upstream/postgresql
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2026-07-15 12:51:05 -04:00
Code Issues Projects Releases Packages Wiki Activity Actions

Disable extended alignment uses on older g++

Browse source 
Fix for commit a9bdb63bba.  The previous plan of redefining alignas
didn't work, because it interfered with other C++ header files (e.g.,
LLVM).  So now the new workaround is to just disable the affected
typedefs under the affected compilers.  These are not typically used
in extensions anyway.

Discussion: https://www.postgresql.org/message-id/3119480.1769189606%40sss.pgh.pa.us
This commit is contained in:
Peter Eisentraut 2026-01-26 10:23:14 +01:00
parent d9abd9e105
commit 6ceef9408c
1 changed files with 10 additions and 10 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

20
src/include/c.h
View file

@ -262,16 +262,6 @@
*/ */
#endif #endif
/*
* alignas is buggy in g++ < 9, but the more or less equivalent attribute
* works.
*
* <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89357>
*/
#if defined(__cplusplus) && defined(__GNUC__) && !defined(__clang__) && __GNUC__ < 9
#define alignas(a) __attribute__((aligned(a)))
#endif
/* /*
* Use "pg_attribute_always_inline" in place of "inline" for functions that * Use "pg_attribute_always_inline" in place of "inline" for functions that
* we wish to force inlining of, even when the compiler's heuristics would * we wish to force inlining of, even when the compiler's heuristics would
@ -1123,6 +1113,14 @@ typedef struct PGAlignedBlock
alignas(MAXIMUM_ALIGNOF) char data[BLCKSZ]; alignas(MAXIMUM_ALIGNOF) char data[BLCKSZ];
} PGAlignedBlock; } PGAlignedBlock;
/*
* alignas with extended alignments is buggy in g++ < 9. As a simple
* workaround, we disable these definitions in that case.
*
* <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89357>
*/
#if !(defined(__cplusplus) && defined(__GNUC__) && !defined(__clang__) && __GNUC__ < 9)
/* /*
* Use this to declare a field or local variable holding a page buffer, if that * Use this to declare a field or local variable holding a page buffer, if that
* page might be accessed as a page or passed to an SMgr I/O function. If * page might be accessed as a page or passed to an SMgr I/O function. If
@ -1142,6 +1140,8 @@ typedef struct PGAlignedXLogBlock
alignas(PG_IO_ALIGN_SIZE) char data[XLOG_BLCKSZ]; alignas(PG_IO_ALIGN_SIZE) char data[XLOG_BLCKSZ];
} PGAlignedXLogBlock; } PGAlignedXLogBlock;
#endif /* !(g++ < 9) */
/* msb for char */ /* msb for char */
#define HIGHBIT (0x80) #define HIGHBIT (0x80)
#define IS_HIGHBIT_SET(ch) ((unsigned char)(ch) & HIGHBIT) #define IS_HIGHBIT_SET(ch) ((unsigned char)(ch) & HIGHBIT)