/*
 * Copyright (C) 2009-2011, Frederic Weisbecker <fweisbec@gmail.com>
 *
 * Handle the callchains from the stream in an ad-hoc radix tree and then
 * sort them in an rbtree.
 *
 * Using a radix for code path provides a fast retrieval and factorizes
 * memory use. Also that lets us use the paths in a hierarchical graph view.
 *
 */

#include <stdlib.h>
#include <stdio.h>
#include <stdbool.h>
#include <errno.h>
#include <math.h>

#include "asm/bug.h"

#include "hist.h"
#include "util.h"
#include "sort.h"
#include "machine.h"
#include "callchain.h"

__thread struct callchain_cursor callchain_cursor;

int
parse_callchain_report_opt(const char *arg)
{
        char *tok, *tok2;
        char *endptr;

        symbol_conf.use_callchain = true;

        if (!arg)
                return 0;

        tok = strtok((char *)arg, ",");
        if (!tok)
                return -1;

        /* get the output mode */
        if (!strncmp(tok, "graph", strlen(arg))) {
                callchain_param.mode = CHAIN_GRAPH_ABS;

        } else if (!strncmp(tok, "flat", strlen(arg))) {
                callchain_param.mode = CHAIN_FLAT;
        } else if (!strncmp(tok, "fractal", strlen(arg))) {
                callchain_param.mode = CHAIN_GRAPH_REL;
        } else if (!strncmp(tok, "none", strlen(arg))) {
                callchain_param.mode = CHAIN_NONE;
                symbol_conf.use_callchain = false;
                return 0;
        } else {
                return -1;
        }

        /* get the min percentage */
        tok = strtok(NULL, ",");
        if (!tok)
                goto setup;

        callchain_param.min_percent = strtod(tok, &endptr);
        if (tok == endptr)
                return -1;

        /* get the print limit */
        tok2 = strtok(NULL, ",");
        if (!tok2)
                goto setup;

        if (tok2[0] != 'c') {
                callchain_param.print_limit = strtoul(tok2, &endptr, 0);
                tok2 = strtok(NULL, ",");
                if (!tok2)
                        goto setup;
        }

        /* get the call chain order */
        if (!strncmp(tok2, "caller", strlen("caller")))
                callchain_param.order = ORDER_CALLER;
        else if (!strncmp(tok2, "callee", strlen("callee")))
                callchain_param.order = ORDER_CALLEE;
        else
                return -1;

        /* Get the sort key */
        tok2 = strtok(NULL, ",");
        if (!tok2)
                goto setup;
        if (!strncmp(tok2, "function", strlen("function")))
                callchain_param.key = CCKEY_FUNCTION;
        else if (!strncmp(tok2, "address", strlen("address")))
                callchain_param.key = CCKEY_ADDRESS;
        else
                return -1;
setup:
        if (callchain_register_param(&callchain_param) < 0) {
                pr_err("Can't register callchain params\n");
                return -1;
        }
        return 0;
}

static void
rb_insert_callchain(struct rb_root *root, struct callchain_node *chain,
                    enum chain_mode mode)
{
        struct rb_node **p = &root->rb_node;
        struct rb_node *parent = NULL;
        struct callchain_node *rnode;
        u64 chain_cumul = callchain_cumul_hits(chain);

        while (*p) {
                u64 rnode_cumul;

                parent = *p;
                rnode = rb_entry(parent, struct callchain_node, rb_node);
                rnode_cumul = callchain_cumul_hits(rnode);

                switch (mode) {
                case CHAIN_FLAT:
                        if (rnode->hit < chain->hit)
                                p = &(*p)->rb_left;
                        else
                                p = &(*p)->rb_right;
                        break;
                case CHAIN_GRAPH_ABS: /* Falldown */
                case CHAIN_GRAPH_REL:
                        if (rnode_cumul < chain_cumul)
                                p = &(*p)->rb_left;
                        else
                                p = &(*p)->rb_right;
                        break;
                case CHAIN_NONE:
                default:
                        break;
                }
        }

        rb_link_node(&chain->rb_node, parent, p);
        rb_insert_color(&chain->rb_node, root);
}

static void
__sort_chain_flat(struct rb_root *rb_root, struct callchain_node *node,
                  u64 min_hit)
{
        struct rb_node *n;
        struct callchain_node *child;

        n = rb_first(&node->rb_root_in);
        while (n) {
                child = rb_entry(n, struct callchain_node, rb_node_in);
                n = rb_next(n);

                __sort_chain_flat(rb_root, child, min_hit);
        }

        if (node->hit && node->hit >= min_hit)
                rb_insert_callchain(rb_root, node, CHAIN_FLAT);
}

