[lttng-dev] [PATCH v5 babeltrace 1/1] Fix: bitfield: shift undefined/implementation defined behaviors
Simon Marchi
simark at simark.ca
Tue May 14 12:31:15 EDT 2019
On 2019-05-13 4:20 p.m., Mathieu Desnoyers wrote:
> bitfield.h uses the left shift operator with a left operand which
> may be negative. The C99 standard states that shifting a negative
> value is undefined.
>
> When building with -Wshift-negative-value, we get this gcc warning:
>
> In file included from /home/smarchi/src/babeltrace/include/babeltrace/ctfser-internal.h:44:0,
> from /home/smarchi/src/babeltrace/ctfser/ctfser.c:42:
> /home/smarchi/src/babeltrace/include/babeltrace/ctfser-internal.h: In function ‘bt_ctfser_write_unsigned_int’:
> /home/smarchi/src/babeltrace/include/babeltrace/bitfield-internal.h:116:24: error: left shift of negative value [-Werror=shift-negative-value]
> mask = ~((~(type) 0) << (__start % ts)); \
> ^
> /home/smarchi/src/babeltrace/include/babeltrace/bitfield-internal.h:222:2: note: in expansion of macro ‘_bt_bitfield_write_le’
> _bt_bitfield_write_le(ptr, type, _start, _length, _v)
> ^~~~~~~~~~~~~~~~~~~~~
> /home/smarchi/src/babeltrace/include/babeltrace/ctfser-internal.h:418:3: note: in expansion of macro ‘bt_bitfield_write_le’
> bt_bitfield_write_le(mmap_align_addr(ctfser->base_mma) +
> ^~~~~~~~~~~~~~~~~~~~
>
> This boils down to the fact that the expression ~((uint8_t)0) has type
> "signed int", which is used as an operand of the left shift. This is due
> to the integer promotion rules of C99 (6.3.3.1):
>
> If an int can represent all values of the original type, the value is
> converted to an int; otherwise, it is converted to an unsigned int.
> These are called the integer promotions. All other types are unchanged
> by the integer promotions.
>
> We also need to cast the result explicitly into the left hand
> side type to deal with:
>
> warning: large integer implicitly truncated to unsigned type [-Woverflow]
>
> The C99 standard states that a right shift has implementation-defined
> behavior when shifting a signed negative value. Add a preprocessor check
> that the compiler provides the expected behavior, else provide an
> alternative implementation which guarantees the intended behavior.
>
> A preprocessor check is also added to ensure that the compiler
> representation for signed values is two's complement, which is expected
> by this header.
>
> Document that this header strictly respects the C89 standard, with
> the exception of its use of __typeof__.
>
> Adapt use of _bt_piecewise_lshift in plugins/text/pretty/print.c
> to the new API.
>
> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
> Change-Id: I658bc5cde68b118dd51740ec0cc370f2217b0e14
> ---
> Changes since v1:
> - Generate compile-time error if the type argument passed to
> _bt_unsigned_cast() is larger than sizeof(uint64_t), this
> allows removing _bt_check_max_64bit,
> - Introduce _br_fill_mask, which replaces _bt_bitwise_not,
> - Clarify _bt_unsigned_cast comment,
> - Expand explanation of the issue within the patch commit message.
>
> Changes since v2:
> - Fix unwanted sign extension when generating masks,
> - Introduce macro helpers to clarify code:
> - _bt_cast_value_to_unsigned()
> - _bt_cast_value_to_unsigned_type(),
> - _bt_make_mask_complement(),
> - _bt_make_mask().
>
> Changes since v3:
> - Fix additional left shift undefined behavior. Identified with
> -fsanitize=undefined.
> - Create fallback for right shift implementation-defined behavior
> if the behavior is found not to be as intended. Detect the behavior
> with a preprocessor check.
> - Ensure that the compiler represents signed types with two's complement
> with a preprocessor check.
> - Add _bt_rshift() and _bt_lshift() shift helpers to take care of
> C99's undefined behaviors related to shifting signed types.
> - Remove statement-expressions to allow building with -std=c99.
> - Use __typeof__ instead of typeof to allow building with -std=c99.
> Strictly speaking, the use of __typeof__ is specific to the compiler.
