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about CONST_WANTED & VT_NONCONST

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- integrate CONST_WANTED with nocode_wanted
- expr_const() checks VT_NONCONST
This commit is contained in:
grischka 2023-03-12 11:16:27 +01:00
parent bb93bf8cd2
commit 0ec3a40dfd
2 changed files with 35 additions and 30 deletions
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1
tcc.h
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@ -1421,7 +1421,6 @@ ST_DATA SValue *vtop;
ST_DATA int rsym, anon_sym, ind, loc; ST_DATA int rsym, anon_sym, ind, loc;
ST_DATA char debug_modes; ST_DATA char debug_modes;
ST_DATA int const_wanted; /* true if constant wanted */
ST_DATA int nocode_wanted; /* true if no code generation wanted for an expression */ ST_DATA int nocode_wanted; /* true if no code generation wanted for an expression */
ST_DATA int global_expr; /* true if compound literals must be allocated globally (used during initializers parsing */ ST_DATA int global_expr; /* true if compound literals must be allocated globally (used during initializers parsing */
ST_DATA CType func_vt; /* current function return type (used by return instruction) */ ST_DATA CType func_vt; /* current function return type (used by return instruction) */

64
tccgen.c
View file

@ -51,15 +51,24 @@ ST_DATA SValue *vtop;
static SValue _vstack[1 + VSTACK_SIZE]; static SValue _vstack[1 + VSTACK_SIZE];
#define vstack (_vstack + 1) #define vstack (_vstack + 1)
ST_DATA int const_wanted; /* true if constant wanted */
ST_DATA int nocode_wanted; /* no code generation wanted */ ST_DATA int nocode_wanted; /* no code generation wanted */
#define unevalmask 0xffff /* unevaluated subexpression */
#define NODATA_WANTED (nocode_wanted > 0) /* no static data output wanted either */ #define NODATA_WANTED (nocode_wanted > 0) /* no static data output wanted either */
#define DATA_ONLY_WANTED 0x80000000 /* ON outside of functions and for static initializers */ #define DATA_ONLY_WANTED 0x80000000 /* ON outside of functions and for static initializers */
/* no code output after unconditional jumps such as with if (0) ... */
#define CODE_OFF_BIT 0x20000000 #define CODE_OFF_BIT 0x20000000
#define CODE_OFF() if(!nocode_wanted)(nocode_wanted |= CODE_OFF_BIT) #define CODE_OFF() if(!nocode_wanted)(nocode_wanted |= CODE_OFF_BIT)
#define CODE_ON() (nocode_wanted &= ~CODE_OFF_BIT) #define CODE_ON() (nocode_wanted &= ~CODE_OFF_BIT)
/* no code output when parsing sizeof()/typeof() etc. (using nocode_wanted++/--) */
#define NOEVAL_MASK 0x0000FFFF
#define NOEVAL_WANTED (nocode_wanted & NOEVAL_MASK)
/* no code output when parsing constant expressions */
#define CONST_WANTED_BIT 0x00010000
#define CONST_WANTED_MASK 0x0FFF0000
#define CONST_WANTED (nocode_wanted & CONST_WANTED_MASK)
ST_DATA int global_expr; /* true if compound literals must be allocated globally (used during initializers parsing */ ST_DATA int global_expr; /* true if compound literals must be allocated globally (used during initializers parsing */
ST_DATA CType func_vt; /* current function return type (used by return instruction) */ ST_DATA CType func_vt; /* current function return type (used by return instruction) */
ST_DATA int func_var; /* true if current function is variadic (used by return instruction) */ ST_DATA int func_var; /* true if current function is variadic (used by return instruction) */
@ -375,7 +384,6 @@ ST_FUNC int tccgen_compile(TCCState *s1)
funcname = ""; funcname = "";
func_ind = -1; func_ind = -1;
anon_sym = SYM_FIRST_ANOM; anon_sym = SYM_FIRST_ANOM;
const_wanted = 0;
nocode_wanted = DATA_ONLY_WANTED; /* no code outside of functions */ nocode_wanted = DATA_ONLY_WANTED; /* no code outside of functions */
local_scope = 0; local_scope = 0;