/*
 * Once we get every callchains from the stream, we can now
 * sort them by hit
 */
static void
sort_chain_flat(struct rb_root *rb_root, struct callchain_root *root,
                u64 min_hit, struct callchain_param *param __maybe_unused)
{
        __sort_chain_flat(rb_root, &root->node, min_hit);
}

static void __sort_chain_graph_abs(struct callchain_node *node,
                                   u64 min_hit)
{
        struct rb_node *n;
        struct callchain_node *child;

        node->rb_root = RB_ROOT;
        n = rb_first(&node->rb_root_in);

        while (n) {
                child = rb_entry(n, struct callchain_node, rb_node_in);
                n = rb_next(n);

                __sort_chain_graph_abs(child, min_hit);
                if (callchain_cumul_hits(child) >= min_hit)
                        rb_insert_callchain(&node->rb_root, child,
                                            CHAIN_GRAPH_ABS);
        }
}

static void
sort_chain_graph_abs(struct rb_root *rb_root, struct callchain_root *chain_root,
                     u64 min_hit, struct callchain_param *param __maybe_unused)
{
        __sort_chain_graph_abs(&chain_root->node, min_hit);
        rb_root->rb_node = chain_root->node.rb_root.rb_node;
}

static void __sort_chain_graph_rel(struct callchain_node *node,
                                   double min_percent)
{
        struct rb_node *n;
        struct callchain_node *child;
        u64 min_hit;

        node->rb_root = RB_ROOT;
        min_hit = ceil(node->children_hit * min_percent);

        n = rb_first(&node->rb_root_in);
        while (n) {
                child = rb_entry(n, struct callchain_node, rb_node_in);
                n = rb_next(n);

                __sort_chain_graph_rel(child, min_percent);
                if (callchain_cumul_hits(child) >= min_hit)
                        rb_insert_callchain(&node->rb_root, child,
                                            CHAIN_GRAPH_REL);
        }
}

static void
sort_chain_graph_rel(struct rb_root *rb_root, struct callchain_root *chain_root,
                     u64 min_hit __maybe_unused, struct callchain_param *param)
{
        __sort_chain_graph_rel(&chain_root->node, param->min_percent / 100.0);
        rb_root->rb_node = chain_root->node.rb_root.rb_node;
}

int callchain_register_param(struct callchain_param *param)
{
        switch (param->mode) {
        case CHAIN_GRAPH_ABS:
                param->sort = sort_chain_graph_abs;
                break;
        case CHAIN_GRAPH_REL:
                param->sort = sort_chain_graph_rel;
                break;
        case CHAIN_FLAT:
                param->sort = sort_chain_flat;
                break;
        case CHAIN_NONE:
        default:
                return -1;
        }
        return 0;
}

/*
 * Create a child for a parent. If inherit_children, then the new child
 * will become the new parent of it's parent children
 */
static struct callchain_node *
create_child(struct callchain_node *parent, bool inherit_children)
{
        struct callchain_node *new;

        new = zalloc(sizeof(*new));
        if (!new) {
                perror("not enough memory to create child for code path tree");
                return NULL;
        }
        new->parent = parent;
        INIT_LIST_HEAD(&new->val);

        if (inherit_children) {
                struct rb_node *n;
                struct callchain_node *child;

                new->rb_root_in = parent->rb_root_in;
                parent->rb_root_in = RB_ROOT;

                n = rb_first(&new->rb_root_in);
                while (n) {
                        child = rb_entry(n, struct callchain_node, rb_node_in);
                        child->parent = new;
                        n = rb_next(n);
                }

                /* make it the first child */
                rb_link_node(&new->rb_node_in, NULL, &parent->rb_root_in.rb_node);
                rb_insert_color(&new->rb_node_in, &parent->rb_root_in);
        }

        return new;
}


/*
 * Fill the node with callchain values
 */
static void
fill_node(struct callchain_node *node, struct callchain_cursor *cursor)
{
        struct callchain_cursor_node *cursor_node;

        node->val_nr = cursor->nr - cursor->pos;
        if (!node->val_nr)
                pr_warning("Warning: empty node in callchain tree\n");

        cursor_node = callchain_cursor_current(cursor);

        while (cursor_node) {
                struct callchain_list *call;

                call = zalloc(sizeof(*call));
                if (!call) {
                        perror("not enough memory for the code path tree");
                        return;
                }
                call->ip = cursor_node->ip;
                call->ms.sym = cursor_node->sym;
                call->ms.map = cursor_node->map;
                list_add_tail(&call->list, &node->val);

                callchain_cursor_advance(cursor);
                cursor_node = callchain_cursor_current(cursor);
        }
}

static struct callchain_node *
add_child(struct callchain_node *parent,
          struct callchain_cursor *cursor,
          u64 period)
{
        struct callchain_node *new;

        new = create_child(parent, false);
        fill_node(new, cursor);

        new->children_hit = 0;
        new->hit = period;
        return new;
}

static s64 match_chain(struct callchain_cursor_node *node,
                      struct callchain_list *cnode)
{
        struct symbol *sym = node->sym;

        if (cnode->ms.sym && sym &&
            callchain_param.key == CCKEY_FUNCTION)
                return cnode->ms.sym->start - sym->start;
        else
                return cnode->ip - node->ip;
}

