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Unified Diff: src/third_party/dtoa/dtoa.c

Issue 3172008: Fix strict aliasing rule violations in dtoa.c. (Closed)
Patch Set: Created 10 years, 4 months ago
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Index: src/third_party/dtoa/dtoa.c
diff --git a/src/third_party/dtoa/dtoa.c b/src/third_party/dtoa/dtoa.c
index 178b3d12d12c1b3c3584478d9cb5deadbae94acb..068ed949d01f0443d4772ec51cbd94ff263d49fa 100644
--- a/src/third_party/dtoa/dtoa.c
+++ b/src/third_party/dtoa/dtoa.c
@@ -270,25 +270,14 @@ Exactly one of IEEE_8087, IEEE_MC68k, VAX, or IBM should be defined.
typedef union { double d; ULong L[2]; } U;
-#ifdef YES_ALIAS
-#define dval(x) x
#ifdef IEEE_8087
-#define word0(x) ((ULong *)&x)[1]
-#define word1(x) ((ULong *)&x)[0]
+#define word0(x) (x).L[1]
+#define word1(x) (x).L[0]
#else
-#define word0(x) ((ULong *)&x)[0]
-#define word1(x) ((ULong *)&x)[1]
-#endif
-#else
-#ifdef IEEE_8087
-#define word0(x) ((U*)&x)->L[1]
-#define word1(x) ((U*)&x)->L[0]
-#else
-#define word0(x) ((U*)&x)->L[0]
-#define word1(x) ((U*)&x)->L[1]
-#endif
-#define dval(x) ((U*)&x)->d
+#define word0(x) (x).L[0]
+#define word1(x) (x).L[1]
#endif
+#define dval(x) (x).d
/* The following definition of Storeinc is appropriate for MIPS processors.
* An alternative that might be better on some machines is
@@ -1108,13 +1097,15 @@ diff
static double
ulp
#ifdef KR_headers
- (x) double x;
+ (dx) double dx;
#else
- (double x)
+ (double dx)
#endif
{
register Long L;
- double a;
+ U x, a;
+
+ dval(x) = dx;
L = (word0(x) & Exp_mask) - (P-1)*Exp_msk1;
#ifndef Avoid_Underflow
@@ -1157,7 +1148,7 @@ b2d
{
ULong *xa, *xa0, w, y, z;
int k;
- double d;
+ U d;
#ifdef VAX
ULong d0, d1;
#else
@@ -1220,9 +1211,9 @@ b2d
static Bigint *
d2b
#ifdef KR_headers
- (d, e, bits) double d; int *e, *bits;
+ (dd, e, bits) double dd; int *e, *bits;
#else
- (double d, int *e, int *bits)
+ (double dd, int *e, int *bits)
#endif
{
Bigint *b;
@@ -1236,6 +1227,8 @@ d2b
d0 = word0(d) >> 16 | word0(d) << 16;
d1 = word1(d) >> 16 | word1(d) << 16;
#else
+ U d;
+ dval(d) = dd;
#define d0 word0(d)
#define d1 word1(d)
#endif
@@ -1368,7 +1361,7 @@ ratio
(Bigint *a, Bigint *b)
#endif
{
- double da, db;
+ U da, db;
int k, ka, kb;
dval(da) = b2d(a, &ka);
@@ -1542,7 +1535,8 @@ strtod
int bb2, bb5, bbe, bd2, bd5, bbbits, bs2, c, dsign,
e, e1, esign, i, j, k, nd, nd0, nf, nz, nz0, sign;
CONST char *s, *s0, *s1;
- double aadj, aadj1, adj, rv, rv0;
+ double aadj;
+ U aadj1, adj, rv, rv0;
Long L;
ULong y, z;
Bigint *bb = NULL, *bb1, *bd = NULL, *bd0, *bs = NULL, *delta = NULL;
@@ -2042,12 +2036,12 @@ strtod
}
if (rounding) {
if (dsign) {
- adj = 1.;
+ dval(adj) = 1.;
goto apply_adj;
}
}
else if (!dsign) {
- adj = -1.;
+ dval(adj) = -1.;
if (!word1(rv)
&& !(word0(rv) & Frac_mask)) {
y = word0(rv) & Exp_mask;
@@ -2059,7 +2053,7 @@ strtod
{
delta = lshift(delta,Log2P);
if (cmp(delta, bs) <= 0)
- adj = -0.5;
+ dval(adj) = -0.5;
}
}
apply_adj:
@@ -2072,26 +2066,26 @@ strtod
if ((word0(rv) & Exp_mask) <=
P*Exp_msk1) {
word0(rv) += P*Exp_msk1;
- dval(rv) += adj*ulp(dval(rv));
+ dval(rv) += dval(adj)*ulp(dval(rv));
word0(rv) -= P*Exp_msk1;
}
else
#endif /*Sudden_Underflow*/
#endif /*Avoid_Underflow*/
- dval(rv) += adj*ulp(dval(rv));
+ dval(rv) += dval(adj)*ulp(dval(rv));
}
break;
}
- adj = ratio(delta, bs);
- if (adj < 1.)
