Move the extern symbol declarations outside of

DynamicLibrary::SearchForAddressOfSymbol and force them to have "C"
linkage. 

Interestingly, GCC treats the block-scoped "extern" declarations we
previously had as if they were extern "C" declarations (or, at least,
were in the global namespace), so that GCC bug papered over this LLVM
bug. Clang and EDG get the linkage correct; this new variant seems to
work for both GCC and Clang.

llvm-svn: 92020

2 files changed, 47 insertions, 28 deletions

diff --git a/llvm/lib/System/DynamicLibrary.cpp b/llvm/lib/System/DynamicLibrary.cpp
index 7eb9f5f3ef8..b511a3cad20 100644
--- a/llvm/lib/System/DynamicLibrary.cpp
+++ b/llvm/lib/System/DynamicLibrary.cpp
@@ -69,6 +69,10 @@ bool DynamicLibrary::LoadLibraryPermanently(const char *Filename,
   return false;
 }
 
+#define EXPLICIT_SYMBOL(SYM) \
+  extern "C" void *SYM;
+#include "DynamicLibrarySymbolDefs.def"
+
 void* DynamicLibrary::SearchForAddressOfSymbol(const char* symbolName) {
   // First check symbols added via AddSymbol().
   if (ExplicitSymbols) {
@@ -93,41 +97,15 @@ void* DynamicLibrary::SearchForAddressOfSymbol(const char* symbolName) {
   }
 
 #define EXPLICIT_SYMBOL(SYM) \
-   extern void *SYM; if (!strcmp(symbolName, #SYM)) return &SYM
+   if (!strcmp(symbolName, #SYM)) return &SYM;
 
   // If this is darwin, it has some funky issues, try to solve them here.  Some
   // important symbols are marked 'private external' which doesn't allow
   // SearchForAddressOfSymbol to find them.  As such, we special case them here,
   // there is only a small handful of them.
-
-#ifdef __APPLE__
-  {
-    EXPLICIT_SYMBOL(__ashldi3);
-    EXPLICIT_SYMBOL(__ashrdi3);
-    EXPLICIT_SYMBOL(__cmpdi2);
-    EXPLICIT_SYMBOL(__divdi3);
-    EXPLICIT_SYMBOL(__eprintf);
-    EXPLICIT_SYMBOL(__fixdfdi);
-    EXPLICIT_SYMBOL(__fixsfdi);
-    EXPLICIT_SYMBOL(__fixunsdfdi);
-    EXPLICIT_SYMBOL(__fixunssfdi);
-    EXPLICIT_SYMBOL(__floatdidf);
-    EXPLICIT_SYMBOL(__floatdisf);
-    EXPLICIT_SYMBOL(__lshrdi3);
-    EXPLICIT_SYMBOL(__moddi3);
-    EXPLICIT_SYMBOL(__udivdi3);
-    EXPLICIT_SYMBOL(__umoddi3);
-  }
-#endif
-
-#ifdef __CYGWIN__
   {
-    EXPLICIT_SYMBOL(_alloca);
-    EXPLICIT_SYMBOL(__main);
+#include "DynamicLibrarySymbolDefs.def"
   }
-#endif
-
-#undef EXPLICIT_SYMBOL
 
 // This macro returns the address of a well-known, explicit symbol
 #define EXPLICIT_SYMBOL(SYM) \
diff --git a/llvm/lib/System/DynamicLibrarySymbolDefs.def b/llvm/lib/System/DynamicLibrarySymbolDefs.def
new file mode 100644
index 00000000000..c012916534b
--- /dev/null
+++ b/llvm/lib/System/DynamicLibrarySymbolDefs.def
@@ -0,0 +1,41 @@
+//===-- DynamicLibrarySymbolDefs.def - Extra symbol definitions -*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file enumerates the set of extra external symbol definitions needed for
+//  dynamic libraries.
+//
+//===----------------------------------------------------------------------===//
+#ifndef EXPLICIT_SYMBOL
+#  error Must define EXPLICIT_SYMBOL to include this definitions file
+#endif
+
+#ifdef __APPLE__
+EXPLICIT_SYMBOL(__ashldi3)
+EXPLICIT_SYMBOL(__ashrdi3)
+EXPLICIT_SYMBOL(__cmpdi2)
+EXPLICIT_SYMBOL(__divdi3)
+EXPLICIT_SYMBOL(__eprintf)
+EXPLICIT_SYMBOL(__fixdfdi)
+EXPLICIT_SYMBOL(__fixsfdi)
+EXPLICIT_SYMBOL(__fixunsdfdi)
+EXPLICIT_SYMBOL(__fixunssfdi)
+EXPLICIT_SYMBOL(__floatdidf)
+EXPLICIT_SYMBOL(__floatdisf)
+EXPLICIT_SYMBOL(__lshrdi3)
+EXPLICIT_SYMBOL(__moddi3)
+EXPLICIT_SYMBOL(__udivdi3)
+EXPLICIT_SYMBOL(__umoddi3)
+#endif
+
+#ifdef __CYGWIN__
+EXPLICIT_SYMBOL(_alloca)
+EXPLICIT_SYMBOL(__main)
+#endif
+
+#undef EXPLICIT_SYMBOL