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tccasm.c
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tccasm.c
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/*
* GAS like assembler for TCC
*
* 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
*/
static int asm_get_local_label_name(TCCState *s1, unsigned int n)
{
char buf[64];
TokenSym *ts;
snprintf(buf, sizeof(buf), "L..%u", n);
ts = tok_alloc(buf, strlen(buf));
return ts->tok;
}
static void asm_expr(TCCState *s1, ExprValue *pe);
/* We do not use the C expression parser to handle symbols. Maybe the
C expression parser could be tweaked to do so. */
static void asm_expr_unary(TCCState *s1, ExprValue *pe)
{
Sym *sym;
int op, n, label;
const char *p;
switch(tok) {
case TOK_PPNUM:
p = tokc.cstr->data;
n = strtoul(p, (char **)&p, 0);
if (*p == 'b' || *p == 'f') {
/* backward or forward label */
label = asm_get_local_label_name(s1, n);
sym = label_find(label);
if (*p == 'b') {
/* backward : find the last corresponding defined label */
if (sym && sym->r == 0)
sym = sym->prev_tok;
if (!sym)
error("local label '%d' not found backward", n);
} else {
/* forward */
if (!sym || sym->r) {
/* if the last label is defined, then define a new one */
sym = label_push(&s1->asm_labels, label, 0);
sym->type.t = VT_STATIC | VT_VOID;
}
}
pe->v = 0;
pe->sym = sym;
} else if (*p == '\0') {
pe->v = n;
pe->sym = NULL;
} else {
error("invalid number syntax");
}
next();
break;
case '+':
next();
asm_expr_unary(s1, pe);
break;
case '-':
case '~':
op = tok;
next();
asm_expr_unary(s1, pe);
if (pe->sym)
error("invalid operation with label");
if (op == '-')
pe->v = -pe->v;
else
pe->v = ~pe->v;
break;
case TOK_CCHAR:
case TOK_LCHAR:
pe->v = tokc.i;
pe->sym = NULL;
next();
break;
case '(':
next();
asm_expr(s1, pe);
skip(')');
break;
default:
if (tok >= TOK_IDENT) {
/* label case : if the label was not found, add one */
sym = label_find(tok);
if (!sym) {
sym = label_push(&s1->asm_labels, tok, 0);
/* NOTE: by default, the symbol is global */
sym->type.t = VT_VOID;
}
if (sym->r == SHN_ABS) {
/* if absolute symbol, no need to put a symbol value */
pe->v = (long)sym->next;
pe->sym = NULL;
} else {
pe->v = 0;
pe->sym = sym;
}
next();
} else {
error("bad expression syntax [%s]", get_tok_str(tok, &tokc));
}
break;
}
}
static void asm_expr_prod(TCCState *s1, ExprValue *pe)
{
int op;
ExprValue e2;
asm_expr_unary(s1, pe);
for(;;) {
op = tok;
if (op != '*' && op != '/' && op != '%' &&
op != TOK_SHL && op != TOK_SAR)
break;
next();
asm_expr_unary(s1, &e2);
if (pe->sym || e2.sym)
error("invalid operation with label");
switch(op) {
case '*':
pe->v *= e2.v;
break;
case '/':
if (e2.v == 0) {
div_error:
error("division by zero");
}
pe->v /= e2.v;
break;
case '%':
if (e2.v == 0)
goto div_error;
pe->v %= e2.v;
break;
case TOK_SHL:
pe->v <<= e2.v;
break;
default:
case TOK_SAR:
pe->v >>= e2.v;
break;
}
}
}
static void asm_expr_logic(TCCState *s1, ExprValue *pe)
{
int op;
ExprValue e2;
asm_expr_prod(s1, pe);
for(;;) {
op = tok;
if (op != '&' && op != '|' && op != '^')
break;
next();
