[Support] On Windows, generate PDF files for graphs and open with associated viewer

[Meinersbur]

Summary

Windows system rarely have good PostScript viewers installed, but PDF viewers are common. So for viewing graphs, generate PDF files and open with the associated PDF viewer using cmd.exe's start command.

[dwiberg]

I agree that my PDF viewer is better than my PS viewer so I like direction of the patch. Many variable- and type names however still refers to PostScript which I think should be fixed.

[Meinersbur]

Removed "PS" from identifiers
make start wait if wait==true

[JakeVanAdrighem]

lib/Support/GraphWriter.cpp

202

Shouldn't all PSViewer references be changed here?

[Meinersbur]

Refactoring tool's rename did not rename within conditional compilation block of other system. Renamed manually.

[Meinersbur]

ping

[Meinersbur]

Change the prefix of the ViewerKind enum

[aaron.ballman]

I think it's close to being ready; one minor nit still (sorry for not bringing it up sooner).

lib/Support/GraphWriter.cpp

241

I think this code block should be moved into the case VK_CmdStart block below.

[Meinersbur]

Move VK_CmdStart-specific case into switch

Note that this doesn't work properly without D11876.

[aaron.ballman]

LGTM!

[Meinersbur]

Thank you for reviewing. I'll wait for D11876 before committing.

lib/Support/GraphWriter.cpp

if (S.TryFindProgram("xdot|xdot.py", ViewerPath)) {
     args.push_back(getProgramName(program));
 
     args.push_back(nullptr);
 
     errs() << "Running 'xdot.py' program... ";
     return ExecGraphViewer(ViewerPath, args, Filename, wait, ErrMsg);
   }
 
-  enum PSViewerKind { PSV_None, PSV_OSXOpen, PSV_XDGOpen, PSV_Ghostview };
-  PSViewerKind PSViewer = PSV_None;
+  enum ViewerKind {
+    VK_None,
+    VK_OSXOpen,
+    VK_XDGOpen,
+    VK_Ghostview,
+    VK_CmdStart
+  };
+  ViewerKind Viewer = VK_None;
 #ifdef __APPLE__
-  if (!PSViewer && S.TryFindProgram("open", ViewerPath))
-    PSViewer = PSV_OSXOpen;
+  if (!Viewer && S.TryFindProgram("open", ViewerPath))
+    Viewer = VK_OSXOpen;
+#endif
+  if (!Viewer && S.TryFindProgram("gv", ViewerPath))
+    Viewer = VK_Ghostview;
+  if (!Viewer && S.TryFindProgram("xdg-open", ViewerPath))
+    Viewer = VK_XDGOpen;
+#ifdef LLVM_ON_WIN32
+  if (!Viewer && S.TryFindProgram("cmd", ViewerPath)) {
+    Viewer = VK_CmdStart;
+  }
 #endif
-  if (!PSViewer && S.TryFindProgram("gv", ViewerPath))
-    PSViewer = PSV_Ghostview;
-  if (!PSViewer && S.TryFindProgram("xdg-open", ViewerPath))
-    PSViewer = PSV_XDGOpen;
 
-  // PostScript graph generator + PostScript viewer
+  // PostScript or PDF graph generator + PostScript/PDF viewer
   std::string GeneratorPath;
-  if (PSViewer &&
+  if (Viewer &&
       (S.TryFindProgram(getProgramName(program), GeneratorPath) ||
        S.TryFindProgram("dot|fdp|neato|twopi|circo", GeneratorPath))) {
-    std::string PSFilename = Filename + ".ps";
+    std::string OutputFilename =
+        Filename + (Viewer == VK_CmdStart ? ".pdf" : ".ps");
 
     std::vector<const char *> args;
     args.push_back(GeneratorPath.c_str());
+    if (Viewer == VK_CmdStart)
+      args.push_back("-Tpdf");
+    else
       args.push_back("-Tps");
     args.push_back("-Nfontname=Courier");
     args.push_back("-Gsize=7.5,10");
     args.push_back(Filename.c_str());
     args.push_back("-o");
-    args.push_back(PSFilename.c_str());
+    args.push_back(OutputFilename.c_str());
     args.push_back(nullptr);
 
     errs() << "Running '" << GeneratorPath << "' program... ";
 
     if (ExecGraphViewer(GeneratorPath, args, Filename, wait, ErrMsg))
       return true;
 
+    // The lifetime of StartArg must include the call of ExecGraphViewer
+    // because the args are passed as vector of char*.
+    std::string StartArg;
+
     args.clear();
     args.push_back(ViewerPath.c_str());
-    switch (PSViewer) {
-    case PSV_OSXOpen:
+    switch (Viewer) {
+    case VK_OSXOpen:
       args.push_back("-W");
-      args.push_back(PSFilename.c_str());
+      args.push_back(OutputFilename.c_str());
       break;
-    case PSV_XDGOpen:
+    case VK_XDGOpen:
       wait = false;
-      args.push_back(PSFilename.c_str());
+      args.push_back(OutputFilename.c_str());
       break;
-    case PSV_Ghostview:
+    case VK_Ghostview:
       args.push_back("--spartan");
-      args.push_back(PSFilename.c_str());
+      args.push_back(OutputFilename.c_str());
+      break;
+    case VK_CmdStart:
+      args.push_back("/S");
+      args.push_back("/C");
+      StartArg =
+          (StringRef("start ") + (wait ? "/WAIT " : "") + OutputFilename).str();
+      args.push_back(StartArg.c_str());
       break;
-    case PSV_None:
+    case VK_None:
       llvm_unreachable("Invalid viewer");
     }
     args.push_back(nullptr);
 
     ErrMsg.clear();
-    return ExecGraphViewer(ViewerPath, args, PSFilename, wait, ErrMsg);
+    return ExecGraphViewer(ViewerPath, args, OutputFilename, wait, ErrMsg);
   }
 
   // dotty
   if (S.TryFindProgram("dotty", ViewerPath)) {
     std::vector<const char *> args;
     args.push_back(ViewerPath.c_str());
     args.push_back(Filename.c_str());
     args.push_back(nullptr);