AVX extensions required for bindings on win32-x64

[algol-fi]

Installing node-sass via npm install on Windows Server 2012:

npm install node-sass

downloads a native bindings library for win32-x64. This library, when node-sass is run on a box that does not have AVX enabled, exits with a STATUS_ILLEGAL_INSTRUCTION (0xC000001D). Is it possible to have a different version (compiled without AVX instructions) of the bindings installed if the platform does not support them?

System information:

npm -v
3.10.10
node -v
v6.9.3
node -p process.versions
{ http_parser: '2.7.0',
node: '6.9.3',
v8: '5.1.281.89',
uv: '1.9.1',
zlib: '1.2.8',
ares: '1.10.1-DEV',
icu: '57.1',
modules: '48',
openssl: '1.0.2j' }
node -p process.platform
win32
node -p process.arch
x64
node -p "require('node-sass').info"
node-sass 4.2.0 (Wrapper) [JavaScript]
libsass 3.4.3 (Sass Compiler) [C/C++]
npm ls node-sass
`-- node-sass@4.2.0

[xzyfer]

@am11 are you able to translate this for the non-windows folk?

[am11]

@algol-fi, some questions:

• how did you determine that it's faulting at the AVX instructions?
  • one way to be sure is to recompile with /mapinfo:exports linker flag, enable coredumps and execute the app. When crash happens, lookup the address in map file to get the name of function where crash happened. http://www.codeproject.com/KB/debug/mapfile.aspx.
  • another way is to run node in cmd, attach the VS debugger to this running node.exe process, once attached, run require('node-sass').info in the REPL and see where in our code it throws.
• do you get this failure with other / older versions of node-sass: npm install node-sass@3.3.0 for example?

[algol-fi]

I determined where the fault is happening by running

node.exe node-sass mystyle.sass

under windbg. The content of mystyle.sass is probably not very relevant, but I can try to reproduce the effect with a minimal example.

The stack trace is the following:

 # Child-SP          RetAddr           Call Site
00 00000069`6423db50 00007ff9`2ca12fc4 binding!pow+0xba1 [f:\dd\vctools\crt\fpw32\tran\amd64\pow.asm @ 1616]
01 00000069`6423dc20 00007ff9`2cae86e7 binding!Sass::round+0x54 [s:\node_modules\node-sass\src\libsass\src\util.cpp @ 18]
02 00000069`6423dc70 00007ff9`2ca662be binding!Sass::Inspect::operator()+0x227 [s:\node_modules\node-sass\src\libsass\src\inspect.cpp @ 606]
03 00000069`6423dfc0 00007ff9`2ca2b27c binding!Sass::AST_Node::to_string+0xfe [s:\node_modules\node-sass\src\libsass\src\ast.cpp @ 2301]
04 00000069`6423e2d0 00007ff9`2ca2afdb binding!Sass::Eval::interpolation+0x8ec [s:\node_modules\node-sass\src\libsass\src\eval.cpp @ 1139]
05 00000069`6423e530 00007ff9`2ca2b923 binding!Sass::Eval::interpolation+0x64b [s:\node_modules\node-sass\src\libsass\src\eval.cpp @ 1112]
06 00000069`6423e790 00007ff9`2ca23b49 binding!Sass::Eval::operator()+0x483 [s:\node_modules\node-sass\src\libsass\src\eval.cpp @ 1168]
07 00000069`6423e910 00007ff9`2caae100 binding!Sass::Eval::operator()+0xf9 [s:\node_modules\node-sass\src\libsass\src\eval.cpp @ 447]
08 00000069`6423ead0 00007ff9`2cab3e3a binding!Sass::Expand::operator()+0x6f0 [s:\node_modules\node-sass\src\libsass\src\expand.cpp @ 321]
09 00000069`6423ebb0 00007ff9`2caae84b binding!Sass::Expand::append_block+0x11a [s:\node_modules\node-sass\src\libsass\src\expand.cpp @ 783]
0a 00000069`6423ec10 00007ff9`2cab3e3a binding!Sass::Expand::operator()+0x2eb [s:\node_modules\node-sass\src\libsass\src\expand.cpp @ 357]
0b 00000069`6423ed80 00007ff9`2caae84b binding!Sass::Expand::append_block+0x11a [s:\node_modules\node-sass\src\libsass\src\expand.cpp @ 783]
0c 00000069`6423ede0 00007ff9`2cab3e3a binding!Sass::Expand::operator()+0x2eb [s:\node_modules\node-sass\src\libsass\src\expand.cpp @ 357]
0d 00000069`6423ef50 00007ff9`2caae84b binding!Sass::Expand::append_block+0x11a [s:\node_modules\node-sass\src\libsass\src\expand.cpp @ 783]
0e 00000069`6423efb0 00007ff9`2cab3e3a binding!Sass::Expand::operator()+0x2eb [s:\node_modules\node-sass\src\libsass\src\expand.cpp @ 357]
0f 00000069`6423f120 00007ff9`2caae84b binding!Sass::Expand::append_block+0x11a [s:\node_modules\node-sass\src\libsass\src\expand.cpp @ 783]
10 00000069`6423f180 00007ff9`2cab3e3a binding!Sass::Expand::operator()+0x2eb [s:\node_modules\node-sass\src\libsass\src\expand.cpp @ 357]
11 00000069`6423f2f0 00007ff9`2caabaa6 binding!Sass::Expand::append_block+0x11a [s:\node_modules\node-sass\src\libsass\src\expand.cpp @ 783]
12 00000069`6423f350 00007ff9`2ca09e19 binding!Sass::Expand::operator()+0x216 [s:\node_modules\node-sass\src\libsass\src\expand.cpp @ 87]
13 00000069`6423f430 00007ff9`2ca0938b binding!Sass::Context::compile+0x349 [s:\node_modules\node-sass\src\libsass\src\context.cpp @ 655]
14 00000069`6423f760 00007ff9`2c9f94f6 binding!Sass::File_Context::parse+0x55b [s:\node_modules\node-sass\src\libsass\src\context.cpp @ 584]
15 00000069`6423f980 00007ff9`2c9f9cf1 binding!Sass::sass_parse_block+0x156 [s:\node_modules\node-sass\src\libsass\src\sass_context.cpp @ 228]
16 00000069`6423fa70 00007ff9`2c9f98c0 binding!sass_compiler_parse+0x61 [s:\node_modules\node-sass\src\libsass\src\sass_context.cpp @ 471]
17 00000069`6423faa0 00007ff9`2c9f9c72 binding!sass_compile_context+0x30 [s:\node_modules\node-sass\src\libsass\src\sass_context.cpp @ 360]
18 00000069`6423fae0 00007ff6`c5831c57 binding!sass_compile_file_context+0xd2 [s:\node_modules\node-sass\src\libsass\src\sass_context.cpp @ 458]
19 00000069`6423fb40 00007ff6`c581de14 node!uv_fs_poll_getpath+0x627
1a 00000069`6423fb80 00007ff6`c5f92211 node!uv_once+0x114
1b 00000069`6423fbd0 00007ff9`4ab713d2 node!uncompress+0x1db41
1c 00000069`6423fc00 00007ff9`4bf754e4 KERNEL32!BaseThreadInitThunk+0x22
1d 00000069`6423fc30 00000000`00000000 ntdll!RtlUserThreadStart+0x34

