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[cmake] Refactor warning flag logic to use Unix warnings with clang-cl
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Summary:
clang-cl understands the GCC-style -W[no-]foo flags, and for the most
part ignores MSVC -wd flags. So, let's pass the curated set of warning
flags we use on Unix on Windows. We can also stop passing /W4 -wd*,
which for the most part corresponds to -Wall -Wextra with a bunch of
flags that we mostly ignore.

I had to disable -Wnon-virtual-dtor on Windows, because it fires on
every COM class ever. I filed PR32286 to fix this.

So far I've only found two instances of -Wstring-conversion in the
WinASan code, which I'll fix. Other than that we seem clean.

Reviewers: hans

Subscribers: mgorny, llvm-commits

Differential Revision: https://reviews.llvm.org/D30992

llvm-svn: 297964
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@rnk
rnk committed Mar 16, 2017
1 parent 1275a2d commit 9f3585d
Showing 1 changed file with 146 additions and 137 deletions.
283 changes: 146 additions & 137 deletions llvm/cmake/modules/HandleLLVMOptions.cmake
View file
Original file line number Diff line number Diff line change
Expand Up @@ -311,89 +311,10 @@ if( MSVC )
-D_UNICODE
)

set(msvc_warning_flags
# Disabled warnings.
-wd4141 # Suppress ''modifier' : used more than once' (because of __forceinline combined with inline)
-wd4146 # Suppress 'unary minus operator applied to unsigned type, result still unsigned'
-wd4180 # Suppress 'qualifier applied to function type has no meaning; ignored'
-wd4244 # Suppress ''argument' : conversion from 'type1' to 'type2', possible loss of data'
-wd4258 # Suppress ''var' : definition from the for loop is ignored; the definition from the enclosing scope is used'
-wd4267 # Suppress ''var' : conversion from 'size_t' to 'type', possible loss of data'
-wd4291 # Suppress ''declaration' : no matching operator delete found; memory will not be freed if initialization throws an exception'
-wd4345 # Suppress 'behavior change: an object of POD type constructed with an initializer of the form () will be default-initialized'
-wd4351 # Suppress 'new behavior: elements of array 'array' will be default initialized'
-wd4355 # Suppress ''this' : used in base member initializer list'
-wd4456 # Suppress 'declaration of 'var' hides local variable'
-wd4457 # Suppress 'declaration of 'var' hides function parameter'
-wd4458 # Suppress 'declaration of 'var' hides class member'
-wd4459 # Suppress 'declaration of 'var' hides global declaration'
-wd4503 # Suppress ''identifier' : decorated name length exceeded, name was truncated'
-wd4624 # Suppress ''derived class' : destructor could not be generated because a base class destructor is inaccessible'
-wd4722 # Suppress 'function' : destructor never returns, potential memory leak
-wd4800 # Suppress ''type' : forcing value to bool 'true' or 'false' (performance warning)'
-wd4100 # Suppress 'unreferenced formal parameter'
-wd4127 # Suppress 'conditional expression is constant'
-wd4512 # Suppress 'assignment operator could not be generated'
-wd4505 # Suppress 'unreferenced local function has been removed'
-wd4610 # Suppress '<class> can never be instantiated'
-wd4510 # Suppress 'default constructor could not be generated'
-wd4702 # Suppress 'unreachable code'
-wd4245 # Suppress 'signed/unsigned mismatch'
-wd4706 # Suppress 'assignment within conditional expression'
-wd4310 # Suppress 'cast truncates constant value'
-wd4701 # Suppress 'potentially uninitialized local variable'
-wd4703 # Suppress 'potentially uninitialized local pointer variable'
-wd4389 # Suppress 'signed/unsigned mismatch'
-wd4611 # Suppress 'interaction between '_setjmp' and C++ object destruction is non-portable'
-wd4805 # Suppress 'unsafe mix of type <type> and type <type> in operation'
-wd4204 # Suppress 'nonstandard extension used : non-constant aggregate initializer'
-wd4577 # Suppress 'noexcept used with no exception handling mode specified; termination on exception is not guaranteed'
-wd4091 # Suppress 'typedef: ignored on left of '' when no variable is declared'
# C4592 is disabled because of false positives in Visual Studio 2015
# Update 1. Re-evaluate the usefulness of this diagnostic with Update 2.
-wd4592 # Suppress ''var': symbol will be dynamically initialized (implementation limitation)
-wd4319 # Suppress ''operator' : zero extending 'type' to 'type' of greater size'

