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Work around -fsanitize=integer issues

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Integer sanitizer is flagging unsigned integer overflow in several
functions in pugixml; unsigned integer overflow is well defined but it
may not necessarily be intended.

Apart from hash functions, both string_to_integer and integer_to_string
use unsigned overflow - string_to_integer uses it to perform
two-complement negation so that the bulk of the operation can run using
unsigned integers. This makes it possible to simplify overflow checking.
Similarly integer_to_string negates the number before generating a
decimal representation, but negating is impossible without unsigned
overflow or special-casing certain integer limits.

For now just silence the integer overflow using a special attribute;
also move unsigned overflow into string_to_integer from get_value_* so
that we have fewer functions marked with the attribute.

Fixes #133.
This commit is contained in:
Arseny Kapoulkine 2017-04-03 23:16:49 -07:00
parent 24d1a4562b
commit 38edf255ae
1 changed files with 21 additions and 9 deletions
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30
src/pugixml.cpp
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@ -97,6 +97,17 @@
# define PUGI__DMC_VOLATILE
#endif
// Integer sanitizer workaround
#ifdef __has_attribute
# if __has_attribute(no_sanitize)
# define PUGI__UNSIGNED_OVERFLOW __attribute__((no_sanitize("unsigned-integer-overflow")))
# else
# define PUGI__UNSIGNED_OVERFLOW
# endif
#else
# define PUGI__UNSIGNED_OVERFLOW
#endif
// Borland C++ bug workaround for not defining ::memcpy depending on header include order (can't always use std::memcpy because some compilers don't have it at all)
#if defined(__BORLANDC__) && !defined(__MEM_H_USING_LIST)
using std::memcpy;
@ -346,7 +357,7 @@ PUGI__NS_BEGIN
return 0;
}
static unsigned int hash(const void* key)
static PUGI__UNSIGNED_OVERFLOW unsigned int hash(const void* key)
{
unsigned int h = static_cast<unsigned int>(reinterpret_cast<uintptr_t>(key));
@ -4439,7 +4450,7 @@ PUGI__NS_BEGIN
}
// get value with conversion functions
template <typename U> PUGI__FN U string_to_integer(const char_t* value, U minneg, U maxpos)
template <typename U> PUGI__FN PUGI__UNSIGNED_OVERFLOW U string_to_integer(const char_t* value, U minv, U maxv)
{
U result = 0;
const char_t* s = value;
@ -4512,18 +4523,18 @@ PUGI__NS_BEGIN
{
// Workaround for crayc++ CC-3059: Expected no overflow in routine.
#ifdef _CRAYC
return (overflow || result > minneg) ? ~minneg + 1 : ~result + 1;
return (overflow || result > ~minv + 1) ? minv : ~result + 1;
#else
return (overflow || result > minneg) ? 0 - minneg : 0 - result;
return (overflow || result > 0 - minv) ? minv : 0 - result;
#endif
}
else
return (overflow || result > maxpos) ? maxpos : result;
return (overflow || result > maxv) ? maxv : result;
}
PUGI__FN int get_value_int(const char_t* value)
{
return string_to_integer<unsigned int>(value, 0 - static_cast<unsigned int>(INT_MIN), INT_MAX);
return string_to_integer<unsigned int>(value, static_cast<unsigned int>(INT_MIN), INT_MAX);
}
PUGI__FN unsigned int get_value_uint(const char_t* value)
@ -4561,7 +4572,7 @@ PUGI__NS_BEGIN
#ifdef PUGIXML_HAS_LONG_LONG
PUGI__FN long long get_value_llong(const char_t* value)
{
return string_to_integer<unsigned long long>(value, 0 - static_cast<unsigned long long>(LLONG_MIN), LLONG_MAX);
return string_to_integer<unsigned long long>(value, static_cast<unsigned long long>(LLONG_MIN), LLONG_MAX);
}
PUGI__FN unsigned long long get_value_ullong(const char_t* value)
@ -4570,7 +4581,7 @@ PUGI__NS_BEGIN
}
#endif
template <typename U> PUGI__FN char_t* integer_to_string(char_t* begin, char_t* end, U value, bool negative)
template <typename U> PUGI__FN PUGI__UNSIGNED_OVERFLOW char_t* integer_to_string(char_t* begin, char_t* end, U value, bool negative)
{
char_t* result = end - 1;
U rest = negative ? 0 - value : value;
@ -8404,7 +8415,7 @@ PUGI__NS_BEGIN
static const xpath_node_set dummy_node_set;
PUGI__FN unsigned int hash_string(const char_t* str)
PUGI__FN PUGI__UNSIGNED_OVERFLOW unsigned int hash_string(const char_t* str)
{
// Jenkins one-at-a-time hash (http://en.wikipedia.org/wiki/Jenkins_hash_function#one-at-a-time)
unsigned int result = 0;
@ -12580,6 +12591,7 @@ namespace pugi
#undef PUGI__UNLIKELY
#undef PUGI__STATIC_ASSERT
#undef PUGI__DMC_VOLATILE
#undef PUGI__UNSIGNED_OVERFLOW
#undef PUGI__MSVC_CRT_VERSION
#undef PUGI__NS_BEGIN
#undef PUGI__NS_END