[compiler-rt] r300889 - [asan] Optimize strchr for strict_string_checks=false
Vitaly Buka via llvm-commits
llvm-commits at lists.llvm.org
Fri Apr 21 11:11:01 PDT 2017
Thank you!
On Fri, Apr 21, 2017 at 1:36 AM Diana Picus <diana.picus at linaro.org> wrote:
> Reverted in r300955 since the bots have been red for over 7h. Sorry!
> Please let me know if I can help reproduce.
>
> Cheers,
> Diana
>
> On 21 April 2017 at 10:20, Diana Picus <diana.picus at linaro.org> wrote:
> > I don't think r300939 fixed everything:
> > http://lab.llvm.org:8011/builders/clang-cmake-armv7-a15-full/builds/6087
> >
> >
> > On 21 April 2017 at 03:30, Vitaly Buka via llvm-commits
> > <llvm-commits at lists.llvm.org> wrote:
> >> Thanks,
> >> Maybe r300939 would fix.
> >>
> >> On Thu, Apr 20, 2017 at 6:20 PM Ahmed Bougacha <
> ahmed.bougacha at gmail.com>
> >> wrote:
> >>>
> >>> Hey Vitaly,
> >>>
> >>> I saw your fixes in r300906 and r300935, but this fails differently
> >>> for me on Darwin:
> >>>
> >>>
> >>> ASAN:DEADLYSIGNAL
> >>> =================================================================
> >>> ==52312==ERROR: AddressSanitizer: BUS on unknown address
> >>> 0x00010affd000 (pc 0x7fff999a7168 bp 0x7fff57e31270 sp 0x7fff57e31270
> >>> T0)
> >>> #0 0x7fff999a7167 in strlen (libsystem_c.dylib:x86_64+0x1167)
> >>> #1 0x107dee5bb in wrap_strchr sanitizer_common_interceptors.inc:578
> >>> #2 0x107dceaa5 in main strchr.c:29
> >>> #3 0x7fff970345ac in start (libdyld.dylib:x86_64+0x35ac)
> >>>
> >>> ==52312==Register values:
> >>> ....
> >>> AddressSanitizer can not provide additional info.
> >>> SUMMARY: AddressSanitizer: BUS (libsystem_c.dylib:x86_64+0x1167) in
> strlen
> >>> ==52312==ABORTING
> >>>
> >>>
> >>> Does that ring a bell?
> >>>
> >>> Thanks!
> >>> -Ahmed
> >>>
> >>>
> >>> On Thu, Apr 20, 2017 at 1:59 PM, Vitaly Buka via llvm-commits
> >>> <llvm-commits at lists.llvm.org> wrote:
> >>> > Author: vitalybuka
> >>> > Date: Thu Apr 20 15:59:37 2017
> >>> > New Revision: 300889
> >>> >
> >>> > URL: http://llvm.org/viewvc/llvm-project?rev=300889&view=rev
> >>> > Log:
> >>> > [asan] Optimize strchr for strict_string_checks=false
> >>> >
> >>> > Summary:
> >>> > strchr interceptor does not need to call strlen if
> strict_string_checks
> >>> > is not
> >>> > enabled. Unnecessary strlen calls affect python parser performance.
> >>> >
> >>> > Reviewers: eugenis, kcc
> >>> >
> >>> > Subscribers: llvm-commits, kubamracek
> >>> >
> >>> > Differential Revision: https://reviews.llvm.org/D32264
> >>> >
> >>> > Added:
> >>> > compiler-rt/trunk/test/asan/TestCases/Posix/strchr.c
> >>> > Modified:
> >>> >
> >>> >
> compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_interceptors.inc
> >>> >
> >>> > Modified:
> >>> >
> compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_interceptors.inc
> >>> > URL:
> >>> >
> http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_interceptors.inc?rev=300889&r1=300888&r2=300889&view=diff
> >>> >
> >>> >
> ==============================================================================
> >>> > ---
> >>> >
> compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_interceptors.inc
> >>> > (original)
> >>> > +++
> >>> >
> compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_interceptors.inc Thu
> >>> > Apr 20 15:59:37 2017
> >>> > @@ -139,12 +139,9 @@ bool PlatformHasDifferentMemcpyAndMemmov
> >>> > #define COMMON_INTERCEPTOR_NOTHING_IS_INITIALIZED (0)
> >>> > #endif
> >>> >
> >>> > -#define COMMON_INTERCEPTOR_READ_STRING_OF_LEN(ctx, s, len, n)
> \
> >>> > - COMMON_INTERCEPTOR_READ_RANGE((ctx), (s),
> \
> >>> > - common_flags()->strict_string_checks ? (len) + 1 : (n) )
> >>> > -
> >>> > #define COMMON_INTERCEPTOR_READ_STRING(ctx, s, n)
> \
> >>> > - COMMON_INTERCEPTOR_READ_STRING_OF_LEN((ctx), (s),
> REAL(strlen)(s),
> >>> > (n))
> >>> > + COMMON_INTERCEPTOR_READ_RANGE((ctx), (s),
> \
> >>> > + common_flags()->strict_string_checks ? (REAL(strlen)(s)) + 1 :
> >>> > (n) )
> >>> >
> >>> > #ifndef COMMON_INTERCEPTOR_ON_DLOPEN
> >>> > #define COMMON_INTERCEPTOR_ON_DLOPEN(filename, flag) \
> >>> > @@ -450,8 +447,7 @@ static inline void StrstrCheck(void *ctx
> >>> > const char *s2) {
> >>> > uptr len1 = REAL(strlen)(s1);
> >>> > uptr len2 = REAL(strlen)(s2);
> >>> > - COMMON_INTERCEPTOR_READ_STRING_OF_LEN(ctx, s1, len1,
> >>> > - r ? r - s1 + len2 : len1 +
> >>> > 1);
> >>> > + COMMON_INTERCEPTOR_READ_STRING(ctx, s1, r ? r - s1 + len2 :
> len1 +
> >>> > 1);
> >>> > COMMON_INTERCEPTOR_READ_RANGE(ctx, s2, len2 + 1);
> >>> > }
> >>> > #endif
> >>> > @@ -577,10 +573,11 @@ INTERCEPTOR(char*, strchr, const char *s
> >>> > return internal_strchr(s, c);
> >>> > COMMON_INTERCEPTOR_ENTER(ctx, strchr, s, c);
> >>> > char *result = REAL(strchr)(s, c);
> >>> > - uptr len = internal_strlen(s);
> >>> > - uptr n = result ? result - s + 1 : len + 1;
> >>> > - if (common_flags()->intercept_strchr)
> >>> > - COMMON_INTERCEPTOR_READ_STRING_OF_LEN(ctx, s, len, n);
> >>> > + if (common_flags()->intercept_strchr) {
> >>> > + // Keep strlen as macro argument, as macro may ignore it.