# Ideally, we'd like this warning to be enabled, but MSVC 2013 doesn't
# support the 'aligned' attribute in the way that clang sources requires (for
# any code that uses the LLVM_ALIGNAS macro), so this is must be disabled to
# avoid unwanted alignment warnings.
# When we switch to requiring a version of MSVC that supports the 'alignas'
# specifier (MSVC 2015?) this warning can be re-enabled.
-wd4324 # Suppress 'structure was padded due to __declspec(align())'

# Promoted warnings.
-w14062 # Promote 'enumerator in switch of enum is not handled' to level 1 warning.

# Promoted warnings to errors.
-we4238 # Promote 'nonstandard extension used : class rvalue used as lvalue' to error.
)

# Enable warnings
if (LLVM_ENABLE_WARNINGS)
# Put /W4 in front of all the -we flags. cl.exe doesn't care, but for
# clang-cl having /W4 after the -we flags will re-enable the warnings
# disabled by -we.
set(msvc_warning_flags "/W4 ${msvc_warning_flags}")
# CMake appends /W3 by default, and having /W3 followed by /W4 will result in
# cl : Command line warning D9025 : overriding '/W3' with '/W4'. Since this is
# a command line warning and not a compiler warning, it cannot be suppressed except
# by fixing the command line.
string(REGEX REPLACE " /W[0-4]" "" CMAKE_C_FLAGS "${CMAKE_C_FLAGS}")
string(REGEX REPLACE " /W[0-4]" "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")

if (LLVM_ENABLE_PEDANTIC)
# No MSVC equivalent available
endif (LLVM_ENABLE_PEDANTIC)
endif (LLVM_ENABLE_WARNINGS)
if (LLVM_ENABLE_WERROR)
append("/WX" msvc_warning_flags)
append("/WX" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
endif (LLVM_ENABLE_WERROR)

foreach(flag ${msvc_warning_flags})
append("${flag}" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
endforeach(flag)

append("/Zc:inline" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)

# /Zc:strictStrings is incompatible with VS12's (Visual Studio 2013's)
Expand Down Expand Up @@ -443,63 +364,6 @@ if( MSVC )
endif()

elseif( LLVM_COMPILER_IS_GCC_COMPATIBLE )
if (LLVM_ENABLE_WARNINGS)
append("-Wall -W -Wno-unused-parameter -Wwrite-strings" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
append("-Wcast-qual" CMAKE_CXX_FLAGS)

# Turn off missing field initializer warnings for gcc to avoid noise from
# false positives with empty {}. Turn them on otherwise (they're off by
# default for clang).
check_cxx_compiler_flag("-Wmissing-field-initializers" CXX_SUPPORTS_MISSING_FIELD_INITIALIZERS_FLAG)
if (CXX_SUPPORTS_MISSING_FIELD_INITIALIZERS_FLAG)
if (CMAKE_COMPILER_IS_GNUCXX)
append("-Wno-missing-field-initializers" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
else()
append("-Wmissing-field-initializers" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
endif()
endif()

append_if(LLVM_ENABLE_PEDANTIC "-pedantic" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
append_if(LLVM_ENABLE_PEDANTIC "-Wno-long-long" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
add_flag_if_supported("-Wcovered-switch-default" COVERED_SWITCH_DEFAULT_FLAG)
append_if(USE_NO_UNINITIALIZED "-Wno-uninitialized" CMAKE_CXX_FLAGS)
append_if(USE_NO_MAYBE_UNINITIALIZED "-Wno-maybe-uninitialized" CMAKE_CXX_FLAGS)

