remove Demangle dependency on Support

Author: andrurogerz

libcxxabi/src/demangle/DemangleConfig.h

@@ -107,4 +107,8 @@
 #define DEMANGLE_NAMESPACE_BEGIN namespace { namespace itanium_demangle {
 #define DEMANGLE_NAMESPACE_END } }
 
+// The DEMANGLE_ABI macro resolves to nothing when building libc++abi. Only
+// the llvm copy defines DEMANGLE_ABI as a visibility attribute.
+#define DEMANGLE_ABI
+
 #endif // LIBCXXABI_DEMANGLE_DEMANGLE_CONFIG_H

libcxxabi/src/demangle/ItaniumDemangle.h

@@ -19,7 +19,6 @@
 #include "DemangleConfig.h"
 #include "StringViewExtras.h"
 #include "Utility.h"
-#include "Visibility.h"
 #include <algorithm>
 #include <cctype>
 #include <cstdint>

libcxxabi/src/demangle/Visibility.h

@@ -1,8 +1,7 @@
 #!/bin/bash
 
-# Copies the 'demangle' library, excluding 'DemangleConfig.h' and
-# 'Visibility.h', to llvm. If no llvm directory is specified, then assume a
-# monorepo layout.
+# Copies the 'demangle' library, excluding 'DemangleConfig.h', to llvm. If no
+# llvm directory is specified, then assume a monorepo layout.
 
 set -e
 

libcxxabi/src/demangle/cp-to-llvm.sh

@@ -1078,10 +1078,9 @@ if (LLVM_BUILD_LLVM_DYLIB OR LLVM_BUILD_SHARED_LIBS OR LLVM_ENABLE_PLUGINS)
   set(LLVM_ENABLE_LLVM_EXPORT_ANNOTATIONS ON)
 endif()
 
-# Because LLVM-C and Demangle libraries are built into the LLVM library, for now
-# we export their symbols if LLVM symbols are exported.
+# Because LLVM-C is built into the LLVM library, for now export its symbols
+# whenever LLVM symbols are exported.
 set(LLVM_ENABLE_LLVM_C_EXPORT_ANNOTATIONS ${LLVM_ENABLE_LLVM_EXPORT_ANNOTATIONS})
-set(LLVM_ENABLE_DEMANGLE_EXPORT_ANNOTATIONS ${LLVM_ENABLE_LLVM_EXPORT_ANNOTATIONS})
 
 set(LLVM_ENABLE_NEW_PASS_MANAGER TRUE CACHE BOOL
   "Enable the new pass manager by default.")

llvm/CMakeLists.txt

@@ -9,7 +9,7 @@
 #ifndef LLVM_DEMANGLE_DEMANGLE_H
 #define LLVM_DEMANGLE_DEMANGLE_H
 
-#include "Visibility.h"
+#include "DemangleConfig.h"
 #include <cstddef>
 #include <optional>
 #include <string>

llvm/include/llvm/Demangle/Demangle.h

@@ -94,4 +94,24 @@
 #define DEMANGLE_NAMESPACE_BEGIN namespace llvm { namespace itanium_demangle {
 #define DEMANGLE_NAMESPACE_END } }
 
+/// DEMANGLE_ABI is the export/visibility macro used to mark symbols delcared in
+/// llvm/Demangle as exported when built as a shared library.
+#if defined(LLVM_BUILD_STATIC) || !defined(LLVM_ENABLE_LLVM_EXPORT_ANNOTATIONS)
+#define DEMANGLE_ABI
+#else
+#if defined(_WIN32)
+#if defined(LLVM_EXPORTS)
+#define DEMANGLE_ABI __declspec(dllexport)
+#else
+#define DEMANGLE_ABI__declspec(dllimport)
+#endif
+#else
+#if __has_attribute(visibility)
+#define DEMANGLE_ABI __attribute__((__visibility__("default")))
+#else
+#define DEMANGLE_ABI
+#endif
+#endif
+#endif
+
 #endif

llvm/include/llvm/Demangle/DemangleConfig.h

@@ -19,7 +19,6 @@
 #include "DemangleConfig.h"
 #include "StringViewExtras.h"
 #include "Utility.h"
-#include "Visibility.h"
 #include <algorithm>
 #include <cctype>
 #include <cstdint>

llvm/include/llvm/Demangle/ItaniumDemangle.h

@@ -10,8 +10,8 @@
 #define LLVM_DEMANGLE_MICROSOFTDEMANGLE_H
 
 #include "llvm/Demangle/Demangle.h"
+#include "llvm/Demangle/DemangleConfig.h"
 #include "llvm/Demangle/MicrosoftDemangleNodes.h"
-#include "llvm/Demangle/Visibility.h"
 
 #include <cassert>
 #include <string_view>

llvm/include/llvm/Demangle/MicrosoftDemangle.h

@@ -13,7 +13,7 @@
 #ifndef LLVM_DEMANGLE_MICROSOFTDEMANGLENODES_H
 #define LLVM_DEMANGLE_MICROSOFTDEMANGLENODES_H
 
-#include "Visibility.h"
+#include "DemangleConfig.h"
 #include <array>
 #include <cstdint>
 #include <string>