MantisBT - CMake
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IDProjectCategoryView StatusDate SubmittedLast Update
0016038CMakeCMakepublic2016-03-30 14:512016-06-10 14:21
ReporterReid Kleckner 
Assigned ToBrad King 
PrioritynormalSeverityminorReproducibilityalways
StatusclosedResolutionfixed 
PlatformOSWindowsOS Version
Product VersionCMake 3.4.3 
Target VersionCMake 3.6Fixed in VersionCMake 3.6 
Summary0016038: CHECK_COMPILER_FLAG_COMMON_PATTERNS doesn't match clang-cl's unknown argument warning
DescriptionThese are the patterns that cmake appears to be looking for to spot unsupported options:
     FAIL_REGEX "unknown .*option" # Clang
     FAIL_REGEX "optimization flag .* not supported" # Clang

But we actually have two other diagnostics, one of which needs to be matched:
def err_drv_unknown_argument : Error<"unknown argument: '%0'">;
def warn_drv_unknown_argument_clang_cl : Warning<
  "unknown argument ignored in clang-cl: '%0'">,
  InGroup<UnknownArgument>;

The first is an error diagnostic, so you don't need to match it. We added the second because MSVC ignores unknown flags, and clang-cl needs to do the same. We chose the text for consistency with the error diagnostic.
Steps To ReproduceHave this in a cmake project:
check_cxx_compiler_flag(-not-a-real-flag IS_REAL_FLAG)

Configure the project with clang-cl as the compiler.

Observe that IS_REAL_FLAG is ON.
Additional InformationThis came up while I was trying to build asan with clang-cl.
TagsNo tags attached.
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Issue History
Date ModifiedUsernameFieldChange
2016-03-30 14:51Reid KlecknerNew Issue
2016-03-31 08:56Brad KingNote Added: 0040774
2016-03-31 08:56Brad KingAssigned To => Brad King
2016-03-31 08:56Brad KingStatusnew => resolved
2016-03-31 08:56Brad KingResolutionopen => fixed
2016-03-31 08:56Brad KingFixed in Version => CMake 3.6
2016-03-31 08:56Brad KingTarget Version => CMake 3.6
2016-03-31 14:03Reid KlecknerNote Added: 0040784
2016-03-31 14:10Brad KingNote Added: 0040785
2016-03-31 19:35Reid KlecknerNote Added: 0040786
2016-06-10 14:21Kitware RobotNote Added: 0041206
2016-06-10 14:21Kitware RobotStatusresolved => closed

Notes
(0040774)
Brad King   
2016-03-31 08:56   
Thanks. Please try this fix:

 Check*CompilerFlag: Add another pattern for Clang
 https://cmake.org/gitweb?p=cmake.git;a=commitdiff;h=17c4863c [^]
(0040784)
Reid Kleckner   
2016-03-31 14:03   
Do you think a shorter pattern of just "unknown argument" would be better?
(0040785)
Brad King   
2016-03-31 14:10   
Many of the other matching expressions include the "ignored" part, so how about "unknown argument ignored":

 Check*CompilerFlag: Add another pattern for Clang
 https://cmake.org/gitweb?p=cmake.git;a=commitdiff;h=fae80ee2 [^]

?
(0040786)
Reid Kleckner   
2016-03-31 19:35   
Yep, sounds good. BTW, I checked out that commit, and it fixed the asan runtime build issues with clang-cl. Thanks!
(0041206)
Kitware Robot   
2016-06-10 14:21   
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