[LLVM][Clang][Cygwin] Fix Cygwin builds #134458

mati865 · 2025-04-04T22:21:17Z

This is part of the fixes from https://github.com/mati865/llvm-project/commits/cygwin-more-fixes/ that I consider good enough to upstream.

The other branch with hacky changes even goes as far as making Clang successfully build LLVM+LLD+itself (although it still calls GCC for linking), but it would take a lot more work that I'm not planning to do.

llvmbot · 2025-04-04T22:21:49Z

@llvm/pr-subscribers-clang-driver
@llvm/pr-subscribers-backend-x86
@llvm/pr-subscribers-llvm-support

@llvm/pr-subscribers-clang

Author: Mateusz Mikuła (mati865)

Changes

This is part of the fixes from https://github.com/mati865/llvm-project/commits/cygwin-more-fixes/ that I consider good enough to upstream.

The other branch with hacky changes even goes as far as making Clang successfully build LLVM+LLD+itself (although it still calls GCC for linking), but it would take a lot more work that I'm not planning to do.

Full diff: https://github.com/llvm/llvm-project/pull/134458.diff

16 Files Affected:

(modified) clang/include/clang/Support/Compiler.h (+1-1)
(modified) clang/lib/AST/ItaniumCXXABI.cpp (+1-1)
(modified) clang/lib/AST/RecordLayoutBuilder.cpp (+1-1)
(modified) clang/lib/Basic/Targets/X86.h (-1)
(modified) clang/lib/CodeGen/CodeGenModule.cpp (+1-1)
(modified) clang/lib/CodeGen/ItaniumCXXABI.cpp (+2-2)
(modified) clang/lib/CodeGen/Targets/X86.cpp (+1-1)
(modified) clang/lib/Driver/ToolChain.cpp (+1-1)
(modified) clang/lib/Sema/SemaDecl.cpp (+1-1)
(modified) clang/lib/Sema/SemaDeclCXX.cpp (+2-2)
(modified) clang/lib/Sema/SemaTemplate.cpp (+4-4)
(modified) clang/tools/libclang/CIndexer.cpp (-1)
(modified) llvm/cmake/modules/AddLLVM.cmake (+1-1)
(modified) llvm/include/llvm/Support/Compiler.h (+2-2)
(modified) llvm/lib/Target/CMakeLists.txt (+1-1)
(modified) llvm/tools/llvm-shlib/CMakeLists.txt (+2-2)

diff --git a/clang/include/clang/Support/Compiler.h b/clang/include/clang/Support/Compiler.h
index 5a74f8e3b6723..e1ae3eda4ccc2 100644
--- a/clang/include/clang/Support/Compiler.h
+++ b/clang/include/clang/Support/Compiler.h
@@ -50,7 +50,7 @@
 #define CLANG_EXPORT_TEMPLATE
 #endif
 #elif defined(__ELF__) || defined(__MINGW32__) || defined(_AIX) ||             \
-    defined(__MVS__)
+    defined(__MVS__) || defined(__CYGWIN__)
 #define CLANG_ABI LLVM_ATTRIBUTE_VISIBILITY_DEFAULT
 #define CLANG_TEMPLATE_ABI LLVM_ATTRIBUTE_VISIBILITY_DEFAULT
 #define CLANG_EXPORT_TEMPLATE
diff --git a/clang/lib/AST/ItaniumCXXABI.cpp b/clang/lib/AST/ItaniumCXXABI.cpp
index a1b2551419f5e..d866f6023e146 100644
--- a/clang/lib/AST/ItaniumCXXABI.cpp
+++ b/clang/lib/AST/ItaniumCXXABI.cpp
@@ -236,7 +236,7 @@ class ItaniumCXXABI : public CXXABI {
 
   CallingConv getDefaultMethodCallConv(bool isVariadic) const override {
     const llvm::Triple &T = Context.getTargetInfo().getTriple();
-    if (!isVariadic && T.isWindowsGNUEnvironment() &&
+    if (!isVariadic && T.isOSCygMing() &&
         T.getArch() == llvm::Triple::x86)
       return CC_X86ThisCall;
     return Context.getTargetInfo().getDefaultCallingConv();
diff --git a/clang/lib/AST/RecordLayoutBuilder.cpp b/clang/lib/AST/RecordLayoutBuilder.cpp
index 3e756ab9b9bfe..43b54850598af 100644
--- a/clang/lib/AST/RecordLayoutBuilder.cpp
+++ b/clang/lib/AST/RecordLayoutBuilder.cpp
@@ -1950,7 +1950,7 @@ void ItaniumRecordLayoutBuilder::LayoutField(const FieldDecl *D,
           // silently there. For other targets that have ms_struct enabled
           // (most probably via a pragma or attribute), trigger a diagnostic
           // that defaults to an error.
-          if (!Context.getTargetInfo().getTriple().isWindowsGNUEnvironment())
+          if (!Context.getTargetInfo().getTriple().isOSCygMing())
             Diag(D->getLocation(), diag::warn_npot_ms_struct);
         }
         if (TypeSize > FieldAlign &&
diff --git a/clang/lib/Basic/Targets/X86.h b/clang/lib/Basic/Targets/X86.h
index 205edcab9ccb3..7ca2952f73451 100644
--- a/clang/lib/Basic/Targets/X86.h
+++ b/clang/lib/Basic/Targets/X86.h
@@ -948,7 +948,6 @@ class LLVM_LIBRARY_VISIBILITY CygwinX86_64TargetInfo : public X86_64TargetInfo {
   CygwinX86_64TargetInfo(const llvm::Triple &Triple, const TargetOptions &Opts)
       : X86_64TargetInfo(Triple, Opts) {
     this->WCharType = TargetInfo::UnsignedShort;
-    TLSSupported = false;
   }
 
