[C++] Fix -Winvalid-offsetof warnings with g++ 4.4

Ref: https://sourceware.org/ml/gdb/2015-12/msg00014.html

Fixes the build in C++ mode with g++ 4.4:

 gdb/btrace.h: In function ‘size_t VEC_btrace_insn_s_embedded_size(int)’:
 gdb/btrace.h:84: error: invalid access to non-static data member ‘VEC_btrace_insn_s::vec’  of NULL object
 gdb/btrace.h:84: error: (perhaps the ‘offsetof’ macro was used incorrectly)
 gdb/btrace.h: In function ‘VEC_btrace_insn_s* VEC_btrace_insn_s_alloc(int)’:
 gdb/btrace.h:84: error: invalid access to non-static data member ‘VEC_btrace_insn_s::vec’  of NULL object
 gdb/btrace.h:84: error: (perhaps the ‘offsetof’ macro was used incorrectly)
 gdb/btrace.h: In function ‘VEC_btrace_insn_s* VEC_btrace_insn_s_copy(VEC_btrace_insn_s*)’:
 gdb/btrace.h:84: error: invalid access to non-static data member ‘VEC_btrace_insn_s::vec’  of NULL object
 gdb/btrace.h:84: error: (perhaps the ‘offsetof’ macro was used incorrectly)
 gdb/btrace.h: In function ‘VEC_btrace_insn_s* VEC_btrace_insn_s_merge(VEC_btrace_insn_s*, VEC_btrace_insn_s*)’:
 gdb/btrace.h:84: error: invalid access to non-static data member ‘VEC_btrace_insn_s::vec’  of NULL object
 gdb/btrace.h:84: error: (perhaps the ‘offsetof’ macro was used incorrectly)
 gdb/btrace.h: In function ‘int VEC_btrace_insn_s_reserve(VEC_btrace_insn_s**, int, const char*, unsigned int)’:
 gdb/btrace.h:84: error: invalid access to non-static data member ‘VEC_btrace_insn_s::vec’  of NULL object
 gdb/btrace.h:84: error: (perhaps the ‘offsetof’ macro was used incorrectly)

gdb/ChangeLog:
2015-12-16  Pedro Alves  <palves@redhat.com>

	* common/vec.h (vec_offset): New macro.
	(DEF_VEC_ALLOC_FUNC_I, DEF_VEC_ALLOC_FUNC_O): Use it instead of
	offsetof.
This commit is contained in:
Pedro Alves 2015-12-16 19:25:32 +00:00
parent 72d98d16ed
commit a4e22a5df6
2 changed files with 40 additions and 10 deletions

View File

@ -1,3 +1,9 @@
2015-12-16 Pedro Alves <palves@redhat.com>
* common/vec.h (vec_offset): New macro.
(DEF_VEC_ALLOC_FUNC_I, DEF_VEC_ALLOC_FUNC_O): Use it instead of
offsetof.
2015-12-11 Don Breazeal <donb@codesourcery.com>
* NEWS: Announce fork and exec event support for target remote.

