1# This CMake module is responsible for interpreting the user defined LLVM_
2# options and executing the appropriate CMake commands to realize the users'
3# selections.
4
5# This is commonly needed so make sure it's defined before we include anything
6# else.
7string(TOUPPER "${CMAKE_BUILD_TYPE}" uppercase_CMAKE_BUILD_TYPE)
8
9include(HandleLLVMStdlib)
10include(AddLLVMDefinitions)
11include(CheckCCompilerFlag)
12include(CheckCXXCompilerFlag)
13
14if(NOT LLVM_FORCE_USE_OLD_TOOLCHAIN)
15  if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
16    if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.7)
17      message(FATAL_ERROR "Host GCC version must be at least 4.7!")
18    endif()
19  elseif(CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
20    if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS 3.1)
21      message(FATAL_ERROR "Host Clang version must be at least 3.1!")
22    endif()
23
24    if (CMAKE_CXX_SIMULATE_ID MATCHES "MSVC")
25      if (CMAKE_CXX_SIMULATE_VERSION VERSION_LESS 18.0)
26        message(FATAL_ERROR "Host Clang must have at least -fms-compatibility-version=18.0")
27      endif()
28      set(CLANG_CL 1)
29    elseif(NOT LLVM_ENABLE_LIBCXX)
30      # Otherwise, test that we aren't using too old of a version of libstdc++
31      # with the Clang compiler. This is tricky as there is no real way to
32      # check the version of libstdc++ directly. Instead we test for a known
33      # bug in libstdc++4.6 that is fixed in libstdc++4.7.
34      set(OLD_CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})
35      set(OLD_CMAKE_REQUIRED_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES})
36      set(CMAKE_REQUIRED_FLAGS "-std=c++0x")
37      check_cxx_source_compiles("
38#include <atomic>
39std::atomic<float> x(0.0f);
40int main() { return (float)x; }"
41        LLVM_NO_OLD_LIBSTDCXX)
42      if(NOT LLVM_NO_OLD_LIBSTDCXX)
43        message(FATAL_ERROR "Host Clang must be able to find libstdc++4.7 or newer!")
44      endif()
45      set(CMAKE_REQUIRED_FLAGS ${OLD_CMAKE_REQUIRED_FLAGS})
46      set(CMAKE_REQUIRED_LIBRARIES ${OLD_CMAKE_REQUIRED_LIBRARIES})
47    endif()
48  elseif(CMAKE_CXX_COMPILER_ID MATCHES "MSVC")
49    if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS 18.0)
50      message(FATAL_ERROR "Host Visual Studio must be at least 2013")
51    elseif(CMAKE_CXX_COMPILER_VERSION VERSION_LESS 18.0.31101)
52      message(WARNING "Host Visual Studio should at least be 2013 Update 4 (MSVC 18.0.31101)"
53        "  due to miscompiles from earlier versions")
54    endif()
55  endif()
56endif()
57
58if( LLVM_ENABLE_ASSERTIONS )
59  # MSVC doesn't like _DEBUG on release builds. See PR 4379.
60  if( NOT MSVC )
61    add_definitions( -D_DEBUG )
62  endif()
63  # On non-Debug builds cmake automatically defines NDEBUG, so we
64  # explicitly undefine it:
65  if( NOT uppercase_CMAKE_BUILD_TYPE STREQUAL "DEBUG" )
66    add_definitions( -UNDEBUG )
67    # Also remove /D NDEBUG to avoid MSVC warnings about conflicting defines.
68    foreach (flags_var_to_scrub
69        CMAKE_CXX_FLAGS_RELEASE
70        CMAKE_CXX_FLAGS_RELWITHDEBINFO
71        CMAKE_CXX_FLAGS_MINSIZEREL
72        CMAKE_C_FLAGS_RELEASE
73        CMAKE_C_FLAGS_RELWITHDEBINFO
74        CMAKE_C_FLAGS_MINSIZEREL)
75      string (REGEX REPLACE "(^| )[/-]D *NDEBUG($| )" " "
76        "${flags_var_to_scrub}" "${${flags_var_to_scrub}}")
77    endforeach()
78  endif()
79endif()
80
81string(TOUPPER "${LLVM_ABI_BREAKING_CHECKS}" uppercase_LLVM_ABI_BREAKING_CHECKS)
82
83if( uppercase_LLVM_ABI_BREAKING_CHECKS STREQUAL "WITH_ASSERTS" )
84  if( LLVM_ENABLE_ASSERTIONS )
85    set( LLVM_ENABLE_ABI_BREAKING_CHECKS 1 )
86  endif()
87elseif( uppercase_LLVM_ABI_BREAKING_CHECKS STREQUAL "FORCE_ON" )
88  set( LLVM_ENABLE_ABI_BREAKING_CHECKS 1 )
89elseif( uppercase_LLVM_ABI_BREAKING_CHECKS STREQUAL "FORCE_OFF" )
90  # We don't need to do anything special to turn off ABI breaking checks.