   void getTargetDefines(const LangOptions &Opts,
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 8f9cf965af2b9..f4cf4f8ae7c0d 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -1680,7 +1680,7 @@ static bool shouldAssumeDSOLocal(const CodeGenModule &CGM,
 
   const llvm::Triple &TT = CGM.getTriple();
   const auto &CGOpts = CGM.getCodeGenOpts();
-  if (TT.isWindowsGNUEnvironment()) {
+  if (TT.isOSCygMing()) {
     // In MinGW, variables without DLLImport can still be automatically
     // imported from a DLL by the linker; don't mark variables that
     // potentially could come from another DLL as DSO local.
diff --git a/clang/lib/CodeGen/ItaniumCXXABI.cpp b/clang/lib/CodeGen/ItaniumCXXABI.cpp
index 2822d526a54b0..f8c63d185a24a 100644
--- a/clang/lib/CodeGen/ItaniumCXXABI.cpp
+++ b/clang/lib/CodeGen/ItaniumCXXABI.cpp
@@ -3757,7 +3757,7 @@ static bool ShouldUseExternalRTTIDescriptor(CodeGenModule &CGM,
     bool IsDLLImport = RD->hasAttr<DLLImportAttr>();
 
     // Don't import the RTTI but emit it locally.
-    if (CGM.getTriple().isWindowsGNUEnvironment())
+    if (CGM.getTriple().isOSCygMing())
       return false;
 
     if (CGM.getVTables().isVTableExternal(RD)) {
@@ -4047,7 +4047,7 @@ static llvm::GlobalVariable::LinkageTypes getTypeInfoLinkage(CodeGenModule &CGM,
           !CGM.getContext()
                .getTargetInfo()
                .getTriple()
-               .isWindowsGNUEnvironment())
+               .isOSCygMing())
         return CGM.getVTableLinkage(RD);
     }
 
diff --git a/clang/lib/CodeGen/Targets/X86.cpp b/clang/lib/CodeGen/Targets/X86.cpp
index b36a6e1396653..cb09c52856744 100644
--- a/clang/lib/CodeGen/Targets/X86.cpp
+++ b/clang/lib/CodeGen/Targets/X86.cpp
@@ -1391,7 +1391,7 @@ class WinX86_64ABIInfo : public ABIInfo {
 public:
   WinX86_64ABIInfo(CodeGen::CodeGenTypes &CGT, X86AVXABILevel AVXLevel)
       : ABIInfo(CGT), AVXLevel(AVXLevel),
-        IsMingw64(getTarget().getTriple().isWindowsGNUEnvironment()) {}
+        IsMingw64(getTarget().getTriple().isOSCygMing()) {}
 
   void computeInfo(CGFunctionInfo &FI) const override;
 
diff --git a/clang/lib/Driver/ToolChain.cpp b/clang/lib/Driver/ToolChain.cpp
index 36d0ae34dec86..26d7311227327 100644
--- a/clang/lib/Driver/ToolChain.cpp
+++ b/clang/lib/Driver/ToolChain.cpp
@@ -745,7 +745,7 @@ std::string ToolChain::buildCompilerRTBasename(const llvm::opt::ArgList &Args,
     break;
   case ToolChain::FT_Shared:
     Suffix = TT.isOSWindows()
-                 ? (TT.isWindowsGNUEnvironment() ? ".dll.a" : ".lib")
+                 ? (TT.isOSCygMing() ? ".dll.a" : ".lib")
                  : ".so";
     break;
   }
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index d630f9bd409fd..351d3a4ee74d9 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -12536,7 +12536,7 @@ static bool isDefaultStdCall(FunctionDecl *FD, Sema &S) {
 
   // Default calling convention for MinGW is __cdecl
   const llvm::Triple &T = S.Context.getTargetInfo().getTriple();
-  if (T.isWindowsGNUEnvironment())
+  if (T.isOSCygMing())
     return false;
 
   // Default calling convention for WinMain, wWinMain and DllMain
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index 07379c6876731..e201e1e7ae0ed 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -6272,7 +6272,7 @@ static void ReferenceDllExportedMembers(Sema &S, CXXRecordDecl *Class) {
     }
   } MarkingDllexportedContext(S, Class, ClassAttr->getLocation());
 