debug_modes = (s1->do_debug ? 1 : 0) | s1->test_coverage << 1; debug_modes = (s1->do_debug ? 1 : 0) | s1->test_coverage << 1;
@ -2274,10 +2282,10 @@ static void gen_opic(int op)
int t2 = v2->type.t & VT_BTYPE; int t2 = v2->type.t & VT_BTYPE;
int c1 = (v1->r & (VT_VALMASK | VT_LVAL | VT_SYM)) == VT_CONST; int c1 = (v1->r & (VT_VALMASK | VT_LVAL | VT_SYM)) == VT_CONST;
int c2 = (v2->r & (VT_VALMASK | VT_LVAL | VT_SYM)) == VT_CONST; int c2 = (v2->r & (VT_VALMASK | VT_LVAL | VT_SYM)) == VT_CONST;
int nonconst = (v1->r | v2->r) & VT_NONCONST;
uint64_t l1 = c1 ? v1->c.i : 0; uint64_t l1 = c1 ? v1->c.i : 0;
uint64_t l2 = c2 ? v2->c.i : 0; uint64_t l2 = c2 ? v2->c.i : 0;
int shm = (t1 == VT_LLONG) ? 63 : 31; int shm = (t1 == VT_LLONG) ? 63 : 31;
int r;
if (t1 != VT_LLONG && (PTR_SIZE != 8 || t1 != VT_PTR)) if (t1 != VT_LLONG && (PTR_SIZE != 8 || t1 != VT_PTR))
l1 = ((uint32_t)l1 | l1 = ((uint32_t)l1 |
@ -2302,7 +2310,7 @@ static void gen_opic(int op)
case TOK_UMOD: case TOK_UMOD:
/* if division by zero, generate explicit division */ /* if division by zero, generate explicit division */
if (l2 == 0) { if (l2 == 0) {
if (const_wanted && !(nocode_wanted & unevalmask)) if (CONST_WANTED && !NOEVAL_WANTED)
tcc_error("division by zero in constant"); tcc_error("division by zero in constant");
goto general_case; goto general_case;
} }
@ -2339,9 +2347,9 @@ static void gen_opic(int op)
l1 = ((uint32_t)l1 | l1 = ((uint32_t)l1 |
(v1->type.t & VT_UNSIGNED ? 0 : -(l1 & 0x80000000))); (v1->type.t & VT_UNSIGNED ? 0 : -(l1 & 0x80000000)));
v1->c.i = l1; v1->c.i = l1;
v1->r |= v2->r & VT_NONCONST;
vtop--; vtop--;
} else { } else {
nonconst = VT_NONCONST;
/* if commutative ops, put c2 as constant */ /* if commutative ops, put c2 as constant */
if (c1 && (op == '+' || op == '&' || op == '^' || if (c1 && (op == '+' || op == '&' || op == '^' ||
op == '|' || op == '*' || op == TOK_EQ || op == TOK_NE)) { op == '|' || op == '*' || op == TOK_EQ || op == TOK_NE)) {
@ -2349,14 +2357,12 @@ static void gen_opic(int op)
c2 = c1; //c = c1, c1 = c2, c2 = c; c2 = c1; //c = c1, c1 = c2, c2 = c;
l2 = l1; //l = l1, l1 = l2, l2 = l; l2 = l1; //l = l1, l1 = l2, l2 = l;
} }
if (!const_wanted && if (c1 && ((l1 == 0 &&
c1 && ((l1 == 0 &&
(op == TOK_SHL || op == TOK_SHR || op == TOK_SAR)) || (op == TOK_SHL || op == TOK_SHR || op == TOK_SAR)) ||
(l1 == -1 && op == TOK_SAR))) { (l1 == -1 && op == TOK_SAR))) {
/* treat (0 << x), (0 >> x) and (-1 >> x) as constant */ /* treat (0 << x), (0 >> x) and (-1 >> x) as constant */
vtop--; vpop();
} else if (!const_wanted && } else if (c2 && ((l2 == 0 && (op == '&' || op == '*')) ||
c2 && ((l2 == 0 && (op == '&' || op == '*')) ||
(op == '|' && (op == '|' &&
(l2 == -1 || (l2 == 0xFFFFFFFF && t2 != VT_LLONG))) || (l2 == -1 || (l2 == 0xFFFFFFFF && t2 != VT_LLONG))) ||
(l2 == 1 && (op == '%' || op == TOK_UMOD)))) { (l2 == 1 && (op == '%' || op == TOK_UMOD)))) {
@ -2393,8 +2399,8 @@ static void gen_opic(int op)
} }
goto general_case; goto general_case;
} else if (c2 && (op == '+' || op == '-') && } else if (c2 && (op == '+' || op == '-') &&
(((vtop[-1].r & (VT_VALMASK | VT_LVAL | VT_SYM)) == (VT_CONST | VT_SYM)) (r = vtop[-1].r & (VT_VALMASK | VT_LVAL | VT_SYM),
|| (vtop[-1].r & (VT_VALMASK | VT_LVAL)) == VT_LOCAL)) { r == (VT_CONST | VT_SYM) || r == VT_LOCAL)) {
/* symbol + constant case */ /* symbol + constant case */
if (op == '-') if (op == '-')
l2 = -l2; l2 = -l2;
@ -2414,9 +2420,9 @@ static void gen_opic(int op)
else else
gen_opi(op); gen_opi(op);
} }
if (vtop->r == VT_CONST)
vtop->r |= VT_NONCONST; /* is const, but only by optimization */
} }
if (vtop->r == VT_CONST)
vtop->r |= nonconst;
} }
#if defined TCC_TARGET_X86_64 || defined TCC_TARGET_I386 #if defined TCC_TARGET_X86_64 || defined TCC_TARGET_I386
@ -2484,7 +2490,7 @@ static void gen_opif(int op)
} }
