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Revert "Implement C99 Variable Length Arrays"

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This reverts commit a5a50eaafe.
This commit is contained in:
Thomas Preud'homme 2011-02-05 02:31:45 +01:00
parent 38f6467c06
commit db560e9439
6 changed files with 33 additions and 169 deletions
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1
Changelog
View file

@ -12,7 +12,6 @@ not released:
- fix 32 to 64 bit casts, alignment and struct issues (Shinichiro Hamaji)
- mimic all GNU -option forms supported by ld (Kirill Smelkov)
- support indirect functions as externals (Thomas Preud'homme)
- Add support for C99 variable length arrays (Thomas Preud'homme)
version 0.9.25:

1
TODO
View file

@ -48,6 +48,7 @@ Missing features:
- improve '-E' option.
- atexit (Nigel Horne)
- packed attribute
- C99: add variable size arrays (gcc 3.2 testsuite issue)
- C99: add complex types (gcc 3.2 testsuite issue)
- postfix compound literals (see 20010124-1.c)

16
tcc-doc.texi
View file

@ -929,11 +929,7 @@ be the best solution.
#define VT_BTYPE 0x000f /* mask for basic type */
#define VT_UNSIGNED 0x0010 /* unsigned type */
#define VT_ARRAY 0x0020 /* array type (also has VT_PTR) */
#define VT_VLA 0x10000 /* VLA type (also has VT_PTR and VT_ARRAY) */
#define VT_BITFIELD 0x0040 /* bitfield modifier */
#define VT_CONSTANT 0x0800 /* const modifier */
#define VT_VOLATILE 0x1000 /* volatile modifier */
#define VT_SIGNED 0x2000 /* signed type */
#define VT_STRUCT_SHIFT 18 /* structure/enum name shift (14 bits left) */
@end example
@ -946,8 +942,7 @@ The @code{VT_UNSIGNED} flag can be set for chars, shorts, ints and long
longs.
Arrays are considered as pointers @code{VT_PTR} with the flag
@code{VT_ARRAY} set. Variable length arrays are considered as special
arrays and therefore also have flag @code{VT_VLA} set.
@code{VT_ARRAY} set.
The @code{VT_BITFIELD} flag can be set for chars, shorts, ints and long
longs. If it is set, then the bitfield position is stored from bits
@ -963,10 +958,6 @@ integer:
#define VT_EXTERN 0x00000080 /* extern definition */
#define VT_STATIC 0x00000100 /* static variable */
#define VT_TYPEDEF 0x00000200 /* typedef definition */
#define VT_INLINE 0x00000400 /* inline definition */
#define VT_IMPORT 0x00004000 /* win32: extern data imported from dll */
#define VT_EXPORT 0x00008000 /* win32: data exported from dll */
#define VT_WEAK 0x00010000 /* win32: data exported from dll */
@end example
@section Symbols
@ -978,10 +969,7 @@ contains @code{Sym} structures.
an idenfier is also a token, so a string is never necessary to store
it). @code{Sym.t} gives the type of the symbol. @code{Sym.r} is usually
the register in which the corresponding variable is stored. @code{Sym.c} is
usually a constant associated to the symbol like its address for normal
symbols, and the number of entries for symbols representing arrays.
Variable length arrays use @code{Sym.r} instead, which is a pointer to
a @code{SValue} holding its runtime size.
usually a constant associated to the symbol.
Four main symbol stacks are defined:

2
tcc.h
View file

@ -224,7 +224,6 @@ typedef struct Sym {
union {
long c; /* associated number */
int *d; /* define token stream */
SValue *s; /* associated stack value */
};
CType type; /* associated type */
union {
@ -617,7 +616,6 @@ struct TCCState {
#define VT_BTYPE 0x000f /* mask for basic type */
#define VT_UNSIGNED 0x0010 /* unsigned type */
#define VT_ARRAY 0x0020 /* array type (also has VT_PTR) */
#define VT_VLA 0x10000 /* VLA type (also has VT_PTR and VT_ARRAY) */
#define VT_BITFIELD 0x0040 /* bitfield modifier */
#define VT_CONSTANT 0x0800 /* const modifier */
#define VT_VOLATILE 0x1000 /* volatile modifier */