asm_expr_prod(s1, &e2);
if (pe->sym || e2.sym)
error("invalid operation with label");
switch(op) {
case '&':
pe->v &= e2.v;
break;
case '|':
pe->v |= e2.v;
break;
default:
case '^':
pe->v ^= e2.v;
break;
}
}
}
static inline void asm_expr_sum(TCCState *s1, ExprValue *pe)
{
int op;
ExprValue e2;
asm_expr_logic(s1, pe);
for(;;) {
op = tok;
if (op != '+' && op != '-')
break;
next();
asm_expr_logic(s1, &e2);
if (op == '+') {
if (pe->sym != NULL && e2.sym != NULL)
goto cannot_relocate;
pe->v += e2.v;
if (pe->sym == NULL && e2.sym != NULL)
pe->sym = e2.sym;
} else {
pe->v -= e2.v;
/* NOTE: we are less powerful than gas in that case
because we store only one symbol in the expression */
if (!pe->sym && !e2.sym) {
/* OK */
} else if (pe->sym && !e2.sym) {
/* OK */
} else if (pe->sym && e2.sym) {
if (pe->sym == e2.sym) {
/* OK */
} else if (pe->sym->r == e2.sym->r && pe->sym->r != 0) {
/* we also accept defined symbols in the same section */
pe->v += (long)pe->sym->next - (long)e2.sym->next;
} else {
goto cannot_relocate;
}
pe->sym = NULL; /* same symbols can be substracted to NULL */
} else {
cannot_relocate:
error("invalid operation with label");
}
}
}
}
static void asm_expr(TCCState *s1, ExprValue *pe)
{
asm_expr_sum(s1, pe);
}
static int asm_int_expr(TCCState *s1)
{
ExprValue e;
asm_expr(s1, &e);
if (e.sym)
expect("constant");
return e.v;
}
/* NOTE: the same name space as C labels is used to avoid using too
much memory when storing labels in TokenStrings */
static void asm_new_label1(TCCState *s1, int label, int is_local,
int sh_num, int value)
{
Sym *sym;
sym = label_find(label);
if (sym) {
if (sym->r) {
/* the label is already defined */
if (!is_local) {
error("assembler label '%s' already defined",
get_tok_str(label, NULL));
} else {
/* redefinition of local labels is possible */
goto new_label;
}
}
} else {
new_label:
sym = label_push(&s1->asm_labels, label, 0);
sym->type.t = VT_STATIC | VT_VOID;
}
sym->r = sh_num;
sym->next = (void *)value;
}
static void asm_new_label(TCCState *s1, int label, int is_local)
{
asm_new_label1(s1, label, is_local, cur_text_section->sh_num, ind);
}
static void asm_free_labels(TCCState *st)
{
Sym *s, *s1;
Section *sec;
for(s = st->asm_labels; s != NULL; s = s1) {
s1 = s->prev;
/* define symbol value in object file */
if (s->r) {
if (s->r == SHN_ABS)
sec = SECTION_ABS;
else
sec = st->sections[s->r];
put_extern_sym2(s, sec, (long)s->next, 0, 0);
}
/* remove label */
table_ident[s->v - TOK_IDENT]->sym_label = NULL;
sym_free(s);
}
st->asm_labels = NULL;
}
static void use_section1(TCCState *s1, Section *sec)
{
cur_text_section->data_offset = ind;
cur_text_section = sec;
ind = cur_text_section->data_offset;
}
static void use_section(TCCState *s1, const char *name)
{
Section *sec;
sec = find_section(s1, name);
use_section1(s1, sec);
}
static void asm_parse_directive(TCCState *s1)
{
int n, offset, v, size, tok1;
Section *sec;
uint8_t *ptr;
/* assembler directive */
next();
sec = cur_text_section;
switch(tok) {
case TOK_ASM_align:
case TOK_ASM_skip:
case TOK_ASM_space:
tok1 = tok;