91else()
92  message(FATAL_ERROR "Unknown value for LLVM_ABI_BREAKING_CHECKS: \"${LLVM_ABI_BREAKING_CHECKS}\"!")
93endif()
94
95if(WIN32)
96  set(LLVM_HAVE_LINK_VERSION_SCRIPT 0)
97  if(CYGWIN)
98    set(LLVM_ON_WIN32 0)
99    set(LLVM_ON_UNIX 1)
100  else(CYGWIN)
101    set(LLVM_ON_WIN32 1)
102    set(LLVM_ON_UNIX 0)
103  endif(CYGWIN)
104else(WIN32)
105  if(UNIX)
106    set(LLVM_ON_WIN32 0)
107    set(LLVM_ON_UNIX 1)
108    if(APPLE)
109      set(LLVM_HAVE_LINK_VERSION_SCRIPT 0)
110    else(APPLE)
111      set(LLVM_HAVE_LINK_VERSION_SCRIPT 1)
112    endif(APPLE)
113  else(UNIX)
114    MESSAGE(SEND_ERROR "Unable to determine platform")
115  endif(UNIX)
116endif(WIN32)
117
118set(EXEEXT ${CMAKE_EXECUTABLE_SUFFIX})
119set(LTDL_SHLIB_EXT ${CMAKE_SHARED_LIBRARY_SUFFIX})
120
121# We use *.dylib rather than *.so on darwin.
122set(LLVM_PLUGIN_EXT ${CMAKE_SHARED_LIBRARY_SUFFIX})
123
124if(APPLE)
125  # Darwin-specific linker flags for loadable modules.
126  set(CMAKE_MODULE_LINKER_FLAGS "${CMAKE_MODULE_LINKER_FLAGS} -Wl,-flat_namespace -Wl,-undefined -Wl,suppress")
127endif()
128
129# Pass -Wl,-z,defs. This makes sure all symbols are defined. Otherwise a DSO
130# build might work on ELF but fail on MachO/COFF.
131if(NOT (${CMAKE_SYSTEM_NAME} MATCHES "Darwin" OR WIN32 OR
132        ${CMAKE_SYSTEM_NAME} MATCHES "FreeBSD") AND
133   NOT LLVM_USE_SANITIZER)
134  set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} -Wl,-z,defs")
135endif()
136
137
138function(append value)
139  foreach(variable ${ARGN})
140    set(${variable} "${${variable}} ${value}" PARENT_SCOPE)
141  endforeach(variable)
142endfunction()
143
144function(append_if condition value)
145  if (${condition})
146    foreach(variable ${ARGN})
147      set(${variable} "${${variable}} ${value}" PARENT_SCOPE)
148    endforeach(variable)
149  endif()
150endfunction()
151
152macro(add_flag_if_supported flag name)
153  check_c_compiler_flag("-Werror ${flag}" "C_SUPPORTS_${name}")
154  append_if("C_SUPPORTS_${name}" "${flag}" CMAKE_C_FLAGS)
155  check_cxx_compiler_flag("-Werror ${flag}" "CXX_SUPPORTS_${name}")
156  append_if("CXX_SUPPORTS_${name}" "${flag}" CMAKE_CXX_FLAGS)
157endmacro()
158
159function(add_flag_or_print_warning flag name)
160  check_c_compiler_flag("-Werror ${flag}" "C_SUPPORTS_${name}")
161  check_cxx_compiler_flag("-Werror ${flag}" "CXX_SUPPORTS_${name}")
162  if (C_SUPPORTS_${name} AND CXX_SUPPORTS_${name})
163    message(STATUS "Building with ${flag}")
164    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${flag}" PARENT_SCOPE)
165    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${flag}" PARENT_SCOPE)
166  else()
167    message(WARNING "${flag} is not supported.")
