Tablegen: Remove the error for duplicate include files.

This error was originally added a while(7 years) ago when
including multiple files was basically always an error. Tablegen
now has preprocessor support, which allows for building nice
c/c++ style include guards. With the current error being
reported, we unfortunately need to double guard when including
files:

* In user of MyFile.td

 #ifndef MYFILE_TD
 include MyFile.td
 #endif

* In MyFile.td

 #ifndef MYFILE_TD
 #define MYFILE_TD
 ...
 #endif

Differential Revision: https://reviews.llvm.org/D70410

1 files changed, 5 insertions, 4 deletions

diff --git a/llvm/lib/TableGen/TGLexer.h b/llvm/lib/TableGen/TGLexer.h
index 266a9cd5d97..11a9bd303f5 100644
--- a/llvm/lib/TableGen/TGLexer.h
+++ b/llvm/lib/TableGen/TGLexer.h
@@ -19,8 +19,8 @@
 #include "llvm/Support/DataTypes.h"
 #include "llvm/Support/SMLoc.h"
 #include <cassert>
-#include <map>
 #include <memory>
+#include <set>
 #include <string>
 
 namespace llvm {
@@ -87,10 +87,11 @@ class TGLexer {
   unsigned CurBuffer = 0;
 
 public:
-  typedef std::map<std::string, SMLoc> DependenciesMapTy;
+  typedef std::set<std::string> DependenciesSetTy;
+
 private:
   /// Dependencies - This is the list of all included files.
-  DependenciesMapTy Dependencies;
+  DependenciesSetTy Dependencies;
 
 public:
   TGLexer(SourceMgr &SrcMgr, ArrayRef<std::string> Macros);
@@ -99,7 +100,7 @@ public:
     return CurCode = LexToken(CurPtr == CurBuf.begin());
   }
 
-  const DependenciesMapTy &getDependencies() const {
+  const DependenciesSetTy &getDependencies() const {
     return Dependencies;
   }