpy");
 		pushi(ctx->current, NULL, Q_CALL, &rtmemcpy,
 				&data, &initdata, &copysize, NULL);
 	}
 
 	if (!expand) {
 		return;
 	}
 
 	struct qbe_value last = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 	struct qbe_value next = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 	pushi(ctx->current, &next, Q_MUL, &length, &isize, NULL);
 	pushi(ctx->current, &next, Q_ADD, &next, &data, NULL);
 	pushi(ctx->current, &last, Q_SUB, &next, &isize, NULL);
 	struct qbe_value remain = mkqtmp(ctx, ctx->arch.sz, ".%d");
 	pushi(ctx->current, &remain, Q_SUB, &qcap, &length, NULL);
 	pushi(ctx->current, &remain, Q_MUL, &remain, &isize, NULL);
 	struct qbe_value rtmemcpy = mkrtfunc(ctx, "rt.memcpy");
 	pushi(ctx->current, NULL, Q_CALL, &rtmemcpy, &next, &last, &remain, NULL);
 }
 
 static struct gen_value
 gen_expr_alloc_init_with(struct gen_context *ctx,
 	const struct expression *expr, struct gen_value *out)
 {
 	// alloc(init) case
 	assert(expr->alloc.cap == NULL);
 
 	const struct type *objtype = type_dealias(expr->result);
 	assert(objtype->storage == STORAGE_POINTER);
 	objtype = objtype->pointer.referent;
 
 	struct qbe_value sz = constl(objtype->size);
 	struct gen_value result = mkgtemp(ctx, expr->result, ".%d");
 	struct qbe_value qresult = mkqval(ctx, &result);
 	struct qbe_value rtfunc = mkrtfunc(ctx, "rt.malloc");
 	pushi(ctx->current, &qresult, Q_CALL, &rtfunc, &sz, NULL);
 
 	if (!(type_dealias(expr->result)->pointer.flags & PTR_NULLABLE)) {
 		struct qbe_statement linvalid, lvalid;
 		struct qbe_value cmpres = mkqtmp(ctx, &qbe_word, ".%d");
 		struct qbe_value zero = constl(0);
 		struct qbe_value binvalid = mklabel(ctx, &linvalid, ".%d");
 		struct qbe_value bvalid = mklabel(ctx, &lvalid, ".%d");
 
 		pushi(ctx->current, &cmpres, Q_CNEL, &qresult, &zero, NULL);
 		pushi(ctx->current, NULL, Q_JNZ, &cmpres, &bvalid, &binvalid, NULL);
 		push(&ctx->current->body, &linvalid);
 		gen_fixed_abort(ctx, expr->loc, ABORT_ALLOC_FAILURE);
 		push(&ctx->current->body, &lvalid);
 	}
 
 	struct gen_value object = {
 		.kind = GV_TEMP,
 		.type = objtype,
 		.name = result.name,
 	};
 	gen_expr_at(ctx, expr->alloc.init, object);
 	if (out) {
 		gen_store(ctx, *out, result);
 	}
 	return result;
 }
 
 static struct gen_value
 gen_expr_alloc_slice_with(struct gen_context *ctx,
 	const struct expression *expr, struct gen_value *out)
 {
 	// alloc(init, cap | len) case
 	bool expand = expr->alloc.kind == ALLOC_WITH_LEN;
 	if (out) {
 		gen_alloc_slice_at(ctx, expr, *out, expand);
 		return gv_void;
 	}
 	struct gen_value temp = mkgtemp(ctx, expr->result, "object.%d");
 	struct qbe_value base = mkqval(ctx, &temp);
 	struct qbe_value sz = constl(expr->result->size);
 	enum qbe_instr alloc = alloc_for_align(expr->result->align);
 	pushprei(ctx->current, &base, alloc, &sz, NULL);
 	gen_alloc_slice_at(ctx, expr, temp, expand);
 	return temp;
 }
 
 static struct gen_value
 gen_expr_alloc_copy_with(struct gen_context *ctx,
 	const struct expression *expr, struct gen_value *out)
 {
 	// alloc(init...) case
 	assert(expr->alloc.cap == NULL);
 
 	struct gen_value ret = gv_void;
 	if (out == NULL) {
 		ret = mkgtemp(ctx, expr->result, "object.%d");
 		out = &ret;
 
 		struct qbe_value base = mkqval(ctx, out);
 		struct qbe_value sz = constl(expr->result->size);
 		enum qbe_instr alloc = alloc_for_align(expr->result->align);
 		pushprei(ctx->current, &base, alloc, &sz, NULL);
 	}
 
 	enum qbe_instr load = load_for_type(ctx, &builtin_type_size);
 	enum qbe_instr store = store_for_type(ctx, &builtin_type_size);
 
 	struct gen_value src = gen_expr(ctx, expr->alloc.init);
 	struct qbe_value dbase = mkcopy(ctx, out, ".%d");
 	struct qbe_value offs = constl(builtin_type_size.size);
 
 	const struct type *initres = type_dealias(expr->alloc.init->result);
 	struct qbe_value srcdata;
 	struct qbe_value length;
 	if (initres->storage == STORAGE_SLICE) {
 		assert(initres->array.length == SIZE_UNDEFINED);
 		srcdata = mkqtmp(ctx, ctx->arch.sz, ".%d");
 		struct qbe_value sbase = mkcopy(ctx, &src, ".%d");
 		pushi(ctx->current, &srcdata, load, &sbase, NULL);
 		pushi(ctx->current, &sbase, Q_ADD, &sbase, &offs, NULL);
 		length = mkqtmp(ctx, ctx->arch.sz, ".%d");
 		pushi(ctx->current, &length, load, &sbase, NULL);
 	} else if (initres->storage == STORAGE_ARRAY) {
 		assert(initres->array.length != SIZE_UNDEFINED);
 		srcdata = mkcopy(ctx, &src, ".%d"); // TODO: object.%d
 		length = constl(initres->array.length);
 	} else {
 		abort();
 	}
 
 	struct qbe_statement linvalid, lvalid, lalloc, lcopy;
 	struct qbe_value balloc = mklabel(ctx, &lalloc, ".%d");
 	struct qbe_value binvalid = mklabel(ctx, &linvalid, ".%d");
 	struct qbe_value bvalid = mklabel(ctx, &lvalid, ".%d");
 	struct qbe_value bcopy = mklabel(ctx, &lcopy, ".%d");
 
 	struct qbe_value cmpres = mkqtmp(ctx, &qbe_word, ".%d");
 	struct qbe_value newdata = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 	struct qbe_value zero = constl(0);
 	pushi(ctx->current, &newdata, Q_COPY, &zero, NULL);
 	pushi(ctx->current, &cmpres, Q_CNEL, &length, &zero, NULL);
 	pushi(ctx->current, NULL, Q_JNZ, &cmpres, &balloc, &bvalid, NULL);
 	push(&ctx->current->body, &lalloc);
 
 	const struct type *result = type_dealias(expr->result);
 	assert(result->storage == STORAGE_SLICE);
 	struct qbe_value sz = mkqtmp(ctx, ctx->arch.sz, ".%d");
 	struct qbe_value membsz = constl(result->array.members->size);
 	pushi(ctx->current, &sz, Q_MUL, &membsz, &length, NULL);
 
 	struct qbe_value rtfunc = mkrtfunc(ctx, "rt.malloc");
 	pushi(ctx->current, &newdata, Q_CALL, &rtfunc, &sz, NULL);
 	pushi(ctx->current, &cmpres, Q_CNEL, &newdata, &zero, NULL);
 	pushi(ctx->current, NULL, Q_JNZ, &cmpres, &bcopy, &binvalid, NULL);
 
 	push(&ctx->current->body, &linvalid);
 	gen_fixed_abort(ctx, expr->loc, ABORT_ALLOC_FAILURE);
 
 	push(&ctx->current->body, &lcopy);
 	struct qbe_value rtmemcpy = mkrtfunc(ctx, "rt.memcpy");
 	pushi(ctx->current, NULL, Q_CALL, &rtmemcpy, &newdata, &srcdata, &sz, NULL);
 
 	push(&ctx->current->body, &lvalid);
 	pushi(ctx->current, NULL, store, &newdata, &dbase, NULL);
 	pushi(ctx->current, &dbase, Q_ADD, &dbase, &offs, NULL);
 	pushi(ctx->current, NULL, store, &length, &dbase, NULL);
 	pushi(ctx->current, &dbase, Q_ADD, &dbase, &offs, NULL);
 	pushi(ctx->current, NULL, store, &length, &dbase, NULL);
 
 	return ret;
 }
 
 static struct gen_value
 gen_expr_alloc_with(struct gen_context *ctx,
 	const struct expression *expr, struct gen_value *out)
 {
 	switch (expr->alloc.kind) {
 	case ALLOC_OBJECT:
 		return gen_expr_alloc_init_with(ctx, expr, out);
 	case ALLOC_WITH_CAP:
 	case ALLOC_WITH_LEN:
 		return gen_expr_alloc_slice_with(ctx, expr, out);
 	case ALLOC_COPY:
 		return gen_expr_alloc_copy_with(ctx, expr, out);
 	}
 	abort(); // Unreachable
 }
 
 static struct gen_value
 gen_expr_append(struct gen_context *ctx, const struct expression *expr)
 {
 	struct gen_value slice = gen_expr(ctx, expr->append.object);
 	slice = gen_autoderef(ctx, slice);
 	struct qbe_value qslice = mkqval(ctx, &slice);
 
 	struct qbe_value lenptr = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 	struct qbe_value prevlen = mkqtmp(ctx, ctx->arch.sz, ".%d");
 	struct qbe_value offs = constl(builtin_type_size.size);
 	pushi(ctx->current, &lenptr, Q_ADD, &qslice, &offs, NULL);
 	enum qbe_instr load = load_for_type(ctx, &builtin_type_size);
 	pushi(ctx->current, &prevlen, load, &lenptr, NULL);
 
 	struct qbe_value appendlen;
 	const struct type *valtype = type_dealias(expr->append.value->result);
 	if (expr->append.length != NULL) {
 		struct gen_value length = gen_expr(ctx, expr->append.length);
 		appendlen = mkqval(ctx, &length);
 		assert(valtype->storage == STORAGE_ARRAY && valtype->array.expandable);
 	} else if (!expr->append.is_multi) {
 		appendlen = constl(1);
 	}
 
 	struct gen_value value;
 	struct qbe_value qvalue;
 	if (!expr->append.is_multi || valtype->storage != STORAGE_ARRAY) {
 		// We use gen_expr_at for the array case to avoid a copy
 		value = gen_expr(ctx, expr->append.value);
 		qvalue = mkqval(ctx, &value);
 	}
 
 	if (expr->append.is_multi) {
 		if (valtype->storage == STORAGE_ARRAY) {
 			assert(valtype->array.length != SIZE_UNDEFINED);
 			appendlen = constl(valtype->array.length);
 		} else {
 			appendlen = mkqtmp(ctx, ctx->arch.sz, ".%d");
 			struct qbe_value ptr = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 			offs = constl(builtin_type_size.size);
 			pushi(ctx->current, &ptr, Q_ADD, &qvalue, &offs, NULL);
 			pushi(ctx->current, &appendlen, load, &ptr, NULL);
 		}
 	}
 
 	struct qbe_value newlen = mkqtmp(ctx, ctx->arch.sz, ".%d");
 	pushi(ctx->current, &newlen, Q_ADD, &prevlen, &appendlen, NULL);
 	enum qbe_instr store = store_for_type(ctx, &builtin_type_size);
 	pushi(ctx->current, NULL, store, &newlen, &lenptr, NULL);
 
 	struct qbe_value ptr = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 	const struct type *mtype = type_dealias(slice.type)->array.members;
 	struct qbe_value membsz = constl(mtype->size);
 	if (!expr->append.is_static) {
 		struct qbe_value rtfunc = mkrtfunc(ctx, "rt.ensure");
 		struct qbe_value lval = mklval(ctx, &slice);
 		pushi(ctx->current, NULL, Q_CALL, &rtfunc, &lval, &membsz, NULL);
 	} else {
 		offs = constl(builtin_type_size.size * 2);
 		pushi(ctx->current, &ptr, Q_ADD, &qslice, &offs, NULL);
 		struct qbe_value cap = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 		pushi(ctx->current, &cap, load, &ptr, NULL);
 
 		struct qbe_statement lvalid, linvalid;
 		struct qbe_value bvalid = mklabel(ctx, &lvalid, ".%d");
 		struct qbe_value binvalid = mklabel(ctx, &linvalid, ".%d");
 		struct qbe_value valid = mkqtmp(ctx, &qbe_word, ".%d");
 		pushi(ctx->current, &valid, Q_CULEL, &newlen, &cap, NULL);
 		pushi(ctx->current, NULL, Q_JNZ, &valid, &bvalid, &binvalid, NULL);
 
 		push(&ctx->current->body, &linvalid);
 		gen_fixed_abort(ctx, expr->loc, ABORT_OOB);
 		push(&ctx->current->body, &lvalid);
 	}
 
 	offs = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 	pushi(ctx->current, &ptr, load, &qslice, NULL);
 	pushi(ctx->current, &offs, Q_MUL, &prevlen, &membsz, NULL);
 	pushi(ctx->current, &ptr, Q_ADD, &ptr, &offs, NULL);
 
 	struct gen_value item = {
 		.kind = GV_TEMP,
 		.type = mtype,
 		.name = ptr.name,
 	};
 	if (expr->append.is_multi && valtype->storage == STORAGE_ARRAY) {
 		item.type = valtype;
 		gen_expr_at(ctx, expr->append.value, item);
 	} else if (expr->append.is_multi && valtype->storage == STORAGE_SLICE) {
 		struct qbe_value qsrc = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 		struct qbe_value rtfunc = mkrtfunc(ctx, "rt.memmove");
 		struct qbe_value sz = mkqtmp(ctx, ctx->arch.sz, ".%d");
 		pushi(ctx->current, &sz, Q_MUL, &appendlen, &membsz, NULL);
 		pushi(ctx->current, &qsrc, load, &qvalue, NULL);
 		pushi(ctx->current, NULL, Q_CALL, &rtfunc, &ptr, &qsrc, &sz, NULL);
 	} else if (expr->append.length != NULL) {
 		// XXX: This could be made more efficient for some cases if
 		// check could determine the length at compile time and lower it
 		// to a fixed-length array type
 		assert(valtype->storage == STORAGE_ARRAY);
 		item.type = valtype;
 		gen_expr_at(ctx, expr->append.value, item);
 
 		assert(valtype->array.length != SIZE_UNDEFINED);
 		struct qbe_value next = mkqtmp(ctx, ctx->arch.ptr, "next.%d");
 		struct qbe_value last = mkqtmp(ctx, ctx->arch.ptr, "last.%d");
 		struct qbe_value arlen = constl(valtype->array.length * mtype->size);
 		pushi(ctx->current, &next, Q_ADD, &ptr, &arlen, NULL);
 		arlen = constl((valtype->array.length - 1) * mtype->size);
 		pushi(ctx->current, &last, Q_ADD, &ptr, &arlen, NULL);
 
 		struct qbe_value rtfunc = mkrtfunc(ctx, "rt.memcpy");
 		struct qbe_value remain = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 		struct qbe_value one = constl(1);
 		pushi(ctx->current, &remain, Q_SUB, &appendlen, &one, NULL);
 		pushi(ctx->current, &remain, Q_MUL, &remain, &membsz, NULL);
 		pushi(ctx->current, NULL, Q_CALL, &rtfunc, &next, &last, &remain, NULL);
 	} else {
 		gen_store(ctx, item, value);
 	}
 
 	return gv_void;
 }
 
 static struct gen_value
 gen_expr_assert(struct gen_context *ctx, const struct expression *expr)
 {
 	assert(expr->assert.message); // Invariant
 	if (expr->assert.is_static) {
 		return gv_void;
 	}
 
 	struct gen_value msg;
 	struct qbe_statement failedl, passedl;
 	struct qbe_value rtfunc = mkrtfunc(ctx, "rt.abort");
 	if (expr->assert.cond) {
 		struct qbe_value bfailed = mklabel(ctx, &failedl, "failed.%d");
 		struct qbe_value bpassed = mklabel(ctx, &passedl, "passed.%d");
 		struct gen_value cond = gen_expr(ctx, expr->assert.cond);
 		struct qbe_value qcond = mkqval(ctx, &cond);
 		pushi(ctx->current, NULL, Q_JNZ, &qcond, &bpassed, &bfailed, NULL);
 		push(&ctx->current->body, &failedl);
 		msg = gen_expr(ctx, expr->assert.message);
 	} else {
 		msg = gen_expr(ctx, expr->assert.message);
 	}
 
 	for (struct gen_scope *scope = ctx->scope; scope; scope = scope->parent) {
 		gen_defers(ctx, scope);
 	}
 
 	struct qbe_value qmsg = mkqval(ctx, &msg);
 	pushi(ctx->current, NULL, Q_CALL, &rtfunc, &qmsg, NULL);
 
 	if (expr->assert.cond) {
 		push(&ctx->current->body, &passedl);
 	}
 
 	return gv_void;
 }
 
 static struct gen_value
 gen_expr_assign_slice_expandable(struct gen_context *ctx, const struct expression *expr)
 {
 	struct gen_value obj = gen_expr(ctx, expr->assign.object);
 	struct qbe_value qobj = mkqval(ctx, &obj);
 	