168  endif()
169endfunction()
170
171if( LLVM_ENABLE_PIC )
172  if( XCODE )
173    # Xcode has -mdynamic-no-pic on by default, which overrides -fPIC. I don't
174    # know how to disable this, so just force ENABLE_PIC off for now.
175    message(WARNING "-fPIC not supported with Xcode.")
176  elseif( WIN32 OR CYGWIN)
177    # On Windows all code is PIC. MinGW warns if -fPIC is used.
178  else()
179    add_flag_or_print_warning("-fPIC" FPIC)
180
181    if( WIN32 OR CYGWIN)
182      # MinGW warns if -fvisibility-inlines-hidden is used.
183    else()
184      check_cxx_compiler_flag("-fvisibility-inlines-hidden" SUPPORTS_FVISIBILITY_INLINES_HIDDEN_FLAG)
185      append_if(SUPPORTS_FVISIBILITY_INLINES_HIDDEN_FLAG "-fvisibility-inlines-hidden" CMAKE_CXX_FLAGS)
186    endif()
187  endif()
188endif()
189
190if( CMAKE_SIZEOF_VOID_P EQUAL 8 AND NOT WIN32 )
191  # TODO: support other platforms and toolchains.
192  if( LLVM_BUILD_32_BITS )
193    message(STATUS "Building 32 bits executables and libraries.")
194    add_llvm_definitions( -m32 )
195    set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -m32")
196    set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} -m32")
197    set(CMAKE_MODULE_LINKER_FLAGS "${CMAKE_MODULE_LINKER_FLAGS} -m32")
198  endif( LLVM_BUILD_32_BITS )
199endif( CMAKE_SIZEOF_VOID_P EQUAL 8 AND NOT WIN32 )
200
201if (LLVM_BUILD_STATIC)
202  set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -static")
203endif()
204
205if( XCODE )
206  # For Xcode enable several build settings that correspond to
207  # many warnings that are on by default in Clang but are
208  # not enabled for historical reasons.  For versions of Xcode
209  # that do not support these options they will simply
210  # be ignored.
211  set(CMAKE_XCODE_ATTRIBUTE_GCC_WARN_ABOUT_RETURN_TYPE "YES")
212  set(CMAKE_XCODE_ATTRIBUTE_GCC_WARN_ABOUT_MISSING_NEWLINE "YES")
213  set(CMAKE_XCODE_ATTRIBUTE_GCC_WARN_UNUSED_VALUE "YES")
214  set(CMAKE_XCODE_ATTRIBUTE_GCC_WARN_UNUSED_VARIABLE "YES")
215  set(CMAKE_XCODE_ATTRIBUTE_GCC_WARN_SIGN_COMPARE "YES")
216  set(CMAKE_XCODE_ATTRIBUTE_GCC_WARN_UNUSED_FUNCTION "YES")
217  set(CMAKE_XCODE_ATTRIBUTE_GCC_WARN_INITIALIZER_NOT_FULLY_BRACKETED "YES")
218  set(CMAKE_XCODE_ATTRIBUTE_GCC_WARN_HIDDEN_VIRTUAL_FUNCTIONS "YES")
219  set(CMAKE_XCODE_ATTRIBUTE_GCC_WARN_UNINITIALIZED_AUTOS "YES")
220  set(CMAKE_XCODE_ATTRIBUTE_CLANG_WARN_BOOL_CONVERSION "YES")
221  set(CMAKE_XCODE_ATTRIBUTE_CLANG_WARN_EMPTY_BODY "YES")
222  set(CMAKE_XCODE_ATTRIBUTE_CLANG_WARN_ENUM_CONVERSION "YES")
223  set(CMAKE_XCODE_ATTRIBUTE_CLANG_WARN_INT_CONVERSION "YES")
224  set(CMAKE_XCODE_ATTRIBUTE_CLANG_WARN_CONSTANT_CONVERSION "YES")
225  set(CMAKE_XCODE_ATTRIBUTE_GCC_WARN_NON_VIRTUAL_DESTRUCTOR "YES")
226endif()
227
228# On Win32 using MS tools, provide an option to set the number of parallel jobs
229# to use.
230if( MSVC_IDE )
231  set(LLVM_COMPILER_JOBS "0" CACHE STRING
232    "Number of parallel compiler jobs. 0 means use all processors. Default is 0.")