View File

@ -437,13 +437,23 @@ DEF_VEC_FUNC_O(T) \
DEF_VEC_ALLOC_FUNC_O(T) \
struct vec_swallow_trailing_semi
/* Avoid offsetof (or its usual C implementation) as it triggers
-Winvalid-offsetof warnings with enum_flags types with G++ <= 4.4,
even though those types are memcpyable. This requires allocating a
dummy local VEC in all routines that use this, but that has the
advantage that it only works if T is default constructible, which
is exactly a check we want, to keep C compatibility. */
#define vec_offset(T, VPTR) ((size_t) ((char *) &(VPTR)->vec - (char *) VPTR))
#define DEF_VEC_ALLOC_FUNC_I(T) \
static inline VEC(T) *VEC_OP (T,alloc) \
(int alloc_) \
{ \
VEC(T) dummy; \
\
/* We must request exact size allocation, hence the negation. */ \
return (VEC(T) *) vec_o_reserve (NULL, -alloc_, \
offsetof (VEC(T),vec), sizeof (T)); \
vec_offset (T, &dummy), sizeof (T)); \
} \
\
static inline VEC(T) *VEC_OP (T,copy) (VEC(T) *vec_) \
@ -453,9 +463,11 @@ static inline VEC(T) *VEC_OP (T,copy) (VEC(T) *vec_) \
\
if (len_) \
{ \
VEC(T) dummy; \
\
/* We must request exact size allocation, hence the negation. */ \
new_vec_ = (VEC (T) *) \
vec_o_reserve (NULL, -len_, offsetof (VEC(T),vec), sizeof (T)); \
vec_o_reserve (NULL, -len_, vec_offset (T, &dummy), sizeof (T)); \
\
new_vec_->num = len_; \
memcpy (new_vec_->vec, vec_->vec, sizeof (T) * len_); \
@ -467,12 +479,13 @@ static inline VEC(T) *VEC_OP (T,merge) (VEC(T) *vec1_, VEC(T) *vec2_) \
{ \
if (vec1_ && vec2_) \
{ \
VEC(T) dummy; \
size_t len_ = vec1_->num + vec2_->num; \
VEC (T) *new_vec_ = NULL; \
\
/* We must request exact size allocation, hence the negation. */ \
new_vec_ = (VEC (T) *) \
vec_o_reserve (NULL, -len_, offsetof (VEC(T),vec), sizeof (T)); \
vec_o_reserve (NULL, -len_, vec_offset (T, &dummy), sizeof (T)); \
\
new_vec_->num = len_; \
memcpy (new_vec_->vec, vec1_->vec, sizeof (T) * vec1_->num); \
@ -505,12 +518,13 @@ static inline void VEC_OP (T,cleanup) \
static inline int VEC_OP (T,reserve) \
(VEC(T) **vec_, int alloc_ VEC_ASSERT_DECL) \
{ \
VEC(T) dummy; \
int extend = !VEC_OP (T,space) \
(*vec_, alloc_ < 0 ? -alloc_ : alloc_ VEC_ASSERT_PASS); \
\
if (extend) \
*vec_ = (VEC(T) *) vec_o_reserve (*vec_, alloc_, \
offsetof (VEC(T),vec), sizeof (T)); \
vec_offset (T, &dummy), sizeof (T)); \
\
return extend; \
} \
@ -581,7 +595,9 @@ static inline int VEC_OP (T,iterate) \
static inline size_t VEC_OP (T,embedded_size) \
(int alloc_) \
{ \
return offsetof (VEC(T),vec) + alloc_ * sizeof(T); \
VEC(T) dummy; \
\
return vec_offset (T, &dummy) + alloc_ * sizeof(T); \
} \
\
static inline void VEC_OP (T,embedded_init) \
@ -863,7 +879,9 @@ static inline int VEC_OP (T,iterate) \
static inline size_t VEC_OP (T,embedded_size) \
(int alloc_) \
{ \
return offsetof (VEC(T),vec) + alloc_ * sizeof(T); \
VEC(T) dummy; \
\
return vec_offset (T, &dummy) + alloc_ * sizeof(T); \
} \
\
static inline void VEC_OP (T,embedded_init) \
@ -998,9 +1016,11 @@ static inline unsigned VEC_OP (T,lower_bound) \
static inline VEC(T) *VEC_OP (T,alloc) \
(int alloc_) \
{ \
VEC(T) dummy; \
\
/* We must request exact size allocation, hence the negation. */ \
return (VEC(T) *) vec_o_reserve (NULL, -alloc_, \
offsetof (VEC(T),vec), sizeof (T)); \
vec_offset (T, &dummy), sizeof (T)); \
} \
\
static inline VEC(T) *VEC_OP (T,copy) (VEC(T) *vec_) \
@ -1010,9 +1030,11 @@ static inline VEC(T) *VEC_OP (T,copy) (VEC(T) *vec_) \
\
if (len_) \
{ \
VEC(T) dummy; \
\
/* We must request exact size allocation, hence the negation. */ \
new_vec_ = (VEC (T) *) \
vec_o_reserve (NULL, -len_, offsetof (VEC(T),vec), sizeof (T)); \
vec_o_reserve (NULL, -len_, vec_offset (T, &dummy), sizeof (T)); \
\
new_vec_->num = len_; \
memcpy (new_vec_->vec, vec_->vec, sizeof (T) * len_); \
@ -1024,12 +1046,13 @@ static inline VEC(T) *VEC_OP (T,merge) (VEC(T) *vec1_, VEC(T) *vec2_) \
{ \
if (vec1_ && vec2_) \
{ \
VEC(T) dummy; \
size_t len_ = vec1_->num + vec2_->num; \
VEC (T) *new_vec_ = NULL; \
\
/* We must request exact size allocation, hence the negation. */ \
new_vec_ = (VEC (T) *) \
vec_o_reserve (NULL, -len_, offsetof (VEC(T),vec), sizeof (T)); \
vec_o_reserve (NULL, -len_, vec_offset (T, &dummy), sizeof (T)); \
\
new_vec_->num = len_; \
memcpy (new_vec_->vec, vec1_->vec, sizeof (T) * vec1_->num); \
@ -1062,12 +1085,13 @@ static inline void VEC_OP (T,cleanup) \
static inline int VEC_OP (T,reserve) \
(VEC(T) **vec_, int alloc_ VEC_ASSERT_DECL) \
{ \
VEC(T) dummy; \
int extend = !VEC_OP (T,space) (*vec_, alloc_ < 0 ? -alloc_ : alloc_ \
VEC_ASSERT_PASS); \
\
if (extend) \
*vec_ = (VEC(T) *) \
vec_o_reserve (*vec_, alloc_, offsetof (VEC(T),vec), sizeof (T)); \
vec_o_reserve (*vec_, alloc_, vec_offset (T, &dummy), sizeof (T)); \
\
return extend; \
} \