[clang-ifs] Clang Interface Stubs, first version (second landing attempt).

This change reverts r363649; effectively re-landing r363626. At this point
clang::Index::CodegenNameGeneratorImpl has been refactored into
clang::AST::ASTNameGenerator. This makes it so that the previous circular link
dependency no longer exists, fixing the previous share lib
(-DBUILD_SHARED_LIBS=ON) build issue which was the reason for r363649.

Clang interface stubs (previously referred to as clang-ifsos) is a new frontend
action in clang that allows the generation of stub files that contain mangled
name info that can be used to produce a stub library. These stub libraries can
be useful for breaking up build dependencies and controlling access to a
library's internal symbols. Generation of these stubs can be invoked by:

clang -fvisibility=<visibility> -emit-interface-stubs \
                                -interface-stub-version=<interface format>

Notice that -fvisibility (along with use of visibility attributes) can be used
to control what symbols get generated. Currently the interface format is
experimental but there are a wide range of possibilities here.

Currently clang-ifs produces .ifs files that can be thought of as analogous to
object (.o) files, but just for the mangled symbol info. In a subsequent patch
I intend to add support for merging the .ifs files into one .ifs/.ifso file
that can be the input to something like llvm-elfabi to produce something like a
.so file or .dll (but without any of the code, just symbols).

Differential Revision: https://reviews.llvm.org/D60974

llvm-svn: 363948

1 files changed, 21 insertions, 0 deletions

diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index d36af28..b90950f 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -1681,6 +1681,25 @@ static InputKind ParseFrontendArgs(FrontendOptions &Opts, ArgList &Args,
       Opts.ProgramAction = frontend::GenerateHeaderModule; break;
     case OPT_emit_pch:
       Opts.ProgramAction = frontend::GeneratePCH; break;
+    case OPT_emit_iterface_stubs: {
+      llvm::Optional<frontend::ActionKind> ProgramAction =
+          llvm::StringSwitch<llvm::Optional<frontend::ActionKind>>(
+              Args.hasArg(OPT_iterface_stub_version_EQ)
+                  ? Args.getLastArgValue(OPT_iterface_stub_version_EQ)
+                  : "")
+              .Case("experimental-yaml-elf-v1",
+                    frontend::GenerateInterfaceYAMLExpV1)
+              .Case("experimental-tapi-elf-v1",
+                    frontend::GenerateInterfaceTBEExpV1)
+              .Default(llvm::None);
+      if (!ProgramAction)
+        Diags.Report(diag::err_drv_invalid_value)
+            << "Must specify a valid interface stub format type using "
+            << "-interface-stub-version=<experimental-tapi-elf-v1 | "
+               "experimental-yaml-elf-v1>";
+      Opts.ProgramAction = *ProgramAction;
+      break;
+    }
     case OPT_init_only:
       Opts.ProgramAction = frontend::InitOnly; break;
     case OPT_fsyntax_only:
@@ -3119,6 +3138,8 @@ static bool isStrictlyPreprocessorAction(frontend::ActionKind Action) {
   case frontend::GenerateModuleInterface:
   case frontend::GenerateHeaderModule:
   case frontend::GeneratePCH:
+  case frontend::GenerateInterfaceYAMLExpV1:
+  case frontend::GenerateInterfaceTBEExpV1:
   case frontend::ParseSyntaxOnly:
   case frontend::ModuleFileInfo:
   case frontend::VerifyPCH: