HLSL: Fix #1655; use "" for nullptr file names. Needs test cases.

diff --git a/glslang/Include/Common.h b/glslang/Include/Common.h
index b136dde..98e5a1a 100644
--- a/glslang/Include/Common.h
+++ b/glslang/Include/Common.h

@@ -250,7 +250,8 @@
             return nullptr;
         return name->c_str();
     }
-    TString* name; // descriptive name for this string
+    const char* getFilenameStr() const { return name == nullptr ? "" : name->c_str(); }
+    TString* name; // descriptive name for this string, when a textual name is available, otherwise nullptr
     int string;
     int line;
     int column;

diff --git a/glslang/MachineIndependent/preprocessor/PpContext.h b/glslang/MachineIndependent/preprocessor/PpContext.h
old mode 100755
new mode 100644
index 7b8b22e..73fe5e3
--- a/glslang/MachineIndependent/preprocessor/PpContext.h
+++ b/glslang/MachineIndependent/preprocessor/PpContext.h

@@ -549,9 +549,9 @@
               scanner.setLine(startLoc.line);
               scanner.setString(startLoc.string);
 
-              scanner.setFile(startLoc.name->c_str(), 0);
-              scanner.setFile(startLoc.name->c_str(), 1);
-              scanner.setFile(startLoc.name->c_str(), 2);
+              scanner.setFile(startLoc.getFilenameStr(), 0);
+              scanner.setFile(startLoc.getFilenameStr(), 1);
+              scanner.setFile(startLoc.getFilenameStr(), 2);
         }
 
         // tInput methods:

diff --git a/hlsl/hlslParseHelper.cpp b/hlsl/hlslParseHelper.cpp
old mode 100755
new mode 100644
index d6dc2e8..72edbd7
--- a/hlsl/hlslParseHelper.cpp
+++ b/hlsl/hlslParseHelper.cpp

@@ -133,7 +133,7 @@
         // Print a message formated such that if you click on the message it will take you right to
         // the line through most UIs.
         const glslang::TSourceLoc& sourceLoc = input.getSourceLoc();
-        infoSink.info << sourceLoc.name->c_str() << "(" << sourceLoc.line << "): error at column " << sourceLoc.column
+        infoSink.info << sourceLoc.getFilenameStr() << "(" << sourceLoc.line << "): error at column " << sourceLoc.column
                       << ", HLSL parsing failed.\n";
         ++numErrors;
         return false;