-  if (S.Context.getTargetInfo().getTriple().isWindowsGNUEnvironment())
+  if (S.Context.getTargetInfo().getTriple().isOSCygMing())
     S.MarkVTableUsed(Class->getLocation(), Class, true);
 
   for (Decl *Member : Class->decls()) {
@@ -6574,7 +6574,7 @@ void Sema::checkClassLevelDLLAttribute(CXXRecordDecl *Class) {
   // declarations, except in MinGW mode.
   if (ClassExported && !ClassAttr->isInherited() &&
       TSK == TSK_ExplicitInstantiationDeclaration &&
-      !Context.getTargetInfo().getTriple().isWindowsGNUEnvironment()) {
+      !Context.getTargetInfo().getTriple().isOSCygMing()) {
     Class->dropAttr<DLLExportAttr>();
     return;
   }
diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp
index 153f44f8ec67a..32a3eea78c4da 100644
--- a/clang/lib/Sema/SemaTemplate.cpp
+++ b/clang/lib/Sema/SemaTemplate.cpp
@@ -8890,7 +8890,7 @@ Sema::CheckSpecializationInstantiationRedecl(SourceLocation NewLoc,
         // still okay to specialize it.
         StripImplicitInstantiation(
             PrevDecl,
-            Context.getTargetInfo().getTriple().isWindowsGNUEnvironment());
+            Context.getTargetInfo().getTriple().isOSCygMing());
         return false;
       }
       // Fall through
@@ -9758,7 +9758,7 @@ DeclResult Sema::ActOnExplicitInstantiation(
                                        : TSK_ExplicitInstantiationDeclaration;
 
   if (TSK == TSK_ExplicitInstantiationDeclaration &&
-      !Context.getTargetInfo().getTriple().isWindowsGNUEnvironment()) {
+      !Context.getTargetInfo().getTriple().isOSCygMing()) {
     // Check for dllexport class template instantiation declarations,
     // except for MinGW mode.
     for (const ParsedAttr &AL : Attr) {
@@ -9823,7 +9823,7 @@ DeclResult Sema::ActOnExplicitInstantiation(
     = PrevDecl ? PrevDecl->getTemplateSpecializationKind() : TSK_Undeclared;
 
   if (TSK == TSK_ExplicitInstantiationDefinition && PrevDecl != nullptr &&
-      Context.getTargetInfo().getTriple().isWindowsGNUEnvironment()) {
+      Context.getTargetInfo().getTriple().isOSCygMing()) {
     // Check for dllexport class template instantiation definitions in MinGW
     // mode, if a previous declaration of the instantiation was seen.
     for (const ParsedAttr &AL : Attr) {
@@ -9991,7 +9991,7 @@ DeclResult Sema::ActOnExplicitInstantiation(
     // In MinGW mode, export the template instantiation if the declaration
     // was marked dllexport.
     if (PrevDecl_TSK == TSK_ExplicitInstantiationDeclaration &&
-        Context.getTargetInfo().getTriple().isWindowsGNUEnvironment() &&
+        Context.getTargetInfo().getTriple().isOSCygMing() &&
         PrevDecl->hasAttr<DLLExportAttr>()) {
       dllExportImportClassTemplateSpecialization(*this, Def);
     }
diff --git a/clang/tools/libclang/CIndexer.cpp b/clang/tools/libclang/CIndexer.cpp
index 12d9d418dea51..1b9d58bc439ad 100644
--- a/clang/tools/libclang/CIndexer.cpp
+++ b/clang/tools/libclang/CIndexer.cpp
@@ -29,7 +29,6 @@
 #ifdef __CYGWIN__
 #include <cygwin/version.h>
 #include <sys/cygwin.h>
-#define _WIN32 1
 #endif
 
 #ifdef _WIN32
diff --git a/llvm/cmake/modules/AddLLVM.cmake b/llvm/cmake/modules/AddLLVM.cmake
index 39f0e28a249d3..66462dc328dd0 100644
--- a/llvm/cmake/modules/AddLLVM.cmake
+++ b/llvm/cmake/modules/AddLLVM.cmake
@@ -666,7 +666,7 @@ function(llvm_add_library name)
     # When building shared objects for each target there are some internal APIs
     # that are used across shared objects which we can't hide.
     if (LLVM_BUILD_LLVM_DYLIB_VIS AND NOT BUILD_SHARED_LIBS AND NOT APPLE AND
-        (NOT (WIN32 OR CYGWIN) OR (MINGW AND CMAKE_CXX_COMPILER_ID MATCHES "Clang")) AND
+        (NOT (WIN32 OR CYGWIN) OR ((MINGW OR CYGWIN) AND CMAKE_CXX_COMPILER_ID MATCHES "Clang")) AND
         NOT (${CMAKE_SYSTEM_NAME} MATCHES "AIX") AND
         NOT DEFINED CMAKE_CXX_VISIBILITY_PRESET)
 
diff --git a/llvm/include/llvm/Support/Compiler.h b/llvm/include/llvm/Support/Compiler.h
index d3772896069cc..5499f91137339 100644
--- a/llvm/include/llvm/Support/Compiler.h
+++ b/llvm/include/llvm/Support/Compiler.h
@@ -129,7 +129,7 @@
 #endif
 