> Therefore, porting to a strict ansi C compiler would require removing
> those __typeof__.
> - Remove use of gnu extension: replace (a ? : b) expressions by (a ? a :
> b) to please compiling with -std=c99 -Wpedantic.
>
> Changes since v4:
> - Document strict C89 compliance, except for use of __typeof__
> compiler-specific extension.
> - Adapt use of _bt_piecewise_lshift in plugins/text/pretty/print.c
> to the new API.
> ---
> include/babeltrace/bitfield-internal.h | 298 +++++++++++++++++++++------------
> plugins/text/pretty/print.c | 4 +-
> 2 files changed, 195 insertions(+), 107 deletions(-)
>
> diff --git a/include/babeltrace/bitfield-internal.h b/include/babeltrace/bitfield-internal.h
> index c5d5eccd..f108a79c 100644
> --- a/include/babeltrace/bitfield-internal.h
> +++ b/include/babeltrace/bitfield-internal.h
> @@ -2,7 +2,7 @@
> #define _BABELTRACE_BITFIELD_H
>
> /*
> - * Copyright 2010 - Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
> + * Copyright 2010-2019 - Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
> *
> * Permission is hereby granted, free of charge, to any person obtaining a copy
> * of this software and associated documentation files (the "Software"), to deal
> @@ -27,49 +27,145 @@
> #include <babeltrace/compat/limits-internal.h> /* C99 5.2.4.2 Numerical limits */
> #include <babeltrace/endian-internal.h> /* Non-standard BIG_ENDIAN, LITTLE_ENDIAN, BYTE_ORDER */
>
> -/* We can't shift a int from 32 bit, >> 32 and << 32 on int is undefined */
> -#define _bt_piecewise_rshift(_v, _shift) \
> -({ \
> - typeof(_v) ___v = (_v); \
> - typeof(_shift) ___shift = (_shift); \
> - unsigned long sb = (___shift) / (sizeof(___v) * CHAR_BIT - 1); \
> - unsigned long final = (___shift) % (sizeof(___v) * CHAR_BIT - 1); \
> - \
> - for (; sb; sb--) \
> - ___v >>= sizeof(___v) * CHAR_BIT - 1; \
> - ___v >>= final; \
> -})
> +/*
> + * This header strictly follows the C89 standard, except for use of the
> + * compiler-specific __typeof__.
> + */
>
> -#define _bt_piecewise_lshift(_v, _shift) \
> -({ \
> - typeof(_v) ___v = (_v); \
> - typeof(_shift) ___shift = (_shift); \
> - unsigned long sb = (___shift) / (sizeof(___v) * CHAR_BIT - 1); \
> - unsigned long final = (___shift) % (sizeof(___v) * CHAR_BIT - 1); \
> - \
> - for (; sb; sb--) \
> - ___v <<= sizeof(___v) * CHAR_BIT - 1; \
> - ___v <<= final; \
> -})
> +/*
> + * This bitfield header requires the compiler representation of signed
> + * integers to be two's complement.
> + */
> +#if (-1 != ~0)
> +#error "bitfield.h requires the compiler representation of signed integers to be two's complement."
> +#endif
>
> #define _bt_is_signed_type(type) ((type) -1 < (type) 0)
>
> /*
> - * NOTE: The cast to (uint64_t) below ensures that we're not casting a
> - * negative value, which is undefined in C. However, this limits the
> - * maximum type size of `type` and `v` to 64-bit. The
> - * _bt_check_max_64bit() is used to check that the users of this header
> - * do not use types with a size greater than 64-bit.
> + * Produce a build-time error if the condition `cond` is non-zero.
> + * Evaluates as a size_t expression.
> + */
> +#define _BT_BUILD_ASSERT(cond) \
> + sizeof(struct { int f:(2 * !!(cond) - 1); })
> +
> +/*
> + * Cast value `v` to an unsigned integer of the same size as `v`.
> + */
> +#define _bt_cast_value_to_unsigned(v) \
> + (sizeof(v) == sizeof(uint8_t) ? (uint8_t) (v) : \
> + sizeof(v) == sizeof(uint16_t) ? (uint16_t) (v) : \
> + sizeof(v) == sizeof(uint32_t) ? (uint32_t) (v) : \
> + sizeof(v) == sizeof(uint64_t) ? (uint64_t) (v) : \
> + _BT_BUILD_ASSERT(sizeof(v) <= sizeof(uint64_t)))
> +
> +/*
> + * Cast value `v` to an unsigned integer type of the size of type `type`
> + * *without* sign-extension.