next();
n = asm_int_expr(s1);
if (tok1 == TOK_ASM_align) {
if (n < 0 || (n & (n-1)) != 0)
error("alignment must be a positive power of two");
offset = (ind + n - 1) & -n;
size = offset - ind;
/* the section must have a compatible alignment */
if (sec->sh_addralign < n)
sec->sh_addralign = n;
} else {
size = n;
}
v = 0;
if (tok == ',') {
next();
v = asm_int_expr(s1);
}
zero_pad:
if (sec->sh_type != SHT_NOBITS) {
sec->data_offset = ind;
ptr = section_ptr_add(sec, size);
memset(ptr, v, size);
}
ind += size;
break;
case TOK_ASM_quad:
next();
for(;;) {
uint64_t vl;
const char *p;
p = tokc.cstr->data;
if (tok != TOK_PPNUM) {
error_constant:
error("64 bit constant");
}
vl = strtoll(p, (char **)&p, 0);
if (*p != '\0')
goto error_constant;
next();
if (sec->sh_type != SHT_NOBITS) {
/* XXX: endianness */
gen_le32(vl);
gen_le32(vl >> 32);
} else {
ind += 8;
}
if (tok != ',')
break;
next();
}
break;
case TOK_ASM_byte:
size = 1;
goto asm_data;
case TOK_ASM_word:
case TOK_SHORT:
size = 2;
goto asm_data;
case TOK_LONG:
case TOK_INT:
size = 4;
asm_data:
next();
for(;;) {
ExprValue e;
asm_expr(s1, &e);
if (sec->sh_type != SHT_NOBITS) {
if (size == 4) {
gen_expr32(&e);
} else {
if (e.sym)
expect("constant");
if (size == 1)
g(e.v);
else
gen_le16(e.v);
}
} else {
ind += size;
}
if (tok != ',')
break;
next();
}
break;
case TOK_ASM_fill:
{
int repeat, size, val, i, j;
uint8_t repeat_buf[8];
next();
repeat = asm_int_expr(s1);
if (repeat < 0) {
error("repeat < 0; .fill ignored");
break;
}
size = 1;
val = 0;
if (tok == ',') {
next();
size = asm_int_expr(s1);
if (size < 0) {
error("size < 0; .fill ignored");
break;
}
if (size > 8)
size = 8;
if (tok == ',') {
next();
val = asm_int_expr(s1);
}
}
/* XXX: endianness */
repeat_buf[0] = val;
repeat_buf[1] = val >> 8;
repeat_buf[2] = val >> 16;
repeat_buf[3] = val >> 24;
repeat_buf[4] = 0;
repeat_buf[5] = 0;
repeat_buf[6] = 0;
repeat_buf[7] = 0;
for(i = 0; i < repeat; i++) {
for(j = 0; j < size; j++) {
g(repeat_buf[j]);
}
}
}
break;
case TOK_ASM_org:
{
unsigned long n;
next();
/* XXX: handle section symbols too */
n = asm_int_expr(s1);
if (n < ind)
error("attempt to .org backwards");
v = 0;
size = n - ind;
goto zero_pad;
}
break;
case TOK_ASM_globl:
case TOK_ASM_global:
{
Sym *sym;
next();
sym = label_find(tok);
if (!sym) {
sym = label_push(&s1->asm_labels, tok, 0);
sym->type.t = VT_VOID;
}
sym->type.t &= ~VT_STATIC;
next();
}
break;
case TOK_ASM_string:
case TOK_ASM_ascii:
case TOK_ASM_asciz:
{
const uint8_t *p;
int i, size, t;
t = tok;
next();
for(;;) {
if (tok != TOK_STR)
expect("string constant");
p = tokc.cstr->data;
size = tokc.cstr->size;
if (t == TOK_ASM_ascii && size > 0)
size--;
for(i = 0; i < size; i++)
g(p[i]);
next();
if (tok == ',') {
next();
} else if (tok != TOK_STR) {
break;
}
}
}
break;
case TOK_ASM_text:
case TOK_ASM_data:
case TOK_ASM_bss:
{
char sname[64];
tok1 = tok;
n = 0;
next();
if (tok != ';' && tok != TOK_LINEFEED) {
n = asm_int_expr(s1);
next();
}
sprintf(sname, (n?".%s%d":".%s"), get_tok_str(tok1, NULL), n);
use_section(s1, sname);
}
break;
case TOK_SECTION1:
