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/***********************************************************************/
/* */
/* Objective Caml */
/* */
/* Xavier Leroy, projet Cristal, INRIA Rocquencourt */
/* */
/* Copyright 2000 Institut National de Recherche en Informatique et */
/* en Automatique. All rights reserved. This file is distributed */
/* under the terms of the GNU Library General Public License. */
/* */
/***********************************************************************/
/* $Id$ */
/* Stack backtrace for uncaught exceptions */
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include "config.h"
#ifdef HAS_UNISTD
#include <unistd.h>
#endif
#include "mlvalues.h"
#include "alloc.h"
#include "io.h"
#include "instruct.h"
#include "intext.h"
#include "exec.h"
#include "fix_code.h"
#include "startup.h"
#include "stacks.h"
#include "sys.h"
#include "backtrace.h"
CAMLexport int backtrace_active = 0;
CAMLexport int backtrace_pos = 0;
CAMLexport code_t * backtrace_buffer = NULL;
#define BACKTRACE_BUFFER_SIZE 1024
/* Location of fields in the Instruct.debug_event record */
enum { EV_POS = 0,
EV_MODULE = 1,
EV_CHAR = 2,
EV_KIND = 3 };
/* Store the return addresses contained in the given stack fragment
into the backtrace array */
void stash_backtrace(code_t pc, value * sp)
{
code_t end_code = start_code + code_size;
if (pc != NULL) pc = pc - 1;
if (backtrace_pos >= BACKTRACE_BUFFER_SIZE) return;
if (backtrace_buffer == NULL) {
backtrace_buffer = malloc(BACKTRACE_BUFFER_SIZE * sizeof(code_t));
if (backtrace_buffer == NULL) return;
}
backtrace_buffer[backtrace_pos++] = pc;
for (/*nothing*/; sp < trapsp; sp++) {
code_t p = (code_t) *sp;
if (p >= start_code && p < end_code) {
if (backtrace_pos >= BACKTRACE_BUFFER_SIZE) break;
backtrace_buffer[backtrace_pos++] = p;
}
}
}
/* Read the debugging info contained in the current bytecode executable.
Return a Caml array of Caml lists of debug_event records in "events",
or Val_false on failure. */
#ifndef O_BINARY
#define O_BINARY 0
#endif
static value read_debug_info(void)
{
CAMLparam0();
CAMLlocal1(events);
char * exec_name;
int fd;
struct exec_trailer trail;
struct channel * chan;
uint32 num_events, orig, i;
value evl, l;
exec_name = caml_main_argv[0];
fd = attempt_open(&exec_name, &trail, 1);
if (fd < 0) CAMLreturn(Val_false);
read_section_descriptors(fd, &trail);
if (seek_optional_section(fd, &trail, "DBUG") == -1) {
close(fd);
CAMLreturn(Val_false);
}
chan = open_descriptor(fd);
num_events = getword(chan);
events = alloc(num_events, 0);
for (i = 0; i < num_events; i++) {
orig = getword(chan);
evl = input_val(chan);
/* Relocate events in event list */
for (l = evl; l != Val_int(0); l = Field(l, 1)) {
value ev = Field(l, 0);
Field(ev, EV_POS) = Val_long(Long_val(Field(ev, EV_POS)) + orig);
}
/* Record event list */
Store_field(events, i, evl);
}
close_channel(chan);
CAMLreturn(events);
}
/* Search the event for the given PC. Return Val_false if not found. */
static value event_for_location(value events, code_t pc)
{
mlsize_t i;
value pos, l, ev;
Assert(pc >= start_code && pc < start_code + code_size);
pos = Val_long((char *) pc - (char *) start_code);
for (i = 0; i < Wosize_val(events); i++) {
for (l = Field(events, i); l != Val_int(0); l = Field(l, 1)) {
ev = Field(l, 0);
if (Field(ev, EV_POS) == pos /* && Is_block(Field(ev, EV_KIND)) */)
return ev;
}
}
return Val_false;
}
/* Print the location corresponding to the given PC */
static void print_location(value events, code_t pc)
{
char * info;
value ev;
if (pc == NULL) {
fprintf(stderr, "Raised from a C function");
return;
}
ev = event_for_location(events, pc);
if (is_instruction(*pc, RAISE)) {
info = "Raised at";
} else if (is_instruction(*pc, RERAISE)) {
/* Ignore compiler-inserted re-raise */
if (ev == Val_false) return;
info = "Re-raised at";
} else {
info = "Called from";
}
if (ev == Val_false) {
fprintf(stderr, "%s unknown location\n", info);
} else {
fprintf(stderr, "%s module %s, character %d\n", info,
String_val(Field(ev, EV_MODULE)),
Int_val(Field(ev, EV_CHAR)));
}
}
/* Print a backtrace */
CAMLexport void print_exception_backtrace(void)
{
value events;
int i, nrepeat;
code_t pc;
events = read_debug_info();
if (events == Val_false) return;
for (i = 0; i < backtrace_pos; i++)
print_location(events, backtrace_buffer[i]);
}
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