> + *
> + * The unsigned cast ensures that we're not shifting a negative value,
> + * which is undefined in C. However, this limits the maximum type size
> + * of `type` to 64-bit. Generate a compile-time error if the size of
> + * `type` is larger than 64-bit.
> */
> -#define _bt_unsigned_cast(type, v) \
> -({ \
> - (sizeof(v) < sizeof(type)) ? \
> - ((type) (v)) & ((type) (~(~(uint64_t) 0 << (sizeof(v) * CHAR_BIT)))) : \
> - (type) (v); \
> -})
> +#define _bt_cast_value_to_unsigned_type(type, v) \
> + (sizeof(type) == sizeof(uint8_t) ? \
> + (uint8_t) _bt_cast_value_to_unsigned(v) : \
> + sizeof(type) == sizeof(uint16_t) ? \
> + (uint16_t) _bt_cast_value_to_unsigned(v) : \
> + sizeof(type) == sizeof(uint32_t) ? \
> + (uint32_t) _bt_cast_value_to_unsigned(v) : \
> + sizeof(type) == sizeof(uint64_t) ? \
> + (uint64_t) _bt_cast_value_to_unsigned(v) : \
> + _BT_BUILD_ASSERT(sizeof(v) <= sizeof(uint64_t)))
>
> -#define _bt_check_max_64bit(type) \
> - char _max_64bit_assertion[sizeof(type) <= sizeof(uint64_t) ? 1 : -1] __attribute__((unused))
> +/*
> + * _bt_fill_mask evaluates to a "type" integer with all bits set.
> + */
> +#define _bt_fill_mask(type) ((type) ~(type) 0)
> +
> +/*
> + * Left shift a value `v` of `shift` bits.
> + *
> + * The type of `v` can be signed or unsigned integer.
> + * The value of `shift` must be less than the size of `v` (in bits),
> + * otherwise the behavior is undefined.
> + * Evaluates to the result of the shift operation.
> + *
> + * According to the C99 standard, left shift of a left hand-side signed
> + * type is undefined if it has a negative value or if the result cannot
> + * be represented in the result type. This bitfield header discards the
> + * bits that are left-shifted beyond the result type representation,
> + * which is the behavior of an unsigned type left shift operation.
> + * Therefore, always perform left shift on an unsigned type.
> + */
> +#define _bt_lshift(v, shift) \
> + ((__typeof__(v)) (_bt_cast_value_to_unsigned(v) << (shift)))
> +
> +/*
> + * Generate a mask of type `type` with the `length` least significant bits
> + * cleared, and the most significant bits set.
> + */
> +#define _bt_make_mask_complement(type, length) \
> + _bt_lshift(_bt_fill_mask(type), length)
> +
> +/*
> + * Generate a mask of type `type` with the `length` least significant bits
> + * set, and the most significant bits cleared.
> + */
> +#define _bt_make_mask(type, length) \
> + ((type) ~_bt_make_mask_complement(type, length))
> +
> +/*
> + * Right shift a value `v` of `shift` bits.
> + *
> + * The type of `v` can be signed or unsigned integer.
> + * The value of `shift` must be less than the size of `v` (in bits),
> + * otherwise the behavior is undefined.
> + * Evaluates to the result of the shift operation.
> + *
> + * According to the C99 standard, right shift of a left hand-side signed
> + * type which has a negative value is implementation defined. This
> + * bitfield header relies on the right shift implementation carrying the
> + * sign bit. If the compiler implementation has a different behavior,
> + * emulate carrying the sign bit.
> + */
> +#if ((-1 >> 1) == -1)
> +#define _bt_rshift(v, shift) ((v) >> (shift))
> +#else
> +#define _bt_rshift(v, shift) \
> + ((__typeof__(v)) ((_bt_cast_value_to_unsigned(v) >> (shift)) | \
> + ((v) < 0 ? _bt_make_mask_complement(__typeof__(v), \
> + sizeof(v) * CHAR_BIT - (shift)) : 0)))
> +#endif
> +
> +/*
> + * Right shift a signed or unsigned integer with `_shift` value being an
> + * arbitrary number of bits. `_v` is modified by this macro.
