/*
* %CopyrightBegin%
*
* Copyright Ericsson AB 2012-2018. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* %CopyrightEnd%
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include "sys.h"
#include "erl_vm.h"
#include "global.h"
#include "beam_load.h"
#include "erl_unicode.h"
typedef struct {
BeamInstr* start; /* Pointer to start of module. */
erts_atomic_t end; /* (BeamInstr*) Points one word beyond last function in module. */
} Range;
/*
* Used for crash dumping of literals. The size of erts_dump_lit_areas is
* always twice the number of active ranges (to allow for literals in both
* current and old code).
*/
ErtsLiteralArea** erts_dump_lit_areas;
Uint erts_dump_num_lit_areas;
/* Range 'end' needs to be atomic as we purge module
by setting end=start in active code_ix */
#define RANGE_END(R) ((BeamInstr*)erts_atomic_read_nob(&(R)->end))
static Range* find_range(BeamInstr* pc);
static void lookup_loc(FunctionInfo* fi, const BeamInstr* pc,
BeamCodeHeader*, int idx);
/*
* The following variables keep a sorted list of address ranges for
* each module. It allows us to quickly find a function given an
* instruction pointer.
*/
struct ranges {
Range* modules; /* Sorted lists of module addresses. */
Sint n; /* Number of range entries. */
Sint allocated; /* Number of allocated entries. */
erts_atomic_t mid; /* Cached search start point */
};
static struct ranges r[ERTS_NUM_CODE_IX];
static erts_atomic_t mem_used;
static Range* write_ptr;
#ifdef HARD_DEBUG
static void check_consistency(struct ranges* p)
{
int i;
ASSERT(p->n <= p->allocated);
ASSERT((Uint)(p->mid - p->modules) < p->n ||
(p->mid == p->modules && p->n == 0));
for (i = 0; i < p->n; i++) {
ASSERT(p->modules[i].start <= RANGE_END(&p->modules[i]));
ASSERT(!i || RANGE_END(&p->modules[i-1]) < p->modules[i].start);
}
}
# define CHECK(r) check_consistency(r)
#else
# define CHECK(r)
#endif /* HARD_DEBUG */
static int
rangecompare(Range* a, Range* b)
{
if (a->start < b->start) {
return -1;
} else if (a->start == b->start) {
return 0;
} else {
return 1;
}
}
void
erts_init_ranges(void)
{
Sint i;
erts_atomic_init_nob(&mem_used, 0);
for (i = 0; i < ERTS_NUM_CODE_IX; i++) {
r[i].modules = 0;
r[i].n = 0;
r[i].allocated = 0;
erts_atomic_init_nob(&r[i].mid, 0);
}
erts_dump_num_lit_areas = 8;
erts_dump_lit_areas = (ErtsLiteralArea **)
erts_alloc(ERTS_ALC_T_CRASH_DUMP,
erts_dump_num_lit_areas * sizeof(ErtsLiteralArea*));
}
void
erts_start_staging_ranges(int num_new)
{
ErtsCodeIndex src = erts_active_code_ix();
ErtsCodeIndex dst = erts_staging_code_ix();
Sint need;
if (r[dst].modules) {
erts_atomic_add_nob(&mem_used, -r[dst].allocated);
erts_free(ERTS_ALC_T_MODULE_REFS, r[dst].modules);
}
need = r[dst].allocated = r[src].n + num_new;
erts_atomic_add_nob(&mem_used, need);
write_ptr = erts_alloc(ERTS_ALC_T_MODULE_REFS,
need * sizeof(Range));
r[dst].modules = write_ptr;
}
void
erts_end_staging_ranges(int commit)
{
if (commit) {
Sint i;
ErtsCodeIndex src = erts_active_code_ix();
ErtsCodeIndex dst = erts_staging_code_ix();
Range* mp;
Sint num_inserted;
mp = r[dst].modules;
num_inserted = write_ptr - mp;
for (i = 0; i < r[src].n; i++) {
Range* rp = r[src].modules+i;
if (rp->start < RANGE_END(rp)) {
/* Only insert a module that has not been purged. */
write_ptr->start = rp->start;
erts_atomic_init_nob(&write_ptr->end,
(erts_aint_t)(RANGE_END(rp)));
write_ptr++;
}
}
/*
* There are num_inserted new range entries (unsorted) at the
* beginning of the modules array, followed by the old entries
* (sorted). We must now sort the entire array.