> >>> > + COMMON_INTERCEPTOR_READ_STRING(ctx, s,
> >>> > + (result ? result - s : REAL(strlen)(s)) + 1);
> >>> > + }
> >>> > return result;
> >>> > }
> >>> > #define INIT_STRCHR COMMON_INTERCEPT_FUNCTION(strchr)
> >>> > @@ -609,9 +606,8 @@ INTERCEPTOR(char*, strrchr, const char *
> >>> > if (COMMON_INTERCEPTOR_NOTHING_IS_INITIALIZED)
> >>> > return internal_strrchr(s, c);
> >>> > COMMON_INTERCEPTOR_ENTER(ctx, strrchr, s, c);
> >>> > - uptr len = internal_strlen(s);
> >>> > if (common_flags()->intercept_strchr)
> >>> > - COMMON_INTERCEPTOR_READ_STRING_OF_LEN(ctx, s, len, len + 1);
> >>> > + COMMON_INTERCEPTOR_READ_RANGE(ctx, s, REAL(strlen)(s) + 1);
> >>> > return REAL(strrchr)(s, c);
> >>> > }
> >>> > #define INIT_STRRCHR COMMON_INTERCEPT_FUNCTION(strrchr)
> >>> >
> >>> > Added: compiler-rt/trunk/test/asan/TestCases/Posix/strchr.c
> >>> > URL:
> >>> >
> http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/test/asan/TestCases/Posix/strchr.c?rev=300889&view=auto
> >>> >
> >>> >
> ==============================================================================
> >>> > --- compiler-rt/trunk/test/asan/TestCases/Posix/strchr.c (added)
> >>> > +++ compiler-rt/trunk/test/asan/TestCases/Posix/strchr.c Thu Apr 20
> >>> > 15:59:37 2017
> >>> > @@ -0,0 +1,36 @@
> >>> > +// Test strchr for strict_string_checks=false does not look beyond
> >>> > necessary
> >>> > +// char.
> >>> > +// RUN: %clang_asan %s -o %t
> >>> > +// RUN: %env_asan_opts=strict_string_checks=false %run %t 2>&1
> >>> > +// RUN: %env_asan_opts=strict_string_checks=true not %run %t 2>&1 |
> >>> > FileCheck %s
> >>> > +
> >>> > +#include <assert.h>
> >>> > +#include <stdint.h>
> >>> > +#include <stdlib.h>
> >>> > +#include <string.h>
> >>> > +#include <sys/mman.h>
> >>> > +#include <unistd.h>
> >>> > +
> >>> > +int main(int argc, char **argv) {
> >>> > + size_t page_size = sysconf(_SC_PAGE_SIZE);
> >>> > + size_t size = 2 * page_size;
> >>> > + char *s = (char *)mmap(0, size, PROT_READ | PROT_WRITE,
> >>> > + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
> >>> > + assert(s);
> >>> > + assert(((uintptr_t)s & (page_size - 1)) == 0);
> >>> > + memset(s, 'o', size);
> >>> > + s[size - 1] = 0;
> >>> > +
> >>> > + char *p = s + page_size - 1;
> >>> > + *p = 'x';
> >>> > +
> >>> > + if (mprotect(p + 1, 1, PROT_NONE))
> >>> > + return 1;
> >>> > + char *r = strchr(s, 'x');
> >>> > + // CHECK: AddressSanitizer: SEGV on unknown address
> >>> > + // CHECK: The signal is caused by a READ memory access
> >>> > + // CHECK: strchr.c:[[@LINE-3]]
> >>> > + assert(r == p);
> >>> > +
> >>> > + return 0;
> >>> > +}
> >>> >
> >>> >
> >>> > _______________________________________________
> >>> > llvm-commits mailing list
> >>> > llvm-commits at lists.llvm.org
> >>> > http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
> >>
> >>
> >> _______________________________________________
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> >>
>
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