 #if (!(defined(_WIN32) || defined(__CYGWIN__)) ||                              \
-     (defined(__MINGW32__) && defined(__clang__)))
+    ((defined(__MINGW32__) || defined (__CYGWIN__)) && defined(__clang__)))
 #define LLVM_LIBRARY_VISIBILITY LLVM_ATTRIBUTE_VISIBILITY_HIDDEN
 // Clang compilers older then 15 do not support gnu style attributes on
 // namespaces.
@@ -198,7 +198,7 @@
 #endif
 #define LLVM_ABI_EXPORT __declspec(dllexport)
 #elif defined(__ELF__) || defined(__MINGW32__) || defined(_AIX) ||             \
-    defined(__MVS__)
+    defined(__MVS__) || defined(__CYGWIN__)
 #define LLVM_ABI LLVM_ATTRIBUTE_VISIBILITY_DEFAULT
 #define LLVM_TEMPLATE_ABI LLVM_ATTRIBUTE_VISIBILITY_DEFAULT
 #define LLVM_EXPORT_TEMPLATE
diff --git a/llvm/lib/Target/CMakeLists.txt b/llvm/lib/Target/CMakeLists.txt
index 9472288229cac..f5f6f5386f899 100644
--- a/llvm/lib/Target/CMakeLists.txt
+++ b/llvm/lib/Target/CMakeLists.txt
@@ -22,7 +22,7 @@ add_llvm_component_library(LLVMTarget
 # When building shared objects for each target there are some internal APIs
 # that are used across shared objects which we can't hide.
 if (NOT BUILD_SHARED_LIBS AND NOT APPLE AND
-    (NOT (WIN32 OR CYGWIN) OR (MINGW AND CMAKE_CXX_COMPILER_ID MATCHES "Clang")) AND
+    (NOT (WIN32 OR CYGWIN) OR ((MINGW OR CYGWIN) AND CMAKE_CXX_COMPILER_ID MATCHES "Clang")) AND
     NOT (${CMAKE_SYSTEM_NAME} MATCHES "AIX") AND
     NOT DEFINED CMAKE_CXX_VISIBILITY_PRESET)
   # Set default visibility to hidden, so we don't export all the Target classes
diff --git a/llvm/tools/llvm-shlib/CMakeLists.txt b/llvm/tools/llvm-shlib/CMakeLists.txt
index a5b0cab0f1ce5..05551dc57402a 100644
--- a/llvm/tools/llvm-shlib/CMakeLists.txt
+++ b/llvm/tools/llvm-shlib/CMakeLists.txt
@@ -66,11 +66,11 @@ if(LLVM_BUILD_LLVM_DYLIB)
     else()
       # GNU ld doesn't resolve symbols in the version script.
       set(LIB_NAMES -Wl,--whole-archive ${LIB_NAMES} -Wl,--no-whole-archive)
-      if (NOT LLVM_LINKER_IS_SOLARISLD AND NOT MINGW)
+      if (NOT LLVM_LINKER_IS_SOLARISLD AND NOT (MINGW OR CYGWIN))
         # Solaris ld does not accept global: *; so there is no way to version *all* global symbols
         set(LIB_NAMES -Wl,--version-script,${LLVM_LIBRARY_DIR}/tools/llvm-shlib/simple_version_script.map ${LIB_NAMES})
       endif()
-      if (NOT MINGW AND NOT LLVM_LINKER_IS_SOLARISLD_ILLUMOS)
+      if (NOT (MINGW OR CYGWIN) AND NOT LLVM_LINKER_IS_SOLARISLD_ILLUMOS)
         # Optimize function calls for default visibility definitions to avoid PLT and
         # reduce dynamic relocations.
         # Note: for -fno-pic default, the address of a function may be different from

llvmbot · 2025-04-04T22:21:50Z

@llvm/pr-subscribers-clang-codegen

Author: Mateusz Mikuła (mati865)

Changes

This is part of the fixes from https://github.com/mati865/llvm-project/commits/cygwin-more-fixes/ that I consider good enough to upstream.

The other branch with hacky changes even goes as far as making Clang successfully build LLVM+LLD+itself (although it still calls GCC for linking), but it would take a lot more work that I'm not planning to do.

