[PECOFF] Handle PRIVATE keyword in the module definition file

A symbol in a module definition file may be annotated with the
PRIVATE keyword like this.

  EXPORTS
    func PRIVATE

The PRIVATE keyword does not affect the resulting .dll file.
But it prevents the symbol to be listed in the .lib (import
library) file.

llvm-svn: 218273

lld/include/lld/Driver/WinLinkModuleDef.h

@@ -38,6 +38,7 @@ enum class Kind {
   kw_library,
   kw_name,
   kw_noname,
+  kw_private,
   kw_stacksize,
   kw_version,
 };

lld/include/lld/ReaderWriter/PECOFFLinkingContext.h

@@ -61,7 +61,8 @@ public:
   };
 
   struct ExportDesc {
-    ExportDesc() : ordinal(-1), noname(false), isData(false) {}
+    ExportDesc()
+        : ordinal(-1), noname(false), isData(false), isPrivate(false) {}
     bool operator<(const ExportDesc &other) const {
       return name.compare(other.name) < 0;
     }
@@ -71,6 +72,7 @@ public:
     int ordinal;
     bool noname;
     bool isData;
+    bool isPrivate;
   };
 
   /// \brief Casting support

lld/lib/Driver/WinLinkModuleDef.cpp

@@ -54,16 +54,17 @@ Token Lexer::lex() {
           "0123456789_.*~+!@#$%^&*()/");
       StringRef word = _buffer.substr(0, end);
       Kind kind = llvm::StringSwitch<Kind>(word)
-          .Case("BASE", Kind::kw_base)
-          .Case("DATA", Kind::kw_data)
-          .Case("EXPORTS", Kind::kw_exports)
-          .Case("HEAPSIZE", Kind::kw_heapsize)
-          .Case("LIBRARY", Kind::kw_library)
-          .Case("NAME", Kind::kw_name)
-          .Case("NONAME", Kind::kw_noname)
-          .Case("STACKSIZE", Kind::kw_stacksize)
-          .Case("VERSION", Kind::kw_version)
-          .Default(Kind::identifier);
+                      .Case("BASE", Kind::kw_base)
+                      .Case("DATA", Kind::kw_data)
+                      .Case("EXPORTS", Kind::kw_exports)
+                      .Case("HEAPSIZE", Kind::kw_heapsize)
+                      .Case("LIBRARY", Kind::kw_library)
+                      .Case("NAME", Kind::kw_name)
+                      .Case("NONAME", Kind::kw_noname)
+                      .Case("PRIVATE", Kind::kw_private)
+                      .Case("STACKSIZE", Kind::kw_stacksize)
+                      .Case("VERSION", Kind::kw_version)
+                      .Default(Kind::identifier);
       _buffer = (end == _buffer.npos) ? "" : _buffer.drop_front(end);
       return Token(kind, word);
     }
@@ -224,6 +225,10 @@ bool Parser::parseExport(PECOFFLinkingContext::ExportDesc &result) {
       result.isData = true;
       continue;
     }
+    if (_tok._kind == Kind::kw_private) {
+      result.isPrivate = true;
+      continue;
+    }
     ungetToken();
     return true;
   }

lld/lib/ReaderWriter/PECOFF/WriterImportLibrary.cpp

@@ -35,6 +35,8 @@ createModuleDefinitionFile(const PECOFFLinkingContext &ctx) {
       os << " NONAME";
     if (desc.isData)
       os << " DATA";
+    if (desc.isPrivate)
+      os << " PRIVATE";
     os << "\n";
   }
   os.flush();

lld/test/pecoff/Inputs/exports.def

@@ -3,4 +3,4 @@
 EXPORTS
   exportfn1 @5   ; foo
   exportfn2
-  exportfn5=exportfn6
+  exportfn5=exportfn6 PRIVATE