The referenced pow.asm is using AVX, since the current executing instruction is

00007ff9`2cb3d691 c5fb11442410    vmovsd  qword ptr [rsp+10h],xmm0 ss:00000069`6423db60=0000000000000008

and c5 is the 2-byte VEX prefix used for AVX instructions.

[am11]

Thanks for the details and stack trace @algol-fi, it does look like the case. The exception site (std:pow call) is: https://github.com/sass/libsass/blob/b28de0/src/util.cpp#L18.

Can you please try rebuilding the source locally, to see if this issue is still reproducible (i.e. confirming our compiler/linker flags are all set correctly and that we only need a build machine for non-SSE128 binaries). Instructions to build are available here: https://github.com/sass/node-sass#rebuilding-binaries (you will need VC build tools or VS2013+).

[algol-fi]

I rebuilt the source locally, replaced the binding.node in the package with the built one and everything seems to be working fine. No illegal instruction and a correct CSS file in output.

[am11]

Thanks for the confirmation @algol-fi!

@xzyfer, this was a bug in VS2013, that was fixed in VS2015 https://connect.microsoft.com/VisualStudio/Feedback/Details/981479 (see last comment from Microsoft team)

Solution:

// in LibSass -> util.cpp, after #include<cmath> statement:
#if defined(_MSC_VER) && _MSC_VER >= 1800 && _MSC_VER < 1900 && defined(_M_X64) || defined(__x86_64__)
  // FIXME: Remove this workaround when we switch to VS2015+.
  _set_FMA3_enable(0);
#endif

FTR, the AVX instructions were also causing issues in node.js (when it is turned off in Boot Configuration Data by the user/admin: bcdedit tweaking), and was fixed after they moved to VS2015 nodejs/node#7261 (without _set_FMA3_enable hack). Perhaps, we should reconsider our stance about VS2013 and move forward? Even Chromimum guys are building with VS2015 Update 3 [ref] (since September 8, 2016). :)

[saper]

@am11 thank you for your analysis. I believe the stacktrace is correct and identifies the problem. We should switch to VS2015 for all nodes starting from I believe v6.2.0 - this is when node itself switched to VS2015.

The next workaround I would try is to use msvcr120.dll from vs2015, if that works at all.

[xzyfer]

Nice work @am11. I've just read through those links and I agree with @saper that we should try to build v6+ with VS2015.

[mgreter]

@am11 can you create a PR for libsass to include the hotfix? I guess it doesn't hurt to include it if it fixes a possible bug. I guess there are no real side effects from this change? Thanks!