Merge System into Support.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120298 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 68 insertions, 0 deletions

diff --git a/lib/Support/SearchForAddressOfSpecialSymbol.cpp b/lib/Support/SearchForAddressOfSpecialSymbol.cpp
new file mode 100644
index 0000000000..51ba417c21
--- /dev/null
+++ b/lib/Support/SearchForAddressOfSpecialSymbol.cpp
@@ -0,0 +1,68 @@
+//===- SearchForAddressOfSpecialSymbol.cpp - Function addresses -*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file pulls the addresses of certain symbols out of the linker.  It must
+//  include as few header files as possible because it declares the symbols as
+//  void*, which would conflict with the actual symbol type if any header
+//  declared it.
+//
+//===----------------------------------------------------------------------===//
+
+#include <string.h>
+
+// Must declare the symbols in the global namespace.
+static void *DoSearch(const char* symbolName) {
+#define EXPLICIT_SYMBOL(SYM) \
+   extern void *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(__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);
+
+    // __eprintf is sometimes used for assert() handling on x86.
+#ifdef __i386__
+    EXPLICIT_SYMBOL(__eprintf);
+#endif
+  }
+#endif
+
+#ifdef __CYGWIN__
+  {
+    EXPLICIT_SYMBOL(_alloca);
+    EXPLICIT_SYMBOL(__main);
+  }
+#endif
+
+#undef EXPLICIT_SYMBOL
+  return 0;
+}
+
+namespace llvm {
+void *SearchForAddressOfSpecialSymbol(const char* symbolName) {
+  return DoSearch(symbolName);
+}
+}  // namespace llvm