{
char sname[256];
/* XXX: support more options */
next();
sname[0] = '\0';
while (tok != ';' && tok != TOK_LINEFEED && tok != ',') {
if (tok == TOK_STR)
pstrcat(sname, sizeof(sname), tokc.cstr->data);
else
pstrcat(sname, sizeof(sname), get_tok_str(tok, NULL));
next();
}
if (tok == ',') {
/* skip section options */
next();
if (tok != TOK_STR)
expect("string constant");
next();
}
last_text_section = cur_text_section;
use_section(s1, sname);
}
break;
case TOK_ASM_previous:
{
Section *sec;
next();
if (!last_text_section)
error("no previous section referenced");
sec = cur_text_section;
use_section1(s1, last_text_section);
last_text_section = sec;
}
break;
default:
error("unknown assembler directive '.%s'", get_tok_str(tok, NULL));
break;
}
}
/* assemble a file */
static int tcc_assemble_internal(TCCState *s1, int do_preprocess)
{
int opcode;
#if 0
/* print stats about opcodes */
{
const ASMInstr *pa;
int freq[4];
int op_vals[500];
int nb_op_vals, i, j;
nb_op_vals = 0;
memset(freq, 0, sizeof(freq));
for(pa = asm_instrs; pa->sym != 0; pa++) {
freq[pa->nb_ops]++;
for(i=0;i<pa->nb_ops;i++) {
for(j=0;j<nb_op_vals;j++) {
if (pa->op_type[i] == op_vals[j])
goto found;
}
op_vals[nb_op_vals++] = pa->op_type[i];
found: ;
}
}
for(i=0;i<nb_op_vals;i++) {
int v = op_vals[i];
if ((v & (v - 1)) != 0)
printf("%3d: %08x\n", i, v);
}
printf("size=%d nb=%d f0=%d f1=%d f2=%d f3=%d\n",
sizeof(asm_instrs), sizeof(asm_instrs) / sizeof(ASMInstr),
freq[0], freq[1], freq[2], freq[3]);
}
#endif
/* XXX: undefine C labels */
ch = file->buf_ptr[0];
tok_flags = TOK_FLAG_BOL | TOK_FLAG_BOF;
parse_flags = PARSE_FLAG_ASM_COMMENTS;
if (do_preprocess)
parse_flags |= PARSE_FLAG_PREPROCESS;
next();
for(;;) {
if (tok == TOK_EOF)
break;
parse_flags |= PARSE_FLAG_LINEFEED; /* XXX: suppress that hack */
redo:
if (tok == '#') {
/* horrible gas comment */
while (tok != TOK_LINEFEED)
next();
} else if (tok == '.') {
asm_parse_directive(s1);
} else if (tok == TOK_PPNUM) {
const char *p;
int n;
p = tokc.cstr->data;
n = strtoul(p, (char **)&p, 10);
if (*p != '\0')
expect("':'");
/* new local label */
asm_new_label(s1, asm_get_local_label_name(s1, n), 1);
next();
skip(':');
goto redo;
} else if (tok >= TOK_IDENT) {
/* instruction or label */
opcode = tok;
next();
if (tok == ':') {
/* new label */
asm_new_label(s1, opcode, 0);
next();
goto redo;
} else if (tok == '=') {
int n;
next();
n = asm_int_expr(s1);
asm_new_label1(s1, opcode, 0, SHN_ABS, n);
goto redo;
} else {
asm_opcode(s1, opcode);
}
}
/* end of line */
if (tok != ';' && tok != TOK_LINEFEED){
expect("end of line");
}
parse_flags &= ~PARSE_FLAG_LINEFEED; /* XXX: suppress that hack */
next();
}
asm_free_labels(s1);
return 0;
}
/* Assemble the current file */
static int tcc_assemble(TCCState *s1, int do_preprocess)
{
Sym *define_start;
int ret;
preprocess_init(s1);
/* default section is text */
cur_text_section = text_section;
ind = cur_text_section->data_offset;
define_start = define_stack;
ret = tcc_assemble_internal(s1, do_preprocess);
cur_text_section->data_offset = ind;
free_defines(define_start);