# Check if -Wnon-virtual-dtor warns even though the class is marked final.
# If it does, don't add it. So it won't be added on clang 3.4 and older.
# This also catches cases when -Wnon-virtual-dtor isn't supported by
# the compiler at all. This flag is not activated for gcc since it will
# incorrectly identify a protected non-virtual base when there is a friend
# declaration.
if (NOT CMAKE_COMPILER_IS_GNUCXX)
set(OLD_CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})
set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -std=c++11 -Werror=non-virtual-dtor")
CHECK_CXX_SOURCE_COMPILES("class base {public: virtual void anchor();protected: ~base();};
class derived final : public base { public: ~derived();};
int main() { return 0; }"
CXX_WONT_WARN_ON_FINAL_NONVIRTUALDTOR)
set(CMAKE_REQUIRED_FLAGS ${OLD_CMAKE_REQUIRED_FLAGS})
append_if(CXX_WONT_WARN_ON_FINAL_NONVIRTUALDTOR
"-Wnon-virtual-dtor" CMAKE_CXX_FLAGS)
endif()

# Enable -Wdelete-non-virtual-dtor if available.
add_flag_if_supported("-Wdelete-non-virtual-dtor" DELETE_NON_VIRTUAL_DTOR_FLAG)

# Check if -Wcomment is OK with an // comment ending with '\' if the next
# line is also a // comment.
set(OLD_CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})
set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -Werror -Wcomment")
CHECK_C_SOURCE_COMPILES("// \\\\\\n//\\nint main() {return 0;}"
C_WCOMMENT_ALLOWS_LINE_WRAP)
set(CMAKE_REQUIRED_FLAGS ${OLD_CMAKE_REQUIRED_FLAGS})
if (NOT C_WCOMMENT_ALLOWS_LINE_WRAP)
append("-Wno-comment" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
endif()

# Enable -Wstring-conversion to catch misuse of string literals.
add_flag_if_supported("-Wstring-conversion" STRING_CONVERSION_FLAG)
endif (LLVM_ENABLE_WARNINGS)
append_if(LLVM_ENABLE_WERROR "-Werror" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
add_flag_if_supported("-Werror=date-time" WERROR_DATE_TIME)
if (LLVM_ENABLE_CXX1Y)
Expand Down Expand Up @@ -553,6 +417,151 @@ elseif( LLVM_COMPILER_IS_GCC_COMPATIBLE )
endif(LLVM_ENABLE_MODULES)
endif( MSVC )

