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Differential D51645

[CMake] Don't use -rtlib=compiler-rt with -nodefaultlibs.
ClosedPublic

Authored by cdavis5x on Sep 4 2018, 10:45 AM.

Details

Reviewers
mstorsjo
rnk
beanz
Commits
rG4c08654b1711: [CMake] Don't use -rtlib=compiler-rt with -nodefaultlibs.
rL341404: [CMake] Don't use -rtlib=compiler-rt with -nodefaultlibs.
rUNW341404: [CMake] Don't use -rtlib=compiler-rt with -nodefaultlibs.
Summary

This switch only has an effect at link time. It changes the default
compiler support library to compiler-rt. With -nodefaultlibs, this
library won't get linked anyway; Clang actually warns about that.

Diff Detail

Event Timeline

cdavis5x created this revision.Sep 4 2018, 10:45 AM
Herald added subscribers: cfe-commits, christof, mgorny, dberris. · View Herald TranscriptSep 4 2018, 10:45 AM
Harbormaster completed remote builds in B22219: Diff 163864.Sep 4 2018, 10:45 AM
mstorsjo added a subscriber: beanz.Sep 4 2018, 12:22 PM

Sounds sensible to me, although it might be good with a second opinion I think. @beanz?

cdavis5x added a reviewer: beanz.Sep 4 2018, 12:35 PM
beanz accepted this revision.Sep 4 2018, 1:58 PM

LGTM.

This revision is now accepted and ready to land.Sep 4 2018, 1:58 PM
Closed by commit rUNW341404: [CMake] Don't use -rtlib=compiler-rt with -nodefaultlibs. (authored by cdavis). · Explain WhySep 4 2018, 1:58 PM
This revision was automatically updated to reflect the committed changes.

Revision Contents

PathSize
2 lines
cmake/
1 line

Diff 163864

CMakeLists.txt

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if (LIBUNWIND_TARGET_TRIPLE) if (LIBUNWIND_TARGET_TRIPLE)
set(TARGET_TRIPLE "${LIBUNWIND_TARGET_TRIPLE}") set(TARGET_TRIPLE "${LIBUNWIND_TARGET_TRIPLE}")
endif() endif()
# Configure compiler. # Configure compiler.
include(config-ix) include(config-ix)
if (LIBUNWIND_USE_COMPILER_RT) if (LIBUNWIND_USE_COMPILER_RT AND NOT LIBUNWIND_HAS_NODEFAULTLIBS_FLAG)
list(APPEND LIBUNWIND_LINK_FLAGS "-rtlib=compiler-rt") list(APPEND LIBUNWIND_LINK_FLAGS "-rtlib=compiler-rt")
endif() endif()
#=============================================================================== #===============================================================================
# Setup Compiler Flags # Setup Compiler Flags
#=============================================================================== #===============================================================================
append_if(LIBUNWIND_COMPILE_FLAGS LIBUNWIND_HAS_WERROR_FLAG -Werror=return-type) append_if(LIBUNWIND_COMPILE_FLAGS LIBUNWIND_HAS_WERROR_FLAG -Werror=return-type)
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cmake/config-ix.cmake

Show All 17 Lines
# configuration checks to avoid spurious link errors. # configuration checks to avoid spurious link errors.
check_c_compiler_flag(-nodefaultlibs LIBUNWIND_HAS_NODEFAULTLIBS_FLAG) check_c_compiler_flag(-nodefaultlibs LIBUNWIND_HAS_NODEFAULTLIBS_FLAG)
if (LIBUNWIND_HAS_NODEFAULTLIBS_FLAG) if (LIBUNWIND_HAS_NODEFAULTLIBS_FLAG)
set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -nodefaultlibs") set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -nodefaultlibs")
if (LIBUNWIND_HAS_C_LIB) if (LIBUNWIND_HAS_C_LIB)
list(APPEND CMAKE_REQUIRED_LIBRARIES c) list(APPEND CMAKE_REQUIRED_LIBRARIES c)
endif () endif ()
if (LIBUNWIND_USE_COMPILER_RT) if (LIBUNWIND_USE_COMPILER_RT)
list(APPEND CMAKE_REQUIRED_FLAGS -rtlib=compiler-rt)
find_compiler_rt_library(builtins LIBUNWIND_BUILTINS_LIBRARY) find_compiler_rt_library(builtins LIBUNWIND_BUILTINS_LIBRARY)
list(APPEND CMAKE_REQUIRED_LIBRARIES "${LIBUNWIND_BUILTINS_LIBRARY}") list(APPEND CMAKE_REQUIRED_LIBRARIES "${LIBUNWIND_BUILTINS_LIBRARY}")
elseif (LIBUNWIND_HAS_GCC_S_LIB) elseif (LIBUNWIND_HAS_GCC_S_LIB)
list(APPEND CMAKE_REQUIRED_LIBRARIES gcc_s) list(APPEND CMAKE_REQUIRED_LIBRARIES gcc_s)
endif () endif ()
if (MINGW) if (MINGW)
# Mingw64 requires quite a few "C" runtime libraries in order for basic # Mingw64 requires quite a few "C" runtime libraries in order for basic
# programs to link successfully with -nodefaultlibs. # programs to link successfully with -nodefaultlibs.
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