return ret;
}
/********************************************************************/
/* GCC inline asm support */
/* assemble the string 'str' in the current C compilation unit without
C preprocessing. NOTE: str is modified by modifying the '\0' at the
end */
static void tcc_assemble_inline(TCCState *s1, char *str, int len)
{
BufferedFile *bf, *saved_file;
int saved_parse_flags, *saved_macro_ptr;
bf = tcc_malloc(sizeof(BufferedFile));
memset(bf, 0, sizeof(BufferedFile));
bf->fd = -1;
bf->buf_ptr = str;
bf->buf_end = str + len;
str[len] = CH_EOB;
/* same name as current file so that errors are correctly
reported */
pstrcpy(bf->filename, sizeof(bf->filename), file->filename);
bf->line_num = file->line_num;
saved_file = file;
file = bf;
saved_parse_flags = parse_flags;
saved_macro_ptr = macro_ptr;
macro_ptr = NULL;
tcc_assemble_internal(s1, 0);
parse_flags = saved_parse_flags;
macro_ptr = saved_macro_ptr;
file = saved_file;
tcc_free(bf);
}
/* find a constraint by its number or id (gcc 3 extended
syntax). return -1 if not found. Return in *pp in char after the
constraint */
static int find_constraint(ASMOperand *operands, int nb_operands,
const char *name, const char **pp)
{
int index;
TokenSym *ts;
const char *p;
if (isnum(*name)) {
index = 0;
while (isnum(*name)) {
index = (index * 10) + (*name) - '0';
name++;
}
if ((unsigned)index >= nb_operands)
index = -1;
} else if (*name == '[') {
name++;
p = strchr(name, ']');
if (p) {
ts = tok_alloc(name, p - name);
for(index = 0; index < nb_operands; index++) {
if (operands[index].id == ts->tok)
goto found;
}
index = -1;
found:
name = p + 1;
} else {
index = -1;
}
} else {
index = -1;
}
if (pp)
*pp = name;
return index;
}
static void subst_asm_operands(ASMOperand *operands, int nb_operands,
int nb_outputs,
CString *out_str, CString *in_str)
{
int c, index, modifier;
const char *str;
ASMOperand *op;
SValue sv;
cstr_new(out_str);
str = in_str->data;
for(;;) {
c = *str++;
if (c == '%') {
if (*str == '%') {
str++;
goto add_char;
}
modifier = 0;
if (*str == 'c' || *str == 'n' ||
*str == 'b' || *str == 'w' || *str == 'h')
modifier = *str++;
index = find_constraint(operands, nb_operands, str, &str);
if (index < 0)
error("invalid operand reference after %%");
op = &operands[index];
sv = *op->vt;
if (op->reg >= 0) {
sv.r = op->reg;
if ((op->vt->r & VT_VALMASK) == VT_LLOCAL && op->is_memory)
sv.r |= VT_LVAL;
}
subst_asm_operand(out_str, &sv, modifier);
} else {
add_char:
cstr_ccat(out_str, c);
if (c == '\0')
break;
}
}
}
static void parse_asm_operands(ASMOperand *operands, int *nb_operands_ptr,
int is_output)
{
ASMOperand *op;
int nb_operands;
if (tok != ':') {
nb_operands = *nb_operands_ptr;
for(;;) {
if (nb_operands >= MAX_ASM_OPERANDS)
error("too many asm operands");
op = &operands[nb_operands++];
op->id = 0;
if (tok == '[') {
next();
if (tok < TOK_IDENT)
expect("identifier");
op->id = tok;
next();
skip(']');
}
if (tok != TOK_STR)
expect("string constant");
op->constraint = tcc_malloc(tokc.cstr->size);
strcpy(op->constraint, tokc.cstr->data);
next();