Full diff: https://github.com/llvm/llvm-project/pull/134458.diff

16 Files Affected:

(modified) clang/include/clang/Support/Compiler.h (+1-1)
(modified) clang/lib/AST/ItaniumCXXABI.cpp (+1-1)
(modified) clang/lib/AST/RecordLayoutBuilder.cpp (+1-1)
(modified) clang/lib/Basic/Targets/X86.h (-1)
(modified) clang/lib/CodeGen/CodeGenModule.cpp (+1-1)
(modified) clang/lib/CodeGen/ItaniumCXXABI.cpp (+2-2)
(modified) clang/lib/CodeGen/Targets/X86.cpp (+1-1)
(modified) clang/lib/Driver/ToolChain.cpp (+1-1)
(modified) clang/lib/Sema/SemaDecl.cpp (+1-1)
(modified) clang/lib/Sema/SemaDeclCXX.cpp (+2-2)
(modified) clang/lib/Sema/SemaTemplate.cpp (+4-4)
(modified) clang/tools/libclang/CIndexer.cpp (-1)
(modified) llvm/cmake/modules/AddLLVM.cmake (+1-1)
(modified) llvm/include/llvm/Support/Compiler.h (+2-2)
(modified) llvm/lib/Target/CMakeLists.txt (+1-1)
(modified) llvm/tools/llvm-shlib/CMakeLists.txt (+2-2)

diff --git a/clang/include/clang/Support/Compiler.h b/clang/include/clang/Support/Compiler.h
index 5a74f8e3b6723..e1ae3eda4ccc2 100644
--- a/clang/include/clang/Support/Compiler.h
+++ b/clang/include/clang/Support/Compiler.h
@@ -50,7 +50,7 @@
 #define CLANG_EXPORT_TEMPLATE
 #endif
 #elif defined(__ELF__) || defined(__MINGW32__) || defined(_AIX) ||             \
-    defined(__MVS__)
+    defined(__MVS__) || defined(__CYGWIN__)
 #define CLANG_ABI LLVM_ATTRIBUTE_VISIBILITY_DEFAULT
 #define CLANG_TEMPLATE_ABI LLVM_ATTRIBUTE_VISIBILITY_DEFAULT
 #define CLANG_EXPORT_TEMPLATE
diff --git a/clang/lib/AST/ItaniumCXXABI.cpp b/clang/lib/AST/ItaniumCXXABI.cpp
index a1b2551419f5e..d866f6023e146 100644
--- a/clang/lib/AST/ItaniumCXXABI.cpp
+++ b/clang/lib/AST/ItaniumCXXABI.cpp
@@ -236,7 +236,7 @@ class ItaniumCXXABI : public CXXABI {
 
   CallingConv getDefaultMethodCallConv(bool isVariadic) const override {
     const llvm::Triple &T = Context.getTargetInfo().getTriple();
-    if (!isVariadic && T.isWindowsGNUEnvironment() &&
+    if (!isVariadic && T.isOSCygMing() &&
         T.getArch() == llvm::Triple::x86)
       return CC_X86ThisCall;
     return Context.getTargetInfo().getDefaultCallingConv();
diff --git a/clang/lib/AST/RecordLayoutBuilder.cpp b/clang/lib/AST/RecordLayoutBuilder.cpp
index 3e756ab9b9bfe..43b54850598af 100644
--- a/clang/lib/AST/RecordLayoutBuilder.cpp
+++ b/clang/lib/AST/RecordLayoutBuilder.cpp
@@ -1950,7 +1950,7 @@ void ItaniumRecordLayoutBuilder::LayoutField(const FieldDecl *D,
           // silently there. For other targets that have ms_struct enabled
           // (most probably via a pragma or attribute), trigger a diagnostic
           // that defaults to an error.
-          if (!Context.getTargetInfo().getTriple().isWindowsGNUEnvironment())
+          if (!Context.getTargetInfo().getTriple().isOSCygMing())
             Diag(D->getLocation(), diag::warn_npot_ms_struct);
         }
         if (TypeSize > FieldAlign &&
diff --git a/clang/lib/Basic/Targets/X86.h b/clang/lib/Basic/Targets/X86.h
index 205edcab9ccb3..7ca2952f73451 100644
--- a/clang/lib/Basic/Targets/X86.h
+++ b/clang/lib/Basic/Targets/X86.h
@@ -948,7 +948,6 @@ class LLVM_LIBRARY_VISIBILITY CygwinX86_64TargetInfo : public X86_64TargetInfo {
   CygwinX86_64TargetInfo(const llvm::Triple &Triple, const TargetOptions &Opts)
       : X86_64TargetInfo(Triple, Opts) {
     this->WCharType = TargetInfo::UnsignedShort;
-    TLSSupported = false;
   }
 
   void getTargetDefines(const LangOptions &Opts,
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 8f9cf965af2b9..f4cf4f8ae7c0d 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -1680,7 +1680,7 @@ static bool shouldAssumeDSOLocal(const CodeGenModule &CGM,
 
   const llvm::Triple &TT = CGM.getTriple();
   const auto &CGOpts = CGM.getCodeGenOpts();
-  if (TT.isWindowsGNUEnvironment()) {
+  if (TT.isOSCygMing()) {
     // In MinGW, variables without DLLImport can still be automatically
     // imported from a DLL by the linker; don't mark variables that
     // potentially could come from another DLL as DSO local.
diff --git a/clang/lib/CodeGen/ItaniumCXXABI.cpp b/clang/lib/CodeGen/ItaniumCXXABI.cpp
index 2822d526a54b0..f8c63d185a24a 100644
--- a/clang/lib/CodeGen/ItaniumCXXABI.cpp
+++ b/clang/lib/CodeGen/ItaniumCXXABI.cpp
@@ -3757,7 +3757,7 @@ static bool ShouldUseExternalRTTIDescriptor(CodeGenModule &CGM,
     bool IsDLLImport = RD->hasAttr<DLLImportAttr>();
 
