[llvm][clang][IFS] Enhancing the llvm-ifs yaml format for symbol lists.

Prior to this change the clang interface stubs format resembled
something ending with a symbol list like this:

 Symbols:
   a: { Type: Func }

This was problematic because we didn't actually want a map format and
also because we didn't like that an empty symbol list required
"Symbols: {}". That is to say without the empty {} llvm-ifs would crash
on an empty list.

With this new format it is much more clear which field is the symbol
name, and instead the [] that is used to express an empty symbol vector
is optional, ie:

Symbols:
 - { Name: a, Type: Func }

or

Symbols: []

or

Symbols:

This further diverges the format from existing llvm-elftapi. This is a
good thing because although the format originally came from the same
place, they are not the same in any way.

Differential Revision: https://reviews.llvm.org/D76979

Author: plotfi

clang/include/clang/Frontend/FrontendActions.h

@@ -119,17 +119,13 @@ 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; }
-};
-
-class GenerateInterfaceIfsExpV1Action : public GenerateInterfaceStubAction {
+class GenerateInterfaceStubsAction : public ASTFrontendAction {
 protected:
   std::unique_ptr<ASTConsumer> CreateASTConsumer(CompilerInstance &CI,
                                                  StringRef InFile) override;
+
+  TranslationUnitKind getTranslationUnitKind() override { return TU_Module; }
+  bool hasASTFileSupport() const override { return false; }
 };
 
 class GenerateModuleFromModuleMapAction : public GenerateModuleAction {

clang/include/clang/Frontend/FrontendOptions.h

@@ -90,7 +90,7 @@ enum ActionKind {
   GeneratePCH,
 
   /// Generate Interface Stub Files.
-  GenerateInterfaceIfsExpV1,
+  GenerateInterfaceStubs,
 
   /// Only execute frontend initialization.
   InitOnly,

clang/lib/Driver/ToolChains/Clang.cpp

@@ -4184,7 +4184,7 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
       StringRef ArgStr =
           Args.hasArg(options::OPT_interface_stub_version_EQ)
               ? Args.getLastArgValue(options::OPT_interface_stub_version_EQ)
-              : "experimental-ifs-v1";
+              : "experimental-ifs-v2";
       CmdArgs.push_back("-emit-interface-stubs");
       CmdArgs.push_back(
           Args.MakeArgString(Twine("-interface-stub-version=") + ArgStr.str()));

clang/lib/Frontend/CompilerInvocation.cpp

@@ -1780,25 +1780,26 @@ static InputKind ParseFrontendArgs(FrontendOptions &Opts, ArgList &Args,
       StringRef ArgStr =
           Args.hasArg(OPT_interface_stub_version_EQ)
               ? Args.getLastArgValue(OPT_interface_stub_version_EQ)
-              : "experimental-ifs-v1";
+              : "experimental-ifs-v2";
       if (ArgStr == "experimental-yaml-elf-v1" ||
+          ArgStr == "experimental-ifs-v1" ||
           ArgStr == "experimental-tapi-elf-v1") {
         std::string ErrorMessage =
             "Invalid interface stub format: " + ArgStr.str() +
             " is deprecated.";
         Diags.Report(diag::err_drv_invalid_value)
             << "Must specify a valid interface stub format type, ie: "
-               "-interface-stub-version=experimental-ifs-v1"
+               "-interface-stub-version=experimental-ifs-v2"
             << ErrorMessage;
-      } else if (ArgStr != "experimental-ifs-v1") {
+      } else if (!ArgStr.startswith("experimental-ifs-")) {
         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"
+               "-interface-stub-version=experimental-ifs-v2"
             << ErrorMessage;
       } else {
-        Opts.ProgramAction = frontend::GenerateInterfaceIfsExpV1;
+        Opts.ProgramAction = frontend::GenerateInterfaceStubs;
       }
       break;
     }
@@ -3367,7 +3368,7 @@ static bool isStrictlyPreprocessorAction(frontend::ActionKind Action) {
   case frontend::GenerateModuleInterface:
   case frontend::GenerateHeaderModule:
   case frontend::GeneratePCH:
-  case frontend::GenerateInterfaceIfsExpV1:
+  case frontend::GenerateInterfaceStubs:
   case frontend::ParseSyntaxOnly:
   case frontend::ModuleFileInfo:
   case frontend::VerifyPCH:

