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3691edfab9
We want to support a "noreturn" decoration on more compilers besides
just GCC-compatible ones, but for that we need to move the decoration
in front of the function declaration instead of either behind it or
wherever, which is the current style afforded by GCC-style attributes.
Also rename the macro to "pg_noreturn" to be similar to the C11
standard "noreturn".
pg_noreturn is now supported on all compilers that support C11 (using
_Noreturn), as well as GCC-compatible ones (using __attribute__, as
before), as well as MSVC (using __declspec). (When PostgreSQL
requires C11, the latter two variants can be dropped.)
Now, all supported compilers effectively support pg_noreturn, so the
extra code for !HAVE_PG_ATTRIBUTE_NORETURN can be dropped.
This also fixes a possible problem if third-party code includes
stdnoreturn.h, because then the current definition of
#define pg_attribute_noreturn() __attribute__((noreturn))
would cause an error.
Note that the C standard does not support a noreturn attribute on
function pointer types. So we have to drop these here. There are
only two instances at this time, so it's not a big loss. In one case,
we can make up for it by adding the pg_noreturn to a wrapper function
and adding a pg_unreachable(), in the other case, the latter was
already done before.
Reviewed-by: Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://www.postgresql.org/message-id/flat/pxr5b3z7jmkpenssra5zroxi7qzzp6eswuggokw64axmdixpnk@zbwxuq7gbbcw
177 lines
6.7 KiB
C
177 lines
6.7 KiB
C
/*-------------------------------------------------------------------------
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*
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* memutils_internal.h
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* This file contains declarations for memory allocation utility
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* functions for internal use.
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*
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*
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* Portions Copyright (c) 2022-2025, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* src/include/utils/memutils_internal.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef MEMUTILS_INTERNAL_H
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#define MEMUTILS_INTERNAL_H
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#include "utils/memutils.h"
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/* These functions implement the MemoryContext API for AllocSet context. */
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extern void *AllocSetAlloc(MemoryContext context, Size size, int flags);
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extern void AllocSetFree(void *pointer);
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extern void *AllocSetRealloc(void *pointer, Size size, int flags);
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extern void AllocSetReset(MemoryContext context);
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extern void AllocSetDelete(MemoryContext context);
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extern MemoryContext AllocSetGetChunkContext(void *pointer);
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extern Size AllocSetGetChunkSpace(void *pointer);
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extern bool AllocSetIsEmpty(MemoryContext context);
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extern void AllocSetStats(MemoryContext context,
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MemoryStatsPrintFunc printfunc, void *passthru,
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MemoryContextCounters *totals,
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bool print_to_stderr);
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#ifdef MEMORY_CONTEXT_CHECKING
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extern void AllocSetCheck(MemoryContext context);
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#endif
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/* These functions implement the MemoryContext API for Generation context. */
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extern void *GenerationAlloc(MemoryContext context, Size size, int flags);
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extern void GenerationFree(void *pointer);
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extern void *GenerationRealloc(void *pointer, Size size, int flags);
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extern void GenerationReset(MemoryContext context);
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extern void GenerationDelete(MemoryContext context);
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extern MemoryContext GenerationGetChunkContext(void *pointer);
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extern Size GenerationGetChunkSpace(void *pointer);
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extern bool GenerationIsEmpty(MemoryContext context);
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extern void GenerationStats(MemoryContext context,
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MemoryStatsPrintFunc printfunc, void *passthru,
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MemoryContextCounters *totals,
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bool print_to_stderr);
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#ifdef MEMORY_CONTEXT_CHECKING
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extern void GenerationCheck(MemoryContext context);
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#endif
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/* These functions implement the MemoryContext API for Slab context. */
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extern void *SlabAlloc(MemoryContext context, Size size, int flags);
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extern void SlabFree(void *pointer);
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extern void *SlabRealloc(void *pointer, Size size, int flags);
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extern void SlabReset(MemoryContext context);
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extern void SlabDelete(MemoryContext context);
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extern MemoryContext SlabGetChunkContext(void *pointer);
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extern Size SlabGetChunkSpace(void *pointer);
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extern bool SlabIsEmpty(MemoryContext context);
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extern void SlabStats(MemoryContext context,
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MemoryStatsPrintFunc printfunc, void *passthru,
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MemoryContextCounters *totals,
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bool print_to_stderr);
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#ifdef MEMORY_CONTEXT_CHECKING
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extern void SlabCheck(MemoryContext context);
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#endif
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/*
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* These functions support the implementation of palloc_aligned() and are not
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* part of a fully-fledged MemoryContext type.