233  if( NOT LLVM_COMPILER_JOBS STREQUAL "1" )
234    if( LLVM_COMPILER_JOBS STREQUAL "0" )
235      add_llvm_definitions( /MP )
236    else()
237      message(STATUS "Number of parallel compiler jobs set to " ${LLVM_COMPILER_JOBS})
238      add_llvm_definitions( /MP${LLVM_COMPILER_JOBS} )
239    endif()
240  else()
241    message(STATUS "Parallel compilation disabled")
242  endif()
243endif()
244
245if( MSVC )
246  include(ChooseMSVCCRT)
247
248  if( NOT (${CMAKE_VERSION} VERSION_LESS 2.8.11) )
249    # set stack reserved size to ~10MB
250    # CMake previously automatically set this value for MSVC builds, but the
251    # behavior was changed in CMake 2.8.11 (Issue 12437) to use the MSVC default
252    # value (1 MB) which is not enough for us in tasks such as parsing recursive
253    # C++ templates in Clang.
254    set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} /STACK:10000000")
255  endif()
256
257  if( MSVC11 )
258    add_llvm_definitions(-D_VARIADIC_MAX=10)
259  endif()
260
261  # Add definitions that make MSVC much less annoying.
262  add_llvm_definitions(
263    # For some reason MS wants to deprecate a bunch of standard functions...
264    -D_CRT_SECURE_NO_DEPRECATE
265    -D_CRT_SECURE_NO_WARNINGS
266    -D_CRT_NONSTDC_NO_DEPRECATE
267    -D_CRT_NONSTDC_NO_WARNINGS
268    -D_SCL_SECURE_NO_DEPRECATE
269    -D_SCL_SECURE_NO_WARNINGS
270    )
271
272  set(msvc_warning_flags
273    # Disabled warnings.
274    -wd4146 # Suppress 'unary minus operator applied to unsigned type, result still unsigned'
275    -wd4180 # Suppress 'qualifier applied to function type has no meaning; ignored'
276    -wd4244 # Suppress ''argument' : conversion from 'type1' to 'type2', possible loss of data'
277    -wd4258 # Suppress ''var' : definition from the for loop is ignored; the definition from the enclosing scope is used'
278    -wd4267 # Suppress ''var' : conversion from 'size_t' to 'type', possible loss of data'
279    -wd4291 # Suppress ''declaration' : no matching operator delete found; memory will not be freed if initialization throws an exception'
280    -wd4345 # Suppress 'behavior change: an object of POD type constructed with an initializer of the form () will be default-initialized'
281    -wd4351 # Suppress 'new behavior: elements of array 'array' will be default initialized'
282    -wd4355 # Suppress ''this' : used in base member initializer list'
283    -wd4456 # Suppress 'declaration of 'var' hides local variable'
284    -wd4457 # Suppress 'declaration of 'var' hides function parameter'
285    -wd4458 # Suppress 'declaration of 'var' hides class member'
286    -wd4459 # Suppress 'declaration of 'var' hides global declaration'
287    -wd4503 # Suppress ''identifier' : decorated name length exceeded, name was truncated'
288    -wd4624 # Suppress ''derived class' : destructor could not be generated because a base class destructor is inaccessible'
289    -wd4722 # Suppress 'function' : destructor never returns, potential memory leak
290    -wd4800 # Suppress ''type' : forcing value to bool 'true' or 'false' (performance warning)'
291    -wd4100 # Suppress 'unreferenced formal parameter'
292    -wd4127 # Suppress 'conditional expression is constant'
293    -wd4512 # Suppress 'assignment operator could not be generated'
294    -wd4505 # Suppress 'unreferenced local function has been removed'
295    -wd4610 # Suppress '<class> can never be instantiated'
296    -wd4510 # Suppress 'default constructor could not be generated'
297    -wd4702 # Suppress 'unreachable code'
298    -wd4245 # Suppress 'signed/unsigned mismatch'
299    -wd4706 # Suppress 'assignment within conditional expression'
300    -wd4310 # Suppress 'cast truncates constant value'
301    -wd4701 # Suppress 'potentially uninitialized local variable'
302    -wd4703 # Suppress 'potentially uninitialized local pointer variable'
303    -wd4389 # Suppress 'signed/unsigned mismatch'
304    -wd4611 # Suppress 'interaction between '_setjmp' and C++ object destruction is non-portable'
305    -wd4805 # Suppress 'unsafe mix of type <type> and type <type> in operation'
306    -wd4204 # Suppress 'nonstandard extension used : non-constant aggregate initializer'
307
308    # Promoted warnings.
