Forward #pragma comment(lib/linker) through as flags metadata

Summary:
Most of this change is wiring the pragma all the way through from the
lexer, parser, and sema to codegen.  I considered adding a Decl AST node
for this, but it seemed too heavyweight.

Mach-O already uses a metadata flag called "Linker Options" to do this
kind of auto-linking.  This change follows that pattern.

LLVM knows how to forward the "Linker Options" metadata into the COFF
.drectve section where these flags belong.  ELF support is not
implemented, but possible.

This is related to auto-linking, which is http://llvm.org/PR13016.

CC: cfe-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D723

llvm-svn: 181426

1 files changed, 6 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/TargetInfo.h b/clang/lib/CodeGen/TargetInfo.h
index bb50ce69e31..dee7fd8dd40 100644
--- a/clang/lib/CodeGen/TargetInfo.h
+++ b/clang/lib/CodeGen/TargetInfo.h
@@ -18,6 +18,7 @@
 #include "clang/AST/Type.h"
 #include "clang/Basic/LLVM.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/SmallString.h"
 
 namespace llvm {
   class GlobalValue;
@@ -167,6 +168,11 @@ namespace clang {
     /// that unprototyped calls to varargs functions still succeed.
     virtual bool isNoProtoCallVariadic(const CodeGen::CallArgList &args,
                                        const FunctionNoProtoType *fnType) const;
+
+    /// Gets the linker options necessary to link a dependent library on this
+    /// platform.
+    virtual void getDependentLibraryOption(llvm::StringRef Lib,
+                                           llvm::SmallString<24> &Opt) const;
   };
 }