r230644 - [msan] Change track-origins default mode from 1 to 2.
Kostya Serebryany
kcc at google.com
Thu Feb 26 10:24:33 PST 2015
woohoo!
On Thu, Feb 26, 2015 at 7:59 AM, Evgeniy Stepanov <eugeni.stepanov at gmail.com
> wrote:
> Author: eugenis
> Date: Thu Feb 26 09:59:30 2015
> New Revision: 230644
>
> URL: http://llvm.org/viewvc/llvm-project?rev=230644&view=rev
> Log:
> [msan] Change track-origins default mode from 1 to 2.
>
> Change -fsanitize-memory-track-origins to be equivalent to
> -fsanitize-memory-track-origins=2.
>
> Track-origins=2 provides a lot more detailed reports at the cost of
> some additional slowdown (ranging from none to, sometimes, 3x; ~3% average
> on
> SPEC2006).
>
> Modified:
> cfe/trunk/docs/MemorySanitizer.rst
> cfe/trunk/docs/UsersManual.rst
> cfe/trunk/lib/Driver/SanitizerArgs.cpp
> cfe/trunk/test/Driver/fsanitize.c
>
> Modified: cfe/trunk/docs/MemorySanitizer.rst
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/docs/MemorySanitizer.rst?rev=230644&r1=230643&r2=230644&view=diff
>
> ==============================================================================
> --- cfe/trunk/docs/MemorySanitizer.rst (original)
> +++ cfe/trunk/docs/MemorySanitizer.rst Thu Feb 26 09:59:30 2015
> @@ -110,32 +110,12 @@ Origin Tracking
>
> MemorySanitizer can track origins of unitialized values, similar to
> Valgrind's --track-origins option. This feature is enabled by
> -``-fsanitize-memory-track-origins`` Clang option. With the code from
> +``-fsanitize-memory-track-origins=2`` (or simply
> +``-fsanitize-memory-track-origins``) Clang option. With the code from
> the example above,
>
> .. code-block:: console
>
> - % clang -fsanitize=memory -fsanitize-memory-track-origins
> -fno-omit-frame-pointer -g -O2 umr.cc
> - % ./a.out
> - WARNING: MemorySanitizer: use-of-uninitialized-value
> - #0 0x7f7893912f0b in main umr2.cc:6
> - #1 0x7f789249b76c in __libc_start_main libc-start.c:226
> -
> - Uninitialized value was created by a heap allocation
> - #0 0x7f7893901cbd in operator new[](unsigned long)
> msan_new_delete.cc:44
> - #1 0x7f7893912e06 in main umr2.cc:4
> -
> -Origin tracking has proved to be very useful for debugging MemorySanitizer
> -reports. It slows down program execution by a factor of 1.5x-2x on top
> -of the usual MemorySanitizer slowdown.
> -
> -MemorySanitizer can provide even more information with
> -``-fsanitize-memory-track-origins=2`` flag. In this mode reports
> -include information about intermediate stores the uninitialized value went
> -through.
> -
> -.. code-block:: console
> -
> % cat umr2.cc
> #include <stdio.h>
>
> @@ -162,6 +142,15 @@ through.
> #0 0x7f7893901cbd in operator new[](unsigned long)
> msan_new_delete.cc:44
> #1 0x7f7893912e06 in main umr2.cc:4
>
> +By default, MemorySanitizer collects both allocation points and all
> +intermediate stores the uninitialized value went through. Origin
> +tracking has proved to be very useful for debugging MemorySanitizer
> +reports. It slows down program execution by a factor of 1.5x-2x on top
> +of the usual MemorySanitizer slowdown.
> +
> +Clang option ``-fsanitize-memory-track-origins=1`` enabled a slightly
> +faster mode when MemorySanitizer collects only allocation points but
> +not intermediate stores.
>
> Handling external code
> ============================
>
> Modified: cfe/trunk/docs/UsersManual.rst
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/docs/UsersManual.rst?rev=230644&r1=230643&r2=230644&view=diff
>
> ==============================================================================
> --- cfe/trunk/docs/UsersManual.rst (original)
> +++ cfe/trunk/docs/UsersManual.rst Thu Feb 26 09:59:30 2015
> @@ -1030,10 +1030,11 @@ are listed below.
> uninitialized bits came from. Slows down execution by additional
> 1.5x-2x.
>
> - Possible values for level are 0 (off), 1 (default), 2. Level 2 adds
> more
> - sections to MemorySanitizer reports describing the order of memory
> stores
> - the uninitialized value went through. Beware, this mode may use a
> lot of
> - extra memory.
> + Possible values for level are 0 (off), 1, 2 (default). Level 2
> + adds more sections to MemorySanitizer reports describing the
> + order of memory stores the uninitialized value went
> + through. This mode may use extra memory in programs that copy
> + uninitialized memory a lot.