> + */
> +#define _bt_piecewise_rshift(_v, _shift) \
> +do { \
> + unsigned long _sb = (_shift) / (sizeof(_v) * CHAR_BIT - 1); \
> + unsigned long _final = (_shift) % (sizeof(_v) * CHAR_BIT - 1); \
> + \
> + for (; _sb; _sb--) \
> + (_v) = _bt_rshift(_v, sizeof(_v) * CHAR_BIT - 1); \
> + (_v) = _bt_rshift(_v, _final); \
> +} while (0)
> +
> +/*
> + * Left shift a signed or unsigned integer with `_shift` value being an
> + * arbitrary number of bits. `_v` is modified by this macro.
> + */
> +#define _bt_piecewise_lshift(_v, _shift) \
> +do { \
> + unsigned long _sb = (_shift) / (sizeof(_v) * CHAR_BIT - 1); \
> + unsigned long _final = (_shift) % (sizeof(_v) * CHAR_BIT - 1); \
> + \
> + for (; _sb; _sb--) \
> + (_v) = _bt_lshift(_v, sizeof(_v) * CHAR_BIT - 1); \
> + (_v) = _bt_lshift(_v, _final); \
> +} while (0)
>
> /*
> * bt_bitfield_write - write integer to a bitfield in native endianness
> @@ -91,7 +187,7 @@
>
> #define _bt_bitfield_write_le(_ptr, type, _start, _length, _v) \
> do { \
> - typeof(_v) __v = (_v); \
> + __typeof__(_v) __v = (_v); \
> type *__ptr = (void *) (_ptr); \
> unsigned long __start = (_start), __length = (_length); \
> type mask, cmask; \
> @@ -108,15 +204,15 @@ do { \
> \
> /* Trim v high bits */ \
> if (__length < sizeof(__v) * CHAR_BIT) \
> - __v &= ~((~(typeof(__v)) 0) << __length); \
> + __v &= _bt_make_mask(__typeof__(__v), __length); \
> \
> /* We can now append v with a simple "or", shift it piece-wise */ \
> this_unit = start_unit; \
> if (start_unit == end_unit - 1) { \
> - mask = ~((~(type) 0) << (__start % ts)); \
> + mask = _bt_make_mask(type, __start % ts); \
> if (end % ts) \
> - mask |= (~(type) 0) << (end % ts); \
> - cmask = (type) __v << (__start % ts); \
> + mask |= _bt_make_mask_complement(type, end % ts); \
> + cmask = _bt_lshift((type) (__v), __start % ts); \
> cmask &= ~mask; \
> __ptr[this_unit] &= mask; \
> __ptr[this_unit] |= cmask; \
> @@ -124,22 +220,22 @@ do { \
> } \
> if (__start % ts) { \
> cshift = __start % ts; \
> - mask = ~((~(type) 0) << cshift); \
> - cmask = (type) __v << cshift; \
> + mask = _bt_make_mask(type, cshift); \
> + cmask = _bt_lshift((type) (__v), cshift); \
> cmask &= ~mask; \
> __ptr[this_unit] &= mask; \
> __ptr[this_unit] |= cmask; \
> - __v = _bt_piecewise_rshift(__v, ts - cshift); \
> + _bt_piecewise_rshift(__v, ts - cshift); \
> __start += ts - cshift; \
> this_unit++; \
> } \
> for (; this_unit < end_unit - 1; this_unit++) { \
> __ptr[this_unit] = (type) __v; \
> - __v = _bt_piecewise_rshift(__v, ts); \
> + _bt_piecewise_rshift(__v, ts); \
> __start += ts; \
> } \
> if (end % ts) { \
> - mask = (~(type) 0) << (end % ts); \
> + mask = _bt_make_mask_complement(type, end % ts); \
> cmask = (type) __v; \
> cmask &= ~mask; \
> __ptr[this_unit] &= mask; \
> @@ -150,7 +246,7 @@ do { \
>
> #define _bt_bitfield_write_be(_ptr, type, _start, _length, _v) \
> do { \
> - typeof(_v) __v = (_v); \
> + __typeof__(_v) __v = (_v); \
