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tinycc/tccrun.c
Thomas Preud'homme 6ed6a36a51 Flush caches before -running program 
On some architectures, ARM for instance, the data and instruction caches
are not coherent with each other. This is a problem for the -run feature
since instructions are written in memory, and are thus written in the
data cache first and then later flushed to the main memory. If the
instructions are executed before they are pushed out of the cache, then
the processor will fetch the old content from the memory and not the
newly generated code. The solution is to flush from the data cache all
the data in the memory region containing the instructions and to
invalidate the same region in the instruction cache.
2013-03-18 10:08:39 +01:00

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/*
* TCC - Tiny C Compiler - Support for -run switch
*
* Copyright (c) 2001-2004 Fabrice Bellard
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "tcc.h"
/* only native compiler supports -run */
#ifdef TCC_IS_NATIVE
#ifdef CONFIG_TCC_BACKTRACE
ST_DATA int rt_num_callers = 6;
ST_DATA const char **rt_bound_error_msg;
ST_DATA void *rt_prog_main;
#endif
#ifdef _WIN32
#define ucontext_t CONTEXT
#endif
static void set_pages_executable(void *ptr, unsigned long length);
static void set_exception_handler(void);
static int rt_get_caller_pc(addr_t *paddr, ucontext_t *uc, int level);
static void rt_error(ucontext_t *uc, const char *fmt, ...);
static int tcc_relocate_ex(TCCState *s1, void *ptr);
#ifdef _WIN64
static void win64_add_function_table(TCCState *s1);
#endif
/* ------------------------------------------------------------- */
/* Do all relocations (needed before using tcc_get_symbol())
Returns -1 on error. */
LIBTCCAPI int tcc_relocate(TCCState *s1, void *ptr)
{
int ret;
if (TCC_RELOCATE_AUTO != ptr)
return tcc_relocate_ex(s1, ptr);
ret = tcc_relocate_ex(s1, NULL);
if (ret < 0)
return ret;
#ifdef HAVE_SELINUX
{ /* Use mmap instead of malloc for Selinux. Ref:
http://www.gnu.org/s/libc/manual/html_node/File-Size.html */
char tmpfname[] = "/tmp/.tccrunXXXXXX";
int fd = mkstemp (tmpfname);
s1->mem_size = ret;
unlink (tmpfname);
ftruncate (fd, s1->mem_size);
s1->write_mem = mmap (NULL, ret, PROT_READ|PROT_WRITE,
MAP_SHARED, fd, 0);
if (s1->write_mem == MAP_FAILED)
tcc_error("/tmp not writeable");
s1->runtime_mem = mmap (NULL, ret, PROT_READ|PROT_EXEC,
MAP_SHARED, fd, 0);
if (s1->runtime_mem == MAP_FAILED)
tcc_error("/tmp not executable");
ret = tcc_relocate_ex(s1, s1->write_mem);
}
#else
s1->runtime_mem = tcc_malloc(ret);
ret = tcc_relocate_ex(s1, s1->runtime_mem);
#endif
return ret;
}
/* launch the compiled program with the given arguments */
LIBTCCAPI int tcc_run(TCCState *s1, int argc, char **argv)
{
int (*prog_main)(int, char **);
int ret;
if (tcc_relocate(s1, TCC_RELOCATE_AUTO) < 0)
return -1;
prog_main = tcc_get_symbol_err(s1, "main");
#ifdef CONFIG_TCC_BACKTRACE
if (s1->do_debug) {
set_exception_handler();
rt_prog_main = prog_main;
}
#endif
#ifdef CONFIG_TCC_BCHECK
if (s1->do_bounds_check) {
void (*bound_init)(void);
void (*bound_exit)(void);