160
tccgen.c
View file

@ -78,7 +78,6 @@ static void block(int *bsym, int *csym, int *case_sym, int *def_sym, int case_re
static void decl_initializer_alloc(CType *type, AttributeDef *ad, int r, int has_init, int v, int scope);
static void expr_eq(void);
static void unary_type(CType *type);
static void vla_runtime_type_size(CType *type, int *a);
static int is_compatible_parameter_types(CType *type1, CType *type2);
static void expr_type(CType *type);
@ -1456,12 +1455,6 @@ static int pointed_size(CType *type)
return type_size(pointed_type(type), &align);
}
static void vla_runtime_pointed_size(CType *type)
{
int align;
vla_runtime_type_size(pointed_type(type), &align);
}
static inline int is_null_pointer(SValue *p)
{
if ((p->r & (VT_VALMASK | VT_LVAL | VT_SYM)) != VT_CONST)
@ -1550,20 +1543,11 @@ ST_FUNC void gen_op(int op)
}
/* if both pointers, then it must be the '-' op */
if (bt1 == VT_PTR && bt2 == VT_PTR) {
int ptr1_is_vla;
ptr1_is_vla = 0;
if (op != '-')
error("cannot use pointers here");
check_comparison_pointer_types(vtop - 1, vtop, op);
/* XXX: check that types are compatible */
if (vtop[-1].type.t & VT_VLA) {
vla_runtime_pointed_size(&vtop[-1].type);
vrott(3);
ptr1_is_vla = 1;
} else {
u = pointed_size(&vtop[-1].type);
}
u = pointed_size(&vtop[-1].type);
gen_opic(op);
/* set to integer type */
#ifdef TCC_TARGET_X86_64
@ -1571,10 +1555,7 @@ ST_FUNC void gen_op(int op)
#else
vtop->type.t = VT_INT;
#endif
if (ptr1_is_vla)
vswap();
else
vpushi(u);
vpushi(u);
gen_op(TOK_PDIV);
} else {
/* exactly one pointer : must be '+' or '-'. */
@ -1586,20 +1567,16 @@ ST_FUNC void gen_op(int op)
swap(&t1, &t2);
}
type1 = vtop[-1].type;
type1.t &= ~(VT_ARRAY|VT_VLA);
if (vtop[-1].type.t & VT_VLA)
vla_runtime_pointed_size(&vtop[-1].type);
else {
u = pointed_size(&vtop[-1].type);
if (u < 0)
error("unknown array element size");
type1.t &= ~VT_ARRAY;
u = pointed_size(&vtop[-1].type);
if (u < 0)
error("unknown array element size");
#ifdef TCC_TARGET_X86_64
vpushll(u);
vpushll(u);
#else
/* XXX: cast to int ? (long long case) */
vpushi(u);
/* XXX: cast to int ? (long long case) */
vpushi(u);
#endif
}
gen_op('*');
#ifdef CONFIG_TCC_BCHECK
/* if evaluating constant expression, no code should be
@ -1955,7 +1932,7 @@ static void gen_cast(CType *type)
vtop->type = *type;
}
/* return type size as known at compile time. Put alignment at 'a' */
/* return type size. Put alignment at 'a' */
ST_FUNC int type_size(CType *type, int *a)
{
Sym *s;
@ -1968,10 +1945,7 @@ ST_FUNC int type_size(CType *type, int *a)
*a = s->r;
return s->c;
} else if (bt == VT_PTR) {
if (type->t & VT_VLA) {
*a = 1;
return 0;
} else if (type->t & VT_ARRAY) {
if (type->t & VT_ARRAY) {
int ts;
s = type->ref;
@ -2018,30 +1992,6 @@ ST_FUNC int type_size(CType *type, int *a)
}
}
/* push type size as known at runtime time on top of value stack. Put
alignment at 'a' */
ST_FUNC void vla_runtime_type_size(CType *type, int *a)
{
if (type->t & VT_VLA) {
Sym *s;
s = type->ref;
vla_runtime_type_size(&s->type, a);
vpushv(s->s);
if ((vtop->r & (VT_SYM|VT_LVAL|VT_VALMASK)) != VT_CONST) {
gv_dup();
vswap();
vpop();
}
gen_op('*');
} else {
int size;
size = type_size(type, a);
vpushi(size);
}
}
/* return the pointed type of t */
static inline CType *pointed_type(CType *type)
{
@ -3153,43 +3103,25 @@ static void post_type(CType *type, AttributeDef *ad)
type->t = t1 | VT_FUNC;
type->ref = s;
} else if (tok == '[') {
SValue *last_vtop = NULL;
/* array definition */
next();
if (tok == TOK_RESTRICT1)
next();
n = -1;
if (tok != ']') {
gexpr();
if ((vtop->r & (VT_VALMASK | VT_LVAL | VT_SYM)) == VT_CONST) {
n = vtop->c.i;
last_vtop = vtop;
if (n < 0)
error("invalid array size");
} else {
if (!is_integer_btype(vtop->type.t & VT_BTYPE))
error("size of variable length array should be an integer");
type->t |= VT_VLA;
last_vtop = vtop;
}
n = expr_const();
if (n < 0)
error("invalid array size");
}
skip(']');
/* parse next post type */
