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

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: 373538

3 files changed, 77 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) {
diff --git a/clang/lib/Driver/ToolChains/InterfaceStubs.cpp b/clang/lib/Driver/ToolChains/InterfaceStubs.cpp
new file mode 100644
index 00000000000..6677843b2c5
--- /dev/null
+++ b/clang/lib/Driver/ToolChains/InterfaceStubs.cpp
@@ -0,0 +1,37 @@
+//===---  InterfaceStubs.cpp - Base InterfaceStubs Implementations C++  ---===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "InterfaceStubs.h"
+#include "CommonArgs.h"
+#include "clang/Driver/Compilation.h"
+
+namespace clang {
+namespace driver {
+namespace tools {
+namespace ifstool {
+void Merger::ConstructJob(Compilation &C, const JobAction &JA,
+                          const InputInfo &Output, const InputInfoList &Inputs,
+                          const llvm::opt::ArgList &Args,
+                          const char *LinkingOutput) const {
+  std::string Merger = getToolChain().GetProgramPath(getShortName());
+  llvm::opt::ArgStringList CmdArgs;
+  CmdArgs.push_back("-action");
+  CmdArgs.push_back(Args.getLastArg(options::OPT_emit_merged_ifs)
+                        ? "write-ifs"
+                        : "write-bin");
+  CmdArgs.push_back("-o");
+  CmdArgs.push_back(Output.getFilename());
+  for (const auto &Input : Inputs)
+    CmdArgs.push_back(Input.getFilename());
+  C.addCommand(std::make_unique<Command>(JA, *this, Args.MakeArgString(Merger),
+                                         CmdArgs, Inputs));
+}
+} // namespace ifstool
+} // namespace tools
+} // namespace driver
+} // namespace clang
diff --git a/clang/lib/Driver/ToolChains/InterfaceStubs.h b/clang/lib/Driver/ToolChains/InterfaceStubs.h
new file mode 100644
index 00000000000..4afa73701a4
--- /dev/null
+++ b/clang/lib/Driver/ToolChains/InterfaceStubs.h
@@ -0,0 +1,36 @@
+//===---  InterfaceStubs.cpp - Base InterfaceStubs Implementations C++  ---===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_IFS_H
+#define LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_IFS_H
+
+#include "clang/Driver/Tool.h"
+#include "clang/Driver/ToolChain.h"
+
+namespace clang {
+namespace driver {
+namespace tools {
+namespace ifstool {
+class LLVM_LIBRARY_VISIBILITY Merger : public Tool {
+public:
+  Merger(const ToolChain &TC) : Tool("IFS::Merger", "llvm-ifs", TC) {}
+
+  bool hasIntegratedCPP() const override { return false; }
+  bool isLinkJob() const override { return false; }
+
+  void ConstructJob(Compilation &C, const JobAction &JA,
+                    const InputInfo &Output, const InputInfoList &Inputs,
+                    const llvm::opt::ArgList &TCArgs,
+                    const char *LinkingOutput) const override;
+};
+} // end namespace ifstool
+} // end namespace tools
+} // end namespace driver
+} // end namespace clang
+
+#endif // LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_IFS_H