/* set error function */
rt_bound_error_msg = tcc_get_symbol_err(s1, "__bound_error_msg");
/* XXX: use .init section so that it also work in binary ? */
bound_init = tcc_get_symbol_err(s1, "__bound_init");
bound_exit = tcc_get_symbol_err(s1, "__bound_exit");
bound_init();
ret = (*prog_main)(argc, argv);
bound_exit();
} else
#endif
ret = (*prog_main)(argc, argv);
return ret;
}
/* relocate code. Return -1 on error, required size if ptr is NULL,
otherwise copy code into buffer passed by the caller */
static int tcc_relocate_ex(TCCState *s1, void *ptr)
{
Section *s;
unsigned long offset, length;
addr_t mem;
int i;
if (NULL == ptr) {
s1->nb_errors = 0;
#ifdef TCC_TARGET_PE
pe_output_file(s1, NULL);
#else
tcc_add_runtime(s1);
relocate_common_syms();
tcc_add_linker_symbols(s1);
build_got_entries(s1);
#endif
if (s1->nb_errors)
return -1;
}
offset = 0, mem = (addr_t)ptr;
for(i = 1; i < s1->nb_sections; i++) {
s = s1->sections[i];
if (0 == (s->sh_flags & SHF_ALLOC))
continue;
length = s->data_offset;
s->sh_addr = mem ? (mem + offset + 15) & ~15 : 0;
offset = (offset + length + 15) & ~15;
}
offset += 16;
/* relocate symbols */
relocate_syms(s1, 1);
if (s1->nb_errors)
return -1;
#ifdef TCC_HAS_RUNTIME_PLTGOT
s1->runtime_plt_and_got_offset = 0;
s1->runtime_plt_and_got = (char *)(mem + offset);
/* double the size of the buffer for got and plt entries
XXX: calculate exact size for them? */
offset *= 2;
#endif
if (0 == mem)
return offset;
/* relocate each section */
for(i = 1; i < s1->nb_sections; i++) {
s = s1->sections[i];
if (s->reloc)
relocate_section(s1, s);
}
for(i = 1; i < s1->nb_sections; i++) {
s = s1->sections[i];
if (0 == (s->sh_flags & SHF_ALLOC))
continue;
length = s->data_offset;
// printf("%-12s %08x %04x\n", s->name, s->sh_addr, length);
ptr = (void*)s->sh_addr;
if (NULL == s->data || s->sh_type == SHT_NOBITS)
memset(ptr, 0, length);
else
memcpy(ptr, s->data, length);
/* mark executable sections as executable in memory */
if (s->sh_flags & SHF_EXECINSTR)
set_pages_executable(ptr, length);
}
#ifdef TCC_HAS_RUNTIME_PLTGOT
set_pages_executable(s1->runtime_plt_and_got,
s1->runtime_plt_and_got_offset);
#endif
#ifdef _WIN64
win64_add_function_table(s1);
#endif
return 0;
}
/* ------------------------------------------------------------- */
/* allow to run code in memory */
static void set_pages_executable(void *ptr, unsigned long length)
{
#ifdef _WIN32
unsigned long old_protect;
VirtualProtect(ptr, length, PAGE_EXECUTE_READWRITE, &old_protect);
#else
#ifndef PAGESIZE
# define PAGESIZE 4096
#endif
addr_t start, end;
start = (addr_t)ptr & ~(PAGESIZE - 1);
end = (addr_t)ptr + length;
end = (end + PAGESIZE - 1) & ~(PAGESIZE - 1);
mprotect((void *)start, end - start, PROT_READ | PROT_WRITE | PROT_EXEC);
__clear_cache(ptr, prog_main + length);
#endif
}
/* ------------------------------------------------------------- */
#ifdef CONFIG_TCC_BACKTRACE
ST_FUNC void tcc_set_num_callers(int n)
{
rt_num_callers = n;
}
/* print the position in the source file of PC value 'pc' by reading
the stabs debug information */
static addr_t rt_printline(addr_t wanted_pc, const char *msg)
{