309    -w14062 # Promote 'enumerator in switch of enum is not handled' to level 1 warning.
310
311    # Promoted warnings to errors.
312    -we4238 # Promote 'nonstandard extension used : class rvalue used as lvalue' to error.
313    )
314
315  # Enable warnings
316  if (LLVM_ENABLE_WARNINGS)
317    append("/W4" msvc_warning_flags)
318    # CMake appends /W3 by default, and having /W3 followed by /W4 will result in
319    # cl : Command line warning D9025 : overriding '/W3' with '/W4'.  Since this is
320    # a command line warning and not a compiler warning, it cannot be suppressed except
321    # by fixing the command line.
322    string(REGEX REPLACE " /W[0-4]" "" CMAKE_C_FLAGS "${CMAKE_C_FLAGS}")
323    string(REGEX REPLACE " /W[0-4]" "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
324
325    if (LLVM_ENABLE_PEDANTIC)
326      # No MSVC equivalent available
327    endif (LLVM_ENABLE_PEDANTIC)
328  endif (LLVM_ENABLE_WARNINGS)
329  if (LLVM_ENABLE_WERROR)
330    append("/WX" msvc_warning_flags)
331  endif (LLVM_ENABLE_WERROR)
332
333  foreach(flag ${msvc_warning_flags})
334    append("${flag}" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
335  endforeach(flag)
336
337elseif( LLVM_COMPILER_IS_GCC_COMPATIBLE )
338  if (LLVM_ENABLE_WARNINGS)
339    append("-Wall -W -Wno-unused-parameter -Wwrite-strings" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
340    append("-Wcast-qual" CMAKE_CXX_FLAGS)
341
342    # Turn off missing field initializer warnings for gcc to avoid noise from
343    # false positives with empty {}. Turn them on otherwise (they're off by
344    # default for clang).
345    check_cxx_compiler_flag("-Wmissing-field-initializers" CXX_SUPPORTS_MISSING_FIELD_INITIALIZERS_FLAG)
346    if (CXX_SUPPORTS_MISSING_FIELD_INITIALIZERS_FLAG)
347      if (CMAKE_COMPILER_IS_GNUCXX)
348        append("-Wno-missing-field-initializers" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
349      else()
350        append("-Wmissing-field-initializers" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
351      endif()
352    endif()
353
354    append_if(LLVM_ENABLE_PEDANTIC "-pedantic -Wno-long-long" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
355    add_flag_if_supported("-Wcovered-switch-default" COVERED_SWITCH_DEFAULT_FLAG)
356    append_if(USE_NO_UNINITIALIZED "-Wno-uninitialized" CMAKE_CXX_FLAGS)
357    append_if(USE_NO_MAYBE_UNINITIALIZED "-Wno-maybe-uninitialized" CMAKE_CXX_FLAGS)
358
359    # Check if -Wnon-virtual-dtor warns even though the class is marked final.
360    # If it does, don't add it. So it won't be added on clang 3.4 and older.
361    # This also catches cases when -Wnon-virtual-dtor isn't supported by
362    # the compiler at all.
363    set(OLD_CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})
364    set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -std=c++11 -Werror=non-virtual-dtor")
365    CHECK_CXX_SOURCE_COMPILES("class base {public: virtual void anchor();protected: ~base();};
366                               class derived final : public base { public: ~derived();};
367                               int main() { return 0; }"
368                              CXX_WONT_WARN_ON_FINAL_NONVIRTUALDTOR)
369    set(CMAKE_REQUIRED_FLAGS ${OLD_CMAKE_REQUIRED_FLAGS})
370    append_if(CXX_WONT_WARN_ON_FINAL_NONVIRTUALDTOR
371              "-Wnon-virtual-dtor" CMAKE_CXX_FLAGS)
372
373    # Check if -Wcomment is OK with an // comment ending with '\' if the next
374    # line is also a // comment.