t1 = type->t & (VT_STORAGE|VT_VLA);
type->t &= ~(VT_STORAGE|VT_VLA);
t1 = type->t & VT_STORAGE;
type->t &= ~VT_STORAGE;
post_type(type, ad);
t1 |= type->t & VT_VLA;
/* we push an anonymous symbol which will contain the array
/* we push a anonymous symbol which will contain the array
element type */
s = sym_push(SYM_FIELD, type, 0, n);
if (t1 & VT_VLA) {
s->s = last_vtop; // That's ok, we don't need n with VLA
} else {
if (n >= 0)
vpop();
}
type->t = t1 | VT_ARRAY | VT_PTR;
type->ref = s;
}
@ -3558,18 +3490,11 @@ ST_FUNC void unary(void)
next();
in_sizeof++;
unary_type(&type); // Perform a in_sizeof = 0;
if ((t == TOK_SIZEOF) && (type.t & VT_VLA)) {
vla_runtime_type_size(&type, &align);
size = 0;
} else {
size = type_size(&type, &align);
}
size = type_size(&type, &align);
if (t == TOK_SIZEOF) {
if (!(type.t & VT_VLA)) {
if (size < 0)
error("sizeof applied to an incomplete type");
vpushi(size);
}
if (size < 0)
error("sizeof applied to an incomplete type");
vpushi(size);
} else {
vpushi(align);
}
@ -3728,10 +3653,7 @@ ST_FUNC void unary(void)
} else {
r = s->r;
}
if (s->type.t & VT_VLA)
vpushv(s->s);
else
vset(&s->type, r, s->c);
vset(&s->type, r, s->c);
/* if forward reference, we must point to s */
if (vtop->r & VT_SYM) {
vtop->sym = s;
@ -4860,18 +4782,7 @@ static void decl_initializer(CType *type, Section *sec, unsigned long c,
Sym *s, *f;
CType *t1;
if (type->t & VT_VLA) {
int a;
CValue retcval;
vpush_global_sym(&func_old_type, TOK_alloca);
vla_runtime_type_size(type, &a);
gfunc_call(1);
/* return value */
retcval.i = 0;
vsetc(type, REG_IRET, &retcval);
} else if (type->t & VT_ARRAY) {
if (type->t & VT_ARRAY) {
s = type->ref;
n = s->c;
array_length = 0;
@ -5102,7 +5013,6 @@ static void decl_initializer_alloc(CType *type, AttributeDef *ad, int r,
ParseState saved_parse_state = {0};
TokenString init_str;
Section *sec;
Sym *vla = NULL;
size = type_size(type, &align);
/* If unknown size, we must evaluate it before
@ -5168,12 +5078,8 @@ static void decl_initializer_alloc(CType *type, AttributeDef *ad, int r,
if ((r & VT_VALMASK) == VT_LOCAL) {
sec = NULL;
#ifdef CONFIG_TCC_BCHECK
if (tcc_state->do_bounds_check && (type->t & VT_ARRAY)) {
if (type->t & VT_VLA)
warning("Array bound check don't work for VLA");
else
loc--;
}
if (tcc_state->do_bounds_check && (type->t & VT_ARRAY))
loc--;
#endif
loc = (loc - size) & -align;
addr = loc;
@ -5181,8 +5087,7 @@ static void decl_initializer_alloc(CType *type, AttributeDef *ad, int r,
/* handles bounds */
/* XXX: currently, since we do only one pass, we cannot track
'&' operators, so we add only arrays */
if (tcc_state->do_bounds_check && (type->t & VT_ARRAY) &&
!(type->t & VT_VLA)) {
if (tcc_state->do_bounds_check && (type->t & VT_ARRAY)) {
unsigned long *bounds_ptr;
/* add padding between regions */
loc--;
@ -5194,7 +5099,7 @@ static void decl_initializer_alloc(CType *type, AttributeDef *ad, int r,
#endif
if (v) {
/* local variable */
vla = sym_push(v, type, r, addr);
sym_push(v, type, r, addr);
} else {
/* push local reference */
vset(type, r, addr);
@ -5309,10 +5214,8 @@ static void decl_initializer_alloc(CType *type, AttributeDef *ad, int r,
}
#endif
}
if (has_init || (type->t & VT_VLA)) {
if (has_init) {
decl_initializer(type, sec, addr, 1, 0);
if (type->t & VT_VLA)
vla->s = vtop;
/* restore parse state if needed */
if (init_str.str) {
tok_str_free(init_str.str);
@ -5681,12 +5584,9 @@ ST_FUNC void decl(int l)
if (!(type.t & VT_ARRAY))
r |= lvalue_type(type.t);
has_init = (tok == '=');
if (has_init && (type.t & VT_VLA))
error("Variable length array cannot be initialized");
if ((btype.t & VT_EXTERN) ||
((type.t & VT_ARRAY) && (!(type.t & VT_VLA)) &&
(type.t & VT_STATIC) && !has_init && l == VT_CONST &&
type.ref->c < 0)) {
((type.t & VT_ARRAY) && (type.t & VT_STATIC) &&
!has_init && l == VT_CONST && type.ref->c < 0)) {
/* external variable */
/* NOTE: as GCC, uninitialized global static
arrays of null size are considered as