if (MSVC AND NOT CLANG_CL)
set(msvc_warning_flags
# Disabled warnings.
-wd4141 # Suppress ''modifier' : used more than once' (because of __forceinline combined with inline)
-wd4146 # Suppress 'unary minus operator applied to unsigned type, result still unsigned'
-wd4180 # Suppress 'qualifier applied to function type has no meaning; ignored'
-wd4244 # Suppress ''argument' : conversion from 'type1' to 'type2', possible loss of data'
-wd4258 # Suppress ''var' : definition from the for loop is ignored; the definition from the enclosing scope is used'
-wd4267 # Suppress ''var' : conversion from 'size_t' to 'type', possible loss of data'
-wd4291 # Suppress ''declaration' : no matching operator delete found; memory will not be freed if initialization throws an exception'
-wd4345 # Suppress 'behavior change: an object of POD type constructed with an initializer of the form () will be default-initialized'
-wd4351 # Suppress 'new behavior: elements of array 'array' will be default initialized'
-wd4355 # Suppress ''this' : used in base member initializer list'
-wd4456 # Suppress 'declaration of 'var' hides local variable'
-wd4457 # Suppress 'declaration of 'var' hides function parameter'
-wd4458 # Suppress 'declaration of 'var' hides class member'
-wd4459 # Suppress 'declaration of 'var' hides global declaration'
-wd4503 # Suppress ''identifier' : decorated name length exceeded, name was truncated'
-wd4624 # Suppress ''derived class' : destructor could not be generated because a base class destructor is inaccessible'
-wd4722 # Suppress 'function' : destructor never returns, potential memory leak
-wd4800 # Suppress ''type' : forcing value to bool 'true' or 'false' (performance warning)'
-wd4100 # Suppress 'unreferenced formal parameter'
-wd4127 # Suppress 'conditional expression is constant'
-wd4512 # Suppress 'assignment operator could not be generated'
-wd4505 # Suppress 'unreferenced local function has been removed'
-wd4610 # Suppress '<class> can never be instantiated'
-wd4510 # Suppress 'default constructor could not be generated'
-wd4702 # Suppress 'unreachable code'
-wd4245 # Suppress 'signed/unsigned mismatch'
-wd4706 # Suppress 'assignment within conditional expression'
-wd4310 # Suppress 'cast truncates constant value'
-wd4701 # Suppress 'potentially uninitialized local variable'
-wd4703 # Suppress 'potentially uninitialized local pointer variable'
-wd4389 # Suppress 'signed/unsigned mismatch'
-wd4611 # Suppress 'interaction between '_setjmp' and C++ object destruction is non-portable'
-wd4805 # Suppress 'unsafe mix of type <type> and type <type> in operation'
-wd4204 # Suppress 'nonstandard extension used : non-constant aggregate initializer'
-wd4577 # Suppress 'noexcept used with no exception handling mode specified; termination on exception is not guaranteed'
-wd4091 # Suppress 'typedef: ignored on left of '' when no variable is declared'
# C4592 is disabled because of false positives in Visual Studio 2015
# Update 1. Re-evaluate the usefulness of this diagnostic with Update 2.
-wd4592 # Suppress ''var': symbol will be dynamically initialized (implementation limitation)
-wd4319 # Suppress ''operator' : zero extending 'type' to 'type' of greater size'

# Ideally, we'd like this warning to be enabled, but MSVC 2013 doesn't
# support the 'aligned' attribute in the way that clang sources requires (for
# any code that uses the LLVM_ALIGNAS macro), so this is must be disabled to
# avoid unwanted alignment warnings.
# When we switch to requiring a version of MSVC that supports the 'alignas'
# specifier (MSVC 2015?) this warning can be re-enabled.
-wd4324 # Suppress 'structure was padded due to __declspec(align())'

# Promoted warnings.
-w14062 # Promote 'enumerator in switch of enum is not handled' to level 1 warning.

# Promoted warnings to errors.
-we4238 # Promote 'nonstandard extension used : class rvalue used as lvalue' to error.
)

# Enable warnings
if (LLVM_ENABLE_WARNINGS)
# Put /W4 in front of all the -we flags. cl.exe doesn't care, but for
# clang-cl having /W4 after the -we flags will re-enable the warnings
# disabled by -we.
set(msvc_warning_flags "/W4 ${msvc_warning_flags}")
# CMake appends /W3 by default, and having /W3 followed by /W4 will result in
# cl : Command line warning D9025 : overriding '/W3' with '/W4'. Since this is
# a command line warning and not a compiler warning, it cannot be suppressed except
# by fixing the command line.
string(REGEX REPLACE " /W[0-4]" "" CMAKE_C_FLAGS "${CMAKE_C_FLAGS}")
string(REGEX REPLACE " /W[0-4]" "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")

if (LLVM_ENABLE_PEDANTIC)
# No MSVC equivalent available
endif (LLVM_ENABLE_PEDANTIC)
endif (LLVM_ENABLE_WARNINGS)

foreach(flag ${msvc_warning_flags})
append("${flag}" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
endforeach(flag)
endif (MSVC AND NOT CLANG_CL)

if (LLVM_ENABLE_WARNINGS AND (LLVM_COMPILER_IS_GCC_COMPATIBLE OR CLANG_CL))
append("-Wall -W -Wno-unused-parameter -Wwrite-strings" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
append("-Wcast-qual" CMAKE_CXX_FLAGS)