375    set(OLD_CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})
376    set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -Werror -Wcomment")
377    CHECK_C_SOURCE_COMPILES("// \\\\\\n//\\nint main() {return 0;}"
378                            C_WCOMMENT_ALLOWS_LINE_WRAP)
379    set(CMAKE_REQUIRED_FLAGS ${OLD_CMAKE_REQUIRED_FLAGS})
380    if (NOT C_WCOMMENT_ALLOWS_LINE_WRAP)
381      append("-Wno-comment" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
382    endif()
383  endif (LLVM_ENABLE_WARNINGS)
384  append_if(LLVM_ENABLE_WERROR "-Werror" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
385  if (NOT LLVM_ENABLE_TIMESTAMPS)
386    add_flag_if_supported("-Werror=date-time" WERROR_DATE_TIME)
387  endif ()
388  if (LLVM_ENABLE_CXX1Y)
389    check_cxx_compiler_flag("-std=c++1y" CXX_SUPPORTS_CXX1Y)
390    append_if(CXX_SUPPORTS_CXX1Y "-std=c++1y" CMAKE_CXX_FLAGS)
391  else()
392    check_cxx_compiler_flag("-std=c++11" CXX_SUPPORTS_CXX11)
393    if (CXX_SUPPORTS_CXX11)
394      if (CYGWIN OR MINGW)
395        # MinGW and Cygwin are a bit stricter and lack things like
396        # 'strdup', 'stricmp', etc in c++11 mode.
397        append("-std=gnu++11" CMAKE_CXX_FLAGS)
398      else()
399        append("-std=c++11" CMAKE_CXX_FLAGS)
400      endif()
401    else()
402      message(FATAL_ERROR "LLVM requires C++11 support but the '-std=c++11' flag isn't supported.")
403    endif()
404  endif()
405  if (LLVM_ENABLE_MODULES)
406    set(OLD_CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})
407    set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -fmodules -fcxx-modules")
408    # Check that we can build code with modules enabled, and that repeatedly
409    # including <cassert> still manages to respect NDEBUG properly.
410    CHECK_CXX_SOURCE_COMPILES("#undef NDEBUG
411                               #include <cassert>
412                               #define NDEBUG
413                               #include <cassert>
414                               int main() { assert(this code is not compiled); }"
415                               CXX_SUPPORTS_MODULES)
416    set(CMAKE_REQUIRED_FLAGS ${OLD_CMAKE_REQUIRED_FLAGS})
417    if (CXX_SUPPORTS_MODULES)
418      append_if(CXX_SUPPORTS_MODULES "-fmodules" CMAKE_C_FLAGS)
419      append_if(CXX_SUPPORTS_MODULES "-fmodules -fcxx-modules" CMAKE_CXX_FLAGS)
420    else()
421      message(FATAL_ERROR "LLVM_ENABLE_MODULES is not supported by this compiler")
422    endif()
423  endif(LLVM_ENABLE_MODULES)
424endif( MSVC )
425
426macro(append_common_sanitizer_flags)
427  # Append -fno-omit-frame-pointer and turn on debug info to get better
428  # stack traces.
429  add_flag_if_supported("-fno-omit-frame-pointer" FNO_OMIT_FRAME_POINTER)
430  if (NOT uppercase_CMAKE_BUILD_TYPE STREQUAL "DEBUG" AND
431      NOT uppercase_CMAKE_BUILD_TYPE STREQUAL "RELWITHDEBINFO")
432    add_flag_if_supported("-gline-tables-only" GLINE_TABLES_ONLY)
433  endif()
434  # Use -O1 even in debug mode, otherwise sanitizers slowdown is too large.
435  if (uppercase_CMAKE_BUILD_TYPE STREQUAL "DEBUG")
436    add_flag_if_supported("-O1" O1)
437  endif()
438endmacro()
439
440# Turn on sanitizers if necessary.
441if(LLVM_USE_SANITIZER)
442  if (LLVM_ON_UNIX)
443    if (LLVM_USE_SANITIZER STREQUAL "Address")
444      append_common_sanitizer_flags()
445      append("-fsanitize=address" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
446    elseif (LLVM_USE_SANITIZER MATCHES "Memory(WithOrigins)?")
447      append_common_sanitizer_flags()
448      append("-fsanitize=memory" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
449      if(LLVM_USE_SANITIZER STREQUAL "MemoryWithOrigins")
450        append("-fsanitize-memory-track-origins" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
451      endif()
452    elseif (LLVM_USE_SANITIZER STREQUAL "Undefined")
453      append_common_sanitizer_flags()
454      append("-fsanitize=undefined -fno-sanitize=vptr,function -fno-sanitize-recover"
455              CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
456    elseif (LLVM_USE_SANITIZER STREQUAL "Thread")
457      append_common_sanitizer_flags()
458      append("-fsanitize=thread" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
459    elseif (LLVM_USE_SANITIZER STREQUAL "Address;Undefined" OR
460            LLVM_USE_SANITIZER STREQUAL "Undefined;Address")
461      append_common_sanitizer_flags()
462      append("-fsanitize=address,undefined -fno-sanitize=vptr,function -fno-sanitize-recover"
463              CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
464    else()
465      message(WARNING "Unsupported value of LLVM_USE_SANITIZER: ${LLVM_USE_SANITIZER}")
466    endif()
467  else()
468    message(WARNING "LLVM_USE_SANITIZER is not supported on this platform.")
