tools: bpftool: partition basic-block for each function in the CFG (0824611f) · Commits · 戴 / test

tools/bpf/bpftool/cfg.c

+117 −1

Original line number	Diff line number	Diff line
		@@ -49,17 +49,32 @@ struct cfg {

		struct func_node {
		struct list_head l;
		struct list_head bbs;
		struct bpf_insn *start;
		struct bpf_insn *end;
		int idx;
		int bb_num;
		};

		struct bb_node {
		struct list_head l;
		struct bpf_insn *head;
		struct bpf_insn *tail;
		int idx;
		};

		#define func_prev(func) list_prev_entry(func, l)
		#define func_next(func) list_next_entry(func, l)
		#define bb_prev(bb) list_prev_entry(bb, l)
		#define bb_next(bb) list_next_entry(bb, l)
		#define cfg_first_func(cfg) \
		list_first_entry(&cfg->funcs, struct func_node, l)
		#define cfg_last_func(cfg) \
		list_last_entry(&cfg->funcs, struct func_node, l)
		#define func_first_bb(func) \
		list_first_entry(&func->bbs, struct bb_node, l)
		#define func_last_bb(func) \
		list_last_entry(&func->bbs, struct bb_node, l)

		static struct func_node cfg_append_func(struct cfg cfg, struct bpf_insn *insn)
		{
		@@ -86,6 +101,30 @@ static struct func_node cfg_append_func(struct cfg cfg, struct bpf_insn *insn)
		return new_func;
		}

		static struct bb_node func_append_bb(struct func_node func,
		struct bpf_insn *insn)
		{
		struct bb_node new_bb, bb;

		list_for_each_entry(bb, &func->bbs, l) {
		if (bb->head == insn)
		return bb;
		else if (bb->head > insn)
		break;
		}

		bb = bb_prev(bb);
		new_bb = calloc(1, sizeof(*new_bb));
		if (!new_bb) {
		p_err("OOM when allocating BB node");
		return NULL;
		}
		new_bb->head = insn;
		list_add(&new_bb->l, &bb->l);

		return new_bb;
		}

		static bool cfg_partition_funcs(struct cfg cfg, struct bpf_insn cur,
		struct bpf_insn *end)
		{
		@@ -115,13 +154,83 @@ static bool cfg_partition_funcs(struct cfg cfg, struct bpf_insn cur,
		return false;
		}

		static bool func_partition_bb_head(struct func_node *func)
		{
		struct bpf_insn cur, end;
		struct bb_node *bb;

		cur = func->start;
		end = func->end;
		INIT_LIST_HEAD(&func->bbs);
		bb = func_append_bb(func, cur);
		if (!bb)
		return true;

		for (; cur <= end; cur++) {
		if (BPF_CLASS(cur->code) == BPF_JMP) {
		u8 opcode = BPF_OP(cur->code);

		if (opcode == BPF_EXIT \|\| opcode == BPF_CALL)
		continue;

		bb = func_append_bb(func, cur + cur->off + 1);
		if (!bb)
		return true;

		if (opcode != BPF_JA) {
		bb = func_append_bb(func, cur + 1);
		if (!bb)
		return true;
		}
		}
		}

		return false;
		}

		static void func_partition_bb_tail(struct func_node *func)
		{
		struct bb_node bb, last;
		unsigned int bb_idx = 0;

		last = func_last_bb(func);
		last->tail = func->end;
		bb = func_first_bb(func);
		list_for_each_entry_from(bb, &last->l, l) {
		bb->tail = bb_next(bb)->head - 1;
		bb->idx = bb_idx++;
		}

		last->idx = bb_idx++;
		func->bb_num = bb_idx;
		}

		static bool func_partition_bb(struct func_node *func)
		{
		if (func_partition_bb_head(func))
		return true;

		func_partition_bb_tail(func);

		return false;
		}

		static bool cfg_build(struct cfg cfg, struct bpf_insn insn, unsigned int len)
		{
		int cnt = len / sizeof(*insn);
		struct func_node *func;

		INIT_LIST_HEAD(&cfg->funcs);

		return cfg_partition_funcs(cfg, insn, insn + cnt);
		if (cfg_partition_funcs(cfg, insn, insn + cnt))
		return true;

		list_for_each_entry(func, &cfg->funcs, l) {
		if (func_partition_bb(func))
		return true;
		}

		return false;
		}

		static void cfg_destroy(struct cfg *cfg)
		@@ -129,6 +238,13 @@ static void cfg_destroy(struct cfg *cfg)
		struct func_node func, func2;

		list_for_each_entry_safe(func, func2, &cfg->funcs, l) {
		struct bb_node bb, bb2;

		list_for_each_entry_safe(bb, bb2, &func->bbs, l) {
		list_del(&bb->l);
		free(bb);
		}

		list_del(&func->l);
		free(func);
		}

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