- adj = 1.;
- if (adj <= 0x7ffffffe) {
+ dval(adj) = ratio(delta, bs);
+ if (dval(adj) < 1.)
+ dval(adj) = 1.;
+ if (dval(adj) <= 0x7ffffffe) {
/* adj = rounding ? ceil(adj) : floor(adj); */
- y = adj;
- if (y != adj) {
+ y = dval(adj);
+ if (y != dval(adj)) {
if (!((rounding>>1) ^ dsign))
y++;
- adj = y;
+ dval(adj) = y;
}
}
#ifdef Avoid_Underflow
@@ -2101,21 +2095,21 @@ strtod
#ifdef Sudden_Underflow
if ((word0(rv) & Exp_mask) <= P*Exp_msk1) {
word0(rv) += P*Exp_msk1;
- adj *= ulp(dval(rv));
+ dval(adj) *= ulp(dval(rv));
if (dsign)
- dval(rv) += adj;
+ dval(rv) += dval(adj);
else
- dval(rv) -= adj;
+ dval(rv) -= dval(adj);
word0(rv) -= P*Exp_msk1;
goto cont;
}
#endif /*Sudden_Underflow*/
#endif /*Avoid_Underflow*/
- adj *= ulp(dval(rv));
+ dval(adj) *= ulp(dval(rv));
if (dsign)
- dval(rv) += adj;
+ dval(rv) += dval(adj);
else
- dval(rv) -= adj;
+ dval(rv) -= dval(adj);
goto cont;
}
#endif /*Honor_FLT_ROUNDS*/
@@ -2237,14 +2231,14 @@ strtod
}
if ((aadj = ratio(delta, bs)) <= 2.) {
if (dsign)
- aadj = aadj1 = 1.;
+ aadj = dval(aadj1) = 1.;
else if (word1(rv) || word0(rv) & Bndry_mask) {
#ifndef Sudden_Underflow
if (word1(rv) == Tiny1 && !word0(rv))
goto undfl;
#endif
aadj = 1.;
- aadj1 = -1.;
+ dval(aadj1) = -1.;
}
else {
/* special case -- power of FLT_RADIX to be */
@@ -2254,24 +2248,24 @@ strtod
aadj = 1./FLT_RADIX;
else
aadj *= 0.5;
- aadj1 = -aadj;
+ dval(aadj1) = -aadj;
}
}
else {
aadj *= 0.5;
- aadj1 = dsign ? aadj : -aadj;
+ dval(aadj1) = dsign ? aadj : -aadj;
#ifdef Check_FLT_ROUNDS
switch(Rounding) {
case 2: /* towards +infinity */
- aadj1 -= 0.5;
+ dval(aadj1) -= 0.5;
break;
case 0: /* towards 0 */
case 3: /* towards -infinity */
- aadj1 += 0.5;
+ dval(aadj1) += 0.5;
}
#else
if (Flt_Rounds == 0)
- aadj1 += 0.5;
+ dval(aadj1) += 0.5;
#endif /*Check_FLT_ROUNDS*/
}
y = word0(rv) & Exp_mask;
@@ -2281,8 +2275,8 @@ strtod
if (y == Exp_msk1*(DBL_MAX_EXP+Bias-1)) {
dval(rv0) = dval(rv);
word0(rv) -= P*Exp_msk1;
- adj = aadj1 * ulp(dval(rv));
- dval(rv) += adj;
+ dval(adj) = dval(aadj1) * ulp(dval(rv));
+ dval(rv) += dval(adj);
if ((word0(rv) & Exp_mask) >=
Exp_msk1*(DBL_MAX_EXP+Bias-P)) {
if (word0(rv0) == Big0 && word1(rv0) == Big1)
@@ -2301,19 +2295,19 @@ strtod
if ((z = aadj) <= 0)
z = 1;
aadj = z;
- aadj1 = dsign ? aadj : -aadj;
+ dval(aadj1) = dsign ? aadj : -aadj;
}
word0(aadj1) += (2*P+1)*Exp_msk1 - y;
}
- adj = aadj1 * ulp(dval(rv));
- dval(rv) += adj;
+ dval(adj) = dval(aadj1) * ulp(dval(rv));
+ dval(rv) += dval(adj);
#else
#ifdef Sudden_Underflow
if ((word0(rv) & Exp_mask) <= P*Exp_msk1) {
dval(rv0) = dval(rv);
word0(rv) += P*Exp_msk1;
- adj = aadj1 * ulp(dval(rv));
- dval(rv) += adj;
+ dval(adj) = dval(aadj1) * ulp(dval(rv));
+ dval(rv) += dval(adj);
#ifdef IBM
if ((word0(rv) & Exp_mask) < P*Exp_msk1)
#else
@@ -2331,8 +2325,8 @@ strtod
word0(rv) -= P*Exp_msk1;
}
else {
- adj = aadj1 * ulp(dval(rv));
- dval(rv) += adj;
+ dval(adj) = dval(aadj1) * ulp(dval(rv));
+ dval(rv) += dval(adj);
}
#else /*Sudden_Underflow*/
/* Compute adj so that the IEEE rounding rules will
@@ -2343,12 +2337,12 @@ strtod
* example: 1.2e-307 .
*/
if (y <= (P-1)*Exp_msk1 && aadj > 1.) {
- aadj1 = (double)(int)(aadj + 0.5);
+ dval(aadj1) = (double)(int)(aadj + 0.5);
if (!dsign)
- aadj1 = -aadj1;
+ dval(aadj1) = -dval(aadj1);
}
- adj = aadj1 * ulp(dval(rv));
- dval(rv) += adj;
+ dval(adj) = dval(aadj1) * ulp(dval(rv));
+ dval(rv) += dval(adj);
#endif /*Sudden_Underflow*/
#endif /*Avoid_Underflow*/
}
@@ -2638,10 +2632,10 @@ freedtoa(char *s)
char *
dtoa
#ifdef KR_headers
- (d, mode, ndigits, decpt, sign, rve)
- double d; int mode, ndigits, *decpt, *sign; char **rve;
+ (dd, mode, ndigits, decpt, sign, rve)
+ double dd; int mode, ndigits, *decpt, *sign; char **rve;
#else
- (double d, int mode, int ndigits, int *decpt, int *sign, char **rve)
+ (double dd, int mode, int ndigits, int *decpt, int *sign, char **rve)
#endif
{
/* Arguments ndigits, decpt, sign are similar to those
@@ -2687,7 +2681,8 @@ dtoa
ULong x;
#endif
Bigint *b, *b1, *delta, *mlo, *mhi, *S;
- double d2, ds, eps;
+ double ds;
+ U d2, eps;
char *s, *s0;
#ifdef Honor_FLT_ROUNDS
int rounding;
@@ -2695,6 +2690,8 @@ dtoa
#ifdef SET_INEXACT
int inexact, oldinexact;
#endif
+ U d;
+ dval(d) = dd;
/* In mode 2 and 3 we bias rounding up when there are ties. */
bias_round_up = mode == 2 || mode == 3;
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