 	// get the length of the copy
 	struct qbe_value step = constl(ctx->arch.ptr->size);
 	struct qbe_value ptr = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 	struct qbe_value olen = mkqtmp(ctx, ctx->arch.sz, ".%d");
 	pushi(ctx->current, &ptr, Q_ADD, &qobj, &step, NULL);
 	pushi(ctx->current, &olen, Q_LOADL, &ptr, NULL);
 	
 	// check if there is anything to do
 	struct qbe_statement lzero, lnonzero;
 	struct qbe_value bzero = mklabel(ctx, &lzero, ".%d");
 	struct qbe_value bnonzero = mklabel(ctx, &lnonzero, ".%d");
 	
 	struct qbe_value cmpres = mkqtmp(ctx, &qbe_word, ".%d");
 	struct qbe_value zero = constl(0);
 	pushi(ctx->current, &cmpres, Q_CNEL, &olen, &zero, NULL);
 	pushi(ctx->current, NULL, Q_JNZ, &cmpres, &bnonzero, &bzero, NULL);
 	push(&ctx->current->body, &lnonzero);
 	
 	// get the destination
 	struct qbe_value odata = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 	pushi(ctx->current, &odata, Q_LOADL, &qobj, NULL);
 	
 	// get the source
 	struct gen_value val = gen_expr(ctx, expr->assign.value);
 	struct qbe_value qval = mkqval(ctx, &val);
 	struct qbe_value vdata = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 	pushi(ctx->current, &vdata, Q_LOADL, &qval, NULL);
 	
 	// copy the first item
 	const struct type *sltype = expr->assign.object->result->array.members;
 	enum qbe_instr store = store_for_type(ctx, sltype);
 	pushi(ctx->current, NULL, store, &vdata, &odata, NULL);
 	
 	// perform the copy minus the first element
 	struct qbe_value isize = constl(sltype->size);
 	struct qbe_value next = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 	pushi(ctx->current, &next, Q_ADD, &odata, &isize, NULL);
 	struct qbe_value rtmemcpy = mkrtfunc(ctx, "rt.memcpy");
 	struct qbe_value one = constl(1);
 	pushi(ctx->current, &olen, Q_SUB, &olen, &one, NULL);
 	pushi(ctx->current, &olen, Q_MUL, &olen, &isize, NULL);
 	pushi(ctx->current, NULL, Q_CALL, &rtmemcpy, &next, &odata, &olen, NULL);
 	
 	push(&ctx->current->body, &lzero);
 	
 	return gv_void;
 }
 
 static struct gen_value
 gen_expr_assign_slice(struct gen_context *ctx, const struct expression *expr)
 {
 	const struct type *vtype = type_dealias(expr->assign.value->result);
 	if (vtype->storage == STORAGE_ARRAY && vtype->array.expandable) {
 		return gen_expr_assign_slice_expandable(ctx, expr);
 	}
 
 	struct gen_value obj = gen_expr(ctx, expr->assign.object);
 	struct gen_value val = gen_expr(ctx, expr->assign.value);
 	struct qbe_value qobj = mkqval(ctx, &obj);
 	struct qbe_value qval = mkqval(ctx, &val);
 	struct qbe_value step = constl(ctx->arch.ptr->size);
 
 	struct qbe_value ptr = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 	struct qbe_value olen = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 	struct qbe_value vlen = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 
 	pushi(ctx->current, &ptr, Q_ADD, &qobj, &step, NULL);
 	pushi(ctx->current, &olen, Q_LOADL, &ptr, NULL);
 	pushi(ctx->current, &ptr, Q_ADD, &qval, &step, NULL);
 	pushi(ctx->current, &vlen, Q_LOADL, &ptr, NULL);
 
 	struct qbe_statement linvalid, lvalid;
 	struct qbe_value binvalid = mklabel(ctx, &linvalid, ".%d");
 	struct qbe_value bvalid = mklabel(ctx, &lvalid, ".%d");
 	struct qbe_value tmp = mkqtmp(ctx, &qbe_long, ".%d");
 	pushi(ctx->current, &tmp, Q_CEQL, &olen, &vlen, NULL);
 	pushi(ctx->current, NULL, Q_JNZ, &tmp, &bvalid, &binvalid, NULL);
 	push(&ctx->current->body, &linvalid);
 	gen_fixed_abort(ctx, expr->loc, ABORT_OOB);
 	push(&ctx->current->body, &lvalid);
 
 	struct qbe_value rtmemmove = mkrtfunc(ctx, "rt.memmove");
 	struct qbe_value optr = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 	struct qbe_value vptr = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 	pushi(ctx->current, &optr, Q_LOADL, &qobj, NULL);
 	pushi(ctx->current, &vptr, Q_LOADL, &qval, NULL);
 	tmp = constl(expr->assign.object->result->array.members->size);
 	pushi(ctx->current, &olen, Q_MUL, &olen, &tmp, NULL);
 	pushi(ctx->current, NULL, Q_CALL, &rtmemmove, &optr, &vptr, &olen, NULL);
 
 	return gv_void;
 }
 
 static struct gen_value
 gen_expr_assign(struct gen_context *ctx, const struct expression *expr)
 {
 	struct expression *object = expr->assign.object;
 	struct expression *value = expr->assign.value;
 	if (object->type == EXPR_SLICE) {
 		return gen_expr_assign_slice(ctx, expr);
 	}
 
 	struct gen_value obj;
 	switch (object->type) {
 	case EXPR_ACCESS:
 		obj = gen_expr_access_addr(ctx, object);
 		break;
 	case EXPR_UNARITHM:
 		assert(object->unarithm.op == UN_DEREF); // Invariant
 		obj = gen_expr(ctx, object->unarithm.operand);
 		assert(type_dealias(obj.type)->storage == STORAGE_POINTER);
 		obj.type = type_dealias(obj.type)->pointer.referent;
 		break;
 	default:
 		abort(); // Invariant
 	}
 	if (expr->assign.op == BIN_LEQUAL) {
 		gen_store(ctx, obj, gen_expr(ctx, value));
 	} else if (expr->assign.op == BIN_LAND || expr->assign.op == BIN_LOR) {
 		struct qbe_statement lrval, lshort;
 		struct qbe_value brval = mklabel(ctx, &lrval, ".%d");
 		struct qbe_value bshort = mklabel(ctx, &lshort, ".%d");
 		struct gen_value load = gen_load(ctx, obj);
 		struct qbe_value qload = mkqval(ctx, &load);
 		if (expr->binarithm.op == BIN_LAND) {
 			pushi(ctx->current, NULL, Q_JNZ, &qload, &brval,
 				&bshort, NULL);
 		} else {
 			pushi(ctx->current, NULL, Q_JNZ, &qload, &bshort,
 				&brval, NULL);
 		}
 		push(&ctx->current->body, &lrval);
 		gen_expr_at(ctx, value, obj);
 		if (!expr->binarithm.rvalue->terminates) {
 			pushi(ctx->current, NULL, Q_JMP, &bshort, NULL);
 		}
 		push(&ctx->current->body, &lshort);
 	} else {
 		struct gen_value lvalue = gen_load(ctx, obj);
 		struct gen_value rvalue = gen_expr(ctx, value);
 		struct qbe_value qlval = mkqval(ctx, &lvalue);
 		struct qbe_value qrval = mkqval(ctx, &rvalue);
 		enum qbe_instr instr = binarithm_for_op(ctx,
 			expr->assign.op, lvalue.type);
 		pushi(ctx->current, &qlval, instr, &qlval, &qrval, NULL);
 		gen_store(ctx, obj, lvalue);
 	}
 
 	return gv_void;
 }
 
 static struct qbe_value
 extend(struct gen_context *ctx, struct qbe_value v, const struct type *type)
 {
 	enum qbe_instr op;
 	switch (type->size) {
 	case 1:
 		op = type_is_signed(type) ? Q_EXTSB : Q_EXTUB;
 		break;
 	case 2:
 		op = type_is_signed(type) ? Q_EXTSH : Q_EXTUH;
 		break;
 	default:
 		return v;
 	}
 
 	struct qbe_value temp = mkqtmp(ctx, &qbe_word, "ext.%d");
 	pushi(ctx->current, &temp, op, &v, NULL);
 	return temp;
 }
 
 static struct gen_value
 gen_expr_binarithm(struct gen_context *ctx, const struct expression *expr)
 {
 	const struct type *ltype = type_dealias(expr->binarithm.lvalue->result);
 	const struct type *rtype = type_dealias(expr->binarithm.rvalue->result);
 	struct gen_value result = mkgtemp(ctx, expr->result, ".%d");
 	struct qbe_value qresult = mkqval(ctx, &result);
 
 	if (expr->binarithm.op == BIN_LAND || expr->binarithm.op == BIN_LOR) {
 		struct qbe_statement lrval, lshort;
 		struct qbe_value brval = mklabel(ctx, &lrval, ".%d");
 		struct qbe_value bshort = mklabel(ctx, &lshort, ".%d");
 		struct gen_value lval = gen_expr(ctx, expr->binarithm.lvalue);
 		struct qbe_value qlval = mkqval(ctx, &lval);
 		pushi(ctx->current, &qresult, Q_COPY, &qlval, NULL);
 		if (expr->binarithm.op == BIN_LAND) {
 			pushi(ctx->current, NULL, Q_JNZ, &qresult, &brval,
 				&bshort, NULL);
 		} else {
 			pushi(ctx->current, NULL, Q_JNZ, &qresult, &bshort,
 				&brval, NULL);
 		}
 		push(&ctx->current->body, &lrval);
 		struct gen_value rval = gen_expr(ctx, expr->binarithm.rvalue);
 		struct qbe_value qrval = mkqval(ctx, &rval);
 		pushi(ctx->current, &qresult, Q_COPY, &qrval, NULL);
 		if (!expr->binarithm.rvalue->terminates) {
 			pushi(ctx->current, NULL, Q_JMP, &bshort, NULL);
 		}
 		push(&ctx->current->body, &lshort);
 		return result;
 	}
 
 	struct gen_value lvalue = gen_expr(ctx, expr->binarithm.lvalue);
 	struct gen_value rvalue = gen_expr(ctx, expr->binarithm.rvalue);
 	struct qbe_value qlval = mkqval(ctx, &lvalue);
 	struct qbe_value qrval = mkqval(ctx, &rvalue);
 
 	switch (expr->binarithm.op) {
 	case BIN_GREATER:
 	case BIN_GREATEREQ:
 	case BIN_LEQUAL:
 	case BIN_LESS:
 	case BIN_LESSEQ:
 	case BIN_NEQUAL:
 		qlval = extend(ctx, qlval, ltype);
 		qrval = extend(ctx, qrval, rtype);
 		break;
 	default:
 		break;
 	}
 
 	assert((ltype->storage == STORAGE_STRING) == (rtype->storage == STORAGE_STRING));
 	if (ltype->storage == STORAGE_STRING) {
 		struct qbe_value rtfunc = mkrtfunc(ctx, "rt.strcmp");
 		pushi(ctx->current, &qresult, Q_CALL,
 			&rtfunc, &qlval, &qrval, NULL);
 		if (expr->binarithm.op == BIN_NEQUAL) {
 			struct qbe_value one = constl(1);
 			pushi(ctx->current, &qresult, Q_XOR, &qresult, &one, NULL);
 		} else {
 			assert(expr->binarithm.op == BIN_LEQUAL);
 		}
 		return result;
 	}
 	enum qbe_instr instr = binarithm_for_op(ctx, expr->binarithm.op,
 		expr->binarithm.lvalue->result);
 	pushi(ctx->current, &qresult, instr, &qlval, &qrval, NULL);
 	return result;
 }
 
 static void
 gen_expr_binding_unpack_static(struct gen_context *ctx,
 	const struct expression_binding *binding)
 {
 	assert(binding->object == NULL);
 
 	struct tuple_constant *tupleconst =
 		binding->initializer->constant.tuple;
 
 	for (const struct binding_unpack *unpack = binding->unpack;
 			unpack; unpack = unpack->next) {
 		if (unpack->object == NULL) {
 			goto done;
 		}
 		assert(unpack->object->otype == O_DECL);
 
 		struct declaration decl = {
 			.type = DECL_GLOBAL,
 			.ident = unpack->object->ident,
 			.global = {
 				.type = unpack->object->type,
 				.value = tupleconst->value,
 			},
 		};
 		gen_global_decl(ctx, &decl);
 
 done:
 		tupleconst = tupleconst->next;
 	}
 }
 
 static void
 gen_expr_binding_unpack(struct gen_context *ctx,
 	const struct expression_binding *binding)
 {
 	assert(binding->object == NULL);
 
 	const struct type *type = binding->initializer->result;
 	char *tuple_name = gen_name(&ctx->id, "tupleunpack.%d");
 	struct gen_value tuple_gv = {
 		.kind = GV_TEMP,
 		.type = type,
 		.name = tuple_name,
 	};
 	struct qbe_value tuple_qv = mklval(ctx, &tuple_gv);
 	struct qbe_value sz = constl(type->size);
 	enum qbe_instr alloc = alloc_for_align(type->align);
 	pushprei(ctx->current, &tuple_qv, alloc, &sz, NULL);
 
 	gen_expr_at(ctx, binding->initializer, tuple_gv);
 
 	for (const struct binding_unpack *unpack = binding->unpack;
 			unpack; unpack = unpack->next) {
 		if (unpack->object == NULL) {
 			continue;
 		}
 		assert(unpack->object->otype != O_DECL);
 
 		const struct type *type = unpack->object->type;
 		struct gen_value item_gv = {
 			.kind = GV_TEMP,
 			.type = type,
 			.name = gen_name(&ctx->id, "binding.%d"),
 		};
 		struct gen_binding *gb = xcalloc(1, sizeof(struct gen_binding));
 		gb->value = item_gv;
 		gb->object = unpack->object;
 		gb->next = ctx->bindings;
 		ctx->bindings = gb;
 		struct qbe_value item_qv = mklval(ctx, &gb->value);
 		struct qbe_value offs = constl(unpack->offset);
 		pushprei(ctx->current, &item_qv, Q_ADD, &tuple_qv, &offs, NULL);
 	}
 }
 
 static struct gen_value
 gen_expr_binding(struct gen_context *ctx, const struct expression *expr)
 {
 	for (const struct expression_binding *binding = &expr->binding;
 			binding; binding = binding->next) {
 		if (binding->unpack) {
 			if (binding->unpack->object->otype == O_DECL) {
 				gen_expr_binding_unpack_static(ctx, binding);
 			} else {
 				gen_expr_binding_unpack(ctx, binding);
 			}
 			continue;
 		}
 
 		if (binding->object->otype == O_DECL) {
 			// static binding
 			struct declaration decl = {
 				.type = DECL_GLOBAL,
 				.ident = binding->object->ident,
 				.global = {
 					.type = binding->object->type,
 					.value = binding->initializer,
 				},
 			};
 			gen_global_decl(ctx, &decl);
 			continue;
 		}
 
 		const struct type *type = binding->object->type;
 		struct gen_binding *gb = xcalloc(1, sizeof(struct gen_binding));
 		gb->value.kind = GV_TEMP;
 		gb->value.type = type;
 		gb->value.name = gen_name(&ctx->id, "binding.%d");
 		gb->object = binding->object;
 		gb->next = ctx->bindings;
 		ctx->bindings = gb;
 
 		struct qbe_value qv = mklval(ctx, &gb->value);
 		struct qbe_value sz = constl(type->size);
 		enum qbe_instr alloc = alloc_for_align(type->align);
 		pushprei(ctx->current, &qv, alloc, &sz, NULL);
 		gen_expr_at(ctx, binding->initializer, gb->value);
 	}
 	return gv_void;
 }
 
 static struct gen_value
 gen_expr_control(struct gen_context *ctx, const struct expression *expr)
 {
 	struct gen_scope *scope = gen_scope_lookup(ctx, expr->control.scope);
 
 	if (expr->control.value) {
 		struct gen_value result = gen_expr_with(ctx,
 			expr->control.value, scope->out);
 		branch_copyresult(ctx, result,
 			scope->result, scope->out);
 	}
 
 	struct gen_scope *deferred = ctx->scope;
 	while (deferred != NULL) {
 		gen_defers(ctx, deferred);
 		if (deferred == scope) {
 			break;
 		}
 		deferred = deferred->parent;
 	}
 
 	switch (expr->type) {
 	case EXPR_BREAK:
 		assert(scope->scope->class == SCOPE_LOOP);
 		pushi(ctx->current, NULL, Q_JMP, scope->end, NULL);
 		break;
 	case EXPR_CONTINUE:
 		assert(scope->scope->class == SCOPE_LOOP);
 		pushi(ctx->current, NULL, Q_JMP, scope->after, NULL);
 		break;
 	case EXPR_YIELD:
 		assert(scope->scope->class == SCOPE_COMPOUND);
 		pushi(ctx->current, NULL, Q_JMP, scope->end, NULL);
 		break;
 	default: abort(); // Invariant
 	}
 	return gv_void;
 }
 
