[Clang][Cygwin] Disable shared libs on Cygwin by default #138119
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This change follows MinGW decisions, otherwise build with GCC fail with: ``` FAILED: bin/msys-clang-cpp-21.0git.dll lib/libclang-cpp.dll.a ... /usr/lib/gcc/x86_64-pc-msys/13.3.0/../../../../x86_64-pc-msys/bin/ld: error: export ordinal too large: 92250 ``` Co-authored-by: jeremyd2019 <[email protected]>
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@llvm/pr-subscribers-clang Author: Mateusz Mikuła (mati865) ChangesThis change follows MinGW decisions, otherwise build with GCC fail with: Split out from #134494 Full diff: https://github.com/llvm/llvm-project/pull/138119.diff 2 Files Affected:
diff --git a/clang/tools/CMakeLists.txt b/clang/tools/CMakeLists.txt
index 9634eb12080c8..50e3d694236ac 100644
--- a/clang/tools/CMakeLists.txt
+++ b/clang/tools/CMakeLists.txt
@@ -26,9 +26,10 @@ endif()
add_clang_subdirectory(c-index-test)
add_clang_subdirectory(clang-refactor)
-# For MinGW we only enable shared library if LLVM_LINK_LLVM_DYLIB=ON.
+# For MinGW/Cygwin we only enable shared library if LLVM_LINK_LLVM_DYLIB=ON.
# Without that option resulting library is too close to 2^16 DLL exports limit.
-if(UNIX OR (MSVC AND LLVM_BUILD_LLVM_DYLIB_VIS) OR (MINGW AND LLVM_LINK_LLVM_DYLIB))
+if((UNIX AND NOT CYGWIN) OR (MSVC AND LLVM_BUILD_LLVM_DYLIB_VIS) OR
+ ((MINGW OR CYGWIN) AND LLVM_LINK_LLVM_DYLIB))
add_clang_subdirectory(clang-shlib)
endif()
diff --git a/clang/tools/libclang/CMakeLists.txt b/clang/tools/libclang/CMakeLists.txt
index 299c14660f3d4..37a939ffcada7 100644
--- a/clang/tools/libclang/CMakeLists.txt
+++ b/clang/tools/libclang/CMakeLists.txt
@@ -106,7 +106,8 @@ if (LLVM_EXPORTED_SYMBOL_FILE)
DEPENDS ${LIBCLANG_VERSION_SCRIPT_FILE})
endif()
-if(LLVM_ENABLE_PIC OR (WIN32 AND NOT LIBCLANG_BUILD_STATIC))
+if((NOT (WIN32 OR CYGWIN) AND LLVM_ENABLE_PIC) OR
+ ((WIN32 OR CYGWIN) AND NOT LIBCLANG_BUILD_STATIC))
set(ENABLE_SHARED SHARED)
endif()
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| @@ -106,7 +106,8 @@ if (LLVM_EXPORTED_SYMBOL_FILE) | |||
| DEPENDS ${LIBCLANG_VERSION_SCRIPT_FILE}) | |||
| endif() | |||
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| if(LLVM_ENABLE_PIC OR (WIN32 AND NOT LIBCLANG_BUILD_STATIC)) | |||
| if((NOT (WIN32 OR CYGWIN) AND LLVM_ENABLE_PIC) OR | |||
| ((WIN32 OR CYGWIN) AND NOT LIBCLANG_BUILD_STATIC)) | |||
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This bit here is quite unintuitive to read, but I don't have any specific preference for any better way of doing it either...
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Indeed, that's unfortunate and has always been a problem.
LLVM_ENABLE_PIC defaults to ON on Windows, so that condition never worked unless you explicitly disabled LLVM_ENABLE_PIC as found out by @jeremyd2019.
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this stops libclang.dll from building on (non-mingw) windows when we specify LLVM_ENABLE_PIC, can we revert that part of this change?
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Right, so in order not to change the behaviour for other windows platforms, this should probably be if ((NOT CYGWIN AND LLVM_ENABLE_PIC) OR ((WIN32 OR CYGWIN) AND NOT LIBCLANG_BUILD_STATIC)), i.e. removing the WIN32 OR part from the first part of the conditional?
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I'm confused now, the condition before had WIN32 AND NOT LIBCLANG_BUILD_STATIC but that branch was never hit because LLVM_ENABLE_PIC was defaulted ON on Windows. What exactly is LIBCLANG_BUILD_STATIC supposed to do, if not switch from building a shared libclang to building a static one?
Oh, the docs on the option does say "in addition to a shared one"
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As I recall, the libclang.dll did build successfully so I think that could be reverted. Perhaps I/we just misunderstood what that option was supposed to do
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as in,
if(LLVM_ENABLE_PIC OR ((WIN32 OR CYGWIN) AND NOT LIBCLANG_BUILD_STATIC))
Although I'm still not clear on what the WIN32 AND NOT LIBCLANG_BUILD_STATIC case is supposed to be doing, it's pretty clear that Cygwin is like WIN32 in regards to its shared/static libraries
This change follows MinGW decisions, otherwise build with GCC fail with: ``` FAILED: bin/msys-clang-cpp-21.0git.dll lib/libclang-cpp.dll.a ... /usr/lib/gcc/x86_64-pc-msys/13.3.0/../../../../x86_64-pc-msys/bin/ld: error: export ordinal too large: 92250 ``` Co-authored-by: jeremyd2019 <[email protected]>
This change follows MinGW decisions, otherwise build with GCC fail with: ``` FAILED: bin/msys-clang-cpp-21.0git.dll lib/libclang-cpp.dll.a ... /usr/lib/gcc/x86_64-pc-msys/13.3.0/../../../../x86_64-pc-msys/bin/ld: error: export ordinal too large: 92250 ``` Co-authored-by: jeremyd2019 <[email protected]>
This change follows MinGW decisions, otherwise build with GCC fail with: ``` FAILED: bin/msys-clang-cpp-21.0git.dll lib/libclang-cpp.dll.a ... /usr/lib/gcc/x86_64-pc-msys/13.3.0/../../../../x86_64-pc-msys/bin/ld: error: export ordinal too large: 92250 ``` Co-authored-by: jeremyd2019 <[email protected]>
This change follows MinGW decisions, otherwise build with GCC fail with: ``` FAILED: bin/msys-clang-cpp-21.0git.dll lib/libclang-cpp.dll.a ... /usr/lib/gcc/x86_64-pc-msys/13.3.0/../../../../x86_64-pc-msys/bin/ld: error: export ordinal too large: 92250 ``` Co-authored-by: jeremyd2019 <[email protected]>
This change follows MinGW decisions, otherwise build with GCC fail with: ``` FAILED: bin/msys-clang-cpp-21.0git.dll lib/libclang-cpp.dll.a ... /usr/lib/gcc/x86_64-pc-msys/13.3.0/../../../../x86_64-pc-msys/bin/ld: error: export ordinal too large: 92250 ``` Co-authored-by: jeremyd2019 <[email protected]>
This change follows MinGW decisions, otherwise build with GCC fail with: ``` FAILED: bin/msys-clang-cpp-21.0git.dll lib/libclang-cpp.dll.a ... /usr/lib/gcc/x86_64-pc-msys/13.3.0/../../../../x86_64-pc-msys/bin/ld: error: export ordinal too large: 92250 ``` Co-authored-by: jeremyd2019 <[email protected]>
This change follows MinGW decisions, otherwise build with GCC fail with:
Split out from #134494