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absolute symbols support - .org, .fill and .previous directives

tcc-xref
bellard 2004-10-18 00:19:51 +00:00
parent 9668499b9f
commit 0bd402d2eb
1 changed files with 189 additions and 36 deletions
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225
tccasm.c
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@ -28,6 +28,8 @@ static int asm_get_local_label_name(TCCState *s1, unsigned int n)
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. */
@ -91,6 +93,11 @@ static void asm_expr_unary(TCCState *s1, ExprValue *pe)
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 */
@ -100,8 +107,14 @@ static void asm_expr_unary(TCCState *s1, ExprValue *pe)
/* NOTE: by default, the symbol is global */
sym->type.t = VT_VOID;
}
pe->v = 0;
pe->sym = sym;
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));
@ -241,7 +254,8 @@ static int asm_int_expr(TCCState *s1)
/* 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_label(TCCState *s1, int label, int is_local)
static void asm_new_label1(TCCState *s1, int label, int is_local,
int sh_num, int value)
{
Sym *sym;
@ -262,18 +276,29 @@ static void asm_new_label(TCCState *s1, int label, int is_local)
sym = label_push(&s1->asm_labels, label, 0);
sym->type.t = VT_STATIC | VT_VOID;
}
sym->r = cur_text_section->sh_num;
sym->next = (void *)ind;
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) {
put_extern_sym(s, st->sections[s->r], (long)s->next, 0);
if (s->r == SHN_ABS)
sec = SECTION_ABS;
else
sec = st->sections[s->r];
put_extern_sym(s, sec, (long)s->next, 0);
}
/* remove label */
table_ident[s->v - TOK_IDENT]->sym_label = NULL;
@ -282,13 +307,18 @@ static void asm_free_labels(TCCState *st)
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);
cur_text_section->data_offset = ind;
cur_text_section = sec;
ind = cur_text_section->data_offset;
use_section1(s1, sec);
}
static void asm_parse_directive(TCCState *s1)
@ -312,6 +342,9 @@ static void asm_parse_directive(TCCState *s1)
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;
}
@ -320,6 +353,7 @@ static void asm_parse_directive(TCCState *s1)
next();
v = asm_int_expr(s1);
}
zero_pad:
if (sec->sh_type != SHT_NOBITS) {
sec->data_offset = ind;
ptr = section_ptr_add(sec, size);
@ -361,6 +395,61 @@ static void asm_parse_directive(TCCState *s1)
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:
{
@ -420,9 +509,28 @@ static void asm_parse_directive(TCCState *s1)
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;
@ -471,7 +579,7 @@ static int tcc_assemble_internal(TCCState *s1, int do_preprocess)
ch = file->buf_ptr[0];
tok_flags = TOK_FLAG_BOL | TOK_FLAG_BOF;
parse_flags = 0;
parse_flags = PARSE_FLAG_ASM_COMMENTS;
if (do_preprocess)
parse_flags |= PARSE_FLAG_PREPROCESS;
next();
@ -507,6 +615,12 @@ static int tcc_assemble_internal(TCCState *s1, int do_preprocess)
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);
}
@ -527,6 +641,7 @@ static int tcc_assemble_internal(TCCState *s1, int do_preprocess)
/* Assemble the current file */
static int tcc_assemble(TCCState *s1, int do_preprocess)
{
Sym *define_start;
int ret;
preprocess_init(s1);
@ -535,9 +650,14 @@ static int tcc_assemble(TCCState *s1, int do_preprocess)
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;
}
@ -691,12 +811,14 @@ static void parse_asm_operands(ASMOperand *operands, int *nb_operands_ptr,
if (is_output) {
test_lvalue();
} else {
/* we want to avoid LLOCAL case. note that it may come
from register storage, so we need to convert (reg)
/* 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)) {
(vtop->r & VT_VALMASK) < VT_CONST) &&
!strchr(op->constraint, 'm')) {
gv(RC_INT);
}
}
@ -712,14 +834,27 @@ static void parse_asm_operands(ASMOperand *operands, int *nb_operands_ptr,
}
}
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;
uint8_t input_regs_allocated[NB_ASM_REGS];
uint8_t output_regs_allocated[NB_ASM_REGS];
int nb_inputs, nb_outputs, nb_operands, i, must_subst, out_reg;
uint8_t clobber_regs[NB_ASM_REGS];
next();
@ -728,22 +863,14 @@ static void asm_instr(void)
if (tok == TOK_VOLATILE1 || tok == TOK_VOLATILE2 || tok == TOK_VOLATILE3) {
next();
}
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_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;
@ -780,19 +907,15 @@ static void asm_instr(void)
save_regs(0);
/* compute constraints */
asm_compute_constraints(input_regs_allocated,
operands, nb_operands, nb_outputs, 0,
NULL);
asm_compute_constraints(output_regs_allocated,
operands, nb_operands, nb_outputs, 1,
input_regs_allocated);
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 (nb_operands > 0) {
if (must_subst) {
subst_asm_operands(operands, nb_operands, nb_outputs, &astr1, &astr);
cstr_free(&astr);
} else {
@ -803,7 +926,8 @@ static void asm_instr(void)
#endif
/* generate loads */
asm_gen_code(operands, nb_operands, nb_outputs, 0, clobber_regs);
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);
@ -812,7 +936,8 @@ static void asm_instr(void)
next();
/* store the output values if needed */
asm_gen_code(operands, nb_operands, nb_outputs, 1, clobber_regs);
asm_gen_code(operands, nb_operands, nb_outputs, 1,
clobber_regs, out_reg);
/* free everything */
for(i=0;i<nb_operands;i++) {
@ -824,3 +949,31 @@ static void asm_instr(void)
cstr_free(&astr1);
}
static void asm_global_instr(void)
{
CString astr;
next();
parse_asm_str(&astr);
skip(')');
/* NOTE: we do not eat the ';' so that we can restore the current
token after the assembler parsing */
if (tok != ';')
expect("';'");
#ifdef ASM_DEBUG
printf("asm_global: \"%s\"\n", (char *)astr.data);
#endif
cur_text_section = text_section;
ind = cur_text_section->data_offset;
/* assemble the string with tcc internal assembler */
tcc_assemble_inline(tcc_state, astr.data, astr.size - 1);
cur_text_section->data_offset = ind;
/* restore the current C token */
next();
cstr_free(&astr);
}