# Turn off missing field initializer warnings for gcc to avoid noise from
# false positives with empty {}. Turn them on otherwise (they're off by
# default for clang).
check_cxx_compiler_flag("-Wmissing-field-initializers" CXX_SUPPORTS_MISSING_FIELD_INITIALIZERS_FLAG)
if (CXX_SUPPORTS_MISSING_FIELD_INITIALIZERS_FLAG)
if (CMAKE_COMPILER_IS_GNUCXX)
append("-Wno-missing-field-initializers" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
else()
append("-Wmissing-field-initializers" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
endif()
endif()

if (LLVM_ENABLE_PEDANTIC AND LLVM_COMPILER_IS_GCC_COMPATIBLE)
append("-pedantic" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
append("-Wno-long-long" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
endif()

add_flag_if_supported("-Wcovered-switch-default" COVERED_SWITCH_DEFAULT_FLAG)
append_if(USE_NO_UNINITIALIZED "-Wno-uninitialized" CMAKE_CXX_FLAGS)
append_if(USE_NO_MAYBE_UNINITIALIZED "-Wno-maybe-uninitialized" CMAKE_CXX_FLAGS)

# Check if -Wnon-virtual-dtor warns even though the class is marked final.
# If it does, don't add it. So it won't be added on clang 3.4 and older.
# This also catches cases when -Wnon-virtual-dtor isn't supported by
# the compiler at all. This flag is not activated for gcc since it will
# incorrectly identify a protected non-virtual base when there is a friend
# declaration. Don't activate this in general on Windows as this warning has
# too many false positives on COM-style classes, which are destroyed with
# Release() (PR32286).
if (NOT CMAKE_COMPILER_IS_GNUCXX AND NOT WIN32)
set(OLD_CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})
set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -std=c++11 -Werror=non-virtual-dtor")
CHECK_CXX_SOURCE_COMPILES("class base {public: virtual void anchor();protected: ~base();};
class derived final : public base { public: ~derived();};
int main() { return 0; }"
CXX_WONT_WARN_ON_FINAL_NONVIRTUALDTOR)
set(CMAKE_REQUIRED_FLAGS ${OLD_CMAKE_REQUIRED_FLAGS})
append_if(CXX_WONT_WARN_ON_FINAL_NONVIRTUALDTOR
"-Wnon-virtual-dtor" CMAKE_CXX_FLAGS)
endif()

# Enable -Wdelete-non-virtual-dtor if available.
add_flag_if_supported("-Wdelete-non-virtual-dtor" DELETE_NON_VIRTUAL_DTOR_FLAG)

# Check if -Wcomment is OK with an // comment ending with '\' if the next
# line is also a // comment.
set(OLD_CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})
set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -Werror -Wcomment")
CHECK_C_SOURCE_COMPILES("// \\\\\\n//\\nint main() {return 0;}"
C_WCOMMENT_ALLOWS_LINE_WRAP)
set(CMAKE_REQUIRED_FLAGS ${OLD_CMAKE_REQUIRED_FLAGS})
if (NOT C_WCOMMENT_ALLOWS_LINE_WRAP)
append("-Wno-comment" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
endif()

# Enable -Wstring-conversion to catch misuse of string literals.
add_flag_if_supported("-Wstring-conversion" STRING_CONVERSION_FLAG)
endif (LLVM_ENABLE_WARNINGS AND (LLVM_COMPILER_IS_GCC_COMPATIBLE OR CLANG_CL))

macro(append_common_sanitizer_flags)
if (NOT MSVC)
# Append -fno-omit-frame-pointer and turn on debug info to get better
Expand Down

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