     // Don't import the RTTI but emit it locally.
-    if (CGM.getTriple().isWindowsGNUEnvironment())
+    if (CGM.getTriple().isOSCygMing())
       return false;
 
     if (CGM.getVTables().isVTableExternal(RD)) {
@@ -4047,7 +4047,7 @@ static llvm::GlobalVariable::LinkageTypes getTypeInfoLinkage(CodeGenModule &CGM,
           !CGM.getContext()
                .getTargetInfo()
                .getTriple()
-               .isWindowsGNUEnvironment())
+               .isOSCygMing())
         return CGM.getVTableLinkage(RD);
     }
 
diff --git a/clang/lib/CodeGen/Targets/X86.cpp b/clang/lib/CodeGen/Targets/X86.cpp
index b36a6e1396653..cb09c52856744 100644
--- a/clang/lib/CodeGen/Targets/X86.cpp
+++ b/clang/lib/CodeGen/Targets/X86.cpp
@@ -1391,7 +1391,7 @@ class WinX86_64ABIInfo : public ABIInfo {
 public:
   WinX86_64ABIInfo(CodeGen::CodeGenTypes &CGT, X86AVXABILevel AVXLevel)
       : ABIInfo(CGT), AVXLevel(AVXLevel),
-        IsMingw64(getTarget().getTriple().isWindowsGNUEnvironment()) {}
+        IsMingw64(getTarget().getTriple().isOSCygMing()) {}
 
   void computeInfo(CGFunctionInfo &FI) const override;
 
diff --git a/clang/lib/Driver/ToolChain.cpp b/clang/lib/Driver/ToolChain.cpp
index 36d0ae34dec86..26d7311227327 100644
--- a/clang/lib/Driver/ToolChain.cpp
+++ b/clang/lib/Driver/ToolChain.cpp
@@ -745,7 +745,7 @@ std::string ToolChain::buildCompilerRTBasename(const llvm::opt::ArgList &Args,
     break;
   case ToolChain::FT_Shared:
     Suffix = TT.isOSWindows()
-                 ? (TT.isWindowsGNUEnvironment() ? ".dll.a" : ".lib")
+                 ? (TT.isOSCygMing() ? ".dll.a" : ".lib")
                  : ".so";
     break;
   }
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index d630f9bd409fd..351d3a4ee74d9 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -12536,7 +12536,7 @@ static bool isDefaultStdCall(FunctionDecl *FD, Sema &S) {
 
   // Default calling convention for MinGW is __cdecl
   const llvm::Triple &T = S.Context.getTargetInfo().getTriple();
-  if (T.isWindowsGNUEnvironment())
+  if (T.isOSCygMing())
     return false;
 
   // Default calling convention for WinMain, wWinMain and DllMain
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index 07379c6876731..e201e1e7ae0ed 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -6272,7 +6272,7 @@ static void ReferenceDllExportedMembers(Sema &S, CXXRecordDecl *Class) {
     }
   } MarkingDllexportedContext(S, Class, ClassAttr->getLocation());
 
-  if (S.Context.getTargetInfo().getTriple().isWindowsGNUEnvironment())
+  if (S.Context.getTargetInfo().getTriple().isOSCygMing())
     S.MarkVTableUsed(Class->getLocation(), Class, true);
 
   for (Decl *Member : Class->decls()) {
@@ -6574,7 +6574,7 @@ void Sema::checkClassLevelDLLAttribute(CXXRecordDecl *Class) {
   // declarations, except in MinGW mode.
   if (ClassExported && !ClassAttr->isInherited() &&
       TSK == TSK_ExplicitInstantiationDeclaration &&
-      !Context.getTargetInfo().getTriple().isWindowsGNUEnvironment()) {
+      !Context.getTargetInfo().getTriple().isOSCygMing()) {
     Class->dropAttr<DLLExportAttr>();
     return;
   }
diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp
index 153f44f8ec67a..32a3eea78c4da 100644
--- a/clang/lib/Sema/SemaTemplate.cpp
+++ b/clang/lib/Sema/SemaTemplate.cpp
@@ -8890,7 +8890,7 @@ Sema::CheckSpecializationInstantiationRedecl(SourceLocation NewLoc,
         // still okay to specialize it.
         StripImplicitInstantiation(
             PrevDecl,
-            Context.getTargetInfo().getTriple().isWindowsGNUEnvironment());
+            Context.getTargetInfo().getTriple().isOSCygMing());
         return false;
       }
       // Fall through
@@ -9758,7 +9758,7 @@ DeclResult Sema::ActOnExplicitInstantiation(
                                        : TSK_ExplicitInstantiationDeclaration;
 
