From: Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com> Date: Sat, 25 May 2019 17:18:34 +0000 (-0700) Subject: bpo-27987: pymalloc: align by 16bytes on 64bit platform (GH-12850) X-Git-Tag: v3.7.4rc1~103 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=1b85f4ec45a5d63188ee3866bd55eb29fdec7fbf;p=thirdparty%2FPython%2Fcpython.git bpo-27987: pymalloc: align by 16bytes on 64bit platform (GH-12850) (cherry picked from commit f0be4bbb9b3cee876249c23f2ae6f38f43fa7495) Co-authored-by: Inada Naoki --- diff --git a/Misc/NEWS.d/next/Core and Builtins/2019-04-16-11-52-21.bpo-27987.n2_DcQ.rst b/Misc/NEWS.d/next/Core and Builtins/2019-04-16-11-52-21.bpo-27987.n2_DcQ.rst new file mode 100644 index 000000000000..b0f32a5c6c3f --- /dev/null +++ b/Misc/NEWS.d/next/Core and Builtins/2019-04-16-11-52-21.bpo-27987.n2_DcQ.rst @@ -0,0 +1,3 @@ +pymalloc returns memory blocks aligned by 16 bytes, instead of 8 bytes, on +64-bit platforms to conform x86-64 ABI. Recent compilers assume this alignment +more often. Patch by Inada Naoki. diff --git a/Objects/obmalloc.c b/Objects/obmalloc.c index 46e84270b26e..885ad537ad95 100644 --- a/Objects/obmalloc.c +++ b/Objects/obmalloc.c @@ -788,8 +788,14 @@ static int running_on_valgrind = -1; * * You shouldn't change this unless you know what you are doing. */ + +#if SIZEOF_VOID_P > 4 +#define ALIGNMENT 16 /* must be 2^N */ +#define ALIGNMENT_SHIFT 4 +#else #define ALIGNMENT 8 /* must be 2^N */ #define ALIGNMENT_SHIFT 3 +#endif /* Return the number of bytes in size class I, as a uint. */ #define INDEX2SIZE(I) (((uint)(I) + 1) << ALIGNMENT_SHIFT)