Refactor ExecuteAndWait to take StringRefs.

This simplifies some code which had StringRefs to begin with, and
makes other code more complicated which had const char* to begin
with.

In the end, I think this makes for a more idiomatic and platform
agnostic API.  Not all platforms launch process with null terminated
c-string arrays for the environment pointer and argv, but the api
was designed that way because it allowed easy pass-through for
posix-based platforms.  There's a little additional overhead now
since on posix based platforms we'll be takign StringRefs which
were constructed from null terminated strings and then copying
them to null terminate them again, but from a readability and
usability standpoint of the API user, I think this API signature
is strictly better.

llvm-svn: 334518

1 files changed, 27 insertions, 37 deletions

diff --git a/llvm/lib/Support/GraphWriter.cpp b/llvm/lib/Support/GraphWriter.cpp
index 794c6ba3a85..9335daffc3e 100644
--- a/llvm/lib/Support/GraphWriter.cpp
+++ b/llvm/lib/Support/GraphWriter.cpp
@@ -91,20 +91,18 @@ std::string llvm::createGraphFilename(const Twine &Name, int &FD) {
 }
 
 // Execute the graph viewer. Return true if there were errors.
-static bool ExecGraphViewer(StringRef ExecPath, std::vector<const char *> &args,
+static bool ExecGraphViewer(StringRef ExecPath, std::vector<StringRef> &args,
                             StringRef Filename, bool wait,
                             std::string &ErrMsg) {
-  assert(args.back() == nullptr);
   if (wait) {
-    if (sys::ExecuteAndWait(ExecPath, args.data(), nullptr, {}, 0, 0,
-                            &ErrMsg)) {
+    if (sys::ExecuteAndWait(ExecPath, args, None, {}, 0, 0, &ErrMsg)) {
       errs() << "Error: " << ErrMsg << "\n";
       return true;
     }
     sys::fs::remove(Filename);
     errs() << " done. \n";
   } else {
-    sys::ExecuteNoWait(ExecPath, args.data(), nullptr, {}, 0, &ErrMsg);
+    sys::ExecuteNoWait(ExecPath, args, None, {}, 0, &ErrMsg);
     errs() << "Remember to erase graph file: " << Filename << "\n";
   }
   return false;
@@ -158,22 +156,20 @@ bool llvm::DisplayGraph(StringRef FilenameRef, bool wait,
 #ifdef __APPLE__
   wait &= !ViewBackground;
   if (S.TryFindProgram("open", ViewerPath)) {
-    std::vector<const char *> args;
-    args.push_back(ViewerPath.c_str());
+    std::vector<StringRef> args;
+    args.push_back(ViewerPath);
     if (wait)
       args.push_back("-W");
-    args.push_back(Filename.c_str());
-    args.push_back(nullptr);
+    args.push_back(Filename);
     errs() << "Trying 'open' program... ";
     if (!ExecGraphViewer(ViewerPath, args, Filename, wait, ErrMsg))
       return false;
   }
 #endif
   if (S.TryFindProgram("xdg-open", ViewerPath)) {
-    std::vector<const char *> args;
-    args.push_back(ViewerPath.c_str());
-    args.push_back(Filename.c_str());
-    args.push_back(nullptr);
+    std::vector<StringRef> args;
+    args.push_back(ViewerPath);
+    args.push_back(Filename);
     errs() << "Trying 'xdg-open' program... ";
     if (!ExecGraphViewer(ViewerPath, args, Filename, wait, ErrMsg))
       return false;
@@ -181,10 +177,9 @@ bool llvm::DisplayGraph(StringRef FilenameRef, bool wait,
 
   // Graphviz
   if (S.TryFindProgram("Graphviz", ViewerPath)) {
-    std::vector<const char *> args;
-    args.push_back(ViewerPath.c_str());
-    args.push_back(Filename.c_str());
-    args.push_back(nullptr);
+    std::vector<StringRef> args;
+    args.push_back(ViewerPath);
+    args.push_back(Filename);
 
     errs() << "Running 'Graphviz' program... ";
     return ExecGraphViewer(ViewerPath, args, Filename, wait, ErrMsg);
@@ -192,15 +187,13 @@ bool llvm::DisplayGraph(StringRef FilenameRef, bool wait,
 
   // xdot
   if (S.TryFindProgram("xdot|xdot.py", ViewerPath)) {
-    std::vector<const char *> args;
-    args.push_back(ViewerPath.c_str());
-    args.push_back(Filename.c_str());
+    std::vector<StringRef> args;
+    args.push_back(ViewerPath);
+    args.push_back(Filename);
 
     args.push_back("-f");
     args.push_back(getProgramName(program));
 
-    args.push_back(nullptr);
-
     errs() << "Running 'xdot.py' program... ";
     return ExecGraphViewer(ViewerPath, args, Filename, wait, ErrMsg);
   }
@@ -235,18 +228,17 @@ bool llvm::DisplayGraph(StringRef FilenameRef, bool wait,
     std::string OutputFilename =
         Filename + (Viewer == VK_CmdStart ? ".pdf" : ".ps");
 
-    std::vector<const char *> args;
-    args.push_back(GeneratorPath.c_str());
+    std::vector<StringRef> args;
+    args.push_back(GeneratorPath);
     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(Filename);
     args.push_back("-o");
-    args.push_back(OutputFilename.c_str());
-    args.push_back(nullptr);
+    args.push_back(OutputFilename);
 
     errs() << "Running '" << GeneratorPath << "' program... ";
 
@@ -258,31 +250,30 @@ bool llvm::DisplayGraph(StringRef FilenameRef, bool wait,
     std::string StartArg;
 
     args.clear();
-    args.push_back(ViewerPath.c_str());
+    args.push_back(ViewerPath);
     switch (Viewer) {
     case VK_OSXOpen:
       args.push_back("-W");
-      args.push_back(OutputFilename.c_str());
+      args.push_back(OutputFilename);
       break;
     case VK_XDGOpen:
       wait = false;
-      args.push_back(OutputFilename.c_str());
+      args.push_back(OutputFilename);
       break;
     case VK_Ghostview:
       args.push_back("--spartan");
-      args.push_back(OutputFilename.c_str());
+      args.push_back(OutputFilename);
       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());
+      args.push_back(StartArg);
       break;
     case VK_None:
       llvm_unreachable("Invalid viewer");
     }
-    args.push_back(nullptr);
 
     ErrMsg.clear();
     return ExecGraphViewer(ViewerPath, args, OutputFilename, wait, ErrMsg);
@@ -290,10 +281,9 @@ bool llvm::DisplayGraph(StringRef FilenameRef, bool wait,
 
   // 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);
+    std::vector<StringRef> args;
+    args.push_back(ViewerPath);
+    args.push_back(Filename);
 
 // Dotty spawns another app and doesn't wait until it returns
 #ifdef _WIN32