*/
r[dst].n = write_ptr - mp;
if (num_inserted > 1) {
qsort(mp, r[dst].n, sizeof(Range),
(int (*)(const void *, const void *)) rangecompare);
} else if (num_inserted == 1) {
/* Sift the new range into place. This is faster than qsort(). */
Range t = mp[0];
for (i = 0; i < r[dst].n-1 && t.start > mp[i+1].start; i++) {
mp[i] = mp[i+1];
}
mp[i] = t;
}
r[dst].modules = mp;
CHECK(&r[dst]);
erts_atomic_set_nob(&r[dst].mid,
(erts_aint_t) (r[dst].modules +
r[dst].n / 2));
if (r[dst].allocated * 2 > erts_dump_num_lit_areas) {
erts_dump_num_lit_areas *= 2;
erts_dump_lit_areas = (ErtsLiteralArea **)
erts_realloc(ERTS_ALC_T_CRASH_DUMP,
(void *) erts_dump_lit_areas,
erts_dump_num_lit_areas * sizeof(ErtsLiteralArea*));
}
}
}
void
erts_update_ranges(BeamInstr* code, Uint size)
{
ErtsCodeIndex dst = erts_staging_code_ix();
ErtsCodeIndex src = erts_active_code_ix();
if (src == dst) {
ASSERT(!erts_initialized);
/*
* During start-up of system, the indices are the same
* and erts_start_staging_ranges() has not been called.
*/
if (r[dst].modules == NULL) {
Sint need = 128;
erts_atomic_add_nob(&mem_used, need);
r[dst].modules = erts_alloc(ERTS_ALC_T_MODULE_REFS,
need * sizeof(Range));
r[dst].allocated = need;
write_ptr = r[dst].modules;
}
}
ASSERT(r[dst].modules);
write_ptr->start = code;
erts_atomic_init_nob(&(write_ptr->end),
(erts_aint_t)(((byte *)code) + size));
write_ptr++;
}
void
erts_remove_from_ranges(BeamInstr* code)
{
Range* rp = find_range(code);
erts_atomic_set_nob(&rp->end, (erts_aint_t)rp->start);
}
UWord
erts_ranges_sz(void)
{
return erts_atomic_read_nob(&mem_used) * sizeof(Range);
}
/*
* Find a function from the given pc and fill information in
* the FunctionInfo struct. If the full_info is non-zero, fill
* in all available information (including location in the
* source code). If no function is found, the 'current' field
* will be set to NULL.
*/
void
erts_lookup_function_info(FunctionInfo* fi, BeamInstr* pc, int full_info)
{
ErtsCodeInfo** low;
ErtsCodeInfo** high;
ErtsCodeInfo** mid;
Range* rp;
BeamCodeHeader* hdr;
fi->mfa = NULL;
fi->needed = 5;
fi->loc = LINE_INVALID_LOCATION;
rp = find_range(pc);
if (rp == 0) {
return;
}
hdr = (BeamCodeHeader*) rp->start;
low = hdr->functions;
high = low + hdr->num_functions;
while (low < high) {
mid = low + (high-low) / 2;
if (pc < (BeamInstr*)(mid[0])) {
high = mid;
} else if (pc < (BeamInstr*)(mid[1])) {
fi->mfa = &mid[0]->mfa;
if (full_info) {
ErtsCodeInfo** fp = hdr->functions;
int idx = mid - fp;
lookup_loc(fi, pc, hdr, idx);
}
return;
} else {
low = mid + 1;
}
}
}
static Range*
find_range(BeamInstr* pc)
{
ErtsCodeIndex active = erts_active_code_ix();
Range* low = r[active].modules;
Range* high = low + r[active].n;
Range* mid = (Range *) erts_atomic_read_nob(&r[active].mid);
CHECK(&r[active]);
while (low < high) {
if (pc < mid->start) {
high = mid;
} else if (pc >= RANGE_END(mid)) {
low = mid + 1;
} else {
erts_atomic_set_nob(&r[active].mid, (erts_aint_t) mid);
return mid;
}
mid = low + (high-low) / 2;
}
return 0;
}
static void
lookup_loc(FunctionInfo* fi, const BeamInstr* pc,
BeamCodeHeader* code_hdr, int idx)
{
BeamCodeLineTab* lt = code_hdr->line_table;
const BeamInstr** low;
const BeamInstr** high;
const BeamInstr** mid;
if (lt == NULL) {
return;
}
fi->fname_ptr = lt->fname_ptr;
low = lt->func_tab[idx];
high = lt->func_tab[idx+1];
while (high > low) {
mid = low + (high-low) / 2;
if (pc < mid[0]) {
high = mid;
} else if (pc < mid[1]) {
int file;
int index = mid - lt->func_tab[0];
if (lt->loc_size == 2) {
fi->loc = lt->loc_tab.p2[index];
} else {
ASSERT(lt->loc_size == 4);
fi->loc = lt->loc_tab.p4[index];
}
if (fi->loc == LINE_INVALID_LOCATION) {
return;
}
fi->needed += 3+2+3+2;
file = LOC_FILE(fi->loc);
if (file == 0) {
/* Special case: Module name with ".erl" appended */
Atom* mod_atom = atom_tab(atom_val(fi->mfa->module));
fi->needed += 2*(mod_atom->len+4);
} else {
fi->needed += 2*erts_atom_to_string_length((fi->fname_ptr)[file-1]);
}
return;
} else {
low = mid + 1;
}
}
}