 static struct gen_value
 gen_expr_call(struct gen_context *ctx, const struct expression *expr)
 {
 	struct gen_value lvalue = gen_expr(ctx, expr->call.lvalue);
 	lvalue = gen_autoderef(ctx, lvalue);
 
 	const struct type *rtype = type_dealias(lvalue.type);
 	assert(rtype->storage == STORAGE_FUNCTION);
 
 	if (rtype->func.flags & FN_NORETURN) {
 		for (struct gen_scope *scope = ctx->scope; scope;
 				scope = scope->parent) {
 			gen_defers(ctx, scope);
 		}
 	}
 
 	struct qbe_statement call = {
 		.type = Q_INSTR,
 		.instr = Q_CALL,
 	};
 	struct gen_value rval = gv_void;
 	if (type_dealias(rtype->func.result)->storage != STORAGE_VOID) {
 		rval = mkgtemp(ctx, rtype->func.result, "returns.%d");
 		call.out = xcalloc(1, sizeof(struct qbe_value));
 		*call.out = mkqval(ctx, &rval);
 		call.out->type = qtype_lookup(ctx, rtype->func.result, false);
 	}
 
 	bool cvar = false;
 	struct type_func_param *param = rtype->func.params;
 	struct qbe_arguments *args, **next = &call.args;
 	args = *next = xcalloc(1, sizeof(struct qbe_arguments));
 	args->value = mkqval(ctx, &lvalue);
 	next = &args->next;
 	for (struct call_argument *carg = expr->call.args;
 			carg; carg = carg->next) {
 		args = *next = xcalloc(1, sizeof(struct qbe_arguments));
 		struct gen_value arg = gen_expr(ctx, carg->value);
 		args->value = mkqval(ctx, &arg);
 		args->value.type = qtype_lookup(ctx, carg->value->result, false);
 		next = &args->next;
 		if (param) {
 			param = param->next;
 		}
 		if (!param && !cvar && rtype->func.variadism == VARIADISM_C) {
 			cvar = true;
 			args = *next = xcalloc(1, sizeof(struct qbe_arguments));
 			args->value.kind = QV_VARIADIC;
 			next = &args->next;
 		}
 	}
 	push(&ctx->current->body, &call);
 
 	return rval;
 }
 
 static struct gen_value gen_expr_cast(struct gen_context *ctx,
 		const struct expression *expr);
 
 static struct gen_value gen_subset_match_tests(struct gen_context *ctx,
 	struct qbe_value bmatch, struct qbe_value bnext,
 	struct qbe_value tag, const struct type *type);
 
 static struct gen_value gen_nested_match_tests(struct gen_context *ctx,
 		struct gen_value object, struct qbe_value bmatch,
 		struct qbe_value bnext, struct qbe_value tag,
 		const struct type *type);
 
 static struct gen_value
 gen_type_assertion_or_test(struct gen_context *ctx, const struct expression *expr,
 		struct gen_value base)
 {
 	assert(expr->cast.kind == C_TEST || expr->cast.kind == C_ASSERTION);
 	const struct type *want = expr->cast.secondary;
 	struct qbe_value tag = mkqtmp(ctx,
 		qtype_lookup(ctx, &builtin_type_uint, false), ".%d");
 	enum qbe_instr load = load_for_type(ctx, &builtin_type_uint);
 	struct qbe_value qbase = mkqval(ctx, &base);
 	pushi(ctx->current, &tag, load, &qbase, NULL);
 
 	struct qbe_statement failedl, passedl;
 	struct qbe_value bfailed, bpassed = mklabel(ctx, &passedl, "passed.%d");
 	if (expr->cast.kind == C_ASSERTION) {
 		bfailed = mklabel(ctx, &failedl, "failed.%d");
 	} else {
 		bfailed = bpassed;
 	}
 	struct gen_value result = {0};
 	if (tagged_select_subtype(expr->cast.value->result, want, true)) {
 		result = gen_nested_match_tests(ctx, base, bpassed,
 				bfailed, tag, want);
 	} else if (tagged_subset_compat(expr->cast.value->result, want)) {
 		result = gen_subset_match_tests(ctx, bpassed, bfailed, tag,
 				type_dealias(want));
 	} else {
 		abort();
 	}
 
 	if (expr->cast.kind == C_ASSERTION) {
 		push(&ctx->current->body, &failedl);
 		gen_fixed_abort(ctx, expr->loc, ABORT_TYPE_ASSERTION);
 	}
 	push(&ctx->current->body, &passedl);
 	return result;
 }
 
 static void
 gen_expr_cast_slice_at(struct gen_context *ctx,
 	const struct expression *expr, struct gen_value out)
 {
 	const struct type *to = expr->result,
 		*from = type_dealias(expr->cast.value->result);
 	if (from->storage == STORAGE_POINTER) {
 		from = type_dealias(from->pointer.referent);
 	}
 	assert(from->storage == STORAGE_ARRAY);
 	assert(from->array.length != SIZE_UNDEFINED);
 
 	enum qbe_instr store = store_for_type(ctx, &builtin_type_size);
 	struct qbe_value base = mklval(ctx, &out);
 	struct qbe_value sz = constl(to->size);
 	if (from->array.length == 0) {
 		struct qbe_value tmp = constl(0);
 		pushi(ctx->current, NULL, store, &tmp, &base, NULL);
 	} else {
 		struct gen_value value = gen_expr(ctx, expr->cast.value);
 		struct qbe_value qvalue = mkqval(ctx, &value);
 		pushi(ctx->current, NULL, store, &qvalue, &base, NULL);
 	}
 	struct qbe_value qptr = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 	sz = constl(builtin_type_size.size);
 	struct qbe_value ln = constl(from->array.length);
 	pushi(ctx->current, &qptr, Q_ADD, &base, &sz, NULL);
 	pushi(ctx->current, NULL, store, &ln, &qptr, NULL);
 	pushi(ctx->current, &qptr, Q_ADD, &qptr, &sz, NULL);
 	pushi(ctx->current, NULL, store, &ln, &qptr, NULL);
 }
 
 // Returns true if object's storage can be interpreted as want.
 static bool
 tagged_align_compat(const struct type *object, const struct type *want)
 {
 	assert(type_dealias(object)->storage == STORAGE_TAGGED);
 	assert(type_dealias(want)->storage == STORAGE_TAGGED);
 	return object->align == want->align
 		|| want->size == builtin_type_uint.size;
 }
 
 static void
 gen_expr_cast_tagged_at(struct gen_context *ctx,
 	const struct expression *expr, struct gen_value out)
 {
 	assert(expr->type == EXPR_CAST);
 	const struct type *to = expr->result, *from = expr->cast.value->result;
 	const struct type *subtype = tagged_select_subtype(to, from, true);
 
 	if (!subtype && tagged_align_compat(from, to)) {
 		// Case 1: from is a union whose members are a subset or
 		// superset of to, and the alignment matches, so we can just
 		// interpret values of type 'from' as if it were of type 'to'
 		struct gen_value out2 = out;
 		out2.type = from;
 		gen_expr_at(ctx, expr->cast.value, out2);
 		if (expr->cast.kind == C_ASSERTION) {
 			gen_type_assertion_or_test(ctx, expr, out2);
 		}
 	} else if (!subtype) {
 		// Case 2: like case 1, but with an alignment mismatch; more
 		// work is required.
 		struct gen_value value = gen_expr(ctx, expr->cast.value);
 		struct qbe_value qval = mkqval(ctx, &value);
 		if (expr->cast.kind == C_ASSERTION) {
 			gen_type_assertion_or_test(ctx, expr, value);
 		}
 		struct qbe_value qout = mkqval(ctx, &out);
 		struct qbe_value tag = mkqtmp(ctx,
 			qtype_lookup(ctx, &builtin_type_uint, false), "tag.%d");
 		enum qbe_instr load = load_for_type(ctx, &builtin_type_uint);
 		enum qbe_instr store = store_for_type(ctx, &builtin_type_uint);
 		pushi(ctx->current, &tag, load, &qval, NULL);
 		pushi(ctx->current, NULL, store, &tag, &qout, NULL);
 		if (to->size == builtin_type_uint.size ||
 				from->size == builtin_type_uint.size) {
 			// No data area to copy
 			return;
 		}
 
 		subtype = tagged_subset_compat(to, from) ? from : to;
 		const struct type *innertype = type_store_tagged_to_union(
 				ctx->store, type_dealias(subtype));
 		struct gen_value iout = mkgtemp(ctx, innertype, ".%d");
 		struct gen_value ival = mkgtemp(ctx, innertype, ".%d");
 		struct qbe_value qiout = mkqval(ctx, &iout);
 		struct qbe_value qival = mkqval(ctx, &ival);
 		struct qbe_value offs = constl(to->align);
 		pushi(ctx->current, &qiout, Q_ADD, &qout, &offs, NULL);
 		offs = constl(from->align);
 		pushi(ctx->current, &qival, Q_ADD, &qval, &offs, NULL);
 		gen_copy_aligned(ctx, iout, ival);
 	} else {
 		// Case 3: from is a member of to
 		assert(subtype == from); // Lowered by check
 		struct qbe_value qout = mkqval(ctx, &out);
 		struct qbe_value id = constw(subtype->id);
 		enum qbe_instr store = store_for_type(ctx, &builtin_type_uint);
 		pushi(ctx->current, NULL, store, &id, &qout, NULL);
 		if (subtype->size == 0) {
 			gen_expr(ctx, expr->cast.value); // side-effects
 			return;
 		}
 
 		struct gen_value storage = mkgtemp(ctx, subtype, ".%d");
 		struct qbe_value qstor = mklval(ctx, &storage);
 		struct qbe_value offs = constl(to->align);
 		pushi(ctx->current, &qstor, Q_ADD, &qout, &offs, NULL);
 		gen_expr_at(ctx, expr->cast.value, storage);
 	}
 }
 
 static bool
 cast_prefers_at(const struct expression *expr)
 {
 	const struct type *to = expr->result, *from = expr->cast.value->result;
 	if (expr->cast.kind == C_TEST) {
 		return false;
 	}
 	// tagged => *; subtype compatible
 	if (type_dealias(from)->storage == STORAGE_TAGGED
 			&& tagged_select_subtype(from, to, true)) {
 		return false;
 	}
 	// * => tagged
 	if (type_dealias(to)->storage == STORAGE_TAGGED) {
 		return true;
 	}
 	// array => array
 	if (type_dealias(to)->storage == STORAGE_ARRAY
 			&& type_dealias(from)->storage == STORAGE_ARRAY) {
 		return true;
 	}
 	// array => slice
 	if (type_dealias(to)->storage == STORAGE_SLICE) {
 		switch (type_dealias(from)->storage) {
 		case STORAGE_ARRAY:
 			return true;
 		case STORAGE_POINTER:
 			from = type_dealias(from)->pointer.referent;
 			return type_dealias(from)->storage == STORAGE_ARRAY;
 		default:
 			return false;
 		}
 	}
 	return false;
 }
 
 static void
 gen_expr_cast_array_at(struct gen_context *ctx,
 	const struct expression *expr, struct gen_value out)
 {
 	const struct type *typeout = type_dealias(expr->result);
 	const struct type *typein = type_dealias(expr->cast.value->result);
 	gen_expr_at(ctx, expr->cast.value, out);
 	if (!typein->array.expandable) {
 		return;
 	}
 
 	assert(typein->array.length != SIZE_UNDEFINED
 			&& typeout->array.length != SIZE_UNDEFINED);
 	assert(typeout->array.length >= typein->array.length);
 
 	const struct type *membtype = typein->array.members;
 	size_t remain = typeout->array.length - typein->array.length;
 
 	struct qbe_value base = mkqval(ctx, &out);
 	struct qbe_value offs = constl((typein->array.length - 1) * membtype->size);
 	struct gen_value next = mkgtemp(ctx, membtype, ".%d");
 	struct qbe_value ptr = mklval(ctx, &next);
 	struct gen_value item = mkgtemp(ctx, membtype, "item.%d");
 	struct qbe_value qitem = mklval(ctx, &item);
 	pushi(ctx->current, &qitem, Q_ADD, &base, &offs, NULL);
 
 	if (remain * membtype->size <= 128) {
 		struct gen_value last = gen_load(ctx, item);
 		for (size_t n = typein->array.length; n < typeout->array.length; ++n) {
 			struct qbe_value offs = constl(n * membtype->size);
 			pushi(ctx->current, &ptr, Q_ADD, &base, &offs, NULL);
 			gen_store(ctx, next, last);
 		}
 		return;
 	}
 
 	offs = constl(typein->array.length * membtype->size);
 	pushi(ctx->current, &ptr, Q_ADD, &base, &offs, NULL);
 
 	struct qbe_value rtfunc = mkrtfunc(ctx, "rt.memcpy");
 	struct qbe_value dtemp = mklval(ctx, &next);
 	struct qbe_value stemp = mklval(ctx, &item);
 	struct qbe_value sz = constl(remain * membtype->size);
 	pushi(ctx->current, NULL, Q_CALL, &rtfunc, &dtemp, &stemp, &sz, NULL);
 }
 
 static void
 gen_expr_cast_at(struct gen_context *ctx,
 	const struct expression *expr, struct gen_value out)
 {
 	if (!cast_prefers_at(expr)) {
 		struct gen_value result = gen_expr_cast(ctx, expr);
 		if (!expr->terminates) {
 			gen_store(ctx, out, result);
 		}
 		return;
 	}
 
 	if (expr->cast.lowered) {
 		pushc(ctx->current, "gen lowered cast");
 	}
 
 	const struct type *to = expr->result;
 	switch (type_dealias(to)->storage) {
 	case STORAGE_SLICE:
 		gen_expr_cast_slice_at(ctx, expr, out);
 		break;
 	case STORAGE_TAGGED:
 		gen_expr_cast_tagged_at(ctx, expr, out);
 		break;
 	case STORAGE_ARRAY:
 		gen_expr_cast_array_at(ctx, expr, out);
 		break;
 	default: abort(); // Invariant
 	}
 }
 
 static struct qbe_value nested_tagged_offset(const struct type *tu,
 		const struct type *targed);
 
 static struct gen_value
 gen_expr_cast(struct gen_context *ctx, const struct expression *expr)
 {
 	const struct type *to = expr->cast.secondary,
 		*from = expr->cast.value->result;
 	if (expr->cast.kind != C_CAST) {
 		bool is_valid_tagged, is_valid_pointer;
 		is_valid_tagged = type_dealias(from)->storage == STORAGE_TAGGED
 				&& (tagged_select_subtype(from, to, true)
 				|| tagged_subset_compat(from, to));
 		is_valid_pointer = type_dealias(from)->storage == STORAGE_POINTER
 				&& (type_dealias(to)->storage == STORAGE_POINTER
 				|| type_dealias(to)->storage == STORAGE_NULL);
 		assert(is_valid_tagged || is_valid_pointer);
 		if (expr->cast.kind == C_TEST && is_valid_tagged) {
 			return gen_type_assertion_or_test(ctx, expr,
 					gen_expr(ctx, expr->cast.value));
 		}
 	}
 
 	if (cast_prefers_at(expr)) {
 		struct gen_value out = mkgtemp(ctx, expr->result, "object.%d");
 		struct qbe_value base = mkqval(ctx, &out);
 		struct qbe_value sz = constl(expr->result->size);
 		enum qbe_instr alloc = alloc_for_align(expr->result->align);
 		pushprei(ctx->current, &base, alloc, &sz, NULL);
 		gen_expr_cast_at(ctx, expr, out);
 		return out;
 	}
 
 	if (expr->cast.lowered) {
 		pushc(ctx->current, "gen lowered cast");
 	}
 
 	// Special cases
 	bool want_null = false;
 	switch (type_dealias(to)->storage) {
 	case STORAGE_NULL:
 		want_null = true;
 		// fallthrough
 	case STORAGE_POINTER:
 		if (type_dealias(from)->storage == STORAGE_SLICE) {
 			struct gen_value value = gen_expr(ctx, expr->cast.value);
 			value.type = to;
 			return gen_load(ctx, value);
 		}
 		if (type_dealias(from)->storage != STORAGE_POINTER) {
 			break;
 		}
 
 		struct gen_value val = gen_expr(ctx, expr->cast.value);
 		struct qbe_value qval = mkqval(ctx, &val);
 		struct qbe_value zero = constl(0);
 		enum qbe_instr compare = want_null ? Q_CEQL : Q_CNEL;
 		if (expr->cast.kind == C_TEST) {
 			struct gen_value out =
 				mkgtemp(ctx, &builtin_type_bool, ".%d");
 			struct qbe_value qout = mkqval(ctx, &out);
 
 			pushi(ctx->current, &qout, compare, &qval, &zero, NULL);
 			return out;
 		} else if (expr->cast.kind == C_ASSERTION) {
 			struct qbe_statement failedl, passedl;
 			struct qbe_value bfailed =
 				mklabel(ctx, &failedl, "failed.%d");
 			struct qbe_value bpassed =
 				mklabel(ctx, &passedl, "passed.%d");
 
 			struct qbe_value cmpres = mkqtmp(ctx, &qbe_word, ".%d");
 			pushi(ctx->current, &cmpres, compare, &qval, &zero, NULL);
 			pushi(ctx->current, NULL, Q_JNZ, &cmpres,
 				&bpassed, &bfailed, NULL);
 			push(&ctx->current->body, &failedl);
 			gen_fixed_abort(ctx, expr->loc, ABORT_TYPE_ASSERTION);
 
 			push(&ctx->current->body, &passedl);
 			if (want_null) {
 				return (struct gen_value){
 					.kind = GV_CONST,
 					.type = &builtin_type_null,
 					.lval = 0,
 				};
 			}
 		}
 		val.type = to;
 		return val;
 	case STORAGE_VOID:
 		gen_expr(ctx, expr->cast.value); // Side-effects
 		return gv_void;
 	default: break;
 	}
 