22
tests/tcctest.c
View file

@ -77,7 +77,6 @@ void whitespace_test(void);
void relocation_test(void);
void old_style_function(void);
void alloca_test(void);
void c99_vla_test(int size1, int size2);
void sizeof_test(void);
void typeof_test(void);
void local_label_test(void);
@ -564,7 +563,6 @@ int main(int argc, char **argv)
relocation_test();
old_style_function();
alloca_test();
c99_vla_test(5, 2);
sizeof_test();
typeof_test();
statement_expr_test();
@ -2020,26 +2018,6 @@ void alloca_test()
#endif
}
void c99_vla_test(int size1, int size2)
{
#if defined __i386__ || defined __x86_64__
int tab1[size1 * size2][2], tab2[10][2];
void *tab1_ptr, *tab2_ptr;
printf("Test C99 VLA 1 (sizeof): ");
printf("%s\n", (sizeof tab1 == size1 * size2 * 2 * sizeof(int)) ? "PASSED" : "FAILED");
tab1_ptr = tab1;
tab2_ptr = tab2;
printf("Test C99 VLA 2 (ptrs substract): ");
printf("%s\n", (tab2 - tab1 == (tab2_ptr - tab1_ptr) / (sizeof(int) * 2)) ? "PASSED" : "FAILED");
printf("Test C99 VLA 3 (ptr add): ");
printf("%s\n", &tab1[5][1] == (tab1_ptr + (5 * 2 + 1) * sizeof(int)) ? "PASSED" : "FAILED");
printf("Test C99 VLA 4 (ptr access): ");
tab1[size1][1] = 42;
printf("%s\n", (*((int *) (tab1_ptr + (size1 * 2 + 1) * sizeof(int))) == 42) ? "PASSED" : "FAILED");
#endif
}
void sizeof_test(void)
{
int a;