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*/
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extern void AlignedAllocFree(void *pointer);
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extern void *AlignedAllocRealloc(void *pointer, Size size, int flags);
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extern MemoryContext AlignedAllocGetChunkContext(void *pointer);
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extern Size AlignedAllocGetChunkSpace(void *pointer);
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/* These functions implement the MemoryContext API for the Bump context. */
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extern void *BumpAlloc(MemoryContext context, Size size, int flags);
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extern void BumpFree(void *pointer);
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extern void *BumpRealloc(void *pointer, Size size, int flags);
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extern void BumpReset(MemoryContext context);
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extern void BumpDelete(MemoryContext context);
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extern MemoryContext BumpGetChunkContext(void *pointer);
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extern Size BumpGetChunkSpace(void *pointer);
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extern bool BumpIsEmpty(MemoryContext context);
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extern void BumpStats(MemoryContext context, MemoryStatsPrintFunc printfunc,
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void *passthru, MemoryContextCounters *totals,
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bool print_to_stderr);
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#ifdef MEMORY_CONTEXT_CHECKING
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extern void BumpCheck(MemoryContext context);
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#endif
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/*
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* How many extra bytes do we need to request in order to ensure that we can
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* align a pointer to 'alignto'. Since palloc'd pointers are already aligned
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* to MAXIMUM_ALIGNOF we can subtract that amount. We also need to make sure
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* there is enough space for the redirection MemoryChunk.
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*/
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#define PallocAlignedExtraBytes(alignto) \
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((alignto) + (sizeof(MemoryChunk) - MAXIMUM_ALIGNOF))
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/*
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* MemoryContextMethodID
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* A unique identifier for each MemoryContext implementation which
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* indicates the index into the mcxt_methods[] array. See mcxt.c.
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*
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* For robust error detection, ensure that MemoryContextMethodID has a value
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* for each possible bit-pattern of MEMORY_CONTEXT_METHODID_MASK, and make
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* dummy entries for unused IDs in the mcxt_methods[] array. We also try
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* to avoid using bit-patterns as valid IDs if they are likely to occur in
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* garbage data, or if they could falsely match on chunks that are really from
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* malloc not palloc. (We can't tell that for most malloc implementations,
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* but it happens that glibc stores flag bits in the same place where we put
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* the MemoryContextMethodID, so the possible values are predictable for it.)
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*/
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typedef enum MemoryContextMethodID
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{
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MCTX_0_RESERVED_UNUSEDMEM_ID, /* 0000 occurs in never-used memory */
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MCTX_1_RESERVED_GLIBC_ID, /* glibc malloc'd chunks usually match 0001 */
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MCTX_2_RESERVED_GLIBC_ID, /* glibc malloc'd chunks > 128kB match 0010 */
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MCTX_ASET_ID,
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MCTX_GENERATION_ID,
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MCTX_SLAB_ID,
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MCTX_ALIGNED_REDIRECT_ID,
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MCTX_BUMP_ID,
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MCTX_8_UNUSED_ID,
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MCTX_9_UNUSED_ID,
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MCTX_10_UNUSED_ID,
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MCTX_11_UNUSED_ID,
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MCTX_12_UNUSED_ID,
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MCTX_13_UNUSED_ID,
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MCTX_14_UNUSED_ID,
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MCTX_15_RESERVED_WIPEDMEM_ID /* 1111 occurs in wipe_mem'd memory */
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} MemoryContextMethodID;
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/*
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* The number of bits that 8-byte memory chunk headers can use to encode the
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* MemoryContextMethodID.
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*/
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#define MEMORY_CONTEXT_METHODID_BITS 4
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#define MEMORY_CONTEXT_METHODID_MASK \
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((((uint64) 1) << MEMORY_CONTEXT_METHODID_BITS) - 1)
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/*
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* This routine handles the context-type-independent part of memory
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* context creation. It's intended to be called from context-type-
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* specific creation routines, and noplace else.
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*/
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extern void MemoryContextCreate(MemoryContext node,
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NodeTag tag,
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MemoryContextMethodID method_id,
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MemoryContext parent,
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const char *name);
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extern void *MemoryContextAllocationFailure(MemoryContext context, Size size,
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int flags);
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pg_noreturn extern void MemoryContextSizeFailure(MemoryContext context, Size size,
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int flags);
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static inline void
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MemoryContextCheckSize(MemoryContext context, Size size, int flags)
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{
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if (unlikely(!AllocSizeIsValid(size)))
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{
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if (!(flags & MCXT_ALLOC_HUGE) || !AllocHugeSizeIsValid(size))
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MemoryContextSizeFailure(context, size, flags);
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}
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}
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#endif /* MEMUTILS_INTERNAL_H */
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