> type *__ptr = (void *) (_ptr); \
> unsigned long __start = (_start), __length = (_length); \
> type mask, cmask; \
> @@ -167,15 +263,15 @@ do { \
> \
> /* Trim v high bits */ \
> if (__length < sizeof(__v) * CHAR_BIT) \
> - __v &= ~((~(typeof(__v)) 0) << __length); \
> + __v &= _bt_make_mask(__typeof__(__v), __length); \
> \
> /* We can now append v with a simple "or", shift it piece-wise */ \
> this_unit = end_unit - 1; \
> if (start_unit == end_unit - 1) { \
> - mask = ~((~(type) 0) << ((ts - (end % ts)) % ts)); \
> + mask = _bt_make_mask(type, (ts - (end % ts)) % ts); \
> if (__start % ts) \
> - mask |= (~((type) 0)) << (ts - (__start % ts)); \
> - cmask = (type) __v << ((ts - (end % ts)) % ts); \
> + mask |= _bt_make_mask_complement(type, ts - (__start % ts)); \
> + cmask = _bt_lshift((type) (__v), (ts - (end % ts)) % ts); \
> cmask &= ~mask; \
> __ptr[this_unit] &= mask; \
> __ptr[this_unit] |= cmask; \
> @@ -183,22 +279,22 @@ do { \
> } \
> if (end % ts) { \
> cshift = end % ts; \
> - mask = ~((~(type) 0) << (ts - cshift)); \
> - cmask = (type) __v << (ts - cshift); \
> + mask = _bt_make_mask(type, ts - cshift); \
> + cmask = _bt_lshift((type) (__v), ts - cshift); \
> cmask &= ~mask; \
> __ptr[this_unit] &= mask; \
> __ptr[this_unit] |= cmask; \
> - __v = _bt_piecewise_rshift(__v, cshift); \
> + _bt_piecewise_rshift(__v, cshift); \
> end -= cshift; \
> this_unit--; \
> } \
> for (; (long) this_unit >= (long) start_unit + 1; this_unit--) { \
> __ptr[this_unit] = (type) __v; \
> - __v = _bt_piecewise_rshift(__v, ts); \
> + _bt_piecewise_rshift(__v, ts); \
> end -= ts; \
> } \
> if (__start % ts) { \
> - mask = (~(type) 0) << (ts - (__start % ts)); \
> + mask = _bt_make_mask(type, ts - (__start % ts)); \
> cmask = (type) __v; \
> cmask &= ~mask; \
> __ptr[this_unit] &= mask; \
> @@ -243,8 +339,8 @@ do { \
>
> #define _bt_bitfield_read_le(_ptr, type, _start, _length, _vptr) \
> do { \
> - typeof(*(_vptr)) *__vptr = (_vptr); \
> - typeof(*__vptr) __v; \
> + __typeof__(*(_vptr)) *__vptr = (_vptr); \
> + __typeof__(*__vptr) __v; \
> type *__ptr = (void *) (_ptr); \
> unsigned long __start = (_start), __length = (_length); \
> type mask, cmask; \
> @@ -252,10 +348,6 @@ do { \
> unsigned long start_unit, end_unit, this_unit; \
> unsigned long end, cshift; /* cshift is "complement shift" */ \
> \
> - { _bt_check_max_64bit(type); } \
> - { _bt_check_max_64bit(typeof(*_vptr)); } \
> - { _bt_check_max_64bit(typeof(*_ptr)); } \
> - \
> if (!__length) { \
> *__vptr = 0; \
> break; \
> @@ -266,56 +358,56 @@ do { \
> end_unit = (end + (ts - 1)) / ts; \
> \
> this_unit = end_unit - 1; \
> - if (_bt_is_signed_type(typeof(__v)) \
> - && (__ptr[this_unit] & ((type) 1 << ((end % ts ? : ts) - 1)))) \
> - __v = ~(typeof(__v)) 0; \
> + if (_bt_is_signed_type(__typeof__(__v)) \
> + && (__ptr[this_unit] & _bt_lshift((type) 1, (end % ts ? end % ts : ts) - 1))) \
> + __v = ~(__typeof__(__v)) 0; \
> else \
> __v = 0; \
> if (start_unit == end_unit - 1) { \