/* NOTE: we only do constant propagation if finite number (not /* NOTE: we only do constant propagation if finite number (not
NaN or infinity) (ANSI spec) */ NaN or infinity) (ANSI spec) */
if (!(ieee_finite(f1) || !ieee_finite(f2)) && !const_wanted) if (!(ieee_finite(f1) || !ieee_finite(f2)) && !CONST_WANTED)
goto general_case; goto general_case;
switch(op) { switch(op) {
case '+': f1 += f2; break; case '+': f1 += f2; break;
@ -2495,7 +2501,7 @@ static void gen_opif(int op)
union { float f; unsigned u; } x1, x2, y; union { float f; unsigned u; } x1, x2, y;
/* If not in initializer we need to potentially generate /* If not in initializer we need to potentially generate
FP exceptions at runtime, otherwise we want to fold. */ FP exceptions at runtime, otherwise we want to fold. */
if (!const_wanted) if (!CONST_WANTED)
goto general_case; goto general_case;
/* the run-time result of 0.0/0.0 on x87, also of other compilers /* the run-time result of 0.0/0.0 on x87, also of other compilers
when used to compile the f1 /= f2 below, would be -nan */ when used to compile the f1 /= f2 below, would be -nan */
@ -2965,7 +2971,7 @@ redo:
vpush_type_size(pointed_type(&vtop[-1].type), &align); vpush_type_size(pointed_type(&vtop[-1].type), &align);
gen_op('*'); gen_op('*');
#ifdef CONFIG_TCC_BCHECK #ifdef CONFIG_TCC_BCHECK
if (tcc_state->do_bounds_check && !const_wanted) { if (tcc_state->do_bounds_check && !CONST_WANTED) {
/* if bounded pointers, we generate a special code to /* if bounded pointers, we generate a special code to
test bounds */ test bounds */
if (op == '-') { if (op == '-') {
@ -5533,7 +5539,7 @@ ST_FUNC void unary(void)
} }
} else if (tok == '{') { } else if (tok == '{') {
int saved_nocode_wanted = nocode_wanted; int saved_nocode_wanted = nocode_wanted;
if (const_wanted && !(nocode_wanted & unevalmask)) if (CONST_WANTED && !NOEVAL_WANTED)
expect("constant"); expect("constant");
if (0 == local_scope) if (0 == local_scope)
tcc_error("statement expression outside of function"); tcc_error("statement expression outside of function");
@ -5848,17 +5854,19 @@ ST_FUNC void unary(void)
int has_match = 0; int has_match = 0;
int learn = 0; int learn = 0;
TokenString *str = NULL; TokenString *str = NULL;
int saved_const_wanted = const_wanted; int saved_nocode_wanted = nocode_wanted;
nocode_wanted &= ~CONST_WANTED_MASK;
next(); next();
skip('('); skip('(');
const_wanted = 0;
expr_type(&controlling_type, expr_eq); expr_type(&controlling_type, expr_eq);
controlling_type.t &= ~(VT_CONSTANT | VT_VOLATILE | VT_ARRAY); controlling_type.t &= ~(VT_CONSTANT | VT_VOLATILE | VT_ARRAY);
if ((controlling_type.t & VT_BTYPE) == VT_FUNC) if ((controlling_type.t & VT_BTYPE) == VT_FUNC)
mk_pointer(&controlling_type); mk_pointer(&controlling_type);
const_wanted = saved_const_wanted;
for (;;) { nocode_wanted = saved_nocode_wanted;
for (;;) {
learn = 0; learn = 0;
skip(','); skip(',');
if (tok == TOK_DEFAULT) { if (tok == TOK_DEFAULT) {
@ -6532,11 +6540,9 @@ ST_FUNC void gexpr(void)
/* parse a constant expression and return value in vtop. */ /* parse a constant expression and return value in vtop. */
static void expr_const1(void) static void expr_const1(void)
{ {
const_wanted++; nocode_wanted += CONST_WANTED_BIT;
nocode_wanted += unevalmask + 1;
expr_cond(); expr_cond();
nocode_wanted -= unevalmask + 1; nocode_wanted -= CONST_WANTED_BIT;
const_wanted--;
} }
/* parse an integer constant and return its value. */ /* parse an integer constant and return its value. */
@ -6544,7 +6550,7 @@ static inline int64_t expr_const64(void)
{ {
int64_t c; int64_t c;
expr_const1(); expr_const1();
if ((vtop->r & (VT_VALMASK | VT_LVAL | VT_SYM)) != VT_CONST) if ((vtop->r & (VT_VALMASK | VT_LVAL | VT_SYM | VT_NONCONST)) != VT_CONST)
expect("constant expression"); expect("constant expression");
c = vtop->c.i; c = vtop->c.i;
vpop(); vpop();