Allow linking multiple bitcode files.

Linking options for particular file depend on the option that specifies the file.
Currently there are two:

* -mlink-bitcode-file links in complete content of the specified file.
* -mlink-cuda-bitcode links in only the symbols needed by current TU.
   Linked symbols are internalized. This bitcode linking mode is used to
   link device-specific bitcode provided by CUDA.

Files are linked in order they are specified on command line.

-mlink-cuda-bitcode replaces -fcuda-uses-libdevice flag.

Differential Revision: http://reviews.llvm.org/D13913

llvm-svn: 251427

clang/lib/Frontend/CompilerInvocation.cpp

@@ -25,6 +25,7 @@
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/ADT/Triple.h"
+#include "llvm/Linker/Linker.h"
 #include "llvm/Option/Arg.h"
 #include "llvm/Option/ArgList.h"
 #include "llvm/Option/OptTable.h"
@@ -539,7 +540,13 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
   Opts.EmitOpenCLArgMetadata = Args.hasArg(OPT_cl_kernel_arg_info);
   Opts.CompressDebugSections = Args.hasArg(OPT_compress_debug_sections);
   Opts.DebugCompilationDir = Args.getLastArgValue(OPT_fdebug_compilation_dir);
-  Opts.LinkBitcodeFile = Args.getLastArgValue(OPT_mlink_bitcode_file);
+  for (auto A : Args.filtered(OPT_mlink_bitcode_file, OPT_mlink_cuda_bitcode)) {
+    unsigned LinkFlags = llvm::Linker::Flags::None;
+    if (A->getOption().matches(OPT_mlink_cuda_bitcode))
+      LinkFlags = llvm::Linker::Flags::LinkOnlyNeeded |
+                  llvm::Linker::Flags::InternalizeLinkedSymbols;
+    Opts.LinkBitcodeFiles.push_back(std::make_pair(LinkFlags, A->getValue()));
+  }
   Opts.SanitizeCoverageType =
       getLastArgIntValue(Args, OPT_fsanitize_coverage_type, 0, Diags);
   Opts.SanitizeCoverageIndirectCalls =
@@ -1394,9 +1401,6 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
   if (Args.hasArg(OPT_fcuda_is_device))
     Opts.CUDAIsDevice = 1;
 
-  if (Args.hasArg(OPT_fcuda_uses_libdevice))
-    Opts.CUDAUsesLibDevice = 1;
-
   if (Args.hasArg(OPT_fcuda_allow_host_calls_from_host_device))
     Opts.CUDAAllowHostCallsFromHostDevice = 1;