clang/lib/Frontend/InterfaceStubFunctionsConsumer.cpp

@@ -290,7 +290,7 @@ class InterfaceStubFunctionsConsumer : public ASTConsumer {
                              const ASTContext &context, StringRef Format,
                              raw_ostream &OS) -> void {
       OS << "--- !" << Format << "\n";
-      OS << "IfsVersion: 1.0\n";
+      OS << "IfsVersion: 2.0\n";
       OS << "Triple: " << T.str() << "\n";
       OS << "ObjectFileFormat: "
          << "ELF"
@@ -299,11 +299,11 @@ class InterfaceStubFunctionsConsumer : public ASTConsumer {
       for (const auto &E : Symbols) {
         const MangledSymbol &Symbol = E.second;
         for (auto Name : Symbol.Names) {
-          OS << "  \""
+          OS << "  - { Name: \""
              << (Symbol.ParentName.empty() || Instance.getLangOpts().CPlusPlus
                      ? ""
                      : (Symbol.ParentName + "."))
-             << Name << "\" : { Type: ";
+             << Name << "\", Type: ";
           switch (Symbol.Type) {
           default:
             llvm_unreachable(
@@ -330,15 +330,15 @@ class InterfaceStubFunctionsConsumer : public ASTConsumer {
       OS.flush();
     };
 
-    assert(Format == "experimental-ifs-v1" && "Unexpected IFS Format.");
+    assert(Format == "experimental-ifs-v2" && "Unexpected IFS Format.");
     writeIfsV1(Instance.getTarget().getTriple(), Symbols, context, Format, *OS);
   }
 };
 } // namespace
 
 std::unique_ptr<ASTConsumer>
-GenerateInterfaceIfsExpV1Action::CreateASTConsumer(CompilerInstance &CI,
-                                                   StringRef InFile) {
+GenerateInterfaceStubsAction::CreateASTConsumer(CompilerInstance &CI,
+                                                StringRef InFile) {
   return std::make_unique<InterfaceStubFunctionsConsumer>(
-      CI, InFile, "experimental-ifs-v1");
+      CI, InFile, "experimental-ifs-v2");
 }

clang/lib/FrontendTool/ExecuteCompilerInvocation.cpp

@@ -65,8 +65,8 @@ CreateFrontendBaseAction(CompilerInstance &CI) {
   case GenerateHeaderModule:
     return std::make_unique<GenerateHeaderModuleAction>();
   case GeneratePCH:            return std::make_unique<GeneratePCHAction>();
-  case GenerateInterfaceIfsExpV1:
-    return std::make_unique<GenerateInterfaceIfsExpV1Action>();
+  case GenerateInterfaceStubs:
+    return std::make_unique<GenerateInterfaceStubsAction>();
   case InitOnly:               return std::make_unique<InitOnlyAction>();
   case ParseSyntaxOnly:        return std::make_unique<SyntaxOnlyAction>();
   case ModuleFileInfo:         return std::make_unique<DumpModuleInfoAction>();

clang/test/InterfaceStubs/bad-format.cpp

@@ -7,6 +7,9 @@
 // RUN: not %clang -emit-interface-stubs -interface-stub-version=experimental-yaml-elf-v1 %s 2>&1 | \
 // RUN: FileCheck -check-prefix=CHECK-YAML-DEPRECATED %s
 
