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authorLukas Larsson <[email protected]>2014-08-04 12:04:45 +0200
committerLukas Larsson <[email protected]>2014-08-08 17:17:18 +0200
commit9d3c22934491afe85fbcf8543ae43fb2eb1ab387 (patch)
tree4cfbd2f87d60b7a143426140984a3ae0b93d9252
parent62081266545df8f5eda8e2043f33055cfe575126 (diff)
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erts: Fix neg int overflow when sint is min size
When INT64_MIN is the value of a Sint64 we have to first cast it to an Uint64 before negating it. Otherwise we get an integer overflow which is undefined behaviour and in gcc 4.9 this results in -0 instead of -9223372036854775808 in gcc 4.8.
-rw-r--r--erts/emulator/beam/big.c18
-rw-r--r--erts/emulator/beam/big.h2
-rw-r--r--erts/emulator/beam/erl_bif_binary.c16
-rw-r--r--erts/emulator/beam/erl_init.c6
4 files changed, 25 insertions, 17 deletions
diff --git a/erts/emulator/beam/big.c b/erts/emulator/beam/big.c
index 41a041eba6..520034d68a 100644
--- a/erts/emulator/beam/big.c
+++ b/erts/emulator/beam/big.c
@@ -274,6 +274,9 @@
_b = _b << _s; \
_vn1 = _b >> H_EXP; \
_vn0 = _b & LO_MASK; \
+ /* Sometimes _s is 0 which triggers undefined behaviour for the \
+ (_a0>>(D_EXP-_s)) shift, but this is ok because the \
+ & -s will make it all to 0 later anyways. */ \
_un32 = (_a1 << _s) | ((_a0>>(D_EXP-_s)) & (-_s >> (D_EXP-1))); \
_un10 = _a0 << _s; \
_un1 = _un10 >> H_EXP; \
@@ -1540,21 +1543,24 @@ Eterm erts_uint64_to_big(Uint64 x, Eterm **hpp)
Eterm erts_sint64_to_big(Sint64 x, Eterm **hpp)
{
Eterm *hp = *hpp;
+ Uint64 ux;
int neg;
- if (x >= 0)
+ if (x >= 0) {
neg = 0;
+ ux = x;
+ }
else {
neg = 1;
- x = -x;
+ ux = -(Uint64)x;
}
#if defined(ARCH_32) || HALFWORD_HEAP
- if (x >= (((Uint64) 1) << 32)) {
+ if (ux >= (((Uint64) 1) << 32)) {
if (neg)
*hp = make_neg_bignum_header(2);
else
*hp = make_pos_bignum_header(2);
- BIG_DIGIT(hp, 0) = (Uint) (x & ((Uint) 0xffffffff));
- BIG_DIGIT(hp, 1) = (Uint) ((x >> 32) & ((Uint) 0xffffffff));
+ BIG_DIGIT(hp, 0) = (Uint) (ux & ((Uint) 0xffffffff));
+ BIG_DIGIT(hp, 1) = (Uint) ((ux >> 32) & ((Uint) 0xffffffff));
*hpp += 3;
}
else
@@ -1564,7 +1570,7 @@ Eterm erts_sint64_to_big(Sint64 x, Eterm **hpp)
*hp = make_neg_bignum_header(1);
else
*hp = make_pos_bignum_header(1);
- BIG_DIGIT(hp, 0) = (Uint) x;
+ BIG_DIGIT(hp, 0) = (Uint) ux;
*hpp += 2;
}
return make_big(hp);
diff --git a/erts/emulator/beam/big.h b/erts/emulator/beam/big.h
index d80111822e..da31876d75 100644
--- a/erts/emulator/beam/big.h
+++ b/erts/emulator/beam/big.h
@@ -101,7 +101,7 @@ typedef Uint dsize_t; /* Vector size type */
#define ERTS_SINT64_HEAP_SIZE(X) \
(IS_SSMALL((X)) \
? 0 \
- : ERTS_UINT64_BIG_HEAP_SIZE__((X) >= 0 ? (X) : -(X)))
+ : ERTS_UINT64_BIG_HEAP_SIZE__((X) >= 0 ? (X) : -(Uint64)(X)))
#define ERTS_UINT64_HEAP_SIZE(X) \
(IS_USMALL(0, (X)) ? 0 : ERTS_UINT64_BIG_HEAP_SIZE__((X)))
diff --git a/erts/emulator/beam/erl_bif_binary.c b/erts/emulator/beam/erl_bif_binary.c
index 7e0e825a0d..3bf78adce7 100644
--- a/erts/emulator/beam/erl_bif_binary.c
+++ b/erts/emulator/beam/erl_bif_binary.c
@@ -1324,9 +1324,9 @@ static int parse_match_opts_list(Eterm l, Eterm bin, Uint *posp, Uint *endp)
goto badarg;
}
if (len < 0) {
- Sint lentmp = -len;
+ Uint lentmp = -(Uint)len;
/* overflow */
- if (lentmp == len || lentmp < 0 || -lentmp != len) {
+ if ((Sint)lentmp < 0) {
goto badarg;
}
len = lentmp;
@@ -1555,9 +1555,9 @@ BIF_RETTYPE erts_binary_part(Process *p, Eterm binary, Eterm epos, Eterm elen)
goto badarg;
}
if (len < 0) {
- Sint lentmp = -len;
+ Uint lentmp = -(Uint)len;
/* overflow */
- if (lentmp == len || lentmp < 0 || -lentmp != len) {
+ if ((Sint)lentmp < 0) {
goto badarg;
}
len = lentmp;
@@ -1644,9 +1644,9 @@ BIF_RETTYPE erts_gc_binary_part(Process *p, Eterm *reg, Eterm live, int range_is
goto badarg;
}
if (len < 0) {
- Sint lentmp = -len;
+ Uint lentmp = -(Uint)len;
/* overflow */
- if (lentmp == len || lentmp < 0 || -lentmp != len) {
+ if ((Sint)lentmp < 0) {
goto badarg;
}
len = lentmp;
@@ -2213,9 +2213,9 @@ static BIF_RETTYPE binary_bin_to_list_common(Process *p,
goto badarg;
}
if (len < 0) {
- Sint lentmp = -len;
+ Uint lentmp = -(Uint)len;
/* overflow */
- if (lentmp == len || lentmp < 0 || -lentmp != len) {
+ if ((Sint)lentmp < 0) {
goto badarg;
}
len = lentmp;
diff --git a/erts/emulator/beam/erl_init.c b/erts/emulator/beam/erl_init.c
index 5e6d812242..88c4006934 100644
--- a/erts/emulator/beam/erl_init.c
+++ b/erts/emulator/beam/erl_init.c
@@ -2066,8 +2066,10 @@ erl_exit_vv(int n, int flush_async, char *fmt, va_list args1, va_list args2)
system_cleanup(flush_async);
save_statistics();
-
- an = abs(n);
+ if (n < 0)
+ an = -(unsigned int)n;
+ else
+ an = n;
if (erts_mtrace_enabled)
erts_mtrace_exit((Uint32) an);