 	// Special case: tagged => non-tagged
 	if (type_dealias(from)->storage == STORAGE_TAGGED) {
 		struct gen_value value = gen_expr(ctx, expr->cast.value);
 		struct qbe_value base = mkcopy(ctx, &value, ".%d");
 		if (expr->cast.kind == C_ASSERTION) {
 			gen_type_assertion_or_test(ctx, expr, value);
 		}
 
 		struct qbe_value align = nested_tagged_offset(
 				expr->cast.value->result, expr->cast.secondary);
 		pushi(ctx->current, &base, Q_ADD, &base, &align, NULL);
 		struct gen_value storage = (struct gen_value){
 			.kind = GV_TEMP,
 			.type = to,
 			.name = base.name,
 		};
 		return gen_load(ctx, storage);
 	}
 
 	// Special case: no conversion required
 	if (type_dealias(to)->storage == type_dealias(from)->storage
 			&& to->size == from->size) {
 		struct gen_value value = gen_expr(ctx, expr->cast.value);
 		value.type = to;
 		return value;
 	}
 
 	struct gen_value value = gen_expr(ctx, expr->cast.value);
 	struct qbe_value qvalue = mkqval(ctx, &value);
 	struct gen_value result = mkgtemp(ctx, expr->result, "cast.%d");
 	struct qbe_value qresult = mkqval(ctx, &result);
 	struct gen_value intermediate;
 	struct qbe_value qintermediate;
 
 	from = lower_const(from, NULL);
 
 	enum qbe_instr op;
 	bool is_signed = type_is_signed(from);
 	enum type_storage fstor = type_dealias(from)->storage,
 		tstor = type_dealias(to)->storage;
 	switch (tstor) {
 	case STORAGE_CHAR:
 	case STORAGE_ENUM:
 	case STORAGE_U8:
 	case STORAGE_I8:
 	case STORAGE_I16:
 	case STORAGE_U16:
 	case STORAGE_I32:
 	case STORAGE_U32:
 	case STORAGE_INT:
 	case STORAGE_UINT:
 	case STORAGE_I64:
 	case STORAGE_U64:
 	case STORAGE_UINTPTR:
 	case STORAGE_RUNE:
 	case STORAGE_SIZE:
 		if (type_is_integer(from) && to->size <= from->size) {
 			op = Q_COPY;
 		} else if (type_is_integer(from) && to->size > from->size) {
 			switch (from->size) {
 			case 4: op = is_signed ? Q_EXTSW : Q_EXTUW; break;
 			case 2: op = is_signed ? Q_EXTSH : Q_EXTUH; break;
 			case 1: op = is_signed ? Q_EXTSB : Q_EXTUB; break;
 			default: abort(); // Invariant
 			}
 		} else if (fstor == STORAGE_POINTER || fstor == STORAGE_NULL) {
 			assert(tstor == STORAGE_UINTPTR);
 			op = Q_COPY;
 		} else if (fstor == STORAGE_RUNE) {
 			op = Q_COPY;
 		} else if (type_is_float(from)) {
 			if (type_is_signed(to)) {
 				switch (fstor) {
 				case STORAGE_F32: op = Q_STOSI; break;
 				case STORAGE_F64: op = Q_DTOSI; break;
 				default: abort(); // Invariant
 				}
 			} else {
 				switch (fstor) {
 				case STORAGE_F32: op = Q_STOUI; break;
 				case STORAGE_F64: op = Q_DTOUI; break;
 				default: abort(); // Invariant
 				}
 			}
 		} else {
 			abort(); // Invariant
 		}
 		pushi(ctx->current, &qresult, op, &qvalue, NULL);
 		break;
 	case STORAGE_F32:
 	case STORAGE_F64:
 		if (type_is_float(from) && from->size == to->size) {
 			op = Q_COPY;
 		} else if (type_is_float(from) && to->size < from->size) {
 			op = Q_TRUNCD;
 		} else if (type_is_float(from) && to->size > from->size) {
 			op = Q_EXTS;
 		} else if (type_is_integer(from)) {
 			if (type_is_signed(from)) {
 				switch (from->size) {
 				case 1:
 				case 2:
 					intermediate = mkgtemp(ctx,
 						&builtin_type_i32, "cast.%d");
 					qintermediate = mkqval(ctx, &intermediate);
 					pushi(ctx->current, &qintermediate,
 						from->size == 1? Q_EXTSB : Q_EXTSH,
 						&qvalue, NULL);
 					qvalue = qintermediate;
 					/* fallthrough */
 				case 4:
 					op = Q_SWTOF;
 					break;
 				case 8:
 					op = Q_SLTOF;
 					break;
 				default: abort(); // Invariant
 				}
 			} else {
 				switch (from->size) {
 				case 1:
 				case 2:
 					intermediate = mkgtemp(ctx,
 						&builtin_type_i32, "cast.%d");
 					qintermediate = mkqval(ctx, &intermediate);
 					pushi(ctx->current, &qintermediate,
 						from->size == 1? Q_EXTUB : Q_EXTUH,
 						&qvalue, NULL);
 					qvalue = qintermediate;
 					/* fallthrough */
 				case 4:
 					op = Q_UWTOF;
 					break;
 				case 8:
 					op = Q_ULTOF;
 					break;
 				default: abort(); // Invariant
 				}
 			}
 		} else {
 			abort(); // Invariant
 		}
 		pushi(ctx->current, &qresult, op, &qvalue, NULL);
 		break;
 	case STORAGE_NULL:
 	case STORAGE_POINTER:
 		pushi(ctx->current, &qresult, Q_COPY, &qvalue, NULL);
 		break;
 	case STORAGE_ARRAY:
 		assert(from->storage == STORAGE_ARRAY);
 		pushi(ctx->current, &qresult, Q_COPY, &qvalue, NULL);
 		break;
 	case STORAGE_SLICE:
 		assert(from->storage == STORAGE_SLICE);
 		pushi(ctx->current, &qresult, Q_COPY, &qvalue, NULL);
 		break;
 	case STORAGE_ALIAS:
 	case STORAGE_BOOL:
 	case STORAGE_ERROR:
 	case STORAGE_FCONST:
 	case STORAGE_FUNCTION:
 	case STORAGE_ICONST:
 	case STORAGE_RCONST:
 	case STORAGE_STRING:
 	case STORAGE_STRUCT:
 	case STORAGE_TAGGED:
 	case STORAGE_TUPLE:
 	case STORAGE_UNION:
 	case STORAGE_VALIST:
 	case STORAGE_VOID:
 		abort(); // Invariant
 	}
 
 	return result;
 }
 
 static struct gen_value
 gen_expr_compound_with(struct gen_context *ctx,
 	const struct expression *expr,
 	struct gen_value *out)
 {
 	struct qbe_statement lend;
 	struct qbe_value bend = mklabel(ctx, &lend, ".%d");
 	struct gen_scope *scope = push_scope(ctx, expr->compound.scope);
 	scope->end = &bend;
 
 	struct gen_value gvout = gv_void;
 	if (!out) {
 		gvout = mkgtemp(ctx, expr->result, ".%d");
 	}
 	scope->out = out;
 	scope->result = gvout;
 
 	const struct expressions *exprs;
 	for (exprs = &expr->compound.exprs; exprs->next; exprs = exprs->next) {
 		gen_expr(ctx, exprs->expr);
 	}
 
 	struct gen_value last = gen_expr_with(ctx, exprs->expr, out);
 	branch_copyresult(ctx, last, gvout, out);
 	pop_scope(ctx, !exprs->expr->terminates);
 	push(&ctx->current->body, &lend);
 	return gvout;
 }
 
 static void
 gen_const_array_at(struct gen_context *ctx,
 	const struct expression *expr,
 	struct gen_value out)
 {
 	struct array_constant *aexpr = expr->constant.array;
 	struct qbe_value base = mkqval(ctx, &out);
 
 	size_t n = 0;
 	const struct type *atype = type_dealias(expr->result);
 	size_t msize = atype->array.members->size;
 	struct gen_value item = mkgtemp(ctx, atype->array.members, "item.%d");
 	for (const struct array_constant *ac = aexpr; ac; ac = ac->next) {
 		struct qbe_value offs = constl(n * msize);
 		struct qbe_value ptr = mklval(ctx, &item);
 		pushi(ctx->current, &ptr, Q_ADD, &base, &offs, NULL);
 		gen_expr_at(ctx, ac->value, item);
 		++n;
 	}
 	assert(n == atype->array.length);
 	if (!atype->array.expandable || n == 0) {
 		return;
 	}
 	assert(out.type);
 	const struct type_array arr = type_dealias(out.type)->array;
 	if (arr.length <= n) {
 		return;
 	}
 
 	// last copied element
 	struct qbe_value lsize = constl((n - 1) * msize);
 	struct qbe_value last = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 	pushi(ctx->current, &last, Q_ADD, &base, &lsize, NULL);
 	// start from the elements already copied
 	struct qbe_value nsize = constl(n * msize);
 	struct qbe_value next = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 	pushi(ctx->current, &next, Q_ADD, &base, &nsize, NULL);
 
 	struct qbe_value rtmemcpy = mkrtfunc(ctx, "rt.memcpy");
 	struct qbe_value qlen = constl((arr.length - n) * msize);
 	pushi(ctx->current, NULL, Q_CALL, &rtmemcpy, &next, &last, &qlen, NULL);
 }
 
 static void
 gen_const_string_at(struct gen_context *ctx,
 	const struct expression *expr, struct gen_value out)
 {
 	const struct expression_constant *constant = &expr->constant;
 	const char *val = constant->string.value;
 	size_t len = constant->string.len;
 
 	// TODO: Generate string data structure as global also?
 	struct qbe_value global = mkqtmp(ctx, ctx->arch.ptr, "strdata.%d");
 	global.kind = QV_GLOBAL;
 
 	struct qbe_def *def = xcalloc(1, sizeof(struct qbe_def));
 	def->name = global.name;
 	def->kind = Q_DATA;
 	def->data.align = ALIGN_UNDEFINED;
 	def->data.items.type = QD_STRING;
 	def->data.items.str = xcalloc(1, len);
 	memcpy(def->data.items.str, val, len);
 	def->data.items.sz = len;
 
 	if (len != 0) {
 		qbe_append_def(ctx->out, def);
 	} else {
 		free(def);
 		global = constl(0);
 	}
 
 	enum qbe_instr store = store_for_type(ctx, &builtin_type_size);
 	struct qbe_value strp = mkcopy(ctx, &out, ".%d");
 	struct qbe_value qlen = constl(len);
 	struct qbe_value offs = constl(builtin_type_size.size);
 	pushi(ctx->current, NULL, store, &global, &strp, NULL);
 	pushi(ctx->current, &strp, Q_ADD, &strp, &offs, NULL);
 	pushi(ctx->current, NULL, store, &qlen, &strp, NULL);
 	pushi(ctx->current, &strp, Q_ADD, &strp, &offs, NULL);
 	pushi(ctx->current, NULL, store, &qlen, &strp, NULL);
 }
 
 static void
 gen_const_struct_at(struct gen_context *ctx,
 	const struct expression *expr, struct gen_value out)
 {
 	// TODO: Merge me into constant expressions
 	struct qbe_value base = mkqval(ctx, &out);
 
 	struct gen_value ftemp = mkgtemp(ctx, &builtin_type_void, "field.%d");
 	for (const struct struct_constant *field = expr->constant._struct;
 			field; field = field->next) {
 		assert(field->value);
 
 		struct qbe_value offs = constl(field->field->offset);
 		ftemp.type = field->value->result;
 		struct qbe_value ptr = mklval(ctx, &ftemp);
 		pushi(ctx->current, &ptr, Q_ADD, &base, &offs, NULL);
 		gen_expr_at(ctx, field->value, ftemp);
 	}
 }
 
 static void
 gen_const_tagged_at(struct gen_context *ctx,
 	const struct expression *expr, struct gen_value out)
 {
 	struct qbe_value qout = mklval(ctx, &out);
 	const struct type *subtype = expr->constant.tagged.tag;
 	struct qbe_value id = constw(subtype->id);
 	enum qbe_instr store = store_for_type(ctx, &builtin_type_uint);
 	pushi(ctx->current, NULL, store, &id, &qout, NULL);
 	if (subtype->size == 0) {
 		return;
 	}
 
 	struct gen_value storage = mkgtemp(ctx, subtype, ".%d");
 	struct qbe_value qstor = mklval(ctx, &storage);
 	struct qbe_value offs = constl(expr->result->align);
 	pushi(ctx->current, &qstor, Q_ADD, &qout, &offs, NULL);
 	gen_expr_at(ctx, expr->constant.tagged.value, storage);
 }
 
 static void
 gen_const_tuple_at(struct gen_context *ctx,
 	const struct expression *expr, struct gen_value out)
 {
 	// TODO: Merge me into constant expressions
 	struct qbe_value base = mkqval(ctx, &out);
 
 	struct gen_value ftemp = mkgtemp(ctx, &builtin_type_void, "field.%d");
 	for (const struct tuple_constant *field = expr->constant.tuple; field;
 			field = field->next) {
 		assert(field->value);
 
 		struct qbe_value offs = constl(field->field->offset);
 		ftemp.type = field->value->result;
 		struct qbe_value ptr = mklval(ctx, &ftemp);
 		pushi(ctx->current, &ptr, Q_ADD, &base, &offs, NULL);
 		gen_expr_at(ctx, field->value, ftemp);
 	}
 }
 
 static void
 gen_expr_const_at(struct gen_context *ctx,
 	const struct expression *expr, struct gen_value out)
 {
 	if (!type_is_aggregate(type_dealias(expr->result))) {
 		gen_store(ctx, out, gen_expr(ctx, expr));
 		return;
 	}
 
 	switch (type_dealias(expr->result)->storage) {
 	case STORAGE_ARRAY:
 		gen_const_array_at(ctx, expr, out);
 		break;
 	case STORAGE_STRING:
 		gen_const_string_at(ctx, expr, out);
 		break;
 	case STORAGE_STRUCT:
 		gen_const_struct_at(ctx, expr, out);
 		break;
 	case STORAGE_TAGGED:
 		gen_const_tagged_at(ctx, expr, out);
 		break;
 	case STORAGE_TUPLE:
 		gen_const_tuple_at(ctx, expr, out);
 		break;
 	default:
 		abort(); // Invariant
 	}
 }
 
 static struct gen_value
 gen_expr_const(struct gen_context *ctx, const struct expression *expr)
 {
 	if (type_is_aggregate(type_dealias(expr->result))) {
 		struct gen_value out = mkgtemp(ctx, expr->result, "object.%d");
 		struct qbe_value base = mkqval(ctx, &out);
 		struct qbe_value sz = constl(expr->result->size);
 		enum qbe_instr alloc = alloc_for_align(expr->result->align);
 		pushprei(ctx->current, &base, alloc, &sz, NULL);
 		gen_expr_at(ctx, expr, out);
 		return out;
 	}
 
 	struct gen_value val = {
 		.kind = GV_CONST,
 		.type = expr->result,
 	};
 