char func_name[128], last_func_name[128];
addr_t func_addr, last_pc, pc;
const char *incl_files[INCLUDE_STACK_SIZE];
int incl_index, len, last_line_num, i;
const char *str, *p;
Stab_Sym *stab_sym = NULL, *stab_sym_end, *sym;
int stab_len = 0;
char *stab_str = NULL;
if (stab_section) {
stab_len = stab_section->data_offset;
stab_sym = (Stab_Sym *)stab_section->data;
stab_str = stabstr_section->data;
}
func_name[0] = '\0';
func_addr = 0;
incl_index = 0;
last_func_name[0] = '\0';
last_pc = (addr_t)-1;
last_line_num = 1;
if (!stab_sym)
goto no_stabs;
stab_sym_end = (Stab_Sym*)((char*)stab_sym + stab_len);
for (sym = stab_sym + 1; sym < stab_sym_end; ++sym) {
switch(sym->n_type) {
/* function start or end */
case N_FUN:
if (sym->n_strx == 0) {
/* we test if between last line and end of function */
pc = sym->n_value + func_addr;
if (wanted_pc >= last_pc && wanted_pc < pc)
goto found;
func_name[0] = '\0';
func_addr = 0;
} else {
str = stab_str + sym->n_strx;
p = strchr(str, ':');
if (!p) {
pstrcpy(func_name, sizeof(func_name), str);
} else {
len = p - str;
if (len > sizeof(func_name) - 1)
len = sizeof(func_name) - 1;
memcpy(func_name, str, len);
func_name[len] = '\0';
}
func_addr = sym->n_value;
}
break;
/* line number info */
case N_SLINE:
pc = sym->n_value + func_addr;
if (wanted_pc >= last_pc && wanted_pc < pc)
goto found;
last_pc = pc;
last_line_num = sym->n_desc;
/* XXX: slow! */
strcpy(last_func_name, func_name);
break;
/* include files */
case N_BINCL:
str = stab_str + sym->n_strx;
add_incl:
if (incl_index < INCLUDE_STACK_SIZE) {
incl_files[incl_index++] = str;
}
break;
case N_EINCL:
if (incl_index > 1)
incl_index--;
break;
case N_SO:
if (sym->n_strx == 0) {
incl_index = 0; /* end of translation unit */
} else {
str = stab_str + sym->n_strx;
/* do not add path */
len = strlen(str);
if (len > 0 && str[len - 1] != '/')
goto add_incl;
}
break;
}
}
no_stabs:
/* second pass: we try symtab symbols (no line number info) */
incl_index = 0;
if (symtab_section)
{
ElfW(Sym) *sym, *sym_end;
int type;
sym_end = (ElfW(Sym) *)(symtab_section->data + symtab_section->data_offset);
for(sym = (ElfW(Sym) *)symtab_section->data + 1;
sym < sym_end;
sym++) {
type = ELFW(ST_TYPE)(sym->st_info);
if (type == STT_FUNC || type == STT_GNU_IFUNC) {
if (wanted_pc >= sym->st_value &&
wanted_pc < sym->st_value + sym->st_size) {
pstrcpy(last_func_name, sizeof(last_func_name),
strtab_section->data + sym->st_name);
func_addr = sym->st_value;
goto found;
}
}
}
}
/* did not find any info: */
fprintf(stderr, "%s %p ???\n", msg, (void*)wanted_pc);
fflush(stderr);
return 0;
found:
i = incl_index;
if (i > 0)
fprintf(stderr, "%s:%d: ", incl_files[--i], last_line_num);
fprintf(stderr, "%s %p", msg, (void*)wanted_pc);
if (last_func_name[0] != '\0')
fprintf(stderr, " %s()", last_func_name);
if (--i >= 0) {
fprintf(stderr, " (included from ");
for (;;) {
fprintf(stderr, "%s", incl_files[i]);
if (--i < 0)
break;
fprintf(stderr, ", ");
}
fprintf(stderr, ")");
}
fprintf(stderr, "\n");
fflush(stderr);
return func_addr;
}
/* emit a run time error at position 'pc' */
static void rt_error(ucontext_t *uc, const char *fmt, ...)
