From afd981d0088772b1d248b66fc171cc3c78161a34 Mon Sep 17 00:00:00 2001 From: Jim Huang Date: Sun, 7 Jul 2019 12:56:40 +0800 Subject: [PATCH 1/5] Use checked unsigned multiplication extension of GCC/Clang Most processors have carry flags which they set on addition overflow, so it is a good idea to access them whenever possible. Most of them also have widening multiply instructions that can be used to detect overflow of the non-widening version. Both GCC and Clang offer a way to detect an overflow for security critical applications. Reference: https://clang.llvm.org/docs/LanguageExtensions.html#checked-arithmetic-builtins --- include/mimalloc-internal.h | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/include/mimalloc-internal.h b/include/mimalloc-internal.h index 3a3f5c4d..a1d1d835 100644 --- a/include/mimalloc-internal.h +++ b/include/mimalloc-internal.h @@ -109,6 +109,9 @@ bool _mi_page_is_valid(mi_page_t* page); #define mi_likely(x) (x) #endif +#ifndef __has_builtin +#define __has_builtin(x) 0 +#endif #if defined(_MSC_VER) #define mi_decl_noinline __declspec(noinline) @@ -141,9 +144,17 @@ bool _mi_page_is_valid(mi_page_t* page); // Overflow detecting multiply #define MI_MUL_NO_OVERFLOW ((size_t)1 << (4*sizeof(size_t))) // sqrt(SIZE_MAX) static inline bool mi_mul_overflow(size_t size, size_t count, size_t* total) { +#if __has_builtin(__builtin_umul_overflow) || __GNUC__ >= 5 +#if (MI_INTPTR_SIZE == 4) + return __builtin_umul_overflow(size, count, total); +#else + return __builtin_umull_overflow(size, count, total); +#endif +#else /* __builtin_umul_overflow is unavailable */ *total = size * count; return ((size >= MI_MUL_NO_OVERFLOW || count >= MI_MUL_NO_OVERFLOW) && size > 0 && (SIZE_MAX / size) < count); +#endif } // Align a byte size to a size in _machine words_, From a215049b4a7382665084410b7be775e1580a5370 Mon Sep 17 00:00:00 2001 From: caixiangyue Date: Fri, 19 Jul 2019 16:23:14 +0800 Subject: [PATCH 2/5] fix typo --- src/os.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/os.c b/src/os.c index f9705992..68a23143 100644 --- a/src/os.c +++ b/src/os.c @@ -195,7 +195,7 @@ static void* mi_win_virtual_alloc(void* addr, size_t size, size_t try_alignment, void* p = NULL; if (use_large_os_page(size, try_alignment)) { if (large_page_try_ok > 0) { - // if a large page page allocation fails, it seems the calls to VirtualAlloc get very expensive. + // if a large page allocation fails, it seems the calls to VirtualAlloc get very expensive. // therefore, once a large page allocation failed, we don't try again for `large_page_try_ok` times. large_page_try_ok--; } From 1ffa48cc61f5cd382566b68a2c9ff572e2a741a5 Mon Sep 17 00:00:00 2001 From: Jim Huang Date: Sun, 21 Jul 2019 21:42:00 +0800 Subject: [PATCH 3/5] Add branch prediction hint for mi_option_get mi_option_get is called frequently in stress tests, and the patch adds extra hint to the compiler to emit instructions that will cause branch prediction to favour the "likely" side of a jump instruction. --- src/options.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/options.c b/src/options.c index 0f588740..84b9d2bf 100644 --- a/src/options.c +++ b/src/options.c @@ -51,7 +51,7 @@ static void mi_option_init(mi_option_desc_t* desc); long mi_option_get(mi_option_t option) { mi_assert(option >= 0 && option < _mi_option_last); mi_option_desc_t* desc = &options[option]; - if (desc->init == UNINIT) { + if (mi_unlikely(desc->init == UNINIT)) { mi_option_init(desc); if (option != mi_option_verbose) { _mi_verbose_message("option '%s': %ld\n", desc->name, desc->value); From c382c72cf23eb0d4bbcf4b0b32bba7158898ebb9 Mon Sep 17 00:00:00 2001 From: Jim Huang Date: Sun, 21 Jul 2019 22:20:05 +0800 Subject: [PATCH 4/5] Avoid using strlen function in loop --- src/options.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/src/options.c b/src/options.c index 0f588740..358d143e 100644 --- a/src/options.c +++ b/src/options.c @@ -176,7 +176,8 @@ static void mi_option_init(mi_option_desc_t* desc) { #pragma warning(suppress:4996) char* s = getenv(buf); if (s == NULL) { - for (size_t i = 0; i < strlen(buf); i++) { + size_t buf_size = strlen(buf); + for (size_t i = 0; i < buf_size; i++) { buf[i] = toupper(buf[i]); } #pragma warning(suppress:4996) @@ -184,7 +185,8 @@ static void mi_option_init(mi_option_desc_t* desc) { } if (s != NULL) { mi_strlcpy(buf, s, sizeof(buf)); - for (size_t i = 0; i < strlen(buf); i++) { + size_t buf_size = strlen(buf); // TODO: use strnlen? + for (size_t i = 0; i < buf_size; i++) { buf[i] = toupper(buf[i]); } if (buf[0]==0 || strstr("1;TRUE;YES;ON", buf) != NULL) { From 146a753d1efac8ac552e02190aaf9f9346765492 Mon Sep 17 00:00:00 2001 From: Jim Huang Date: Mon, 22 Jul 2019 04:45:40 +0800 Subject: [PATCH 5/5] Fix path name in documentation about macOS --- doc/mimalloc-doc.h | 2 +- docs/overrides.html | 2 +- readme.md | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-) diff --git a/doc/mimalloc-doc.h b/doc/mimalloc-doc.h index 16327d2c..57b7dd4c 100644 --- a/doc/mimalloc-doc.h +++ b/doc/mimalloc-doc.h @@ -808,7 +808,7 @@ library so all calls to the standard `malloc` interface are resolved to the _mimalloc_ library. - `env LD_PRELOAD=/usr/lib/libmimalloc.so myprogram` (on Linux, BSD, etc.) -- `env DYLD_INSERT_LIBRARIES=usr/lib/libmimalloc.dylib myprogram` (On macOS) +- `env DYLD_INSERT_LIBRARIES=/usr/lib/libmimalloc.dylib myprogram` (On macOS) Note certain security restrictions may apply when doing this from the [shell](https://stackoverflow.com/questions/43941322/dyld-insert-libraries-ignored-when-calling-application-through-bash). diff --git a/docs/overrides.html b/docs/overrides.html index 16400375..2360a936 100644 --- a/docs/overrides.html +++ b/docs/overrides.html @@ -109,7 +109,7 @@ $(document).ready(function(){initNavTree('overrides.html','');});