 	// Special cases
 	switch (type_dealias(expr->result)->storage) {
 	case STORAGE_BOOL:
 		val.wval = expr->constant.bval ? 1 : 0;
 		return val;
 	case STORAGE_VOID:
 		return val;
 	case STORAGE_NULL:
 		val.lval = 0;
 		return val;
 	default:
 		// Moving right along
 		break;
 	}
 
 	if (expr->constant.object != NULL) {
 		assert(expr->constant.ival == 0);
 		val = gen_access_ident(ctx, expr->constant.object);
 		val.type = expr->result;
 		return val;
 	}
 
 	const struct qbe_type *qtype = qtype_lookup(ctx, expr->result, false);
 	switch (qtype->stype) {
 	case Q_BYTE:
 	case Q_HALF:
 	case Q_WORD:
 		val.wval = (uint32_t)expr->constant.uval;
 		return val;
 	case Q_LONG:
 		val.lval = expr->constant.uval;
 		return val;
 	case Q_SINGLE:
 		val.sval = (float)expr->constant.fval;
 		return val;
 	case Q_DOUBLE:
 		val.dval = expr->constant.fval;
 		return val;
 	case Q__VOID:
 		return val;
 	case Q__AGGREGATE:
 		assert(0); // Invariant
 	}
 
 	abort(); // Invariant
 }
 
 static struct gen_value
 gen_expr_defer(struct gen_context *ctx, const struct expression *expr)
 {
 	struct gen_defer *defer = xcalloc(1, sizeof(struct gen_defer));
 	defer->expr = expr->defer.deferred;
 	defer->next = ctx->scope->defers;
 	ctx->scope->defers = defer;
 	return gv_void;
 }
 
 static struct gen_value
 gen_expr_delete(struct gen_context *ctx, const struct expression *expr)
 {
 	struct gen_value object, start;
 	const struct expression *dexpr = expr->delete.expr;
 	if (dexpr->type == EXPR_SLICE) {
 		object = gen_expr(ctx, dexpr->slice.object);
 		if (dexpr->slice.start) {
 			start = gen_expr(ctx, dexpr->slice.start);
 		} else {
 			start.kind = GV_CONST;
 			start.type = &builtin_type_size;
 			start.lval = 0;
 		}
 	} else {
 		assert(dexpr->type == EXPR_ACCESS
 			&& dexpr->access.type == ACCESS_INDEX);
 		object = gen_expr(ctx, dexpr->access.array);
 		start = gen_expr(ctx, dexpr->access.index);
 	}
 	object = gen_autoderef(ctx, object);
 	assert(type_dealias(object.type)->storage == STORAGE_SLICE);
 
 	struct qbe_value qobj = mkqval(ctx, &object);
 	struct qbe_value qlenptr = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 	struct qbe_value qlen = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 	struct qbe_value offset = constl(builtin_type_size.size);
 	enum qbe_instr load = load_for_type(ctx, &builtin_type_size);
 	pushi(ctx->current, &qlenptr, Q_ADD, &qobj, &offset, NULL);
 	pushi(ctx->current, &qlen, load, &qlenptr, NULL);
 
 	struct qbe_value qstart = mkqval(ctx, &start);
 	struct qbe_value qend = {0};
 	if (dexpr->type == EXPR_SLICE) {
 		if (dexpr->slice.end) {
 			struct gen_value end = gen_expr(ctx, dexpr->slice.end);
 			qend = mkqval(ctx, &end);
 		} else {
 			qend = qlen;
 		}
 	} else {
 		struct qbe_value tmp = constl(1);
 		qend = mkqtmp(ctx, qstart.type, ".%d");
 		pushi(ctx->current, &qend, Q_ADD, &qstart, &tmp, NULL);
 	}
 
 	struct qbe_value start_oob = mkqtmp(ctx, &qbe_word, ".%d");
 	struct qbe_value end_oob = mkqtmp(ctx, &qbe_word, ".%d");
 	struct qbe_value startend_oob = mkqtmp(ctx, &qbe_word, ".%d");
 	struct qbe_value valid = mkqtmp(ctx, &qbe_word, ".%d");
 	pushi(ctx->current, &start_oob, Q_CULEL, &qstart, &qlen, NULL);
 	pushi(ctx->current, &end_oob, Q_CULEL, &qend, &qlen, NULL);
 	pushi(ctx->current, &valid, Q_AND, &start_oob, &end_oob, NULL);
 	pushi(ctx->current, &startend_oob, Q_CULEL, &qstart, &qend, NULL);
 	pushi(ctx->current, &valid, Q_AND, &valid, &startend_oob, NULL);
 
 	struct qbe_statement linvalid, lvalid;
 	struct qbe_value binvalid = mklabel(ctx, &linvalid, ".%d");
 	struct qbe_value bvalid = mklabel(ctx, &lvalid, ".%d");
 
 	pushi(ctx->current, NULL, Q_JNZ, &valid, &bvalid, &binvalid, NULL);
 	push(&ctx->current->body, &linvalid);
 	gen_fixed_abort(ctx, expr->loc, ABORT_OOB);
 	push(&ctx->current->body, &lvalid);
 
 	struct qbe_value data = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 	struct qbe_value startptr = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 	struct qbe_value endptr = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 	struct qbe_value mlen = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 	pushi(ctx->current, &data, load, &qobj, NULL);
 	struct qbe_value membsz =
 		constl(type_dealias(object.type)->array.members->size);
 	pushi(ctx->current, &startptr, Q_MUL, &qstart, &membsz, NULL);
 	pushi(ctx->current, &startptr, Q_ADD, &startptr, &data, NULL);
 	pushi(ctx->current, &endptr, Q_MUL, &qend, &membsz, NULL);
 	pushi(ctx->current, &endptr, Q_ADD, &endptr, &data, NULL);
 	pushi(ctx->current, &qlen, Q_SUB, &qlen, &qend, NULL);
 	pushi(ctx->current, &mlen, Q_MUL, &qlen, &membsz, NULL);
 
 	struct qbe_value rtmemmove = mkrtfunc(ctx, "rt.memmove");
 	pushi(ctx->current, NULL, Q_CALL, &rtmemmove, &startptr, &endptr, &mlen,
 		NULL);
 
 	pushi(ctx->current, &qlen, Q_ADD, &qlen, &qstart, NULL);
 	enum qbe_instr store = store_for_type(ctx, &builtin_type_size);
 	pushi(ctx->current, NULL, store, &qlen, &qlenptr, NULL);
 
 	if (!expr->delete.is_static) {
 		struct qbe_value rtunensure = mkrtfunc(ctx, "rt.unensure");
 		qobj = mklval(ctx, &object);
 		pushi(ctx->current, NULL, Q_CALL, &rtunensure, &qobj, &membsz,
 			NULL);
 	}
 
 	return gv_void;
 }
 
 static struct gen_value
 gen_expr_for(struct gen_context *ctx, const struct expression *expr)
 {
 	struct qbe_statement lloop, lbody, lafter, lend;
 	struct qbe_value bloop = mklabel(ctx, &lloop, "loop.%d");
 	struct qbe_value bbody = mklabel(ctx, &lbody, "body.%d");
 	struct qbe_value bend = mklabel(ctx, &lend, ".%d");
 	struct qbe_value bafter = mklabel(ctx, &lafter, "after.%d");
 
 	if (expr->_for.bindings) {
 		gen_expr_binding(ctx, expr->_for.bindings);
 	}
 
 	push_scope(ctx, expr->_for.scope);
 	ctx->scope->after = &bafter;
 	ctx->scope->end = &bend;
 
 	push(&ctx->current->body, &lloop);
 	struct gen_value cond = gen_expr(ctx, expr->_for.cond);
 	struct qbe_value qcond = mkqval(ctx, &cond);
 	pushi(ctx->current, NULL, Q_JNZ, &qcond, &bbody, &bend, NULL);
 
 	push(&ctx->current->body, &lbody);
 	gen_expr(ctx, expr->_for.body);
 
 	push(&ctx->current->body, &lafter);
 	if (expr->_for.afterthought) {
 		gen_expr(ctx, expr->_for.afterthought);
 	}
 
 	pop_scope(ctx, true);
 
 	pushi(ctx->current, NULL, Q_JMP, &bloop, NULL);
 
 	push(&ctx->current->body, &lend);
 	return gv_void;
 }
 
 static struct gen_value
 gen_expr_free(struct gen_context *ctx, const struct expression *expr)
 {
 	const struct type *type = type_dealias(expr->free.expr->result);
 	struct qbe_value rtfunc = mkrtfunc(ctx, "rt.free");
 	struct gen_value val = gen_expr(ctx, expr->free.expr);
 	struct qbe_value qval = mkqval(ctx, &val);
 	if (type->storage == STORAGE_SLICE || type->storage == STORAGE_STRING) {
 		struct qbe_value lval = mklval(ctx, &val);
 		qval = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 		pushi(ctx->current, &qval, Q_LOADL, &lval, NULL);
 	}
 	pushi(ctx->current, NULL, Q_CALL, &rtfunc, &qval, NULL);
 	return gv_void;
 }
 
 static struct gen_value
 gen_expr_if_with(struct gen_context *ctx,
 	const struct expression *expr,
 	struct gen_value *out)
 {
 	struct gen_value gvout = gv_void;
 	if (!out) {
 		gvout = mkgtemp(ctx, expr->result, ".%d");
 	}
 
 	struct qbe_statement ltrue, lfalse, lend;
 	struct qbe_value btrue = mklabel(ctx, &ltrue, "true.%d");
 	struct qbe_value bfalse = mklabel(ctx, &lfalse, "false.%d");
 	struct qbe_value bend = mklabel(ctx, &lend, ".%d");
 	struct gen_value cond = gen_expr(ctx, expr->_if.cond);
 	struct qbe_value qcond = mkqval(ctx, &cond);
 	qcond = extend(ctx, qcond, &builtin_type_bool);
 	pushi(ctx->current, NULL, Q_JNZ, &qcond, &btrue, &bfalse, NULL);
 
 	push(&ctx->current->body, &ltrue);
 	struct gen_value vtrue = gen_expr_with(ctx, expr->_if.true_branch, out);
 	branch_copyresult(ctx, vtrue, gvout, out);
 	if (!expr->_if.true_branch->terminates) {
 		pushi(ctx->current, NULL, Q_JMP, &bend, NULL);
 	}
 
 	push(&ctx->current->body, &lfalse);
 	if (expr->_if.false_branch) {
 		struct gen_value vfalse = gen_expr_with(ctx,
 				expr->_if.false_branch, out);
 		branch_copyresult(ctx, vfalse, gvout, out);
 	}
 
 	push(&ctx->current->body, &lend);
 	return gvout;
 }
 
 static struct gen_value
 gen_expr_insert(struct gen_context *ctx, const struct expression *expr)
 {
 	// XXX: A lot of this code is identical to the corresponding append
 	// code, maybe we can/should deduplicate it
 	assert(expr->append.length == NULL);
 	const struct expression *objexpr = expr->append.object;
 	assert(objexpr->type == EXPR_ACCESS
 			&& objexpr->access.type == ACCESS_INDEX);
 	const struct expression *arexpr = objexpr->access.array;
 	struct gen_value slice = gen_expr(ctx, arexpr);
 	slice = gen_autoderef(ctx, slice);
 	struct qbe_value qslice = mkqval(ctx, &slice);
 	struct gen_value index = gen_expr(ctx, objexpr->access.index);
 	struct qbe_value qindex = mkqval(ctx, &index);
 
 	struct qbe_value lenptr = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 	struct qbe_value prevlen = mkqtmp(ctx, ctx->arch.sz, ".%d");
 	struct qbe_value offs = constl(builtin_type_size.size);
 	pushi(ctx->current, &lenptr, Q_ADD, &qslice, &offs, NULL);
 	enum qbe_instr load = load_for_type(ctx, &builtin_type_size);
 	pushi(ctx->current, &prevlen, load, &lenptr, NULL);
 
 	struct qbe_value appendlen = constl(1);
 	const struct type *valtype = type_dealias(expr->append.value->result);
 
 	struct gen_value value;
 	struct qbe_value qvalue;
 	if (!expr->append.is_multi || valtype->storage != STORAGE_ARRAY) {
 		// We use gen_expr_at for the array case to avoid a copy
 		value = gen_expr(ctx, expr->append.value);
 		qvalue = mkqval(ctx, &value);
 	}
 
 	if (expr->append.is_multi) {
 		if (valtype->storage == STORAGE_ARRAY) {
 			assert(valtype->array.length != SIZE_UNDEFINED);
 			appendlen = constl(valtype->array.length);
 		} else {
 			appendlen = mkqtmp(ctx, ctx->arch.sz, ".%d");
 			struct qbe_value ptr = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 			offs = constl(builtin_type_size.size);
 			pushi(ctx->current, &ptr, Q_ADD, &qvalue, &offs, NULL);
 			pushi(ctx->current, &appendlen, load, &ptr, NULL);
 		}
 	}
 
 	struct qbe_value newlen = mkqtmp(ctx, ctx->arch.sz, ".%d");
 	pushi(ctx->current, &newlen, Q_ADD, &prevlen, &appendlen, NULL);
 	enum qbe_instr store = store_for_type(ctx, &builtin_type_size);
 	pushi(ctx->current, NULL, store, &newlen, &lenptr, NULL);
 
 	struct qbe_value ptr = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 	const struct type *mtype = type_dealias(slice.type)->array.members;
 	struct qbe_value membsz = constl(mtype->size);
 	if (!expr->append.is_static) {
 		struct qbe_value rtfunc = mkrtfunc(ctx, "rt.ensure");
 		struct qbe_value lval = mklval(ctx, &slice);
 		pushi(ctx->current, NULL, Q_CALL, &rtfunc, &lval, &membsz, NULL);
 	} else {
 		offs = constl(builtin_type_size.size * 2);
 		pushi(ctx->current, &ptr, Q_ADD, &qslice, &offs, NULL);
 		struct qbe_value cap = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 		pushi(ctx->current, &cap, load, &ptr, NULL);
 
 		struct qbe_statement lvalid, linvalid;
 		struct qbe_value bvalid = mklabel(ctx, &lvalid, ".%d");
 		struct qbe_value binvalid = mklabel(ctx, &linvalid, ".%d");
 		struct qbe_value valid = mkqtmp(ctx, &qbe_word, ".%d");
 		pushi(ctx->current, &valid, Q_CULEL, &newlen, &cap, NULL);
 		pushi(ctx->current, NULL, Q_JNZ, &valid, &bvalid, &binvalid, NULL);
 
 		push(&ctx->current->body, &linvalid);
 		gen_fixed_abort(ctx, expr->loc, ABORT_OOB);
 		push(&ctx->current->body, &lvalid);
 	}
 
 	struct qbe_value base = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 	pushi(ctx->current, &base, load, &qslice, NULL);
 
 	pushi(ctx->current, &ptr, Q_MUL, &qindex, &membsz, NULL);
 	pushi(ctx->current, &ptr, Q_ADD, &base, &ptr, NULL);
 
 	struct qbe_value nbyte = mkqtmp(ctx, ctx->arch.sz, ".%d");
 	struct qbe_value dest = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 	struct qbe_value ncopy = mkqtmp(ctx, ctx->arch.sz, ".%d");
 	pushi(ctx->current, &nbyte, Q_MUL, &appendlen, &membsz, NULL);
 	pushi(ctx->current, &ncopy, Q_SUB, &prevlen, &qindex, NULL);
 	pushi(ctx->current, &ncopy, Q_MUL, &ncopy, &membsz, NULL);
 	pushi(ctx->current, &dest, Q_ADD, &ptr, &nbyte, NULL);
 
 	struct qbe_value rtfunc = mkrtfunc(ctx, "rt.memmove");
 	pushi(ctx->current, NULL, Q_CALL, &rtfunc, &dest, &ptr, &ncopy, NULL);
 
 	struct gen_value item = {
 		.kind = GV_TEMP,
 		.type = mtype,
 		.name = ptr.name,
 	};
 	if (expr->append.is_multi && valtype->storage == STORAGE_ARRAY) {
 		item.type = valtype;
 		gen_expr_at(ctx, expr->append.value, item);
 	} else if (expr->append.is_multi && valtype->storage == STORAGE_SLICE) {
 		struct qbe_value qsrc = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 		struct qbe_value rtfunc = mkrtfunc(ctx, "rt.memmove");
 		pushi(ctx->current, &qsrc, load, &qvalue, NULL);
 		pushi(ctx->current, NULL, Q_CALL, &rtfunc, &ptr, &qsrc, &nbyte, NULL);
 	} else {
 		gen_store(ctx, item, value);
 	}
 
 	return gv_void;
 }
 
 enum match_compat {
 	// The case type is a member of the match object type and can be used
 	// directly from the match object's tagged union storage area.
 	COMPAT_SUBTYPE,
 	// The case type is a tagged union which is a subset of the object type,
 	// and alignment-compatible. In this case we can use the match object
 	// directly.
 	COMPAT_ALIGNED,
 	// The case type is a tagged union which is a subset of the object type,
 	// but with a different alignment. In this case we must convert the
 	// match object before using it.
 	COMPAT_MISALIGNED,
 };
 
 static struct qbe_value
 nested_tagged_offset(const struct type *tu, const struct type *target)
 {
 	// This function calculates the offset of a member in a nested tagged union
 	//
 	// type foo = (int | void);
 	// type bar = (size | foo);
 	//
 	// Offset of the foo field from the start of bar is 8 and offset of int
 	// inside foo is 4, so the offset of the int from the start of bar is 12
 	const struct type *test = tu;
 	struct qbe_value offset = constl(tu->align);
 	do {
 		test = tagged_select_subtype(tu, target, false);
 		if (!test) {
 			break;
 		}
 		if (test->id != target->id && type_dealias(test)->id != target->id) {
 			offset.lval += test->align;
 		}
 		tu = test;
 	} while (test->id != target->id && type_dealias(test)->id != target->id);
 	return offset;
 }
 
 static struct gen_value
 gen_nested_match_tests(struct gen_context *ctx, struct gen_value object,
 	struct qbe_value bmatch, struct qbe_value bnext,
 	struct qbe_value tag, const struct type *type)
 {
 	// This function handles the case where we're matching against a type
 	// which is a member of the tagged union, or an inner tagged union.
 	//
 	// type foo = (int | void);
 	// type bar = (size | foo);
 	//
 	// let x: bar = 10i;
 	// match (x) {
 	// case let z: size => ...
 	// case let i: int => ...
 	// case	void => ...
 	// };
 	//
 	// In the first case, we can simply test the object's tag. In the second
 	// case, we have to test if the selected tag is 'foo', then check the
 	// tag of the foo object for int.
 	struct qbe_value *subtag = &tag;
 	struct qbe_value subval = mkcopy(ctx, &object, "subval.%d");
 	struct gen_value match = mkgtemp(ctx, &builtin_type_bool, ".%d");
 	struct qbe_value qmatch = mkqval(ctx, &match);
 	struct qbe_value temp = mkqtmp(ctx, &qbe_word, ".%d");
 	const struct type *subtype = object.type;
 	const struct type *test = type;
 	do {
 		struct qbe_statement lsubtype;
 		struct qbe_value bsubtype = mklabel(ctx, &lsubtype, "subtype.%d");
 
 		if (type_dealias(subtype)->storage != STORAGE_TAGGED) {
 			break;
 		}
 		test = tagged_select_subtype(subtype, type, false);
 		if (!test) {
 			break;
 		}
 
 		struct qbe_value id = constw(test->id);
 		pushi(ctx->current, &qmatch, Q_CEQW, subtag, &id, NULL);
 		pushi(ctx->current, NULL, Q_JNZ, &qmatch, &bsubtype, &bnext, NULL);
 		push(&ctx->current->body, &lsubtype);
 
 		if (test->id != type->id && type_dealias(test)->id != type->id) {
 			struct qbe_value offs = constl(subtype->align);
 			pushi(ctx->current, &subval, Q_ADD, &subval, &offs, NULL);
 			pushi(ctx->current, &temp, Q_LOADUW, &subval, NULL);
 			subtag = &temp;
 		}
 
 		subtype = test;
 	} while (test->id != type->id && type_dealias(test)->id != type->id);
 
 	pushi(ctx->current, NULL, Q_JMP, &bmatch, NULL);
 	return match;
 }
 
 static struct gen_value
 gen_subset_match_tests(struct gen_context *ctx,
 	struct qbe_value bmatch, struct qbe_value bnext,
 	struct qbe_value tag, const struct type *type)
 {
 	// In this case, we're testing a case which is itself a tagged union,
 	// and is a subset of the match object.
 	//
 	// type foo = (size | int | void);
 	//
 	// let x: foo = 10i;
 	// match (x) {
 	// case let n: (size | int) => ...
 	// case void => ...
 	// };
 	//
 	// In this situation, we test the match object's tag against each type
 	// ID of the case type.
 	struct gen_value match = mkgtemp(ctx, &builtin_type_bool, ".%d");
 	for (const struct type_tagged_union *tu = &type->tagged; tu; tu = tu->next) {
 		struct qbe_statement lnexttag;
 		struct qbe_value bnexttag = mklabel(ctx, &lnexttag, ".%d");
 		struct qbe_value id = constl(tu->type->id);
 		struct qbe_value qmatch = mkqval(ctx, &match);
 		pushi(ctx->current, &qmatch, Q_CEQW, &tag, &id, NULL);
 		pushi(ctx->current, NULL, Q_JNZ, &qmatch, &bmatch, &bnexttag, NULL);
 		push(&ctx->current->body, &lnexttag);
 	}
 	pushi(ctx->current, NULL, Q_JMP, &bnext, NULL);
 	return match;
 }
 
 static struct gen_value
 gen_match_with_tagged(struct gen_context *ctx,
 	const struct expression *expr,
 	struct gen_value *out)
 {
 	struct gen_value gvout = gv_void;
 	if (!out) {
 		gvout = mkgtemp(ctx, expr->result, ".%d");
 	}
 
 	const struct type *objtype = expr->match.value->result;
 	struct gen_value object = gen_expr(ctx, expr->match.value);
 	struct qbe_value qobject = mkqval(ctx, &object);
 	struct qbe_value tag = mkqtmp(ctx, ctx->arch.sz, "tag.%d");
 	enum qbe_instr load = load_for_type(ctx, &builtin_type_uint);
 	pushi(ctx->current, &tag, load, &qobject, NULL);
 
 	struct qbe_statement lout;
 	struct qbe_value bout = mklabel(ctx, &lout, ".%d");
 
 	struct gen_value bval;
 	const struct match_case *_default = NULL;
 	for (const struct match_case *_case = expr->match.cases;
 			_case; _case = _case->next) {
 		if (!_case->type) {
 			_default = _case;
 			continue;
 		}
 
 		struct qbe_statement lmatch, lnext;
 		struct qbe_value bmatch = mklabel(ctx, &lmatch, "matches.%d");
 		struct qbe_value bnext = mklabel(ctx, &lnext, "next.%d");
 		const struct type *subtype =
 			tagged_select_subtype(objtype, _case->type, false);
 		enum match_compat compat = COMPAT_SUBTYPE;
 		if (subtype) {
 			gen_nested_match_tests(ctx, object,
 				bmatch, bnext, tag, _case->type);
 		} else {
 			assert(type_dealias(_case->type)->storage == STORAGE_TAGGED);
 			assert(tagged_subset_compat(objtype, _case->type));
 			if (tagged_align_compat(objtype, _case->type)) {
 				compat = COMPAT_ALIGNED;
 			} else {
 				compat = COMPAT_MISALIGNED;
 			}
 			const struct type *casetype = type_dealias(_case->type);
 			gen_subset_match_tests(ctx, bmatch, bnext, tag, casetype);
 		}
 
 		push(&ctx->current->body, &lmatch);
 
 		if (!_case->object) {
 			goto next;
 		}
 
 		struct gen_binding *gb = xcalloc(1, sizeof(struct gen_binding));
 		gb->value.kind = GV_TEMP;
 		gb->value.type = _case->type;
 		gb->value.name = gen_name(&ctx->id, "binding.%d");
 		gb->object = _case->object;
 		gb->next = ctx->bindings;
 		ctx->bindings = gb;
 
 		struct qbe_value qv = mklval(ctx, &gb->value);
 		enum qbe_instr alloc = alloc_for_align(_case->type->align);
 		struct qbe_value sz = constl(_case->type->size);
 		pushprei(ctx->current, &qv, alloc, &sz, NULL);
 
 		struct qbe_value ptr = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 		struct gen_value src = {
 			.kind = GV_TEMP,
 			.type = _case->type,
 			.name = ptr.name,
 		};
 		struct gen_value load;
 		struct qbe_value offset;
 		switch (compat) {
 		case COMPAT_SUBTYPE:
 			offset = nested_tagged_offset(object.type, _case->type);
 			pushi(ctx->current, &ptr, Q_ADD, &qobject, &offset, NULL);
 			load = gen_load(ctx, src);
 			gen_store(ctx, gb->value, load);
 			break;
 		case COMPAT_ALIGNED:
 			pushi(ctx->current, &ptr, Q_COPY, &qobject, NULL);
 			load = gen_load(ctx, src);
 			gen_store(ctx, gb->value, load);
 			break;
 		case COMPAT_MISALIGNED:
 			;
 			struct expression value = {
 				.type = EXPR_GEN_VALUE,
 				.result = objtype,
 				.user = &object,
 			};
 			struct expression cast = {
 				.type = EXPR_CAST,
 				.result = _case->type,
 				.cast = {
 					.kind = C_CAST,
 					.secondary = _case->type,
 					.value = &value,
 				},
 			};
 			gen_expr_at(ctx, &cast, gb->value);
 			break;
 		}
 
 next:
 		bval = gen_expr_with(ctx, _case->value, out);
 		branch_copyresult(ctx, bval, gvout, out);
 		if (!_case->value->terminates) {
 			pushi(ctx->current, NULL, Q_JMP, &bout, NULL);
 		}
 		push(&ctx->current->body, &lnext);
 	}
 
 	if (_default) {
 		bval = gen_expr_with(ctx, _default->value, out);
 		branch_copyresult(ctx, bval, gvout, out);
 	} else {
 		struct qbe_statement labort;
 		mklabel(ctx, &labort, ".%d");
 		push(&ctx->current->body, &labort);
 		gen_fixed_abort(ctx, expr->loc, ABORT_UNREACHABLE);
 	}
 
 	push(&ctx->current->body, &lout);
 	return gvout;
 }
 
 static struct gen_value
 gen_match_with_nullable(struct gen_context *ctx,
 	const struct expression *expr,
 	struct gen_value *out)
 {
 	struct gen_value gvout = gv_void;
 	if (!out) {
 		gvout = mkgtemp(ctx, expr->result, ".%d");
 	}
 
 	struct qbe_statement lout;
 	struct qbe_value bout = mklabel(ctx, &lout, ".%d");
 	struct gen_value object = gen_expr(ctx, expr->match.value);
 	struct qbe_value qobject = mkqval(ctx, &object);
 	struct qbe_value zero = constl(0);
 
 	struct gen_value bval;
 	const struct match_case *_default = NULL;
 	for (const struct match_case *_case = expr->match.cases;
 			_case; _case = _case->next) {
 		if (!_case->type) {
 			_default = _case;
 			continue;
 		}
 
 		struct qbe_statement lmatch, lnext;
 		struct qbe_value cmpres = mkqtmp(ctx, &qbe_word, ".%d");
 		struct qbe_value bmatch = mklabel(ctx, &lmatch, "matches.%d");
 		struct qbe_value bnext = mklabel(ctx, &lnext, "next.%d");
 
 		enum qbe_instr compare;
 		if (_case->type->storage == STORAGE_NULL) {
 			compare = Q_CEQL;
 		} else {
 			compare = Q_CNEL;
 		}
 		pushi(ctx->current, &cmpres, compare, &qobject, &zero, NULL);
 		pushi(ctx->current, NULL, Q_JNZ, &cmpres, &bmatch, &bnext, NULL);
 
 		push(&ctx->current->body, &lmatch);
 
 		if (!_case->object) {
 			goto next;
 		}
 
 		struct gen_binding *gb = xcalloc(1, sizeof(struct gen_binding));
 		gb->value = mkgtemp(ctx, _case->type, "binding.%d");
 		gb->object = _case->object;
 		gb->next = ctx->bindings;
 		ctx->bindings = gb;
 
 		enum qbe_instr store = store_for_type(ctx, _case->type);
 		enum qbe_instr alloc = alloc_for_align(_case->type->align);
 		struct qbe_value qv = mkqval(ctx, &gb->value);
 		struct qbe_value sz = constl(_case->type->size);
 		pushprei(ctx->current, &qv, alloc, &sz, NULL);
 		pushi(ctx->current, NULL, store, &qobject, &qv, NULL);
 
 next:
 		bval = gen_expr_with(ctx, _case->value, out);
 		branch_copyresult(ctx, bval, gvout, out);
 		if (!_case->value->terminates) {
 			pushi(ctx->current, NULL, Q_JMP, &bout, NULL);
 		}
 		push(&ctx->current->body, &lnext);
 	}
 
 	if (_default) {
 		bval = gen_expr_with(ctx, _default->value, out);
 		branch_copyresult(ctx, bval, gvout, out);
 		if (!_default->value->terminates) {
 			pushi(ctx->current, NULL, Q_JMP, &bout, NULL);
 		}
 	}
 
 	struct qbe_statement labort;
 	mklabel(ctx, &labort, ".%d");
 	push(&ctx->current->body, &labort);
 	gen_fixed_abort(ctx, expr->loc, ABORT_UNREACHABLE);
 
 	push(&ctx->current->body, &lout);
 	return gvout;
 }
 
 static struct gen_value
 gen_expr_match_with(struct gen_context *ctx,
 	const struct expression *expr,
 	struct gen_value *out)
 {
 	const struct type *objtype = expr->match.value->result;
 	switch (type_dealias(objtype)->storage) {
 	case STORAGE_POINTER:
 		return gen_match_with_nullable(ctx, expr, out);
 	case STORAGE_TAGGED:
 		return gen_match_with_tagged(ctx, expr, out);
 	default: abort(); // Invariant
 	}
 }
 
 static struct gen_value
 gen_expr_measure(struct gen_context *ctx, const struct expression *expr)
 {
 	size_t len;
 	struct gen_value gv, temp;
 	const struct type *type;
 	const struct expression *value = expr->measure.value;
 	switch (expr->measure.op) {
 	case M_LEN:
 		type = type_dealias(type_dereference(value->result));
 		switch (type->storage) {
 		case STORAGE_ARRAY:
 			len = type->array.length;
 			assert(len != SIZE_UNDEFINED);
 			return (struct gen_value){
 				.kind = GV_CONST,
 				.type = &builtin_type_size,
 				.lval = len,
 			};
 		case STORAGE_SLICE:
 		case STORAGE_STRING:
 			gv = gen_expr(ctx, value);
 			gv = gen_autoderef(ctx, gv);
 			temp = mkgtemp(ctx, &builtin_type_size, ".%d");
 			struct qbe_value qv = mkqval(ctx, &gv),
 				qtemp = mkqval(ctx, &temp),
 				offs = constl(builtin_type_size.size);
 			enum qbe_instr load = load_for_type(ctx,
 				&builtin_type_size);
 			pushi(ctx->current, &qtemp, Q_ADD, &qv, &offs, NULL);
 			pushi(ctx->current, &qtemp, load, &qtemp, NULL);
 			return temp;
 		default:
 			abort(); // Invariant
 		}
 		break;
 	case M_ALIGN:
 		return (struct gen_value){
 			.kind = GV_CONST,
 			.type = &builtin_type_size,
 			.lval = expr->measure.dimensions.align,
 		};
 	case M_SIZE:
 		return (struct gen_value){
 			.kind = GV_CONST,
 			.type = &builtin_type_size,
 			.lval = expr->measure.dimensions.size,
 		};
 	case M_OFFSET:
 		if (expr->measure.value->access.type == ACCESS_FIELD) {
 			return (struct gen_value){
 				.kind = GV_CONST,
 				.type = &builtin_type_size,
 				.lval = expr->measure.value->access.field->offset,
 			};
 		} else {
 			assert(expr->measure.value->access.type == ACCESS_TUPLE);
 			return (struct gen_value){
 				.kind = GV_CONST,
 				.type = &builtin_type_size,
 				.lval = expr->measure.value->access.tvalue->offset,
 			};
 		}
 	}
 	abort(); // Invariant
 }
 
 static struct gen_value
 gen_expr_return(struct gen_context *ctx, const struct expression *expr)
 {
 	struct gen_value ret = gen_expr(ctx, expr->_return.value);
 	for (struct gen_scope *scope = ctx->scope; scope; scope = scope->parent) {
 		gen_defers(ctx, scope);
 	}
 	if (type_dealias(ret.type)->storage == STORAGE_VOID) {
 		pushi(ctx->current, NULL, Q_RET, NULL);
 	} else {
 		struct qbe_value qret = mkqval(ctx, &ret);
 		pushi(ctx->current, NULL, Q_RET, &qret, NULL);
 	}
 	return gv_void;
 }
 
 static void
 gen_expr_struct_at(struct gen_context *ctx,
 	const struct expression *expr,
 	struct gen_value out)
 {
 	// TODO: Merge me into constant expressions
 	struct qbe_value base = mkqval(ctx, &out);
 
 	if (expr->_struct.autofill) {
 		struct qbe_value rtfunc = mkrtfunc(ctx, "rt.memset");
 		struct qbe_value size =
 			constl(expr->result->size), zero = constl(0);
 		struct qbe_value base = mklval(ctx, &out);
 		pushi(ctx->current, NULL, Q_CALL, &rtfunc,
 			&base, &zero, &size, NULL);
 	}
 
 	struct gen_value ftemp = mkgtemp(ctx, &builtin_type_void, "field.%d");
 	for (const struct expr_struct_field *field = expr->_struct.fields;
 			field; field = field->next) {
 		if (!field->value) {
 			assert(expr->_struct.autofill);
 			continue;
 		}
 
 		struct qbe_value offs = constl(field->field->offset);
 		ftemp.type = field->value->result;
 		struct qbe_value ptr = mklval(ctx, &ftemp);
 		pushi(ctx->current, &ptr, Q_ADD, &base, &offs, NULL);
 		gen_expr_at(ctx, field->value, ftemp);
 	}
 }
 
 static struct gen_value
 gen_expr_switch_with(struct gen_context *ctx,
 	const struct expression *expr,
 	struct gen_value *out)
 {
 	struct gen_value gvout = gv_void;
 	if (!out) {
 		gvout = mkgtemp(ctx, expr->result, ".%d");
 	}
 
 	struct qbe_statement lout;
 	struct qbe_value bout = mklabel(ctx, &lout, ".%d");
 	struct gen_value value = gen_expr(ctx, expr->_switch.value);
 
 	struct gen_value bval;
 	const struct switch_case *_default = NULL;
 	for (const struct switch_case *_case = expr->_switch.cases;
 			_case; _case = _case->next) {
 		if (!_case->options) {
 			_default = _case;
 			continue;
 		}
 