> cmask = __ptr[this_unit]; \
> - cmask >>= (__start % ts); \
> + cmask = _bt_rshift(cmask, __start % ts); \
> if ((end - __start) % ts) { \
> - mask = ~((~(type) 0) << (end - __start)); \
> + mask = _bt_make_mask(type, end - __start); \
> cmask &= mask; \
> } \
> - __v = _bt_piecewise_lshift(__v, end - __start); \
> - __v |= _bt_unsigned_cast(typeof(__v), cmask); \
> + _bt_piecewise_lshift(__v, end - __start); \
> + __v |= _bt_cast_value_to_unsigned_type(__typeof__(__v), cmask); \
> *__vptr = __v; \
> break; \
> } \
> if (end % ts) { \
> cshift = end % ts; \
> - mask = ~((~(type) 0) << cshift); \
> + mask = _bt_make_mask(type, cshift); \
> cmask = __ptr[this_unit]; \
> cmask &= mask; \
> - __v = _bt_piecewise_lshift(__v, cshift); \
> - __v |= _bt_unsigned_cast(typeof(__v), cmask); \
> + _bt_piecewise_lshift(__v, cshift); \
> + __v |= _bt_cast_value_to_unsigned_type(__typeof__(__v), cmask); \
> end -= cshift; \
> this_unit--; \
> } \
> for (; (long) this_unit >= (long) start_unit + 1; this_unit--) { \
> - __v = _bt_piecewise_lshift(__v, ts); \
> - __v |= _bt_unsigned_cast(typeof(__v), __ptr[this_unit]);\
> + _bt_piecewise_lshift(__v, ts); \
> + __v |= _bt_cast_value_to_unsigned_type(__typeof__(__v), __ptr[this_unit]); \
> end -= ts; \
> } \
> if (__start % ts) { \
> - mask = ~((~(type) 0) << (ts - (__start % ts))); \
> + mask = _bt_make_mask(type, ts - (__start % ts)); \
> cmask = __ptr[this_unit]; \
> - cmask >>= (__start % ts); \
> + cmask = _bt_rshift(cmask, __start % ts); \
> cmask &= mask; \
> - __v = _bt_piecewise_lshift(__v, ts - (__start % ts)); \
> - __v |= _bt_unsigned_cast(typeof(__v), cmask); \
> + _bt_piecewise_lshift(__v, ts - (__start % ts)); \
> + __v |= _bt_cast_value_to_unsigned_type(__typeof__(__v), cmask); \
> } else { \
> - __v = _bt_piecewise_lshift(__v, ts); \
> - __v |= _bt_unsigned_cast(typeof(__v), __ptr[this_unit]);\
> + _bt_piecewise_lshift(__v, ts); \
> + __v |= _bt_cast_value_to_unsigned_type(__typeof__(__v), __ptr[this_unit]); \
> } \
> *__vptr = __v; \
> } while (0)
>
> #define _bt_bitfield_read_be(_ptr, type, _start, _length, _vptr) \
> do { \
> - typeof(*(_vptr)) *__vptr = (_vptr); \
> - typeof(*__vptr) __v; \
> + __typeof__(*(_vptr)) *__vptr = (_vptr); \
> + __typeof__(*__vptr) __v; \
> type *__ptr = (void *) (_ptr); \
> unsigned long __start = (_start), __length = (_length); \
> type mask, cmask; \
> @@ -323,10 +415,6 @@ do { \
> unsigned long start_unit, end_unit, this_unit; \
> unsigned long end, cshift; /* cshift is "complement shift" */ \
> \
> - { _bt_check_max_64bit(type); } \
> - { _bt_check_max_64bit(typeof(*_vptr)); } \
> - { _bt_check_max_64bit(typeof(*_ptr)); } \
> - \
> if (!__length) { \
> *__vptr = 0; \
> break; \
> @@ -337,48 +425,48 @@ do { \
> end_unit = (end + (ts - 1)) / ts; \
> \
> this_unit = start_unit; \
> - if (_bt_is_signed_type(typeof(__v)) \
> - && (__ptr[this_unit] & ((type) 1 << (ts - (__start % ts) - 1)))) \
> - __v = ~(typeof(__v)) 0; \
