[llvm] r234343 - Enable W4 warnings by default for MSVC builds

[Aaron Ballman]

When I do that, the first line of output shows /W3:


E:\llvm\x64>"D:\Program Files (x86)\Microsoft Visual Studio
12.0\VC\vcvarsall.bat" amd64

E:\llvm\x64>cmake -G "Visual Studio 12" ..\llvm
CMAKE_CXX_FLAGS =  /DWIN32 /D_WINDOWS /W3 /GR /EHsc
....

~Aaron

On Mon, Apr 13, 2015 at 2:37 PM, Zachary Turner <zturner at google.com> wrote:
> Also what version of CMake are you using?  Maybe it's an issue with CMake >=
> 3.0?  Try putting the following line at the top of your CMakeLists.txt
>
> message("CMAKE_CXX_FLAGS = ${CMAKE_CXX_FLAGS}")
>
> If you don't see /W3 in there, you won't hit the problem.
>
> On Mon, Apr 13, 2015 at 11:36 AM Zachary Turner <zturner at google.com> wrote:
>>
>> Just realized maybe 2012 was a typo.  Are you actually still using 2012?
>> I thought support was dropped.
>>
>> On Mon, Apr 13, 2015 at 11:33 AM Aaron Ballman <aaron at aaronballman.com>
>> wrote:
>>>
>>> I do not get the warnings when building x64 or x86 on Windows 7, MSVC
>>> 2012, debug build. This is when building LLVM, Clang, lld, and clang
>>> tools extra
>>>
>>> ~Aaron
>>>
>>> On Mon, Apr 13, 2015 at 2:22 PM, Zachary Turner <zturner at google.com>
>>> wrote:
>>> > I'm building x64.  Can you try that?  Run "vcvarsall amd64" before
>>> > building
>>> > LLVM
>>> >
>>> > On Mon, Apr 13, 2015 at 11:21 AM Kaylor, Andrew
>>> > <andrew.kaylor at intel.com>
>>> > wrote:
>>> >>
>>> >> I haven’t seen that.  I’m not seeing any warnings right now.
>>> >>
>>> >>
>>> >>
>>> >> From: Zachary Turner [mailto:zturner at google.com]
>>> >> Sent: Monday, April 13, 2015 11:17 AM
>>> >> To: Kaylor, Andrew; llvm-commits at cs.uiuc.edu
>>> >> Subject: Re: [llvm] r234343 - Enable W4 warnings by default for MSVC
>>> >> builds
>>> >>
>>> >>
>>> >>
>>> >> Hi Andy, this is causing a huge slew of warning spam.  Is this
>>> >> expected?
>>> >> CMake passes /W3 by default, so  every single translation unit I
>>> >> compile
>>> >> gives me the following warning:
>>> >>
>>> >>
>>> >>
>>> >> cl : Command line warning D9025 : overriding '/W3' with '/W4'
>>> >>
>>> >>
>>> >>
>>> >> Furthermore, since this is a command line warning and not a compiler
>>> >> warning, it cannot be suppressed.  Unless you have any better ideas on
>>> >> how
>>> >> to address this, I think this should be reverted.
>>> >>
>>> >>
>>> >>
>>> >> On Tue, Apr 7, 2015 at 12:07 PM Andrew Kaylor
>>> >> <andrew.kaylor at intel.com>
>>> >> wrote:
>>> >>
>>> >> Author: akaylor
>>> >> Date: Tue Apr  7 14:01:01 2015
>>> >> New Revision: 234343
>>> >>
>>> >> URL: http://llvm.org/viewvc/llvm-project?rev=234343&view=rev
>>> >> Log:
>>> >> Enable W4 warnings by default for MSVC builds
>>> >>
>>> >> Modified:
>>> >>     llvm/trunk/CMakeLists.txt
>>> >>
>>> >> Modified: llvm/trunk/CMakeLists.txt
>>> >> URL:
>>> >>
>>> >> http://llvm.org/viewvc/llvm-project/llvm/trunk/CMakeLists.txt?rev=234343&r1=234342&r2=234343&view=diff
>>> >>
>>> >>
>>> >> ==============================================================================
>>> >> --- llvm/trunk/CMakeLists.txt (original)
>>> >> +++ llvm/trunk/CMakeLists.txt Tue Apr  7 14:01:01 2015
>>> >> @@ -233,14 +233,7 @@ list(REMOVE_DUPLICATES LLVM_TARGETS_TO_B
>>> >>  include(AddLLVMDefinitions)
>>> >>
>>> >>  option(LLVM_ENABLE_PIC "Build Position-Independent Code" ON)
>>> >> -
>>> >> -# MSVC has a gazillion warnings with this.
>>> >> -if( MSVC )
>>> >> -  option(LLVM_ENABLE_WARNINGS "Enable compiler warnings." OFF)
>>> >> -else()
>>> >> -  option(LLVM_ENABLE_WARNINGS "Enable compiler warnings." ON)
>>> >> -endif()
>>> >> -
>>> >> +option(LLVM_ENABLE_WARNINGS "Enable compiler warnings." ON)
>>> >>  option(LLVM_ENABLE_MODULES "Compile with C++ modules enabled." OFF)
>>> >>  option(LLVM_ENABLE_CXX1Y "Compile with C++1y enabled." OFF)
>>> >>  option(LLVM_ENABLE_LIBCXX "Use libc++ if available." OFF)
>>> >>
>>> >>
>>> >> _______________________________________________
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>>> >> llvm-commits at cs.uiuc.edu
>>> >> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
>>> >
>>> >
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>>> >