[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, 12 insertions, 11 deletions

diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 61a2c07890f..6fc8afcf3c6 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -1734,24 +1734,25 @@ static InputKind ParseFrontendArgs(FrontendOptions &Opts, ArgList &Args,
       StringRef ArgStr =
           Args.hasArg(OPT_iterface_stub_version_EQ)
               ? Args.getLastArgValue(OPT_iterface_stub_version_EQ)
-              : "";
-      llvm::Optional<frontend::ActionKind> ProgramAction =
-          llvm::StringSwitch<llvm::Optional<frontend::ActionKind>>(ArgStr)
-              .Case("experimental-ifs-v1", frontend::GenerateInterfaceIfsExpV1)
-              .Default(llvm::None);
-      if (!ProgramAction) {
+              : "experimental-ifs-v1";
+      if (ArgStr == "experimental-yaml-elf-v1" ||
+          ArgStr == "experimental-tapi-elf-v1") {
         std::string ErrorMessage =
             "Invalid interface stub format: " + ArgStr.str() +
-            ((ArgStr == "experimental-yaml-elf-v1" ||
-              ArgStr == "experimental-tapi-elf-v1")
-                 ? " is deprecated."
-                 : ".");
+            " is deprecated.";
+        Diags.Report(diag::err_drv_invalid_value)
+            << "Must specify a valid interface stub format type, ie: "
+               "-interface-stub-version=experimental-ifs-v1"
+            << ErrorMessage;
+      } else if (ArgStr != "experimental-ifs-v1") {
+        std::string ErrorMessage =
+            "Invalid interface stub format: " + ArgStr.str() + ".";
         Diags.Report(diag::err_drv_invalid_value)
             << "Must specify a valid interface stub format type, ie: "
                "-interface-stub-version=experimental-ifs-v1"
             << ErrorMessage;
       } else {
-        Opts.ProgramAction = *ProgramAction;
+        Opts.ProgramAction = frontend::GenerateInterfaceIfsExpV1;
       }
       break;
     }