Add definition pg_attribute_aligned() for MSVC

Visual Studio 2015+ has support for a macro to control the alignement of
structures as of __declspec(align(#)), and this commit adds a definition
of pg_attribute_aligned() based on that.  It happens that this was
already used in the implementation of atomics for MSVC.  Note that there
is still no definition fo pg_attribute_packed(), so this does not impact
itemptr.h.

Author: James Coleman
Discussion: https://postgr.es/m/CAAaqYe-HbtZvR3msoMtk+hYW2S0e0OapzMW8icSMYTMA+mN8Aw@mail.gmail.com
This commit is contained in:
Michael Paquier 2022-09-21 10:11:23 +09:00
parent 1c27d16e6e
commit ec3c9cc202
4 changed files with 16 additions and 1 deletions

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@ -139,6 +139,8 @@ if test x"$pgac_cv__128bit_int" = xyes ; then
/* This must match the corresponding code in c.h: */
#if defined(__GNUC__) || defined(__SUNPRO_C) || defined(__IBMC__)
#define pg_attribute_aligned(a) __attribute__((aligned(a)))
#elif defined(_MSC_VER)
#define pg_attribute_aligned(a) __declspec(align(a))
#endif
typedef __int128 int128a
#if defined(pg_attribute_aligned)

2
configure vendored
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@ -17462,6 +17462,8 @@ else
/* This must match the corresponding code in c.h: */
#if defined(__GNUC__) || defined(__SUNPRO_C) || defined(__IBMC__)
#define pg_attribute_aligned(a) __attribute__((aligned(a)))
#elif defined(_MSC_VER)
#define pg_attribute_aligned(a) __declspec(align(a))
#endif
typedef __int128 int128a
#if defined(pg_attribute_aligned)

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@ -181,6 +181,17 @@
#define pg_attribute_noreturn() __attribute__((noreturn))
#define pg_attribute_packed() __attribute__((packed))
#define HAVE_PG_ATTRIBUTE_NORETURN 1
#elif defined(_MSC_VER)
/*
* MSVC supports aligned. noreturn is also possible but in MSVC it is
* declared before the definition while pg_attribute_noreturn() macro
* is currently used after the definition.
*
* Packing is also possible but only by wrapping the entire struct definition
* which doesn't fit into our current macro declarations.
*/
#define pg_attribute_aligned(a) __declspec(align(a))
#define pg_attribute_noreturn()
#else
/*
* NB: aligned and packed are not given default definitions because they

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@ -39,7 +39,7 @@ typedef struct pg_atomic_uint32
} pg_atomic_uint32;
#define PG_HAVE_ATOMIC_U64_SUPPORT
typedef struct __declspec(align(8)) pg_atomic_uint64
typedef struct pg_attribute_aligned(8) pg_atomic_uint64
{
volatile uint64 value;
} pg_atomic_uint64;