/*
 * Split the parent in two parts (a new child is created) and
 * give a part of its callchain to the created child.
 * Then create another child to host the given callchain of new branch
 */
static void
split_add_child(struct callchain_node *parent,
                struct callchain_cursor *cursor,
                struct callchain_list *to_split,
                u64 idx_parents, u64 idx_local, u64 period)
{
        struct callchain_node *new;
        struct list_head *old_tail;
        unsigned int idx_total = idx_parents + idx_local;

        /* split */
        new = create_child(parent, true);

        /* split the callchain and move a part to the new child */
        old_tail = parent->val.prev;
        list_del_range(&to_split->list, old_tail);
        new->val.next = &to_split->list;
        new->val.prev = old_tail;
        to_split->list.prev = &new->val;
        old_tail->next = &new->val;

        /* split the hits */
        new->hit = parent->hit;
        new->children_hit = parent->children_hit;
        parent->children_hit = callchain_cumul_hits(new);
        new->val_nr = parent->val_nr - idx_local;
        parent->val_nr = idx_local;

        /* create a new child for the new branch if any */
        if (idx_total < cursor->nr) {
                struct callchain_node *first;
                struct callchain_list *cnode;
                struct callchain_cursor_node *node;
                struct rb_node *p, **pp;

                parent->hit = 0;
                parent->children_hit += period;

                node = callchain_cursor_current(cursor);
                new = add_child(parent, cursor, period);

                /*
                 * This is second child since we moved parent's children
                 * to new (first) child above.
                 */
                p = parent->rb_root_in.rb_node;
                first = rb_entry(p, struct callchain_node, rb_node_in);
                cnode = list_first_entry(&first->val, struct callchain_list,
                                         list);

                if (match_chain(node, cnode) < 0)
                        pp = &p->rb_left;
                else
                        pp = &p->rb_right;

                rb_link_node(&new->rb_node_in, p, pp);
                rb_insert_color(&new->rb_node_in, &parent->rb_root_in);
        } else {
                parent->hit = period;
        }
}

static int
append_chain(struct callchain_node *root,
             struct callchain_cursor *cursor,
             u64 period);

static void
append_chain_children(struct callchain_node *root,
                      struct callchain_cursor *cursor,
                      u64 period)
{
        struct callchain_node *rnode;
        struct callchain_cursor_node *node;
        struct rb_node **p = &root->rb_root_in.rb_node;
        struct rb_node *parent = NULL;

        node = callchain_cursor_current(cursor);
        if (!node)
                return;

        /* lookup in childrens */
        while (*p) {
                s64 ret;

                parent = *p;
                rnode = rb_entry(parent, struct callchain_node, rb_node_in);

                /* If at least first entry matches, rely to children */
                ret = append_chain(rnode, cursor, period);
                if (ret == 0)
                        goto inc_children_hit;

                if (ret < 0)
                        p = &parent->rb_left;
                else
                        p = &parent->rb_right;
        }
        /* nothing in children, add to the current node */
        rnode = add_child(root, cursor, period);
        rb_link_node(&rnode->rb_node_in, parent, p);
        rb_insert_color(&rnode->rb_node_in, &root->rb_root_in);

inc_children_hit:
        root->children_hit += period;
}

static int
append_chain(struct callchain_node *root,
             struct callchain_cursor *cursor,
             u64 period)
{
        struct callchain_list *cnode;
        u64 start = cursor->pos;
        bool found = false;
        u64 matches;
        int cmp = 0;

        /*
         * Lookup in the current node
         * If we have a symbol, then compare the start to match
         * anywhere inside a function, unless function
         * mode is disabled.
         */
        list_for_each_entry(cnode, &root->val, list) {
                struct callchain_cursor_node *node;

                node = callchain_cursor_current(cursor);
                if (!node)
                        break;

                cmp = match_chain(node, cnode);
                if (cmp)
                        break;

                found = true;

                callchain_cursor_advance(cursor);
        }

        /* matches not, relay no the parent */
        if (!found) {
                WARN_ONCE(!cmp, "Chain comparison error\n");
                return cmp;
        }

        matches = cursor->pos - start;

