Use requireExtensions() to check extension and turn on more tests.

Test/baseResults/preprocessor.cpp_style___FILE__.vert.out

 #extension GL_GOOGLE_cpp_style_line_directive : enable
 
 0
-#line 150 a.h
+
+#line 150 "a.h"
  "a.h"
+
 #line 24
  "a.h"
+
 #line 42
  "a.h"
-#line 30 b.cc
+
+#line 30 "b.cc"
  "b.cc"
+
 #line 10 3
  3
+
 #line 48
  3
+
 #line 4
  3
+
 #line 55 100
  100
-#line 1000 c
+
+#line 1000 "c"
  "c"
+
 #line 42 1
  1
-#line 42 this-is-a-quite-long-name-maybe-i-should-shorten-it
+
+#line 42 "this-is-a-quite-long-name-maybe-i-should-shorten-it"
  "this-is-a-quite-long-name-maybe-i-should-shorten-it"
 

Test/test-preprocessor-list

 preprocessor.cpp_style_line_directive.vert
+preprocessor.cpp_style___FILE__.vert
 preprocessor.edge_cases.vert
 preprocessor.errors.vert
 preprocessor.extensions.vert

glslang/MachineIndependent/preprocessor/Pp.cpp

@@ -604,7 +604,7 @@ int TPpContext::CPPline(TPpToken* ppToken)
     // "#line line source-string-number"
 
     int token = scanToken(ppToken);
-    const int directiveLoc = ppToken->loc.line;
+    const TSourceLoc directiveLoc = ppToken->loc;
     if (token == '\n') {
         parseContext.ppError(ppToken->loc, "must by followed by an integral literal", "#line", "");
         return token;
@@ -628,7 +628,8 @@ int TPpContext::CPPline(TPpToken* ppToken)
         parseContext.setCurrentLine(lineRes);
 
         if (token != '\n') {
-            if (parseContext.extensionTurnedOn(E_GL_GOOGLE_cpp_style_line_directive) && token == PpAtomConstString) {
+            if (token == PpAtomConstString) {
+                parseContext.requireExtensions(directiveLoc, 1, &E_GL_GOOGLE_cpp_style_line_directive, "filename-based #line");
                 // We need to save a copy of the string instead of pointing
                 // to the name field of the token since the name field
                 // will likely be overwritten by the next token scan.
@@ -646,7 +647,7 @@ int TPpContext::CPPline(TPpToken* ppToken)
         }
     }
     if (!fileErr && !lineErr) {
-        parseContext.notifyLineDirective(directiveLoc, lineToken, hasFile, fileRes, sourceName);
+        parseContext.notifyLineDirective(directiveLoc.line, lineToken, hasFile, fileRes, sourceName);
     }
     token = extraTokenCheck(PpAtomLine, ppToken, token);
 
@@ -965,8 +966,8 @@ int TPpContext::MacroExpand(int atom, TPpToken* ppToken, bool expandUndef, bool
         return 1;
 
     case PpAtomFileMacro: {
-        const char* current_file = parseContext.getCurrentLoc().name;
-        if (parseContext.extensionTurnedOn(E_GL_GOOGLE_cpp_style_line_directive) && current_file != nullptr) {
+        if (const char* current_file = parseContext.getCurrentLoc().name) {
+            parseContext.requireExtensions(ppToken->loc, 1, &E_GL_GOOGLE_cpp_style_line_directive, "filename-based __FILE__");
             sprintf(ppToken->name, "\"%s\"", current_file);
         } else {
             ppToken->ival = parseContext.getCurrentLoc().string;