{
va_list ap;
addr_t pc;
int i;
fprintf(stderr, "Runtime error: ");
va_start(ap, fmt);
vfprintf(stderr, fmt, ap);
va_end(ap);
fprintf(stderr, "\n");
for(i=0;i<rt_num_callers;i++) {
if (rt_get_caller_pc(&pc, uc, i) < 0)
break;
pc = rt_printline(pc, i ? "by" : "at");
if (pc == (addr_t)rt_prog_main && pc)
break;
}
}
/* ------------------------------------------------------------- */
#ifndef _WIN32
/* signal handler for fatal errors */
static void sig_error(int signum, siginfo_t *siginf, void *puc)
{
ucontext_t *uc = puc;
switch(signum) {
case SIGFPE:
switch(siginf->si_code) {
case FPE_INTDIV:
case FPE_FLTDIV:
rt_error(uc, "division by zero");
break;
default:
rt_error(uc, "floating point exception");
break;
}
break;
case SIGBUS:
case SIGSEGV:
if (rt_bound_error_msg && *rt_bound_error_msg)
rt_error(uc, *rt_bound_error_msg);
else
rt_error(uc, "dereferencing invalid pointer");
break;
case SIGILL:
rt_error(uc, "illegal instruction");
break;
case SIGABRT:
rt_error(uc, "abort() called");
break;
default:
rt_error(uc, "caught signal %d", signum);
break;
}
exit(255);
}
#ifndef SA_SIGINFO
# define SA_SIGINFO 0x00000004u
#endif
/* Generate a stack backtrace when a CPU exception occurs. */
static void set_exception_handler(void)
{
struct sigaction sigact;
/* install TCC signal handlers to print debug info on fatal
runtime errors */
sigact.sa_flags = SA_SIGINFO | SA_RESETHAND;
sigact.sa_sigaction = sig_error;
sigemptyset(&sigact.sa_mask);
sigaction(SIGFPE, &sigact, NULL);
sigaction(SIGILL, &sigact, NULL);
sigaction(SIGSEGV, &sigact, NULL);
sigaction(SIGBUS, &sigact, NULL);
sigaction(SIGABRT, &sigact, NULL);
}
/* ------------------------------------------------------------- */
#ifdef __i386__
/* fix for glibc 2.1 */
#ifndef REG_EIP
#define REG_EIP EIP
#define REG_EBP EBP
#endif
/* return the PC at frame level 'level'. Return negative if not found */
static int rt_get_caller_pc(addr_t *paddr, ucontext_t *uc, int level)
{
addr_t fp;
int i;
if (level == 0) {
#if defined(__APPLE__)
*paddr = uc->uc_mcontext->__ss.__eip;
#elif defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
*paddr = uc->uc_mcontext.mc_eip;
#elif defined(__dietlibc__)
*paddr = uc->uc_mcontext.eip;
#else
*paddr = uc->uc_mcontext.gregs[REG_EIP];
#endif
return 0;
} else {
#if defined(__APPLE__)
fp = uc->uc_mcontext->__ss.__ebp;
#elif defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
fp = uc->uc_mcontext.mc_ebp;
#elif defined(__dietlibc__)
fp = uc->uc_mcontext.ebp;
#else
fp = uc->uc_mcontext.gregs[REG_EBP];
#endif
for(i=1;i<level;i++) {
/* XXX: check address validity with program info */
if (fp <= 0x1000 || fp >= 0xc0000000)
return -1;
fp = ((addr_t *)fp)[0];
}
*paddr = ((addr_t *)fp)[1];
return 0;
}
}
/* ------------------------------------------------------------- */
#elif defined(__x86_64__)
/* return the PC at frame level 'level'. Return negative if not found */
static int rt_get_caller_pc(addr_t *paddr, ucontext_t *uc, int level)
{
addr_t fp;
int i;
if (level == 0) {
/* XXX: only support linux */
#if defined(__APPLE__)
*paddr = uc->uc_mcontext->__ss.__rip;
#elif defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
*paddr = uc->uc_mcontext.mc_rip;
#else
*paddr = uc->uc_mcontext.gregs[REG_RIP];
#endif
return 0;
} else {
#if defined(__APPLE__)
fp = uc->uc_mcontext->__ss.__rbp;
#elif defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
fp = uc->uc_mcontext.mc_rbp;
#else
fp = uc->uc_mcontext.gregs[REG_RBP];
#endif
for(i=1;i<level;i++) {
/* XXX: check address validity with program info */
if (fp <= 0x1000)
return -1;
fp = ((addr_t *)fp)[0];
}
*paddr = ((addr_t *)fp)[1];
return 0;
}
}
/* ------------------------------------------------------------- */