   if (TSK == TSK_ExplicitInstantiationDeclaration &&
-      !Context.getTargetInfo().getTriple().isWindowsGNUEnvironment()) {
+      !Context.getTargetInfo().getTriple().isOSCygMing()) {
     // Check for dllexport class template instantiation declarations,
     // except for MinGW mode.
     for (const ParsedAttr &AL : Attr) {
@@ -9823,7 +9823,7 @@ DeclResult Sema::ActOnExplicitInstantiation(
     = PrevDecl ? PrevDecl->getTemplateSpecializationKind() : TSK_Undeclared;
 
   if (TSK == TSK_ExplicitInstantiationDefinition && PrevDecl != nullptr &&
-      Context.getTargetInfo().getTriple().isWindowsGNUEnvironment()) {
+      Context.getTargetInfo().getTriple().isOSCygMing()) {
     // Check for dllexport class template instantiation definitions in MinGW
     // mode, if a previous declaration of the instantiation was seen.
     for (const ParsedAttr &AL : Attr) {
@@ -9991,7 +9991,7 @@ DeclResult Sema::ActOnExplicitInstantiation(
     // In MinGW mode, export the template instantiation if the declaration
     // was marked dllexport.
     if (PrevDecl_TSK == TSK_ExplicitInstantiationDeclaration &&
-        Context.getTargetInfo().getTriple().isWindowsGNUEnvironment() &&
+        Context.getTargetInfo().getTriple().isOSCygMing() &&
         PrevDecl->hasAttr<DLLExportAttr>()) {
       dllExportImportClassTemplateSpecialization(*this, Def);
     }
diff --git a/clang/tools/libclang/CIndexer.cpp b/clang/tools/libclang/CIndexer.cpp
index 12d9d418dea51..1b9d58bc439ad 100644
--- a/clang/tools/libclang/CIndexer.cpp
+++ b/clang/tools/libclang/CIndexer.cpp
@@ -29,7 +29,6 @@
 #ifdef __CYGWIN__
 #include <cygwin/version.h>
 #include <sys/cygwin.h>
-#define _WIN32 1
 #endif
 
 #ifdef _WIN32
diff --git a/llvm/cmake/modules/AddLLVM.cmake b/llvm/cmake/modules/AddLLVM.cmake
index 39f0e28a249d3..66462dc328dd0 100644
--- a/llvm/cmake/modules/AddLLVM.cmake
+++ b/llvm/cmake/modules/AddLLVM.cmake
@@ -666,7 +666,7 @@ function(llvm_add_library name)
     # When building shared objects for each target there are some internal APIs
     # that are used across shared objects which we can't hide.
     if (LLVM_BUILD_LLVM_DYLIB_VIS AND NOT BUILD_SHARED_LIBS AND NOT APPLE AND
-        (NOT (WIN32 OR CYGWIN) OR (MINGW AND CMAKE_CXX_COMPILER_ID MATCHES "Clang")) AND
+        (NOT (WIN32 OR CYGWIN) OR ((MINGW OR CYGWIN) AND CMAKE_CXX_COMPILER_ID MATCHES "Clang")) AND
         NOT (${CMAKE_SYSTEM_NAME} MATCHES "AIX") AND
         NOT DEFINED CMAKE_CXX_VISIBILITY_PRESET)
 
diff --git a/llvm/include/llvm/Support/Compiler.h b/llvm/include/llvm/Support/Compiler.h
index d3772896069cc..5499f91137339 100644
--- a/llvm/include/llvm/Support/Compiler.h
+++ b/llvm/include/llvm/Support/Compiler.h
@@ -129,7 +129,7 @@
 #endif
 