skip('(');
gexpr();
if (is_output) {
test_lvalue();
} else {
/* we want to avoid LLOCAL case, except when the 'm'
constraint is used. Note that it may come from
register storage, so we need to convert (reg)
case */
if ((vtop->r & VT_LVAL) &&
((vtop->r & VT_VALMASK) == VT_LLOCAL ||
(vtop->r & VT_VALMASK) < VT_CONST) &&
!strchr(op->constraint, 'm')) {
gv(RC_INT);
}
}
op->vt = vtop;
skip(')');
if (tok == ',') {
next();
} else {
break;
}
}
*nb_operands_ptr = nb_operands;
}
}
static void parse_asm_str(CString *astr)
{
skip('(');
/* read the string */
if (tok != TOK_STR)
expect("string constant");
cstr_new(astr);
while (tok == TOK_STR) {
/* XXX: add \0 handling too ? */
cstr_cat(astr, tokc.cstr->data);
next();
}
cstr_ccat(astr, '\0');
}
/* parse the GCC asm() instruction */
static void asm_instr(void)
{
CString astr, astr1;
ASMOperand operands[MAX_ASM_OPERANDS];
int nb_inputs, nb_outputs, nb_operands, i, must_subst, out_reg;
uint8_t clobber_regs[NB_ASM_REGS];
next();
/* since we always generate the asm() instruction, we can ignore
volatile */
if (tok == TOK_VOLATILE1 || tok == TOK_VOLATILE2 || tok == TOK_VOLATILE3) {
next();
}
parse_asm_str(&astr);
nb_operands = 0;
nb_outputs = 0;
must_subst = 0;
memset(clobber_regs, 0, sizeof(clobber_regs));
if (tok == ':') {
next();
must_subst = 1;
/* output args */
parse_asm_operands(operands, &nb_operands, 1);
nb_outputs = nb_operands;
if (tok == ':') {
next();
if (tok != ')') {
/* input args */
parse_asm_operands(operands, &nb_operands, 0);
if (tok == ':') {
/* clobber list */
/* XXX: handle registers */
next();
for(;;) {
if (tok != TOK_STR)
expect("string constant");
asm_clobber(clobber_regs, tokc.cstr->data);
next();
if (tok == ',') {
next();
} else {
break;
}
}
}
}
}
}
skip(')');
/* NOTE: we do not eat the ';' so that we can restore the current
token after the assembler parsing */
if (tok != ';')
expect("';'");
nb_inputs = nb_operands - nb_outputs;
/* save all values in the memory */
save_regs(0);
/* compute constraints */
asm_compute_constraints(operands, nb_operands, nb_outputs,
clobber_regs, &out_reg);
/* substitute the operands in the asm string. No substitution is
done if no operands (GCC behaviour) */
#ifdef ASM_DEBUG
printf("asm: \"%s\"\n", (char *)astr.data);
#endif
if (must_subst) {
subst_asm_operands(operands, nb_operands, nb_outputs, &astr1, &astr);
cstr_free(&astr);
} else {
astr1 = astr;
}
#ifdef ASM_DEBUG
printf("subst_asm: \"%s\"\n", (char *)astr1.data);
#endif
/* generate loads */
asm_gen_code(operands, nb_operands, nb_outputs, 0,
clobber_regs, out_reg);
/* assemble the string with tcc internal assembler */
tcc_assemble_inline(tcc_state, astr1.data, astr1.size - 1);
/* restore the current C token */
next();
/* store the output values if needed */
asm_gen_code(operands, nb_operands, nb_outputs, 1,
clobber_regs, out_reg);
/* free everything */
for(i=0;i<nb_operands;i++) {
ASMOperand *op;
op = &operands[i];
tcc_free(op->constraint);
vpop();
}
cstr_free(&astr1);
}
static void asm_global_instr(void)
{
CString astr;
next();
parse_asm_str(&astr);
skip(')');