From 1b85f4ec45a5d63188ee3866bd55eb29fdec7fbf Mon Sep 17 00:00:00 2001 From: "Miss Islington (bot)" <31488909+miss-islington@users.noreply.github.com> Date: Sat, 25 May 2019 10:18:34 -0700 Subject: [PATCH] bpo-27987: pymalloc: align by 16bytes on 64bit platform (GH-12850) (cherry picked from commit f0be4bbb9b3cee876249c23f2ae6f38f43fa7495) Co-authored-by: Inada Naoki --- .../2019-04-16-11-52-21.bpo-27987.n2_DcQ.rst | 3 +++ Objects/obmalloc.c | 6 ++++++ 2 files changed, 9 insertions(+) create mode 100644 Misc/NEWS.d/next/Core and Builtins/2019-04-16-11-52-21.bpo-27987.n2_DcQ.rst 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 00000000000..b0f32a5c6c3 --- /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 46e84270b26..885ad537ad9 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)