qemu/accel/tcg/debuginfo.c
Ilya Leoshkevich 7c10cb38cc accel/tcg: Add debuginfo support
Add libdw-based functions for loading and querying debuginfo. Load
debuginfo from the system and the linux-user loaders.

This is useful for the upcoming perf support, which can then put
human-readable guest symbols instead of raw guest PCs into perfmap and
jitdump files.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Message-Id: <20230112152013.125680-3-iii@linux.ibm.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-01-16 10:14:12 -10:00

97 lines
2.1 KiB
C

/*
* Debug information support.
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include "qemu/osdep.h"
#include "qemu/lockable.h"
#include <elfutils/libdwfl.h>
#include "debuginfo.h"
static QemuMutex lock;
static Dwfl *dwfl;
static const Dwfl_Callbacks dwfl_callbacks = {
.find_elf = NULL,
.find_debuginfo = dwfl_standard_find_debuginfo,
.section_address = NULL,
.debuginfo_path = NULL,
};
__attribute__((constructor))
static void debuginfo_init(void)
{
qemu_mutex_init(&lock);
}
void debuginfo_report_elf(const char *name, int fd, uint64_t bias)
{
QEMU_LOCK_GUARD(&lock);
if (dwfl) {
dwfl_report_begin_add(dwfl);
} else {
dwfl = dwfl_begin(&dwfl_callbacks);
}
if (dwfl) {
dwfl_report_elf(dwfl, name, name, fd, bias, true);
dwfl_report_end(dwfl, NULL, NULL);
}
}
void debuginfo_lock(void)
{
qemu_mutex_lock(&lock);
}
void debuginfo_query(struct debuginfo_query *q, size_t n)
{
const char *symbol, *file;
Dwfl_Module *dwfl_module;
Dwfl_Line *dwfl_line;
GElf_Off dwfl_offset;
GElf_Sym dwfl_sym;
size_t i;
int line;
if (!dwfl) {
return;
}
for (i = 0; i < n; i++) {
dwfl_module = dwfl_addrmodule(dwfl, q[i].address);
if (!dwfl_module) {
continue;
}
if (q[i].flags & DEBUGINFO_SYMBOL) {
symbol = dwfl_module_addrinfo(dwfl_module, q[i].address,
&dwfl_offset, &dwfl_sym,
NULL, NULL, NULL);
if (symbol) {
q[i].symbol = symbol;
q[i].offset = dwfl_offset;
}
}
if (q[i].flags & DEBUGINFO_LINE) {
dwfl_line = dwfl_module_getsrc(dwfl_module, q[i].address);
if (dwfl_line) {
file = dwfl_lineinfo(dwfl_line, NULL, &line, 0, NULL, NULL);
if (file) {
q[i].file = file;
q[i].line = line;
}
}
}
}
}
void debuginfo_unlock(void)
{
qemu_mutex_unlock(&lock);
}