>
> Extra features of UndefinedBehaviorSanitizer:
>
>
> Modified: cfe/trunk/lib/Driver/SanitizerArgs.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Driver/SanitizerArgs.cpp?rev=230644&r1=230643&r2=230644&view=diff
>
> ==============================================================================
> --- cfe/trunk/lib/Driver/SanitizerArgs.cpp (original)
> +++ cfe/trunk/lib/Driver/SanitizerArgs.cpp Thu Feb 26 09:59:30 2015
> @@ -360,7 +360,7 @@ SanitizerArgs::SanitizerArgs(const ToolC
> options::OPT_fsanitize_memory_track_origins,
>
> options::OPT_fno_sanitize_memory_track_origins)) {
> if
> (A->getOption().matches(options::OPT_fsanitize_memory_track_origins)) {
> - MsanTrackOrigins = 1;
> + MsanTrackOrigins = 2;
> } else if (A->getOption().matches(
> options::OPT_fno_sanitize_memory_track_origins)) {
> MsanTrackOrigins = 0;
>
> Modified: cfe/trunk/test/Driver/fsanitize.c
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Driver/fsanitize.c?rev=230644&r1=230643&r2=230644&view=diff
>
> ==============================================================================
> --- cfe/trunk/test/Driver/fsanitize.c (original)
> +++ cfe/trunk/test/Driver/fsanitize.c Thu Feb 26 09:59:30 2015
> @@ -66,11 +66,13 @@
> // RUN: %clang -target x86_64-linux-gnu -fsanitize=memory -pie %s -###
> 2>&1
> // OK
>
> -// RUN: %clang -target x86_64-linux-gnu -fsanitize=memory
> -fsanitize-memory-track-origins -pie %s -### 2>&1 | FileCheck %s
> --check-prefix=CHECK-TRACK-ORIGINS-1
> +// RUN: %clang -target x86_64-linux-gnu -fsanitize=memory
> -fsanitize-memory-track-origins -pie %s -### 2>&1 | FileCheck %s
> --check-prefix=CHECK-TRACK-ORIGINS-2
> // RUN: %clang -target x86_64-linux-gnu -fsanitize=memory
> -fsanitize-memory-track-origins=1 -pie %s -### 2>&1 | FileCheck %s
> --check-prefix=CHECK-TRACK-ORIGINS-1
> -// RUN: %clang -target x86_64-linux-gnu -fsanitize=memory
> -fsanitize-memory-track-origins=2 -fsanitize-memory-track-origins -pie %s
> -### 2>&1 | FileCheck %s --check-prefix=CHECK-TRACK-ORIGINS-1
> -// RUN: %clang -target x86_64-linux-gnu -fsanitize=memory
> -fno-sanitize-memory-track-origins -fsanitize-memory-track-origins -pie %s
> -### 2>&1 | FileCheck %s --check-prefix=CHECK-TRACK-ORIGINS-1
> -// RUN: %clang -target x86_64-linux-gnu -fsanitize=memory
> -fsanitize-memory-track-origins=0 -fsanitize-memory-track-origins -pie %s
> -### 2>&1 | FileCheck %s --check-prefix=CHECK-TRACK-ORIGINS-1
> +// RUN: %clang -target x86_64-linux-gnu -fsanitize=memory
> -fsanitize-memory-track-origins=1 -fsanitize-memory-track-origins -pie %s
> -### 2>&1 | FileCheck %s --check-prefix=CHECK-TRACK-ORIGINS-2
> +// RUN: %clang -target x86_64-linux-gnu -fsanitize=memory
> -fsanitize-memory-track-origins=2 -fsanitize-memory-track-origins -pie %s
> -### 2>&1 | FileCheck %s --check-prefix=CHECK-TRACK-ORIGINS-2
> +// RUN: %clang -target x86_64-linux-gnu -fsanitize=memory
> -fno-sanitize-memory-track-origins -fsanitize-memory-track-origins -pie %s
> -### 2>&1 | FileCheck %s --check-prefix=CHECK-TRACK-ORIGINS-2
> +// RUN: %clang -target x86_64-linux-gnu -fsanitize=memory
> -fsanitize-memory-track-origins=0 -fsanitize-memory-track-origins=1 -pie %s
> -### 2>&1 | FileCheck %s --check-prefix=CHECK-TRACK-ORIGINS-1
> +// RUN: %clang -target x86_64-linux-gnu -fsanitize=memory
> -fsanitize-memory-track-origins=0 -fsanitize-memory-track-origins -pie %s
> -### 2>&1 | FileCheck %s --check-prefix=CHECK-TRACK-ORIGINS-2
>
> // CHECK-TRACK-ORIGINS-1: -fsanitize-memory-track-origins=1
>
>
>
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