[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

1 files changed, 18 insertions, 23 deletions

diff --git a/llvm/tools/llvm-ifs/llvm-ifs.cpp b/llvm/tools/llvm-ifs/llvm-ifs.cpp
index 3b0d2ee..0d1a751 100644
--- a/llvm/tools/llvm-ifs/llvm-ifs.cpp
+++ b/llvm/tools/llvm-ifs/llvm-ifs.cpp
@@ -26,6 +26,7 @@
 #include "llvm/TextAPI/MachO/TextAPIWriter.h"
 #include <set>
 #include <string>
+#include <vector>
 
 using namespace llvm;
 using namespace llvm::yaml;
@@ -34,8 +35,8 @@ using namespace llvm::MachO;
 #define DEBUG_TYPE "llvm-ifs"
 
 namespace {
-const VersionTuple IFSVersionCurrent(1, 2);
-}
+const VersionTuple IFSVersionCurrent(2, 0);
+} // end anonymous namespace
 
 static cl::opt<std::string> Action("action", cl::desc("<llvm-ifs action>"),
                                    cl::value_desc("write-ifs | write-bin"),
@@ -76,6 +77,7 @@ std::string getTypeName(IFSSymbolType Type) {
 }
 
 struct IFSSymbol {
+  IFSSymbol() = default;
   IFSSymbol(std::string SymbolName) : Name(SymbolName) {}
   std::string Name;
   uint64_t Size;
@@ -85,6 +87,8 @@ struct IFSSymbol {
   bool operator<(const IFSSymbol &RHS) const { return Name < RHS.Name; }
 };
 
+LLVM_YAML_IS_SEQUENCE_VECTOR(IFSSymbol)
+
 namespace llvm {
 namespace yaml {
 /// YAML traits for IFSSymbolType.
@@ -124,6 +128,7 @@ template <> struct ScalarTraits<VersionTuple> {
 /// YAML traits for IFSSymbol.
 template <> struct MappingTraits<IFSSymbol> {
   static void mapping(IO &IO, IFSSymbol &Symbol) {
+    IO.mapRequired("Name", Symbol.Name);
     IO.mapRequired("Type", Symbol.Type);
     // The need for symbol size depends on the symbol type.
     if (Symbol.Type == IFSSymbolType::NoType)
@@ -140,20 +145,6 @@ template <> struct MappingTraits<IFSSymbol> {
   static const bool flow = true;
 };
 
-/// YAML traits for set of IFSSymbols.
-template <> struct CustomMappingTraits<std::set<IFSSymbol>> {
-  static void inputOne(IO &IO, StringRef Key, std::set<IFSSymbol> &Set) {
-    std::string Name = Key.str();
-    IFSSymbol Sym(Name);
-    IO.mapRequired(Name.c_str(), Sym);
-    Set.insert(Sym);
-  }
-
-  static void output(IO &IO, std::set<IFSSymbol> &Set) {
-    for (auto &Sym : Set)
-      IO.mapRequired(Sym.Name.c_str(), const_cast<IFSSymbol &>(Sym));
-  }
-};
 } // namespace yaml
 } // namespace llvm
 
@@ -167,7 +158,7 @@ public:
   std::string ObjectFileFormat;
   Optional<std::string> SOName;
   std::vector<std::string> NeededLibs;
-  std::set<IFSSymbol> Symbols;
+  std::vector<IFSSymbol> Symbols;
 
   IFSStub() = default;
   IFSStub(const IFSStub &Stub)
@@ -186,14 +177,18 @@ namespace yaml {
 /// YAML traits for IFSStub objects.
 template <> struct MappingTraits<IFSStub> {
   static void mapping(IO &IO, IFSStub &Stub) {
-    if (!IO.mapTag("!experimental-ifs-v1", true))
+    if (!IO.mapTag("!experimental-ifs-v2", true))
       IO.setError("Not a .ifs YAML file.");
+
+    auto OldContext = IO.getContext();
+    IO.setContext(&Stub);
     IO.mapRequired("IfsVersion", Stub.IfsVersion);
     IO.mapOptional("Triple", Stub.Triple);
     IO.mapOptional("ObjectFileFormat", Stub.ObjectFileFormat);
     IO.mapOptional("SOName", Stub.SOName);
     IO.mapOptional("NeededLibs", Stub.NeededLibs);
     IO.mapRequired("Symbols", Stub.Symbols);
+    IO.setContext(&OldContext);
   }
 };
 } // namespace yaml
@@ -218,7 +213,7 @@ static Expected<std::unique_ptr<IFSStub>> readInputFile(StringRef FilePath) {
   return std::move(Stub);
 }
 
-int writeTbdStub(const llvm::Triple &T, const std::set<IFSSymbol> &Symbols,
+int writeTbdStub(const llvm::Triple &T, const std::vector<IFSSymbol> &Symbols,
                  const StringRef Format, raw_ostream &Out) {
 
   auto PlatformKindOrError =
@@ -280,7 +275,7 @@ int writeTbdStub(const llvm::Triple &T, const std::set<IFSSymbol> &Symbols,
   return 0;
 }
 
-int writeElfStub(const llvm::Triple &T, const std::set<IFSSymbol> &Symbols,
+int writeElfStub(const llvm::Triple &T, const std::vector<IFSSymbol> &Symbols,
                  const StringRef Format, raw_ostream &Out) {
   SmallString<0> Storage;
   Storage.clear();
@@ -387,8 +382,8 @@ int writeIfso(const IFSStub &Stub, bool IsWriteIfs, raw_ostream &Out) {
 
 // TODO: Drop ObjectFileFormat, it can be subsumed from the triple.
 // New Interface Stubs Yaml Format:
-// --- !experimental-ifs-v1
-// IfsVersion:      1.0
+// --- !experimental-ifs-v2
+// IfsVersion: 2.0
 // Triple:          <llvm triple>
 // ObjectFileFormat: <ELF | others not yet supported>
 // Symbols:
@@ -517,7 +512,7 @@ int main(int argc, char *argv[]) {
     }
 
   for (auto &Entry : SymbolMap)
-    Stub.Symbols.insert(Entry.second);
+    Stub.Symbols.push_back(Entry.second);
 
   std::error_code SysErr;