> + if (_bt_is_signed_type(__typeof__(__v)) \
> + && (__ptr[this_unit] & _bt_lshift((type) 1, ts - (__start % ts) - 1))) \
> + __v = ~(__typeof__(__v)) 0; \
> else \
> __v = 0; \
> if (start_unit == end_unit - 1) { \
> cmask = __ptr[this_unit]; \
> - cmask >>= (ts - (end % ts)) % ts; \
> + cmask = _bt_rshift(cmask, (ts - (end % ts)) % ts); \
> if ((end - __start) % ts) { \
> - mask = ~((~(type) 0) << (end - __start)); \
> + mask = _bt_make_mask(type, end - __start); \
> cmask &= mask; \
> } \
> - __v = _bt_piecewise_lshift(__v, end - __start); \
> - __v |= _bt_unsigned_cast(typeof(__v), cmask); \
> + _bt_piecewise_lshift(__v, end - __start); \
> + __v |= _bt_cast_value_to_unsigned_type(__typeof__(__v), cmask); \
> *__vptr = __v; \
> break; \
> } \
> if (__start % ts) { \
> cshift = __start % ts; \
> - mask = ~((~(type) 0) << (ts - cshift)); \
> + mask = _bt_make_mask(type, ts - cshift); \
> cmask = __ptr[this_unit]; \
> cmask &= mask; \
> - __v = _bt_piecewise_lshift(__v, ts - cshift); \
> - __v |= _bt_unsigned_cast(typeof(__v), cmask); \
> + _bt_piecewise_lshift(__v, ts - cshift); \
> + __v |= _bt_cast_value_to_unsigned_type(__typeof__(__v), cmask); \
> __start += ts - cshift; \
> this_unit++; \
> } \
> for (; this_unit < end_unit - 1; this_unit++) { \
> - __v = _bt_piecewise_lshift(__v, ts); \
> - __v |= _bt_unsigned_cast(typeof(__v), __ptr[this_unit]);\
> + _bt_piecewise_lshift(__v, ts); \
> + __v |= _bt_cast_value_to_unsigned_type(__typeof__(__v), __ptr[this_unit]); \
> __start += ts; \
> } \
> if (end % ts) { \
> - mask = ~((~(type) 0) << (end % ts)); \
> + mask = _bt_make_mask(type, end % ts); \
> cmask = __ptr[this_unit]; \
> - cmask >>= ts - (end % ts); \
> + cmask = _bt_rshift(cmask, ts - (end % ts)); \
> cmask &= mask; \
> - __v = _bt_piecewise_lshift(__v, end % ts); \
> - __v |= _bt_unsigned_cast(typeof(__v), cmask); \
> + _bt_piecewise_lshift(__v, end % ts); \
> + __v |= _bt_cast_value_to_unsigned_type(__typeof__(__v), cmask); \
> } else { \
> - __v = _bt_piecewise_lshift(__v, ts); \
> - __v |= _bt_unsigned_cast(typeof(__v), __ptr[this_unit]);\
> + _bt_piecewise_lshift(__v, ts); \
> + __v |= _bt_cast_value_to_unsigned_type(__typeof__(__v), __ptr[this_unit]); \
> } \
> *__vptr = __v; \
> } while (0)
> diff --git a/plugins/text/pretty/print.c b/plugins/text/pretty/print.c
> index 95189d5e..2d5ac0d2 100644
> --- a/plugins/text/pretty/print.c
> +++ b/plugins/text/pretty/print.c
> @@ -546,10 +546,10 @@ int print_integer(struct pretty_component *pretty,
>
> len = bt_field_class_integer_get_field_value_range(int_fc);
> g_string_append(pretty->string, "0b");
> - v.u = _bt_piecewise_lshift(v.u, 64 - len);
> + _bt_piecewise_lshift(v.u, 64 - len);
> for (bitnr = 0; bitnr < len; bitnr++) {
> g_string_append_printf(pretty->string, "%u", (v.u & (1ULL << 63)) ? 1 : 0);
> - v.u = _bt_piecewise_lshift(v.u, 1);
> + _bt_piecewise_lshift(v.u, 1);
> }
> break;
> }
>
LGTM.
Simon
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