[clang][ifs] Clang Interface Stubs ToolChain plumbing.

Second Landing Attempt:

This patch enables end to end support for generating ELF interface stubs
directly from clang. Now the following:

clang -emit-interface-stubs -o libfoo.so a.cpp b.cpp c.cpp

will product an ELF binary with visible symbols populated. Visibility attributes
and -fvisibility can be used to control what gets populated.

* Adding ToolChain support for clang Driver IFS Merge Phase
* Implementing a default InterfaceStubs Merge clang Tool, used by ToolChain
* Adds support for the clang Driver to involve llvm-ifs on ifs files.
* Adds -emit-merged-ifs flag, to tell llvm-ifs to emit a merged ifs text file
  instead of the final object format (normally ELF)


Differential Revision: https://reviews.llvm.org/D63978

llvm-svn: 374061

1 files changed, 4 insertions, 21 deletions

diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index 8628741f7da..26e8bc60bfa 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -3683,32 +3683,15 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
     } else if (JA.getType() == types::TY_LLVM_BC ||
                JA.getType() == types::TY_LTO_BC) {
       CmdArgs.push_back("-emit-llvm-bc");
-    } else if (JA.getType() == types::TY_IFS) {
+    } else if (JA.getType() == types::TY_IFS ||
+               JA.getType() == types::TY_IFS_CPP) {
       StringRef ArgStr =
           Args.hasArg(options::OPT_iterface_stub_version_EQ)
               ? Args.getLastArgValue(options::OPT_iterface_stub_version_EQ)
-              : "";
-      StringRef StubFormat =
-          llvm::StringSwitch<StringRef>(ArgStr)
-              .Case("experimental-ifs-v1", "experimental-ifs-v1")
-              .Default("");
-
-      if (StubFormat.empty()) {
-        std::string ErrorMessage =
-            "Invalid interface stub format: " + ArgStr.str() +
-            ((ArgStr == "experimental-yaml-elf-v1" ||
-              ArgStr == "experimental-tapi-elf-v1")
-                 ? " is deprecated."
-                 : ".");
-        D.Diag(diag::err_drv_invalid_value)
-            << "Must specify a valid interface stub format type, ie: "
-               "-interface-stub-version=experimental-ifs-v1"
-            << ErrorMessage;
-      }
-
+              : "experimental-ifs-v1";
       CmdArgs.push_back("-emit-interface-stubs");
       CmdArgs.push_back(
-          Args.MakeArgString(Twine("-interface-stub-version=") + StubFormat));
+          Args.MakeArgString(Twine("-interface-stub-version=") + ArgStr.str()));
     } else if (JA.getType() == types::TY_PP_Asm) {
       CmdArgs.push_back("-S");
     } else if (JA.getType() == types::TY_AST) {