On these systems we preload the mimalloc shared library so all calls to the standard malloc interface are resolved to the mimalloc library.

  • env LD_PRELOAD=/usr/lib/libmimalloc.so myprogram (on Linux, BSD, etc.)
    • -

  • env DYLD_INSERT_LIBRARIES=usr/lib/libmimalloc.dylib myprogram (On macOS)

    +

  • env DYLD_INSERT_LIBRARIES=/usr/lib/libmimalloc.dylib myprogram (On macOS)

    Note certain security restrictions may apply when doing this from the shell.

diff --git a/readme.md b/readme.md index 85234c24..8ff19deb 100644 --- a/readme.md +++ b/readme.md @@ -191,7 +191,7 @@ library so all calls to the standard `malloc` interface are resolved to the _mimalloc_ library. - `env LD_PRELOAD=/usr/lib/libmimalloc.so myprogram` (on Linux, BSD, etc.) -- `env DYLD_INSERT_LIBRARIES=usr/lib/libmimalloc.dylib myprogram` (On macOS) +- `env DYLD_INSERT_LIBRARIES=/usr/lib/libmimalloc.dylib myprogram` (On macOS) Note certain security restrictions may apply when doing this from the [shell](https://stackoverflow.com/questions/43941322/dyld-insert-libraries-ignored-when-calling-application-through-bash).