469  endif()
470  if (LLVM_USE_SANITIZE_COVERAGE)
471    append("-fsanitize-coverage=4 -mllvm -sanitizer-coverage-8bit-counters=1" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
472  endif()
473endif()
474
475# Turn on -gsplit-dwarf if requested
476if(LLVM_USE_SPLIT_DWARF)
477  add_definitions("-gsplit-dwarf")
478endif()
479
480add_llvm_definitions( -D__STDC_CONSTANT_MACROS )
481add_llvm_definitions( -D__STDC_FORMAT_MACROS )
482add_llvm_definitions( -D__STDC_LIMIT_MACROS )
483
484# clang doesn't print colored diagnostics when invoked from Ninja
485if (UNIX AND
486    CMAKE_CXX_COMPILER_ID STREQUAL "Clang" AND
487    CMAKE_GENERATOR STREQUAL "Ninja")
488  append("-fcolor-diagnostics" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
489endif()
490
491# Add flags for add_dead_strip().
492# FIXME: With MSVS, consider compiling with /Gy and linking with /OPT:REF?
493# But MinSizeRel seems to add that automatically, so maybe disable these
494# flags instead if LLVM_NO_DEAD_STRIP is set.
495if(NOT CYGWIN AND NOT WIN32)
496  if(NOT ${CMAKE_SYSTEM_NAME} MATCHES "Darwin" AND
497     NOT uppercase_CMAKE_BUILD_TYPE STREQUAL "DEBUG")
498    check_c_compiler_flag("-Werror -fno-function-sections" C_SUPPORTS_FNO_FUNCTION_SECTIONS)
499    if (C_SUPPORTS_FNO_FUNCTION_SECTIONS)
500      # Don't add -ffunction-section if it can be disabled with -fno-function-sections.
501      # Doing so will break sanitizers.
502      add_flag_if_supported("-ffunction-sections" FFUNCTION_SECTIONS)
503    endif()
504    add_flag_if_supported("-fdata-sections" FDATA_SECTIONS)
505  endif()
506endif()
507
508if(CYGWIN OR MINGW)
509  # Prune --out-implib from executables. It doesn't make sense even
510  # with --export-all-symbols.
511  string(REGEX REPLACE "-Wl,--out-implib,[^ ]+ " " "
512    CMAKE_C_LINK_EXECUTABLE "${CMAKE_C_LINK_EXECUTABLE}")
513  string(REGEX REPLACE "-Wl,--out-implib,[^ ]+ " " "
514    CMAKE_CXX_LINK_EXECUTABLE "${CMAKE_CXX_LINK_EXECUTABLE}")
515endif()
516
517if(MSVC)
518  # Remove flags here, for exceptions and RTTI.
519  # Each target property or source property should be responsible to control
520  # them.
521  # CL.EXE complains to override flags like "/GR /GR-".
522  string(REGEX REPLACE "(^| ) */EH[-cs]+ *( |$)" "\\1 \\2" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
523  string(REGEX REPLACE "(^| ) */GR-? *( |$)" "\\1 \\2" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
524endif()
525
526# Provide public options to globally control RTTI and EH
527option(LLVM_ENABLE_EH "Enable Exception handling" OFF)
528option(LLVM_ENABLE_RTTI "Enable run time type information" OFF)
529if(LLVM_ENABLE_EH AND NOT LLVM_ENABLE_RTTI)
530  message(FATAL_ERROR "Exception handling requires RTTI. You must set LLVM_ENABLE_RTTI to ON")
531endif()
532
533# Plugin support
534# FIXME: Make this configurable.
535if(WIN32 OR CYGWIN)
536  if(BUILD_SHARED_LIBS)
537    set(LLVM_ENABLE_PLUGINS ON)
538  else()
539    set(LLVM_ENABLE_PLUGINS OFF)
540  endif()
541else()
542  set(LLVM_ENABLE_PLUGINS ON)
543endif()
544