tblgen: Diagnose duplicate includes.

A double inclusion will pretty much always be an error in TableGen, so
there's no point going on just to die with "def already defined" or
whatnot.

I'm not too thrilled about the "public: ... private: ..." to expose the
DependenciesMapTy, but I really didn't see a better way to keep that
type centralized. It's a smell that indicates that some refactoring is
needed to make this code more loosely coupled.

This should avoid all bugs of the same nature as PR15189.

llvm-svn: 174582

lib/TableGen/Main.cpp

@@ -64,11 +64,11 @@ static int createDependencyFile(const TGParser &Parser, const char *argv0) {
     return 1;
   }
   DepOut.os() << OutputFilename << ":";
-  const std::vector<std::string> &Dependencies = Parser.getDependencies();
-  for (std::vector<std::string>::const_iterator I = Dependencies.begin(),
-                                                E = Dependencies.end();
+  const TGLexer::DependenciesMapTy &Dependencies = Parser.getDependencies();
+  for (TGLexer::DependenciesMapTy::const_iterator I = Dependencies.begin(),
+                                                  E = Dependencies.end();
        I != E; ++I) {
-    DepOut.os() << " " << (*I);
+    DepOut.os() << " " << I->first;
   }
   DepOut.os() << "\n";
   DepOut.keep();

lib/TableGen/TGLexer.cpp

@@ -309,7 +309,15 @@ bool TGLexer::LexInclude() {
     return true;
   }
   
-  Dependencies.push_back(IncludedFile);
+  DependenciesMapTy::const_iterator Found = Dependencies.find(IncludedFile);
+  if (Found != Dependencies.end()) {
+    PrintError(getLoc(),
+               "File '" + IncludedFile + "' has already been included.");
+    SrcMgr.PrintMessage(Found->second, SourceMgr::DK_Note,
+                        "previously included here");
+    return true;
+  }
+  Dependencies.insert(std::make_pair(IncludedFile, getLoc()));
   // Save the line number and lex buffer of the includer.
   CurBuf = SrcMgr.getMemoryBuffer(CurBuffer);
   CurPtr = CurBuf->getBufferStart();

lib/TableGen/TGLexer.h

@@ -15,9 +15,10 @@
 #define TGLEXER_H
 
 #include "llvm/Support/DataTypes.h"
+#include "llvm/Support/SMLoc.h"
 #include <cassert>
+#include <map>
 #include <string>
-#include <vector>
 
 namespace llvm {
 class MemoryBuffer;
@@ -73,9 +74,13 @@ class TGLexer {
   /// CurBuffer - This is the current buffer index we're lexing from as managed
   /// by the SourceMgr object.
   int CurBuffer;
+
+public:
+  typedef std::map<std::string, SMLoc> DependenciesMapTy;
+private:
   /// Dependencies - This is the list of all included files.
-  std::vector<std::string> Dependencies;
-  
+  DependenciesMapTy Dependencies;
+
 public:
   TGLexer(SourceMgr &SrcMgr);
   ~TGLexer() {}
@@ -84,7 +89,7 @@ public:
     return CurCode = LexToken();
   }
 
-  const std::vector<std::string> &getDependencies() const {
+  const DependenciesMapTy &getDependencies() const {
     return Dependencies;
   }
   

lib/TableGen/TGParser.h

@@ -96,7 +96,7 @@ public:
   bool TokError(const Twine &Msg) const {
     return Error(Lex.getLoc(), Msg);
   }
-  const std::vector<std::string> &getDependencies() const {
+  const TGLexer::DependenciesMapTy &getDependencies() const {
     return Lex.getDependencies();
   }