#elif defined(__arm__)
/* return the PC at frame level 'level'. Return negative if not found */
static int rt_get_caller_pc(addr_t *paddr, ucontext_t *uc, int level)
{
addr_t fp, sp;
int i;
if (level == 0) {
/* XXX: only supports linux */
#if defined(__linux__)
*paddr = uc->uc_mcontext.arm_pc;
#else
return -1;
#endif
return 0;
} else {
#if defined(__linux__)
fp = uc->uc_mcontext.arm_fp;
sp = uc->uc_mcontext.arm_sp;
if (sp < 0x1000)
sp = 0x1000;
#else
return -1;
#endif
/* XXX: specific to tinycc stack frames */
if (fp < sp + 12 || fp & 3)
return -1;
for(i = 1; i < level; i++) {
sp = ((addr_t *)fp)[-2];
if (sp < fp || sp - fp > 16 || sp & 3)
return -1;
fp = ((addr_t *)fp)[-3];
if (fp <= sp || fp - sp < 12 || fp & 3)
return -1;
}
/* XXX: check address validity with program info */
*paddr = ((addr_t *)fp)[-1];
return 0;
}
}
/* ------------------------------------------------------------- */
#else
#warning add arch specific rt_get_caller_pc()
static int rt_get_caller_pc(addr_t *paddr, ucontext_t *uc, int level)
{
return -1;
}
#endif /* !__i386__ */
/* ------------------------------------------------------------- */
#else /* WIN32 */
static long __stdcall cpu_exception_handler(EXCEPTION_POINTERS *ex_info)
{
EXCEPTION_RECORD *er = ex_info->ExceptionRecord;
CONTEXT *uc = ex_info->ContextRecord;
switch (er->ExceptionCode) {
case EXCEPTION_ACCESS_VIOLATION:
if (rt_bound_error_msg && *rt_bound_error_msg)
rt_error(uc, *rt_bound_error_msg);
else
rt_error(uc, "access violation");
break;
case EXCEPTION_STACK_OVERFLOW:
rt_error(uc, "stack overflow");
break;
case EXCEPTION_INT_DIVIDE_BY_ZERO:
rt_error(uc, "division by zero");
break;
default:
rt_error(uc, "exception caught");
break;
}
return EXCEPTION_EXECUTE_HANDLER;
}
/* Generate a stack backtrace when a CPU exception occurs. */
static void set_exception_handler(void)
{
SetUnhandledExceptionFilter(cpu_exception_handler);
}
#ifdef _WIN64
static void win64_add_function_table(TCCState *s1)
{
RtlAddFunctionTable(
(RUNTIME_FUNCTION*)s1->uw_pdata->sh_addr,
s1->uw_pdata->data_offset / sizeof (RUNTIME_FUNCTION),
text_section->sh_addr
);
}
#endif
/* return the PC at frame level 'level'. Return non zero if not found */
static int rt_get_caller_pc(addr_t *paddr, CONTEXT *uc, int level)
{
addr_t fp, pc;
int i;
#ifdef _WIN64
pc = uc->Rip;
fp = uc->Rbp;
#else
pc = uc->Eip;
fp = uc->Ebp;
#endif
if (level > 0) {
for(i=1;i<level;i++) {
/* XXX: check address validity with program info */
if (fp <= 0x1000 || fp >= 0xc0000000)
return -1;
fp = ((addr_t*)fp)[0];
}
pc = ((addr_t*)fp)[1];
}
*paddr = pc;
return 0;
}
#endif /* _WIN32 */
#endif /* CONFIG_TCC_BACKTRACE */
/* ------------------------------------------------------------- */
#ifdef CONFIG_TCC_STATIC
/* dummy function for profiling */
ST_FUNC void *dlopen(const char *filename, int flag)
{
return NULL;
}
ST_FUNC void dlclose(void *p)
{
}
ST_FUNC const char *dlerror(void)
{
return "error";
}
typedef struct TCCSyms {
char *str;
void *ptr;
} TCCSyms;
/* add the symbol you want here if no dynamic linking is done */
static TCCSyms tcc_syms[] = {
#if !defined(CONFIG_TCCBOOT)
#define TCCSYM(a) { #a, &a, },
TCCSYM(printf)
TCCSYM(fprintf)
TCCSYM(fopen)
TCCSYM(fclose)
#undef TCCSYM
#endif
{ NULL, NULL },
};
ST_FUNC void *resolve_sym(TCCState *s1, const char *symbol)
{
TCCSyms *p;
p = tcc_syms;
while (p->str != NULL) {
if (!strcmp(p->str, symbol))
return p->ptr;
p++;
}
return NULL;
}
#elif !defined(_WIN32)
ST_FUNC void *resolve_sym(TCCState *s1, const char *sym)
{
return dlsym(RTLD_DEFAULT, sym);
}
#endif /* CONFIG_TCC_STATIC */
#endif /* TCC_IS_NATIVE */
/* ------------------------------------------------------------- */
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