[clang-ifs] Clang Interface Stubs, first version (second landing atte…

…mpt).

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

clang/include/clang/Basic/DiagnosticFrontendKinds.td

@@ -220,6 +220,8 @@ def err_module_header_file_not_found :
 def err_module_header_file_invalid :
   Error<"unexpected module header file input '%0'">, DefaultFatal;
 
+def err_interface_stubs : Error<"clang-ifs (-emit-iterface-stubs): %0">;
+
 def err_test_module_file_extension_version : Error<
   "test module file extension '%0' has different version (%1.%2) than expected "
   "(%3.%4)">;

clang/include/clang/Driver/Options.td

@@ -623,6 +623,9 @@ def emit_ast : Flag<["-"], "emit-ast">,
   HelpText<"Emit Clang AST files for source inputs">;
 def emit_llvm : Flag<["-"], "emit-llvm">, Flags<[CC1Option]>, Group<Action_Group>,
   HelpText<"Use the LLVM representation for assembler and object files">;
+def emit_iterface_stubs : Flag<["-"], "emit-interface-stubs">, Flags<[CC1Option]>, Group<Action_Group>,
+  HelpText<"Generate Inteface Stub Files.">;
+def iterface_stub_version_EQ : JoinedOrSeparate<["-"], "interface-stub-version=">, Flags<[CC1Option]>;
 def exported__symbols__list : Separate<["-"], "exported_symbols_list">;
 def e : JoinedOrSeparate<["-"], "e">, Group<Link_Group>;
 def fPIC : Flag<["-"], "fPIC">, Group<f_Group>;

clang/include/clang/Driver/Types.def

@@ -88,6 +88,7 @@ TYPE("lto-bc",                   LTO_BC,       INVALID,         "o",     "")
 
 // Misc.
 TYPE("ast",                      AST,          INVALID,         "ast",   "u")
+TYPE("ifs",                      IFS,          INVALID,         "ifs",   "u")
 TYPE("pcm",                      ModuleFile,   INVALID,         "pcm",   "u")
 TYPE("plist",                    Plist,        INVALID,         "plist", "")
 TYPE("rewritten-objc",           RewrittenObjC,INVALID,         "cpp",   "")

clang/include/clang/Frontend/FrontendActions.h

@@ -119,6 +119,26 @@ class GenerateModuleAction : public ASTFrontendAction {
   bool hasASTFileSupport() const override { return false; }
 };
 
+class GenerateInterfaceStubAction : public ASTFrontendAction {
+protected:
+  TranslationUnitKind getTranslationUnitKind() override { return TU_Module; }
+
+  bool hasASTFileSupport() const override { return false; }
+};
+
+// Support different interface stub formats this way:
+class GenerateInterfaceYAMLExpV1Action : public GenerateInterfaceStubAction {
+protected:
+  std::unique_ptr<ASTConsumer> CreateASTConsumer(CompilerInstance &CI,
+                                                 StringRef InFile) override;
+};
+
+class GenerateInterfaceTBEExpV1Action : public GenerateInterfaceStubAction {
+protected:
+  std::unique_ptr<ASTConsumer> CreateASTConsumer(CompilerInstance &CI,
+                                                 StringRef InFile) override;
+};
+
 class GenerateModuleFromModuleMapAction : public GenerateModuleAction {
 private:
   bool BeginSourceFileAction(CompilerInstance &CI) override;

clang/include/clang/Frontend/FrontendOptions.h

@@ -88,6 +88,10 @@ enum ActionKind {
   /// Generate pre-compiled header.
   GeneratePCH,
 
+  /// Generate Interface Stub Files.
+  GenerateInterfaceYAMLExpV1,
+  GenerateInterfaceTBEExpV1,
+
   /// Only execute frontend initialization.
   InitOnly,
 

clang/lib/Driver/Driver.cpp

@@ -285,6 +285,7 @@ phases::ID Driver::getFinalPhase(const DerivedArgList &DAL,
              (PhaseArg = DAL.getLastArg(options::OPT_rewrite_objc)) ||
              (PhaseArg = DAL.getLastArg(options::OPT_rewrite_legacy_objc)) ||
              (PhaseArg = DAL.getLastArg(options::OPT__migrate)) ||
+             (PhaseArg = DAL.getLastArg(options::OPT_emit_iterface_stubs)) ||
              (PhaseArg = DAL.getLastArg(options::OPT__analyze,
                                         options::OPT__analyze_auto)) ||
              (PhaseArg = DAL.getLastArg(options::OPT_emit_ast))) {
@@ -3472,6 +3473,8 @@ Action *Driver::ConstructPhaseAction(
       return C.MakeAction<CompileJobAction>(Input, types::TY_ModuleFile);
     if (Args.hasArg(options::OPT_verify_pch))
       return C.MakeAction<VerifyPCHJobAction>(Input, types::TY_Nothing);
+    if (Args.hasArg(options::OPT_emit_iterface_stubs))
+      return C.MakeAction<CompileJobAction>(Input, types::TY_IFS);
     return C.MakeAction<CompileJobAction>(Input, types::TY_LLVM_BC);
   }
   case phases::Backend: {

clang/lib/Driver/ToolChains/Clang.cpp

@@ -3613,6 +3613,25 @@ 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) {
+      StringRef StubFormat =
+          llvm::StringSwitch<StringRef>(
+              Args.hasArg(options::OPT_iterface_stub_version_EQ)
+                  ? Args.getLastArgValue(options::OPT_iterface_stub_version_EQ)
+                  : "")
+              .Case("experimental-yaml-elf-v1", "experimental-yaml-elf-v1")
+              .Case("experimental-tapi-elf-v1", "experimental-tapi-elf-v1")
+              .Default("");
+
+      if (StubFormat.empty())
+        D.Diag(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>";
+
+      CmdArgs.push_back("-emit-interface-stubs");
+      CmdArgs.push_back(
+          Args.MakeArgString(Twine("-interface-stub-version=") + StubFormat));
     } else if (JA.getType() == types::TY_PP_Asm) {
       CmdArgs.push_back("-S");
     } else if (JA.getType() == types::TY_AST) {

clang/lib/Frontend/CMakeLists.txt

@@ -45,6 +45,7 @@ add_clang_library(clangFrontend
   TextDiagnosticBuffer.cpp
   TextDiagnosticPrinter.cpp
   VerifyDiagnosticConsumer.cpp
+  InterfaceStubFunctionsConsumer.cpp
 
   DEPENDS
   ClangDriverOptions

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: