bshell/bshell.runtime/compile/label.c

#include "compile-node.h"

size_t compile_declare_label(struct compile_ctx *ctx)
{
	size_t id = ctx->c_labels.count;
	struct compile_label *label = fx_vector_emplace_back(
		ctx->c_labels,
		NULL);
	return id;
}

void compile_define_label(struct compile_ctx *ctx, size_t label_id)
{
	size_t offset = 0;
	bshell_scriptblock_get_text(ctx->c_block, NULL, &offset);
	offset *= sizeof(bshell_instruction);
	ctx->c_labels.items[label_id].l_ip = offset;
}

void compile_ref_label(struct compile_ctx *ctx, size_t label_id)
{
	struct compile_label_ref *ref = malloc(sizeof *ref);
	if (!ref) {
		return;
	}

	memset(ref, 0x0, sizeof *ref);
	ref->ref_label_id = label_id;
	bshell_scriptblock_get_text(ctx->c_block, NULL, &ref->ref_offset);
	ref->ref_offset *= sizeof(bshell_instruction);
	fx_queue_push_back(&ctx->c_label_refs, &ref->ref_entry);
}

enum bshell_status compile_resolve_labels(struct compile_ctx *ctx)
{
	fx_queue_entry *cur = fx_queue_pop_front(&ctx->c_label_refs);
	while (cur) {
		struct compile_label_ref *ref = fx_unbox(
			struct compile_label_ref,
			cur,
			ref_entry);
		struct compile_label *label = &ctx->c_labels.items
		                                       [ref->ref_label_id];

		long long rel_value = (long long)label->l_ip
		                    - (long long)ref->ref_offset;

		enum bshell_opcode op;
		uint32_t arg;
		bshell_scriptblock_read_instruction(
			ctx->c_block,
			ref->ref_offset,
			&op,
			&arg);
		arg = (uint32_t)rel_value;
		bshell_scriptblock_patch_instruction(
			ctx->c_block,
			ref->ref_offset,
			op,
			arg);

		free(ref);
		cur = fx_queue_pop_front(&ctx->c_label_refs);
	}

	return BSHELL_SUCCESS;
}