 		struct qbe_statement lmatch, lnextcase;
 		struct qbe_value bmatch = mklabel(ctx, &lmatch, "matches.%d");
 		struct qbe_value bnextcase = mklabel(ctx, &lnextcase, "next.%d");
 
 		for (struct case_option *opt = _case->options;
 				opt; opt = opt->next) {
 			struct qbe_statement lnextopt;
 			struct qbe_value bnextopt = mklabel(ctx, &lnextopt, ".%d");
 			struct gen_value test = gen_expr_const(ctx, opt->value);
 			struct expression lvalue = {
 				.type = EXPR_GEN_VALUE,
 				.result = value.type,
 				.user = &value,
 			}, rvalue = {
 				.type = EXPR_GEN_VALUE,
 				.result = test.type,
 				.user = &test,
 			}, compare = {
 				.type = EXPR_BINARITHM,
 				.result = &builtin_type_bool,
 				.binarithm = {
 					.op = BIN_LEQUAL,
 					.lvalue = &lvalue,
 					.rvalue = &rvalue,
 				},
 			};
 			struct gen_value match = gen_expr(ctx, &compare);
 			struct qbe_value cond = mkqval(ctx, &match);
 			pushi(ctx->current, NULL, Q_JNZ,
 				&cond, &bmatch, &bnextopt, NULL);
 			push(&ctx->current->body, &lnextopt);
 		}
 
 		pushi(ctx->current, NULL, Q_JMP, &bnextcase, NULL);
 		push(&ctx->current->body, &lmatch);
 		bval = gen_expr_with(ctx, _case->value, out);
 		branch_copyresult(ctx, bval, gvout, out);
 		if (!_case->value->terminates) {
 			pushi(ctx->current, NULL, Q_JMP, &bout, NULL);
 		}
 		push(&ctx->current->body, &lnextcase);
 	}
 
 	if (_default) {
 		bval = gen_expr_with(ctx, _default->value, out);
 		branch_copyresult(ctx, bval, gvout, out);
 		if (!_default->value->terminates) {
 			pushi(ctx->current, NULL, Q_JMP, &bout, NULL);
 		}
 	}
 
 	struct qbe_statement labort;
 	mklabel(ctx, &labort, ".%d");
 	push(&ctx->current->body, &labort);
 	gen_fixed_abort(ctx, expr->loc, ABORT_UNREACHABLE);
 
 	push(&ctx->current->body, &lout);
 	return gvout;
 }
 
 static void
 gen_expr_slice_at(struct gen_context *ctx,
 	const struct expression *expr,
 	struct gen_value out)
 {
 	struct gen_value object = gen_expr(ctx, expr->slice.object);
 	object = gen_autoderef(ctx, object);
 	const struct type *srctype = type_dealias(object.type);
 
 	bool check_bounds = !expr->slice.bounds_checked;
 	struct gen_value length;
 	struct qbe_value qlength;
 	struct qbe_value qbase;
 	struct qbe_value qobject = mkqval(ctx, &object);
 	struct qbe_value offset = constl(builtin_type_size.size);
 	struct qbe_value qptr = mkqtmp(ctx, ctx->arch.ptr, ".%d");
 	switch (srctype->storage) {
 	case STORAGE_ARRAY:
 		if (srctype->array.length != SIZE_UNDEFINED) {
 			length = (struct gen_value){
 				.kind = GV_CONST,
 				.type = &builtin_type_size,
 				.lval = srctype->array.length,
 			};
 			qlength = mkqval(ctx, &length);
 		} else {
 			assert(expr->slice.end);
 			check_bounds = false;
 		}
 		qbase = mkqval(ctx, &object);
 		break;
 	case STORAGE_SLICE:
 		qbase = mkqtmp(ctx, ctx->arch.sz, "base.%d");
 		enum qbe_instr load = load_for_type(ctx, &builtin_type_size);
 		pushi(ctx->current, &qbase, load, &qobject, NULL);
 		length = mkgtemp(ctx, &builtin_type_size, "len.%d");
 		qlength = mkqval(ctx, &length);
 		pushi(ctx->current, &qptr, Q_ADD, &qobject, &offset, NULL);
 		pushi(ctx->current, &qlength, load, &qptr, NULL);
 		break;
 	default: abort(); // Invariant
 	}
 
 	struct gen_value start;
 	if (expr->slice.start) {
 		start = gen_expr(ctx, expr->slice.start);
 	} else {
 		start = (struct gen_value){
 			.kind = GV_CONST,
 			.type = &builtin_type_size,
 			.lval = 0,
 		};
 	}
 
 	struct gen_value end;
 	if (expr->slice.end) {
 		end = gen_expr(ctx, expr->slice.end);
 	} else {
 		end = length;
 	}
 
 	struct qbe_value qstart = mkqval(ctx, &start);
 	struct qbe_value qend = mkqval(ctx, &end);
 
 	if (check_bounds) {
 		struct qbe_value start_oob = mkqtmp(ctx, &qbe_word, ".%d");
 		struct qbe_value end_oob = mkqtmp(ctx, &qbe_word, ".%d");
 		struct qbe_value startend_oob = mkqtmp(ctx, &qbe_word, ".%d");
 		struct qbe_value valid = mkqtmp(ctx, &qbe_word, ".%d");
 		pushi(ctx->current, &start_oob, Q_CULEL, &qstart, &qlength, NULL);
 		pushi(ctx->current, &end_oob, Q_CULEL, &qend, &qlength, NULL);
 		pushi(ctx->current, &valid, Q_AND, &start_oob, &end_oob, NULL);
 		pushi(ctx->current, &startend_oob, Q_CULEL, &qstart, &qend, NULL);
 		pushi(ctx->current, &valid, Q_AND, &valid, &startend_oob, NULL);
 
 		struct qbe_statement linvalid, lvalid;
 		struct qbe_value binvalid = mklabel(ctx, &linvalid, ".%d");
 		struct qbe_value bvalid = mklabel(ctx, &lvalid, ".%d");
 
 		pushi(ctx->current, NULL, Q_JNZ, &valid, &bvalid, &binvalid, NULL);
 		push(&ctx->current->body, &linvalid);
 		gen_fixed_abort(ctx, expr->loc, ABORT_OOB);
 		push(&ctx->current->body, &lvalid);
 	}
 
 	struct qbe_value isz = constl(srctype->array.members->size);
 
 	struct qbe_value qout = mkqval(ctx, &out);
 	struct qbe_value data = mkqtmp(ctx, ctx->arch.ptr, "data.%d");
 	pushi(ctx->current, &data, Q_MUL, &qstart, &isz, NULL);
 	pushi(ctx->current, &data, Q_ADD, &qbase, &data, NULL);
 
 	struct qbe_value newlen = mkqtmp(ctx, ctx->arch.sz, "newlen.%d");
 	pushi(ctx->current, &newlen, Q_SUB, &qend, &qstart, NULL);
 	struct qbe_value newcap = mkqtmp(ctx, ctx->arch.sz, "newcap.%d");
 	if (check_bounds) {
 		pushi(ctx->current, &newcap, Q_SUB, &qlength, &qstart, NULL);
 	} else {
 		pushi(ctx->current, &newcap, Q_COPY, &newlen, NULL);
 	}
 
 	enum qbe_instr store = store_for_type(ctx, &builtin_type_size);
 	pushi(ctx->current, NULL, store, &data, &qout, NULL);
 	pushi(ctx->current, &qptr, Q_ADD, &qout, &offset, NULL);
 	pushi(ctx->current, NULL, store, &newlen, &qptr, NULL);
 	offset = constl(builtin_type_size.size * 2);
 	pushi(ctx->current, &qptr, Q_ADD, &qout, &offset, NULL);
 	pushi(ctx->current, NULL, store, &newcap, &qptr, NULL);
 }
 
 static void
 gen_expr_tuple_at(struct gen_context *ctx,
 	const struct expression *expr,
 	struct gen_value out)
 {
 	// TODO: Merge me into constant expressions
 	struct qbe_value base = mkqval(ctx, &out);
 
 	const struct type *type = type_dealias(expr->result);
 	struct gen_value vtemp = mkgtemp(ctx, &builtin_type_void, "value.%d");
 	const struct expression_tuple *value = &expr->tuple;
 	for (const struct type_tuple *tuple = &type->tuple;
 			tuple; tuple = tuple->next) {
 		struct qbe_value offs = constl(tuple->offset);
 		vtemp.type = value->value->result;
 		struct qbe_value ptr = mklval(ctx, &vtemp);
 		pushi(ctx->current, &ptr, Q_ADD, &base, &offs, NULL);
 		gen_expr_at(ctx, value->value, vtemp);
 		value = value->next;
 	}
 }
 
 static struct gen_value
 gen_expr_unarithm(struct gen_context *ctx,
 	const struct expression *expr)
 {
 	struct gen_value val, temp;
 	struct qbe_value qval, qtmp;
 	const struct expression *operand = expr->unarithm.operand;
 	switch (expr->unarithm.op) {
 	case UN_ADDRESS:
 		if (operand->type == EXPR_ACCESS) {
 			val = gen_expr_access_addr(ctx, operand);
 			val.type = expr->result;
 			return val;
 		}
 		struct gen_value val = mkgtemp(ctx, operand->result, ".%d");
 		struct qbe_value qv = mklval(ctx, &val);
 		struct qbe_value sz = constl(val.type->size);
 		enum qbe_instr alloc = alloc_for_align(val.type->align);
 		pushprei(ctx->current, &qv, alloc, &sz, NULL);
 		gen_expr_at(ctx, operand, val);
 		val.type = expr->result;
 		return val;
 	case UN_DEREF:
 		val = gen_expr(ctx, operand);
 		assert(type_dealias(val.type)->storage == STORAGE_POINTER);
 		val.type = type_dealias(val.type)->pointer.referent;
 		return gen_load(ctx, val);
 	case UN_BNOT:
 		val = gen_expr(ctx, operand);
 		temp = mkgtemp(ctx, operand->result, ".%d");
 		qval = mkqval(ctx, &val), qtmp = mkqval(ctx, &temp);
 		struct qbe_value ones = constl((uint64_t)-1);
 		pushi(ctx->current, &qtmp, Q_XOR, &qval, &ones, NULL);
 		return temp;
 	case UN_LNOT:
 		val = gen_expr(ctx, operand);
 		temp = mkgtemp(ctx, operand->result, ".%d");
 		qval = mkqval(ctx, &val), qtmp = mkqval(ctx, &temp);
 		struct qbe_value zerow = constw(0);
 		pushi(ctx->current, &qtmp, Q_CEQW, &qval, &zerow, NULL);
 		return temp;
 	case UN_MINUS:
 		val = gen_expr(ctx, operand);
 		temp = mkgtemp(ctx, operand->result, ".%d");
 		qval = mkqval(ctx, &val), qtmp = mkqval(ctx, &temp);
 		pushi(ctx->current, &qtmp, Q_NEG, &qval, NULL);
 		return temp;
 	case UN_PLUS:
 		return gen_expr(ctx, operand);
 	}
 	abort(); // Invariant
 }
 
 static struct gen_value
 gen_expr_vaarg(struct gen_context *ctx,
 	const struct expression *expr)
 {
 	// XXX: qbe only supports variadic base types, should check for this
 	struct gen_value result = mkgtemp(ctx, expr->result, ".%d");
 	struct qbe_value qresult = mkqval(ctx, &result);
 	struct gen_value ap = gen_expr(ctx, expr->vaarg.ap);
 	struct qbe_value qap = mkqval(ctx, &ap);
 	pushi(ctx->current, &qresult, Q_VAARG, &qap, NULL);
 	return result;
 }
 
 static void
 gen_expr_vastart_at(struct gen_context *ctx,
 	const struct expression *expr,
 	struct gen_value out)
 {
 	struct qbe_value base = mklval(ctx, &out);
 	pushi(ctx->current, NULL, Q_VASTART, &base, NULL);
 }
 
 static struct gen_value
 gen_expr(struct gen_context *ctx, const struct expression *expr)
 {
 	switch ((int)expr->type) {
 	case EXPR_ACCESS:
 		return gen_expr_access(ctx, expr);
 	case EXPR_ALLOC:
 		return gen_expr_alloc_with(ctx, expr, NULL);
 	case EXPR_APPEND:
 		return gen_expr_append(ctx, expr);
 	case EXPR_ASSERT:
 		return gen_expr_assert(ctx, expr);
 	case EXPR_ASSIGN:
 		return gen_expr_assign(ctx, expr);
 	case EXPR_BINARITHM:
 		return gen_expr_binarithm(ctx, expr);
 	case EXPR_BINDING:
 		return gen_expr_binding(ctx, expr);
 	case EXPR_BREAK:
 	case EXPR_CONTINUE:
 	case EXPR_YIELD:
 		return gen_expr_control(ctx, expr);
 	case EXPR_CALL:
 		return gen_expr_call(ctx, expr);
 	case EXPR_CAST:
 		return gen_expr_cast(ctx, expr);
 	case EXPR_COMPOUND:
 		return gen_expr_compound_with(ctx, expr, NULL);
 	case EXPR_CONSTANT:
 		return gen_expr_const(ctx, expr);
 	case EXPR_DEFER:
 		return gen_expr_defer(ctx, expr);
 	case EXPR_DELETE:
 		return gen_expr_delete(ctx, expr);
 	case EXPR_FOR:
 		return gen_expr_for(ctx, expr);
 	case EXPR_FREE:
 		return gen_expr_free(ctx, expr);
 	case EXPR_IF:
 		return gen_expr_if_with(ctx, expr, NULL);
 	case EXPR_INSERT:
 		return gen_expr_insert(ctx, expr);
 	case EXPR_MATCH:
 		return gen_expr_match_with(ctx, expr, NULL);
 	case EXPR_MEASURE:
 		return gen_expr_measure(ctx, expr);
 	case EXPR_PROPAGATE:
 		assert(0); // Lowered in check (for now?)
 	case EXPR_RETURN:
 		return gen_expr_return(ctx, expr);
 	case EXPR_SWITCH:
 		return gen_expr_switch_with(ctx, expr, NULL);
 	case EXPR_UNARITHM:
 		return gen_expr_unarithm(ctx, expr);
 	case EXPR_VAARG:
 		return gen_expr_vaarg(ctx, expr);
 	case EXPR_VAEND:
 		return gv_void; // no-op
 	case EXPR_SLICE:
 	case EXPR_STRUCT:
 	case EXPR_TUPLE:
 	case EXPR_VASTART:
 		break; // Prefers -at style
 	// gen-specific psuedo-expressions
 	case EXPR_GEN_VALUE:
 		return *(struct gen_value *)expr->user;
 	}
 
 	struct gen_value out = mkgtemp(ctx, expr->result, "object.%d");
 	struct qbe_value base = mkqval(ctx, &out);
 	struct qbe_value sz = constl(expr->result->size);
 	enum qbe_instr alloc = alloc_for_align(expr->result->align);
 	pushprei(ctx->current, &base, alloc, &sz, NULL);
 	gen_expr_at(ctx, expr, out);
 	return out;
 }
 
 static void
 gen_expr_at(struct gen_context *ctx,
 	const struct expression *expr,
 	struct gen_value out)
 {
 	assert(out.kind != GV_CONST);
 
 	switch (expr->type) {
 	case EXPR_ALLOC:
 		gen_expr_alloc_with(ctx, expr, &out);
 		return;
 	case EXPR_CAST:
 		gen_expr_cast_at(ctx, expr, out);
 		return;
 	case EXPR_COMPOUND:
 		gen_expr_compound_with(ctx, expr, &out);
 		return;
 	case EXPR_CONSTANT:
 		gen_expr_const_at(ctx, expr, out);
 		return;
 	case EXPR_IF:
 		gen_expr_if_with(ctx, expr, &out);
 		return;
 	case EXPR_MATCH:
 		gen_expr_match_with(ctx, expr, &out);
 		return;
 	case EXPR_SLICE:
 		gen_expr_slice_at(ctx, expr, out);
 		return;
 	case EXPR_STRUCT:
 		gen_expr_struct_at(ctx, expr, out);
 		return;
 	case EXPR_SWITCH:
 		gen_expr_switch_with(ctx, expr, &out);
 		return;
 	case EXPR_TUPLE:
 		gen_expr_tuple_at(ctx, expr, out);
 		return;
 	case EXPR_VASTART:
 		gen_expr_vastart_at(ctx, expr, out);
 		return;
 	default:
 		break; // Prefers non-at style
 	}
 
 	struct gen_value result = gen_expr(ctx, expr);
 	if (!expr->terminates) {
 		gen_store(ctx, out, result);
 	}
 }
 
 static struct gen_value
 gen_expr_with(struct gen_context *ctx,
 	const struct expression *expr,
 	struct gen_value *out)
 {
 	if (out) {
 		gen_expr_at(ctx, expr, *out);
 		return *out;
 	}
 	return gen_expr(ctx, expr);
 }
 
 static struct qbe_data_item *gen_data_item(struct gen_context *,
 	struct expression *, struct qbe_data_item *);
 
 static void
 gen_function_decl(struct gen_context *ctx, const struct declaration *decl)
 {
 	const struct function_decl *func = &decl->func;
 	const struct type *fntype = func->type;
 	if (func->body == NULL) {
 		return; // Prototype
 	}
 
