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, 30 insertions, 2 deletions

diff --git a/clang/lib/CodeGen/TargetInfo.cpp b/clang/lib/CodeGen/TargetInfo.cpp
index 32b27b3172a..45fc475e341 100644
--- a/clang/lib/CodeGen/TargetInfo.cpp
+++ b/clang/lib/CodeGen/TargetInfo.cpp
@@ -143,6 +143,16 @@ bool TargetCodeGenInfo::isNoProtoCallVariadic(const CallArgList &args,
   return false;
 }
 
+void
+TargetCodeGenInfo::getDependentLibraryOption(llvm::StringRef Lib,
+                                             llvm::SmallString<24> &Opt) const {
+  // This assumes the user is passing a library name like "rt" instead of a
+  // filename like "librt.a/so", and that they don't care whether it's static or
+  // dynamic.
+  Opt = "-l";
+  Opt += Lib;
+}
+
 static bool isEmptyRecord(ASTContext &Context, QualType T, bool AllowArrays);
 
 /// isEmptyField - Return true iff a the field is "empty", that is it
@@ -1256,6 +1266,18 @@ public:
 
 };
 
+class WinX86_32TargetCodeGenInfo : public X86_32TargetCodeGenInfo {
+public:
+  WinX86_32TargetCodeGenInfo(CodeGen::CodeGenTypes &CGT, unsigned RegParms)
+    : X86_32TargetCodeGenInfo(CGT, false, true, true, RegParms) {}
+
+  void getDependentLibraryOption(llvm::StringRef Lib,
+                                 llvm::SmallString<24> &Opt) const {
+    Opt = "/DEFAULTLIB:";
+    Opt += Lib;
+  }
+};
+
 class WinX86_64TargetCodeGenInfo : public TargetCodeGenInfo {
 public:
   WinX86_64TargetCodeGenInfo(CodeGen::CodeGenTypes &CGT)
@@ -1274,6 +1296,12 @@ public:
     AssignToArrayRange(CGF.Builder, Address, Eight8, 0, 16);
     return false;
   }
+
+  void getDependentLibraryOption(llvm::StringRef Lib,
+                                 llvm::SmallString<24> &Opt) const {
+    Opt = "/DEFAULTLIB:";
+    Opt += Lib;
+  }
 };
 
 }
@@ -5173,8 +5201,8 @@ const TargetCodeGenInfo &CodeGenModule::getTargetCodeGenInfo() {
 
     case llvm::Triple::Win32:
       return *(TheTargetCodeGenInfo =
-               new X86_32TargetCodeGenInfo(Types, false, true, true,
-                                           CodeGenOpts.NumRegisterParameters));
+               new WinX86_32TargetCodeGenInfo(Types,
+                                              CodeGenOpts.NumRegisterParameters));
 
     default:
       return *(TheTargetCodeGenInfo =