+// RUN: not %clang -emit-interface-stubs -interface-stub-version=experimental-ifs-v1 %s 2>&1 | \
+// RUN: FileCheck -check-prefix=CHECK-V1-DEPRECATED %s
+
 // RUN: not %clang -emit-interface-stubs -interface-stub-version=bad-format %s 2>&1 | \
 // RUN: FileCheck %s
 
@@ -21,16 +24,22 @@
 // CHECK: error: invalid value
 // CHECK: 'Invalid interface stub format: bad-format.' in 'Must specify a
 // CHECK: valid interface stub format type, ie:
-// CHECK: -interface-stub-version=experimental-ifs-v1'
+// CHECK: -interface-stub-version=experimental-ifs-v2'
 
 // CHECK-TAPI-DEPRECATED: error: invalid value
 // CHECK-TAPI-DEPRECATED: 'Invalid interface stub format:
 // CHECK-TAPI-DEPRECATED: experimental-tapi-elf-v1 is deprecated.' in 'Must
 // CHECK-TAPI-DEPRECATED: specify a valid interface stub format type, ie:
-// CHECK-TAPI-DEPRECATED: -interface-stub-version=experimental-ifs-v1'
+// CHECK-TAPI-DEPRECATED: -interface-stub-version=experimental-ifs-v2'
 
 // CHECK-YAML-DEPRECATED: error: invalid value
 // CHECK-YAML-DEPRECATED: 'Invalid interface stub format:
 // CHECK-YAML-DEPRECATED: experimental-yaml-elf-v1 is deprecated.' in 'Must
 // CHECK-YAML-DEPRECATED: specify a valid interface stub format type, ie:
-// CHECK-YAML-DEPRECATED: -interface-stub-version=experimental-ifs-v1'
+// CHECK-YAML-DEPRECATED: -interface-stub-version=experimental-ifs-v2'
+
+// CHECK-V1-DEPRECATED: error: invalid value
+// CHECK-V1-DEPRECATED: 'Invalid interface stub format:
+// CHECK-V1-DEPRECATED: experimental-ifs-v1 is deprecated.' in 'Must
+// CHECK-V1-DEPRECATED: specify a valid interface stub format type, ie:
+// CHECK-V1-DEPRECATED: -interface-stub-version=experimental-ifs-v2'

clang/test/InterfaceStubs/blocks.c

@@ -1,7 +1,7 @@
 // RUN: %clang_cc1 -emit-interface-stubs -fblocks -o - %s | FileCheck %s
 
-// CHECK: --- !experimental-ifs-v1
-// CHECK-NEXT: IfsVersion: 1.0
+// CHECK: --- !experimental-ifs-v2
+// CHECK-NEXT: IfsVersion: 2.0
 // CHECK-NEXT: Triple:
 // CHECK-NEXT: ObjectFileFormat: ELF
 // CHECK-NEXT: Symbols:

clang/test/InterfaceStubs/class-template-partial-specialization.cpp

@@ -1,7 +1,7 @@
 // RUN: %clang_cc1 -o - -emit-interface-stubs %s | FileCheck %s
 
-// CHECK:      --- !experimental-ifs-v1
-// CHECK-NEXT: IfsVersion: 1.0
+// CHECK:      --- !experimental-ifs-v2
+// CHECK-NEXT: IfsVersion: 2.0
 // CHECK-NEXT: Triple:
 // CHECK-NEXT: ObjectFileFormat: ELF
 // CHECK-NEXT: Symbols:

clang/test/InterfaceStubs/conflict-type.ifs

@@ -7,10 +7,10 @@
 # CHECK-IFS-NEXT: Filename:
 # CHECK-IFS-NEXT: Type Values: Object Func
 
---- !experimental-ifs-v1
-IfsVersion: 1.0
+--- !experimental-ifs-v2
+IfsVersion: 2.0
 Triple: x86_64-linux-gnu
 ObjectFileFormat: ELF
 Symbols:
-  a: { Type: Object, Size: 1 }
+  - { Name: a, Type: Object, Size: 1 }
 ...