 	struct qbe_def *qdef = xcalloc(1, sizeof(struct qbe_def));
 	qdef->kind = Q_FUNC;
 	qdef->exported = decl->exported;
 	ctx->current = &qdef->func;
 
 	qdef->name = decl->symbol ? xstrdup(decl->symbol)
 		: ident_to_sym(&decl->ident);
 
 	struct qbe_statement start_label = {0};
 	mklabel(ctx, &start_label, "start.%d");
 	push(&qdef->func.prelude, &start_label);
 
 	if (type_dealias(fntype->func.result)->storage != STORAGE_VOID) {
 		qdef->func.returns = qtype_lookup(
 			ctx, fntype->func.result, false);
 	} else {
 		qdef->func.returns = &qbe_void;
 	}
 	if (fntype->func.variadism == VARIADISM_C) {
 		qdef->func.variadic = true;
 	}
 
 	struct qbe_func_param *param, **next = &qdef->func.params;
 	for (struct scope_object *obj = decl->func.scope->objects;
 			obj; obj = obj->lnext) {
 		const struct type *type = obj->type;
 		param = *next = xcalloc(1, sizeof(struct qbe_func_param));
 		assert(!obj->ident.ns); // Invariant
 		param->name = xstrdup(obj->ident.name);
 		param->type = qtype_lookup(ctx, type, false);
 
 		struct gen_binding *gb =
 			xcalloc(1, sizeof(struct gen_binding));
 		gb->value.kind = GV_TEMP;
 		gb->value.type = type;
 		gb->object = obj;
 		if (type_is_aggregate(type)) {
 			// No need to copy to stack
 			gb->value.name = xstrdup(param->name);
 		} else {
 			gb->value.name = gen_name(&ctx->id, "param.%d");
 
 			struct qbe_value qv = mklval(ctx, &gb->value);
 			struct qbe_value sz = constl(type->size);
 			enum qbe_instr alloc = alloc_for_align(type->align);
 			pushprei(ctx->current, &qv, alloc, &sz, NULL);
 			struct gen_value src = {
 				.kind = GV_TEMP,
 				.type = type,
 				.name = param->name,
 			};
 			gen_store(ctx, gb->value, src);
 		}
 
 		gb->next = ctx->bindings;
 		ctx->bindings = gb;
 		next = &param->next;
 	}
 
 	pushl(&qdef->func, &ctx->id, "body.%d");
 	struct gen_value ret = gen_expr(ctx, decl->func.body);
 
 	if (decl->func.body->terminates) {
 		// XXX: This is a bit hacky, to appease qbe
 		size_t ln = ctx->current->body.ln;
 		struct qbe_statement *last = &ctx->current->body.stmts[ln - 1];
 		if (last->type != Q_INSTR || last->instr != Q_RET) {
 			pushi(ctx->current, NULL, Q_RET, NULL);
 		}
 	} else if (type_dealias(fntype->func.result)->storage != STORAGE_VOID) {
 		struct qbe_value qret = mkqval(ctx, &ret);
 		pushi(ctx->current, NULL, Q_RET, &qret, NULL);
 	} else {
 		pushi(ctx->current, NULL, Q_RET, NULL);
 	}
 
 	qbe_append_def(ctx->out, qdef);
 
 	if (func->flags & FN_INIT) {
 		struct qbe_def *init = xcalloc(1, sizeof *init);
 		init->kind = Q_DATA;
 		init->exported = false;
 		init->data.align = 8;
 		init->data.section = ".init_array";
 		init->data.secflags = NULL;
 
 		size_t n = snprintf(NULL, 0, ".init.%s", qdef->name);
 		init->name = xcalloc(n + 1, 1);
 		snprintf(init->name, n + 1, ".init.%s", qdef->name);
 
 		struct qbe_data_item dataitem = {
 			.type = QD_VALUE,
 			.value = {
 				.kind = QV_GLOBAL,
 				.type = &qbe_long,
 				.name = xstrdup(qdef->name),
 			},
 			.next = NULL,
 		};
 		init->data.items = dataitem;
 
 		qbe_append_def(ctx->out, init);
 	}
 
 	if (func->flags & FN_FINI) {
 		struct qbe_def *fini = xcalloc(1, sizeof *fini);
 		fini->kind = Q_DATA;
 		fini->exported = false;
 		fini->data.align = 8;
 		fini->data.section = ".fini_array";
 		fini->data.secflags = NULL;
 
 		size_t n = snprintf(NULL, 0, ".fini.%s", qdef->name);
 		fini->name = xcalloc(n + 1, 1);
 		snprintf(fini->name, n + 1, ".fini.%s", qdef->name);
 
 		struct qbe_data_item dataitem = {
 			.type = QD_VALUE,
 			.value = {
 				.kind = QV_GLOBAL,
 				.type = &qbe_long,
 				.name = xstrdup(qdef->name),
 			},
 			.next = NULL,
 		};
 		fini->data.items = dataitem;
 
 		qbe_append_def(ctx->out, fini);
 	}
 
 	if (func->flags & FN_TEST) {
 		struct qbe_def *test = xcalloc(1, sizeof *test);
 		test->kind = Q_DATA;
 		test->exported = false;
 		test->data.align = 8;
 		test->data.section = ".test_array";
 		test->data.secflags = "aw";
 
 		size_t n = snprintf(NULL, 0, ".test.%s", qdef->name);
 		test->name = xcalloc(n + 1, 1);
 		snprintf(test->name, n + 1, ".test.%s", qdef->name);
 
 		char *ident = identifier_unparse(&decl->ident);
 
 		struct qbe_data_item *dataitem = &test->data.items;
 		struct expression expr = {
 			.type = EXPR_CONSTANT,
 			.result = &builtin_type_str,
 			.constant = {
 				.object = NULL,
 				.string = {
 					.value = ident,
 					.len = strlen(ident),
 				},
 			},
 		};
 		dataitem = gen_data_item(ctx, &expr, dataitem);
 
 		struct qbe_data_item *next = xcalloc(1, sizeof *next);
 		next->type = QD_VALUE;
 		next->value.kind = QV_GLOBAL;
 		next->value.type = &qbe_long;
 		next->value.name = xstrdup(qdef->name);
 		next->next = NULL;
 		dataitem->next = next;
 
 		qbe_append_def(ctx->out, test);
 	}
 
 	ctx->current = NULL;
 }
 
 static struct qbe_data_item *
 gen_data_item(struct gen_context *ctx, struct expression *expr,
 	struct qbe_data_item *item)
 {
 	assert(expr->type == EXPR_CONSTANT);
 
 	struct qbe_def *def;
 	const struct expression_constant *constant = &expr->constant;
 	const struct type *type = type_dealias(expr->result);
 	if (type->storage == STORAGE_ENUM) {
 		type = type->alias.type;
 	}
 	type = lower_const(type, NULL);
 	if (constant->object) {
 		item->type = QD_SYMOFFS;
 		item->sym = ident_to_sym(&constant->object->ident);
 		item->offset = constant->ival;
 		return item;
 	}
 
 	switch (type->storage) {
 	case STORAGE_I8:
 	case STORAGE_U8:
 	case STORAGE_CHAR:
 		item->type = QD_VALUE;
 		item->value = constw((uint8_t)constant->uval);
 		item->value.type = &qbe_byte;
 		break;
 	case STORAGE_BOOL:
 		item->type = QD_VALUE;
 		item->value = constw(constant->bval ? 1 : 0);
 		item->value.type = &qbe_byte;
 		break;
 	case STORAGE_I16:
 	case STORAGE_U16:
 		item->type = QD_VALUE;
 		item->value = constw((uint16_t)constant->uval);
 		item->value.type = &qbe_half;
 		break;
 	case STORAGE_I32:
 	case STORAGE_U32:
 	case STORAGE_INT:
 	case STORAGE_UINT:
 	case STORAGE_RUNE:
 		item->type = QD_VALUE;
 		item->value = constw((uint32_t)constant->uval);
 		break;
 	case STORAGE_U64:
 	case STORAGE_I64:
 	case STORAGE_SIZE:
 		item->type = QD_VALUE;
 		item->value = constl((uint64_t)constant->uval);
 		break;
 	case STORAGE_F32:
 		item->type = QD_VALUE;
 		item->value = consts((float)constant->fval);
 		break;
 	case STORAGE_F64:
 		item->type = QD_VALUE;
 		item->value = constd((double)constant->fval);
 		break;
 	case STORAGE_UINTPTR:
 	case STORAGE_POINTER:
 		item->type = QD_VALUE;
 		switch (ctx->arch.ptr->stype) {
 		case Q_LONG:
 			item->value = constl((uint64_t)constant->uval);
 			break;
 		default: assert(0);
 		}
 		break;
 	case STORAGE_ARRAY:
 		assert(type->array.length != SIZE_UNDEFINED);
 		size_t n = type->array.length;
 		for (struct array_constant *c = constant->array;
 				c && n; c = c->next ? c->next : c, --n) {
 			item = gen_data_item(ctx, c->value, item);
 			if (n > 1 || c->next) {
 				item->next = xcalloc(1,
 					sizeof(struct qbe_data_item));
 				item = item->next;
 			}
 		}
 		break;
 	case STORAGE_STRING:
 		def = xcalloc(1, sizeof(struct qbe_def));
 		def->name = gen_name(&ctx->id, "strdata.%d");
 		def->kind = Q_DATA;
 		def->data.align = ALIGN_UNDEFINED;
 		def->data.items.type = QD_STRING;
 		def->data.items.str = xcalloc(1, expr->constant.string.len);
 		def->data.items.sz = expr->constant.string.len;
 		memcpy(def->data.items.str, expr->constant.string.value,
 			expr->constant.string.len);
 
 		item->type = QD_VALUE;
 		if (expr->constant.string.len != 0) {
 			qbe_append_def(ctx->out, def);
 			item->value.kind = QV_GLOBAL;
 			item->value.type = &qbe_long;
 			item->value.name = xstrdup(def->name);
 		} else {
 			free(def);
 			item->value = constl(0);
 		}
 
 		item->next = xcalloc(1, sizeof(struct qbe_data_item));
 		item = item->next;
 		item->type = QD_VALUE;
 		item->value = constl(expr->constant.string.len);
 		item->next = xcalloc(1, sizeof(struct qbe_data_item));
 		item = item->next;
 		item->type = QD_VALUE;
 		item->value = constl(expr->constant.string.len);
 		break;
 	case STORAGE_SLICE:
 		def = xcalloc(1, sizeof(struct qbe_def));
 		def->name = gen_name(&ctx->id, "sldata.%d");
 		def->kind = Q_DATA;
 		def->data.align = ALIGN_UNDEFINED;
 
 		size_t len = 0;
 		struct qbe_data_item *subitem = &def->data.items;
 		for (struct array_constant *c = constant->array;
 				c; c = c->next) {
 			subitem = gen_data_item(ctx, c->value, subitem);
 			if (c->next) {
 				subitem->next = xcalloc(1,
 					sizeof(struct qbe_data_item));
 				subitem = subitem->next;
 			}
 			++len;
 		}
 
 		item->type = QD_VALUE;
 		if (len != 0) {
 			qbe_append_def(ctx->out, def);
 			item->value.kind = QV_GLOBAL;
 			item->value.type = &qbe_long;
 			item->value.name = xstrdup(def->name);
 		} else {
 			free(def);
 			item->value = constl(0);
 		}
 
 		item->next = xcalloc(1, sizeof(struct qbe_data_item));
 		item = item->next;
 		item->type = QD_VALUE;
 		item->value = constl(len);
 		item->next = xcalloc(1, sizeof(struct qbe_data_item));
 		item = item->next;
 		item->type = QD_VALUE;
 		item->value = constl(len);
 		break;
 	case STORAGE_STRUCT:
 		for (struct struct_constant *f = constant->_struct;
 				f; f = f->next) {
 			item = gen_data_item(ctx, f->value, item);
 			if (f->next) {
 				const struct struct_field *f1 = f->field;
 				const struct struct_field *f2 = f->next->field;
 				if (f2->offset != f1->offset + f1->type->size) {
 					item->next = xcalloc(1,
 						sizeof(struct qbe_data_item));
 					item = item->next;
 					item->type = QD_ZEROED;
 					item->zeroed = f2->offset -
 						(f1->offset + f1->type->size);
 				}
 
 				item->next = xcalloc(1,
 					sizeof(struct qbe_data_item));
 				item = item->next;
 			} else {
 				const struct struct_field *fi = f->field;
 				if (fi->offset + fi->type->size
 						!= expr->result->size) {
 					item->next = xcalloc(1,
 						sizeof(struct qbe_data_item));
 					item = item->next;
 					item->type = QD_ZEROED;
 					item->zeroed = expr->result->size
 						- (fi->offset + fi->type->size);
 				}
 			}
 		}
 		break;
 	case STORAGE_TUPLE:
 		for (const struct tuple_constant *tuple = constant->tuple;
 				tuple; tuple = tuple->next) {
 			item = gen_data_item(ctx, tuple->value, item);
 			if (tuple->next) {
 				const struct type_tuple *f1 = tuple->field;
 				const struct type_tuple *f2 = tuple->next->field;
 				if (f2->offset != f1->offset + f1->type->size) {
 					item->next = xcalloc(1,
 						sizeof(struct qbe_data_item));
 					item = item->next;
 					item->type = QD_ZEROED;
 					item->zeroed = f2->offset -
 						(f1->offset + f1->type->size);
 				}
 
 
 				item->next = xcalloc(1,
 					sizeof(struct qbe_data_item));
 				item = item->next;
 			} else {
 				const struct type_tuple *fi = tuple->field;
 				if (fi->offset + fi->type->size
 						!= expr->result->size) {
 					item->next = xcalloc(1,
 						sizeof(struct qbe_data_item));
 					item = item->next;
 					item->type = QD_ZEROED;
 					item->zeroed = expr->result->size
 						- (fi->offset + fi->type->size);
 				}
 			}
 		}
 		break;
 	case STORAGE_TAGGED:
 		item->type = QD_VALUE;
 		item->value = constw((uint32_t)constant->tagged.tag->id);
 		if (type->align != builtin_type_uint.align) {
 			item->next = xcalloc(1, sizeof(struct qbe_data_item));
 			item = item->next;
 			item->type = QD_ZEROED;
 			item->zeroed = type->align - builtin_type_uint.align;
 		}
 		if (constant->tagged.tag->size != 0) {
 			item->next = xcalloc(1, sizeof(struct qbe_data_item));
 			item = item->next;
 			item = gen_data_item(ctx, constant->tagged.value, item);
 		}
 		if (constant->tagged.tag->size < type->size - type->align) {
 			item->next = xcalloc(1, sizeof(struct qbe_data_item));
 			item = item->next;
 			item->type = QD_ZEROED;
 			item->zeroed = type->size - type->align - constant->tagged.tag->size;
 		}
 		break;
 	case STORAGE_ENUM:
 	case STORAGE_UNION:
 	case STORAGE_ALIAS:
 	case STORAGE_ERROR:
 	case STORAGE_FCONST:
 	case STORAGE_FUNCTION:
 	case STORAGE_ICONST:
 	case STORAGE_RCONST:
 	case STORAGE_NULL:
 	case STORAGE_VALIST:
 	case STORAGE_VOID:
 		assert(0); // Invariant
 	}
 
 	assert(item->type != QD_VALUE || item->value.type);
 	return item;
 }
 
 static void
 gen_global_decl(struct gen_context *ctx, const struct declaration *decl)
 {
 	assert(decl->type == DECL_GLOBAL);
 	const struct global_decl *global = &decl->global;
 	if (!global->value) {
 		return; // Forward declaration
 	}
 	struct qbe_def *qdef = xcalloc(1, sizeof(struct qbe_def));
 	qdef->kind = Q_DATA;
 	qdef->data.align = ALIGN_UNDEFINED;
 	qdef->data.threadlocal = global->threadlocal;
 	qdef->exported = decl->exported;
 	qdef->name = ident_to_sym(&decl->ident);
 	gen_data_item(ctx, global->value, &qdef->data.items);
 	qbe_append_def(ctx->out, qdef);
 }
 
 static void
 gen_decl(struct gen_context *ctx, const struct declaration *decl)
 {
 	switch (decl->type) {
 	case DECL_FUNC:
 		gen_function_decl(ctx, decl);
 		break;
 	case DECL_GLOBAL:
 		gen_global_decl(ctx, decl);
 		break;
 	case DECL_TYPE:
 	case DECL_CONST:
 		break; // no-op
 	}
 }
 
 void
 gen(const struct unit *unit, struct type_store *store, struct qbe_program *out)
 {
 	struct gen_context ctx = {
 		.out = out,
 		.store = store,
 		.ns = unit->ns,
 		.arch = {
 			.ptr = &qbe_long,
 			.sz = &qbe_long,
 		},
 	};
 	ctx.out->next = &ctx.out->defs;
 	const struct declarations *decls = unit->declarations;
 	while (decls) {
 		gen_decl(&ctx, decls->decl);
 		decls = decls->next;
 	}
 }