        /* we match only a part of the node. Split it and add the new chain */
        if (matches < root->val_nr) {
                split_add_child(root, cursor, cnode, start, matches, period);
                return 0;
        }

        /* we match 100% of the path, increment the hit */
        if (matches == root->val_nr && cursor->pos == cursor->nr) {
                root->hit += period;
                return 0;
        }

        /* We match the node and still have a part remaining */
        append_chain_children(root, cursor, period);

        return 0;
}

int callchain_append(struct callchain_root *root,
                     struct callchain_cursor *cursor,
                     u64 period)
{
        if (!cursor->nr)
                return 0;

        callchain_cursor_commit(cursor);

        append_chain_children(&root->node, cursor, period);

        if (cursor->nr > root->max_depth)
                root->max_depth = cursor->nr;

        return 0;
}

static int
merge_chain_branch(struct callchain_cursor *cursor,
                   struct callchain_node *dst, struct callchain_node *src)
{
        struct callchain_cursor_node **old_last = cursor->last;
        struct callchain_node *child;
        struct callchain_list *list, *next_list;
        struct rb_node *n;
        int old_pos = cursor->nr;
        int err = 0;

        list_for_each_entry_safe(list, next_list, &src->val, list) {
                callchain_cursor_append(cursor, list->ip,
                                        list->ms.map, list->ms.sym);
                list_del(&list->list);
                free(list);
        }

        if (src->hit) {
                callchain_cursor_commit(cursor);
                append_chain_children(dst, cursor, src->hit);
        }

        n = rb_first(&src->rb_root_in);
        while (n) {
                child = container_of(n, struct callchain_node, rb_node_in);
                n = rb_next(n);
                rb_erase(&child->rb_node_in, &src->rb_root_in);

                err = merge_chain_branch(cursor, dst, child);
                if (err)
                        break;

                free(child);
        }

        cursor->nr = old_pos;
        cursor->last = old_last;

        return err;
}

int callchain_merge(struct callchain_cursor *cursor,
                    struct callchain_root *dst, struct callchain_root *src)
{
        return merge_chain_branch(cursor, &dst->node, &src->node);
}

int callchain_cursor_append(struct callchain_cursor *cursor,
                            u64 ip, struct map *map, struct symbol *sym)
{
        struct callchain_cursor_node *node = *cursor->last;

        if (!node) {
                node = calloc(1, sizeof(*node));
                if (!node)
                        return -ENOMEM;

                *cursor->last = node;
        }

        node->ip = ip;
        node->map = map;
        node->sym = sym;

        cursor->nr++;

        cursor->last = &node->next;

        return 0;
}

int sample__resolve_callchain(struct perf_sample *sample, struct symbol **parent,
                              struct perf_evsel *evsel, struct addr_location *al,
                              int max_stack)
{
        if (sample->callchain == NULL)
                return 0;

        if (symbol_conf.use_callchain || symbol_conf.cumulate_callchain ||
            sort__has_parent) {
                return machine__resolve_callchain(al->machine, evsel, al->thread,
                                                  sample, parent, al, max_stack);
        }
        return 0;
}

int hist_entry__append_callchain(struct hist_entry *he, struct perf_sample *sample)
{
        if (!symbol_conf.use_callchain || sample->callchain == NULL)
                return 0;
        return callchain_append(he->callchain, &callchain_cursor, sample->period);
}

int fill_callchain_info(struct addr_location *al, struct callchain_cursor_node *node,
                        bool hide_unresolved)
{
        al->map = node->map;
        al->sym = node->sym;
        if (node->map)
                al->addr = node->map->map_ip(node->map, node->ip);
        else
                al->addr = node->ip;

        if (al->sym == NULL) {
                if (hide_unresolved)
                        return 0;
                if (al->map == NULL)
                        goto out;
        }

        if (al->map->groups == &al->machine->kmaps) {
                if (machine__is_host(al->machine)) {
                        al->cpumode = PERF_RECORD_MISC_KERNEL;
                        al->level = 'k';
                } else {
                        al->cpumode = PERF_RECORD_MISC_GUEST_KERNEL;
                        al->level = 'g';
                }
        } else {
                if (machine__is_host(al->machine)) {
                        al->cpumode = PERF_RECORD_MISC_USER;
                        al->level = '.';
                } else if (perf_guest) {
                        al->cpumode = PERF_RECORD_MISC_GUEST_USER;
                        al->level = 'u';
                } else {
                        al->cpumode = PERF_RECORD_MISC_HYPERVISOR;
                        al->level = 'H';
                }
        }

out:
        return 1;
}