 #if (!(defined(_WIN32) || defined(__CYGWIN__)) ||                              \
-     (defined(__MINGW32__) && defined(__clang__)))
+    ((defined(__MINGW32__) || defined (__CYGWIN__)) && defined(__clang__)))
 #define LLVM_LIBRARY_VISIBILITY LLVM_ATTRIBUTE_VISIBILITY_HIDDEN
 // Clang compilers older then 15 do not support gnu style attributes on
 // namespaces.
@@ -198,7 +198,7 @@
 #endif
 #define LLVM_ABI_EXPORT __declspec(dllexport)
 #elif defined(__ELF__) || defined(__MINGW32__) || defined(_AIX) ||             \
-    defined(__MVS__)
+    defined(__MVS__) || defined(__CYGWIN__)
 #define LLVM_ABI LLVM_ATTRIBUTE_VISIBILITY_DEFAULT
 #define LLVM_TEMPLATE_ABI LLVM_ATTRIBUTE_VISIBILITY_DEFAULT
 #define LLVM_EXPORT_TEMPLATE
diff --git a/llvm/lib/Target/CMakeLists.txt b/llvm/lib/Target/CMakeLists.txt
index 9472288229cac..f5f6f5386f899 100644
--- a/llvm/lib/Target/CMakeLists.txt
+++ b/llvm/lib/Target/CMakeLists.txt
@@ -22,7 +22,7 @@ add_llvm_component_library(LLVMTarget
 # When building shared objects for each target there are some internal APIs
 # that are used across shared objects which we can't hide.
 if (NOT BUILD_SHARED_LIBS AND NOT APPLE AND
-    (NOT (WIN32 OR CYGWIN) OR (MINGW AND CMAKE_CXX_COMPILER_ID MATCHES "Clang")) AND
+    (NOT (WIN32 OR CYGWIN) OR ((MINGW OR CYGWIN) AND CMAKE_CXX_COMPILER_ID MATCHES "Clang")) AND
     NOT (${CMAKE_SYSTEM_NAME} MATCHES "AIX") AND
     NOT DEFINED CMAKE_CXX_VISIBILITY_PRESET)
   # Set default visibility to hidden, so we don't export all the Target classes
diff --git a/llvm/tools/llvm-shlib/CMakeLists.txt b/llvm/tools/llvm-shlib/CMakeLists.txt
index a5b0cab0f1ce5..05551dc57402a 100644
--- a/llvm/tools/llvm-shlib/CMakeLists.txt
+++ b/llvm/tools/llvm-shlib/CMakeLists.txt
@@ -66,11 +66,11 @@ if(LLVM_BUILD_LLVM_DYLIB)
     else()
       # GNU ld doesn't resolve symbols in the version script.
       set(LIB_NAMES -Wl,--whole-archive ${LIB_NAMES} -Wl,--no-whole-archive)
-      if (NOT LLVM_LINKER_IS_SOLARISLD AND NOT MINGW)
+      if (NOT LLVM_LINKER_IS_SOLARISLD AND NOT (MINGW OR CYGWIN))
         # Solaris ld does not accept global: *; so there is no way to version *all* global symbols
         set(LIB_NAMES -Wl,--version-script,${LLVM_LIBRARY_DIR}/tools/llvm-shlib/simple_version_script.map ${LIB_NAMES})
       endif()
-      if (NOT MINGW AND NOT LLVM_LINKER_IS_SOLARISLD_ILLUMOS)
+      if (NOT (MINGW OR CYGWIN) AND NOT LLVM_LINKER_IS_SOLARISLD_ILLUMOS)
         # Optimize function calls for default visibility definitions to avoid PLT and
         # reduce dynamic relocations.
         # Note: for -fno-pic default, the address of a function may be different from

github-actions · 2025-04-04T22:23:42Z

✅ With the latest revision this PR passed the C/C++ code formatter.

efriedma-quic

Please split this into multiple pull requests; some of these probably need different reviewers, and GitHub doesn't provide any interface for reviewing multiple commits on separately.

We want regression tests for the changes for cygwin targets. (We should already have mingw regression tests for most of this stuff; you should be able to just add a RUN line with a cygwin triple.)

Suggested split for PRs:

Changes required to build LLVM/clang on a cygwin host using gcc.
Clang driver changes.
The TLSSupported change.
The C++ ABI changes.

mati865 · 2025-04-04T23:06:53Z

Sure, I'll split this in the upcoming days.

jeremyd2019 · 2025-04-06T16:48:56Z

clang/lib/AST/ItaniumCXXABI.cpp

@@ -236,8 +236,7 @@ class ItaniumCXXABI : public CXXABI {

  CallingConv getDefaultMethodCallConv(bool isVariadic) const override {
    const llvm::Triple &T = Context.getTargetInfo().getTriple();
-    if (!isVariadic && T.isWindowsGNUEnvironment() &&
-        T.getArch() == llvm::Triple::x86)
+    if (!isVariadic && T.isOSCygMing() && T.getArch() == llvm::Triple::x86)


I know this PR is closed, but for the record: this particular change appears to be wrong: on i686 cygwin with this change calls to libstdc++ basic_string::_M_assign crashed, but with this change backed out it's much happier.

mati865 added 4 commits April 5, 2025 00:29

[Clang][Cygwin] Enable few conditions that are shared with MinGW

adbcc7f

[Clang][Cygwin] Enable TLS

2b4dca0

[Clang][Cygwin] Fix symbol visibility definition

f5f299b

[LLVM][Cygwin] Fix symbol visibility definition

b44a1f8

mati865 force-pushed the cygwin-fixes branch from 31b30d0 to c2a1e85 Compare April 4, 2025 22:29

efriedma-quic reviewed Apr 4, 2025

View reviewed changes

mati865 force-pushed the cygwin-fixes branch from c2a1e85 to b44a1f8 Compare April 4, 2025 23:04

mati865 marked this pull request as draft April 4, 2025 23:07

mati865 closed this Apr 4, 2025

This was referenced Apr 4, 2025

llvm: update to 20.1.2 msys2/MSYS2-packages#5308

Merged

[LLVM][Clang][Cygwin] Fix building Clang for Cygwin #134494

Closed

jeremyd2019 reviewed Apr 6, 2025

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mati865 deleted the cygwin-fixes branch May 19, 2025 16:32

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